Scroll type compressor and method for compressing gas

Abstract

A scroll type compressor includes a fixed scroll member, a movable scroll member, an inlet, a discharge port, a discharge valve, a first pressure region and a second pressure region. The inlet is formed through the fixed scroll base plate. The discharge port is formed through the movable scroll member. The discharge valve opens and closes the discharge port. The first pressure region and the second pressure region defined at opposite sides of the movable scroll member apply pressure to the movable scroll member. Gas introduced through the inlet is compressed and highly pressurized in accordance with the movable scroll member orbiting with respect to the fixed scroll member. The highly pressurized gas is discharged from a compression region via the discharge port and the discharge valve. The compressor is provided with a communication passage so as to intercommunicate the first pressure region and the second pressure region during a predetermined period of a compression cycle established by the gas. The gas is flowed between both the pressure regions due to a pressure difference between both pressure regions at timing when the thrust force acting on the back surface of the movable scroll member is large.

What is claimed is:  
     
         1 . A scroll type compressor comprising: 
 a fixed scroll member;    a movable scroll member facing to the fixed scroll member;    a compression region defined between the fixed scroll member and the movable scroll member to compress the gas by orbiting the movable scroll member relative to the fixed scroll member;    an inlet to introduce gas into the compression region;    a discharge port for discharging the pressurized gas from the compression region via the discharge port;    a discharge valve opening and closing the discharge port;    a first pressure region applying pressure to the movable scroll member;    a second pressure region applying pressure to the movable scroll member; and    a communication passage intercommunicating said first pressure region and said second pressure region during a predetermined period of a compression cycle established by the gas.    
     
     
         2 . A scroll type compressor according to  claim 1 , 
 wherein the inlet is formed through the fixed scroll member, and    wherein the discharge port is formed through the movable scroll member.    
     
     
         3 . A scroll type compressor according to  claim 1 , wherein a plurality of said communication passages is formed.  
     
     
         4 . A scroll type compressor according to  claim 1 , wherein said predetermined period corresponds to approximately a single orbit of the movable scroll member.  
     
     
         5 . A scroll type compressor according to  claim 1 , 
 wherein the first pressure region is a compression region defined between the scroll members,    wherein said second pressure region is a backside region defined in the vicinity of a back surface of the movable scroll member,    wherein the backside region includes a high pressure region defined downstream to the discharge valve, a low pressure region communicating with the inlet side and an intermediate pressure region defined between the high pressure region and the low pressure region, and    wherein said communication passage intercommunicates the compression region and the intermediate pressure region during said predetermined period of the compression cycle established by the gas.    
     
     
         6 . A scroll type compressor according to  claim 5 , wherein the communication passage continuously intercommunicates the compression region and the intermediate pressure region during said predetermined period.  
     
     
         7 . A scroll type compressor according to  claim 5  further comprising: 
 a seal member disposed between the intermediate pressure region and the low pressure region; and  
 wherein during said predetermined period the communication passage moves between a first position where the compression region and the intermediate pressure region are intercommunicated and a second position where the communication passage is shut by said seal member.  
 
     
     
         8 . A scroll type compressor according to  claim 5  further comprising: 
 a seal member disposed between the intermediate pressure region and the low pressure region; and  
 wherein during said predetermined period said communication passage moves among a first position where the compression region and the intermediate pressure region are intercommunicated, a second position where the communication passage is shut by said seal member and a third position where the compression region and the low pressure region are intercommunicated.  
 
     
     
         9 . A scroll type compressor according to  claim 5  further comprising: 
 a flap valve disposed between the compression region and the intermediate pressure region; and  
 wherein said flap valve opens and closes said communication passage due to a pressure difference between the compression region and the intermediate pressure region during said predetermined period.  
 
     
     
         10 . A method for compressing gas in a scroll type compressor comprising: 
 a fixed scroll member;    a movable scroll member facing to the fixed scroll member;    a compression region defined between the fixed scroll member and the movable scroll member to compress the gas by orbiting the movable scroll member relative to the fixed scroll member;    an inlet to introduce gas into the compression region;    a discharge port for discharging the pressurized gas from the compression region via the discharge port;    a discharge valve opening and closing the discharge port;    a first pressure region applying pressure to the movable scroll member;    a second pressure region applying pressure to the movable scroll member;    wherein the method comprises the steps of:    introducing gas from the inlet;    compressing and highly pressurizing the gas;    intercommunicating the first pressure region and the second pressure region during a predetermined period of a compression cycle established by the gas; and    discharging the pressurized gas from the compression region via the discharge port and the discharge valve.    
     
     
         11 . A method for compressing gas in a scroll type compressor according to  claim 10 , 
 wherein the inlet is formed through the fixed scroll member, and    wherein the discharge port is formed through the movable scroll member.    
     
     
         12 . A method for compressing gas in a scroll type compressor according to  claim 10 , wherein the predetermined period corresponds to approximately a single orbit of the movable scroll member.  
     
     
         13 . A method for compressing gas in a scroll type compressor according to  claim 10 , 
 wherein the first pressure region is a compression region defined between the scroll members,    wherein the second pressure region is a backside region defined in the vicinity of a back surface of the movable scroll member,    wherein the backside region includes a high pressure region defined downstream to the discharge valve, a low pressure region communicating with the inlet side and an intermediate pressure region defined between the high pressure region and the low pressure region,    wherein the method comprises the steps of:    introducing gas from the inlet;    compressing and highly pressurizing the gas;    intercommunicating the compression region and the intermediate pressure region during the predetermined period of the compression cycle established by the gas; and    discharging the highly pressurized gas from the compression region via the discharge port and the discharge valve.    
     
     
         14 . A method for compressing gas in a scroll type compressor according to  claim 13 , wherein the method comprises the step of continuously intercommunicating the compression region and the intermediate pressure region during the predetermined period.  
     
     
         15 . A method for compressing gas in a scroll type compressor according to  claim 13 , 
 wherein a seal member is disposed between the intermediate pressure region and the low pressure region, and    wherein the method further comprises the step of:    shutting communication between the compression region and the intermediate pressure region by the seal member during the predetermined period.    
     
     
         16 . A method for compressing gas in a scroll type compressor according to  claim 13 , 
 wherein a seal member is disposed between the intermediate pressure region and the low pressure region,    wherein the method further comprises the steps of:    shutting communication between the compression region and the intermediate pressure region by the seal member during the predetermined period; and    intercommunicating the compression region and the low pressure region during the predetermined period.    
     
     
         17 . A method for compressing gas in a scroll type compressor according to  claim 13 , 
 wherein a flap valve is disposed between the compression region and the intermediate pressure region,    wherein the method further comprises the step of:    opening and closing the communication passage by the flap valve due to a pressure difference between the compression region and the intermediate pressure region during the predetermined period.