Patent ID: 6953325

Claim:
A safety device to limit the pressure in a compressor housing, said compressor housing comprising a discharge pressure zone in which a high pressure is generated and an intake pressure zone in which a suction pressure is generated, said compressor housing further comprising: a piston-drive chamber being part of a piston-drive pressure zone, a first pressure differential existing between the discharge pressure zone and the piston-drive pressure zone and a second pressure differential existing between the piston-drive pressure zone and the intake pressure zone; a connector channel from the discharge pressure zone to the piston-drive pressure zone; wherein: said safety device comprises a valve device arranged in the connector channel; said valve device, in response to said high pressure exceeding a given maximally allowable discharge pressure, allows an increased flow of a pressure medium from the discharge pressure zone to the piston-drive pressure zone; said valve device comprises a movable valve body for closing and opening the valve device, wherein said movable valve body is pushed in an opening direction of the valve device by said high pressure acting against at least a biasing force of a spring; and the valve device comprises a spring compartment adjoining said movable valve body and containing said spring, the movable valve body has a surface area inside the spring compartment, the spring compartment shares an ambient atmospheric pressure, and said ambient atmospheric pressure acts against said surface area.