Patent ID: 8231367

Claim:
A compressor comprising: a compressor main body in which fluid inhaled from an inhale port is compressed, and the compressed fluid is exhausted from an exhaust port; and a pressure retaining device where provided on the exhaust port side of the compressor main body, and retaining pressure on the exhaust port side, wherein the pressure retaining device comprises: a valve body provided on a passage side where communicating with the exhaust port; an urging member where normally urging the valve body into a direction to be closed; and a back-pressure means where an intermediate pressure between the inhale port and the exhaust port of the compressor main body is introduced as back pressure which affects the valve body, and wherein the valve body of the pressure retaining device is opened when a force applied to the valve body by pressure at the exhaust port is greater than another force applied to the valve body by the intermediate pressure of the back-pressure means and force by the urging member.