Patent ID: 8371336

Claim:
An accumulator comprising: an accumulator housing provided with an oil port connected to a pressure piping; a bellows and a bellows cap arranged in an internal space of said housing and comparting said internal space into a gas chamber charging high pressure gas and a liquid chamber communicating with a port hole of said oil port; and a seal closing said liquid chamber at a time of zero-down so as to seal a part of liquid in said liquid chamber, the seal being provided in an inner side of said oil port, wherein a movable plate supported by a spring means is provided at the bellows cap side of said oil port, said movable plate is supported by said spring means so as to stay away from said seal at a time of a stationary operation, said movable plate is pushed by said bellows cap so as to come into contact with said seal while elastically deforming said spring means at a time of the zero-down, and said bellows cap moves to a position at which liquid pressure is balanced with gas pressure while said movable plate keeps in contact with said seal, when the liquid sealed in said liquid chamber and the charged gas thermally expand at a time of the zero-down.