COMPRESSOR

Description

[0001] The invention relates to a compressor according to the preamble of claim 1, as well as a refrigeration system according to claim 11, and an air conditioning system according to claim 12.

[0002] Such compressors find manifold applications in modern life, for example in the air conditioning of motor vehicles, such as cars or buses, in the air conditioning of railway carriages, in transport refrigeration, or in stationary applications such as supermarket refrigeration or industrial heat pump applications, etc. Furthermore, such compressors, which generally operate on the principle of reciprocating pistons, are available in many designs, for example as reciprocating piston compressors, in which the piston movement typically occurs in a radial direction (relative to a crankshaft axis extension, which simultaneously defines the axial direction), with the pistons generally also arranged at least partially spaced apart from each other in the axial direction; or as radial piston compressors, in which the piston movement, i.e.,a suction movement and a compression movement opposing this movement, essentially in the radial direction, whereby the pistons are usually not spaced apart from each other in the axial direction (radial engine geometry) or also as axial piston compressors, in which the suction and compression movement essentially takes place in one axial direction.

[0003] Due to the cyclic compression of the refrigerant, pulsations and noise occur, especially when compressed refrigerant is expelled from a cylinder in which the corresponding piston moves back and forth.

[0004] To dampen pulsations, DE 197 57 829 A1 proposes a damper channel through which compressed refrigerant from a pressure chamber downstream of the cylinder chamber passes into a high-pressure volume common to all cylinders. The damper channel is typically equipped with a 90° bend, but more commonly with a 180° bend, whereby part or even the entire channel may be formed by a pipe, the so-called impedance tube. The design of DE 197 57 829 A1 is therefore relatively complex and thus costly to manufacture.

[0005] Furthermore, DE 38 40 715 A1 discloses a valve arrangement for a wobble plate air conditioning compressor, comprising a valve plate, outlet valve leaf springs on one side of the plate and inlet valve leaf springs on the other side of the valve plate, a sealing plate arranged adjacent to the outlet valve leaf springs for sealing the high-pressure areas from the low-pressure areas, and means for jointly fastening the valve plate, the valve leaf springs, and the sealing plate in a sub-arrangement, wherein a sub-arrangement is essentially interchangeable with a second sub-arrangement at the opposite axial end of the compressor.

[0006] DD 203 937 A1 discloses a sound attenuation device, preferably for refrigerant reciprocating compressors. A device consisting of a collared tube of specific dimensions corresponding to the pressure channel is connected to the valve plate and projecting into the pressure channel. The length of the tube is, for example, 1 / 3 the length of the pressure channel, and the cross-sectional ratio of the pressure channel to the tube is greater than or equal to 3.

[0007] US Patent 5,133,647 A1 discloses a pulsation damper for use in a standard automotive air conditioning compressor. The pulsation damper consists of a body and a cap. The cap has an outer diameter dimensioned to fit into an outlet opening in the air conditioning compressor housing. The body of the pulsation damper consists of elongated, groove-like channels.

[0008] Based on the prior art discussed above, the object of the present invention is therefore to provide a compressor which has pulsation damping with a simple design, as well as a corresponding refrigeration system and a corresponding air conditioning system.

[0009] This task is solved by a compressor according to claim 1 or a refrigeration system according to claim 11, as well as an air conditioning system according to claim 12.

[0010] Accordingly, a compressor, in particular a compressor for compressing a refrigerant, comprises one or more pistons and a cylinder block and / or a compressor housing. The pistons are arranged to move back and forth in corresponding recesses (cylinders or cylinder bores), which are generally located at least partially in the compressor housing and / or in the cylinder block. The compressor also has an impedance tube and an outlet for discharging the refrigerant from the compressor, in particular an outlet flange. For each of one or more cylinders, in particular for each pair, a high-pressure volume is arranged in the compressor, into which it discharges compressed refrigerant. The compressor also has a common high-pressure volume into which the individual high-pressure volumes discharge, the common high-pressure volume being connected to the outlet.The impedance tube is located in the connection between the common high-pressure volume and the outlet. In one possible embodiment, the connection between the common high-pressure volume and the outlet is formed by the impedance tube. A shut-off valve is located upstream of the outlet, and the impedance tube is located in the connection between the common high-pressure volume and the shut-off valve.

[0011] This represents a simple and cost-effective design to implement.

[0012] Refrigeration systems and / or air conditioning systems according to the invention have a suitably designed compressor.

[0013] Further features of the invention are specified in the dependent claims.

[0014] The invention is described below by way of example with reference to the accompanying drawing and one embodiment. It shows: Fig. 1A partial view of a possible embodiment of a compressor according to the invention in a sectional view.

[0015] In the one from Fig. 1The compressor 10 shown in the figure is a compressor designed for compressing a refrigerant, in particular CO₂. The compressor 10 has several pistons 12 (only one piston 12 is shown in the figure) which are arranged to slide back and forth in recesses (cylinder bores) 14 located in a cylinder block 16 (indicated by double arrow 18). In the present described embodiment, the compressor 10 is designed as a reciprocating piston compressor, i.e., a compressor 10 in which a suction and a compression movement (reciprocating movement, as indicated above by double arrow 18) takes place in a radial direction, i.e., perpendicular to a crankshaft axis thereof. Alternatively, for example, it could be designed as an axial piston compressor, in which a reciprocating movement takes place in the axial direction, i.e.,parallel to the crankshaft axis, conceivable.

[0016] Each piston 12, its recess (cylinder bore), or cylinder 14, and a cover or valve plate 20 arranged on the cylinder block 16 define a cylinder chamber or compression volume. During a suction movement of the pistons 12, in which they are moved away from the valve plate 20, refrigerant to be compressed is drawn into the cylinder chamber via inlet valves 21. This refrigerant is then compressed in a counter-rotating compression movement (directed towards the valve plate 20) and expelled through outlet valves 22 into a high-pressure volume 24 assigned to the respective cylinder 14. In the embodiment described here, two cylinders 14 share a single high-pressure volume 24.In the embodiment described here, the inlet valves and the outlet valves are each designed as a reed valve, whereas in alternative embodiments any suitable valves, such as ring valves or reed valves, can be used.

[0017] The compressor 10 further comprises a common high-pressure volume 26 into which the individual high-pressure volumes 24 assigned to the respective cylinder(s) 14 open via a channel 28, which in alternative embodiments can also be designed as a simple bore. The common high-pressure volume 26 receives the pressurized (compressed) refrigerant, which in the embodiment described here is CO₂, from all cylinders 14 or from all individual high-pressure volumes 24 assigned to the respective cylinders 14.

[0018] The compressor 10 also has an outlet 30 for releasing the refrigerant from the compressor, which has an outlet flange 32. Considering the refrigerant flow direction during normal operation of the compressor 10, a shut-off valve 34 is arranged upstream of the outlet 30 to close the outlet accordingly.

[0019] To dampen pulsations generated during the operation of the compressor 10, particularly during the discharge of compressed refrigerant from the respective cylinder 14, and also to dampen noise caused by these pulsations, the compressor 10 has an impedance tube 36. The impedance tube 36 is arranged in the connection between the common high-pressure volume 26 and the shut-off valve 34. In the embodiment described here, the connection between the common high-pressure volume 26 and the shut-off valve 34 is even formed by the impedance tube 36. In alternative embodiments, the impedance tube 36 can also extend over or form only a portion of the connection between the common high-pressure volume 26 and the shut-off valve 34.

[0020] The impedance tube 36 acts as a vibration damper by reflecting pulsations or oscillations at its respective ends. To achieve this, the impedance tube has a pre- and post-volume to prevent feedback. The pre-volume is formed by the common high-pressure volume 26. The post-volume is formed by the volume of the application in which the compressor is integrated, for example, a refrigeration system or an air conditioning system (e.g., its inlet volume). The outlet flange 32 on the compressor is provided for connection to the post-volume. In other words, the compressor is designed for connection to a volume downstream of the impedance tube 36.

[0021] The present invention also includes a refrigeration system and an air conditioning system, both comprising a compressor according to the invention. The volume downstream of the compressor is formed within the respective refrigeration system or air conditioning system. In other words, the present disclosure also includes a refrigeration system, in particular a transport refrigeration system or a stationary refrigeration system, comprising a compressor 10 and a volume connected to the outlet 30 of the compressor. Furthermore, the present disclosure includes an air conditioning system, in particular an air conditioning system for stationary applications or an air conditioning system for mobile applications, comprising a compressor 10 and a volume connected to the outlet 30 of the compressor.

[0022] The impedance tube 36 has a constant cross-section, although in alternative embodiments variations in the cross-section, in particular steps or stepped widenings and / or narrowings, are conceivable. The specific design depends in particular on the flow conditions prevailing in the compressor 10.

[0023] The compressor 10 has a compressor housing 38. The impedance tube 36 is attached to the compressor housing 38 and has a threaded connection for screwing it to the housing. In the embodiment described here, the impedance tube 36 is fully integrated into the hermetically sealed refrigeration circuit of the compressor 10, thus eliminating the need for seals. This is therefore a sealless integration of the impedance tube 36 into the compressor 10. In alternative embodiments, it is also conceivable to arrange the impedance tube with a seal within the compressor; in other words, a sealed version is also possible, which could also be retrofitted into a compressor.

[0024] In the present embodiment, the impedance tube 36 extends from the common high-pressure volume 26 to the shut-off device (shut-off valve 34) located upstream of the outlet 30. In the present embodiment, the impedance tube 36 has no bend or curve; in other words, the impedance tube 36 is arranged as a straight tube at the appropriate location.

[0025] Optionally, the length of the impedance tube 36 is tuned so that the incoming oscillation waves are selectively freed from their harmonics (impedance tube length I = λ / 4 or fractions thereof). The wavelength l (and thus the incoming wave itself) or multiples thereof (harmonics) are eliminated. With this arrangement, pulsations can be reduced to 10-20% with minimal loss. The following relationship applies: λ = c / f (λ = wavelength, f = frequency, and c = speed of sound).

[0026] Although the invention is described with reference to embodiments with fixed combinations of features, it also includes other conceivable advantageous combinations, as specified in particular, but not exhaustively, by the dependent claims. All features disclosed in the application documents are claimed as essential to the invention insofar as they are novel, individually or in combination, compared to the prior art. Reference symbol list

[0027] 10 Compressor 12 Piston 14 Cylinder bore or cylinder 16 Cylinder block 18 Double arrow 20 Valve plate 21 Inlet valve 22 Outlet valve 24 High-pressure volume 26 Common high-pressure volume 28 Port 30 Outlet 32 ​​Outlet flange 34 Shut-off valve 36 Impedance tube 38 Compressor housing

Claims

1. A compressor (10), in particular a compressor for compressing a refrigerant, having one or a plurality of pistons (12) and a cylinder block (16), and a compressor housing which encloses the compressor (10) at least partially, the piston / pistons (12) being arranged such that they can move to and fro in corresponding cylinder bores or cylinders (14) which are arranged at least partially in the cylinder block (16) and / or in the compressor housing, the compressor (10) having, furthermore, an impedance tube (36) and an outlet (30) for outputting the refrigerant from the compressor (10), in particular an outlet flange (32), wherein, for one or more, in particular for in each case two cylinders (14), the compressor (10) has an associated high pressure volume (24) and a common high pressure volume (26), into which the individual high pressure volumes (24) open, the common high pressure volume (26) being connected to the outlet (30), and wherein the impedance tube (36) is arranged in the connection between the common high pressure volume (26) and the outlet (30) or forms the connection between the common high pressure volume (26) and the outlet (30), characterized in that a shut-off valve (34) is arranged upstream of the outlet (30) and in that the impedance tube (36) is arranged in the connection between the common high pressure volume (26) and the shut-off valve (34).

2. The compressor (10) as claimed in claim 1, characterized in that the impedance tube (36) extends as far as directly to the outlet (30) or as far as to the shut-off valve (34).

3. The compressor (10) as claimed in either of the preceding claims, characterized in that the compressor (10) has a compressor housing (38), the impedance tube (36) having a thread for screwing onto the compressor housing (38).

4. The compressor (10) as claimed in one of the preceding claims, characterized in that the individual high pressure volumes (24) which are assigned to the respective cylinder are connected in each case via a channel (28) or a bore to the common high pressure volume (26).

5. The compressor (10) as claimed in one of the preceding claims, characterized in that the compressor (10) is provided for compressing CO2 as refrigerant, and / or in that the refrigerant to be compressed is CO2.

6. The compressor (10) as claimed in one of the preceding claims, characterized in that the impedance tube (36) has a constant cross section.

7. The compressor (10) as claimed in claim 5 or 6, characterized in that the individual high pressure volumes (24) are combined into the common high pressure volume (26).

8. The compressor (10) as claimed in one of the preceding claims, characterized in that the compressor (10) has a volume which is connected upstream of the impedance tube (36).

9. The compressor (10) as claimed in one of the preceding claims, characterized in that the compressor (10) is configured for connecting or joining to a volume which is connected downstream of the impedance tube (36), in particular by way of an / the outlet flange (32).

10. The compressor (10) as claimed in one of the preceding claims, characterized in that the impedance tube (36) has a length (1) which corresponds to a quarter of the wavelength (λ) of the pulsation or vibration to be reduced or to a harmonic, or which corresponds to part of the abovementioned dimensions (1 = A / 4n, in which n is a positive integral number, in other words a number from the group of natural numbers).

11. A refrigeration system, in particular a transport refrigeration system or a stationary refrigeration system, having a compressor (10) as claimed in one of the preceding claims and a volume which is connected to the outlet (30) of the compressor.

12. An air conditioning system, in particular an air conditioning system for stationary applications or an air conditioning system for mobile applications, having a compressor (10) as claimed in one of the preceding claims and a volume which is connected to the outlet (30) of the compressor.