Scroll type compressor and method for compressing gas

摘要

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.