Self-regulating valve for a vapour compression system

Abstract

A valve (9) for use in a vapour compression system (1) is disclosed. The valve (9) comprises a first inlet (13) arranged to be connected to a gaseous outlet (11) of a receiver (6), a second inlet (14) arranged to be connected to an outlet of an evaporator (8), a first outlet (15) arranged to be connected to an inlet of a compressor unit (2), a non-return valve arrangement (19) arranged to allow a fluid flow from the second inlet (14) towards the first outlet (15), but to prevent a fluid flow from the first outlet (15) towards the second inlet (14), and a control valve mechanism (20) arranged to control a fluid flow from the first inlet (13) towards the first outlet (15).

Claims

1. A valve for use in a vapour compression system, the valve comprising: a first inlet arranged to be connected to a gaseous outlet of a receiver, a second inlet arranged to be connected to an outlet of an evaporator, a first outlet arranged to be connected to an inlet of a compressor unit, a non-return valve arranged to allow a fluid flow from the second inlet towards the first outlet, but to prevent a fluid flow from the first outlet towards the second inlet, and a control valve arranged to control a fluid flow from the first inlet towards the first outlet, wherein the control valve is automatically operated in response to a pressure difference between a pressure prevailing at the first inlet and a pressure prevailing at the second inlet, wherein the pressure difference acts on a movable element of the control valve to automatically operate the control valve.

2. The valve according to claim 1, wherein the control valve comprises a movable valve element of the control valve being arranged movably with respect to an opening interconnecting the first inlet and the first outlet, the position of the movable valve element relative to the opening determining an opening degree of the opening, and thereby a fluid flow from the first inlet towards the first outlet.

3. The valve according to claim 2, wherein the movable valve element is biased towards a position which defines a zero opening degree of the opening.

4. The valve according to claim 3, wherein the movable valve element is arranged to perform sliding movements relative to the opening.

5. The valve according to claim 3, wherein the non-return valve is arranged to close, thereby preventing a fluid flow from the first outlet towards the second inlet, in the case that a pressure prevailing at the first outlet exceeds a pressure prevailing at the second inlet.

6. The valve according to claim 3, wherein the non-return valve is further arranged to prevent a fluid flow from the second inlet towards the first outlet, in the case that a pressure prevailing at the first outlet exceeds a pressure prevailing at the second inlet.

7. The valve according to claim 2, wherein the movable valve element is arranged to perform sliding movements relative to the opening.

8. The valve according to claim 7, wherein the non-return valve is arranged to close, thereby preventing a fluid flow from the first outlet towards the second inlet, in the case that a pressure prevailing at the first outlet exceeds a pressure prevailing at the second inlet.

9. The valve according to claim 2, wherein the non-return valve is arranged to close, thereby preventing a fluid flow from the first outlet towards the second inlet, in the case that a pressure prevailing at the first outlet exceeds a pressure prevailing at the second inlet.

10. The valve according to claim 2, wherein the non-return valve is further arranged to prevent a fluid flow from the second inlet towards the first outlet, in the case that a pressure prevailing at the first outlet exceeds a pressure prevailing at the second inlet.

11. The valve according to claim 1, wherein the non-return valve is arranged to close, thereby preventing a fluid flow from the first outlet towards the second inlet, in the case that a pressure prevailing at the first outlet exceeds a pressure prevailing at the second inlet.

12. The valve according to claim 1, wherein the non-return valve is further arranged to prevent a fluid flow from the second inlet towards the first outlet, in the case that a pressure prevailing at the first outlet exceeds a pressure prevailing at the second inlet.

13. The valve according to claim 1, further comprising a second outlet arranged to be connected to a secondary inlet of an ejector.

14. The valve according to claim 13, further comprising a separator arranged to separate refrigerant entering the valve via the second inlet into a liquid part and a gaseous part, said separator being arranged between the second inlet, the non-return valve and the second outlet.

15. A vapour compression system comprising a compressor unit comprising one or more compressors, a heat rejecting heat exchanger, an ejector, a receiver an expansion device and an evaporator arranged in a refrigerant path, an outlet of the heat rejecting heat exchanger being connected to a primary inlet of the ejector and an outlet of the ejector being connected to the receiver, wherein the vapour compression system further comprises a valve comprising: a first inlet arranged to be connected to a gaseous outlet of the receiver, a second inlet arranged to be connected to an outlet of the evaporator, a first outlet arranged to be connected to an inlet of the compressor unit, a non-return valve arranged to allow a fluid flow from the second inlet towards the first outlet, but to prevent a fluid flow from the first outlet towards the second inlet, and a control valve arranged to control a fluid flow from the first inlet towards the first outlet, wherein the first inlet of the valve being connected to the gaseous outlet of the receiver, the second inlet of the valve being connected to the outlet of the evaporator and the first outlet of the valve being connected to the inlet of the compressor unit.

16. The vapour compression system according to claim 15, wherein the valve further comprises a second outlet, and wherein the second outlet of the valve is connected to a secondary inlet of the ejector.

17. The vapour compression system according to claim 15, wherein the control valve is automatically operated in response to a pressure difference between a pressure prevailing at the first inlet and a pressure prevailing at the second inlet.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention will now be described in further detail with reference to the accompanying drawings in which

(2) FIG. 1 is a diagrammatic view of a vapour compression system according to an embodiment of the invention,

(3) FIGS. 2-6 are cross sectional views of a valve according to a first embodiment of the invention, in various positions, and

(4) FIGS. 7-11 are cross sectional views of a valve according to a second embodiment of the invention, in various positions.

DETAILED DESCRIPTION

(5) FIG. 1 is a diagrammatic view of a vapour compression system 1 according to an embodiment of the invention. The vapour compression system 1 comprises a compressor unit 2 comprising a number of compressors 3, two of which are shown, a heat rejecting heat exchanger 4, an ejector 5, a receiver 6, an expansion device 7, in the form of an expansion valve, and an evaporator 8 arranged in a refrigerant path. The vapour compression system 1 further comprises a valve 9 according to an embodiment of the invention arranged in the refrigerant path.

(6) The receiver 6 is arranged to separate refrigerant into a liquid part and a gaseous part, and the receiver 6 comprises a liquid outlet 10 and a gaseous outlet 11. The liquid outlet 10 is connected to the expansion device 7, i.e. the liquid part of the refrigerant in the receiver 6 is supplied to the evaporator 8, via the expansion device 7.

(7) The vapour compression system 1 of FIG. 1 may be operated in the following manner. Refrigerant flowing in the refrigerant path is compressed by means of the compressors 3 of the compressor unit 2, and the compressed refrigerant is supplied to the heat rejecting heat exchanger 4. In the heat rejecting heat exchanger 4 heat exchange takes place between the refrigerant flowing through the heat rejecting heat exchanger 4 and the ambient, in such a manner that heat is rejected from the refrigerant to the ambient. In the case that the heat rejecting heat exchanger 4 is in the form of a condenser, the refrigerant is at least partly condensed, and in the case that the heat rejecting heat exchanger 4 is in the form of a gas cooler, the refrigerant is cooled, but remains in the gaseous phase.

(8) The refrigerant leaving the heat rejecting heat exchanger 4 is supplied to a primary inlet 12 of the ejector 5, where the refrigerant undergoes expansion before being supplied to the receiver 6.

(9) In the receiver 6 the refrigerant is separated into a liquid part and a gaseous part. The liquid part of the refrigerant is supplied to the expansion device 7, via the liquid outlet 10. The expansion device 7 expands the refrigerant before it is supplied to the evaporator 8. The refrigerant being supplied to the evaporator 8 is in a mixed liquid and gaseous state.

(10) The gaseous part of the refrigerant in the receiver 6 is supplied to a first inlet 13 of the valve 9, via the gaseous outlet 11 of the receiver 6.

(11) In the evaporator 8 the liquid part of the refrigerant is at least partly evaporated, while heat exchange takes place between the refrigerant and the ambient in such a manner that heat is absorbed by the refrigerant flowing through the evaporator 8. The refrigerant leaving the evaporator 8 is supplied to a second inlet 14 of the valve 9. Thus, the valve 9 receives refrigerant from the gaseous outlet 11 of the receiver 6, via the first inlet 13, and refrigerant from the evaporator 8, via the second inlet 14.

(12) The valve 9 comprises a first outlet 15 connected to an inlet of the compressor unit 2 and a second outlet 16 connected to a secondary inlet 17 of the ejector 5, via a non-return valve 18. Thus, the valve 9 supplies refrigerant to the compressors 3 of the compressor unit 2, via the first outlet 15, and refrigerant to the secondary inlet 17 of the ejector 5, via the second outlet 16.

(13) The valve 9 further comprises a non-return valve arrangement (not shown) and a control valve mechanism (not shown), as described above. Thereby the valve 9 controls refrigerant flow from the evaporator 8 and the gaseous outlet 11 of the receiver 6, respectively, and towards the compressor unit 2 and the secondary inlet 17 of the ejector 5, respectively, in a manner which will be described in further detail below with reference to FIGS. 2-6.

(14) FIGS. 2-6 are cross sectional views of a valve 9 according to a first embodiment, in various positions.

(15) The valve 9 of FIGS. 2-6 comprises a first inlet 13, a second inlet 14, a first outlet 15 and a second outlet 16. The first inlet 13 is connectable to a gaseous outlet of a receiver, the second inlet 14 is connectable to an outlet of an evaporator, the first outlet 15 is connectable to an inlet of a compressor unit, and the second outlet 16 is connectable to a secondary inlet of an ejector. Thus, the valve 9 receives refrigerant from the gaseous outlet of the receiver and from the evaporator, via the first 13 and the second 14 inlets, respectively, and supplies refrigerant to the compressor unit and to the secondary inlet of the ejector, via the first 15 and the second 16 outlets, respectively.

(16) The valve 9 further comprises a non-return valve arrangement 19 and a control valve mechanism 20. The non-return valve arrangement 19 is arranged to allow a fluid flow from the second inlet 14 towards the first outlet 15, but to prevent a fluid flow from the first outlet 15 towards the second inlet 14. Thus, the non-return valve arrangement 19 allows refrigerant received from the evaporator, via the second inlet 14, to be supplied to the inlet of the compressor unit, via the first outlet 15, but prevents refrigerant received from the gaseous outlet of the receiver, via the first inlet 13, from flowing towards the second inlet 14, and thereby a reverse flow from the first outlet 15 towards the evaporator is prevented.

(17) The control valve mechanism 20 is arranged to control the fluid flow from the first inlet 13 towards the first outlet 15. The control valve mechanism 20 comprises a movable valve element 21 arranged to perform sliding movements relative to an opening 22 interconnecting the first inlet 13 and the first outlet 15. The position of the movable valve element 21 relative to the opening 22 thereby defines a cross sectional area of a passage through which refrigerant can flow from the first inlet 13 towards the first outlet 15.

(18) A spring 23 is arranged in contact with the movable valve element 21, thereby biasing the movable valve element 21 towards a position in which the movable valve element 21 covers the entire opening 22, i.e. towards a position which defines a zero opening degree of the opening 22. The movable valve element 21 may be moved, against the biasing force provided by the spring 23, thereby opening the opening 22 and allowing a flow of refrigerant from the first inlet 13 towards the first outlet 15, when a differential pressure across the control valve mechanism 20 is sufficiently high to overcome the biasing force provided by the spring 23. This will be described further below.

(19) In FIG. 2 a pressure difference between a pressure prevailing at the first inlet 13 and a pressure prevailing at the second inlet 14 is relatively low. Thereby the differential pressure across the control valve mechanism 20 is not sufficiently high to overcome the biasing force provided by the spring 23. Accordingly, the spring 23 pushes the movable valve member 21 into the position where it covers the entire opening 22, i.e. the control valve mechanism 20 is in a closed position, and refrigerant is not allowed to pass from the first inlet 13 towards the first outlet 15.

(20) The non-return valve arrangement 19 is in an open position. Thereby refrigerant entering the valve 9 from the evaporator, via the second inlet 14, is allowed to pass through the non-return valve arrangement 19, and leave the valve 9 via the first outlet 15. Furthermore, refrigerant is also allowed to flow from the second inlet 14 towards the second outlet 16, thereby being supplied to the secondary inlet of the ejector.

(21) In FIG. 3 the pressure prevailing at the first inlet 13 is slightly higher than is the case in FIG. 2, and the differential pressure across the control valve mechanism 20 is therefore slightly higher. This has caused the movable valve element 21 to be moved slightly against the biasing force provided by the spring 23, and a small passage through the opening 22 has been opened. Accordingly, some refrigerant is allowed to pass from the first inlet 13 towards the first outlet 15.

(22) The non-return valve arrangement 19 is still in an open position, allowing a flow of refrigerant from the second inlet 14 towards the first outlet 15.

(23) In FIG. 4 the pressure prevailing at the first inlet 13 has increased further, thereby moving the movable valve element 21 a bit further against the biasing force provided by the spring 23, thereby opening the opening 22 a bit further and allowing a bit more refrigerant to pass from the first inlet 13 towards the first outlet 15. The non-return valve arrangement 19 is still in an open position.

(24) In FIG. 5 the movable valve element 21 is in the same position as in FIG. 4. The increased refrigerant flow through the opening 22, as compared to the situation illustrated in FIG. 3, has increased the pressure prevailing in a region between the opening 22 and the first outlet 15. This increase in pressure has caused the non-return valve arrangement 19 to be moved to a closed position. Thereby a flow of refrigerant from the first outlet 15 towards the second inlet 14 is prevented, i.e. refrigerant received from the gaseous outlet of the receiver, via the first inlet 13, is not allowed to flow towards the evaporator, via the second inlet 14.

(25) Furthermore, when the non-return valve arrangement 19 is in the closed position, as shown in FIG. 5, a fluid flow from the second inlet 14 towards the first outlet 15 is also prevented. Accordingly, all of the refrigerant which is received from the outlet of the evaporator, via the second inlet 14, must leave the valve 9 via the second outlet 16, and is thereby supplied to the secondary inlet of the ejector.

(26) In FIG. 6 the pressure prevailing at the first inlet 13 has increased even further, thereby moving the movable valve element 21 into a position where there is no overlap between the movable valve element 21 and the opening 22. Accordingly, the control valve mechanism 20 is in a fully open position. The non-return valve arrangement 19 is still in a closed position.

(27) In the valve 9 illustrated in FIGS. 2-6 the design of the valve 9 at the second inlet 14 is such that it operates as a separator 24. Accordingly, refrigerant entering the valve 9 via the second inlet 14 is separated into a gaseous part and a liquid part. The liquid part of the refrigerant flows towards the second outlet 16, due to gravity, and is thereby automatically supplied to the secondary inlet of the ejector. However, at least a part of the gaseous part of the refrigerant may pass through the non-return valve arrangement 19, towards the first outlet 15, thereby being supplied to the inlet of the compressor unit, to the extent that the non-return valve arrangement 19 is in an open position. Thereby it is ensured that no liquid refrigerant is supplied to the inlet of the compressor unit, even if liquid refrigerant is allowed to pass through the evaporator.

(28) FIGS. 7-11 are cross sectional views of a valve 9 according to a second embodiment, in various positions. The valve 9 of FIGS. 7-11 is very similar to the valve 9 of FIGS. 2-6, and it will therefore not be described in detail here.

(29) The valve 9 of FIGS. 7-11 is not provided with a second outlet. Thus, all of the refrigerant which enters the valve 9, via the first inlet 13 and via the second inlet 14, must leave the valve 9 via the first outlet 15, and is thereby supplied to the inlet of the compressor unit. Instead the refrigerant path may advantageously comprise a branch arranged between the outlet of the evaporator and the second inlet 15 of the valve 9, providing a fluid passage from the outlet of the evaporator to a secondary inlet of an ejector.

(30) The positions of the control valve mechanism 20 and the non-return valve arrangement 19 of FIG. 7 correspond to the positions of the control valve mechanism 20 and the non-return valve arrangement 19 of FIG. 2. The positions of the control valve mechanism 20 and the non-return valve arrangement 19 of FIG. 8 correspond to the positions of the control valve mechanism 20 and the non-return valve arrangement 19 of FIG. 3. The positions of the control valve mechanism 20 and the non-return valve arrangement 19 of FIG. 9 correspond to the positions of the control valve mechanism 20 and the non-return valve arrangement 19 of FIG. 4. The positions of the control valve mechanism 20 and the non-return valve arrangement 19 of FIG. 10 correspond to the positions of the control valve mechanism 20 and the non-return valve arrangement 19 of FIG. 5. The positions of the control valve mechanism 20 and the non-return valve arrangement 19 of FIG. 11 correspond to the positions of the control valve mechanism 20 and the non-return valve arrangement 19 of FIG. 6.

(31) While the present disclosure has been illustrated and described with respect to a particular embodiment thereof, it should be appreciated by those of ordinary skill in the art that various modifications to this disclosure may be made without departing from the spirit and scope of the present disclosure.