ARRANGEMENT"

Field of the Invention

The present invention relates to a reciprocating compressor able to operate with two separate pressure suction lines provided with suction valves arrangement and, more particularly, to a suction valves arrangement whose suction valves have different thicknesses.

According to the present invention, the suction valves arrangement comprises at least two vane-type suction valves, preferably arranged in a mutual valve plate, wherein each of said suction valves has a specific thickness, and is especially dedicated to the drive principle thereof.

Background of the Invention

As a person skilled in the art knows, the current state of the art provides different embodiments of refrigeration systems. Besides the most simplistic embodiments (usually comprised of only one compressor, by one condenser, by one expansion device and by one evaporator) are also provided several more complex embodiments, which can be related to the concept of multiple evaporators.

In general lines are provided multiple evaporators refrigeration systems comprised of evaporators that, in such away, have interdependence between each other, and multiple evaporators' refrigeration systems comprised of evaporators totally independent of each other.

According to the present invention, only multiple evaporators' refrigeration systems comprised of evaporators totally independent of each other are relevant and, more specifically, such refrigeration systems that are comprised of a single reciprocating compressor (unlike scroll type compressors or rotary piston compressors). An example of this type of refrigeration system is described in detail in document BRPI1001359.

According to this document, the current state of the art comprises a refrigeration system (applied to a refrigerator integrated by a refrigeration compartment and a freezer) consisted of a single reciprocating compressor, a single condenser, two expansion elements and two evaporators, each of which being fluidly connected to the compressor through an exclusive suction line. It is noteworthy that each suction line runs in a determined pressure, being possible to define a high pressure line and a low pressure line. In this case, the compressor comprises two suction inlets (one for each suction line), and each of these inputs has a suction vane-type valve suction.

One of the suction valves (especially the suction valve connected to the low pressure suction line) comprises a single vane-type valve, which is moved depending on the forces performed by suction and discharge flows, i.e., comprises an automatic valve.

The other suction valve (especially the suction valve connected to the high pressure suction line) comprises a vane-type semi-automatic valve (or semi- commanded), which is remotely commanded by means of a cooperative interaction with a solenoid arranged on a valve plate (plate arranged on one end of the compression cylinder whose aim is to define the suction and discharge inlets and acting as a support base for suction and discharge valves) and also by the forces performed by suction and discharge flows when said solenoid is disabled.

In the refrigeration system described in document BRPI 001359, it is noteworthy that said two or more suction valves operate in an alternative manner, i.e., while one of the valves is operating, the other valves (eventually only a second valve) is kept out of operation.

More particularly, it is noteworthy that the cooperative action of the solenoid is exclusively dedicated to the valve that operates on the high pressure suction line. This enables the suction valve of low pressure suction line to operate when the solenoid is activated (locking the position of the suction valve of the high pressure line so as to keep it closed), and the suction valve of high pressure line to operate when the solenoid is deactivated (wherein the differential pressure is responsible for maintaining the suction valve of the low pressure line locked).

In addition, it is also highlighted the fact that document BRP11 05379 provides the use of solenoid, similarly as described in the document BRPI1001359, for semi-commanding both vane-type suction valve as the vane-type exhaust valve. As in documentBRPI1001359, at least one solenoid used in the invention described in BRPI1105379 document is located on the valve plate.

In both cases (document BRPI1001359 and documentBRPH 105379), the solenoid located on the valve plate consists of a mechanical assembly comprised of one electrical conductor winding (electrical coil) and a support structure (known as "cup", depending on its main configuration) that defines a kind of support pipe for winding electrical conductors. This pipe is vertically aligned with the center orifice (suction and discharge) wherein the semi-commanded valve operates.

As a person skilled in the art should know, "locking" the semi-commanded vane-type valve occurs due to the attractive force triggered by the activation of the solenoid. This type of reaction is explained by the electromagnetic attraction between these components.

In this context, it is also well-known that the (vane-type) valve thickness being semi-commanded is a characteristic that plays an important role in the design of a suction valves arrangement for reciprocating compressor.

That is, it is known that the thicker a vane-type valve is, less attraction force, generated by the solenoid, is needed, and hence the solenoid power consumption to lock the valve will be lower. This is due to the saturation of magnetic flux passing through the valve.

Returning to document BRPI1001359, and based on the actual embodiments inspired on the contents of this document, it is found that the two suction valves (automatic and semi-commanded) are normally made on the same metal foil having uniform thickness.

Although this type of embodiment is common and trivial, it becomes difficult to ignore the fact that this thickness uniformity of the suction valves (defined in a single metallic foil) fails to optimize the operation of one of the two valves.

If the foil, wherein the two valves are set, comprises a thickness which optimizes the operation of the semi-commanded vafve (thicker), the operation of the automatic valve can be impaired; after all, it will be more resistant to compression pressures, which ultimately change its "point" of operation. If the foil, wherein the two valves are set, comprises a thickness which optimizes the operation of the automatic valve (thinner), the operation of the semi-commanded solenoid and valve assembly may be impaired, after all, it will be necessary to generate a greater attraction force, which ultimately increases the solenoid power consumption.

Thus, it is apparent that this technical aspect is subject to improvements. It is based on the above detailed scenario which the present invention arises from.

Objectives of the invention

Thus, it is the main objective of this invention to reveal a reciprocating compressor provided with a suction valves arrangement comprising at least one automatic valve and at least one semi-commanded valve, both of which are specifically intended for a specific type of action.

Accordingly, it is an objective of this invention that the suction valves arrangement is also comprised of a solenoid having low power consumption, this consumption is beneficially influenced by the constructive characteristics of the suction valves, which can be physically unrelated to each other, so that they can be obtained in different thicknesses.

Summary of the Invention

These and other objectives of the invention disclosed herein are fully achieved by the reciprocating compressor provided with suction valves arrangement.

In general, said compressor comprising, among other basic components, at least one compression cylinder and at least one valve plate arranged on one of the ends of the compression cylinder, and, naturally, at least one suction valves arrangement Comprised of at least one vane-type suction valve and at least one vane-type semi-commanded suction valve, and at least one solenoid comprised of one electrical conductor winding and at least one support structure. Both suction valves have at least one movable portion able to interact with at least one suction orifice.

The movable portion of the automatic suction valve is moved depending on the strength of the refrigerant fluid flow of the reciprocating compressor, and the movable portion of the semi-commanded suction valve is moved depending onthe attractive force generated by the solenoid and depending onthe strength of the refrigerant fluid flow of the reciprocating compressor.

Furthermore, according to the present invention, at least a semi-commanded suction valve has a thickness greater than the thickness of at least one automatic suction valve.

Brief Description of the Drawings

The present invention will be described in detail based on Figure 1 , which illustrates, in exploded view, the preferred embodiment of the suction valves arrangement for reciprocating compressor in accordance with the present invention.

Detailed Description of the Invention

In general, it is the main objective of the present invention to provide clever means for lowering the power consumption of the solenoid responsible for the performance of the semi-commanded suction valve described in document BRPI1001359.

Therefore, it is described an double suction reciprocating compressor, as well as the reciprocating compressor described in document BRPI1001359, whose suction valves arrangement differs greatly from the current state of the art.

For reference purposes, it is noteworthy that said double suction reciprocating compressor, which is able to operate with two separate pressure suction lines, comprises a compression mechanism comprised of a compression cylinder 1 , by a valve plate 2 arranged on one end of the compression cylinder 1, and other trivial components (not shown) which necessarily integrate this type of compressor, such as a driving source able to move the movable piston arranged within said compression cylinder 1. Obviously, the aspects of traditional reciprocating compressor do not fall within the scope of the present invention.

Notably, the reciprocating compressor further comprises a suction valves arrangement comprised of at least two vane-type suction valves and at least one solenoid able to exert magnetic attraction on one of said suction valves.

More particularly, and as previously defined in document BRPI1001359, one of the suction valves is an automatic vane-type suction valve 3, and has a movable portion able to interact with its respective suction orifice mainly located in the valve plate 2. As previously explained, it is defined as "automatic suction valve", those whose movement of the free end, relative to its respective orifice, is performed only by the forces performed by the suction and discharge flows of the refrigerant fluid.

Further more, and also according to what was previously illustrated in document BRPI1001359, one of the suction valves is a vane-type semi-commanded suction valve 4, which has a movable portion able to interact with its respective suction orifice notably located on the valve plate 2. Also as previously explained, it is defined as "semi-commanded suction valve", those whose movement of the free end, relative to its respective orifice, can be performed both due to the magnetic force (force attraction) generated by the activation of the solenoid, and the forces performed by suction and discharge flows of the refrigerant flow.

The solenoid 5, which also belongs to the suction valves arrangement, comprises a conventional solenoid that is comprised of electrical conductors winding and a support structure able to be fastened to the valve plate 2 and, more particularly, able to be fastened to the valve plate 2ίη a particularly aligned manner to the semi-commanded suction valve 4.

In this context, it is noteworthy that it is not the purpose of the present invention to detail possible geometries of the automatic suction valve 3, the semi- commanded suction valve 4, or even the solenoid 5.

Furthermore, it is not the purpose of the present invention to detail possible fastening means for these components of the suction valve arrangement on the reciprocating compressor; nevertheless, it can be used fastening means known to those skilled in the art.

In fact, the core of the present invention refers to the fact that the semi- commanded suction valve 4 has a thickness greater than the thickness of the automatic suction valve 3.

More particularly, it is still evident that the ratio between the thickness of the semi-commanded suction valve 4 and the thickness of the automatic suction valve 3 is between 1 ,1 : 1 to 3: 1.

The greater thickness of the semi-commanded suction vatve 4 in relation to the automatic suction valve 3 reaches at least two important results:

• reduction of the solenoid power consumption 5, after all, the larger the metallic mass of the body to be attracted, the smaller is the magnet stress generated by the solenoid and therefore its electrical power supply maybe smaller;

• Sealing Reliability, after all, in situations where the semi-commanded suction valve 4 needs to be "closed" (through the solenoid actuation 5), the greater will be its mechanical resistance for changing its functional status, which ensures the correct functioning of the automatic suction valve 3.

On the other hand, the smaller thickness of the automatic suction valve 3 in relation to the semi-commanded suction valve 4 further results in an eventual material economy (if compared to the amount of material used in two suction valves with the same thickness).

With respect to the constructivity of the suction valves arrangement disclosed herein, it appears that the best possibility for obtaining two suction valves having different thicknesses is to manufacture the valves so that they are physically independent of each other.

Thus, it is preferred that the thinner automatic suction valve 3is generated on a greater metal foil and with more stable fastening possibilities, whereas it is preferred that the thicker semi-commanded suction valve 4 is exclusively produced, with more limited fastening possibilities.

A good constructive example is best illustrated in Figure 1 , where the automatic suction valve 3 is generated in a foil having a perimeter equal to the perimeter of the valve plate 2, both of which can be reliably fastened to each other and to the compression cylinder 1 of the reciprocating compressor. It also appears that said foil where the automatic suction 3 is formed also presents a passerby, or window, which comprises an area of passage to the semi-commanded suction valve 4, which can be directly attached to the valve plate or the foil where the automatic suction 3 is formed. Having explained the core of the invention by way of an example of a preferred embodiment, it is important to emphasize that the scope of protection "reciprocating compressor provided with suction valves arrangement" covers other possible variations, which are limited solely by the content of the claims, wherein possible equivalent arrangements are included.