BACKGROUND OF THE INVENTION

The invention relates to a scroll compressor.

The underlying problem of the invention is to improve the scroll compressor and its operation.

SUMMARY OF THE INVENTION

In one aspect of the invention the problem is solved by a scroll compressor which comprises two scroll bodies, one of the two scroll bodies is a stationary scroll body with a scroll wrap and the other scroll body of the two scroll bodies is a moveable scroll body with a scroll wrap, the scroll wraps of the two scroll bodies engage each other forming, in particular during a respective compression cycle, at least one compression chamber. The stationary scroll body comprises a base plate and the stationary scroll body has two opposing sides with respect to the base plate, in particular a first side of the two opposing sides is arranged on one side of the base plate and a second side of the two opposing sides is arranged on the other side of the base plate. The scroll wrap of the stationary scroll body is arranged on a first side of the two opposing sides. On a second side of the two opposing sides a pressure pocket is formed and a vent passage is provided through the base plate from the first side to the second side. The vent passage opens at the second side into the pressure pocket. The vent passage has an opening at the first side. The opening at the first side is in the following also referred to as the first opening. The opening at the first side is arranged such that the vent passage is fluidly connected to the at least one compression chamber during a compression cycle of the at least one compression chamber at least during a time span before the at least one compression chamber is fluidly connected to a discharge chamber of the scroll compressor and at least during a time span of the period when the at least one compression chamber is fluidly connected to the discharge chamber of the scroll compressor.

In particular, therewith at least one pressure pocket is fluidly connected to the at least one compression chamber during its respective compression cycle at least during a time span before the at least one compression chamber is fluidly connected to the discharge chamber and therefore when the at least one compression chamber is fluidly separated from the discharge chamber as well as during a time span of the period when the at least one compression chamber is fluidly connected to the discharge chamber.

In particular, a gaseous medium in the at least one pressure pocket is in fluid contact with a gaseous medium in the at least one compression chamber before the at least one compression chamber is fluidly connected to the discharge chamber and therefore when the pressure of the gaseous medium contained in that at least one compression chamber is at a pressure which depends on a suction pressure with which the gaseous medium enters the at least one compression chamber at the very beginning of the compression cycle and on the course of the compression cycle and the gaseous medium is also in fluid contact with the gaseous medium in the at least one compression chamber at least during a time span of the period when the compression chamber is fluidly connected to the discharge chamber and therefore when the therein contained gaseous medium is at a discharge pressure.

In particular, an advantage of embodiments of the invention is that the pressure of the gaseous medium in the at least one pressure pocket mimics more closely the variation of the pressure of the gaseous medium contained in the at least one compression chamber and because the pressure of the gaseous medium in the at least one pressure pocket acts against a force exerted by the compressed gaseous medium in the at least one compression chamber advantageously a load between the moveable scroll body and the stationary scroll body is more consistent during a compression cycle. For example, in embodiments of the invention the arrangement of the at least one pressure pocket and of the vent passage allows for higher pressure ratios of the discharge pressure to the suction pressure.

In one aspect of the invention the underlying problem is solved in the alternative or in addition by a scroll compressor which comprises two scroll bodies, one of the two scroll bodies is a stationary scroll body with a scroll wrap and the other scroll body of the two scroll bodies is a moveable scroll body with a scroll wrap, the scroll wraps of the two scroll bodies engage each other forming at least one compression chamber, in particular during a respective compression cycle. The stationary scroll body comprises a base plate and has two opposing sides with respect to the base plate, in particular a first side of the two opposing sides on one side of the base plate and a second side of the two opposing sides is on the other side of the base plate. In particular, the base plate is in between the two opposing sides. The scroll wrap of the stationary scroll body is arranged on the first side of the two opposing sides and on a second side of the two opposing sides one pressure pocket is formed or several pressure pockets are formed and for each pressure pocket at least one vent passage is provided through the base plate from the first side to the second side and each vent passage opens into the respective pressure pocket and each vent passage has an opening at the first side, in particular the respective opening at the first side is in particular also referred to as the first opening. The opening at the first side of each vent passage is arranged such that the vent passage is fluidly connected to the at least one compression chamber at least during a time span during a respective compression cycle of the at least one compression chamber. Gaseous medium is contained in the one pressure pocket or in the several pressure pockets and at least during operation of the scroll compressor due to a pressure of the gaseous medium in the one pressure pocket or in the several pressure pockets a force is exerted on the stationary scroll body, in particular a force is exerted on the stationary scroll body in an axial direction with respect to a central axis of the stationary scroll body, and the force exerted by the pressure of the gaseous medium in the one pressure pocket or in the several pressure pockets is dependent on a suction pressure at which the gaseous medium enters the at least one compression chamber at the very beginning of the respective compression cycle and on a discharge pressure which a gaseous medium in a discharge chamber of the scroll compressor has.

Accordingly, the force exerted by the gaseous medium contained in the one pressure pocket or in the several pressure pockets is dependent on the suction pressure and the discharge pressure and for example mimics therefore more closely the force which is associated to the pressure of the gaseous medium contained in the at least one pressure chamber and which is exerted on the two scroll bodies and a more consistent load between the two scroll bodies is obtained.

For example, because the force of the gaseous medium contained in the one pressure pocket or in the several pressure pockets depends on both, the suction pressure and the discharge pressure, in embodiments of the invention higher pressure ratios of the discharge pressure to the suction pressure are possible, which is in particular advantageous for compressor assemblies with an economizer.

In advantageous embodiments there is exactly one pressure pocket formed on the second side of the stationary scroll body which is connected fluidly to at least one vent passage through the base plate of the stationary scroll body and the at least one vent passage has an opening at the first side of the stationary scroll body, in particular at the base plate such that the opening opens into an involute space between the scroll wrap of the stationary scroll body. In other preferred embodiments, there are several pressure pockets formed on the second side of the stationary scroll body each of which is fluidly connected to at least one respective vent passage provided through the base plate and each vent passage has an opening at the first side of the stationary scroll body, in particular the openings at the first side of the vent passages are arranged at the base plate of the stationary scroll body and such that they open into an involute space between the scroll wrap of the stationary scroll body.

In particular, the several pressure pockets are fluidly connected by their respective vent passage to the at least one compression chamber in several, different time spans during the compression cycle of the at least one compression chamber

In particular, the gaseous medium has in different pressure pockets of the several pressure pockets different pressures.

In some preferred embodiments one pressure pocket is and/or at least some, for example all, of the several pressure pockets are fluidly connected to exactly one vent passage.

For example, this provides for a constructive simple solution.

In some advantageous embodiments one pressure pocket is or at least some, for example all, of the several pressure pockets are fluidly connected to several, in particular two, vent passages. For example, this provides for a more flexible solution, in particular because with the several vent passages for one pressure pocket fluid connections to different compression chambers can be established and/or by the design of the several vent passages the pressure in the pressure pocket can be realized to mimic more closely the pressure in the one compression chamber or in the several compression chambers and therefore advantageously the moveable scroll body moves more smoothly.

In particular, during a compression cycle there are two compression chambers which are at least essentially in the same condition, in particular in one or several conditions as described below, and/or the gaseous medium in the two compression chambers has at least essentially the same pressure during the compression cycle. Such two compression chambers will be called in the following also a pair of compression chambers.

In preferred embodiments at least one pressure pocket is fluidly connected by at least one vent passage to at least one compression chamber of a pair of compression chambers.

In some preferred embodiments, at least one pressure pocket is fluidly connected by one vent passage to exactly one compression chamber of a pair of compression chambers.

In some advantageous embodiments at least one pressure pocket is fluidly connected in particular by two vent passages to both compression chambers of a pair of compression chambers.

Preferably, a first opening of a vent passage which is designed to open into one compression chamber of a pair of compression chambers is arranged such that it only opens into the one compression chamber of the pair of compression chambers but does not open into the other compression chamber of the pair of compression chambers. For example, such a design can be realized by placing the first opening off center between the scroll wraps of the stationary scroll body and/or by designing the size of the first opening sufficiently small in particular to be covered by the scroll wrap of the moveable scroll body as long as the first opening does not open into the respective compression chamber.

In the following the term "at least one pressure pocket" and "the pressure pocket", "at least one vent passage" and "one vent passage", and "at least one opening" and "one opening" in connection with a feature is to be understood that in preferred embodiments the one pressure pocket or the one vent passage or the one opening has that feature or at least one of the several pressure pockets or vent passages or openings has that feature or that at least some, for example all, of the several pressure pockets or vent passages or openings have that feature, respectively.

In advantageous embodiments the one pressure pocket and/or the one passage and/or the one opening or at least one of the several pressure pockets and/or vent passages and/or openings have a combination of the following features.

In preferred embodiments, at least some of the several pressure pockets and/or vent passages and/or openings have a combination of the following features and in particular some of the several pressure pockets and/or vent passages and/or openings have some features in common and differ in other features.

Further details about the fluid connection between the at least one pressure pocket and the at least one compression chamber and about the pressure of the gaseous medium within the at least one from pressure pocket and about the force exerted by the gaseous medium contained in the at least one pressure pocket have not been given so far. During a compression cycle of at least one compression chamber, in particular during a respective compression cycle of each of the several compression chambers, the two scroll bodies are arranged in several different configurations to each other, in particular due to the orbiting motion of the moveable scroll body relative to the stationary scroll body.

The several different configurations of the two scroll bodies relative to each other impose different conditions on the at least one compression chamber.

The different conditions imposed by the several configurations of the two scroll bodies comprise in particular a first condition in which the at least one compression chamber is fluidly connected to an intake area.

In particular, in the first condition the gaseous medium enters the at least one compression chamber at a suction pressure.

In particular, in the first condition the at least one compression chamber is fluidly separated from the discharge chamber of the scroll compressor.

In particular, at the beginning of a respective compression cycle of a compression chamber, the two scroll bodies are in the configurations which impose the first condition on the compression chamber.

The different conditions imposed by the several configurations of the two scroll bodies comprise in particular a second condition in which the at least one compression chamber is fluidly separated from the intake area and the discharge chamber of the scroll compressor. In particular, there are some configurations of the several configurations of the two scroll bodies relative to each other which impose the second condition on the at least one compression chamber and the volume of the at least one compression chamber becomes smaller with subsequent configurations during the compression cycle for compressing the gaseous medium, in particular for increasing the pressure of the gaseous medium contained in the at least one compression chamber from the suction pressure to a maximal intermediate pressure.

In particular, towards an end of a compression cycle, right before the compression chamber opens into the discharge chamber, the gaseous medium contained in the at least one compression chamber has a pressure to which it is referred to before and in the following as "the maximal intermediate pressure".

In particular, a location of the compression chamber in the configurations of the two scroll bodies which impose the second condition is arranged differently along the spiral form of the scroll wraps and in subsequent configurations imposing the second condition during a compression cycle the location of the compression chamber moves radially inwards with respect to the central axis of the stationary scroll body and in a direction from the intake area towards the compression chamber along the spiral form of the scroll bodies.

In particular, the different conditions imposed by the several configurations of the two scroll bodies comprise a third condition in which the at least one compression chamber is fluidly connected to the discharge chamber of the scroll compressor.

In particular, the gaseous medium in the at least one compression chamber is at the discharge pressure when the third condition is imposed on the at least one compression chamber. In particular, the at least one compression chamber is fluidly separated from the intake area when the third condition is imposed on the at least one compression chamber.

In particular, during the respective compression cycle the separate configurations of the two scroll bodies relative to each other impose at the beginning the first condition on the at least one compression chamber and at the end of the compression cycle the third condition is imposed on the at least one compression chamber and in a phase in between the second condition is imposed on the at least one compression chamber.

In advantageous embodiments, the opening of the vent passage is arranged at the first side of the stationary scroll body such that the vent passage is fluidly connected to the at least one compression chamber in at least one configuration of the two scroll bodies relative to each other in which the second condition is imposed on the at least one compression chamber and in at least one configuration of the two scroll bodies relative to each other in which the third condition is imposed on the at least one compression chamber.

Preferably, the opening of the vent passage is arranged at the first side of the stationary scroll body such that the vent passage is fluidly connected to the at least one compression chamber in at least some of the configurations imposing the second condition on the at least one compression chamber and in which the two scroll bodies are at the end of the phase in which they are arranged in configurations relative to each other which impose the second condition on the at least one compression chamber.

Advantageously, the opening of the vent passage at the first side of the stationary scroll body is arranged such that it opens into the at least one compression chamber during its respective compression cycle at least during a time span when the gaseous medium in the at least one compression chamber has a pressure which depends on the suction pressure and on the course of the compression cycle but not on the discharge pressure. In particular, the opening of the vent passage at the first side of the stationary scroll body is arranged such that it opens into the at least one compression chamber during its respective compression cycle at least during a time span when the gaseous medium in the at least one compression chamber has a pressure which is between the suction pressure and the discharge pressure.

In some embodiments the maximal intermediate pressure equals the discharge pressure but in other embodiments the maximal intermediate pressure is larger than the discharge pressure and in other embodiments the maximal intermediate pressure is smaller than the discharge pressure.

The value of the maximal intermediate pressure with respect to the discharge pressure depends on various circumstances, for example on the operational mode in which and/or the power at which the scroll compressor is operated and circumstances downstream the discharge chamber, in particular downstream an outlet port of the scroll compressor in a system in which the scroll compressor operates.

In particular, at least one pressure pocket is fluidly connected to the at least one compression chamber when the gaseous medium in the at least one compression chamber is at the maximal intermediate pressure and in particular in a time span before the gaseous medium in the at least one compression chamber reaches the maximal intermediate pressure and/or in a time span after the gaseous medium in the at least one compression chamber has reached the maximal intermediate pressure.

In preferred embodiments, the one or at least one pressure pocket is fluidly connected by its respective vent passage to the at least one compression chamber during the respective compression cycle at least during a time span when the gaseous medium in the at least one compression chamber is at a pressure which is dependent on the suction pressure and on the course of the compression cycle but is in particular not dependent on the discharge pressure.

In particular, in such embodiments the pressure of the gaseous medium in the pressure pocket mimics closely the pressure and in particular its evolution in time during a compression cycle and the gaseous medium contained in the pressure pocket acts more consistently against the force exerted by the compressed gaseous medium in the at least one compression chamber.

In particular, the pressure of the gaseous medium contained in the pressure pocket varies in time, in particular between a lowest pressure and a highest pressure.

In particular, the lowest pressure is larger than the suction pressure and in particular larger than a pressure of the gaseous medium contained in the at least one compression chamber at a point in time of the respective compression cycle when the pressure pocket is for the first time in that compression cycle fluidly connected to the at least one compression chamber.

In particular, the highest pressure is smaller than the larger one of the maximal intermediate pressure and the discharge pressure, in particular smaller than the discharge pressure and/or the maximal intermediate pressure. In particular, the pressure of the gaseous medium in the pressure pocket is an averaged pressure, averaged over the pressures which the gaseous medium in the at least one compression chamber exhibit during the time span in which the pressure pocket and the at least one compression chamber are fluidly connected. For example, also the averaged pressure varies in time during operation of the scroll compressor and in particular during a respective compression cycle of a compression chamber.

In advantageous embodiments, the pressure pocket and the vent passage are designed such that during operation of the scroll compressor at least one of the lowest pressure and/or the averaged pressure of the gaseous medium in the pressure pocket during a compression cycle equals to or is larger than 75 % of the discharged pressure.

The gaseous medium contained in the at least one compression chamber gets compressed during a compression cycle and therefore the gaseous medium acts with a force on the stationary scroll body and the moveable scroll body which form the compression chamber and in particular this force varies during a respective compression cycle between a minimal force and a maximal force.

Preferably, the one pressure pocket or at least one pressure pocket and its respective vent passage are designed such that during operation of the scroll compressor a force exerted on the stationary scroll body by the gaseous medium contained in the one or at least one pressure pocket is equal to or larger than the total minimal force exerted by the gaseous medium in the at least one compression chamber or in the several compression chambers on the stationary scroll body and/or is the same as or smaller than one and a half times the total maximal force exerted by the gaseous medium contained in the at least one compression chamber or in the several compression chambers on the stationary scroll body. In advantageous embodiments, the several pressure pockets and their respective vent passages are designed such that during operation of the scroll compressor the total force exerted by the gaseous media contained in the several pressure pockets on the stationary scroll body is equal to or larger than the total minimal force exerted by the gaseous medium in the at least one compression chamber or in the several compression chambers on the stationary scroll body and/or is equal to or smaller than one and a half times the total maximal force exerted by the gaseous medium in the at least one compression chamber or in the several compression chambers on the stationary scroll body.

In order to obtain a specific pressure of the contained gaseous medium and/or a specific force exerted by the contained gaseous medium on the stationary scroll body, the design of the pressure pocket and/or the vent passage is adapted in particular with respect to a shape and/or to a size of the part of the stationary scroll body limiting the pressure pocket and/or to a size of the pressure pocket and/or to a size and an arrangement of the vent passage, for example a diameter of the vent passage which is measured perpendicular to an extension direction of the vent passage being directed from the opening at the first side to the opening at the second side and/or to an arrangement and/or to a shape of a closing element which together with the part of the stationary scroll body limits the volume of the pressure pocket.

In particular, the pressure of the gaseous medium contained in the pressure pocket also depends on the operation mode in which and/or the power at which the scroll compressor is operated and for example on the course of a respective compression cycle. Accordingly, the force exerted on the stationary scroll body by the gaseous medium contained in the pressure pocket depends on the operation mode in which and/or the power at which the scroll compressor is operated and for example on the course of the respective compression cycle, too. Advantageously, the pressure of the gaseous medium contained in the pressure pocket during operation of the scroll compressor is sufficiently large to act against the pressure of the gaseous medium contained in the at least one compression chamber and the associated force acting on the stationary scroll body.

In particular, the pressure of the gaseous medium contained in the pressure pocket is sufficiently large to press the stationary scroll body sufficiently strong against the moveable scroll body for establishing a fluid tight connection between the two scroll bodies form the at least one compression chamber.

With respect to the vent passage and its openings no further details have been provided so far.

In particular, the vent passage is designed such that gaseous medium is able to flow between the at least one compression chamber and the respective pressure pocket when the pressure pocket and the at least one compression chamber are fluidly connected.

In advantageous embodiments, the vent passage allows for exchange of gaseous medium between the at least one compression chamber and the pressure pocket when they are fluidly connected but the vent passage is sufficiently small to prevent an instantaneous pressure balance between the at least one compression chamber and the pressure pocket when the pressure pocket and the at least one compression chamber are fluidly connected by the vent passage. For example, an equalization of the pressures of the gaseous media within the compression chamber and the pressure pocket when both are fluidly connected requires a longer time than the time span in which the at least one compression chamber is fluidly connected to the discharge chamber during a compression cycle and/or requires a longer time than the time span in which the pressure pocket and the at least one compression chamber are fluidly connected to each other during a compression cycle.

For example, due to the exchange of gaseous medium the pressure of the gaseous medium in the pressure pocket is enabled to mimic the variation of the pressure of the gaseous medium contained in the at least one compression chamber but on the other hand the pressure of the gaseous medium in the pressure pocket is averaged over the time span in which the pressure pocket and the at least one compression chamber are fluidly connected in order to have a more balanced force acting by the gaseous medium in the pressure pocket on the stationary scroll body.

In particular, towards the end of the time span in which the pressure pocket and the at least one compression chamber are fluidly connected, the pressure of the gaseous medium in the pressure pocket does not become such large as the pressure of the gaseous medium within the at least one compression chamber and therefore when the gaseous medium in the last one compression chamber is discharged and does not counteract anymore against the pressure of the gaseous medium in the pressure pocket, the gaseous medium in the pressure pocket is not at a too large pressure and therefore in particular more similar to a pressure of gaseous medium in other compression chambers formed between the two scroll bodies and acts more similar to the forces associated to these pressures.

In particular, the opening of the vent passage at the first side of the stationary scroll body is arranged at a surface of the base plate of the stationary scroll body. In particular, the opening of the vent passage at the first side of the stationary scroll body opens into an involute space formed between the scroll wrap of the stationary scroll body.

In particular, the opening of the vent passage at the second side of the stationary scroll body is arranged at a surface of the base plate of the stationary scroll body which limits the pressure pocket.

With respect to the pressure pocket, in particular its design, no further details have been given so far.

The one pressure pocket or the several pressure pockets can be designed in various ways.

In preferred embodiments, the pressure pocket is formed partly by the stationary scroll body and partly by a closing element which is fluid tight connected to the part of the stationary scroll body which partly forms the pressure pocket.

In particular, a seal arrangement is provided, which or at least a part of which connects the closing element and the part of this stationary scroll body fluid tight.

In some advantageous embodiments, the closing element and the stationary scroll body are fluid tight connected by a floating seal arrangement.

In particular, a in particular limited relative motion between the stationary scroll body and the closing element, in particular in the axial direction with respect to the central axis of the stationary scroll body, is enabled by the floating seal arrangement. Advantageously, with enabling an in particular limited mobility of the stationary scroll body in particular in the axial direction with respect to the central axis of the stationary scroll body, the stationary scroll body is able to react on the various varying pressures in the at least one compression chamber during a compression cycle and the relative motion between the stationary scroll body and the moveable scroll body is improved, for example the moveable scroll body is enabled to move smoother along its orbital path around the central axis of the stationary scroll body.

In particular, a portion of the base plate of the stationary scroll body limits the pressure pocket.

Preferably, the portion of the base plate of the stationary scroll body which limits the pressure pocket surrounds the central axis of the stationary scroll body and is for example ring-like shaped.

Preferably, the portion of the base plate of the stationary scroll body which limits the pressure pocket and in particular its surface limiting the pressure pocket is designed such that the force exerted by the gaseous medium in the pressure pocket is optimized for smooth operation of the compression unit comprising the stationary scroll body and the moveable scroll body.

In an advantageous embodiment, an inner ridge and an outer ridge each of which surround a central axis of the stationary scroll body are arranged at the second side of the stationary scroll body and project from the base plate scroll body, in particular at least essentially in the axial direction of the central axis of the stationary scroll body. Preferably, the one pressure pocket or at least one pressure pocket of the several pressure pockets is arranged in radial direction of the central axis of the stationary scroll body between the inner ridge and the outer ridge.

In particular, each of the several pressure pockets is arranged in radial direction of the central axis of the stationary scroll body between the inner ridge and the outer ridge.

In particular, the inner ridge partly limits the one pressure pocket or at least one of the several pressure pockets.

In particular, the outer ridge partly limits the one pressure pocket or at least one of the several pressure pockets.

Advantageously, the one pressure pocket is formed in radial direction of the central axis of the stationary scroll body between the inner ridge and the outer ridge, both of which in particular limit partly the one pressure pocket and preferably form together with a portion of the base plate the part of the stationary scroll body which partly limits the pressure pocket.

In particular, a radial distance of the inner ridge from the central axis of the stationary scroll body is smaller than a radial distance of the outer ridge from the central axis of the stationary scroll body.

Preferably, the inner ridge surrounds a discharge breakthrough through the base plate of the stationary scroll body. In advantageous embodiments, a radially outward directed surface of the outer ridge has a radial distance from the central axis of the stationary scroll body which is smaller than a radial extension of the base plate of the stationary scroll body, with the radial extension of the base plate being for example measured from the central axis of the stationary scroll body to a radially outward directed surface at the radially outermost side of the base plate.

In advantageous embodiments, the base plate has an outer portion which is for example essentially ring-like shaped and which is in radial direction with respect to the central axis of the stationary scroll body arranged between the outer ridge and the radially outermost end of the base plate.

For example, the base plate of the stationary scroll body has at its outer portion at the second side a surface, which is in particular at least approximately perpendicular arranged to the axial direction of the central axis of the stationary scroll body, and the surface surrounds the outer ridge and for example extends in the radial direction of the central axis of the stationary scroll body from the outer ridge to the radially outermost end of the base plate.

For example, the radial distance of the radially outer side of the outer ridge from the central axis of the stationary scroll body is the same as or smaller than 95 % of the radial extension of the base plate, in particular the same as or smaller than 90 % of the radial extension of the base plate, for example the same as or smaller than 85 % of the radial extension of the base plate.

In particular, the surface of the outer portion of the base plate has in the radial direction with respect to the central axis of the stationary scroll body an extension which is the same as or larger than 5 % of the radial extension of the base plate, in particular the same as or larger than 10 % of the radial extension of the base plate, for example the same as or larger than 15 % of the radial extension of the base plate. In particular, the closing element is arranged in radial direction to the central axis of the stationary scroll body between the inner ridge and the outer ridge for limiting the pressure pocket.

For example, the several pressure pockets are arranged in radial direction of the central axis between the inner ridge and the outer ridge and their respective closing elements are arranged in the radial direction of the central axis of the stationary scroll body between the inner ridge and the outer ridge.

In preferred embodiments with one pressure pocket there is an inner seal between the inner ridge and the closing element and an outer seal between the closing element and the outer ridge.

In preferred embodiments with several pressure pockets there is an inner seal between the inner ridge and the closing element of the radially innermost arranged pressure pocket and an outer seal between the outer ridge and the closing element of the radially outermost arranged pressure pocket, with the radial direction being with respect to the central axis of the stationary scroll body.

For example, in embodiments with several pressure pockets there is one intermediate ridge or are several intermediate ridges which are arranged in the radial direction of the central axis of the stationary scroll body between the inner ridge and the outer ridge and which separate respective pressure pockets and in particular there are one intermediate seal or several intermediate seals which seal between a respective intermediate ridge and at least one closing element of a pressure pocket arranged next to the intermediate ridge. Advantageously, the closing element limits the pressure pocket in the axial direction with respect to the central axis of the stationary scroll body and in particular opposite to the base plate of the stationary scroll body.

In preferred embodiments the one closing element or the several closing elements are part of a seal member and in particular parts of a seal arrangement which seals the discharge chamber from a low pressure environment around the stationary scroll body.

In particular the seal arrangement is a floating seal arrangement.

In advantageous embodiments, the seal member is in fluid tight connection with another seal member of the seal arrangement, for example a separator plate which for example separates an outlet chamber from the low pressure environment around the stationary scroll body.

The other seal member is in particular in fluid tight connection with the compressor housing, preferably fluid tight fixed to the compressor housing.

Advantageously, the seal member is pressed directly or indirectly, for example with a gasket in between, against the other seal member at least among others by the pressure of the gaseous medium contained in the one pressure pocket or in the several pressure pockets.

In one aspect of the invention the underlying problem mentioned at the beginning is solved in the alternative or in addition by a scroll compressor comprising two scroll bodies, one of the two scroll bodies is a stationary scroll body with a scroll wrap and the other scroll body of the two scroll bodies is a moveable scroll body with a scroll wrap, the scroll wraps of the two scroll bodies engage each other to form at least one compression chamber in particular during a respective compression cycle. The stationary scroll body comprises a base plate and has two opposing sides with respect to the base plate, that is in particular that the first side of the stationary scroll body is arranged on one side of the base plate and the second side of the stationary scroll body is arranged on the upper side of the base plate, and on a first side of the two opposing sides the scroll wrap of the stationary scroll body is arranged and on the second side of the two opposing sides at least two pressure pockets are formed and each of the at least two pressure pockets is connected to at least one respective vent passage. The vent passages of the at least two pressure pockets are formed through the base plate of the stationary scroll body from the second side at which they open into their respective pressure pocket to the first side at which each vent passage has an opening which is arranged to fluidly connect the respective pressure pocket with the at least one compression chamber in a time span during a compression cycle of the at least one compression chamber.

For example, in some embodiments of the invention an advantage is that the at least two pressure pockets and the therein contained gaseous medium act onto the stationary scroll body and because there are several pressure pockets the force exerted by the pressurized gaseous medium can be better adapted for a smoother motion of the moveable scroll body relative to the stationary scroll body.

In particular, because there are at least two pressure pockets for example each of them can be designed such that the gaseous medium in the at least two pressure pockets mimic with their respective pressures more closely the various different pressures of the gaseous medium contained in the at least one compression chamber during the compression cycle and in particular the pressures of gaseous medium in several compression chambers and therefore the forces acting on the stationary scroll body exerted from the gaseous medium contained in the at least one compression chamber or in the several compression chambers and exerted by the gaseous medium contained in the at least two pressure pockets are more balanced. In preferred embodiments of this aspect of the invention the scroll compressor and in particular its stationary and its moveable scroll body and/or at least one or several of the at least two pressure pockets and their at least one respective vent passages, have one or several of the above described features.

Advantageous embodiments of this aspect of the invention and/or of the aspects of the invention described above have one or more of the features described in the following.

In particular, at least two pressure pockets or the at least two pressure pockets are fluidly connected to the at least one compression chamber during different time spans during a compression cycle, in particular during a respective compression cycle of the at least one compression chamber.

Accordingly, the at least one compression chamber is fluidly connected to different pressure pockets in different time spans, and therefore different pressures develop in the different pressure pockets.

For example, the different time spans overlap partly.

In other preferred embodiments the different time spans are separate from each other, that is, two different time spans have no common point in time.

In particular, at least one pressure pocket is fluidly connected by its respective vent passage to the at least one compression chamber at least in a time span of the period when the compression chamber opens into the discharge chamber of the scroll compressor.

In some preferred embodiments, at least one pressure pocket is fluidly connected to the at least one compression chamber only in a time span when the at least one compression chamber opens into the discharge chamber. In some preferred embodiments, at least one pressure pocket is fluidly connected to the at least one compression chamber in a time span when the at least one compression chamber is fluidly separated from the discharge chamber and in a time span when the at least one compression chamber opens into the discharge chamber.

In particular, at least one of the several pressure pockets, in particular of the at least two pressure pockets, is fluidly connected to the at least one compression chamber at least in a time span when the compression chamber is fluidly separated from the discharge chamber and from the intake area.

Advantageously, at least some of the several pressure pockets, in particular of the at least two pressure pockets, are fluidly connected to the at least one compression chamber at least partly during the period in which the at least one compression chamber is fluidly separated from the discharge chamber and from the intake area.

In some embodiments at least one pressure pocket, in particular of the several pressure pockets or of the at least two pressure pockets, is fluidly connected to the at least one compression chamber at least in a time span of the period when the at least one compression chamber is fluidly connected to the intake area.

With respect to further details about the moveable scroll body and the stationary scroll body, in particular about their design and their arrangement, no further details have been given so far.

In particular, the scroll compressor comprises a drive unit for driving the moveable scroll body. In particular, the moveable scroll body is moveable with respect to the stationary scroll body and/or with respect to a housing of the scroll compressor and in particular the drive unit drives the moveable scroll body such that the moveable scroll body is in motion relative to the stationary scroll body and/or to the housing of the scroll compressor.

In particular, the drive unit comprises a shaft and the shaft is rotatably mounted for rotation around a shaft axis.

During the operation of the scroll compressor the shaft rotates around the shaft axis.

In particular, the drive unit drives the moveable scroll body on an orbital path around the shaft axis during operation of the scroll compressor.

For example, the moveable scroll body has a hub and the shaft engages with an eccentric offset drive section the hub for driving the moveable scroll body in particular on an orbital path around the shaft axis.

Preferably, the scroll compressor further comprises a support member which supports the moveable scroll body in axial direction with respect to the shaft axis.

Advantageously, a thrust bearing is formed between the moveable scroll body and the support member.

In particular, the stationary scroll body is at least essentially stationary relative to the housing of the scroll compressor during operation of the scroll compressor.

In particular, during operation of the scroll compressor the stationary scroll body is stationary in radial direction with respect to the shaft axis and/or in a circumferential direction around the shaft axis. For example, an in particular limited and preferably small motion of the stationary scroll body in axial direction is enabled and allowed during operation of the scroll compressor, where the axial direction being in particular with respect to the central axis of the stationary scroll body and/or with respect to the shaft axis.

In preferred embodiments, the central axis of the stationary scroll body and the shaft axis are at least approximately aligned to each other and in particular fall essentially on a common axis.

In particular, a central axis of the movable scroll body is in radial direction offset to the central axis of the stationary scroll body and to the shaft axis.

In particular, the central axis of the stationary scroll body and the shaft axis are at least approximately parallel to each other.

In particular, the central axis of the stationary scroll body and the central axis of the moveable scroll body are at least approximately parallel to each other.

In particular, the central axis of the moveable scroll body and the shaft axis are at least approximately parallel to each other.

Preferably, the scroll compressor further comprises a holding assembly for holding the stationary scroll body, in particular for keeping the stationary scroll body stationary during operation of the scroll compressor.

In particular, the holding assembly prevents a motion of the stationary scroll body in at least one of a radial direction and/or a rotational direction with respect to their central axis of the stationary scroll body and/or with respect to the shaft axis. Preferably, an axial movement with respect to the central axis of the stationary scroll body and/or with respect to the shaft axis is in one direction limited by the holding assembly for the stationary scroll body, in particular by an abutment surface provided by the holding assembly.

In particular, an axial movement of the stationary scroll body with respect to the central axis of the stationary scroll body and/or with respect to the central axis of the moveable scroll body and/or with respect to the shaft axis is limited in one direction by the moveable scroll body.

In particular, the axial movement of the stationary scroll body with respect to the central axis of the stationary scroll body and/or with respect to the central axis of the moveable scroll body and/or with respect to the shaft axis is in one direction limited by the moveable scroll body and in the opposite direction by the holding assembly.

Advantageously, due to the allowance of an in particular limited axial movement of the stationary scroll body the stationary scroll body is enabled to adapt its arrangement relative to the moveable scroll body to the varying different pressures of the gaseous medium contained in the at least one compression chamber during a compression cycle such that a motion of the moveable scroll body relative to the stationary scroll body is smoother.

In particular, the moveable scroll body and the stationary scroll body are part of a compression unit of the scroll compressor.

In particular, the compression unit receives from the intake area a gaseous medium at the suction pressure and compresses the gaseous medium to a higher pressure than the suction pressure, in particular to a maximal intermediate pressure, and discharges the compressed gaseous medium to the discharge chamber. At the discharge chamber the gaseous medium is at the discharge pressure. Depending on the embodiments, the maximal intermediate pressure can be larger than or smaller than or equal to the discharge pressure, for example as discussed above.

Further details concerning the discharge chamber have not been given so far.

In particular, at least a portion of the discharge chamber, to which in the following it is also referred to as the first portion of the discharge chamber, is arranged at the first side of the stationary scroll body and is in particular surrounded in radial direction with respect to the central axis of the stationary scroll body by the scroll wrap of the stationary scroll body and/or is surrounded in radial direction with respect to the central axis of the stationary scroll body and/or with respect to the central axis of the moveable scroll body by the scroll wrap of the moveable scroll body.

In particular, the spiral space formed between the scroll wrap of the stationary scroll body opens at its radially inner end into the discharge chamber, in particular in the portion of the discharge chamber arranged at the first side of the stationary scroll body, and the radially inner end being in particular a radially inner end with respect to the radial direction with respect to the central axis of the stationary scroll body.

In particular, the discharge chamber has at least a portion, to which in the following it is also referred to as the second portion, which is arranged at the second side of the stationary scroll body.

In particular, the base plate of the stationary scroll body has a discharge breakthrough which fluidly connects the first portion and the second portion of the discharge chamber.

Preferably, a seal arrangement, in particular the seal arrangement described above, fluidly separates the discharge chamber in particular at the second side of the stationary scroll body from a low pressure environment around the stationary scroll body.

In particular, the discharge chamber is fluidly connected to an outlet port of the scroll compressor.

In preferred embodiments, in the fluid connection between the discharge chamber and the outlet port an outlet chamber is arranged in the housing of the scroll compressor.

Preferably, between the discharge chamber and the outlet chamber a check valve is arranged and in particular the check valve controls the discharge process and prevents high pressure gas in the outlet chamber to flow back into the discharge chamber.

In advantageous embodiments, the check valve is arranged in the seal arrangement.

The outlet port is arranged with respect to the flow of the gaseous medium downstream the discharge chamber.

Above and in the following, features which are described to be provided in particular, for example, advantageously, preferably and the like are optional features which are not essential for the invention but for example provide advantageous improvements.

Before and in the following values or directions or positions and the like which are provided "at least approximately" are to be understood that deviations therefrom which are technically conditioned and/or technically irrelevant are comprised by the at least approximately provided value, direction, position and the like. For example, deviations by at least approximately provided entities up to ± 10 %, preferably up to ± 5 %, in particular up to ± 1 % are comprised. For example, directions which deviate up to 20°, preferably up to 10°, in particular up to 5°, for example up to 1° are comprised by an at least approximately provided direction.

In particular, advantageous embodiments of the invention comprise the combination of features as defined by the following consecutively numbered embodiments.

1. A scroll compressor (110), the scroll compressor (110) comprises two scroll bodies (192, 194), one of the two scroll bodies (192,194) is a stationary scroll body (192) with a scroll wrap (226) and the other scroll body of the two scroll bodies (192, 194) is a moveable scroll body (192) with a scroll wrap (228), the scroll wraps (226, 228) of the two scroll bodies (192, 194) engage each other forming at least one compression chamber (232), and the stationary scroll body (192) comprises a base plate (212) and the stationary scroll body (192) has two opposing sides (222, 344) with respect to the base plate (212) and on a first side (222) of the two opposing sides (222, 344) the scroll wrap (226) of the stationary scroll body (192) is arranged and on a second side (344) of the two opposing sides (222, 344) at least one pressure pocket (426) is formed and at least one vent passage (452) is provided through the base plate (212) from the first side (222) to the second side (344), the vent passage (452) opens at the second side (344) into the at least one pressure pocket (426) and the vent passage (452) has an opening (454) at the first side (222) which is arranged such that the vent passage (452) is fluidly connected to the at least one compression chamber (232) during a compression cycle of the at least one compression chamber (232) at least during a time span before the at least one compression chamber (232) is fluidly connected to a discharge chamber (138) of the scroll compressor (110) and at least during a time span of the period when the at least one compression chamber (232) is fluidly connected to the discharge chamber (138).

2. A scroll compressor, in particular in accordance with embodiment 1, the scroll compressor (110) comprises two scroll bodies (192, 194), one of the two scroll bodies (192,194) is a stationary scroll body (192) with a scroll wrap (226) and the other scroll body of the two scroll bodies (192, 194) is a moveable scroll body (192) with a scroll wrap (228), the scroll wraps (226, 228) of the two scroll bodies (192, 194) engage each other forming at least one compression chamber (232), and the stationary scroll body comprises a base plate (212) and has two opposing sides (222, 344) with respect to the base plate (212) and on a first side (222) of the two opposing sides (222, 344) the scroll wrap (226) of the stationary scroll body (192) is arranged and on a second side (344) of the two opposing sides (222, 344) one pressure pocket (426) is formed or several pressure pockets (426) are formed and for each pressure pocket (426) at least one vent passage (452) is provided through the base plate (212) from the first side (222) to the second side (344), each vent passage (452) opens at the second side (344) into the respective pressure pocket (426) and each vent passage (452) has an opening (454) at the first side (222) which is arranged such that the vent passage (452) is fluidly connected to the at least one compression chamber at least during a time span during a respective compression cycle and in the one pressure pocket (426) or in the several pressure pockets (426) gaseous medium is contained and at least during operation of the scroll compressor (110) due to a pressure of the gaseous medium a force is exerted on the stationary scroll body (192), in particular in axial direction with respect to a central axis (246) of the stationary scroll body (192), and the force exerted by the pressure of the gaseous medium in the one pressure pocket (426) or in the several pressure pockets (426) is dependent on a suction pressure (PS) at which the gaseous medium enters the at least one compression chamber (232) at the very beginning of the respective compression cycle and on a discharge pressure (PD) which a gaseous medium in a discharge chamber (138) of the scroll compressor (110) has.

3. The scroll compressor (110) according to one of the preceding embodiments, wherein at least one pressure pocket (426) is during a compression cycle fluidly connected to at least one compression chamber (232) of a pair of compression chambers (232), in particular is fluidly connected to exactly one compression chamber (232) or both compression chambers (232) of a pair of compression chambers (232).

4. The scroll compressor (110) according to one of the preceding embodiments, wherein during a compression cycle of the at least one compression chamber the two scroll bodies (192, 194) are arranged in several different configurations to each other, the several different configurations impose different conditions on the at least one compression chamber (232), the different conditions comprise a first condition in which the at least one compression chamber (232) is fluidly connected to an intake area (136) and the different conditions comprise a second condition in which the at least one compression chamber (232) is fluidly separated from the intake area (136) and the discharge chamber (138) and the different conditions comprise a third condition in which the at least one compression chamber (232) is fluidly connected to the discharge chamber (138) and the opening (454) of the vent passage (452) is arranged at the first side (222) such that the vent passage (452) is fluidly connected to the at least one compression chamber (232) in at least one configuration of the two scroll bodies (192, 194) in which the second condition is imposed on the at least one compression chamber (232) and in at least one configuration of the two scroll bodies (192, 194) in which the third condition is imposed on the at least one compression chamber (232). 5. The scroll compressor (110) according to one of the preceding embodiments, wherein the opening (454) of the vent passage (452) at the first side (222) of the stationary scroll body (192) is arranged such that it opens into the at least one compression chamber (232) during the compression cycle of the at least one compression chamber (232) at least during a time span when the gaseous medium in the at least one compression chamber (232) has a pressure which depends on the suction pressure (PS) and on the course of the compression cycle but not on the discharge pressure (PD).

6. The scroll compressor (110) according to one of the preceding embodiments, wherein the opening (454) of the vent passage (452) at the first side (222) of the stationary scroll body (192) is arranged such that it opens into the at least one compression chamber (232) during the compression cycle of the at least one compression chamber (232) at least during a time span when the gaseous medium in the at least one compression chamber (232) is at the discharge pressure.

7. The scroll compressor (110) according to one of the preceding embodiments, wherein the pressure pocket (426) and the vent passage (452) are designed such that during operation of the scroll compressor (110) at least one of a lowest pressure and/or an averaged pressure of the gaseous medium in the pressure pocket (426) during a compression cycle equals to or is larger than 75 % of the discharge pressure (PD).

8. The scroll compressor (110) according to one of the preceding embodiments, wherein the one pressure pocket (426) and the one vent passage (452) or the several pressure pockets (426) and the respective vent passages (452) are designed such that during operation of the scroll compressor (110) a force exerted on the stationary scroll body (192) by the gaseous medium within the one pressure pocket (426) or within at least one pressure pocket (426) and/or a total force exerted by the gaseous medium contained in the several pressure pockets (426) equals to or is larger than a minimal force exerted by the gaseous medium contained in the at least one compression chamber (232) during a respective compression cycle and/or equals to or is smaller than one and a half times a maximal force exerted by the gaseous medium within the at least one compression chamber during a respective compression cycle with the force exerted by the gaseous medium in the at least one compression chamber is exerted on the stationary scroll body (192).

9. The scroll compressor (110) according to one of the preceding embodiments, wherein the vent passage (452) allows exchange of gaseous medium between the at least one compression chamber (262) and the pressure pocket (426) when they are fluidly connected but in particular the vent passage (426) is sufficiently small to prevent an instantaneous pressure balance between the at least one compression chamber (232) and the pressure pocket (426) when the pressure pocket (426) and the at least one compression chamber (232) are fluidly connected by the vent passage (452).

10. The scroll compressor (110) according to one of the preceding embodiments, wherein the pressure pocket (426) is formed partly by the stationary scroll body (192) and partly by a closing element (422) which is fluid tight connected to the part of the stationary scroll body (192) which partly forms the pressure pocket (426). 11. The scroll compressor (110) according to the preceding embodiment, wherein the closing element (422) and the stationary scroll body (192) are fluid tight connected by a floating seal arrangement.

12. The scroll compressor (110) according to one of the preceding embodiments, wherein a portion (394) of the base plate (212) of the stationary scroll body partly limits the pressure pocket (426).

13. The scroll compressor (110) according to one of the preceding embodiments, wherein an inner ridge (382) and an outer ridge (384) each of which surround a central axis (246) of the stationary scroll body (192) are arranged at the second side of the stationary scroll body (192) and project from the base plate (212) of the stationary scroll body (192) and the pressure pocket (426) is arranged in radial direction of the central axis (246) of the stationary scroll body (192) between the inner ridge (382) and the outer ridge (384).

14. The scroll compressor (110) according to the preceding embodiment, wherein the closing element (422) is arranged in radial direction of the central axis (246) of the stationary scroll body (192) between the inner ridge (382) and the outer ridge (384) for limiting the pressure pocket (426).

15. The scroll compressor (110) according to one of the preceding embodiments, wherein the closing element (422) limits the pressure pocket (426) in the axial direction with respect to the central axis (246) of the stationary scroll body (192) opposite to the base plate (212) of the stationary scroll body (192). 16. A scroll compressor (110), for example according to one of the preceding embodiments, the scroll compressor (110) comprises two scroll bodies (192, 194), one of the two scroll bodies (192,194) is a stationary scroll body (192) with a scroll wrap (226) and the other scroll body of the two scroll bodies (192, 194) is a moveable scroll body (192) with a scroll wrap (228), the scroll wraps (226, 228) of the two scroll bodies (192, 194) engage each other to form at least one compression chamber (232) and the stationary scroll body (192) comprises a base plate (212) and has two opposing sides (222, 344) with respect to the base plate (212) and on a first side (222) of the two opposing sides (222, 344) the scroll wrap (226) of the stationary scroll body (192) is arranged and on the second side (344) of the two opposing sides (222, 344) at least two pressure pockets (426) are formed and each of the at least two pressure pockets (426) is connected to at least one respective vent passage (452) and the vent passages (452) are formed through the base plate (212) of the stationary scroll body (192) from the second side (344) at which they open into their respective pressure pocket (426) to the first side (222) at which each vent passage (452) has an opening (454) which is arranged to fluidly connect the respective pressure pocket (426) with the at least one compression chamber (232) in a time span during the compression cycle of the at least one compression chamber (232).

17. The scroll compressor (110) according to one of the preceding embodiments, wherein at least two pressure pockets (426) are fluidly connected to the at least one compression chamber (232) during different time spans during a compression cycle.

18. The scroll compressor (110) according to one of the preceding embodiments, wherein the scroll compressor (110) further comprises a drive unit (122) for driving the moveable scroll body (194), in particular for driving the moveable scroll body (194) relative to the stationary scroll body (192) and/or relative to a housing (112) of the scroll compressor (110). 19. The scroll compressor according to one of the preceding embodiments, wherein the scroll compressor (110) comprises a support member (196) which supports the moveable scroll body (194) in axial direction with respect to a shaft axis (154) of a shaft (152) of the drive unit (122).

20. The scroll compressor (110) according to one of the preceding embodiments, the scroll compressor (110) further comprising a holding assembly (312) which prevents a motion of the stationary scroll body (192) in at least one of a radial direction and/or a rotational direction with respect to the central axis (246) of the stationary scroll body (192).

21. The scroll compressor (110) according to one of the preceding embodiments, wherein an axial movement of the stationary scroll body (192) with respect to the central axis (246) of the stationary scroll body (192) is in one direction limited by the moveable scroll body (194) and in the opposite direction by a holding assembly (312) for the stationary scroll body (192).

22. The scroll compressor (110) according to one of the preceding embodiments, wherein the stationary scroll body (192) and the moveable scroll body (194) are parts of a compression unit (120) of the scroll compressor (110) and the compression unit (120) receives from the intake area (136) the gaseous medium at a suction pressure (PS) and compresses the gaseous medium to a higher pressure than the suction pressure (PS), in particular to a maximal intermediate pressure (PF), and discharges the compressed gaseous medium to the discharge chamber (138) in which the gaseous medium is at a discharge pressure (PD).

23. The scroll compressor (110) according to one of the preceding embodiments, wherein at least a portion (434) of the discharge chamber (138) is arranged at the first side (222) of the stationary scroll body and is in particular surrounded in radial direction with respect to the central axis (246) of the stationary scroll body (194) by the scroll wrap (226) of the stationary scroll body (192) and the scroll wrap (228) of the moveable scroll body (194). Further, preferred features and advantages of the invention are the subject of the detailed specification below and the representation in the drawing of exemplary embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

Fig. 1 shows a cross section through an embodiment of a scroll compressor; fig. 2 shows a partially enlarged view of the scroll compressor shown in fig. 1 in an area with a compression unit and an engaging drive shaft; fig. 3 shows a partially even more enlarged view in an area of a stationary scroll body and a separator plate and a seal arrangement; fig. 4 shows a partially even more enlarged view in an area of the stationary scroll body with a pressure pocket; fig. 5 shows a schematic view of engaging scroll wraps forming several compression chambers and one compression chamber being in fluid contact with an intake area and one compression chamber being fluidly separated from an intake area and a discharge chamber; fig. 6 shows a schematic view of engaging scroll wraps forming several compression chambers and one compression chamber is in fluid connection with a discharge chamber; fig. 7 shows a diagram showing the evolution of the pressure in a compression chamber during a compression cycle and a time span in which the pressure pocket is fluidly connected to the respective compression chamber; fig. 8 a diagram similar as in fig. 7 of variant of the embodiment; fig. 9 shows a view similar to the one in fig. 2 of another embodiment of a scroll compressor; fig. 10 shows a view similar to the one in fig. 3 of the other embodiment; fig. 11 shows a view similar to the one of fig. 4 of the other embodiment.

DETAILED DESCRIPTION OF THE INVENTION

An embodiment of a compressor assembly with at least one scroll compressor 110 is exemplarily discussed in connection with figs. 1 to 6.

The scroll compressor 110 comprises a compressor housing 112 with an inlet port 114 and an outlet port 116 for a gaseous medium and in the interior of the compressor housing 112 a fluid path for the gaseous medium from the inlet port 114 to the outlet port 116 is defined, as exemplarily shown in fig. 1.

In particular, the gaseous medium is a refrigerant and for example the gaseous medium is a working fluid of a cooling circuit and/or a working fluid of a circuit of a heat pump.

Within the fluid path a compression unit which is designated in its entirety with 120 is provided for compressing the refrigerant from a low pressure state as provided to the inlet port 114 to a high pressure state provided to the outlet port 116 and the compression unit 120 is driven by a drive unit 122 of the compressor 110. The gaseous medium is provided along the fluid path, in particular along the drive unit 122, to an intake area 136 at the compression unit 120, in which the gaseous medium is compressed, and the compressed gaseous medium in the high pressure state is provided to an discharge chamber 138 which is connected to the outlet port 116.

Preferably, between the discharge chamber 138 and the outlet port 116 an outlet chamber 142 is provided and a check valve 144 in between controls the discharge process and prevents high pressure gas in the outlet chamber 142 to flow back into the discharge chamber 138.

The drive unit 122 comprises a shaft 152 for driving the compression unit 120. The shaft 152 is rotatably mounted for rotation around a shaft axis 154 for example in an upper bearing support 156 and a lower bearing support 158 which are fixed in the compressor housing 112.

In particular, the lower bearing support 158 is positioned with respect to a direction 162 of gravity below the upper bearing support 156 in an operational state of the compressor 110.

In particular, the upper bearing support 156 is arranged between the compression unit 120 and the drive unit 122.

Preferably, the lower bearing support 158 is provided between the drive unit 122 and a bottom 174 of the compressor housing 112.

Preferably, the drive unit 122 comprises a stator 166 for example with electrical coils and which is fixed to the compressor housing 112 and a rotor 168 within the stator 166 and which is fixed, for example press fitted, glued, keyed or shrinked, to the shaft 152. During operation the stator 166 and the rotor 168 operably work together to rotate the rotor 168 and together with the rotor 168 the shaft 152 around the shaft axis 154.

In particular, a lubricant sump 172 is provided at the bottom 174 of the housing 112 with the bottom 174 being at a lower end of the housing 112 with respect to the direction 162 of gravitation in an operational state of the compressor 110.

The shaft 152 extends into the lubricant sump 172 with an input section 176.

Within the shaft 152 a lubricant passage way 178 is formed which connects the input section 176 with an output opening 182 at the other axial end of the shaft 152 opposite to the input section 176.

In particular, the lubricant passage way 178 is inclined with respect to the shaft axis 154.

The compression unit 120 comprises two compression bodies which are designed as scroll bodies 192, 194, as exemplarily shown for example in fig. 1 and 2, one of which, here the scroll body 192 is stationary relative to the compressor housing 112 and the other scroll body, here scroll body 194, is moveable relative to the stationary scroll body 192 and accordingly moveable relative to the compressor housing 112.

The two scroll bodies engage each other and work operably together for compressing the gaseous medium, in particular the refrigerant.

For movably mounting of the moveable scroll body 194, a support member 196 is provided for supporting the moveable scroll body 194. The support member 196 provides in particular a thrust bearing 198 for the moveable scroll body 194. The support member 196 is fixed within the compressor housing 112 and in particular is mounted to or is a part of the upper bearing support 156.

The stationary scroll body 192 is mounted in the compressor housing 112 as will be described below.

Each of the scroll bodies 192, 194 have a respective base plate 212, 214, which extend mostly in respective geometrical base planes 216, 218, which are arranged at least approximately parallel to each other and at least approximately perpendicular to the shaft axis 154.

In particular, the base plates 212, 214 have an extension within the respective base plane 216, 218 which are much larger, for example at least five times larger, preferably at least ten times larger, as an extension of the respective base plate 212, 214 perpendicular to the respective base plane 216, 218.

On a first side 222 of the stationary scroll body 192 a scroll wrap 226 is arranged which projects at least approximately perpendicular away from the base plate 212 of the stationary scroll body 192 and the scroll wrap 226 is designed in the form of a spiral.

On a first side 224 of the moveable scroll body 194 a scroll wrap 228 is arranged which projects at least approximately perpendicular away from the base plate 214 of the moveable scroll body 194 and the scroll wrap 228 is designed in the form of a spiral.

Both scroll bodies 192, 194 are arranged such that their first sides 222 and 224 face each other and the scroll wraps 226 and 228 engage in one another and form at least one compression chamber 232, preferably several compression chambers 232, between the scroll wraps 226, 228 and the base plates 212, 214 as exemplarily shown in figs. 1 and 2. Advantageously, the scroll wraps 226, 228 have at their axial end facing away from the respective base plate 212, 214 sealing elements 236 and 238, respectively, which abut sealingly against the base plate 214, 212 of the other scroll body 194, 192, for sealingly closing the at least one compression chamber 232 or the several compression chambers 232.

The scroll bodies 192, 194 are arranged to each other, such that the moveable scroll body 194 is mounted moveable with its central axis 244 around a central axis 246 of the stationary scroll body 192 on an orbital path.

Upon orbiting rotation of the moveable scroll body 194 in a rotation direction a compression chamber 232 undergoes a compression cycle.

At the beginning of the compression cycle the compression chamber 232 is open at a radially outer periphery of the stationary scroll body 194 in fluid contact with the intake area 136 such that the gaseous medium in the low pressure state enters in the compression chamber 232 and upon progressive orbiting rotation the compression chamber 232 moves along the spiral form of the scroll wraps 226, 228 and radially inward and thereby its volume decreases and the contained gaseous medium gets compressed and ultimately at a radially inner region the compression chamber 232 is fluidly connected to the discharge chamber 138 to which the compressed gaseous medium in its high pressure state is discharged.

In particular, from the discharge chamber 138 the gaseous medium in the high pressure state is provided to the outlet port 116 through valve 144 and outlet chamber 142. For the orbiting movement of the moveable scroll body 194, the moveable scroll body 194 has a hub 256 at a second side 258 which is, in particular in the axial direction of the central axis 244 of the scroll body 194, opposite to its first side 224, and the drive shaft 152 engages in the hub 256 with an eccentric offset drive section 262 which is provided at an axial end of the drive shaft 152 facing towards the moveable scroll body 194.

The eccentric offset drive section 262 is for example an axial eccentric extension of the drive shaft 152 with a smaller diameter than the main part of the drive shaft 152 and being at least approximately cylindrical around an offset axis 276.

The offset axis 276 is distanced but parallel to the axis 154 of shaft 152 and in a mounted state the offset axis 276 is at least approximately concentric with the central axis 244 of the moveable scroll body 194 and the axis of the receiving portion 264.

In variants of the embodiment the eccentric offset drive section 262 is a bearing pin offset to the shaft axis 154 and in the mounted state at least approximately concentric with the central axis 244 of the moveable scroll body 194.

The eccentric offset drive section 262 is rotatably engaged in the hub 256 and therefore upon rotation of the drive shaft 152 around its shaft axis 154 the axis 276 of the drive section 262 performs an orbital movement around the shaft axis 154 and drives the moveable scroll body 194 along its orbital movement with the central axis 244 of the moveable scroll body 194 orbiting along the orbital path.

In particular, the moveable scroll body 194 is coupled to a coupling which prevents a rotary motion of the moveable scroll body 194 around its central axis 244 and/or around the axis 276 of the drive section 262. Preferably, the coupling restricts the motion of the moveable scroll body 194 to linear motions along to two axes which are perpendicular to each other and the two axes are perpendicular to the axis 276 of the drive section 262.

Therewith, the orbiting motion of the moveable scroll body 194 is as a superposition of the linear motions along the two axes possible, but a rotary motion around the axis 276 of the drive section 262 is prevented.

For example, the coupling is an Oldham coupling known in the prior art.

The lubricant passage way 178 extends through the drive section 262 until its very axial end at which the output opening 182 is provided and opens into a receiving chamber formed in the hub 256.

Therewith, lubricant can be provided from the lubricant sump 172 to the hub 256 through the lubricant passageway 178 for lubrication in particular between the hub 256 and the drive section 262, and for example for lubrication of the thrust bearing 198 and/or of other parts of the scroll compressor 110 in the housing 112.

For mounting the stationary scroll body 192 in the compressor housing 112 and for keeping the stationary scroll body 192 essentially stationary during a compression cycle, a holding assembly is provided which is designated with 312 in its entirety and exemplarily shown in fig. 2.

In particular, the holding assembly 312 comprises a pilot ring 314 which encircles the stationary scroll body 192 such that an inner cylindrical surface 316 of the pilot ring 314 abuts an outer cylindrical surface 318 of the stationary scroll body 192 wherein with respect to the central axis 246 of the stationary scroll body 192 the inner cylindrical surface 316 is directed radially inwards and the outer cylindrical surface 318 is directed radially outwards. Therewith, a movement of the stationary scroll body 192 in the radial direction with respect to its central axis 246 is constrained. In particular, an outer cylindrical wall 322 of the stationary scroll body 192 forms the outer cylindrical surface 318.

Preferably, the stationary scroll body 192 has a flange portion 324 which projects from the outer cylindrical wall 322 in the radial direction of the central axis 246 of the stationary scroll body 192 beyond the outer cylindrical surface 318 and provides an axially directed abutment surface 326 which abuts at least in an abutment position an axial surface 328 of the pilot ring 314 with respect to the axial direction of the central axis 246 of the stationary scroll body 192.

The pilot ring 314 is arranged such that when the abutment surface 326 of the flange portion 324 abuts the axial surface 328 of the pilot ring 314 a movement of the stationary scroll body 192 in axial direction with respect to the central axis 246 of the stationary scroll body 192 is limited.

In particular, the pilot ring 314 and the stationary scroll body 192 further engage such that a rotary movement of the stationary scroll body 192 around its central axis 246 is prevented.

For example, the stationary scroll body 192 has several projecting edges each of which engages with a respective slot of the pilot ring to constrain a rotation of the stationary scroll body 192 around its central axis 146.

Furthermore, the holding assembly 312 comprises a floating seal arrangement designated in its entirety with 332 and is exemplarily shown in fig. 3.

The floating seal arrangement 332 seals the discharge chamber 138 from a low pressure environment 336 around the stationary scroll body 192. The seal arrangement 332 comprises a seal member 342 which is in fluid tight connection with the compressor housing 112 and a second side 344 of the stationary scroll body 192.

The second side 344 of the stationary scroll body 192 is opposite to the first side 222 of the stationary scroll body 192 with respect to the central axis 246 of the stationary scroll body 192.

For example, a separator plate 346 is arranged between the outlet chamber 142 and the low pressure environment 336 and the separator plate 346 limits together with an upper portion 348 of the compressor housing 112 the outlet chamber 142 with the outlet port 116 being arranged in the upper portion 348 of the compressor housing 112.

The separator plate 346 has a peripheral portion 352 at which it is fluid tight connected to the compressor housing 112.

The separator plate 346 has in an inner part an orifice 354 by which the discharge chamber 138 is connected with the outlet chamber 142.

The seal member 342 is, in particular with a circular ledge 356 in connection with a rim portion 358 of the separator plate 346 which surrounds the orifice 354.

For example, the ledge 356 abuts directly the rim portion 358 or preferably a gasket 362 is arranged between the ledge 356 and the rim portion 358.

The connection between the seal member 342 and the separator plate 346 is at least during operation of the compressor 110 fluid tight as will be described in detail below. The seal member 342 has at least one hole 366 which provides a fluid passage for the compressed gaseous medium from the discharge chamber 138 to the orifice 354 and further to the outlet chamber 142.

In particular, the seal member 342 comprises a disc portion 368 in which the at least one hole 366 is arranged and the ledge 356 is arranged at a periphery of the disc portion 368 at a side which faces towards the separator plate 346.

The fluid tight connection between the seal member 342 and the separator plate 346 surrounds the at least one hole 366.

Preferably, the check valve 144 is arranged at the seal member 342 and allows flow of compressed gaseous medium from the discharge chamber 138 through the hole 366 towards the orifice 354 and further to the outlet chamber 142 but prevents backflow from the outlet chamber 142 to the discharge chamber 138.

For example, the check valve comprises a rod 372 and a valve disc 374.

The rod 372 is fixed at one end to the disc portion 368 and extends towards the outlet chamber 142 to a second end at which it has an abutment flange 376.

The valve disc 374 is slidingly arranged at the rod 372 to be moveable between the disc portion 368 and the abutment flange 376.

The valve disc 374 is sized to cover the at least one hole 366 and in case of several holes to cover each hole of the several holes when the valve disc 374 is aligned at the seal member 342. In particular, the rod 372 extends through the orifice 354 and the valve disc 374 is sized to be small enough to be able to pass through the orifice 354 when being pushed from the compressed gaseous medium which flows from the discharge chamber 138 to the outlet chamber 142.

A backflow from the outlet chamber 142 to the discharge chamber 138 is prevented by the valve disc 374 because a respective pressure difference causes a closing force to the valve, in particular a backflow takes the valve disc 374 and pushes it against the seal member 342 such that the at least one hole 366 is covered.

The stationary scroll body 192 has an inner ridge 382 and an outer ridge 384 which are arranged at the second side 344 on the base plate 212 and project in axial direction of the central axis 246 of the stationary scroll body 192 from the base plate 212 away in direction towards the separator plate 346.

Preferably, the inner ridge 382 and the outer ridge 384 have each a circular shape with the respective circular shapes being concentric to each other and the center of the circular shapes are located on the central axis 246 of the stationary scroll body 192.

The inner ridge 382 has a radially outer side 386 and the outer ridge 384 has a radially inner side 388 with the outer radially side 386 and the inner radially side 388 facing each other in the radial direction of the central axis 246 of the stationary scroll body 192.

For example, the radially outer side 386 of the inner ridge 382 has at least partly a cylindrical surface facing towards the radially inner side 388 of the outer ridge 384 and the radially inner side 388 of the outer ridge 384 has at least partly a cylindrical surface which faces towards the radially outer side 386 of the inner ridge 382. Therewith, an in particular at least essentially ring-like shaped hollow space 392 is formed at the second side 344 of the stationary scroll body 192 with the hollow space 392 being limited in radial direction by the outer side 386 of the inner ridge 382 und the inner side 388 of the outer ridge 384 and in axial direction by an in particular at least essentially ring-like shaped portion 394 of the base plate 212 and the radial and axial direction being with respect to the central axis 246 of the stationary scroll body 192.

The hollow space 392 has an opening 396 which is arranged between the inner ridge 382 and the outer ridge 384 with respect to the radial direction of the central axis 246 of the stationary scroll body 192 and is opposite to the portion 394 of the base plate 212 with respect to the axial direction of the central axis 246 of the stationary scroll body 192 and in particular the radially outer side 386 of the inner ridge 382 surrounds at an radially inner side the opening 396 and the radially inner side 388 of the outer ridge 384 surrounds the opening 396 at a radially outer side.

The seal member 342 engages with an engaging portion 412 into the hollow space 392 and an outer seal 414 is arranged between the engaging portion 412 and the inner side 388 of the outer ridge 384 and an inner seal 416 is arranged between the engaging portion 412 and the outer side 386 of the inner ridge 382 such that a cavity 418 is formed which is limited by the engaging portion 412 and parts of the inner ridge 382 and of the outer ridge 384 and the portion 394 of the base plate 212 of the stationary scroll body 192.

The cavity 418 is fluidly separated from the low pressure environment 336 by the outer seal 414 and fluidly separated from the discharge chamber 138 by the inner seal 416. The engaging portion 412 therefore forms a closing element 422 for the cavity 418.

For example, a with respect to the central axis 246 radially outer side of the engaging portion 412 which faces towards the outer ridge 384 has a recess in which a sealing ring providing the outer seal 414 is arranged.

For example, a groove is formed at the radially outer side 386 of the inner ridge 382 in which a sealing ring is arranged for providing the inner seal 416.

In variants of the embodiment it is provided that a recess is formed in the engaging portion 412 at a side facing towards the inner ridge 382 in which a sealing ring is arranged for providing the inner seal 416 and/or a groove is formed in the inner side 388 of the outer ridge 384 in which a sealing ring is arranged for providing the outer seal 414.

The inner ridge 382 surrounds a discharge breakthrough 432 through the base plate 212 of the stationary scroll body 192 and the discharge breakthrough 432 fluidly connects a first portion 434 and a second portion 436 of the discharge chamber 138.

The second portion 436 of the discharge chamber 138 is arranged at the second side 344 of the stationary scroll body 192 and is at least partly surrounded by the inner ridge 382. The at least one hole 366 in the seal member 342 opens into the second portion 436 of the discharge chamber 138.

The first portion 434 of the discharge chamber 138 is arranged at the first side 222 of the stationary scroll body 192.

The first portion 434 of the discharge chamber 138 is at a radially innermost part at the first side 222 and the scroll wrap 226 of the stationary scroll body 192 is arranged in the radial direction of the central axis 246 around the first portion 434. Both, the spiral space 227 formed by the scroll wrap 226 of the stationary scroll body 192 and the spiral space 229 formed by the scroll wrap 228 of the moveable scroll body 194 open at their respective radial inner end into the first portion 434 of the discharge chamber 138 with the scroll wraps 226, 228 being arranged to surround the first portion 434 of the discharge chamber 138.

At least one vent passage 452 is formed in the stationary scroll body 192 which extends through the base plate 212 from a first opening 454 at the first side 222 which opens into the spiral space 227 to a second opening 456 which opens at the second side 344 into the cavity 418.

In particular, the second opening 456 is arranged in the portion 394 of the base plate 212 which limits the cavity 418 and therefore a pressure pocket 426 is formed, as exemplarily shown in figs. 3 und 4.

The first opening 454 is preferably arranged at the surface of the base plate 212 of the stationary scroll body 192 where its portion limits the spiral space 227 in the axial direction with respect to the central axis 246 of the stationary scroll body 192.

The first opening 454 is arranged such that during a compression circuit of a compression chamber 232 which is formed between the scroll wraps 226, 228 of the stationary scroll body 192 and the moveable scroll body 194 the first opening 454 opens into the compression chamber 232 at least during a time span before the compression chamber 232 is fluidly connected to the discharge chamber 138 and the first opening 454 opens into the compression chamber 232 at least during a time span when the compression chamber 232 is fluidly connected to the discharge chamber 138, as exemplarily shown in figs. 5 and 6. Accordingly, during its compression cycle the compression chamber 232 is fluidly connected to the pressure pocket 426 by the vent passage 452 at least during a time span before the compression chamber is fluidly connected to the discharge chamber 138 and at least during a time span of the period in which the compression chamber 232 is fluidly connected to the discharge chamber 138.

In particular, in the time span in which the first opening 454 opens into the compression chamber 232 before the compression chamber 232 is fluidly connected to the discharge chamber 138, the compression chamber 232 is fluidly separated from the intake area 136.

During a compression cycle the two scroll bodies are arranged in several different configurations to each other and form several compression chambers 232, 232', ... in their spiral spaces 227, 229 between the respective scroll wraps 226, 228. During a respective compression cycle the compression chambers 232, 232', ... are in different conditions which are imposed by the scroll bodies 192, 194 in dependence of their configuration relative to each other.

In particular, during a compression cycle two compression chambers 232A, 232B are in at least essentially the same condition. In the following it will be referred to such two compression chambers 232A, 232B also as a pair of compression chambers 232. In particular, the pressures of the gaseous medium in the two compression chambers 232 of a pair of compression chambers 232 are during a compression cycle at least essentially the same.

At the beginning of a compression cycle of a compression chamber, the compression chamber is in fluid connection with the intake area 136 and gaseous medium in the low pressure state enters into the compression chamber, as exemplarily shown in fig. 5 for the compression chambers 232'A and 232'B. In the further course of the compression cycle the compression chamber transitions from the initial first condition to a second condition in which the compression chamber is fluidly separated from the intake area 136 and fluidly separated from the discharge chamber 138, as exemplarily shown in fig. 5 and Fig. 6 for the compression chambers 232"A, 232"B and the compression chambers 232"'A, 232"'B which are even more progressed in the course of the compression cycle.

In particular, in the second condition the compression chamber 232, 232', ... is entirely limited by the stationary scroll body 192 and the moveable scroll body 194, in particular by their respective scroll wraps 226, 228 and their respective base plates 212, 214 and the sealing elements 236, 238 seal between the stationary scroll body 192 and the moveable scroll body 194.

During the part of the course of the compression cycle in which the compression chamber 232 is in the second condition, the compression chamber 232 moves along the spiral form of the scroll wraps 226, 228 radially inwards due to the changing configurations of the moveable scroll body 194 relative to the stationary scroll body 192. During this course the volume of the compression chamber 232 decreases and the gaseous medium therein gets compressed and accordingly its pressure P rises.

Finally, in a final third condition during the compression cycle, the compression chamber reaches the radial innermost part of the spiral form of the scroll wraps 226, 228 and gets fluidly connected to the first portion 434 of the discharge chamber 138, as exemplarily shown in fig. 6 for the compression chambers 232""A, 232""B.

In this third condition the pressure P in the compression chamber equals a discharge pressure PD of the compression unit 120. The pressure P in a compression chamber during the compression cycle is also exemplarily sketched in fig. 7.

During a first period SI the compression chamber is in the first condition and the gaseous medium within the compression chamber is at a pressure P which equals the suction pressure PS. At a point in time T1 due to the orbiting motion of the moveable scroll body 194 the condition of the compression chamber changes to the second condition and during the period S2 the compression chamber is in this second condition and the pressure P of the confined gaseous medium within the compression chamber 232 rises.

At a point in time T2 the condition of the compression chamber 232 changes from the second condition to the third condition in which the compression chamber 232, 232', ... is in fluid connection with the discharge chamber 138 and accordingly the gaseous medium in the compression chamber is at a discharge pressure PD for the final period S3 of the compression cycle.

At the very end of the period S2, that is right before the point in time T2 when the compression chamber 232 opens to the discharge chamber 138 the pressure P of the gaseous medium within the compression chamber equals to a maximal intermediate pressure PF.

In the variant sketched in fig. 7 the maximal intermediate pressure PF equals the discharge pressure PD.

In other variants of the embodiment a discharge pressure PD', PD" differs from the maximal intermediate pressure PF, for example the discharge pressure PD' is larger than the maximal intermediate pressure PF or the discharge pressure PD" is smaller than the maximal intermediate pressure PF, as exemplarily shown in fig. 8. The value of the discharge pressure PD, PD', PD" depends on a variety of factors, for example among others on the state in which the scroll compressor 110 is operated, in particular at which pressure ratio the scroll compressor 110 is operated, under circumstances of a system in which the scroll compressor 110 is operated, for example circumstances downstream the outlet port 116.

The first opening 454 is arranged such that during a compression cycle it opens to the compression chamber 232 during a time span SO which comprises a first time span SOI when the compression chamber 232 is in the second condition and the time span SO comprises a second time span SO2 in which the compression chamber 232 is in the third condition.

Accordingly, the first opening 454 opens at a point in time TO1 during the second period S2 of the compression cycle into the compression chamber 232 and from this point in time TO1 the first time span SOI of the time span SO in which the compression chamber 232 is fluidly connected to the pressure pocket 426 through the vent passage 452 starts.

At the point in time T2 the compression chamber opens to the discharge chamber 138 and the second period S2 of the compression cycle in which the compression chamber is in the second condition ends and also the first part SOI of the time span SO in which the first opening 454 opens into the compression chamber ends and the third period S3 of the compression cycle in which the compression chamber is in fluid connection to the discharge chamber 138 starts and the second part SO2 of the time span SO in which the first opening 454 opens to the compression chamber starts.

In some embodiments the first opening 454 is arranged such that it opens to the compression chamber 232 until the end of the compression cycle that is until the end of the period S3 and in other variants of the embodiment the first opening 454 is arranged such that the time span SO in which the first opening 454 opens to the compression chamber 232 ends before the compression cycle and the third period S3 end. In some variants there are two similarly arranged first openings 454A, 454B of two respective vent passages 452 each of which opens into a respective compression chamber 232A, 232B of a pair of compression chambers 232, as exemplarily shown in figs. 5 and 6.

In other variants there is only one fist opening 454 of a respective vent passage 452 which opens into a respective compression chamber 232, in particular in one compression chamber 232 of a pair of compression chambers 232. For example, there is only one of the two first openings 454A, 454B exemplarily shown in figs. 5 and 6. In particular, a first opening 454 which is arranged to open during a compression cycle in one compression chamber 232A of a pair of compression chambers 232 is arranged such that during the compression cycle it does not open into the other compression chamber 232B of the pair of compression chambers 232. For example, this can be achieved by arranging this first opening 454, in particular at the base plate 212 of the stationary scroll body 192, such that when the other compression chamber 232 passes by the first opening 454 this first opening 454 is covered by the scroll wrap 228 of the moveable scroll body 194, in particular covered by the sealing element 238 at the scroll wrap 228.

The pressure P of the gaseous medium in the compression chamber 232 during the second period S2 of the compression cycle and during the first part SOI of the time span SO in which the first opening 454 opens to the compression chamber depends on the suction pressure PS and the location of the compression chamber 232 along the spiral form of the scroll bodies 226, 228, that is in particular on the course of time of the compression cycle.

In the third period S3 and accordingly in the second part SO2 of the time span SO in which the first opening 454 opens into the compression chamber 232 the pressure P of the gaseous medium in the compression chamber 232 equals the discharge pressure PD, PD', PD" and is in particular independent of the suction pressure PS. Accordingly, the pressure pocket 426 is in connection with compression chamber 232 during a time span SOI when the pressure P of the gaseous medium in the compression chamber is higher than the suction pressure PS and the pressure P of the gaseous medium in the compression chamber depends on the suction pressure PS and also during a time span SO2 when the pressure P of the gaseous medium in the compression chamber is the discharge pressure PD, PD', PD".

Therewith, the pressure pocket 426 is filled with gaseous medium and the gaseous medium in the pressure pocket 426 has during operation of the scroll compressor 110 a pressure P which for example varies between a lowest pressure PL and a highest pressure PH with the highest pressure PH being larger than the lowest pressure PL.

In particular, the lowest pressure PL and the highest pressure PH are larger than a pressure PO1 which is the pressure of the gaseous medium in the compression chamber at the point in time TO1 at which for the first time the first opening 454 opens to the compression chamber 232, that is at the beginning of the time span SO and accordingly at the beginning of the first part SOI of the time span SO.

In particular, the lowest pressure PL and the highest pressure PH are smaller than the maximal intermediate pressure PF of the gaseous medium in the compression chamber 232 at the point in time T2 when the compression chamber transitions from the second to the third condition and/or are smaller than the discharge pressure PD, PD', PD". In particular, the vent passage 452 is designed such that a sufficient exchange of gaseous medium between the compression chamber 232 and the pressure pocket 426 is possible, when they are fluidly connected, but on the other hand the vent passage 452 is sufficiently small so that even if there is a fluid connection between the compression chamber 232 and the pressure pocket 426 there is no essentially instantaneous pressure balance between the gaseous medium contained in the pressure pocket 426 on the one hand and the gaseous medium in the fluidly connected compression chamber 232 on the other hand.

Therewith, preferably the pressure P of the gaseous medium contained in the pressure pocket 426 gets averaged over the compression cycles but still may vary between a lowest pressure PL and a highest pressure PH the values of which are in particular between the pressures PO1 and the larger one of the maximal intermediate pressure PF and the discharge pressure PD, PD'.

For example, design of the vent passage 452 and of the pressure pocket 426 are such that at least the highest pressure PH is during operation of the scroll compressor 110 the same as or larger than 75 % of the discharged pressure PD, PD', PD" and/or the same as or larger than 75 % of the maximal intermediate pressure PF. In some preferred variants of embodiment the design of the vent passage 452 and of the pressure pocket 426 is such that the lowest pressure PL is the same or larger than 75 % of the discharge pressure PD, PD', PD" and/or is the same or larger than 75 % of the maximal intermediate pressure PF.

With the pressure establishing in the pressure pocket 426 the seal member 342 is pressed away from the stationary scroll body 192 in direction towards the separator plate 346 and against the separator plate 346 such that the ledge 356 is pressed against the separator plate 346 with for example the gasket 362 in between and they are fluid tight connected. Due to the pressure of the gaseous medium in the pressure pocket 426 a force is exerted on the stationary scroll body 192 towards the moveable scroll body 194 and which acts against the force exerted by the compressed gaseous medium in the pressure chamber 232.

In particular, briefly summarizing, the compressor 110 works as follows and has for example the following advantages.

Through the inlet port 114 a gaseous medium, in particular a refrigerant is provided along the fluid path to the compression unit 120 in a low pressure state and the compression unit 120 is driven by the drive unit 122 and compresses the gaseous medium and provides it in a high pressure state along the fluid part to the outlet port 116. For example, the gaseous medium is guided along the fluid path through and/or around the drive unit 122 and advantageously the gaseous medium cools thereby the drive unit 122.

For compressing the gaseous medium, the compression unit 120 comprises the stationary scroll body 192 and the moveable scroll body 194 which engage with their respective scroll wraps 226, 228 to form at least one compression chamber 232 . The moveable scroll body 194 is driven by the drive unit 122 in particular by the eccentric offset drive section 262 of the shaft 152, on an orbital path and due to this orbital movement of the moveable scroll body 194 the volume of the at least one compression chamber 232 decreases during a respective compression cycle and the gaseous medium in the respective compression chamber 232 is compressed.

At the beginning of a respective compression cycle, the compression chamber 232 is in a first condition in which it is fluidly connected to the intake area 136 and gaseous medium at the suction pressure PS enters the compression chamber 232 . In the further course of the compression cycle, the compression chamber 232 is in a second condition in which it is fluidly separated from the intake area 136 and from the discharge chamber 138 and its volume decreases and accordingly the pressure P of the gaseous medium in the compression chamber rises up to the maximal intermediate pressure PF.

The compression chamber 232 moves during the course of the compression cycle radially inwards along the spiral form of the scroll wraps 226, 228.

At the end of the compression cycle, the compression chamber 232 is in a third condition in which it is in fluid connection with the discharge chamber 138 and the gaseous medium exits the compression chamber 232 into the discharge chamber 138 where it has the discharge pressure PD, PD', PD".

The gaseous medium leaves the discharge chamber 138 in particular through the check valve 144 and through the outlet chamber 142 towards the outlet port 116.

At the second side 344 of the stationary scroll body 192 at least one pressure pocket 426 is formed in particular by the cavity 418 with the second side 344 being with respect to the axial direction of the central axis 246 of the stationary scroll body 192 opposite to the first side 222 of the stationary scroll body 192 on which the scroll wrap 226 of the stationary scroll body 192 is arranged.

The pressure pocket 426 is fluidly connected by at least one vent passage 452 to the spiral space 227 between the scroll wrap 226 of the stationary scroll body 192. The first opening 454 of the vent passage 452 opens at the first side 222 of the stationary scroll body 192 into the spiral space 227 and is arranged such that during a respective compression cycle of a compression chamber 232 the pressure pocket 426 is fluidly connected to the compression chamber 232 at least during the time span SOI when the compression chamber 232 is fluidly separated from the intake area 136 and fluidly separated from the discharge chamber 138 and such that the pressure pocket 426 is fluidly connected to the compression chamber 232 as well during the time span SO2 when the compression chamber 232 is fluidly connected to the discharge chamber 138 and the gaseous medium in the compression chamber 232 is at the discharge pressure PD, PD', PD".

Therewith, the pressure pocket 426 is exposed to gaseous medium in the compression chamber 232 which has pressures P which are larger than the suction pressure PS and reach the maximal intermediate pressure PF as well as to gaseous medium at the discharge pressure PD, PD', PD".

Therefore, the gaseous medium in the pressure pocket 426 has a pressure which depends on the suction pressure PS, the discharge pressure PD, PD', PD" and the configuration between the stationary scroll body 192 and the moveable scroll body 194 and in particular the course of the compression cycle of the compression chamber 232 to which the pressure pocket 426 is fluidly connected at a specific point in time.

Preferably, the gaseous medium in the pressure pocket 426 has an approximately averaged pressure which depends on various factors, for example the ones mentioned above. In particular, the averaged pressure of the gaseous medium in the pressure pocket 426 varies during a compression cycle, for example between the lowest pressure PL and the highest pressure PH. Whereas advantageously, due to the in particular varying and for example averaged pressure of the gaseous medium in the pressure pocket 426, a force is exerted on the stationary scroll body 192 which acts against the force exerted by the gaseous medium which is compressed in the compression chamber 232 and which forces the stationary scroll body 192 away from the moveable scroll body 194.

Because the pressure of the gaseous medium in the pressure pocket 426 depends on both, the suction pressure PS and the discharge pressure PD, PD', PD", and in particular on the course of the compression cycle of the compression chamber 232, the force exerted by the gaseous medium in the pressure pocket 426 mimics similarly the behavior of the force exerted by the compressed gaseous medium in the compression chamber 232 and therefore advantageously a more consistent load between the scroll bodies 192, 194 is achieved. For example, the force between the scroll bodies 192, 194 where the respective scroll wrap 226, 228 is in connection with the base plate 214, 212 of the other scroll body 194, 192, for example in indirect connection through the sealing elements 236, 238, is more consistent throughout a compression cycle and during operation of the scroll compressor.

Preferably, the pressure pocket 426, in particular the portion 394 of the base plate 212 of the stationary scroll body 192 which limits the pressure pocket 426 and/or the closing element 422, which in this embodiment is formed by the engaging portion 412 of the seal member 342, and/or other parts of the stationary scroll body 192, for example the inner ridge 382 and/or the outer ridge 384, which also limit the pressure pocket 426, are designed such that during operation of the scroll compressor 110 the force exerted by the gaseous medium in the pressure pocket 426 is optimized for a mostly consistent load between the scroll bodies 192, 194 and an optimized operation of the compression unit 120. For example, the force exerted by the gaseous medium in the pressure pocket 426 is larger than the smallest force exerted by the gaseous medium in the compression chamber 232 during a respective compression cycle and smaller than one and a half times the largest force exerted by the compressed gaseous medium in a compression chamber 232 during a compression cycle.

In particular, due to the pressure of the gaseous medium in the pressure pocket 426 the seal member 342 is pressed towards the separator plate 346 and therefore a fluid tight connection at the seal arrangement 332 is obtained in particular for fluidly separating the outlet chamber 142 from the low pressure environment 336 which is around the stationary scroll body 192.

In connection with another embodiment, which is exemplarily and partly shown in figs. 9 to 11, elements and features which are at least essentially the same and/or fulfill at least the same basic function as one element and/or feature of the above described embodiment are designated with the same reference sign and concerning the description of these elements and/or features it is referred to the specification given above unless in the following an alternative arrangement and/or design of these elements and/or features is provided. In particular, when an alternative arrangement and/or design is to be emphasized, a suffix "a" designating this embodiment will be attached to the respective reference sign.

The scroll compressor 110 of this embodiment has a compression unit 120 with a stationary scroll body 192 and a moveable scroll body 194 which have scroll wraps 226, 228 which engage each other to form one compression chamber 232 preferably several compression chambers 232 for compression of a gaseous medium.

At a beginning of a compression cycle, a respective compression chamber 232 opens to an intake area 136 and receives gaseous medium at a suction pressure PS. In the further course of the compression cycle the compression chamber 232 moves radially inwards along the spiral form of the scroll wraps 226, 228 and gets separated from the intake area 136 such that the compression chamber 232 as is fluidly separated from the intake area 136 and the discharge chamber 138 referred to above as the second condition and during this period S2 of the compression cycle the volume of the compression chamber 232 decreases and the contained gaseous medium is compressed and its pressure increases up to a maximal intermediate pressure PF at the end of this period S2.

At an end of the compression cycle, the compression chamber 232 opens to the discharge chamber 138 in a period S3 of the compression cycle which follows the period S2, and the gaseous medium in the compression chamber 232 is at the discharge pressure PD, PD', PD". The compressed gaseous medium flows out of the compression chamber 232 to the discharge chamber 138 and in particular through a check valve 144 and an outlet chamber 142 to an outlet port 116 of the scroll compressor 110.

In this embodiment there are two pressure pockets 426al and 426aII arranged on a second side 344 of the stationary scroll body 192 with the second side 344 being with respect to an axial direction of a central axis 246 of the stationary scroll body 192 opposite to a first side 222 of the stationary scroll body 192.

On the first side 222 of the stationary scroll body 192 the scroll wrap 226 of the stationary scroll body 192 is arranged.

A base plate 212 of the stationary scroll body 192 is arranged between the first side 222 and the second side 344 of the stationary scroll body 192. Each of the pressure pockets 426al, 426aII is formed by the stationary scroll body 192 and a respective closing element 422al and 422aII.

The closing element 422al is in fluid tight connection with a part of the stationary scroll body 192 which limits the pressure pocket 426al to form the pressure pocket 422al and the other closing element 422aII is in fluid tight connection with a part of the stationary scroll body 192 which limits the other pressure pocket 426aII to form this pressure pocket 426aII.

In particular, the stationary scroll body 192 has an inner ridge 382 and an outer ridge 384 and an intermediate ridge 472 with these ridges 382, 384, 472 being arranged on the second side 344 of the stationary scroll body 192 and being attached to the base plate 212 of the stationary scroll body 192 and projecting away from the base plate 212 in particular essentially in axial direction of the central axis 246 of the stationary scroll body 192 and/or in direction towards a separator plate 346.

The inner ridge 382, the outer ridge 384 and the intermediate ridge 472 have for example each a respective essentially circular shape with the circular shapes being concentric to each other and the center of the circular shapes being arranged on the central axis 246 of the stationary scroll body 192.

In particular, the direction in which the ridges 382, 384, 472 project away from the base plate 212 of the stationary scroll body 192 is at least approximately perpendicular to a geometrical plane in which the ridges 382, 384, 472 have the essentially circular shape.

The inner ridge 382 has an outer side 386 which faces in the radial direction of the central axis 246 of the stationary scroll body 192 towards the intermediate ridge 472 and the intermediate ridge 472 has an inner side 474 facing in the radial direction of the central axis 246 of the stationary scroll body 192 towards the inner ridge 382 and is opposite to the outer side 386 of the inner ridge 382. In particular, the inner ridge 382 has at its outer side 386 at least partly a cylindrical surface and/or the intermediate ridge 472 has at its inner side 474 at least partly a cylindrical surface with the cylindrical surfaces of the inner ridge 382 and of the intermediate ridge 472 at its inner side 474 facing each other.

Between the inner ridge 382 and the intermediate ridge 472 a hollow space 392al is formed which in the radial direction is in between and limited by the outer side 386 of the inner ridge 382 and the inner side 474 of the intermediate ridge 472 and is limited in an axial direction by a portion 394al of the base plate 212 of the stationary scroll body 192 which in particular extends between the inner ridge 382 and the intermediate ridge 472 in the radial direction and with the radial and axial direction being with respect to the central axis 246 of the stationary scroll body 192.

The hollow space 392al between the inner ridge 382 and the intermediate ridge 472 has an opening 396al which in axial direction with respect to the central axis 246 of the stationary scroll body 192 is opposite to the portion 392al of the base plate 212 limiting the hollow space 392 and the opening 396al being in particular surrounded by the inner ridge 382 radially on the inside and radially on the outside by the intermediate ridge 472, with the radial and axial direction being with respect to the central axis 246 of the stationary scroll body 192.

The intermediate ridge 472 has an outer side 476 which is in the radial direction opposite to the inner side 474 of the intermediate ridge 472 and faces towards the outer ridge 384. The outer ridge 384 has an inner side 388 which in radial direction faces towards the outer side 476 of the intermediate ridge 472 and the radial direction being with respect to the central axis 246 of the stationary scroll body 192. In between the intermediate ridge 472 and the outer ridge 384 a hollow space 392aII is formed. In particular, the hollow space 392aII is limited in radial direction by the outer side 476 of the intermediate ridge 472 and by the inner side 388 of the outer ridge 384 and in axial direction by a portion 394aII of the base plate 212 of the stationary scroll body 192 with a radial and axial direction being with respect to the central axis 246 of the stationary scroll body 192. In particular, the portion 392aII limiting axially the hollow space 392aII between the intermediate ridge 472 and the outer ridge 384 extends between the intermediate ridge 472 and the outer ridge 384.

The hollow space 392aII between the intermediate ridge 472 and the outer ridge 384 has an opening 396aII which is in axial direction with respect to the central axis 246 of the stationary scroll body 192 opposite to the portion 394aII of the base plate 212 limiting the hollow space 392aII and the opening 396aII is surrounded radially on the inside by the intermediate ridge 472 and radially on the outside by the outer ridge 384 with the radial direction being with respect to the central axis 246 of the stationary scroll body 192.

A seal member 342a engages with an engaging portion 412al in the hollow space 392al between the inner ridge 382 and the intermediate ridge 472 and with another engaging portion 412aII into the hollow space 392aII between the intermediate ridge 472 and the outer ridge 384 and the engaging portions 412al and 412aII are in particular connected to each other by a connection portion 482 of the seal member 342a. In particular, the connecting portion 482 extends in radial direction over the intermediate ridge 472 and has an axially directed surface facing towards the intermediate ridge 472 with a radial and axial direction being with respect to the central axis 246 of the stationary scroll body 192.

There is provided an inner seal 416 which seals between the inner ridge 382 and the engaging portion 412al which engages in the hollow spaces 392al between the inner ridge 382 and the intermediate ridge 472. There is provided an outer seal 414 which seals between the outer ridge 384 and the engaging portion 412aII which engages in the hollow space 392aII between the outer ridge 384 and the intermediate ridge 472.

There is provided an intermediate seal 484 which seals between the intermediate ridge 472 and the entirety of the two engaging portions 412al and 412aII and the connecting portion 482 connecting these two engaging portions 412al, 412aII.

For example, the intermediate seal 484 seals between the intermediate ridge 472 and the engaging portion 412aII which engages in the hollow space 292aII, as exemplarily shown in fig. 11. In other variants of the embodiment the intermediate seal 484 seals between the intermediate ridge 472 and the connecting portion 482. In other variants of embodiment the intermediate seal 484 seals between the intermediate ridge 472 and the engaging portion 412al which engages in the hollow space 292al between the inner ridge 382 und the intermediate ridge 472.

Therewith, a cavity 418al between the inner ridge 282 and the intermediate ridge 472 and a cavity 418aII between the intermediate ridge 472 and the outer ridge 384 are formed which are sealingly separated by the intermediate seal 484 and are limited by respective parts of the stationary scroll body 192 and of the seal member 342a, in particular by the respective portions 392al, 392aII of the base plate 212 and by portions of the respective ridges 382, 384, 472 as parts of the stationary scroll body 192 and by the respective engaging portion 412al, 412aII and if applicable by the connecting portion 482 as parts of the seal member 342a.

The cavity 418al forms the pressure pocket 426al which is connected by a second opening 456al to a vent passage 452al which extends through the base plate 212 of the stationary scroll body 192 and opens with a first opening 454al into the spiral space 227 between the scroll wrap 226 of the stationary scroll body 192. In particular, the second opening 456 of the vent passage 452al opens into the pressure pocket 426al between the inner ridge 382 and the intermediate ridge 472.

In particular, the first opening 454al of the vent passage 452al, which is fluidly connected to the pressure pocket 426al between the inner ridge 382 and the intermediate ridge 472, is arranged in accordance with the embodiment described above, that is this first opening 454al opens to a compression chamber 232 during a compression cycle at least during a time span before the compression chamber 232 is fluidly connected to the discharge chamber 138 and at least during a time span when the compression chamber 232 is fluidly connected to the discharge chamber 138. In particular the first opening 454al opens during a compression cycle into the compression chamber 232 in a time span SO and during a first part SOI of the time span SO the compression chamber 232 is in the second condition and during a second part SO2 of the time span SO the compression chamber 232 is in the third condition.

In other variants of the embodiment the first opening 454al of the vent passage 452al which is fluidly connected to the pressure pocket 426al between the inner ridge 382 and the intermediate ridge 472 is arranged such that this first opening 454al opens into a compression chamber 232 during its compression cycle only when the compression chamber 232 is fluidly connected to the discharge chamber 138, that is, when the compression chamber 232 is in the third condition.

In this variant of the embodiment, the pressure of a gaseous medium in the pressure pocket 426al between the inner ridge 382 and the intermediate ridge 472 is at least approximately the discharge pressure P of the gaseous medium in the discharge chamber 138. In other variants of the embodiment, the first opening 454al of the vent passage 452al which is fluidly connected to the pressure pocket 426 between the inner ridge 382 and the intermediate ridge 472 is arranged such that this first opening 454 opens into the compression chamber 232 during its compression cycle only in a time span when the compression chamber 232 is in its second condition that is when it is fluidly separated from the intake area 136 and fluidly separated from the discharge chamber 138.

In these variants of the embodiment the pressure P of the gaseous medium in the pressure pocket 426al between the inner ridge 382 and the intermediate ridge 472 is dependent on the suction pressure PS, the arrangement of the corresponding first opening 454al which is fluidly connected by the vent passage 452al to this pressure pocket 426al and the time dependent evolution of the pressure of the gaseous medium in the compression chamber 232 but not on the discharge pressure PD, PD', PD"..

In particular, the pressure P of the gaseous medium in the pressure pocket 426al between the inner ridge 382 and the intermediate ridge 472 in these variants of the embodiment is an averaged pressure of the various pressures of the gaseous medium in the compression chamber 232 which occur when the pressure pocket 426al is fluidly connected to the compression chamber 232.

In particular, the averaged pressure varies with time between a lowest pressure PLal and a highest pressure PHal which is larger than the lowest pressure PLal and the lowest pressure PLal and the highest pressure PHal being larger than the suction pressure PS and for example smaller than the maximal intermediate pressure PF of the gaseous medium in the compression chamber 232 at the end of the period S2 in which the compression chamber 232 is in the second condition. The pressure pocket 426aII between the intermediate ridge 472 and the outer ridge 384 is fluidly connected to a vent passage 452aII which extends through the base plate 212 of the stationary scroll body 192 and opens with a first opening 454aII into the spiral space 227 between the scroll wrap 226 of the stationary scroll body 192 and opens with a second opening 456aII into the cavity 418aII between the intermediate ridge 472 and the outer ridge 384 and accordingly also opens into the pressure pocket 426aII formed by that cavity 418aII.

In particular the second opening 456aII which opens into the cavity 418aII between the intermediate ridge 472 and the outer ridge 384 is arranged in the portion 394aII of the base plate 212 of the stationary scroll body 192 which extends between the intermediate ridge 472 and the outer ridge 384.

The first opening 454aII which is connected by the respective vent passage 452aII to the pressure pocket 426aII between the intermediate ridge 472 and the outer ridge 384 is in particular arranged such that during a compression cycle of a respective compression chamber 232 this first opening 454aII opens into that compression chamber 232 partly during the period S2 in which that compression chamber 232 is in the second condition that is, it is fluidly separated from the intake area 136 and from the discharge chamber 138. Accordingly, the pressure of the gaseous medium in the pressure pocket 426aII between the intermediate ridge 472 and the outer ridge 384 is dependent on the suction pressure PS and the time evolution of the pressure of the gaseous medium in the compression chamber 232 but not on the discharge pressure PD, PD', PD".

In particular, the pressure of the gaseous medium in the pressure pocket 426aII between the intermediate ridge 472 and the outer ridge 384 is an average pressure of the various pressures of the gaseous medium in the compression chamber 232 during the time span SO in which this compression chamber 232 is fluidly connected to that pressure pocket 426aII and in particular this averaged pressure varies with time between a lowest pressure PLall and a highest pressure PHall with the highest pressure PHall being larger than the lowest pressure PLall and for example the lower and highest pressures PLall, PHall are between the suction pressure PS and the maximal intermediate pressure PF of the gaseous medium in the compression chamber 232 at the end of the period S2 in which the compression chamber 232 is in the second condition.

In particular, during a compression cycle of a compression chamber 232 the pressure pocket 426aII between the intermediate ridge 472 and the outer ridge 384 is connected to that compression chamber 232 before the pressure pocket 426al between the inner ridge 382 and the intermediate ridge 472 is connected to that compression chamber 232 and therefore the pressure of the gaseous medium in the pressure pocket 426aII between the intermediate ridge 472 and the outer ridge 384 is lower than the pressure in the pressure pocket 426al between the inner ridge 382 and the intermediate ridge 472.

In particular, the lowest pressure PLall of the gaseous medium in the pressure pocket 426aII between the intermediate ridge 472 and the outer ridge 384 is smaller than the lowest pressure PLal of the gaseous medium in the pressure pocket 426al between the inner ridge 382 and the intermediate ridge 472.

In particular, the highest pressure PHall of the gaseous medium in the pressure pocket 426aII between the intermediate ridge 472 and the outer ridge 384 is smaller than the highest pressure PHall of the gaseous medium in the pressure pocket 426al between the inner ridge 382 and the intermediate ridge 472.

In variants of the embodiment the first opening 454aII of the vent passage 452aII which is fluidly connected to the pressure pocket 426aII between the intermediate ridge 472 and the outer ridge 384 is arranged such that it opens into a compression chamber 232 during a time span at the beginning of the compression cycle when the compression chamber 232 is still in fluid contact with the intake area 136 and therefore the gaseous medium in the compression chamber 232 is at the suction pressure PS. For example, during a time span when that first opening 454aII opens into the compression chamber 232 this compression chamber 232 transitions from the first condition to the second condition that is it gets fluidly separated from the intake area 126 and the pressure of the contained gaseous medium rises.

In other variants of the embodiment the first opening 454aII of the vent passage 452aII which is fluidly connected to the pressure pocket 426aII between the intermediate ridge 472 and the outer ridge 384 opens into a compression chamber 232 during its compression cycle only in the first time span SI in which the compression chamber 232 is in fluid connection with the intake area 136 and accordingly that first opening 454aII and the respective pressure pocket 426aII between the intermediate ridge 472 and the outer ridge 384 are in fluid contact to the compression chamber 232 only when the gaseous medium in the compression chamber 232 is at the suction pressure PS and accordingly in that pressure pocket the gaseous medium is essentially also at the suction pressure for these variants of the embodiment.

In particular, the three above described variants of the embodiment with respect to the arrangement of the first opening 454aII of the vent passage 452aII which is fluidly connected to the pressure pocket 426aII between the intermediate ridge 472 and the outer ridge 384 is in different variants of the embodiment combined with one of the three above described variants of the embodiment with respect to the arrangement of the first opening 454al of the vent passage 452al which is in fluid connection with the pressure pocket 426al between the inner ridge 382 and the intermediate ridge 472.

Similarly as described above in connection with the first embodiment, depending on the variant there is for example exactly one respective first opening 454 and/or two first openings 454. In some variants there are two first openings 454al which are fluidly connected to the pressure pocket 426al between the inner ridge 382 and the intermediate ridge 472 and in particular each of the two first openings 454al opens during a compression cycle into a respective compression chamber 232 of a pair of compression chambers 232.

In some variants there is exactly one first opening 454al of one vent passage 452al which is fluidly connected to the pressure pocket 426al between the inner ridge 382 and the intermediate ridge 472 and in particular this one first opening 454al opens during a compression cycle into one compression chamber 232A, 232B of a pair of compression chambers 232.

In some variants there are two first openings 454aII of two respective vent passages 452aII which are fluidly connected to the pressure pocket 426aII between the intermediate ridge 472 and the outer ridge 384 and in particular each of the two first openings 454aII opens during a compression cycle into a respective compression chamber 232 of a pair of compression chambers 232.

In some variants there is exactly one first opening 454aII of one vent passage 452aII which is fluidly connected to the pressure pocket 426aII between the intermediate ridge 472 and the outer ridge 384 and in particular this one first opening 454aII opens during a compression cycle into one compression chamber 232 of a pair of compression chambers 232.

For example, an advantage of this embodiment is that two pressure pockets 426al and 426aII are provided and in particular with the arrangement of the respective first openings 454al and 454aII and/or the designs of the cavities 418al and 418aII which form the pressure pockets 426al and 426aII the in particular varying averaged pressures of the gaseous medium in these pressure pockets 426al, 426aII can be adjusted and the respective forces acting on the stationary scroll body 192 can be adapted as appropriate for a smooth and proper operation of the compression unit 120 and in particular for achieving more consistent load between the moveable scroll body 194 and the stationary scroll body 192.

In other respects the compressor of this embodiment and its functioning is for example at least partly, preferably at least essentially, the same as for the scroll compressor 110 of the first embodiment described above, such that reference is fully made to the explanations provided above, in particular with respect to the design and advantageous features of the in particular floating seal arrangement 332 and/or the seal member 342 and/or the holding assembly 312 for the stationary scroll body 192 and/or the moveable scroll body 194 and in particular the drive section 262 of the shaft 152 engaging with the hub 256 of the moveable scroll body 194 and/or the orbiting motion of the moveable scroll body 194 and/or the fluid path for the gaseous medium to the compressor housing.

RE FERENCE N UM E RA LS scroll compressor compressor housing inlet port outlet port compression unit drive unit intake area discharge chamber outlet chamber check valve shaft shaft axis upper bearing support lower bearing support direction of gravitation stator rotor lubricant sump bottom of housing input section lubricant passage way output opening stationary scroll body moveable scroll body end section of compressor housing support member thrust bearing base plate of stationary scroll body base plate of moveable scroll body base plane base plane first side of stationary scroll body first side of moveable scroll body scroll wrap of stationary scroll body spiral space scroll wrap of moveable scroll body spiral space compression chamber sealing element sealing element central axis of moveable scroll body central axis of stationary scroll body hub second side of moveable scroll body eccentric offset drive section axis of drive section holding assembly pilot ring inner cylindrical surface of pilot ring outer cylindrical surface cylindrical wall flange portion abutment surface of flange portion axial surface of pilot ring seal arrangement low pressure environment seal member second side of stationary scroll body separator plate upper portion of housing peripheral portion orifice ledge rim portion gasket hole disc portion rod valve disc abutment flange inner ridge outer ridge outer side inner side hollow space portion of base plate opening of hollow space engaging portion outer seal inner seal cavity closing element pressure pocket discharge breakthrough first portion of discharge chamber second portion of discharge chamber vent passage first opening of vent passage second opening of vent passage intermediate ridge inner side of intermediate ridge outer side of intermediate ridge connecting portion intermediate seal