Reciprocating compressor

Abstract

A reciprocating compressor has a compression cylinder (2); a compression piston (3) engaged slidingly inside the compression cylinder (2); a linear actuator (4) configured to actuate the sliding of the compression piston (3) inside the compression cylinder (2); a dissipation chamber (5), which is fluidically connected to the compression cylinder (2) and is configured to contain compressed gas exiting the compression cylinder (2); a cooling circuit (6) comprising a first duct (7), which is formed in the linear actuator (4) so as to allow a cooling fluid to pass through, and a second duct (8), which is formed in the compression cylinder (2) and is in fluidic communication with the first duct (7) so as to allow the cooling fluid to pass through; and a supply assembly (9) configured to supply the cooling fluid to the cooling circuit (6).

Description

[0001] Description

[0002] Title

[0003] Technical field

[0004] The present invention relates to a reciprocating compressor, in particular a piston compressor.

[0005] Prior art

[0006] Reciprocating compressors of known type generally comprise an outer casing, a compression cylinder coupled to the outer casing by means of a suspension system, a compression piston engaged slidingly inside the compression cylinder, a linear actuator of electric type configured to actuate the sliding of the compression piston inside the compression cylinder, and a lubrication circuit configured to lubricate the compression piston with oil.

[0007] During the operation of the compressor, because of the electrical current which is supplied to the linear actuator, the friction caused by the sliding of the compression piston inside the compression cylinder, and the compression of the gas inside the compression cylinder, heat is generated inside the compressor and, consequently, is it is necessary to cool the internal components of the compressor to prevent overheating of the compressor and to improve its operating efficiency.

[0008] In compressors of known type, the heat generated inside the compression cylinder is partially dissipated by virtue of the flow of oil in the lubrication circuit. However, this method of dissipating the heat is not very efficient and affects the performance of the compressor. Subject matter of the invention

[0009] It is an aim of the present invention to produce a reciprocating compressor which is capable of overcoming the drawbacks described above.

[0010] In accordance with the present invention, there is produced a reciprocating compressor comprising:

[0011] - a compression cylinder extending along a central axis;

[0012] - a compression piston engaged slidingly inside the compression cylinder;

[0013] - a linear actuator configured to actuate the sliding of the compression piston inside the compression cylinder;

[0014] - a dissipation chamber, which is fluidically connected to the compression cylinder and is configured to contain compressed gas exiting the compression cylinder;

[0015] - a cooling circuit comprising a first duct, which is formed in the linear actuator so as to allow a cooling fluid to pass through the linear actuator, and a second duct, which is formed in the compression cylinder and is in fluidic communication with the first duct so as to allow the cooling fluid to pass within the compression cylinder; and

[0016] - a supply assembly configured to supply the cooling fluid to the cooling circuit.

[0017] By virtue of the present invention, it is possible to dissipate heat from the reciprocating compressor efficiently, enhancing the performance of the reciprocating compressor.

[0018] In practice, the cooling circuit makes it possible to convey a cooling fluid in the linear actuator, close to the dissipation chamber, and in the compression cylinder, in such a way as to directly cool the compression piston, the compression cylinder, the linear actuator and the dissipation chamber.

[0019] Brief description of the figures Further features and advantages of the present invention will become clear from the following description of non-limiting example embodiments thereof, provided with reference to the Figures of the attached drawings, in which:

[0020] - Figure 1 is a view in cross section, with parts removed for the sake of clarity, of a reciprocating compressor produced in accordance with the present invention; and

[0021] - Figure 2 is a view in cross section, with parts removed for the sake of clarity, of a detail of the reciprocating compressor of Figure 1 .

[0022] Preferred embodiment of the invention

[0023] With reference to Figure 1 , a reciprocating compressor is generally designated by the reference numeral 1 , which reciprocating compressor may, in particular, be used in an electrical appliance, such as a refrigerator, an air conditioning unit or a heat pump.

[0024] The reciprocating compressor 1 comprises a compression cylinder 2 extending along a central axis A1 ; a compression piston 3 engaged slidingly inside the compression cylinder 2; a linear actuator 4 configured to actuate the sliding of the compression piston 3 inside the compression cylinder 2; a dissipation chamber 5, which is fluidical ly connected to the compression cylinder 2 and is configured to contain compressed gas exiting the compression cylinder 2; a cooling circuit 6 comprising a duct 7, which is formed in the linear actuator 4 so as to allow a cooling fluid to pass through the linear actuator 4, and a duct 8, which is formed in the compression cylinder 2 and is in fluidic communication with the duct 7 so as to allow the cooling fluid to pass within the compression cylinder 2; and a supply assembly 9 configured to supply the cooling fluid to the cooling circuit 6.

[0025] In accordance with the present invention, the linear actuator 4 is configured to control the reciprocating sliding movement of the compression piston 3 inside the compression cylinder 2 in such a way as to selectively take in gas into the compression cylinder 2 and compress said gas inside the compression cylinder 2. In practice, said reciprocating sliding movement of the compression piston 3 comprises an intake stroke, in which the gas is taken into the compression cylinder 2, and a compression stroke, in which the compression piston 3 compresses the gas taken into the compression cylinder 2.

[0026] In particular, the linear actuator 4 is of electric type and comprises a stator portion 10 and a movable portion 11 , which is provided with permanent magnets and is coupled to the stator portion 10 slidingly along the central axis A1.

[0027] In more detail, the stator portion 10 is integrally coupled to the compression cylinder 2, is of annular shape and extends around the central axis A1 . Furthermore, the stator portion 10 is provided with an annular sliding seat 12. The movable portion 11 is of annular shape and is engaged slidingly inside the sliding seat 12.

[0028] Furthermore, the reciprocating compressor 1 comprises a connection frame 13, which rigidly secures to one another the stator portion 10 of the linear actuator 4, the compression cylinder 2 and the dissipation chamber 5. In other words, the compression cylinder 2, the stator portion 10 of the linear actuator 4, the dissipation chamber 5 and the connection frame 13 are integral with one another.

[0029] In particular, the reciprocating compressor 1 comprises an outer casing 14 and an elastic assembly 15, which elastically connects the stator portion 10 of the linear actuator 4 to the outer casing 14. In more detail, the outer casing 14 comprises a base support 30.

[0030] In practice, the elastic assembly 15 forms a suspension system 16, which comprises elastic elements 17 arranged between the outer casing 14 and the stator portion 10 of the linear actuator 4 and elastically supports the linear actuator 4, in particular in a substantially vertical direction.

[0031] In the case described and illustrated here, which is not limiting on the present invention, each elastic element 17 comprises a helical spring and is configured to selectively be compressed and extend when the distance between the outer casing 14 and the stator portion 10 of the linear actuator 4 varies. In particular, each elastic element 17 extends in a substantially vertical direction. Furthermore, the reciprocating compressor 1 comprises a support element 18, which is integrally coupled to the stator portion 10 of the linear actuator 4 and is interposed between the linear actuator 4 and the elastic assembly 15.

[0032] In particular, the dissipation chamber 5 is configured to dissipate pressure waves generated by the phases of compression of the gas inside the compression cylinder 2.

[0033] In the case described and illustrated here, which is not limiting on the present invention, the stator portion 10 of the linear actuator 4 is arranged around the dissipation chamber 5. In more detail, the dissipation chamber 5 is arranged between the compression cylinder 2 and the support element 18.

[0034] In accordance with the present invention, the reciprocating compressor 1 comprises a connection element 19, which connects the compression piston 3 to the movable portion 11 of the linear actuator 4, and elastic elements 20, which extend in a direction substantially parallel to the central axis A1 and elastically connect the connection element 19 to the connection frame 13.

[0035] Furthermore, the reciprocating compressor 1 comprises a dissipation chamber

[0036] 21 , which is in fluidic communication with the compression piston 3 and the compression cylinder 2, and is configured to contain the gas entering the compression cylinder 2 in such a way as to dissipate pressure waves generated by the phases of intake and compression of the gas inside the compression cylinder 2.

[0037] In accordance with the present invention, the cooling circuit 6 comprises a duct

[0038] 22, which is formed in the linear actuator 4 and is fluidically connected to the duct 8 so as to allow a cooling fluid to pass through the linear actuator 4.

[0039] In practice, the duct 8 is arranged between the duct 7 and the duct 22 and fluidically connects the duct 7 to the duct 22.

[0040] In particular, the duct 7 and the duct 22 extend through the stator portion 10 of the linear actuator 4 in respective directions substantially parallel to the central axis A1 . In more detail, the duct 7 and the duct 22 are arranged close to the dissipation chamber 5 in such a way that the passage of the cooling fluid through the ducts 7 and 22 makes it possible to cool the dissipation chamber 5.

[0041] Furthermore, the cooling circuit 6 comprises a duct 23, which is formed in the connection frame 13 and fluidically connects the ducts 7 and 8; and a duct 24, which is formed in the connection frame 13 and fluidically connects the ducts 8 and 22.

[0042] In particular, the supply assembly 9 comprises at least one supply pump 25 fluidically connected to the duct 7.

[0043] In the case described and illustrated here, which is not limiting on the present invention, the supply assembly 9 comprises a plurality of supply pumps 25 arranged parallel to one another between the outer casing 14 and the stator portion 10 of the linear actuator 4. In particular, the supply assembly 9 comprises one or more supply pumps 25 in parallel.

[0044] In more detail, each supply pump 25 is of reciprocating type, comprises a pumping cylinder 26 and a pumping piston 27 engaged slidingly in the pumping cylinder 26, and is configured to dampen the oscillations of the stator portion 10 with respect to the outer casing 14 and supply the cooling fluid to the cooling circuit 6.

[0045] In particular, each supply pump 25 extends along a respective longitudinal axis A2 substantially parallel to the central axis A1 of the compression cylinder 2.

[0046] In practice, each supply pump 25 is coupled to the stator portion 10 of the linear actuator 4 and to the outer casing 14 in such a way as to be actuated by the oscillations of the stator portion 10 with respect to the outer casing 14.

[0047] In more detail, each supply pump 25 is coupled to the stator portion 10 of the linear actuator 4 and to the outer casing 14 in parallel with the elastic assembly 15. In this way, the elastic elements 17 and the supply pump 25 form a suspension system of the spring-damper type. In the case described and illustrated here, which is not limiting on the present invention, each supply pump 25 is integrated in a respective elastic element 17. In practice, each supply pump 25 is arranged inside the helical spring of the respective elastic element 17.

[0048] Note that the supply pumps 25 may take up any other position in the space between the outer casing 14 and the stator portion 10 of the linear actuator 4, without the need to be integrated in respective elastic elements 17.

[0049] The supply assembly 9 is immersed in the cooling liquid, which is contained inside the casing 14, in particular between the base support 30 and the support element 18, and is in fluidic communication with an inlet and with an outlet of the cooling circuit 6.

[0050] In particular, the cooling circuit 6 comprises a duct 28, which extends through the support element 18 and fluidically connects the supply pump 25 to the duct 7; and a duct 29, which extends through the support element 18 and fluidically connects the duct 22 to the outlet of the cooling circuit 6.

[0051] With reference to Figure 2, the duct 8 is of annular shape and extends circumferentially inside the compression cylinder 2.

[0052] In particular, the duct 8 is delimited by the compression cylinder 2 and by the compression piston 3. In this way, it is possible to lubricate the gap between the compression cylinder 2 and the compression piston 3 with the cooling fluid.

[0053] In use and with reference to Figure 1 , the actuation of the stator portion 10 of the linear actuator 4 causes the movable portion 11 to slide in the sliding seat 12 along the central axis A1. Since the movable portion 11 is rigidly secured to the connection elements 19 and to the compression piston 3, the sliding of the movable portion 11 in the sliding seat 12 causes the sliding of the compression piston 3 inside the compression cylinder 2. The elastic elements 20 generate a return force between the connection frame 13 and the connection elements 19 which causes the reciprocating sliding movement of the compression piston 3 inside the compression cylinder 2 in such a way as to selectively take in and compress the gas in the compression cylinder 2.

[0054] Because of the electrical current which is supplied to the linear actuator 4, the friction caused by the sliding of the compression piston 3 inside the compression cylinder 2 and the compression of the gas in the compression cylinder 2, heat is generated inside the reciprocating compressor 1.

[0055] The oscillations of the stator portion 10 of the linear actuator 4 with respect to the outer casing 14 give rise to the intake stroke and the delivery stroke of the pumping piston 27 inside the pumping cylinder 26. In this way, the supply pump 25 supplies the cooling fluid to the cooling circuit 6 in such a way as to dissipate heat from the compressor 1 and, at the same time, lubricate the gap between the compression cylinder 2 and the compression piston 3.

[0056] In particular, the cooling fluid supplied by the supply pump 25 flows in succession through the duct 28, the duct 7, the duct 23, the duct 8, the duct 24, the duct 22 and the duct 29, and exits via an outlet of the duct 29.

[0057] Lastly, it is clear that the present invention comprises other alternatives of the embodiments described that fall within the scope of protection of the attached claims

Claims

Claims1 . Reciprocating compressor comprising:- a compression cylinder (2) extending along a central axis (A1);- a compression piston (3) engaged slidingly inside the compression cylinder (2);- a linear actuator (4) configured to actuate the sliding of the compression piston (3) inside the compression cylinder (2);- a dissipation chamber (5), which is fluidically connected to the compression cylinder (2) and is configured to contain compressed gas exiting the compression cylinder (2);- a cooling circuit (6) comprising a first duct (7), which is formed in the linear actuator (4) so as to allow a cooling fluid to pass through the linear actuator (4), and a second duct (8), which is formed in the compression cylinder (2) and is in fluidic communication with the first duct (7) so as to allow the cooling fluid to pass within the compression cylinder (2); and- a supply assembly (9) configured to supply the cooling fluid to the cooling circuit (6)2. Reciprocating compressor according to Claim 1 , in which the cooling circuit (6) comprises a third duct (22), which is formed in the linear actuator (4) and is fluidically connected to the second duct (8) so as to allow a cooling fluid to pass through the linear actuator (4).

3. Reciprocating compressor according to Claim 2, in which the second duct (8) is arranged between the first duct (7) and the third duct (22) and fluidically connects the first duct (7) to the third duct (22).

4. Reciprocating compressor according to Claim 2 or 3, in which the first and the third duct (7, 22) are arranged close to the dissipation chamber (5).

5. Reciprocating compressor according to one of Claims 2 to 4, and comprising a connection frame (13), which rigidly secures to one another the linear actuator (4) and the compression cylinder (2); the cooling circuit (6) comprising a fourth duct (23), which is formed in the connection frame (13) and fluidically connects the first duct (7) and the second duct (8), and a fifth duct (24), which is formed in the connection frame (13) and fluidically connects the second duct (8) and the third duct (22).

6. Reciprocating compressor according to any of the preceding claims, in which the supply assembly (9) comprises at least one supply pump (25) fluidically connected to the first duct (7).

7. Reciprocating compressor according to any of the preceding claims, in which the second duct (8) is of annular shape and extends circumferentially inside the compression cylinder (2).

8. Reciprocating compressor according to any of the preceding claims, in which the second duct (8) is delimited by the compression cylinder (2) and by the compression piston (3).

Images