CN114303033A

CN114303033A - Common unit for refrigerant gas processing system

Info

Publication number: CN114303033A
Application number: CN202080060731.9A
Authority: CN
Inventors: 约翰·范贝克; 布鲁斯·布斯比; 迈克尔·伯克伦德
Original assignee: Danfoss AS
Current assignee: Danfoss AS
Priority date: 2019-08-27
Filing date: 2020-08-27
Publication date: 2022-04-08
Anticipated expiration: 2040-08-27
Also published as: CN114303033B; WO2021037966A1

Abstract

A common unit (10) for a refrigerant gas handling 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 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 be subjected to at least twice the pressure, wherein the housing comprises a housing (14) accommodating the non-return valve (11) and the reversing valve (3), an accumulator housing, and a pipe (13) connecting the housing (14) and the accumulator housing.

Description

Common unit for refrigerant gas processing system

Technical Field

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

Background

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

In most cases, the components are supplied by different suppliers and assembled at the installation site, which requires some skill of the installer. Even if these components are assembled in the factory, this requires additional work by 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 having the features of claim 1.

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

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

The common unit is housed in a common housing such that all parts are held together. The housing may be subjected to several times atmospheric pressure, more in detail at least two times atmospheric pressure. The housing includes a portion (i.e., a shell) that houses: a check valve and a diverter valve, an accumulator housing, and a tube connecting the housing and the accumulator housing. The housing may be designed to withstand higher pressures than the accumulator housing. By integrating the components or elements into one unit, separate pressure housings for the various components can be avoided. The responsibility of such a common unit lies with one supplier. Joints 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 the refrigerant. The shells constitute a common outer pressure shell of the entire common unit. This results in several advantages. The integrated common unit can be very small compared to a typical system where each element has its own pressure housing. The common unit according to the invention is therefore much smaller in volume. Furthermore, since only one common pressure housing is required, material is saved. The common unit is less expensive to produce and saves resources. Furthermore, 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 shell) is pressurized by the refrigerant. Of course, although there is only one common pressure shell, during operation the interior of the common outer pressure shell may be divided into different regions with different pressures. In particular, the hot zone (first zone) may be adapted to be pressurized by a discharge pressure of the compressor, wherein the cold zone (second zone) may be adapted to be pressurized by a suction pressure of the compressor. Of course, the suction pressure may be significantly less than the discharge pressure.

The portion (of the housing) containing the check valve and the reversing valve may also be denoted as the 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 with the tube by a threaded connection. In particular, the tube may comprise a fixing flange, wherein the external thread is provided at an outer circumference of the fixing flange. The tube may be at least partially inserted into the insertion space on the upper housing part. The insertion space may have an at least substantially cylindrical shape. A corresponding internal thread may be provided at the outer circumference 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 axial direction corresponds to an axial direction of the tube.

Additionally or alternatively, the tube may be removably secured to the accumulator housing. For example, a flange (or block) may be provided at an upper end of the accumulator housing and a corresponding flange may be provided at a 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 facing away from the upper housing part and facing in the axial direction of the tube 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 a block is 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. Although 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 directional valve is connected to the actuator, wherein the actuator is arranged in the cold region (second region) and the directional valve is arranged in the hot region (first region). 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 from the compressor at an elevated temperature. The cold area 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 "thermally decoupled" 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 zone to the cold zone can be avoided or kept at least rather 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 passage through which the drive shaft of the actuator extends. The tube serves to conduct the refrigerant gas from the reversing valve to the cold region and at the same time to accommodate the drive shaft. Thus, the actuator may be placed in a cold area, which advantageously affects the lifetime of the actuator and avoids the need to cope with high temperatures. By placing the actuator in a cold area rather than outside the housing or enclosure, the use of dynamic seals can be avoided.

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

In an embodiment of the invention, the housing forms a hot zone and the accumulator housing forms a cold zone. This is a cost efficient implementation. This reduces the production cost.

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 includes a valve member that is rotatable relative to a valve housing. Thus, the rotary valve maintains the outer dimension independent of the switching state of the valve.

In an embodiment of the present invention, the directional 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 the indoor heat exchanger and the 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 to perform heating even in the case where the outdoor heat exchanger performs defrosting. During heating in public buildings, the outdoor heat exchanger serves as an evaporator. When it is defrosted, neither the indoor heat exchanger nor the outdoor heat exchanger generates suction gas. This task is then handled by: condensed refrigerant from the indoor and outdoor heat exchangers 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 axis of rotation. Thus, no additional space is required for the movement of the check valve. The refrigerant gas flow may be directed radially into the reversing valve.

As described above, the check valve and the direction valve are installed together in the housing. In an embodiment of the invention, the housing comprises a cylindrical wall surrounding the check valve and the diverter valve. Therefore, the housing can have a considerable pressure resistance, however, a simple configuration.

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

In an embodiment of the invention, an oil separator is provided. This is particularly useful in systems requiring oil for lubricating, for example, compressors. Oil separators are 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. Thus, it may be arranged in the housing around the reversing valve and the non-return valve. The oil is removed before the refrigerant gas stream enters the reversing valve.

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

In an embodiment of the invention, the accumulator comprises a U-shaped tube inside the accumulator adapted to suck refrigerant out of the interior of the accumulator. The U-shaped tube may be fluidly connected to an 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 tube extending through an interior of the accumulator. The integrated heat exchange tube may include its own first fluid port and its own second fluid port. The integrated heat exchange tube extends through an 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 tube is adapted to provide heat exchange between a fluid (e.g., refrigerant) flowing through the integrated heat exchange tube and refrigerant in the interior of the accumulator and/or refrigerant flowing in the U-shaped tube. Fluid flowing through the integrated heat exchange tubes may flow from the first fluid port to the second fluid port, or vice versa.

Since the integrated heat exchange conduit 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, the separate heat exchanger would be an additional pressure system device. It must additionally be proven whether the individual heat exchangers comply with regulations, standards and/or laws, in particular with regard to pressure resistance. This is not essential with respect to the above embodiments. In any event, the accumulator and its accumulator housing must be certified.

More preferably, the integrated heat exchange tubes at least partially surround the U-shaped tubes. 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 flow is driven by the pressure differential between the hot and cold regions and may flow into the outlet of the U-tubes in the accumulator or, alternatively, into the compressor suction line, thereby passing it back to the compressor.

In an embodiment of the invention, a check valve is disposed between the oil separator and the diverter 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 rather compact construction.

In an embodiment of the invention, the housing comprises a high pressure transmitter and the low pressure transmitter is arranged 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 handling system,

figure 2 shows the common units of a refrigerant gas handling system,

figure 3 shows some elements of the common unit on a larger scale,

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

figure 5 shows the common unit of a second embodiment of the refrigerant gas handling 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 treatment system of figure 7 is shown in a cooling mode,

FIG. 10: is a modified sectional view through the embodiment of the common unit shown in fig. 8, an

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

Detailed Description

Fig. 1 schematically shows a circuit diagram of a refrigerant gas treatment system 1. The system includes a compressor 2, a reversing valve 3, and an accumulator 4. Furthermore, 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 conditions of the system 1 in relation to cooling. The refrigerant gas compressed by the compressor 2 is directed to an outdoor heat exchanger 8 where heat is removed from the compressed refrigerant gas and the refrigerant gas is converted to 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 to the accumulator.

When heating is required, the reversing valve 3 is actuated to connect the output of the compressor 2 to supply 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 periods when the outdoor heat exchanger 8 is defrosted. 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 intended to be absorbed by the liquid refrigerant entering the energy storage device 9, so that suction gas is generated.

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

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

The reversing valve 3 is a rotary valve which can be rotated about an axis of rotation 12. As mentioned above, the diverter valve is a 5-way valve. An embodiment having 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 non-return valve 11 is mounted together with the reversing valve 3 in this housing 14, wherein the housing 14 comprises a cylindrical wall 15 surrounding the non-return 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 a stepper motor. The motor 16 may be connected to the reversing valve 3 via a gearbox 17 having a transmission 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 selector 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 further comprises two

further ports

20, 21 which can be connected to the indoor heat exchanger 6 and the outdoor heat exchanger 8. A further port (not visible) is provided to connect the reversing valve 3 to the energy storage device 9.

An 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. The low pressure transmitter 23 may be provided 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 region, which may be referred to as a "hot region," because it receives hot discharge gas from the compressor 2. The accumulator 4 forms a second region, which may be referred to as a "cold region", in that it receives refrigerant gas having a slightly lower temperature from the indoor heat exchanger 6 or from the outdoor heat exchanger 8.

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

When an oil separator 5 is provided, the housing 14 includes an oil groove 26 that is connected to the 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. The flow passes through the oil separator 5 surrounding the reversing valve 3 and the check valve 11. Thereafter, the gas flows to the destination defined by the diverter valve 3. Line 29 shows the flow path of the return flow from the indoor heat exchanger 6. Gas flows into the accumulator 4 through the pipe 13. This gas stream is substantially oil-free. It enters the end of the U-shaped 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 a common unit 10. The common unit 10 may be produced by a single supplier and does not have to create joints or connections between components where they are needed. These joints and connections can be produced in the factory, can be inspected prior to delivery, and have a higher degree of reliability.

The oil separator 5 can be operated in different modes, for example by centrifugal force, by flow velocity reaction force and gravity, by impact in sponges and fine mesh, or by splash plates. Of course, these possibilities can be combined and the list of possibilities is not exhaustive. Further 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 the direction towards the reversing valve 3. Thus, the drive shaft 18 generates a force that presses 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 thermal insulation between the cold gas stream and the hot gas stream.

The tube 13 includes a plurality of openings 36 so that the interior of the tube 13 is connected to the interior of the accumulator 4. Gas can flow out of pipe 13 into accumulator 4.

Fig. 4 to 6 show a second embodiment of a 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 stream entering the housing 14 via the first port 19 flows directly into the diverter valve 3.

Other devices associated with oil separation, such as 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.

A first difference with the embodiment shown in fig. 1 is that the directional valve 3 is a 4-way valve with four ports. Two of the ports are connected to the accumulator 4 and the 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 device 9.

The accumulator 4 is provided with a heat exchanger arrangement 37, which is explained 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 is expanded into the outdoor heat exchanger 8. The refrigerant will flow from the outdoor heat exchanger 8 into the accumulator 4 and from there it will flow to the compressor 2. When the outdoor is very cold, the injection valve 38 near the liquid burst valve 39 will activate and a portion 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 may occur during very cold weather (-20 c). 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 safety 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 liquid in the piping is trapped.

A possible way of implementing such a heat exchanger arrangement 37 is shown in fig. 8.

The pipe 13 between the accumulator 4 and the casing 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 so 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-tubes 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 passage for heat exchange within accumulator 4, which extends through the interior of accumulator 4 and at least partially surrounds U-shaped tubes 25, may be referred to as an "integrated heat exchange tube". In this case, the integrated heat exchange duct is composed of the

vertical passages

43, 44 and the connection pipe 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 cross-section and can therefore be seen in fig. 10. For example, the refrigerant may enter through the first fluid port 43a, flow downward in the passage 43, further flow from the passage 43 into the passage 44 through the connection pipe 45, flow upward in the passage 44, and then flow out through the second fluid port 44 a. By switching between heating and cooling modes, the direction of flow through the integrated heat exchange tubes is reversed.

FIG. 9 shows the flow in the refrigerant gas treatment 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 switching 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. This increases the risk of liquid refrigerant reaching the compressor 2 and/or condensing in the compressor 2 if the temperature of the refrigerant flowing through the U-shaped tube 25 to the compressor is low. However, when the refrigerant that collects in the interior of the accumulator 4 and flows through the U-shaped tubes 25 is cold, it is heated by the refrigerant from the outdoor heat exchanger 8 flowing through the heat exchange tubes (inside the

passages

43, 44 and the connector 45). Thus, the integrated heat exchange tubing helps to 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, the heat exchange in the accumulator 4 enhances the 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 arriving at the accumulator 4 from the outdoor heat exchanger 8 is lower than the temperature of the liquid refrigerant flowing through the integrated heat exchange tubes within the accumulator 4 from the indoor heat exchanger 6. Therefore, also in this case, the refrigerant that has collected in the interior of the accumulator 4 and that has flowed through the U-shaped tubes 25 is heated by heat exchange within the accumulator 4. Again, the integrated heat exchange tubing helps to 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, the heat exchange in the accumulator 4 enhances the 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 portion 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, which is firmly and sealingly fixed to the housing of the accumulator 4. Thus, the block 40 may be considered to be part of the housing forming the 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 from above through the terminal flange 61 of the tube 13 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 pipe 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 receiving an upper portion of the pipe 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 an inner wall of the housing 14. An internal thread is provided at the lower end 52 of the insertion space 50 (and thus on the lower end of the inner wall 51) in the axial direction. A fixing flange 63 for detachably fixing the pipe 13 to the housing 14 is provided at an outer circumferential surface of the pipe 13. Corresponding external threads are provided at the outer circumferential surface of the fixing flange 63. Thus, the external thread of the fixing flange 63 and the internal thread at the lower end portion 52 of the insertion space 50 are engaged and thus form the threaded connection portion 60. The pipe 13 is detachably fixed to the housing 14 by this screw connection 60.

At (or at least in the vicinity of) the upper end portion 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 pipe 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 unit

16, 17 is connected to a drive shaft 18. The motor-

gearbox unit

16, 17 is 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 extends together with the motor 16 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-

unit

16, 17 is 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 engaging 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-

unit

16, 17 is also removed from the accumulator 4. This facilitates maintenance of the motor-

gearbox unit

16, 17 and replacement thereof if necessary.

If the tube 13 is fixed to the housing 14 and if the tube 13 is fixed to the accumulator 4, the housing 14, the tube 13 and the casing of the accumulator 4 form a common casing of the entire common unit. In operation, the entire interior of the common shell 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. A 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 in fluid connection with the interior of the accumulator 4.

Claims

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

characterized in that the common unit (10) is accommodated in a housing, wherein the housing can withstand at least twice the atmospheric pressure, wherein the housing comprises a housing (14) accommodating the non-return valve (11) and the reversing valve (3), an accumulator housing, and a pipe (13) connecting the housing (14) and the accumulator housing.

2. Common unit (10) according to claim 1, characterized in that the housing (14) forms a hot region and the accumulator housing forms a cold region, wherein the diverter valve (3) is connected to an actuator (16), wherein the actuator (16) is arranged in the cold region and the diverter valve (3) is arranged in the hot region, and wherein the cold region and the hot region are thermally decoupled from each other.

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

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

5. A common unit (10) according to any of claims 2-4, 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 any of claims 2-5, 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) is directly drivable by the actuator (16).

7. A utility 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 or 7, characterized in that the non-return valve (11) comprises a valve element which is radially movable with respect to the axis of rotation (12).

9. A common unit (10) according to any of claims 6 to 8, characterized in that the housing (14) in which the non-return valve (11) and the reversing valve (3) mounted together are accommodated comprises a cylindrical wall (15) surrounding the non-return valve (11) and the reversing valve (3).

10. A common unit (10) according to any of claims 6-9, characterized in that a plurality of non-return valves (11) are provided, which are distributed in circumferential direction around the axis of rotation (12).

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

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 or 12, characterized in that the oil separator (5) is arranged above the accumulator (4).

14. A common unit (10) according to any of claims 11-13, characterized in that the non-return valve (11) is arranged between the oil separator (5) and the reversing valve (3).

15. A common unit (10) according to any of claims 1-14, characterized in that the housing (14) comprises a high pressure transmitter (22) and a low pressure transmitter (23) is provided 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.