CN114303033B - Common unit for refrigerant gas treatment systems - Google Patents

Abstract

A common unit (10) for a refrigerant gas treatment system (1) is described, the common unit (10) comprising an accumulator (4), a check valve (11) and a reversing valve (3). The accumulator (4), the non-return valve (11), and the reversing valve (3) are integrated in a common unit (10). Such a system should facilitate the installation of a VRF or VRV system and should be easy to produce. For this purpose, the common unit (10) is accommodated in a housing, wherein the housing can withstand at least twice the pressure, wherein the housing comprises a housing (14) accommodating the check valve (11) and the reversing valve (3), an accumulator housing, and a tube (13) connecting the housing (14) and the accumulator housing.

Description

Common unit for refrigerant gas treatment systems

Technical Field

The present invention relates to a refrigerant gas treatment system including an accumulator, a check valve, and a reversing valve.

Background

Refrigerant gas processing systems are used, for example, in Variable Refrigerant Flow Systems (VRFs) or variable refrigerant flow Systems (VRVs), which are a subset of air conditioning systems.

In most cases, the above components are provided by different suppliers and assembled at the installation site, which requires some skill of the installer. Even if these components are assembled in a factory, this requires additional work from the manufacturer and increases costs.

Disclosure of Invention

It is an object of the present invention to facilitate the installation of a VRF or VRV system and to facilitate the production of the system.

This object is solved by a common unit for a refrigerant gas treatment system.

According to the invention, the accumulator, the non-return valve and the reversing valve are integrated in a common unit.

Such a common unit is produced and supplied by a single supplier, so that the number of suppliers can be reduced.

The common unit is accommodated in a common housing such that all parts are held together. The housing may be subjected to several times the atmospheric pressure, more in detail at least twice the atmospheric pressure. The housing includes a portion (i.e., a shell) that accommodates: check and reversing valves, accumulator housing, and tubing connecting the housing and accumulator housing. The housing may be designed to withstand a pressure higher than the accumulator housing. By integrating the components or elements into one unit, separate pressure bearing housings for the various components can be avoided. The responsibility of such a public unit is a provider. The joint and assembly time can be saved. The assembly process is improved. Furthermore, the risk of leakage is reduced. The less leakage, the more energy efficient the common cell.

Preferably, in operation, the entire common unit is pressurized by refrigerant. The housing constitutes a common outer pressure housing of the entire common unit. This gives rise to several advantages. The integrated common unit may be very small compared to a typical system in which each element has its own pressure housing. The common unit according to the invention is therefore much smaller in volume. Furthermore, material is saved since only one common pressure housing is needed. The public units are low in production cost and resource-saving. In addition, it is relatively light. The common unit according to the invention facilitates transportation, installation, maintenance, disassembly and scrapping. Furthermore, since there is only one common pressure housing, the risk of leakage is reduced.

More preferably, during operation, the entire interior of the common unit (the entire interior of the common outer pressure housing) is pressurized by the refrigerant. Of course, although there is only one common pressure housing, during operation the interior of the common outer pressure housing may be divided into different areas with different pressures. In particular, the hot zone (first zone) may be adapted to be pressurized by the discharge pressure of the compressor, wherein the cold zone (second zone) may be adapted to be pressurized by the suction pressure of the compressor. Of course, the suction pressure may be significantly less than the discharge pressure.

The portion (of the housing) housing the check valve and the reversing valve may also be denoted as upper housing portion.

In an embodiment of the invention, the upper housing part and the tube may be detachably fixed to each other. This facilitates maintenance. For example, the upper housing portion may be removably secured to the tube by a threaded connection. In particular, the tube may comprise a fixing flange, wherein the external thread is provided at the outer periphery of the fixing flange. The tube may be at least partially inserted into an insertion space on the upper housing part. The insertion space may have an at least substantially cylindrical shape. Corresponding internal threads may be provided at the outer periphery of the insertion space, for example at the lower axial end of the insertion space. The lower axial end is an end in an axial direction of the insertion space, which corresponds to the axial direction of the tube.

Additionally or alternatively, the tube may be detachably secured to the accumulator housing. For example, a flange (or block) may be provided at the upper end of the accumulator housing, and a corresponding flange may be provided at the lower end of the tube facing the accumulator housing. The upper end of the accumulator housing is the end facing the tube. The lower end of the tube is the end of the tube facing away from the upper housing part and facing in the axial direction of the accumulator housing. The flange of the tube may be connected to the flange (or block) of the accumulator housing by a plurality of threaded screws. For example, threaded screws engage corresponding threaded holes in a flange (or block) of the accumulator housing. If provided, the block may have an at least substantially hollow cylindrical shape, wherein the upper end face of the block constitutes a flange-like end face. The block may be considered part of the accumulator housing.

In a more preferred embodiment, the common unit is configured such that the actuator can be removed from the accumulator housing when the tube is disengaged from the accumulator housing. While the actuator may be (at least partially) located in the accumulator housing when the tube and upper housing portion are secured to the accumulator housing, the actuator may be secured to the tube and/or upper housing portion. Thus, if the tube is disengaged from the accumulator housing, the actuator can be easily removed from the accumulator housing. This facilitates maintenance and replacement of the actuator.

In an embodiment of the invention, the reversing valve is connected to the actuator, wherein the actuator is arranged in the cold zone (second zone) and the reversing valve is arranged in the hot zone (first zone). The actuator may be in the form of a motor, for example an electric motor. The terms "cold" and "hot" are used to summarize the temperature difference between the two regions during operation. The hot zone is adapted to receive refrigerant gas at an elevated temperature from the compressor. The cold region is adapted to be connected to the suction side of the compressor. At the suction side, the refrigerant gas has a slightly lower temperature.

Preferably, the hot and cold regions are thermally decoupled.

More preferably, the term "thermal decoupling" refers to the following: if the temperature in the first zone is 60 ℃ and the temperature in the second zone is 10 ℃ during operation, the heat transfer from the first zone to the second zone is less than 1000W, more preferably less than 600W, and most preferably less than 450W.

In an embodiment of the invention, the hot zone is arranged above the cold zone in the direction of gravity. Thus, the hot zone does not adversely affect the cold zone by convection. Heat transfer from the hot region to the cold region may be avoided or kept at least relatively small. This is advantageous for the energy efficiency of the system.

In an embodiment of the invention, the hot and cold areas are connected by a tube forming a gas channel through which the drive shaft of the actuator extends. The tube is used to direct refrigerant gas from the reversing valve to the cold zone and at the same time accommodate the drive shaft. Thus, the actuator can be placed in a cold zone, which advantageously affects the lifetime of the actuator and avoids the need to cope with high temperatures. By placing the actuator in the cold zone rather than outside the housing or shell, the use of dynamic seals can be avoided.

In an embodiment of the invention, the accumulator forms the main part of the cold zone. The accumulator may be essentially a cold zone. As mentioned above, the actuator as well as some of the sensors may be part of the cold zone.

In an embodiment of the invention, the outer shell forms a hot zone and the accumulator housing forms a cold zone. This is a cost-effective implementation. This reduces the production costs.

In an embodiment of the invention, the reversing valve is a rotary valve having an axis of rotation. The rotary valve may be driven directly by the rotary actuator. The rotary valve comprises a valve element which is rotatable relative to the valve housing. Thus, the rotary valve maintains the outer dimensions independent of the switching state of the valve.

In an embodiment of the invention, the reversing valve is a 4-way valve or a 5-way valve. The 4-way valve has four ports. The 5-way valve has five ports. One port may be connected to the discharge side of the compressor. One port may be connected to the suction side of the compressor. The remaining 2 ports may be connected to an indoor heat exchanger and an outdoor heat exchanger. If a 5-way valve is used, the remaining ports may be connected to an energy storage system, such as a PCM energy storage system (phase change material energy storage system), an indoor heat exchanger. In this way, the system can be used for heating even in the case of defrosting of the outdoor heat exchanger. During heating in public buildings, the outdoor heat exchanger acts as an evaporator. When it is defrosted, neither the indoor heat exchanger nor the outdoor heat exchanger generates suction gas. The task is then handled by: the condensed refrigerant from the indoor heat exchanger and the outdoor heat exchanger is sent through a PCM storage system where the refrigerant absorbs heat.

In an embodiment of the invention, the check valve comprises a valve element which is radially movable with respect to the rotation axis. Therefore, the movement of the check valve does not require additional space. The flow of refrigerant gas may be directed radially into the reversing valve.

As described above, the check valve and the reversing valve are mounted together in the housing. In an embodiment of the invention, the housing comprises a cylindrical wall surrounding the check valve and the reversing valve. Thus, the housing can have a considerable pressure resistance, however, a simple construction.

In an embodiment of the invention, a plurality of check valves are provided, which are distributed in a circumferential direction around the rotation axis. In this way, the flow resistance of the check valve can be minimized.

In an embodiment of the present invention, an oil separator is provided. This is particularly useful in systems that require oil for lubrication, such as compressors. The oil separator is used to remove oil droplets or other oil particles from the refrigerant gas stream.

In an embodiment of the invention, the oil separator is arranged in the hot zone. It may thus be arranged in the housing around the reversing valve and the non-return valve. The oil is removed before the refrigerant gas flow enters the reversing valve.

In an embodiment of the invention, the oil separator is arranged around the reversing valve. This makes the construction compact. It is substantially impossible for the refrigerant gas to bypass the oil separator.

In an embodiment of the invention, the accumulator comprises a U-tube inside the accumulator, which is adapted to suck the refrigerant out of the interior of the accumulator. The U-tube may be fluidly connected to the outlet of the accumulator. The outlet may be adapted to be fluidly connected to an inlet of a compressor.

Additionally or alternatively, the accumulator includes an integrated heat exchange conduit extending through an interior of the accumulator. The integrated heat exchange tube may include a first fluid port of its own and a second fluid port of its own. The integrated heat exchange tube extends through the interior of the accumulator between the first fluid port of the integrated heat exchange tube and the second fluid port of the integrated heat exchange tube. The integrated heat exchange tubes are adapted to provide heat exchange between a fluid (e.g., refrigerant) flowing through the integrated heat exchange tubes and refrigerant in the interior of the accumulator and/or refrigerant flowing in the U-tubes. Fluid flowing through the integrated heat exchange tube may flow from a first fluid port to a second fluid port or vice versa.

Since the integrated heat exchange tube extends in the interior of the accumulator, no additional heat exchanger unit is required. The accumulator housing simultaneously serves as a pressure housing for the heat exchange capacity. This saves material and weight and reduces the package size. This also reduces the production costs.

Furthermore, a separate heat exchanger would be an additional pressure system device. It must be additionally verified whether the individual heat exchangers comply with rules, standards and/or laws, in particular with respect to pressure resistance. With respect to the above-described embodiments, this is not necessary. In any event, the accumulator and its accumulator housing must be demonstrated.

More preferably, the integrated heat exchange tube at least partially encloses the U-shaped tube. This ensures the ability to exchange heat extensively between the fluid flowing through the integrated heat exchange tubes and the refrigerant flowing through the U-tubes. Furthermore, this ensures the ability to exchange heat extensively between the fluid flowing through the integrated heat exchange tubes and the refrigerant in the interior of the accumulator but outside the U-tubes.

In an embodiment of the invention, the oil separator is arranged above the accumulator in the direction of gravity. The oil separated from the refrigerant gas stream is driven by the pressure differential between the hot and cold regions and may flow into the outlet of the U-tube in the accumulator or alternatively into the compressor suction line, thereby transferring it back to the compressor.

In an embodiment of the invention, a check valve is arranged between the oil separator and the reversing valve. Thus, the oil separator removes oil from the refrigerant gas stream before the gas stream enters the check valve. In summary, this gives a fairly compact construction.

In an embodiment of the invention, the housing comprises a high pressure transmitter and the low pressure transmitter is disposed at the accumulator. In more detail, the accumulator housing may include a low pressure transmitter.

Drawings

Preferred embodiments of the present invention will now be described in more detail with reference to the accompanying drawings, in which:

figure 1 shows a refrigerant gas treatment system,

figure 2 shows a common unit of a refrigerant gas treatment system,

figure 3 shows some elements of the common cell to a larger scale,

figure 4 shows a second embodiment of a refrigerant gas treatment system,

figure 5 shows a common unit of a second embodiment of the refrigerant gas treatment system,

figure 6 shows some elements of the second embodiment of the common unit on a larger scale,

fig. 7: a third embodiment of a refrigerant gas treatment system is shown in a heating mode,

fig. 8: is a cross-sectional view through another embodiment of the common unit,

fig. 9: a third embodiment of the refrigerant gas processing system of figure 7 is shown in a cooling mode,

fig. 10: is a sectional view through a modification of the embodiment of the common unit shown in fig. 8, and

fig. 11 is an enlarged portion of fig. 8 and 10.

DETAILED DESCRIPTION OF EMBODIMENT (S) OF INVENTION

Fig. 1 schematically shows a circuit diagram of a refrigerant gas treatment system 1. The system comprises a compressor 2, a reversing valve 3 and an accumulator 4. Further, an oil separator 5 may be provided. When an oil-free system is used, the oil separator 5 may be omitted.

The system further comprises a plurality of indoor heat exchangers 6, which may for example be arranged in a common building 7, and an outdoor heat exchanger 8. Furthermore, a phase change material energy storage device 9 may be provided.

Fig. 1 shows the cooling-related conditions of the system 1. The refrigerant gas compressed by the compressor 2 is led to an outdoor heat exchanger 8, in which heat is removed from the compressed refrigerant gas and the refrigerant gas is converted into a refrigerant liquid. The refrigerant is led to an indoor heat exchanger 6, where it receives heat from the room to be cooled and is then injected back into the accumulator.

When heating is required, the reversing valve 3 is actuated to connect the output of the compressor 2, thereby supplying hot refrigerant gas to the indoor heat exchanger 6. The hot refrigerant gas transfers heat to the room to be heated and is then led back to the accumulator 4 via the outdoor heat exchanger 8. At the same time, some of the hot refrigerant gas flow may be directed to the energy storage device 9 so that thermal energy is available during the period when the outdoor heat exchanger 8 is defrosting. This improves user comfort in the building 7.

When the reversing valve 3 is actuated to move into the third position, the output of the compressor 2 is connected to the indoor heat exchanger 6 and simultaneously to the outdoor heat exchanger 8 to defrost the outdoor heat exchanger 8. The energy in the phase change material is used to be absorbed by the liquid refrigerant entering the energy storage device 9, so that an inhaled gas is produced.

Fig. 2 shows a common unit 10 by means of which some of the above-described functions can be implemented.

The common unit 10 includes an accumulator 4, an oil separator 5, a direction valve 3, and a check valve 11 that opens in a direction toward the direction valve 3. As can be seen in fig. 2 and 3, a plurality of check valves 11 may be provided instead of a single check valve. The check valves 11 are distributed in the circumferential direction around the reversing valve 3.

The reversing valve 3 is a rotary valve rotatable about a rotation axis 12. As described above, the reversing valve is a 5-way valve. An embodiment with a 4-way valve is shown in fig. 7 and described below.

The accumulator 4 is connected to a tube 13 which extends into a housing 14. The check valve 11 and the reversing valve 3 are mounted together in the housing 14, wherein the housing 14 comprises a cylindrical wall 15 surrounding the check valve 11 and the reversing valve 3.

The reversing valve 3 is actuated by an actuator, for example in the form of an electric motor 16, in particular in the form of a stepper motor. The motor 16 may be connected to the reversing valve 3 via a gearbox 17 having a gear ratio of, for example, 1:100. The drive shaft 18 of the motor-gearbox unit 16, 17 is led through the pipe 13 to the reversing valve 3. The pipe 13 simultaneously forms a gas passage from the reversing valve 3 to the accumulator 4.

The housing 14 comprises a first port 19 connected to the discharge side of the compressor 2. The housing furthermore comprises two further ports 20, 21, which can be connected to the indoor heat exchanger 6 and the outdoor heat exchanger 8. Additional ports (not visible) are provided to connect the reversing valve 3 to the energy storage device 9.

The oil separator 5 is arranged around the reversing valve 3. A check valve 11 (or check valves 11) is arranged between the oil separator 5 and the reversing valve 3.

Housing 14 also includes a high voltage transmitter 22. Low pressure transmitter 23 may be located at the accumulator.

The accumulator 4 is provided with a port 24 connected to the suction side of the compressor 2. The port 24 is formed by the end of a U-shaped tube 25. The housing 14 forms a first zone, which may be referred to as a "hot zone," because it receives hot discharge gas from the compressor 2. The accumulator 4 forms a second zone, which may be referred to as a "cold zone", because it receives refrigerant gas having a slightly lower temperature from the indoor heat exchanger 6 or from the outdoor heat exchanger 8.

The first region comprising the housing 14 is arranged in the direction of gravity above the second region comprising the reservoir 4. Therefore, the heat transferred from the casing 4 to the surrounding air cannot be transferred to the accumulator 4 by direct convection. Furthermore, the heat transfer by radiation is quite small due to the distance between the housing 14 and the accumulator 4. Furthermore, this ensures that particles, oil and liquid refrigerant droplets can automatically move into the accumulator 4.

When the oil separator 5 is provided, the housing 14 includes an oil groove 26 that is connected to a U-shaped pipe 25 in the accumulator 4 via a capillary tube 27.

Line 28 shows the path of the hot refrigerant gas flow from the compressor 2 through the first zone. This flow passes through the oil separator 5 surrounding the reversing valve 3 and the check valve 11. Thereafter, the gas flows to a destination defined by the reversing valve 3. Line 29 shows the flow path of the return flow from the indoor heat exchanger 6. The gas flows into the accumulator 4 through a pipe 13. This gas stream is essentially oil-free. It enters the end of the U-tube 25 in the accumulator 4 opposite the port 24. The end is located near the first region, i.e. near the housing 14. An oil return opening 46 is located in the lower part of the U-shaped tube 25.

Thus, the accumulator 4, the check valve 11 and the reversing valve 3 are integrated in the common unit 10. The common unit 10 may be produced by a single supplier and it is not necessary to create joints or connections between components where they are needed. These joints and connections can be produced in the factory, can be checked before delivery, and have a higher degree of reliability.

The oil separator 5 may operate in different modes, for example by centrifugal force, by flow rate reaction force and gravity, by impact in sponge and fine mesh, or by splash plates. Of course, these possibilities may be combined and the list of possibilities is not exhaustive. Additional possibilities may be used.

An air gap 30 is provided between the tube 13 and the housing 14. The air gap 30 forms a further thermal barrier between the first or hot region and the second or cold region.

The motor 16 is accommodated in the motor housing 31 together with the gear 17. The motor housing 31 is surrounded by a spring 32 in a direction toward the reversing valve 3. Thus, the drive shaft 18 generates a force pressing the rotary valve member 33 of the reversing valve 3 against the seal 34 provided at the front surface of the rotary valve member 33. The spring 32 is supported by a bracket 35 fixed to the U-shaped tube 25 in the accumulator.

The valve element 33 is preferably made of a plastic material. This improves the insulation between the cold gas flow and the hot gas flow.

The tube 13 comprises a plurality of openings 36 such that the interior of the tube 13 is connected to the interior of the accumulator 4. The gas may flow out of the pipe 13 into the accumulator 4.

Fig. 4 to 6 show a second embodiment of the refrigerant gas treatment system. Like elements are denoted by like reference numerals as in fig. 1 to 3.

The second embodiment is an oil-free system, i.e. the compressor 2 supplies refrigerant gas directly to the reversing valve 3. Thus, as shown in fig. 5, the gas flow entering the housing 14 via the first port 19 flows directly into the reversing valve 3.

Other means associated with the oil separation, such as the oil sump 26 and capillary 27, may also be omitted.

Fig. 7 shows a third embodiment of a gas treatment system similar to the system shown in fig. 1. Like elements are denoted by like reference numerals.

The first difference from the embodiment shown in fig. 1 is that the reversing valve 3 is a 4-way valve with four ports. Two of the ports are connected to an accumulator 4 and an oil separator 5. The other two ports are connected to a set of indoor heat exchanger 6 and outdoor heat exchanger 8. In this embodiment, there is no energy storage means 9.

The accumulator 4 is provided with a heat exchanger arrangement 37, which is described in more detail with reference to fig. 8.

Fig. 7 shows the flow during the heating mode. The heat exchange in the accumulator 4 ensures that the refrigerant is supercooled and thus enters the outdoor heat exchanger 8 as supercooled refrigerant, after which the supercooled refrigerant expands into the outdoor heat exchanger 8. The refrigerant will flow from the outdoor heat exchanger 8 into the accumulator 4 and from there to the compressor 2. When the outdoor is very cold, the injection valve 38 close to the liquid burst valve 39 will be activated and part of the refrigerant from the indoor heat exchanger 6 will expand into the accumulator 4 and mix with the refrigerant from the outdoor heat exchanger 8. This provides additional cooling of the suction gas, whereby overheating of the compressor 2 can be avoided. The problem of overheating of the compressor 2 can occur during very cold weather (-20 ℃). Only 5% -10% of the flow from the indoor heat exchanger 6 passes through the injection valve 38. The liquid burst valve 39 is a relief valve that opens if the pressure in the line becomes too high. This may occur when the valves before the indoor heat exchanger 6 and the outdoor heat exchanger 8 are closed, whereby the liquid in the piping is trapped.

A possible way for realizing such a heat exchanger arrangement 37 is shown in fig. 8.

The tube 13 between the accumulator 4 and the housing 14 has been reinforced by a block 40 which can house the injection valve 38 and the liquid burst valve 39 and can also house the actuator 16. The U-shaped tube 25 is provided with sleeves 41, 42 on the vertical legs such that an annular channel 43, 44 is formed around each leg. Refrigerant may be injected into the channels 43, 44 and flow vertically along the vertical legs of the U-shaped tube 25.

The channels 43, 44 may be connected at the lower end by a connecting tube 45. The connection pipe 45 allows additional heat exchange between the refrigerant flowing through the inside thereof and the refrigerant in the inside of the accumulator 4 surrounding the connection pipe 25.

The fluid channels for heat exchange within the accumulator 4, which extend through the interior of the accumulator 4 and at least partially enclose the U-shaped tubes 25, may be referred to as "integrated heat exchange tubes". In this case, the integrated heat exchange tube is constituted by the vertical channels 43, 44 and the connecting tube 45.

The large area of the surface of the integrated heat exchange tubes ensures that a large amount of heat can be exchanged within the accumulator 4.

Fig. 10 shows a modification of the heat exchanger arrangement 37 shown in fig. 8. The only difference is that the fluid ports 43a, 44a of the channels 43, 44 are located in the cross section and can thus be seen in fig. 10. For example, the refrigerant may enter through the first fluid port 43a, flow downward in the channel 43, further flow from the channel 43 into the channel 44 through the connection tube 45, flow upward in the channel 44, and then flow out through the second fluid port 44 a. By switching between the heating mode and the cooling mode, the direction of flow through the integrated heat exchange tube is reversed.

Fig. 9 illustrates flow in the refrigerant gas processing system of fig. 7 during a cooling mode. Switching the 4-way valve 3 from the first state shown in fig. 7 to the second state shown in fig. 9 causes a switch from the heating mode to the cooling mode and vice versa. In the cooling mode, the refrigerant flowing out of the outdoor heat exchanger 8 flows through the integrated heat exchange tubes. Thereby, the liquid refrigerant from the outdoor heat exchanger 8 exchanges heat with the refrigerant in the accumulator 8.

The temperature of the refrigerant entering the compressor 2 should be sufficiently above the saturation temperature of the refrigerant to avoid liquid refrigerant reaching the compressor 2 or condensing within the compressor 2. Otherwise, the compressor 2 may be damaged. If the temperature of the refrigerant flowing through the U-shaped tube 25 to the compressor is low, this increases the risk of liquid refrigerant reaching the compressor 2 and/or condensing in the compressor 2. However, when the refrigerant collected in the interior of the accumulator 4 and flowing through the U-shaped tube 25 is cold, the refrigerant is heated by the refrigerant flowing through the heat exchange tubes (inside the channels 43, 44 and the connector 45) from the outdoor heat exchanger 8. Thus, the integrated heat exchange tubes help ensure that the temperature of the refrigerant entering the compressor 2 has a temperature above the saturation temperature of the refrigerant, and that no liquid refrigerant can damage the compressor 2. On the other hand, heat exchange in the accumulator 4 enhances supercooling of the refrigerant flowing to the indoor heat exchanger 6.

In the heating mode shown in fig. 7, under normal conditions, the temperature of the gaseous refrigerant from the outdoor heat exchanger 8 reaching the accumulator 4 is lower than the temperature of the liquid refrigerant from the indoor heat exchanger 6 flowing through the integrated heat exchange tubes within the accumulator 4. Therefore, also in this case, the refrigerant that has accumulated in the interior of the accumulator 4 and flowed through the U-shaped pipe 25 is heated by heat exchange in the accumulator 4. Again, the integrated heat exchange tubes help ensure that the temperature of the refrigerant entering the compressor 2 has a temperature above the saturation temperature of the refrigerant and that no liquid refrigerant can damage the compressor 2. On the other hand, heat exchange in the accumulator 4 enhances supercooling of the refrigerant flowing to the outdoor heat exchanger 8.

In the embodiment shown in fig. 8 and its modification in fig. 10, the tube 13 is detachably fixed to the accumulator 4. This is explained with reference to fig. 11. Fig. 11 shows an enlarged portion of fig. 8 and 10 including the tube 13.

The tube 13 extends in the axial direction. At the lower end in the axial direction, the tube 13 includes a terminal flange 61 for fixing the tube 13 to the accumulator 4. At its upper end in the axial direction, the accumulator 4 comprises a block 40 firmly and sealingly fixed to the housing of the accumulator 4. Thus, the block 40 may be regarded as a part of the housing of the formed accumulator 4. The block 40 has a substantially hollow cylindrical shape. The terminal flange 61 of the tube 13 abuts the upper end face of the block 40. A number of threaded screws (not shown) are inserted through the terminal flange 61 of the tube 13 from above and engage threaded holes (not shown) provided in the block 40. Thereby, the terminal flange 61 is detachably fixed to the block 40 and thus to the accumulator 4. When the tube 13 is secured to the block 40, a seal 62 may be provided to seal between the block 40 and the tube 13.

Further, the tube 13 is detachably fixed to a housing 14 which accommodates the 4-way valve 3 and the check valve 11. In more detail, an insertion space 50 of an upper portion of the receiving tube 13 is provided in the housing 14. The insertion space 50 has a substantially cylindrical shape. It is surrounded by a sleeve-like inner wall 51 which is part of the housing 14. The inner wall 51 constitutes the inner wall of the housing 14. At the lower end 52 of the insertion space 50 in the axial direction (and thus on the lower end of the inner wall 51), an internal thread is provided. A fixing flange 63 for detachably fixing the tube 13 to the housing 14 is provided at the outer peripheral surface of the tube 13. Corresponding external threads are provided at the outer circumferential surface of the fixing flange 63. Thus, the external threads of the fixing flange 63 and the internal threads at the lower end 52 of the insertion space 50 are engaged and thus form the threaded connection 60. The tube 13 is detachably secured to the housing 14 by the threaded connection 60.

At (or at least near) the upper end of the tube 13 in the axial direction, an abutment flange 64 is provided on the tube 13. If the tube 13 is fixed to the housing 14, the abutment flange 64 abuts the annular shoulder 53 formed at the wall of the insertion space 50 (i.e., the radially inner surface of the inner wall 51). A seal 65 for sealing between the wall of the insertion space 50 and the tube 13 is provided at the outer peripheral surface of the abutment flange.

As can be seen in fig. 11, the drive shaft 18 extends in the axial direction in the interior of the tube 13. The motor-gearbox units 16, 17 are connected to a drive shaft 18. Motor-gearbox units 16, 17 are located in the accumulator 4. In particular, the upper part of the motor-gearbox unit 16, 17 is positioned within the interior of the block 40, wherein the lower part of the motor-gearbox unit 16, 17 together with the motor 16 extends further into the interior of the accumulator 4. The motor-gearbox units 16, 17 are not directly fixed to the accumulator 4. In practice, the motor-gearbox units 16, 17 are fixed to the tube 13. In more detail, the motor-gearbox unit is fixed to the lower end of the tube 13 by means of a number of threaded screws 66 which engage corresponding threaded holes provided in the lower end of the tube 13. If the pipe 13 is disconnected from the accumulator 14, the motor-gearbox-units 16, 17 are also removed from the accumulator 4. This facilitates maintenance of the motor-gearbox unit 16, 17 and replacement thereof when necessary.

If the tube 13 is fixed to the housing 14 and if the tube 13 is fixed to the accumulator 4, the housing of the housing 14, the tube 13 and the accumulator 4 form a common housing of the whole common unit. In operation, the entire interior of the common housing is pressurized by the refrigerant. The interior of the accumulator 4 is then fluidly connected to the inlet of the compressor 2. In operation, the pressure in the interior of the accumulator 4 becomes the inlet pressure (suction pressure) of the compressor 2. The hot zone (first zone) enclosed within the housing 14 is fluidly connected to the discharge outlet of the compressor 2. In operation, the pressure in the hot zone becomes the discharge pressure of the compressor 2. Of course, the discharge pressure is significantly higher than the suction pressure. In operation, the interior of the tube 13 is pressurized and is in fluid connection with the interior of the accumulator 4.

Claims (16)

1. A common unit (10) for a refrigerant gas treatment system (1), the common unit (10) comprising an accumulator (4), a check valve (11), and a reversing valve (3), wherein the accumulator (4), the check valve (11), and the reversing valve (3) are integrated in the common unit (10),

wherein the common unit (10) is accommodated in a housing, wherein the housing is capable of withstanding at least twice the atmospheric pressure, wherein the housing comprises a casing (14) accommodating the check valve (11) and the reversing valve (3), an accumulator housing, and a tube (13) connecting the casing (14) and the accumulator housing, the reversing valve (3) being connected to an actuator (16), wherein the actuator (16) is at least partially arranged in the accumulator housing, and wherein a drive shaft (18) of the actuator (16) extends through the tube (13).

2. The common unit (10) according to claim 1, wherein the housing (14) forms a hot zone and the accumulator housing forms a cold zone, wherein the actuator (16) is arranged in the cold zone and the reversing valve (3) is arranged in the hot zone, and wherein the cold zone and the hot zone are thermally decoupled from each other.

3. A common unit (10) according to claim 2, characterized in that the hot zone is arranged above the cold zone in the direction of gravity.

4. A common unit (10) according to claim 2 or 3, characterized in that the hot zone and the cold zone are connected by means of the tube (13), the tube (13) forming a gas channel, wherein said drive shaft (18) of the actuator (16) extends through the gas channel.

5. A common unit (10) according to claim 2 or 3, characterized in that the actuator (16) is a motor which is connected to the reversing valve (3) via a gearbox (17).

6. A common unit (10) according to claim 2 or 3, characterized in that the actuator (16) is a rotary actuator and the reversing valve (3) is a rotary valve having an axis of rotation (12), wherein the reversing valve (3) can be driven directly by the actuator (16).

7. A common unit (10) according to claim 6, characterized in that the reversing valve (3) is a 4-way valve or a 5-way valve.

8. A common unit (10) according to claim 6, characterized in that the check valve (11) comprises a valve element which is radially movable with respect to the rotation axis (12).

9. A common unit (10) according to claim 6, characterized in that the housing (14) in which the check valve (11) and the reversing valve (3) are accommodated together comprises a cylindrical wall (15) surrounding the check valve (11) and the reversing valve (3).

10. A common unit (10) according to claim 6, characterized in that a plurality of check valves (11) are provided, which are distributed in circumferential direction around the rotation axis (12).

11. A common unit (10) according to any of claims 2, 3 and 7 to 10, characterized in that an oil separator (5) is arranged in the hot zone.

12. A common unit (10) according to claim 11, characterized in that the oil separator (5) is arranged around the reversing valve (3).

13. A common unit (10) according to claim 11, wherein the oil separator (5) is arranged above the accumulator (4).

14. A common unit (10) according to claim 11, characterized in that the non-return valve (11) is arranged between the oil separator (5) and the reversing valve (3).

15. A public unit (10) according to any one of claims 1-3, characterized in that the housing (14) comprises a high-pressure transmitter (22) and a low-pressure transmitter (23) is arranged at the accumulator (4).

16. A refrigerant gas treatment system (1), characterized in that the refrigerant gas treatment system (1) comprises a common unit (10) according to any of the preceding claims.