A PNEUMATIC SWITCHING DEVICE, E.G. FOR SAFEGUARDING AGAINST OVERPRESSURE

摘要

Pneumatic switching devices do not constitute a danger in explosive surroundings contrary to electrical switching devices with which sparking may occur. Known pneumatic devices have the disadvantage of a long actuation path, whereby they can arrive at a so-called "cutting" position. Moreover, they are not suitable for actuation by the very sensitive pressure pick ups constituted by membrane pistons. Also the known pneumatic switching devices have large dimensions. The invention removes said disadvantages in that the switching device has a piston provided in a housing, a switching chamber and a pressure chamber being formed between the housing bore wall and a narrowed piston portion.