Pressure Control Valve

Abstract

In a pressure controlling valve 3 for causing deformation of a resilient member 32 by a pressure difference between a CO 2 gas pressure in a sealed space (heat sensitive portion) corresponding to a refrigerant temperature and a high pressure of the CO 2 refrigerant in the refrigeration cycle to open and close the valve, a volume ratio Vs/(Vs−Vo) of a total volume (Vs) of the sealed space when the valve is fully closed and a total volume (Vo) of the sealed space when the valve is fully open is greater than 1.9 or 2.4. To improve this volume ratio, a cavity 31 d communicating with the sealed space is formed inside a displacement transmission member 31 coupled with the resilient member, or a recess portion 35 a is formed in a cover member 35 a , or a member communicating with the sealed space is connected.

1 . A pressure controlling valve for use in a refrigeration cycle using a CO 2  refrigerant, for generating pressure corresponding to a refrigerant temperature by transferring heat of the refrigerant to a CO 2  gas sealed in a sealed space (A), and causing deformation of a resilient member by a pressure difference between a gas pressure in said sealed space and a high pressure of said refrigerant in said refrigeration cycle to open and close said valve, wherein a volume ratio Vs/(Vs−Vo) of a total volume (Vs) of said sealed space when said valve is fully closed and a total volume (Vo) of said sealed space when said valve is fully open satisfies the following relation:  
         Vs /( Vs−Vo )≧1.9.  
   
   
       2 . A pressure controlling valve as defined in  claim 1 , wherein said volume ratio Vs/(Vs−Vo) is greater than a value of said volume ratio determined from  FIG. 11  with respect to a CO 2  gas density in said sealed space when said valve is fully closed.  
   
   
       3 . A pressure controlling valve as defined in  claim 1 , wherein a control pressure of said pressure controlling valve is not greater than 14 MPa at a refrigerant temperature of 60° C.  
   
   
       4 . A pressure controlling valve as defined in  claim 1 , wherein a control pressure of said pressure controlling valve is at least 9.5 MPa at a refrigerant temperature of 40° C.  
   
   
       5 . A pressure controlling valve as defined in  claim 1 , wherein a space (A 1 ) communicating with said sealed space is formed inside a displacement transmission member hermetically coupled with said resilient member.  
   
   
       6 . A pressure controlling valve as defined in  claim 5 , wherein opening/closing of said valve is made by said displacement transmission member coupled with said resilient member.  
   
   
       7 . A pressure controlling valve as defined in  claim 1 , wherein a recess portion is formed in a cover member on the side opposing said resilient member relative to said sealed space, or a member having a space communicating with said sealed space is connected to said cover member.  
   
   
       8 . A pressure controlling valve as defined in  claim 1 , wherein said resilient member is a diaphragm or bellows.  
   
   
       9 . A pressure controlling valve for use in a refrigeration cycle using a CO 2  refrigerant, for generating a pressure corresponding to a refrigerant temperature by transferring heat of the refrigerant to a CO 2  gas sealed in a sealed space (A), and causing deformation of a resilient member by a pressure difference between a gas pressure in said sealed space and a high pressure of said refrigerant in said refrigeration cycle to open and close said valve, wherein a volume ratio Vs/(Vs−Vo) of a total volume (Vs) of said sealed space when said valve is fully closed and a total volume (Vo) of said sealed space when said valve is fully open satisfies the following relation:  
         Vs /( Vs−Vo )≧2.4.  
   
   
       10 . A pressure controlling valve as defined in  claim 9 , wherein said volume ratio Vs/(Vs−Vo) is greater than a value of said volume ratio determined from  FIG. 12  with respect to a CO 2  gas density in said sealed space when said valve is fully closed.  
   
   
       11 . A pressure controlling valve as defined in  claim 9 , wherein a control pressure of said pressure controlling valve is not greater than 14 MPa at a refrigerant temperature of 60° C.  
   
   
       12 . A pressure controlling valve as defined in  claim 9 , wherein a control pressure of said pressure controlling valve is at least 9.5 MPa at a refrigerant temperature of 40° C.  
   
   
       13 . A pressure controlling valve as defined in  claim 9 , wherein a space (A 1 ) communicating with said sealed space is formed inside a displacement transmission member hermetically coupled with said resilient member.  
   
   
       14 . A pressure controlling valve as defined in  claim 9 , wherein opening/closing of said valve is made by said displacement transmission member coupled with said resilient member.  
   
   
       15 . A pressure controlling valve as defined in  claim 9 , wherein a recess portion is formed in a cover member on the side opposing said resilient member relative to said sealed space, or a member having a space communicating with said sealed space is connected to said cover member.  
   
   
       16 . A pressure controlling valve as defined in  claim 9 , wherein said resilient member is a diaphragm or bellows.