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Title:
COMPRESSOR COMPRISING A POWER GENERATOR AND A WANKEL TYPE ROTARY MACHINE
Document Type and Number:
WIPO Patent Application WO/2019/102396
Kind Code:
A1
Abstract:
Described is a compressor (1) comprising a power generator (1A) and a rotary volumetric machine (10) of the Wankel type (epitrochoid), which includes: a stator (100), including a rotor housing (11 ) having an inside surface (12A); a rotor (16), connected to the power generator (1A) by a drive shaft (15) rotating about an axis of rotation (R), and rotating in an eccentric fashion with respect to the axis of rotation (R); an intake duct (13A) and an intake port (13A'); a discharge duct (13B) and a discharge port (13B'); a plurality of dynamic seals (18), connected to the rotor (16) and in sliding contact with the inside surface (12A) of the rotor housing (11), the plurality including a first group of apical lips (18A), positioned on a lateral face (16A) of the rotor (16) and made of polymeric material, and a second group of lateral lips (18B), positioned on respective end faces of the rotor (16) and in sliding contact with the inside surface (12A) of the rotor housing (11); a plurality of shaft seals (19), positioned between the drive shaft (15) and the stator (100) for executing a seal between the drive shaft (15) and the rotor housing (11).

Inventors:
GARDELLI, Paolo (Via Omero 3, PARMA, 40123, IT)
ORZI, Andrea (Via D. Alighieri 10, NOCETO, 43015, IT)
CASTAGNETTI, Max (Strada Barilla 17, MONTECCHIO EMILIA, 42027, IT)
Application Number:
IB2018/059231
Publication Date:
May 31, 2019
Filing Date:
November 22, 2018
Export Citation:
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Assignee:
FORNOVO GAS S.R.L. (Via Ponticelli 5-7, TRAVERSETOLO, 43029, IT)
International Classes:
F01C1/22; F01C19/02; F01C19/08
Foreign References:
US6109040A2000-08-29
US4150926A1979-04-24
US3845562A1974-11-05
Attorney, Agent or Firm:
CONTI, Marco (Via di Corticella 87, Bologna, 40128, IT)
Download PDF:
Claims:
CLAIMS

1. A compressor (1 ) comprising a power generator (1 A) and a Wankel type rotary machine (10), wherein the rotary machine (10) includes:

- a stator (100) including a rotor housing (11 ) having an inside surface (12A) which delimits an internal space (12B);

- a rotor (16) connected to the power generator (1 A) by means of a drive shaft (15) which rotates about an axis of rotation (R) and which is configured to rotate in the internal space (12B) of the rotor housing (1 1 ) eccentrically relative to the axis of rotation (R), wherein the rotor (16) includes a lateral face (16A), surrounding the axis of rotation (R), and a first (16B) and a second (16C) end face perpendicular to the axis of rotation (R);

- an intake duct (13A) and an intake port (13A') which are configured to convey a fluid to be compressed into the internal space (12B) of the rotor housing (1 1 );

- a discharge duct (13B) and a discharge port (13B') which are configured to expel the compressed fluid from the internal space (12B) of the rotor housing (1 1 );

- a plurality of dynamic seals (18), connected to the rotor (16) and in sliding contact with the inside surface (12A) of the rotor housing (1 1 ), this plurality including a first group of apical lips (18A) disposed on the lateral face (16A) of the rotor (16) and made of polymeric material;

- a plurality of shaft seals (19), disposed between the drive shaft (15) and the stator (100) to create a seal between the drive shaft (15) and the rotor housing (1 1 ),

characterized in that the plurality of dynamic seals (18) includes a second group of lateral lips (18B) disposed on the first (16B) and second (16C) end faces of the rotor (16) and in sliding contact with the inside surface (12A) of the rotor housing (1 1 ).

2. The compressor (1 ) according to claim 1 , wherein the apical lips (18A) of the first group of apical lips (18A) are made of polymeric material.

3. The compressor (1 ) according to claim 1 or 2, wherein the plurality of dynamic seals (18) includes a group of vertex seals (18C), wherein each vertex seal (18C) is positioned at the intersection between a corresponding apical lip (18A) and a first and a second corresponding lateral lip (18B), wherein the apical lip (18A) and the first and second lateral seals (18B) converge at a corresponding vertex (16") of the rotor (16).

4. The compressor (1 ) according to claim 1 or 2 or 3, wherein the second group of lateral lips (18B) is made of polymeric material.

5. The compressor (1 ) according to any one of the preceding claims, wherein the plurality of shaft seals (19) is made of polymeric material.

6. The compressor (1 ) according to any one of the preceding claims, comprising a group of lateral springs (191 B), each interposed between a respective lateral lip (18B) and the rotor (16), and wherein each lateral spring (191 B) of the group of lateral springs (191 B) is configured to apply an elastic force on the respective lateral lip (18B) along an axial direction, parallel to the axis of rotation (R), to press it against the inside surface (12A) of the rotor housing (1 1 ).

7. The compressor (1 ) according to any one of the preceding claims, comprising a recirculation hole (24A') in communication with the intake duct (13A) and with a recirculation chamber (2V) which is positioned downstream of the second group of lateral lips (18B) to collect a leak fluid and to automatically return the leak fluid to intake.

8. The compressor (1 ) according to any one of the preceding claims, comprising a collection system (20), configured to collect a leak fluid from a position downstream of the second group of lateral lips (18B), and wherein the collection system (20) is configured to convey the fluid outside the compressor.

9. The compressor (1 ) according to claim 8, wherein the collection system (20) comprises a collection chamber (21 ), outside the rotor housing (1 1 ) and connected to a relief duct through a collection duct (24), and wherein the plurality of shaft seals (19) includes at least one internal shaft seal (22A), interposed between the rotor housing (1 1 ) and the collection chamber (21 ), and at least one external shaft seal (22B), interposed between the collection chamber (21 ) and the outside atmosphere.

10. The compressor (1 ) according to any one of the preceding claims, comprising an air refrigeration system.

1 1. The compressor (1 ) according to any one of the preceding claims, comprising a group of apical springs (191 A), each interposed between a respective apical lip (18A) and the rotor (16), and configured to apply an elastic force on the respective apical lip (18A) to press it against the inside surface (12A) of the rotor housing (1 1 ).

12. The compressor (1 ) according to any one of the preceding claims, wherein the rotor (16) comprises at least one ball bearing (17) interposed between the drive shaft (15) and the rotor (16).

13. The compressor according to any one of the preceding claims, comprising an additional rotor housing (1 V) to form a plurality of rotor housings and an additional rotor (16') to form a plurality of rotors.

14. A method for compressing a fluid in a rotary compressor (1 ), comprising the following steps:

- preparing a power generator (1 A) and a Wankel type rotary machine (10) including:

- a stator (100) including a rotor housing (1 1 ) having an inside surface (12A), which delimits an internal space (12B), and a rotor (16) connected to the power generator (1 A) by means of a drive shaft (15) which rotates about an axis of rotation (R);

- conveying a fluid to be compressed to the rotor housing (11 ) by way of an intake duct (13A) and through an intake port (13A');

- drawing compressed fluid from the rotor housing (1 1 ) by way of a discharge duct (13B) and through a discharge port (13B');

- making an apical dynamic seal (F1 ) between the inside surface (12A) of the rotor housing (1 1 ) and a lateral face of the rotor (16), parallel to the axis of rotation (R), by means of a first group of apical lips (18A) made of polymeric material;

- making a shaft seal (F3) between the drive shaft (15) and the rotor housing (1 1 ) by means of a plurality of shaft seals (19);

characterized in that it comprises a step (F2) of lateral dynamic sealing, wherein a second group of lateral lips (18B) disposed on a first (16B) and a second (16C) end face of the rotor (16), perpendicular to the axis of rotation (R) and remaining in sliding contact with the inside surface (12A) of the rotor housing (11 ).

15. The method according to claim 14, wherein the apical lips (18A) of the first group of apical lips (18A) are made of polymeric material.

16. The method according to claim 14 or 15, wherein the step (F2) of lateral dynamic sealing is carried out by the second group of lateral lips (18B) made of polymeric material.

17. The method according to claim 14 or 15 or 16, wherein the step (F3) of making a shaft seal is carried out by the plurality of shaft seals (19) made of polymeric material.

18. The method according to any one of claims 14 to 17, wherein the compressor (1 ) comprises a group of lateral springs (191 B), each interposed between a respective lateral lip (18B) and the rotor (16), and comprising a step of laterally compressing wherein the group of lateral springs (191 B) presses the respective lateral lip (18B) against the inside surface (12A) of the rotor housing (1 1 ).

19. The method according to any one of claims 14 to 18, comprising a step (F4) of recovering in which the compressor (1 ) recovers a leak fluid from a position downstream of the second group of lateral lips (18B) in order to limit fluid leaks to the atmosphere.

20. The method according to claim 19, wherein the step (F4) of recovering comprises a step (F4') of collecting the leak fluid in a collection chamber (21 ) and a step (F4") of expelling the leak fluid into a relief duct through which the leak fluid is conveyed outside the compressor (1 ).

21. The method according to any one of claims 14 to 20, wherein the compressor (1 ) comprises a group of apical springs (191 A), each interposed between a respective apical lip (18A) and the rotor (16), comprising a step of apically compressing wherein each apical spring (191 A) of the group of apical springs (191 A) presses the respective apical lip (18A) against the inside surface (12A) of the rotor housing (1 1 ).

Description:
COMPRESSOR COMPRISING A POWER GENERATOR AND A WANKEL TYPE ROTARY MACHINE

Technical field

This invention relates to a rotary compressor comprising a Wankel type rotary machine. A rotary compressor is a machine designed to convert the rotational kinetic energy of an element into pressure energy of a fluid according to a predetermined compression ratio. The compression ratio is determined by the geometrical characteristics of the compressor.

Background art

A rotary machine of the Wankel type is a known technology in the sector of power generating machines (e.g. internal combustion engines) and power absorbing machines (e.g. compressors or pumps).

A rotary machine of the Wankel type consists of a stator and a rotor. The stator comprises a rotor housing inside of which is housed the rotor. The rotor housing has an epitrochoidal shape. The rotor, equipped with three or more vertices, is, on the other hand, coupled eccentrically on a drive shaft which rotates about an axis of rotation. The rotor rotates eccentrically relative to the axis of rotation. The rotor is coupled to the drive shaft by a connection which allows its rotation, for example a bearing or a bushing, and is synchronized in its motion by a gearing consisting of two gear wheels: the one with inner teeth integral with the rotor, the one with outer teeth integral with the stator.

The rotor, rotating inside the rotor housing, opens and closes intake ports, from which comes the fluid, and discharge ports from which the fluid is discharged. The intake and discharge ports are made on the rotor housing and can be, or not, provided with automatic valves.

A significant problem which has always involved this architecture of rotary machines has been that of the fluid seals in the compression chambers formed between the walls of the rotor housing and the walls of the rotor. More specifically, we can identify a lateral face of the rotor, surrounding the axis of rotation of the drive shaft, which corresponds to a respective lateral wall of the rotor housing and two end faces of the rotor which correspond to respective end faces of the rotor housing.

To keep two chambers isolated from each other it is necessary to have an apical seal, between an apex, or edge, of the rotor and the lateral wall of the rotor housing, and a lateral seal, between each end face of the rotor and the respective end wall of the rotor housing.

Lastly, but no less important, is to guaranteeing the seal between the drive shaft and the stator, at an opening in which the shaft is inserted. This type of seal will be identified with the term“shaft seal”.

In the technical sector of compressors and internal combustion engines there are prior art rotary machines of the Wankel type in which the seals are made with materials which require a good degree of lubrication and therefore, as well as requiring a dedicated lubrication circuit, might create problems of contamination of the fluid to be compressed.

Other documents describe the use of seals made of polymeric material to increase the efficiency of the seals and prevent the use of lubricating oil. Solutions of this kind are described, for example, in patent US2002028151 A1 , in which specific reference is made to the use of polymeric material for the seals described in the invention.

However, patent document US2002028151 A1 comprises, to form to the lateral seal, the presence of a layer of polymeric material applied directly on the end walls of the rotor housing. This solution has limitations in terms of compression the polymeric seal, as well as costs connected to the covering of the stator with suitable material. Moreover, the gradual wear of the polymeric seal will cause a consequent reduction in the friction force which the rotor exerts on each end wall of the rotor housing, considerably reducing the efficiency of the seals with the increase in life of the rotary machine. Patent document US2002028151 A1 , owing to the nature of the lateral seals, has further problems in the control of fluid leaks towards the outside environment which translate not only into efficiency problems but also into environmental problems.

Other examples of rotary machines of the Wankel type are provided in patent documents US6109040, US4150926 and US3845562. However, these machines do not solve the problems linked to the control of fluid leaks towards the outside environment; moreover, these machines require a dedicated lubrication circuit.

Disclosure of the invention

The aim of this invention is to provide a rotary compressor which overcomes the drawbacks of the prior art described above.

This aim is fully achieved by the rotary compressor according to this invention as characterized in the appended claims.

According to one aspect of this description, a compressor comprises a power generator.

According to an embodiment, the compressor comprises a Wankel type rotary machine.

According to an embodiment, the rotary machine comprises a stator. The stator comprises a rotor housing. According to an embodiment, the rotor housing has an epitrochoidal shape. According to an embodiment, the rotor housing may have any other shape which allows the rotor housing to perform its functions.

The rotor housing comprises an inside surface. The inside surface delimits an space inside the rotor housing. According to an embodiment, the rotor housing comprises a lateral wall. According to an embodiment, the rotor housing comprises a first end wall and a second end wall. According to an embodiment, the faces of the lateral wall and the faces of the end walls define the inside surface of the rotor housing.

According to an embodiment, the rotary machine comprises a rotor. According to an embodiment, the rotor is connected to the power generator by means of a drive shaft rotating about an axis of rotation.

According to an embodiment, the rotor is configured for rotating inside the internal space of the rotor housing in an eccentric fashion relative to the axis of rotation.

According to an embodiment, the rotor comprises a lateral face. The lateral face, according to an embodiment, surrounds the axis of rotation. According to an embodiment, the rotor comprises a first and a second dynamic end face. According to an embodiment, the first and second dynamic end face are perpendicular to the axis of rotation.

In the description below, the first and second dynamic end faces are indicated as the two faces which, in the set of claims, are indicated as the first and second end faces of the rotor. It should be noted that, hereafter, the expression first dynamic end face and first end face of the rotor are equivalent and exchangeable. It should be noted that, hereafter, the expression second dynamic end face and second end face of the rotor are equivalent and exchangeable. The desired aim has been to use a different term in the description to clarify and differentiate the end faces of the rotor and the end faces of the stator.

According to an embodiment, the rotary machine comprises an intake duct. According to an embodiment, the rotary machine comprises an intake port. According to an embodiment, the intake duct and the intake port are configured to convey a fluid to be compressed into the internal space of the rotor housing.

According to an embodiment, the intake duct is not necessarily a tubular body but may also be a manifold, in communication with the intake port to which the fluid to be compressed is conveyed through ducts. The intake duct means an element designed to contain the fluid to be compressed which is in communication with the internal space of the rotor housing through the intake port. In other words, according to an embodiment, the intake duct is configured for introducing the fluid to be compressed into an intake chamber. The intake chamber is configured to contain the fluid to be compressed in a zone between the intake duct and the intake port. The intake chamber is open on the internal space of the rotor housing through the intake port.

According to an embodiment, the intake duct comprises two intake branches, each of which ends in a respective intake port. According to an embodiment, the two intake branches end in an intake chamber.

According to an embodiment, the intake port is a hole made on a wall. According to an embodiment, the intake port is a hole made on a wall, adjusted with an automatic intake valve.

According to an embodiment, the rotary machine comprises a discharge duct. According to an embodiment, the rotary machine comprises a discharge port. According to an embodiment, the discharge duct and the discharge port are configured to expel the compressed fluid from the internal space of the rotor housing.

According to an embodiment, the discharge port is a hole made on a wall, adjusted with an automatic discharge valve.

According to an embodiment, the discharge port is a hole made on a wall. According to an embodiment, the rotary machine comprises a plurality of dynamic seals. According to an embodiment, the plurality of dynamic seals is connected to the rotor. According to an embodiment, the dynamic seals of the plurality of dynamic seals are in sliding contact with the inside surface of the rotor housing.

According to an embodiment, the plurality of dynamic seals includes a first group of apical lips. The apical lips are a sub-set of the plurality of dynamic seals. According to an embodiment, the apical lips of the first group of apical lips are positioned on the lateral face. According to an embodiment, the first group of apical lips is made of polymeric material. According to an embodiment, the first group of apical lips is made of other types of materials which allow working without lubrication.

According to an embodiment, the rotary machine comprises a plurality of shaft seals.

According to an embodiment, the shaft seals of the plurality of shaft seals are positioned between the drive shaft and the stator. This allows the plurality of shaft seals to execute a seal between the drive shaft and the rotor housing. More specifically, the shaft seals make it possible to keep the internal space of the rotor housing isolated from the outside environment.

According to an embodiment, the plurality of dynamic seals includes a second group of lateral lips. According to an embodiment, the lateral lips of the second group of lateral lips are positioned on the first and second dynamic end face of the rotor.

According to an embodiment, the lateral lips of the second group of lateral lips are in sliding contact with the inside surface of the rotor housing.

Even though the presence of a seal between the first and second dynamic end face of the rotor and the respective first and second static end face is indispensable, the presence of the second group of lateral lips, positioned on the rotor, allows the efficiency of the dynamic seal to be increased. According to an embodiment, the plurality of dynamic seals comprises a group of vertex seals.

The group of vertex seals is connected with the first group of apical lips and with the group of lateral lips. In other words, each vertex seal of the group of vertex seals is in contact with a respective lateral lip of the second group of lateral lips and with a respective apical lip of the first group of apical lips. The presence of the group of vertex seals makes it possible to complete the isolation of the compression chambers made in the internal space of the rotor housing. According to an embodiment, each vertex seal is positioned in a respective housing situated at a respective vertex of the rotor.

According to an embodiment, the vertex seals are replaced with a superposing and intersection of the first group of apical lips and of the second group of apical lips. According to an embodiment, the second group of lateral lips is made of polymeric material.

This feature makes it possible to obtain a more efficient seal and above all prevent the presence of a lubrication circuit for the dynamic seals. This leads to the following advantages: reduction in costs, ease of assembly, reduction in probability of faults and, therefore, maintenance operations. According to an embodiment, the plurality of dynamic seals is made of PEEK®, filled with different materials.

The filled PEEK® makes it possible to obtain a lower friction coefficient which enables the lubrication of the dynamic seals to be avoided.

According to an embodiment, the plurality of dynamic seals is made of PEEK®.

According to an embodiment, the plurality of shaft seals is made of polymeric material. This feature makes it possible to avoid an oil lubrication circuit throughout the compressor, with the resulting above- mentioned advantages.

According to an embodiment, the plurality of shaft seals is a plurality of lip seals.

According to an embodiment, the plurality of shaft seals is a plurality of lip seals made of NBR (synthetic rubber based on acrylonitrile and butadiene). What is stated above with regard to the composition of the shaft seals does not exclude that the latter can be also made of different materials.

According to an embodiment, the compressor comprises a plurality of bearings positioned outside the rotor housing. According to an embodiment, the plurality of bearings is keyed to the drive shaft.

According to an embodiment, each bearing of the plurality of bearings comprises at least two screening elements, positioned on opposite sides of the bearing along a direction parallel to the axis of rotation. The screening elements mainly prevent the escape of lubricating grease from the space which houses the rolling elements of the bearing and at the same time also avoid the entrance of fluid inside.

According to an embodiment, each housing (that is to say, each bearing) of the plurality of bearings comprises an equalising hole, configured for equalising any pressure of a fluid upstream or downstream of the bearing. In one embodiment, the compressor (rotor) comprises a plurality of lateral springs. According to an embodiment, each lateral spring of the plurality of lateral springs is interposed between a respective lateral lip and the rotor. In other words, an end of the spring is connected to the rotor and another end is connected to the respective lateral lip. According to an embodiment, for each lateral spring of the plurality of lateral springs, the compressor (rotor) comprises a groove configured to house the spring. The rotor has been specified between brackets since nothing excludes that the stator can house the plurality of lateral springs, in particular on each static end face.

According to an embodiment, each lateral spring of the plurality of lateral springs is configured for exerting an elastic force on the respective lateral lip. According to an embodiment, the elastic force is exerted along an axial direction, parallel to the axis of rotation. The force allows each lateral lip to be pressed against the inside surface of the rotor housing. This force becomes essential when the respective lateral lip, subject to wear, reduces in size. In this configuration, since there is no longer contact from the inside surface of the rotor housing, the spring pushes the respective lateral lip until re-establishing the contact, increasing the efficiency of the dynamic seals and overcoming conditions in which the second group of lateral lips might lose contact with the inside surface of the rotor housing following certain operational conditions.

According to an embodiment, the compressor comprises a collection system. According to an embodiment, the collection system is configured for picking up a leak fluid. According to an embodiment, the system is configured for picking up a leak fluid from a position downstream of the lateral lips. According to an embodiment, the collection system is configured for conveying the leak fluid in a relief duct, configured to convey the fluid to the outside of the compressor.

According to an embodiment, the collection system is configured for reintroducing the leak fluid into the intake duct.

According to an embodiment, the collection system is configured for reintroducing the leak fluid into the intake duct, in a position outside the compressor.

According to an embodiment, the plurality of shaft seals comprises an internal shaft seal. According to an embodiment, the plurality of shaft seals comprises an external shaft seal.

The term internal shaft seal means the first shaft seal which a leak fluid, deriving from a leak on a lateral lip, encounters in its escape path up to an outside environment. The term external shaft seal means a second shaft seal of the plurality of shaft seals which are positioned between the internal shaft seal and the outside environment.

According to an embodiment, the collection system comprises a collection chamber.

According to an embodiment, the collection chamber is positioned, along the escape path, between the internal shaft seal and the external shaft seal.

According to another embodiment, the collection chamber is positioned, along the escape path, between the second group of lateral lips and the internal shaft seal.

According to an embodiment, the collection system is configured for collecting a leak fluid loss deriving from a leak detected on a dynamic seal, in particular on a lateral lip of the second group of lateral lips. According to an embodiment, the collection system is configured for collecting the leak fluid after a lateral lip of the second group of lateral lips and before the internal shaft seal of the plurality of shaft seals.

According to an embodiment, the collection system is configured for collecting a leak fluid deriving from a loss detected on the internal shaft seal. According this embodiment, the collection system is configured for collecting the leak fluid after the internal shaft seal and before the external shaft seal, to convey it outside the compressor. More specifically, the collection system is configured for collecting the leak fluid collected in the collection chamber and from here picking it up through a collection duct. The collection duct, according to an embodiment, is connected with the relief duct, configured for conveying the leak fluid outside the compressor. According to an embodiment, the collection system is configured for collecting the leak fluid after the internal shaft seal and before the external shaft seal, for reintroducing it in the intake duct.

According to an embodiment, the compressor comprises a recirculation chamber. The recirculation chamber is configured for collecting the leak fluid, from a position downstream of the second group of the lateral lips (18B). The recirculation chamber is configured for automatically reintroducing a leak fluid into the intake using a recirculation hole, which is open on the recirculation chamber and on the intake duct.

According to an embodiment, the automatic recirculation chamber is delimited by the second group of lateral lips and by the internal shaft seal. According to an embodiment, the recirculation chamber is delimited by two shaft seals of the plurality of shaft seals positioned between the external shaft seal and the second group of lateral lips.

This allows the compressor to recirculate the leak gas without the risk of dispersion into the environment. In effect, if the main function of the collection chamber, which may be the last barrier before the environment, is to expel the gas rapidly avoiding dispersion into the environment (thus, a safety function), the function of the recirculation chamber is to increase the efficiency of the system, recirculating the leaks into the intake.

According to an embodiment, the collection chamber is outside the rotor housing. According to an embodiment, the collection chamber is connected to the intake duct through a collection duct. According to an embodiment, the internal shaft seal is interposed between the rotor housing and the collection chamber. According to an embodiment, the external shaft seal is interposed between the collection chamber and an outside environment.

According to another embodiment, a lateral lip of the plurality of lateral lips is interposed between the rotor housing and the collection chamber. According to an embodiment, the internal shaft seal is interposed between the collection chamber and the outside environment.

These features allow the rotary machine and, therefore, the compressor to considerably reduce the emissions of gas into the outside environment, with considerable advantages in terms of efficiency and reduction of environmental pollution.

According to an embodiment, the compressor comprises an air refrigeration system.

According to an embodiment, the compressor (rotor) comprises a plurality of apical springs. According to an embodiment, each apical spring of the plurality of apical springs is interposed between a respective apical lip and the rotor. According to an embodiment, each apical spring of the plurality of apical springs is configured for exerting an elastic force on the respective apical lip. This makes it possible to increase the effectiveness of the apical seal, pressing it against the inside surface of the rotor housing, and overcoming conditions in which the first group of apical lips might lose contact with the inside surface of the rotor housing following certain operational conditions.

According to an embodiment, the rotor comprises at least one ball bearing interposed between the drive shaft and the rotor. According to an embodiment, the rotor comprises a bushing interposed between the drive shaft and the rotor.

According to an embodiment, the ball bearing is fixed with a threaded ring nut.

According to an embodiment, the rotary machine comprises a plurality of compression stages. According to an embodiment, the rotary machine comprises an additional rotor housing to form a plurality of rotor housings. According to an embodiment, the rotary machine comprises an additional rotor to form a plurality of rotors. According to an embodiment, the rotary machine comprises an additional eccentric profile, on the drive shaft, to form a plurality of eccentric profiles.

According to an embodiment, each rotor housing of the plurality of rotor housings comprises the same elements described above for the single rotor housing. According to an embodiment, each rotor of the plurality of rotors comprises the same elements described above for the single rotor housing. According to an embodiment, the above description for a single compression stage is reproduced for a plurality of compression stages. According to an aspect of the invention, a method is also provided for compressing a fluid in a rotary compressor.

According to an embodiment, the method comprises preparing a generator and a rotary machine of the Wankel type.

According to an embodiment, the method comprises a step of preparing a rotary machine of the Wankel type including a stator, which comprises a rotor housing having an inside surface delimiting an internal space. According to an embodiment, the method comprises a step of preparing a rotary machine of the Wankel type including a rotor, connected to the power generator by means of a drive shaft rotating about an axis of rotation.

According to an embodiment, the method comprises a step for conveying a fluid to be compressed to the rotor housing by means of an intake duct and through an intake port.

According to an embodiment, the method comprises a step of picking up compressed fluid from the rotor housing by means of a discharge duct and through a discharge port.

According to an embodiment, the method comprises a dynamic sealing step. According to an embodiment, the method comprises an apical dynamic sealing step. The dynamic apical seal occurs between the inside surface of the rotor housing and the lateral face of the rotor, surrounding the axis of rotation, and is designed to separate from each other two adjacent compression chambers. According to an embodiment, the dynamic apical seal occurs between the inside surface of the rotor housing and an apex (or edge of the geometrical solid defined by the rotor) of the rotor, parallel with the axis of rotation. According to an embodiment, the apical dynamic sealing is executed by a first group of apical lips. According to an embodiment, the apical dynamic sealing step is executed by the first group of the apical lips, which are made of polymeric material.

According to an embodiment, the method comprises a shaft seal. According to an embodiment, the shaft seal is executed between the drive shaft and the rotor housing.

According to an embodiment, the shaft seal is executed between the drive shaft and the support of a bearing. According to an embodiment, the shaft seal is achieved by a plurality of shaft seals.

According to an embodiment, the method comprises a dynamic lateral sealing step. According to an embodiment, in the lateral dynamic sealing step a second group of the lateral lips slide keeping contact with the inside surface of the rotor housing.

According to an embodiment, during the lateral dynamic sealing step the second group of lateral lips, positioned on a first and a second dynamic end face, both perpendicular to the axis of rotation, slide keeping contact with the inside surface of the rotor housing.

According to an embodiment, the lateral dynamic sealing step is executed by means of the second group of lateral lips made of polymeric material. According to an embodiment, the lateral dynamic sealing step is executed by means of the second group of lateral lips made of PEEK® filled with other materials.

According to an embodiment, the lateral dynamic sealing step is executed by means of the second group of lateral lips made of PEEK®. According to an embodiment, the apical dynamic sealing step is executed by means of the second group of apical lips made of PEEK®.

According to an embodiment, the shaft seal step is executed by means of the plurality of shaft seals made of polymeric material.

According to an embodiment, the shaft seal step is executed by means of the plurality of lip seals made of NBR (synthetic rubber based on acrylonitrile and butadiene).

According to an embodiment, the shaft seal step is executed by means of the plurality of lip seals made of PEEK®.

According to an embodiment, the method comprises a lateral compression step. According to an embodiment, during the lateral compression step, a plurality of lateral springs, each interposed between a respective lateral lip and the rotor, presses the respective lateral lip against the inside surface of the rotor housing.

According to an embodiment, the method comprises a recovery step. According to an embodiment, during the recovery step the compressor recirculates, by means of a collection system, leak fluid from a position downstream of the plurality of the lateral lips to limit the fluid leaks into the environment.

According to an embodiment, the recovery step comprises a step of collecting leak fluid in a collection chamber.

According to an embodiment, the method comprises a step of introducing leak fluid in a relief duct. According to an embodiment, a collection duct collects the leak fluid from the collection chamber and conveys it in the relief duct. The relief duct conveys the leak fluid outside the compressor. According to an embodiment, the collection duct conveys the leak fluid into the intake duct.

According to an embodiment, the collection duct conveys the leak fluid to the outside of the compressor to be subsequently reintroduced into the intake duct.

According to an embodiment, the method comprises an apical compression step, wherein a plurality of apical springs, each interposed between a respective apical lip and the rotor press the respective apical lip against the inside surface of the rotor housing.

Brief description of the drawings

This and other features will become more apparent from the following description of a preferred embodiment of the invention, illustrated by way of non-limiting example in the accompanying tables of drawings, in which:

- Figure 1 is a perspective view of a compressor according to the invention;

- Figure 2 is a perspective view of a part of the compressor of Figure 1 ;

- Figures 3A and 3B show the part of the compressor of Figure 2, according to a first and a second section rotated between each other about the axis of rotation of the drive shaft, respectively;

- Figure 4 is a cross section view of the compressor of Figure 1 in which the intake ports are illustrated;

- Figure 5 is a cross section view of the compressor of Figure 1 , at right angles to the sections of Figures 3A and 3B;

- Figure 6 shows an exploded view of certain structural components of the compressor of Figure 1 ;

- Figure 7 illustrates a perspective view of a detail of a drive shaft and of a rotor of the compressor of Figure 1 ;

- Figure 8 illustrates a detail of a collection system of the compressor of Figure 1 ;

- Figures 9A and 9B show a detail of an apical dynamic seal and a detail of a lateral dynamic seal of the compressor of Figure 1 , respectively;

- Figure 10 is a lateral view of the rotor of the compressor of Figure 1 ;

- Figures 10A and 10B illustrate the rotor of Figure 10, according to the sections A-A and B-B indicated in Figure 10, respectively;

- Figures 1 1 A and 1 1 B schematically illustrate the compressor of Figure 1 , in a variant which includes a plurality of rotors, positioned in series and in parallel, respectively.

Detailed description of preferred embodiments of the invention

According to one aspect of the invention, Figure 1 illustrates a rotary compressor 1. The rotary compressor 1 comprises a rotary machine 10. The compressor 1 comprises a power generator 1 A.

According to an embodiment, the power generator 1 A is an electric motor. According to an embodiment, the power generator 1 A is an internal combustion engine.

According to an embodiment, the power generator 1 A comprises a transmission shaft 1A’, from which the rotary machine 10 picks up the power.

According to an embodiment, the rotary machine 10 comprises a stator 100. According to an embodiment, the stator 100 comprises some parts which are purely structural, which perform the function of a frame.

The term stator denotes the set of parts of the rotary volumetric machine which remain stationary in opposition to the parts of the rotary machine which rotate carried by the transmission shaft 1 A’ of the power generator. According to an embodiment, the stator 100 comprises a hood 10A.

According to an embodiment, the stator 100 comprises a rotor housing 1 1. According to an embodiment, the hood 10A and the rotor housing 1 1 are connected.

According to an embodiment, the rotor housing 1 1 has an inside surface 12A. According to an embodiment, the rotor housing 11 has an internal space 12B. According to an embodiment, the inside surface 12A delimits an internal space 12B.

According to an embodiment, the rotor housing 1 1 has an epitrochoidal cross section. According to an embodiment, the rotor housing 1 1 comprises a static lateral wall 1 1 A. The static lateral wall 1 1 A has a static lateral face 1 1 A’.

According to an embodiment, the rotor housing 1 1 comprises a first static end wall 1 1 B and a second static end wall 11 C. Each of the first 11 B and second 11 C static end walls has a respective first 11 B’ and second 11 C’ static end face.

According to an embodiment, the static lateral face 11 A’, the first static end face 11 B’ and the second static end face 1 1 C’ define in their entirety the inside surface 12A of the rotor housing 1 1 and, therefore, delimit the internal space 12B of the rotor housing 1 1.

According to an embodiment, the rotor housing 1 1 comprises a passage opening. The passage opening is positioned on the first static end wall 1 1 B or on the second static end wall 1 1 C. According to an embodiment, the rotor housing 1 1 comprises two passage openings 1 1 D. According to a preferred embodiment, one passage opening 1 1 D is positioned on the first static end wall 1 1 B and the other passage opening 11 D is positioned on the second static end wall 1 1 C.

According to an embodiment, the first static end wall 1 1 B’ and the second static end wall 1 1 C’ are made of metal. According to an embodiment, the first static end wall 1 1 B’ and the second static end wall 1 1 C’ are provided with a layer of polymeric material, fixed to each static end face 1 1 B’, 1 1 C’ in such a way as to cover at least a part of the respective static end face. According to an embodiment, the first static end wall 1 1 B’ and the second static end wall 1 1 C’ have been hardened by surface heat treatment.

According to an embodiment, the static lateral face 1 1 A’ is made of metal. According to an embodiment, the static lateral face 11 A’ is provided with a layer of polymeric material, fixed to the static lateral face 11 A’ in such a way as to cover at least a part of the static lateral face 1 1 A’.

According to an embodiment, the rotary machine 10 comprises an intake duct 13A. According to an embodiment, the rotary machine 10 comprises an intake duct 13A which branches into two intake branches.

The term intake duct 13A means any element which is able to contain a fluid to be compressed and which is in communication with the intake port 13A’ in such a way as to allow the fluid to be compressed contained inside the intake duct 13A to be able to be introduced in the internal space 12B of the rotor housing 1 1.

According to an embodiment, the rotary machine 10 comprises an intake chamber 13A”. The intake chamber 13A” is configured to receive a flow of fluid to be compressed from the intake duct 13A. According to an embodiment, the intake duct comprises the intake chamber 13A”. According to this embodiment, the intake chamber 13A” can be considered as an extension of the intake duct 13A with a much more extended section and therefore with a more stationary than dynamic function.

According to an embodiment, the intake chamber 13A” is connected to the first static end face 11 B by mechanical connectors such as, for example, but not necessarily, bolts or screws. According to an embodiment, the intake chamber 13A” is connected to the intake duct 13A from which comes the fluid to be compressed.

According to an embodiment, the rotary machine 10 comprises an intake port 13A’. According to an embodiment, the rotary machine comprises two intake ports 13A’. According to an embodiment, the intake port 13A’ is positioned on the first static end wall 1 1 B.

According to another embodiment, the intake ports might also be positioned on the second static end wall 1 1 C or on the static lateral wall 1 1 A. According to an embodiment, the intake chamber 13A” can be opened on the internal space 12B of the rotor housing 11 by at least one intake port 13A’.

The intake chamber 13A” has two operational configurations. According to a first operating configuration, the intake chamber 13A” is open on the internal space 12B of the rotor housing 11 and allows the intake of the gas from the intake chamber 13A”. According to an embodiment in which the intake chamber 13A” is not present, it is the intake duct 13A which is open directly on the internal space 12B of the rotor housing 1 1 to allow the intake. According to a second operating configuration, in which the intake port 13A’ is closed, the intake chamber does not have access on the internal space 12B of the rotor housing 1 1 and the compression chamber 12B’ is isolated.

According to an embodiment, the rotary machine 10 comprises at least one discharge duct 13B. According to an embodiment, the rotary machine 10 comprises at least one discharge port 13B’.

According to an embodiment, the discharge port 13B’ is positioned on the static lateral wall 1 1 A. According to an embodiment, the discharge port 13B’ is positioned on the first static end wall 1 1 B or on the second static end wall 1 1 C.

According to an embodiment, the rotary machine comprises at least one automatic valve 131.

According to an embodiment, the rotary machine 10 comprises two discharge ducts 13B. According to an embodiment, the rotary machine 10 comprises two discharge ports 13B’. According to an embodiment, the rotary machine comprises two automatic valves 131.

According to an embodiment, each automatic valve 131 is positioned in the respective intake duct 13B. According to an embodiment, each automatic valve 131 is configured to allow the discharge of the fluid contained in the compression chamber 12B’.

According to an embodiment, each automatic valve 131 is positioned between the discharge port 13B’ and the discharge duct 13B.

According to an embodiment, the discharge port 13B’ is positioned on the static lateral wall 1 1 A.

According to an embodiment, each automatic valve 131 comprises a plug 132, connected to the static lateral wall 1 1 A.

The discharge port 13B’ and the automatic valve 131 are positioned at an end of the discharge duct 13B to allow the discharge duct 13B to collect the compressed fluid from the internal space 12B of the rotor housing 11 and convey it in a transfer duct. According to an embodiment, the rotor housing 1 1 comprises at least one through hole 14. According to an embodiment, the rotor housing 11 comprises a plurality of through holes 14.

According to an embodiment, the static lateral wall 1 1 A and the first static end wall 1 1 B are connected by mechanical connectors, such as, for example, but not necessarily, screws or bolts. According to an embodiment, the static lateral wall 1 1 A and the first static end wall 11 B are connected by welding.

According to an embodiment, the static lateral wall 1 1 A and the second static end wall 1 1 C are connected by mechanical connectors, such as, for example, but not necessarily, screws or bolts. According to an embodiment, the static lateral wall 1 1 A and the second static end wall 1 1 C are connected by welding.

According to an embodiment, the rotary machine comprises a drive shaft 15. The drive shaft 15 is configured to rotate about an axis of rotation R. According to an embodiment, the drive shaft 15 has a plurality of different profiles along its axis of rotation R.

According to an embodiment, the drive shaft 15 is connected to the transmission shaft 1 A’ of the power generator 1 A through a joint 15A.

According to an embodiment, the rotary machine 10 comprises at least one flywheel. The flywheel is keyed to the drive shaft 15. According to an embodiment, the rotary machine 10 comprises a plurality of flywheels 15B. According to an embodiment, the plurality of flywheels 15B is a plurality of counterweights configured to balance the action of the centrifugal force. According to an embodiment, the drive shaft 15 is positioned in such a way as to pass through the passage openings 1 1 D of the rotor housing 1 1. According to an embodiment, the drive shaft 15 comprises an eccentric profile 15C at a stretch of the drive shaft 15 positioned inside the internal space 12B of the rotor housing 11.

According to an embodiment, the rotary machine comprises a rotor 16.

The rotor 16 is configured to rotate in the internal space 12B of the rotor housing 1 1. According to an embodiment, the rotor 16 is connected to the drive shaft 15.

According to an embodiment, the rotor 16 rotates eccentrically relative to the axis of rotation R of the drive shaft 15.

According to an embodiment, the rotor 16 is keyed to the drive shaft 15. According to an embodiment, a ball bearing 17 is interposed between the drive shaft 15 and the rotor 16 in such a way as to allow it to rotate eccentrically. According to an embodiment, the ball bearing 17 is positioned at the eccentric profile 15C on the drive shaft 15.

The ball bearing 17 makes it possible to have a relative rotation between the drive shaft 15 and the rotor 16. In short, the ball bearing allows the drive shaft 15 to be coupled with the rotor 16 in an idle fashion.

According to an embodiment, the rotor comprises two ball bearings 17. According to an embodiment, one of the two bearings, which will be referred to as the fixed ball bearing 17’ is locked along a direction parallel to the axis of rotation R of the drive shaft 15.

The fixed ball bearing 17’ is locked by a threaded ring nut 17A. According to an embodiment, a spacer 17B is positioned between the threaded ring nut 17A and the fixed ball bearing 17’. According to another embodiment, the threaded ring nut 17A and the fixed ball bearing 17’ are in direct contact.

According to an embodiment, the rotor 16 comprises a circular crown 17A with inner toothing. According to an embodiment, the circular crown 17A is keyed to the rotor 16 and integral with it. According to an embodiment, the circular crown 17A is keyed to the rotor 16 by means of elastic connectors. These elastic connectors allow jerks due to violent variations in the drive torque transmitted to be dampened. According to an embodiment, the elastic connectors are elastic pins. According to an embodiment, the circular crown 17A is keyed to the rotor 16 with two axial connectors, configured to render the circular crown 17A and the rotor 16 integral along a direction parallel to the axis of rotation R. According to an embodiment, the stator 100 (in particular the rotor housing 11 ) comprises a gearing 17B. According to an embodiment, the gearing 17B is integral with the rotor housing 1 1. According to an embodiment, the gearing 17B is connected to the second static end wall 1 1 C of the rotor housing 11.

According to an embodiment, the circular crown 17A and the gearing 17B are coupled in such a way as to synchronise the motion of the rotor 16 inside the rotor housing 1 1.

According to an embodiment, the circular crown 17A and the gearing 17B are coupled in such a way as to allow the rotor 16 to rotate during its eccentric motion about the drive shaft 15.

This configuration allows the rotor 16 to always remain in contact with the inside surface 12A of the rotor housing 1 1.

According to an embodiment, the circular crown 17A and the gearing 17B are not lubricated, neither with grease nor with oil, but have been suitably treated with a PTFE-based covering and other fillers, in order to lower the friction coefficient.

According to an embodiment, the rotor 16 is configured to rotate inside the internal space 12B of the rotor housing 1 1 in such a way as to vary a space between the walls of the rotor 16 and walls of the rotor housing 1 1. The reciprocal position between the rotor 16 and the rotor housing 1 1 allows compression chambers 12A to be defined inside the rotor housing 1 1. The compression chambers 12A are contained in the internal space 12B of the rotor housing 1 1 so they have a compression space less than the internal space 12B.

In its rotation inside the rotor housing 1 1 , the rotor 16 is configured to open or close the intake port 13A’.

During its rotation inside the rotor housing 1 1 , the rotor 16 is configured for opening or closing the discharge port 13B’ and allowing the compressed fluid to reach the automatic valves 131.

According to an embodiment, the rotor 16 comprises a dynamic lateral face 16A, rotating about the axis of rotation R.

According to an embodiment, the dynamic lateral face 16A comprises a plurality of edges 16A’, or ridges.

According to an embodiment, the dynamic lateral face 16A comprises three edges 16A’, or ridges.

According to an embodiment, the dynamic lateral face 16A comprises more than three edges 16A’, or ridges.

According to an embodiment, the rotor 16 comprises a first dynamic end face 16B and a second dynamic end face 16C, both perpendicular to the axis of rotation R of the drive shaft 15.

In the description below, the first 16B and second 16C dynamic end faces are indicated as the two faces which, in the set of claims, are indicated as the first and second end faces of the rotor 16. It should be noted that, hereafter, the expression first dynamic end face 16B and first end face of the rotor 16 are equivalent and exchangeable. It should be noted that, hereafter, the expression second dynamic end face 16C and second end face of the rotor 16 are equivalent and exchangeable. The desired aim has been to use a different term in the description to clarify and differentiate the end faces of the rotor 16 and the end faces of the stator 100.

According to an embodiment, the rotor 16 comprises a plurality of grooves 161. According to an embodiment, the plurality of grooves 161 comprises a first group of apical grooves 161 A. According to an embodiment, the plurality of grooves 161 comprises a second group of lateral grooves 161 B.

According to an embodiment, the apical grooves 161 A of the first group of apical grooves 161 A have axial extension, along a direction parallel to the axis of rotation R, equal the axial extension of the rotor 16.

According to an embodiment, the apical grooves 161 A of the first group of apical grooves 161 A are positioned at a respective edge of the plurality of edges 16A’ of the dynamic lateral face 16A of the rotor 16.

According to an embodiment, the lateral grooves 161 B of the second group of lateral grooves 161 B are positioned close to the edge of each of the first 16B and second 16C dynamic end faces. According to an embodiment, the lateral grooves 161 B of the second group of lateral grooves 161 B extend on the entire edge of the first 16B and second 16C dynamic end faces.

According to an embodiment, the rotor 16 comprises a plurality of equalising holes 162. The plurality of equalising holes are through holes which extend from the first dynamic end face 16B to the second dynamic end face 16C. According to an embodiment, the rotor 16 comprises three equalising holes 162 for each pair of vertices 16”. According to an embodiment, in which the rotor 16 comprises six vertices 16”, the rotor comprises nine equalising holes 162.

The equalising holes 162 are very important because they allow the rotor 16 to always work in a balanced manner during the activity of the compressor 1. In effect, if a leak fluid only leaks from the second group of lateral lips 18B positioned on one of the two dynamic end faces 16B and 16C it would create a difference between the pressure applied to the first dynamic end face 16B and the pressure applied to the second dynamic end face 16C. This difference in pressure might generate movements of the rotor 16 which could adversely affect the other elements of the rotary machine 10. The plurality of equalising holes 162 guarantees the uniformity of the pressure applied to the first dynamic end face 16B and to the second dynamic end face 16C.

The presence of the equalising holes allows another important advantage. Since the centrifugal force and the inertial mass forces are dependent on the mass of the bodies in motion, the lightening of the rotor 16 by means of the equalising holes 162 reduces the effects of moving the rotor 16 and the stress deriving from the centrifugal force.

According to an embodiment, the rotary machine 10 comprises a plurality of dynamic seals 18. The plurality of dynamic seals 18 are configured for working and keeping the seal in dynamic conditions. According to an embodiment, the plurality of dynamic seals 18 includes a first group of apical lips 18A. According to an embodiment, each apical lip 18A of the first group of apical lips 18A is partly positioned inside a respective apical groove 161 A of the first group of apical grooves 161 A. According to an embodiment, the first group of apical lips 18A is configured to execute a seal between the static lateral face 1 1 A’ of the rotor housing 1 1 and the dynamic lateral face 16A of the rotor 16.

According to an embodiment, the first group of apical lips 18A is in sliding contact with the inside surface 12A of the rotor housing 1 1.

According to an embodiment, the first group of apical lips 18A is in sliding contact with the static lateral face 1 1 A’ of the rotor housing 1 1.

According to an embodiment, the first group of apical lips 18A is made of polymeric material. According to an embodiment, the polymeric material is PEEK® filled with other materials which make it possible to reduce the friction coefficient. Reference has been made to PEEK® filled with other materials without this limiting to this polymeric material but to clarify the presence of a material which seals without the need to be lubricated.

According to an embodiment, the rotary machine 10 comprises a plurality of springs 191. According to an embodiment, the plurality of springs 191 comprises a first group of apical springs 191 A. According to an embodiment, each spring of the first group of apical springs 191 A is positioned in a respective apical groove 161 A of the first group of apical grooves 161 A. According to an embodiment, each apical spring 191 A of the first group of apical springs 191 A is positioned in a respective apical groove 161 A of the first group of apical grooves 161 A, between the rotor 16 and an apical lip 18A of the first group of apical lips 18A.

According to an embodiment, each apical spring 191 A of the first group of apical springs 191 A is configured to press the respective apical lip 18A of the first group of apical lips 18A against the inside surface 12A of the rotor housing 11.

According to an embodiment, each apical spring 191 A of the first group of apical springs 191 A is configured to press a respective apical lip 18A of the first group of apical lips 18A against the static lateral face 1 1 A’ of the rotor housing 1 1.

According to an embodiment, the first group of apical springs 191 A are leaf springs. According to another embodiment, the first group of apical springs 191 A are compression springs.

According to another embodiment, the first group of apical springs 191 A are traction springs.

According to an embodiment, the plurality of dynamic seals 18 comprises a second group of lateral lips 18B. According to an embodiment, each lateral lip 18B of the second group of lateral lips 18B is partially positioned in a respective lateral groove 161 B of the second group of lateral grooves 161 B.

According to an embodiment, the second group of lateral lips 18B is configured to execute a seal between the first static end face 1 1 B’ of the rotor housing 1 1 and the first dynamic end face 16B of the rotor 16.

According to an embodiment, the second group of lateral lips 18B is configured to execute a seal between the second static end face 1 1 C’ of the rotor housing 11 and the second dynamic end face 16C of the rotor 16. According to an embodiment, the second group of lateral lips 18B is in sliding contact with the inside surface 12A of the rotor housing 1 1.

According to an embodiment, the second group of lateral lips 18B is in sliding contact with the first static end face 11 B’ and with the second static end face 1 1 C’ of the rotor housing 1 1.

According to an embodiment, the plurality of dynamic seals 18 comprises a group of vertex seals 18C.

The group of vertex seals is connected with the first group of apical lips 18A and with the group of lateral lips 18B. In other words, each vertex seal of the group of vertex seals 18C is in contact with a respective lateral lip of the second group of lateral lips 18B and with a respective apical lip of the first group of apical lips 18A. The presence of the group of vertex seals 18C makes it possible to complete the isolation of the compression chambers made in the internal space of the rotor housing. According to an embodiment, each vertex seal 18C is positioned in a respective vertex groove 161 C situated at a respective vertex 16” of the rotor.

According to an embodiment, the group of vertex seals is in contact with the first static end wall 1 1 B. According to an embodiment, the group of vertex seals is in contact with the second static end wall 1 1 C.

According to an embodiment, the group of vertex seals is in contact with the static lateral wall 1 1 A. According to an embodiment, a vertex seal of the group of vertex seals 18C may be in contact simultaneously with the first static end wall 1 1 B and with the static lateral wall 1 1 A. According to an embodiment, a vertex seal of the group of vertex seals 18C may be in contact simultaneously with the second static end wall 1 1 C and with the static lateral wall 1 1 A.

According to an embodiment, the second group of lateral lips 18B is made of polymeric material. According to an embodiment, the group of vertex seals 18C is made of polymeric material.

According to an embodiment, the polymeric material is PEEK®. Reference has been made to PEEK® without this limiting to this polymeric material but to clarify the presence of a material which seals without the need to be lubricated.

According to an embodiment, the second group of lateral lips 18B is in contact with the first 1 1 B’ or the second 1 1 C’ static end face are provided with a layer of material made of PEEK®. According to another embodiment, the second group of lateral lips 18B is made of PEEK® and the first 1 1 B’ or the second 1 1 C’ static end face are made of metal material. According to another embodiment, the second group of lateral lips 18B is made of PEEK® and the first 1 1 B’ or the second 1 1 C’ static end face are also made of PEEK®.

According to an embodiment, the plurality of springs 191 comprises a second group of lateral springs 191 B. According to an embodiment, each lateral spring 191 B of the second group of lateral springs 191 B is positioned in a respective lateral groove 161 B of the second group of lateral grooves 161 B. According to an embodiment, each lateral spring 191 B of the second group of lateral springs 191 B is positioned inside a respective lateral groove 161 B of the second group of lateral grooves 161 B, between the rotor 16 and a lateral lip 18B of the second group of lateral lips 18B.

According to an embodiment, the second group of lateral springs 191 B is configured for pressing the second group of the lateral lips 18B against the inside surface 12A of the rotor housing 1 1.

According to an embodiment, the second group of lateral springs 191 B is configured for pressing the second group of the lateral lips 18B against the first static end face 1 1 B’ of the rotor housing 1 1.

According to an embodiment, the second group of lateral springs 191 B is configured for pressing the second group of the lateral lips 18B against the second static end face 1 1 C’ of the rotor housing 1 1.

According to an embodiment, the second group of lateral springs 191 B are leaf springs. According to another embodiment, the second group of lateral springs 191 B are traction springs.

According to another embodiment, the second group of lateral springs 191 B are compression springs.

According to an embodiment, the plurality of springs 191 comprises a third group of vertex springs 191 C. According to an embodiment, each vertex spring 191 C of the third group of vertex springs 191 C is positioned in the respective vertex groove 161 C of the group of vertex seals 18C. According to an embodiment, each vertex spring 191 C of the third group of vertex springs 191 C is positioned in the respective vertex groove 161 C, between the rotor 16 and a vertex seal 18C.

According to an embodiment, the third group of vertex springs 191 C is configured for pressing the group of vertex seals 18C against the inside surface 12A of the rotor housing 1 1. According to an embodiment, the third group of vertex springs 191 C is configured for pressing the group of vertex seals 18C against the first static end face 1 1 B’ of the rotor housing 11.

According to an embodiment, the third group of vertex springs 191 C is configured for pressing the group of vertex seals 18C against the second static end face 1 1 C’ of the rotor housing 1 1.

According to an embodiment, the third group of vertex springs 191 C is configured for pressing the group of vertex seals 18C against the static lateral face 1 1 A’ of the rotor housing 1 1.

According to an embodiment, the third group of vertex springs 191 C is configured for pressing the group of vertex seals 18C against the static lateral face 11 A’ and against the second static end face 1 1 C’ of the rotor housing 11 simultaneously.

According to an embodiment, the third group of vertex springs 191 C is configured for pressing the group of vertex seals 18C against the static lateral face 1 1 A’ and against the first static end face 1 1 B’ of the rotor housing 11 simultaneously.

According to an embodiment, the third group of vertex springs 191 C are leaf springs. According to another embodiment, the third group of vertex springs 191 C are traction springs.

According to another embodiment, the third group of vertex springs 191 C are compression springs.

According to an embodiment, the first group of apical lips 18A is configured to execute the seal between different compression chambers 12A made inside the rotor housing 11 as a function of the geometry of the rotor housing 1 1 and of the rotor 16. More specifically, the first group of apical lips 18A enables a high pressure chamber not to have work leaks into adjacent low pressure chambers. It may be seen that the first group of apical lips 18A performs a sealing function of compression chambers 12A which are contained inside the rotor housing 1 1.

According to an embodiment, the second group of lateral lips 18B is configured for executing the seal between a compression chamber 12B’ made in the rotor housing 1 1 and an outside environment. Any escape through the second group of the lateral lips 18B would in fact produce a flow of fluid towards the passage openings 1 1 D. In the absence of other secondary seals, an escape through the passage openings would lead to a dispersion of fluid into the environment. Is therefore essential to provide any secondary seals to prevent the above-mentioned dispersion into the environment.

According to an embodiment, the rotary machine 10 comprises a plurality of shaft seals 19. According to an embodiment, the plurality of shaft seals 19 are positioned between the drive shaft 15 and the stator 100 of the rotary machine 10. According to an embodiment, the plurality of shaft seals 19 are positioned between the drive shaft 15 and the hood 10A of the stator 100.

According to another embodiment, at least one shaft seal 19 of the plurality of shaft seals 19 is positioned between the drive shaft 15 and the rotor housing 1 1. More specifically, according to this embodiment, at least one shaft seal 19 of the plurality of shaft seals 19 is positioned between the drive shaft 15 and an inside surface 12A, surrounding the axis of rotation R, of the passage openings of the rotor housing 1 1. According to an embodiment, the plurality of shaft seals 19 is configured to perform a seal between the internal space 12B of the rotor housing 1 1 and an outside environment. When it is stated that the plurality of shaft seals 19 is positioned between the drive shaft 15 and the stator 100, it means that the plurality of shaft seals 19 is positioned in any position of the stator 100 which encounters the flow of any leak fluid coming from the internal space 12B of the rotor housing 1 1.

According to an embodiment, the plurality of shaft seals 19 comprises a plurality of polymeric seals.

According to an embodiment, the plurality of shaft seals 19 is made with polymeric seals. According to an embodiment, the plurality of shaft seals 19 is made with lip seals made of NBR. According to an embodiment, the plurality of shaft seals 19 is made with lip seals made of PEEK®.

According to an embodiment, the plurality of shaft seals 19 is made with seals made of polymeric material. According to an embodiment, the plurality of shaft seals 19 is made with seals made of PEEK®.

According to an embodiment, the rotary machine 10 comprises a collection system 20. According to an embodiment, the collection system 20 is configured for collecting a leak fluid, from a position downstream of the second group of lateral lips 18B in a leak direction, oriented from an environment with a greater pressure to an environment with a lower pressure.

For clarity of this specification, the term“escape path F” will be defined hereafter as the flow of a leak fluid which from the rotor housing 1 1 is dispersed into the environment. The escape path F is thus characterized by a direction of escape and a sense of escape.

According to an embodiment, the collection system 20 is positioned downstream of the second group of lateral lips 18B along the escape path F.

According to an embodiment, the collection system 20 is configured for introducing the leak fluid into a relief duct, configured to transfer the leak fluid outside of the compressor 1.

The collection system 20 has the function of expelling any leak fluid coming from the rotor housing 1 1 preventing its dispersion into the environment.

According to an embodiment, the relief duct is configured to convey the fluid to the outside of the compressor 1 inside a system designed for subsequently reintroducing the fluid collected into the intake.

According to another embodiment, the collection system 20 is configured for reintroducing the leak fluid into the intake duct 13A.

The collection system 20 therefore has, in this embodiment, the function of reintroducing in intake any leak fluid coming from the rotor housing 11. According to an embodiment, the collection system 20 comprises a collection chamber 21. The collection chamber 21 is configured for collecting the leak fluid coming from the rotor housing 11.

According to an embodiment, the collection chamber 21 comprises a recovery space 21 A.

According to an embodiment, the collection chamber 21 comprises a first adjacent wall 23, surrounding the axis of rotation R.

According to an embodiment, the collection chamber 21 is inside the rotor housing 11.

According to another embodiment, the collection chamber 21 is outside the rotor housing 11.

According to an embodiment, the plurality of shaft seals 19 comprises an internal seal 22A.

The internal seal 22A is the first shaft seal which a leak fluid encounters downstream of the second group of lateral lips in the escape path.

According to an embodiment, the collection chamber 21 is delimited by the second group of lateral lips 18B and by the internal shaft seal 22A.

According to an embodiment, the leak fluid is collected after a first barrier which the leak fluid encounters in the escape path F.

According to an embodiment, the internal shaft seal 22A is interposed, along the escape path F, between the rotor housing 1 1 and the collection chamber 21. According to an embodiment, the plurality of shaft seals 19 includes an external shaft seal 22B. The external shaft seal 22B is interposed, along the escape path F, between the collection chamber 21 and the outside environment.

According to an embodiment, the collection chamber 21 is delimited by the internal shaft seal 22A and by the outer shaft 22B, along a direction parallel to the axis of rotation R. According to an embodiment, the collection chamber 21 is delimited in the direction perpendicular to the axis of rotation R by the first adjacent wall 23. The first adjacent wall 23 is a wall which surrounds the axis of rotation and is connected with the internal shaft seal 22A and the external shaft seal 22B.

According to an embodiment, the collection system 20 comprises a collection duct 24. According to an embodiment, the collection duct 24 is connected to the collection chamber 21 in a collection port 24A.

The collection duct 24 is configured for conveying the leak fluid into a relief duct. According to an embodiment, the collection duct 24 terminates at an introduction port 24B. The introduction port 24B allows access to the through holes 14 on the rotor housing which are then subsequently connected with the relief duct.

Subsequently, the relief duct may be connected to a system, outside the compressor, designed for the recirculation of the fluid collected for its introduction into the intake.

According to the embodiment in which the collection chamber 21 is delimited from the internal shaft seal 22A and by the external shaft seal 22B, the rotary machine comprises a recirculation chamber 2T. The recirculation chamber 2T is delimited, along a direction parallel to the axis of rotation, by the second group of lateral lips 18B and by the internal shaft seal 22A.

The recirculation chamber 2T is delimited, along a radial direction, perpendicular and passing through the axis of rotation, by a second adjacent wall 23’.

The second adjacent wall 23’ comprises a recirculation hole 24A’, extending along the radial direction. According to an embodiment, the recirculation hole 24A’ is configured for opening the recirculation chamber 2T on the intake chamber 13A”. According to an embodiment, the recirculation hole 24A’ is configured for opening the recirculation chamber 21’ on the intake duct 13A.

In other words, according to an embodiment, along the escape path F, a leak fluid encounters the recirculation chamber 2T and, through the recirculation hole 24A’ re-enters the intake chamber to be introduced again in the internal space 12B of the rotor housing 1 1. The collection chamber 21 is, on the other hand, configured, in this embodiment, to collect a further leak fluid, escaping from the internal shaft seal 22A.

According to an embodiment, the intake port 24B is made on the first static end wall 1 1 B of the rotor housing 1 1 or on the second static end wall 1 1 C of the rotor housing 1 1.

According to an embodiment, the intake port 24B is made on the intake duct 13A.

According to an embodiment, the collection system 20 is a multi-stage collection system. The term multi-stage collection system means a collection system 20 comprising a plurality of recovery chambers positioned in series. The term plurality of recovery chambers positioned in series means an arrangement in which the leak fluid escaping from a first collection chamber of the plurality of recovery chambers is collected from a second collection chamber of the plurality of recovery chambers, positioned downstream of the first collection chamber along the escape path F.

According to an embodiment, the rotary machine 10 comprises an air cooling system 25. According to an embodiment, the rotary machine 10 comprises a dispersion surface, configured for dissipating the heat developed by the rotary machine 10 and favouring the heat exchange with a flow of cooling air.

According to an embodiment, the refrigerating system comprises a fan 1 B, configured to perform a forced ventilation towards the compressor 1.

According to an embodiment, the refrigerating system comprises a fan 1 B, configured to perform a forced ventilation in a direction parallel to the axis of rotation R and in a direction oriented from the outside environment to the compressor 1.

According to an embodiment, the fan 1 B is configured to perform a forced ventilation in a direction parallel to the axis of rotation R and in a direction oriented from the compressor 1 to the outside environment.

According to an embodiment, the compressor 1 comprises a heat exchanger 251. According to an embodiment, the cooling system 25 comprises the heat exchanger 251. According to an embodiment, the heat exchanger 251 is configured to remove heat from the fluid coming from the internal space 12B of the rotor housing.

More specifically, the discharge duct 13B is connected to the heat exchanger 251. According to an embodiment, before a heat exchange area, the flow of the compressed fluid is divided into a plurality of exchange channels 251’. The fan 1 B is configured for conveying a flow of air towards the heat exchange area where the plurality of exchange channels 25T is positioned.

The heat exchanger makes it possible to reduce the temperature of the compressed gas making it suitable for the subsequent users. This feature of the compressor is very advantageous because it allows the compressor to set the thermal limit on the limit of thermal resistance of the seals higher than the thermal limit set by the users downstream of the compressor. According to an embodiment, the fan and the plurality of exchange channels 25T are contained inside a casing 252. The casing 252 is configured to contain the flow of air and increase the heat exchange between the fluid contained inside the exchange channels 25T and the flow of cooling air.

According to an embodiment, the rotary machine comprises a plurality of compression stages. According to an embodiment, the rotary machine comprises an additional rotor housing 1 T to form a plurality of rotor housings. According to an embodiment, the rotary machine comprises an additional rotor 16’ to form a plurality of rotors. According to an embodiment, the rotary machine comprises an additional eccentric profile 15C’, on the drive shaft 15, to form a plurality of eccentric profiles.

According to an embodiment, the eccentric profiles 15C’ of the plurality are offset in an angular fashion. In other words, the eccentric profiles 15C’ have angular positions of keying on the drive shaft which are offset to each other. This positioning allows the dynamics of the rotary machine 10 to be balanced.

According to an embodiment, the additional eccentric profile 15C’ is offset by an offset angle with respect to the eccentric profile 15C.

The presence of a plurality of rotor housings 1 1 and rotors 16, given the considerable increase of the masses, could require an additional inertia disc (flywheel).

According to an embodiment, each rotor housing 1 1 of the plurality of rotor housings comprises the same elements described above for the single rotor housing. According to an embodiment, each rotor 16 of the plurality of rotors comprises the same elements described above for the single rotor housing. According to an embodiment, the above description for a single compression stage is reproduced for a plurality of compression stages.

According to an embodiment, the plurality of compression stages can be positioned in series. According to this embodiment, which is usually used to obtain high compression ratios of the compressor, the discharge duct of a previous stage is configured for introducing the compressed fluid in the intake duct of a subsequent stage. The final compression ratio will be given by the ratio between the pressure entering the first stage of the compressor and the outlet pressure in the last stage of the compressor. According to an embodiment, the plurality of compression stages can be positioned in parallel. According to this embodiment, which is usually used for processing high fluid flow rates, each stage of the plurality of stages receives the same flow rate of fluid at the same intake pressure. The discharge pressure of each stage will be the same but, for the same number of stages, the flow rate processed will be greater with respect to a configuration in series.

According to an embodiment, the compressor comprises an intake manifold. The intake manifold is connected with each intake duct of each stage.

According to an embodiment, the compressor comprises a discharge manifold, connected with each discharge duct of each stage.

According to an aspect of the invention, the invention provides a method for compressing a fluid inside a rotary compressor 1.

According to an embodiment, the method comprises a step of preparing a power generator 1 A. According to an embodiment, the power generator 1 A receives an electrical power supply and transforms it into mechanical energy of rotation of a transmission shaft 1 A’. According to an embodiment, the power generator 1A receives a chemical power supply, for example, fuel, and transforms it into mechanical energy of rotation of a transmission shaft 1 A’.

According to an embodiment, the method comprises a step of preparing a rotary machine 10 of the Wankel type.

According to an embodiment, the rotary machine 10 comprises a stator 100, including a rotor housing 1 1 having an inside surface 12A delimiting an internal space 12B. According to an embodiment, the rotary machine 10 comprises a rotor 16, connected to the power generator 1 A by a drive shaft 15 rotating about an axis of rotation R.

According to an embodiment, the method comprises a step for conveying a fluid to be compressed. According to an embodiment, during the conveying step, the fluid to be compress is conveyed to the rotor housing 1 1. The fluid to be compressed is conveyed through an intake duct 13A. According to an embodiment, the fluid to be compressed is conveyed by means of the intake duct 13A to the rotor housing 1 1 of the stator 100, which is open on the intake duct 13A in an intake port 13A’.

According to an embodiment, the method comprises a step for picking up the compressed fluid. According to an embodiment, during the collection step, the compressed fluid is picked up from the rotor housing 11. The compressed fluid is picked up through a discharge duct 13B. According to an embodiment, the compressed fluid is picked up by the discharge duct 13B from the rotor housing 1 1 of the stator 100, which is open on the discharge duct 13B in a discharge port 13B’. According to an embodiment, the method comprises an intake step.

According to an embodiment, during the intake step, the fluid to be compressed arrives at an intake chamber 13A” through the intake duct 13A and from the intake chamber enters in the internal space 12B of the rotor housing 1 1.

During the intake step, in a synchronised fashion with the rotation by the drive shaft 15, the intake port 13A’ is opened, allowing access in the rotor housing 1 1 to the fluid to be compressed contained in the intake chamber 13A”.

According to an embodiment, the method comprises a discharge step. During the intake step, in a synchronised fashion with the rotation of the drive shaft 15, the discharge port 13B’ is opened, allowing the escape of the compressed fluid from the rotor housing 1 1 to the discharge duct 13B. In the discharge step, the automatic valves 131 control the discharge of the compressed gas.

When it is stated that the intake step occurs in a synchronised fashion with the rotation of the drive shaft 15 it means that, according to an embodiment, the drive shaft 15, during its rotation, controls the opening or closing of the intake ports.

According to an embodiment, for example, the drive shaft 15 drives the rotor 16, which by rotating is able to isolate, or put into communication, the discharge duct 13B (or intake duct) with compression chambers 12A of the rotor housing 1 1 in which is contained (or will be subsequently contained) the compressed fluid (or the fluid to be compressed).

According to other embodiments, the drive shaft 15 could transmit the motion to a camshaft which directly controls the opening or closing of the intake port 13A’ or discharge port 13B’. According to other embodiments, the intake port 13A’ or discharge port 13B’ may be a servo-valve controlled with electrical power signals.

According to an embodiment, the method comprises a step for compression of the fluid to be compressed. This compression step is due to the fact that the geometries of the rotor housing 1 1 and of the rotor 16 are shaped in such a way as to vary the volume between the rotor housing 11 and the rotor 16, when the latter is rotated.

According to an embodiment, the method comprises an apical dynamic sealing step F1. According to an embodiment, the apical dynamic sealing step F1 is a seal between the inside surface 12A of the rotor housing 1 1 and a lateral face of the rotor 16, parallel to the axis of rotation R. According to an embodiment, the apical dynamic sealing step F1 is executed by a first group of apical lips 18A. According to an embodiment, the apical dynamic sealing step F1 is executed by a first group of apical lips 18A, made of polymeric material. According to an embodiment, the apical dynamic sealing step F1 is executed by a first group of apical lips 18A, made of PEEK®.

According to an embodiment, the first group of apical lips 18A executing the apical dynamic sealing allows the hydraulic isolation between the compression chambers 12A of the rotor housing 1 1 , avoiding the passage of a fluid from a compression chamber with a greater pressure towards a compression chamber with a lower pressure. The first group of apical lips 18A executes the seal sliding in contact with the inside surface 12A of the rotor housing 1 1. According to an embodiment, the first group of apical lips 18A executes the seal along the entire axial length of the rotor 16, the length of the rotor 16 along a direction parallel to the axis of rotation R. According to an embodiment, the method comprises a dynamic lateral sealing step F2. According to an embodiment, the lateral dynamic sealing step F2 comprises a seal between the inside surface 12A of the rotor housing 1 1 and a first dynamic end face 16B of the rotor 16, perpendicular to the axis of rotation R. According to an embodiment, the lateral dynamic sealing step F2 comprises a seal between the inside surface 12A of the rotor housing 1 1 and a second dynamic end face 16C of the rotor 16, perpendicular to the axis of rotation R.

According to an embodiment, the lateral dynamic sealing step F2 is executed by a second group of lateral lips 18B.

According to an embodiment, the lateral dynamic sealing step F2 is executed by a second group of lateral lips 18B, made of polymeric material. According to an embodiment, the lateral dynamic sealing step F2 is executed by a second group of lateral lips 18B, made of PEEK®.

According to an embodiment, the second group of lateral lips 18B executing the lateral dynamic sealing allows the hydraulic isolation between the compression chambers 12A of the rotor housing 1 1 and an outside environment. The second group of lateral lips 18B executes the seal sliding in contact with the inside surface 12A of the rotor housing 1 1. According to an embodiment, the second group of lateral lips 18B executes the seal sliding in contact with the respective static end face of the rotor housing 11.

According to an embodiment, the second group of lateral lips 18B executes the seal along the edge of the first 16B and second 16C dynamic end face of the rotor 16.

In other words, during the compression step, in order to guarantee an efficient compression it is important that the compression chamber 12B’ is isolated from the other compression chambers 12A and the outside environment. The compression chamber 12B’ is isolated through the first group of apical lips 18A and the second group of lateral lips 18B. According to the embodiment in which the first group of apical lips 18A and the second group of lateral lips 18B are made of polymeric material, the compressor 1 can work without lubrication, with all the resulting advantages, known to an expert in the trade.

According to an embodiment, the method comprises a shaft sealing step F3. According to an embodiment, the shaft sealing step F3 comprises a shaft seal between the drive shaft 15 and the rotor housing 1 1. According to an embodiment, the shaft sealing step F3 is made with a plurality of shaft seals 19.

The shaft sealing step F3 allows the efficiency of the compressor 1 to be increased, thereby limiting the dispersion of fluid into the environment. In effect, according to an embodiment, the plurality of shaft seals 19, obstructs a flow of a leak fluid through its“escape path F’”, which from the rotor housing 1 1 proceeds towards the outside environment.

For clarity of this specification, the term“escape path F” will be defined hereafter as the flow of a leak fluid which from the rotor housing 1 1 is dispersed into the environment. The escape path F is thus characterized by a direction of escape and a sense of escape.

According to an embodiment, the leak fluid passes through coupling zones between the rotor housing 1 1 and the drive shaft 15. According to an embodiment, the coupling zones are passage openings 11 D on the rotor housing 11. According to an embodiment, the leak fluid passes between the drive shaft 15 and the stator 100.

According to an embodiment, the shaft sealing step F3 is achieved using seals made of polymeric material. According to an embodiment, use is made of seals (preferably polymeric) energised by springs; also, according to a possible embodiment, use is made of seals (preferably polymeric) having complex geometry.

According to an embodiment, the shaft seal step F3 is achieved by means of the lip seals made of NBR.

According to an embodiment, the shaft seal step F3 is achieved by means of the lip seals made of PEEK®.

According to an embodiment, the method comprises a lateral compression step. During the lateral compression step, a plurality of lateral springs 191 , each interposed between a respective lateral lip 18B and the rotor 16, presses the respective lateral lip 18B against the inside surface 12A of the rotor housing 1 1.

According to an embodiment, in which the rotor housing 1 1 comprises a first 1 1 B and a second 1 1 C static end wall, both perpendicular to the axis of rotation R, the plurality of lateral springs 191 presses the respective lateral lip 18B against the first 1 1 B and the second 1 1 C static end wall 11 C.

The plurality of lateral springs 191 pressing the respective lateral lip 18B keeps the lateral lip 18B in sliding contact with the inside surface 12A of the rotor housing 11 even when the respective lateral lip 18B varies its geometry due to wear.

According to an embodiment, the method comprises an apical compression step. During the apical compression step, a plurality of apical springs 191 , each interposed between a respective apical lip 18B and the rotor 16, presses the respective apical lip 18A against the inside surface 12A of the rotor housing 1 1.

According to an embodiment, in which the rotor housing 1 1 comprises a static lateral wall 1 1 A, parallel to the axis of rotation R, the plurality of apical springs 191 presses the respective apical lip 18A against the static lateral wall 1 1 A of the rotor housing 1 1.

The plurality of apical springs 191 pressing the respective apical lip 18A keeps the apical lip 18A in sliding contact with the inside surface 12A of the rotor housing 1 1 even when the respective apical lip 18A varies its geometry due to wear.

According to an embodiment, the method comprises a recovery step F4. According to an embodiment, in the recovery step F4, the compressor 1 recirculates a leak fluid through a collection system 20. According to an embodiment, in the recovery step F4, the compressor 1 recirculates a leak fluid, through a collection system 20, from a position downstream of the second group of lateral lips 18B along the escape path F, to limit losses of fluid into the environment.

In other words, according to an embodiment, in the recovery step F4, the leak fluid resulting from a leak on the second group of lateral lips 18B, is collected before the latter can disperse into the environment. It is then recirculated to be again introduced in the compression chambers 12A of the rotor housing 11.

According to an embodiment, the leak fluid recovery step F4 comprises a step of collecting leak fluid F4’ in a collection chamber 21. According to an embodiment, the collection step F4’ occurs downstream of the second group of lateral lips 18B along the escape path F of the leak fluid. According to an embodiment, the collection step F4’ occurs downstream of the second group of lateral lips 18B and upstream of the plurality of shaft seals 19, along the escape path F of the leak fluid. According to this embodiment, the collection step F4’ occurs inside the rotor housing 1 1. According to an embodiment, the collection step F4’ occurs downstream of an internal shaft seal 22A of the plurality of shaft seals 19 and upstream of an external shaft seal 22B of the plurality of shaft seals 19, along the escape path F of the leak fluid. According to this embodiment, the collection step F4’ occurs outside the rotor housing 11.

According to an embodiment, the method comprises a step of expelling the leak fluid F4”.

In this step F4”, the leak fluid, from the collection chamber 21 , is conveyed to a relief duct through a collection duct 24.

In this step F4”, according to another embodiment, the leak fluid, from the collection chamber 21 , could be conveyed to the intake duct 13A through a collection duct 24.

According to an embodiment, in which the collection chamber 21 is downstream of the plurality of shaft seals 19 along the escape path F, the collection duct 24 collects the leak fluid outside the internal space 12B of the rotor housing 11.

According to an embodiment, in which the collection chamber 21 is downstream of the plurality of shaft seals 19 along the escape path F, the method comprises an automatic recovery step.

In the automatic recovery step, a leak fluid escaping from the second group of lateral lips 18B is temporarily contained in a recirculation chamber 21’ and through a recirculation hole 24A’ is automatically reintroduced into the intake chamber 13A’ or into the intake duct 13A. The automatic recirculation is allowed since the pressure of the leak fluid is greater than that at the intake.

If a further leak occurs from the recirculation chamber 21’, the further leak fluid would be collected in the collection chamber 21 and expelled through the relief duct.

According to an embodiment, the method comprises a step for cooling the compressor 1. According to an embodiment, in the cooling step, a fan 1 B, keyed with the drive shaft 15, forces a flow of cooling air towards the compressor 1 , to allow an efficient removal of heat.

According to an embodiment, the fan 1 B force the flow of cooling air from the compressor 1 towards the outside environment.

According to an embodiment, the method comprises a step of eccentric rotation of the rotor 16 relative to the axis of rotation R of the drive shaft 15.

According to an embodiment, the method comprises a step of preparing a ball bearing 17, interposed between the drive shaft 15 and the rotor 16. According to an embodiment, the method comprises a step of coupling a circular crown 17A with inner teeth, which is keyed and integral with the rotor 16, with a gearing 17B integral with the rotor housing 1 1. In this step, the rotor 16, in its eccentric rotation rotates due to the effect of the coupling between the gearing 17A and the circular crown 17B. This rotation allows the first group of apical lips 18A to always remain in contact with the inside surface 12A of the rotor housing 1 1 .

According to an embodiment, the method comprises an idle rotation of the rotor 16 about the drive shaft 15 due to the effect of the eccentric profile 15C on which the rotor 16 is connected through a ball bearing 17.

According to an embodiment, the method comprises a step of preparing an additional rotor housing 1 T to form a plurality of rotor housings. According to an embodiment, the method comprises a step of preparing an additional rotor 16’ to form a plurality of rotors. According to an embodiment, the method comprises a step of preparing an additional eccentric profile 15C’, on the drive shaft 15, to form a plurality of eccentric profiles.