PURPOSE: To hold a pressure in a crank chamber approximately at a set value during running of a compressor.
CONSTITUTION: A case 29 arranged to a head 3 is partitioned into an atmospheric chamber A and a valve chamber B by means of a bellows 33 in which a spring 37 is arranged. The valve chamber B is communicated with a crank chamber through a pressure introduction passage 39 and a communicating passage 38. A valve hole 29c formed in the case 29 such that the valve chamber B is communicated with a suction chamber S is openably closed by a ball valve 36 energized through the force of the spring 37. When a pressure in a crank chamber C is reduced to a value lower than a set value, a valve mechanism is closed to stop gas reduced from the crank chamber C to the suction chamber S. Reversely, when the pressure exceeds the set value, the valve mechanism is opened to reduce gas from the crank chamber C to the suction chamber S.
OTA MASAKI
TAKENAKA KENJI
