Malfunction detection device of a bellows type accumulator for pressurized fluid

A malfunction detection device of a bellows type accumulator for pressurized fluid comprising:

• the bellows type accumulator including a shell which forms a pressure space, a bellows located in the pressure space and whose one end is fluidtightly fixed to one end wall of the shell and whose the other end is fluidtightly fixed to a movable plate, a gas chamber which is formed inside of the bellows and in which pressurized gas is enclosed, a fluid chamber which is formed outside of the bellows and which communicates to an inlet and outlet port formed on the other end wall of the shell and a seal member which is provided on one of the movable plate or the other end of the shell and which contacts with the other of the movable plate or the other end of the shell for preventing the fluid from flowing from the fluid chamber to the inlet and outlet port,
• a pressure sensor which detects the fluid pressure in the inlet and outlet port and
• malfunction judgment means for judging a malfunction of the bellows type accumulator on the basis of a detection output of the pressure sensor,
• wherein the malfunction judgment means judges that the malfunction of the seal member generates when the difference between a peak pressure value appeared before a predetermined time is past after the starting of the pressure increase from a value below a predetermined value in the inlet and outlet port and a stable fluid pressure appeared after the appearance of the peak pressure value is not within a predetermined range and/or when the peak pressure value does not appear before the progress of the predetermined time.