JP7278459B2 - Electronic expansion valve and its cooling system - Google Patents

Description

TECHNICAL FIELD The present invention relates to the technical field of cooling, and more particularly to an electronic expansion valve and its cooling system.

The electronic expansion valve is the main component of the inverter air conditioner, and it can adjust the amount of liquid supplied to the heat exchanger according to the preset program, which is an important part for making the cooling system intelligent. , is also an important means and guarantee for the optimization of the cooling system to be truly realized.

A conventional electronic expansion valve generally includes a valve seat and a nut assembly interposed within the valve seat and including a nut seat. It affects the realization of the function of

Based on this, the present invention provides an electronic expansion valve for the problem that the nut seat tends to rotate. Technical aspects are as follows.

An electronic expansion valve including a valve seat and a nut assembly at least partially inserted into the valve seat, the nut assembly surrounding the nut seat and connecting to the nut seat. a connecting sleeve, wherein the connecting sleeve is provided with a rotation stop, the rotation stop being capable of engaging the valve seat to limit circumferential rotation of the connecting sleeve and the nut seat.

By providing in this way, the anti-rotation portion engages with the valve seat to limit the position, so that the rotation of the connecting sleeve can be prevented. To limit the seat and avoid the problem of rotating the nut seat to affect the realization of the function of the electronic expansion valve.

In one embodiment, the hardness of the valve seat is less than the hardness of the connecting sleeve, and the valve seat is engaged with the connecting sleeve with an interference fit.

By providing in this way, after the nut seat and the connecting sleeve are pushed into the valve seat with an interference fit, the valve seat deforms in accordance with the shape of the connecting sleeve and engages with the rotation-stopping portion to realize the rotation-stopping function. A possible shape is formed.

In one embodiment, the rotation stop comprises a first rotation stop, the outer surface of the connecting sleeve comprises a first surface and a second surface, the first surface being planar and the second surface A first rotation stopper is formed at the boundary between the first surface and the second surface.

By providing in this way, an edge-like structure is formed between the flat surface and the arc surface, and after the inner wall of the valve seat is slightly deformed, the edge-like structure tends to form anti-rotation engagement with the valve seat. .

In one embodiment, the anti-rotation part comprises a first anti-rotation part, the outer surface of the connecting sleeve comprises a first surface and a second surface, both the first surface and the second surface being arcuate surfaces. , the first surface and the second surface are not concentric, the first surface is connected to the second surface, and a first rotation stop is formed at the boundary between the first surface and the second surface.

In one embodiment, the anti-rotation part includes a second anti-rotation part, a first groove is drilled in the side surface of the connecting sleeve, and the interface between the inner wall of the first groove and the outer wall of the connecting sleeve is A second anti-rotation part is formed and/or a second groove is bored in the end surface of the connecting sleeve remote from the valve seat, and the boundary portion between the inner wall of the second groove and the outer wall of the connecting sleeve is formed with a second rotation stop. By so providing, a single groove can form a plurality of edge-like structures with the outer wall of the connecting sleeve, enhancing the anti-rotation function of the connecting sleeve.

In one embodiment, the electronic expansion valve further includes a socket attached to the valve seat and having a valve chamber therein, and the nut assembly further includes a screw inserted into and screwed into the nut seat. , the nut seat is provided with a balancing hole, the end surface of the connecting sleeve remote from the valve seat is drilled with a second groove, the balancing hole is provided through the second groove, the inside of the nut seat is It communicates with the valve chamber through the balancing hole and the second groove.

With this arrangement, the groove and the equalizing hole are communicated through, achieving the purpose of balancing the pressure inside and outside the nut seat.

In one embodiment, the electronic expansion valve further includes a socket attached to the valve seat and having a valve chamber therein, and the nut assembly further includes a screw inserted into and screwed into the nut seat. , an equalizing hole is drilled in the outer wall of the nut seat, the equalizing hole is located on the side of the connecting sleeve away from the valve seat, the connecting sleeve does not shield the equalizing hole, and the inside of the nut seat is balanced It communicates with the valve chamber through the opening.

With this provision, the balancing hole is directly communicated with the outer chamber of the nut seat, and the connecting sleeve does not need to be further provided with a recess through the balancing hole, thus simplifying the structure. .

In one embodiment, the connecting sleeve is provided with a projection which is provided perpendicularly to the connecting sleeve and fitted into the nut seat.

This provision increases the strength of the connection between the connecting sleeve and the nut seat.

In one embodiment, the connecting sleeve is made of stainless steel or powder metallurgical material.

By providing in this way, the strength of the connecting sleeve is ensured and the cost is low.

The present invention further provides the following technical aspects.

The cooling system includes the stop valve described above.

Compared with the prior art, in the stop valve provided by the present invention, the anti-rotation part can be engaged with the valve seat to limit the position to prevent the rotation of the connecting sleeve, and the connecting sleeve and the nut can be prevented from rotating. The connection with the seat restricts the nut seat in the circumferential direction to avoid the problem of the nut seat rotating and affecting the realization of the function of the electronic expansion valve.

1 is a cross-sectional view of an electronic expansion valve provided by the present invention; FIG. 1 is a perspective view of one embodiment of a nut assembly provided by the present invention; FIG. FIG. 3 is a perspective view of another embodiment of a nut assembly provided by the present invention; 1 is a perspective view of a connecting sleeve provided by the present invention; FIG. FIG. 1 is a perspective view 1 of Embodiment 3 of a connecting sleeve provided by the present invention; Fig. 2 is a perspective view 2 of Embodiment 3 of the connecting sleeve provided by the present invention; 1 is a perspective view of Embodiment 1 of a connecting sleeve provided by the present invention; FIG.

In the drawings, each symbol has the following meaning.
REFERENCE SIGNS LIST 100 electronic expansion valve 10 valve seat 11 first opening 12 second opening 13 first communication pipe 14 second communication pipe 15 valve port 20 valve core assembly 21 valve core 22 elastic member 24 magnetism Rotor 25 First connecting rod 30 Nut assembly 31 Nut seat 311 Balancing hole 32 Connection sleeve 321 First rotation stopper 322 Second rotation stopper 323 Protrusion 324 First concave groove 325 Second concave groove 326 First surface 327 Second surface 33 Screw 40 Stopper assembly 41 Second connecting rod 42 Guide member 43 First stop block 44 Second stop block 50 Socket 51 End cover , 52 valve chambers.

In the following, the drawings in the embodiments of the present invention are combined to describe the technical aspects of the embodiments of the present invention clearly and completely. is clearly not an embodiment of Based on the embodiments in the present invention, all other embodiments obtained by persons skilled in the art without creative efforts shall fall within the protection scope of the present invention.

It should be noted that when an assembly is said to be "attached to" another assembly, it may reside directly on the other assembly, or there may be assemblies in between. good too. Where an assembly is considered to be "provided" on another assembly, it may be provided directly on top of the other assembly, or there may be assemblies in between at the same time. Where an assembly is considered "fixed" to another assembly, it may be fixed directly onto the other assembly, or there may be assemblies in between at the same time.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the specification of the present invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the listed elements.

Referring to FIGS. 1 to 3, such an electronic expansion valve 100 is installed in a cooling system and used to realize pipeline communication and disconnection.

Electronic expansion valve 100 includes valve seat 10 , socket 50 , valve core assembly 20 and nut assembly 30 . A socket 50 is connected to the valve seat 10 and is used to provide a sealed space for the electronic expansion valve 100 , has a valve chamber 52 within the socket 50 , and one end of the valve core assembly 20 is inserted into the valve seat 10 . The nut assembly 30 is positioned at least partially within the valve chamber 52 and engages the valve core assembly 20 axially along the socket 50 . can be moved.

Specifically, the valve seat 10 is provided with a first opening 11 , a second opening 12 and a valve port 15 , and the second opening 12 communicates with the valve port 15 . In this embodiment, when the electronic expansion valve 100 is vertically mounted as shown in the drawings of the specification (up, down, left, right, etc., all of the electronic expansion valves 100 are vertically mounted state is acquiesced and will not be described below).

A first communication pipe 13 is connected to the side of the first opening 11 away from the valve core assembly 20, and the first opening 11 is communicated with the pipeline of the cooling system by the first communication pipe 13. A second communication pipe 14 is connected to the side remote from the valve core assembly 20 , and the second opening 12 is communicated with the pipeline of the cooling system through the second communication pipe 14 . The first communicating pipe 13 and the second communicating pipe 14 are used as the inlet and outlet of the medium, respectively.

When the first communicating pipe 13 is used as the inlet of the medium, the medium flows from the first communicating pipe 13 into the electronic expansion valve 100, passes through the first opening 11, enters the valve seat 10, and enters the electronic expansion valve 100. is opened, the medium passes through the valve port 15 and flows out of the electronic expansion valve 100 via the second communicating pipe 14 . vice versa, the medium enters the valve seat 10 through the second opening 12 from the second communicating pipe 14, passes through the valve opening 15 and the first communicating pipe 13, and flows out of the electronic expansion valve 100. may

Optionally, the positions of the first opening 11 and the second opening 12 are not limited to being drilled below and to the left of the valve seat 10 in this embodiment. In other embodiments, the first opening 11 and the second opening 12 may be provided on the lower side and right side of the valve seat 10, and so on.

An end cover 51 is provided at one end of the socket 50 away from the valve seat 10 , and the end cover 51 is connected to the socket 50 to seal the end of the socket 50 . sealed. Optionally, an end cover 51 may be fitted around the outer end of the socket 50 remote from the valve seat 10 to provide a seal, and close to the end of the socket 50 remote from the valve seat 10 to provide a seal. It may be provided inside and the outer peripheral side of the end cover 51 may be brought into contact with the inner wall of the socket 50 . The method of connecting the end cover 51 and the socket 50 is not limited to the above-described individual modes, and any method may be used as long as the function of sealing the electronic expansion valve 100 can be achieved.

A stopper assembly 40 is connected to the inner wall of the end cover 51 and is used to stop unlimited upward movement of the valve core assembly 20 and to stop unlimited downward movement of the valve core assembly 20 . Acts as an upper or lower limiting action.

Specifically, the stopper assembly 40 includes a guide member 42, a second connecting rod 41, a first stopping block 43 and a second stopping block 44, one end of the second connecting rod 41 abuts the nut assembly 30, and the other end is fitted in the guide member 42, the outer wall of the guide member 42 is helical, and the first stop block 43 and the second stop block 44 are located at both ends of the guide member 42, respectively.

In the operation process, when the electronic expansion valve 100 is in the valve opening operation state, the nut assembly 30 rotates and rises, and the second connecting rod 41 abuts against the nut assembly 30 , so that the nut assembly 30 also pushes the second connecting rod 41 . The rotation axis of the second connecting rod 41 is coaxial with the guide member 42 so as to be rotated and raised in conjunction with each other. When the second connecting rod 41 rises to the topmost end of the guide member 42, it is restricted by the first stop block 43 and cannot continue to rise, thereby also stopping the rotational upward movement of the nut assembly 30, and the second connecting rod 41 Once the rod 41 has descended to the bottom end of the guide member 42, it is restricted by the second stop block 44 and cannot continue to descend, thereby also stopping the rotational downward movement of the nut assembly 30.

Nut assembly 30 includes nut seat 31 , screw 33 and connecting sleeve 32 . At least part of the nut seat 31 is engaged with the outer peripheral side of the valve core assembly 20 , the screw 33 is provided in the nut seat 31 and screwed into the nut seat 31 , and the screw 33 is connected to the valve core assembly 20 . . One end of the nut seat 31 remote from the end cover 51 is inserted into the valve seat 10 . The connecting sleeve 32 surrounds and is connected to the nut seat 31 , and the assembly formed by the nut seat 31 and the connecting sleeve 32 engages the valve seat 10 with an interference fit.

The nut seat 31 is made of engineering plastics, the connecting sleeve 32 is made of metal or powder metallurgy material, and the connecting sleeve 32 serves to protect the nut seat 31 . The nut seat 31 is made of engineering plastics and can be molded by injection molding, and the quality of the threads in the nut seat 31 can be ensured during the injection molding process. The connection sleeve 32 is made of metal or powder metallurgy. The connecting sleeve 32 protects the nut seat 31 from damage and protects the integrity of the nut seat 31 when it is engaged with the valve seat 10 with an interference fit because it is made of a hard metal or powder metallurgical material. can be ensured. The nut seat 31 and the connecting sleeve 32 are fixedly connected by injection molding.

Specifically, a balancing hole 311 is bored in the nut seat 31 and used to balance the pressure inside the nut seat 31 and the valve chamber 52 .

Referring to FIG. 3, in one embodiment, the balancing hole 311 is provided in the outer wall of the nut seat 31, and the balancing hole 311 is located on the side of the connecting sleeve 32 remote from the valve seat 10, i.e. the connecting sleeve 32 does not block the balancing hole 311, but achieves communication between the inside and outside of the nut seat 31, so that the pressure above and below the screw 33 is balanced. Prevents becoming unable to move or becoming difficult to move.

Referring to FIG. 2, in another embodiment, the balancing hole 311 is drilled in the area covered by the inner wall of the connecting sleeve 32 and has a second recess on the end face of the connecting sleeve 32 remote from the valve seat 10 . A groove 325 is formed, the second groove 325 is provided through the balancing hole 311 , and the inside of the nut seat 31 communicates with the valve chamber 52 through the balancing hole 311 and the second groove 325 . be done.

A first connecting rod 25 is provided on the screw 33, and the first connecting rod 25 is connected to one end of the screw 33 remote from the valve seat 10, and engages with a second connecting rod 41 to move the screw 33 axially. used to limit

The hardness of the connecting sleeve 32 is greater than the hardness of the valve seat 10, so as to ensure that the connecting sleeve 32 undergoes little or almost no deformation when the connecting sleeve 32 is pressed into the valve seat 10 with an interference fit. .

In one embodiment, the connecting sleeve 32 has an annular shape, and the annular connecting sleeve 32 surrounds the outside of the nut seat 31 .

In another embodiment, the connecting sleeve 32 is elongated and there are a plurality of connecting sleeves 32 , the plurality of connecting sleeves 32 surrounding the outside of the nut seat 31 .

Specifically, the connection sleeve 32 is provided with a rotation stopper, and the rotation stopper engages with the valve seat 10 to limit the rotation of the connection sleeve 32 in the circumferential direction. Rotation can be restricted. Since the hardness of the connecting sleeve 32 is greater than the hardness of the valve seat 10, this provision ensures that when the connecting sleeve 32 is inserted into the valve seat 10, the valve seat 10 is engaged with the connecting sleeve 32 with an interference fit. , and deforms in accordance with the shape of the connecting sleeve 32 to be in close contact with the connecting sleeve 32 . Since the hardness of the connecting sleeve 32 is likewise greater than that of the nut seat 31, the nut seat 31 and the connecting sleeve 32 are engaged with each other with an interference fit to achieve a tighter connection.

Further, referring to FIG. 7, in Embodiment 1, the detent includes a first detent 321, the outer surface of the connecting sleeve 32 includes a first surface 326 and a second surface 327, and the first surface 326 is provided as a flat surface, the first surface 326 and the second surface 327 are connected, and the first rotation stopper 321 is formed at the boundary between the first surface 326 and the second surface 327 . When the connecting sleeve 32 is inserted into the valve seat 10 , the connecting sleeve 32 is engaged with the valve seat 10 with an interference fit, and the valve seat 10 is pressed against the edge of the interface between the first surface 326 and the second surface 327 . It deforms according to its shape to engage with the first rotation stop 321 to limit the rotation of the connecting sleeve 32 .

The outer surface of the connecting sleeve 32 may further include a third surface and a fourth surface, the third surface being a plane and the fourth surface being an arc, that is, the outer surface of the connecting sleeve 32 is two planes. are provided at intervals, and two arcuate surfaces are provided between the two planes, and the combination of the outer plane and the arcuate surface of the connecting sleeve 32 is the above-mentioned one plane and one arc in this embodiment. It can be understood that it should not be limited to combinations with planes or combinations of two planes and two arcs.

In the second embodiment, both the first surface 326 and the second surface 327 of the connecting sleeve 32 are provided as arcuate surfaces, and the arcuate surfaces of the first surface 326 and the second surface 327 are not concentric, and the first surface 326 and The second surface 327 is connected, and the first rotation stopping portion 321 is formed at the boundary between the two.

Optionally, the outer side of the connecting sleeve 32 can be further provided with a third surface, the third surface is also an arc surface, and the combination of the outer arc surfaces of the connecting sleeve 32 is the two arc surfaces in this embodiment. should not be limited to combinations of

In the third embodiment, referring to FIGS. 5 to 6, the connecting sleeve 32 is bored with a first groove 324, and the inner wall of the first groove 324 in the connecting sleeve 32 and the outer wall of the connecting sleeve 32 are separated. A second rotation stop 322 is formed at the boundary portion and, as described above, when the connecting sleeve 32 is inserted into the valve seat 10, the second rotation stop 322, like the first rotation stop 321, is the valve seat. It can engage the seat 10 to limit the rotation of the connecting sleeve 32 . Alternatively, the second anti-rotation part 322 is formed at the boundary between the inner wall of the second groove 325 and the outer wall of the connecting sleeve 32, or the connecting sleeve 32 has the first groove 324 and the second groove at the same time. A groove 325 is provided, and a second anti-rotation portion 322 is formed at the interface between the first groove 324 and the second groove 325 and the outer wall of the connecting sleeve 32 respectively.

Optionally, referring to FIG. 4 , in Embodiment 1 and Embodiment 2, or in a combination of Embodiment 1 and Embodiment 2, the side surface of the connecting sleeve 32 also has one or more first grooves 324 . It may be drilled, and the drilling of the first groove 324 does not affect the arrangement of the plane and the arc surface in the above embodiments. Alternatively, one or more second grooves 325 are drilled in the end surface of the connecting sleeve 32 away from the valve seat 10 so that the balancing hole 311 and the valve chamber 52 can communicate with each other. It is provided through the balancing hole 311 .

The connecting sleeve 32 is provided with a projection 323 fitted in the nut seat 31 and used to reinforce the connection between the connecting sleeve 32 and the nut seat 31 .

Preferably, in this embodiment, the included angle between the connecting sleeve 32 and the protrusion 323 is a right angle. In other embodiments, the included angle between the connecting sleeve 32 and the protrusion 323 may be obtuse or acute.

The valve core assembly 20 includes a valve core 21 and an elastic member 22, and the valve core 21 is used to insert into the valve port 15 so that flow control of the electronic expansion valve 100 is achieved. The screw 33 and the valve core 21 are rotationally connected, the elastic member 22 is provided inside the screw 33 , one end of the elastic member 22 contacts the valve core 21 and the other end contacts the screw 33 . When the valve core 21 is inserted into the valve opening 15 , the elastic member 22 can act to cushion the screw 33 and the valve core 21 .

The electronic expansion valve 100 further includes a magnetic rotor 24 connected to the top outer wall of the screw 33 away from the valve seat 10 such that when an electromagnetic coil (not shown) is energized to produce a magnetic field, the magnetic rotor 24 is driven to rotate, the screw 33 is rotated in conjunction with it, and the nut seat 31 does not rotate after being limited by the stopper portion, so that the screw 33 interlocks with the valve core 21 to achieve lifting motion. do. Alternatively, valve core assembly 20 may select other drive members, so long as they are capable of driving rotation of valve core assembly 20 .

The present invention further provides a cooling system including an electronic expansion valve 100 as described above, which is mounted in a medium passageway of the cooling system to control the flow rate of the passageway.

In the operation process of the electronic expansion valve 100, when the electronic expansion valve 100 needs to be opened wide, the rotation of the magnetic rotor 24 is driven by an external electromagnetic coil to rotate the screw 33 in conjunction with the rotation of the screw 33. The threaded engagement with the seat 31 raises the valve core 21 in conjunction, the first connecting rod 25 of the screw 33 hits the second connecting rod 41, and the second connecting rod 41 follows the guide path of the guide member 42. When it rises and reaches the apex, it stops the upward movement, thereby stopping the upward movement of the valve core 21 as well. When the electronic expansion valve 100 needs to be opened slightly, the electromagnetic coil is reversely energized so that the magnetic rotor 24 is rotated in the opposite direction, finally realizing the descent of the valve core 21, and the valve core 21 is the valve mouth. 15, the gap between the valve core 21 and the inner wall of the valve port 15 is reduced, thereby reducing the flow rate of the medium.

Compared with the prior art, the anti-rotation part of the present invention can engage the valve seat 10 to limit the position to prevent the connection sleeve 32 from rotating, and furthermore, the connection sleeve 32 and the nut seat 31 are connected together. This connection restricts the nut seat 31 in the circumferential direction, thereby avoiding the problem of the rotation of the nut seat 31 affecting the realization of the function of the electronic expansion valve 100 .

Each technical feature of the above-described embodiments can be arbitrarily combined, and in order to simplify the description, not all possible combinations of each technical feature of the above-described embodiments are described. Unless there is a contradiction in the combination of features, the ranges described herein should be considered.

Although the above examples merely represent some embodiments of the present invention, and the description is more specific and detailed, they should not be taken as limitations on the scope of the invention. It should be noted that many variations and improvements can be made by those skilled in the art without departing from the concept of the invention, which are covered by the claims of the invention. Accordingly, the scope of the present invention shall be subject to the appended claims.

Claims (10)

An electronic expansion valve comprising a valve seat (10) and a nut assembly (30) at least partially interposed within said valve seat (10), comprising:
The nut assembly (30) includes a nut seat (31) and a connection sleeve (32) surrounding the outer peripheral side of the nut seat (31) and connected to the nut seat (31). 32) is provided with a rotation stop, which engages with the valve seat (10) to limit the circumferential rotation of the connecting sleeve (32) and the nut seat (31). electronic expansion valve. Electroexpansion according to claim 1, wherein the hardness of the valve seat (10) is less than the hardness of the connecting sleeve (32), and the valve seat (10) is engaged with the connecting sleeve (32) with an interference fit. valve. Said anti-rotation part comprises a first anti-rotation part (321), said outer surface of said connecting sleeve (32) comprises a first surface (326) and a second surface (327), said first surface ( 326) is a plane and is connected to the second surface (327), and the first rotation stopper (321) is located at the boundary between the first surface (326) and the second surface (327). 3. The electronic expansion valve of claim 2 formed. Said anti-rotation part comprises a first anti-rotation part (321), said outer surface of said connecting sleeve (32) comprises a first surface (326) and a second surface (327), said first surface ( 326) and said second surface (327) are both arcuate surfaces, said first surface (326) and said second surface (327) are not concentric, said first surface (326) is said second surface 3. The electronic expansion according to claim 2, wherein said first rotation stopper (321) is formed at a boundary portion between said first surface (326) and said second surface (327). valve. The anti-rotation part includes a second anti-rotation part (322), a first groove (324) is drilled on the side of the connection sleeve (32), and the inner wall of the first groove (324) is connected to the connection. The second rotation stopper (322) is formed at the boundary between the outer wall of the sleeve (32) and/or the end surface of the connection sleeve (32) away from the valve seat has a second groove. (325) is drilled, and the second anti-rotation part (322) is formed at the boundary between the inner wall of the second groove (325) and the outer wall of the connecting sleeve (32). 5. The electronic expansion valve according to Item 2, 3 or 4. The electronic expansion valve further includes a socket (50) attached to the valve seat (10) and having a valve chamber (52) therein, and the nut assembly (30) is inserted into the nut seat (31). further comprising a screw (33) provided and screwed into said nut seat (31), said nut seat (31) being provided with a balancing hole (311), from said valve seat in said connecting sleeve (32). A second groove (325) is drilled in the remote end face, the balancing hole (311) is provided through the second groove (325), and the inside of the nut seat (31) is the balance 2. The electronic expansion valve according to claim 1, wherein the valve chamber (52) is communicated with through the opening (311) and the second groove (325). The electronic expansion valve further includes a socket (50) attached to the valve seat (10) and having a valve chamber (52) therein, and the nut assembly (30) is inserted into the nut seat (31). further comprising a screw (33) provided and screwed into the nut seat (31), a balancing hole (311) drilled in the outer wall of the nut seat (31), the balancing hole (311) is located on the side of the connecting sleeve (32) away from the valve seat (10), the connecting sleeve (32) does not block the balancing hole (311) and the inside of the nut seat (31) is communicated with the valve chamber (52) by the balancing hole (311). 2. The electronic expansion according to claim 1, wherein the connecting sleeve (32) is provided with a protrusion (323) that is provided perpendicularly to the connecting sleeve (32) and is fitted into the nut seat (31). valve. Electronic expansion valve according to claim 1, wherein the connecting sleeve (32) is made of stainless steel or a powder metallurgical material. A cooling system comprising an electronic expansion valve according to any one of claims 1-9.

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