Vapor-compression-type refrigerating machine

Abstract

The internal heat exchanger 7 is provided which exchanges heat between the refrigerant of low pressure and the refrigerant of high pressure, and the pre-load adjusting mechanism of the expansion valve 5 is abolished. Due to the above structure, the refrigerant flowing into the expansion valve 5 is cooled in the internal heat exchanger 7 , and enthalpy of the refrigerant flowing into the evaporator 6 is reduced. On the contrary, the refrigerant sucked into the compressor 1 is heated. Accordingly, a difference in enthalpy between the refrigerant at the inlet and the refrigerant at the outlet of the evaporator 6 can be made large, and the heat absorbing capacity of the evaporator 6 can be enhanced, and further it becomes possible to give the degree of superheat to the refrigerant sucked into the compressor 1 . Therefore, even if the pre-load adjusting mechanism is abolished, the vapor-compression-type refrigerating machine can be stably operated.

1. A vapor-compression-type refrigerating machine for moving heat from a portion on the low temperature side to a portion on the high temperature side, comprising:
 a compressor for sucking and compressing refrigerant; 
 a radiator for radiating heat from the refrigerant of high pressure; 
 an expansion valve for decompressing and expanding the refrigerant cooled by the radiator; 
 an evaporator for evaporating the refrigerant decompressed by the expansion valve so that heat can be absorbed by the refrigerant; and 
 an internal heat exchanger for exchanging heat between the refrigerant of high pressure before the decompression by the expansion valve and the refrigerant of low pressure to be sucked by the compressor, 
 the expansion valve including: 
 a thin film-like diaphragm forming an airtightly closed space into which a predetermined mass of gas is enclosed; 
 a valve body for changing a degree of throttle opening being interlocked with a displacement of the diaphragm; 
 a spring for giving an elastic force to the valve body in a direction so that a volume of the airtightly closed space can be reduced, from an opposite side of the diaphragm to the side of the diaphragm on which the airtightly closed space is located; and 
 a load giving portion for giving an initial load to the spring, wherein 
 pressure in the airtightly closed space changes according to the temperature of the refrigerant flowing out from the evaporator, pressure of the refrigerant flowing out from the evaporator acts on an opposite side of the diaphragm to the side of the diaphragm on which the airtightly closed space is located, and the load giving portion can not be moved with respect to the housing. 
 
     
     
       2. A vapor-compression-type refrigerating machine according to  claim 1 , wherein the internal heat exchanger is a double tube composed of an inner cylindrical tube and outer cylindrical tube. 
     
     
       3. A vapor-compression-type refrigerating machine according to  claim 1 , wherein the expansion valve is accommodated in a piping means composing a refrigerant passage in which the refrigerant at low pressure flows. 
     
     
       4. A vapor-compression-type refrigerating machine according to  claim 3 , wherein the expansion valve is fixed so that it can be elastically displaced in the piping means. 
     
     
       5. A vapor-compression-type refrigerating machine according to  claim 1 , wherein the internal heat exchanger and the expansion valve are integrated with each other into one body. 
     
     
       6. A vapor-compression-type refrigerating machine for moving heat from a portion on the low temperature side to a portion on the high temperature side, comprising:
 a compressor for sucking and compressing refrigerant; 
 a radiator for radiating heat from the refrigerant of high pressure; 
 an expansion valve for decompressing and expanding the refrigerant cooled by the radiator; 
 an evaporator for evaporating the refrigerant decompressed by the expansion valve so that heat can be absorbed by the refrigerant; and 
 an internal heat exchanger for exchanging heat between the refrigerant of high pressure before the decompression by the expansion valve and the refrigerant of low pressure to be sucked by the compressor, 
 the expansion valve including: 
 a thin film-like diaphragm forming an airtightly closed space into which a predetermined mass of gas is enclosed; and 
 a valve body for changing a degree of throttle opening being interlocked with a displacement of the diaphragm, wherein 
 pressure in the airtightly closed space changes according to the temperature of the refrigerant flowing out from the evaporator, pressure of the refrigerant flowing out from the evaporator acts on an opposite side of the diaphragm to the side of the diaphragm on which the airtightly closed space is located, and the diaphragm is displaced only by a difference in pressure between the airtightly closed space and the refrigerant flowing out from the evaporator. 
 
     
     
       7. A vapor-compression-type refrigerating machine according to  claim 6 , wherein the connecting rod for connecting the diaphragm with the valve body is joined to the diaphragm and, further;
 the connecting rod is joined to the valve body. 
 
     
     
       8. A vapor-compression-type refrigerating machine according to  claim 6 , wherein a diaphragm case for supporting the diaphragm from the opposite side to the side, on which the airtightly closed space is located, is integrated with the housing, in which the valve seat is formed, by means of integral forming or joining. 
     
     
       9. A vapor-compression-type refrigerating machine according to  claim 6 , wherein the internal heat exchanger is a double tube composed of an inner cylindrical tube and outer cylindrical tube. 
     
     
       10. A vapor-compression-type refrigerating machine according to  claim 6 , wherein the expansion valve is accommodated in a piping means composing a refrigerant passage in which the refrigerant at low pressure flows. 
     
     
       11. A vapor-compression-type refrigerating machine according to  claim 10 , wherein the expansion valve is fixed so that it can be elastically displaced in the piping means. 
     
     
       12. A vapor-compression-type refrigerating machine according to  claim 6 , wherein the internal heat exchanger and the expansion valve are integrated, with each other, into one body. 
     
     
       13. The vapor-compression-type refrigerating machine according to claim 1, wherein the expansion valve regulates an amount of refrigerant supplied to the evaporator to adjust a state of refrigerant flowing between the evaporator and the internal heat exchanger within a range between a dryness X=0.9 and a superheat SH=5° C. 
     
     
       14. The vapor-compression-type refrigerating machine according to claim 13, wherein the state of refrigerant is adjusted within a range between a dryness X=0.9 and a superheat SH=0° C. 
     
     
       15. The vapor-compression-type refrigerating machine according to claim 13, wherein the state of refrigerant is adjusted within a range between a superheat SH=0° C. and a superheat SH=5° C. 
     
     
       16. The vapor-compression-type refrigerating machine according to claim 6, wherein the expansion valve regulates an amount of refrigerant supplied to the evaporator to adjust a state of refrigerant flowing between the evaporator and the internal heat exchanger within a range between a dryness X=0.9 and a superheat SH=5° C. 
     
     
       17. The vapor-compression-type refrigerating machine according to claim 16, wherein the state of refrigerant is adjusted within a range between a dryness X=0.9 and a superheat S=0° C. 
     
     
       18. The vapor-compression-type refrigerating machine according to claim 16, wherein the state of refrigerant is adjusted within a range between a superheat SH=0° C. and a superheat SH=5° C. 
     
     
       19. A vapor-compression-type refrigerating machine for moving heat from a portion on a low temperature side to a portion on a high temperature side, comprising:
 a compressor for sucking and compressing refrigerant;   a radiator for radiating heat from the refrigerant of high pressure;   an expansion device disposed between a high pressure side and a low pressure side of the vapor-compression-type refrigerating machine, the expansion device having a passage in which the refrigerant cooled by the radiator flows;   an evaporator for evaporating the refrigerant decompressed by the expansion device so that heat can be absorbed by the refrigerant; and   an internal heat exchanger disposed between a high pressure passage to the expansion device and a low pressure passage from the evaporator to provide heat exchange between the refrigerant of high pressure before the decompression by the expansion device and the refrigerant of low pressure to be sucked by the compressor, wherein   the expansion device regulates an amount of refrigerant supplied to the evaporator to adjust a state of refrigerant flowing between the evaporator and the internal heat exchanger within a range between a dryness X=0.9 and a superheat SH=5° C.;   the expansion valve comprises a throttle portion having a variable opening; and   the variable opening of the throttle portion is variable based on a differential pressure between a pressure of gas in an airtightly closed space, the volume of the closed space being variable based on a temperature of the refrigerant flowing from the evaporator to the internal heat exchanger and a pressure of the refrigerant flowing from the evaporator to the internal heat exchanger.   
     
     
       20. The vapor-compression-type refrigerating machine according to claim 19, wherein the state of refrigerant is adjusted within a range between a dryness X=0.9 and a superheat SH=0° C. 
     
     
       21. The vapor-compression-type refrigerating machine according to claim 19, wherein the state of refrigerant is adjusted within a range between a superheat SH=0.0 and a superheat SH=5° C. 
     
     
       22. The vapor-compression-type refrigerating machine according to claim 19, wherein the internal heat exchanger is a double tube including an inner tube and an outer tube. 
     
     
       23. The vapor-compression-type refrigerating machine according to claim 19, wherein the expansion device is accommodated in a piping providing a refrigerant passage in which the refrigerant at low pressure flows. 
     
     
       24. The vapor-compression-type refrigerating machine according to claim 23, wherein the expansion device is fixed so that it can be elastically displaced in the piping. 
     
     
       25. The vapor-compression-type refrigerating machine according to claim 19, wherein the internal heat exchanger and the expansion device are integrated with each other into one body. 
     
     
       26. An expansion device for a vapor-compression-type refrigerating cycle, the expansion device comprising:
 a throttle portion of which an opening is variable, the throttle portion receiving refrigerant from an internal heat exchanger disposed between a high pressure passage to the expansion device and a low pressure passage from an evaporator to provide heat exchange therebetween; and   a temperature detecting portion defining a chamber of which volume varies in response to a temperature indicative of a state of refrigerant and actuates the throttle portion, wherein   the throttle portion and the temperature detecting portion are adjusted to regulate amount of refrigerant to adjust the state of refrigerant flowing between the evaporator and the internal heat exchanger within a range between a dryness X=0.9 and a superheat SH=5° C.; and   the variable opening of the throttle portion is variable based on a differential pressure between a pressure of gas in the chamber, the volume of the chamber based on a temperature of the refrigerant flowing from the evaporator to the internal heat exchanger and a pressure of the refrigerant flowing from the evaporator to the internal heat exchanger.   
     
     
       27. The expansion device according to claim 26, wherein the throttle portion and the temperature detecting portion are adjusted to adjust the state of refrigerant within a range between a dryness X=0.9 and a superheat SH=0° C. 
     
     
       28. The expansion device according to claim 26, wherein the throttle portion and the temperature detecting portion are adjusted to adjust the state of refrigerant within a range between a superheat SH=0° C. and a superheat SH=5° C. 
     
     
       29. The expansion device according to claim 26, further comprising a housing enabling direct connection with the internal heat exchanger.