Abstract: 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.

Abstract: The high pressure of a gas transport network must be reduced before the gas is admitted to a distribution network to which consumers, e.g. household appliances are connected.This reduction is carried out by a gas pressure control installation. If this installation fails, conduit failure, appliance failure, explosion and fire may occur.A known safety device has a closing spring, which closes a valve if the gas pressure unacceptably rises which causes release of the spring by the gas pressure. The movement releasing the spring is influenced by friction which may have an uncertain value. The invention eliminates friction in that the reduced gas pressure acts on the valve via spring loaded membranes, namely a measuring membrane and an actuating membrane.

Abstract: A fluid actuated switching system is disclosed which comprises a fluid actuated poppet mounted in a fluid passageway for movement from a first position in the absence of fluid flow to a second position in response to a predetermined fluid flow. An elongated permanent magnet element is mounted on the poppet for movement along the axis of movement of the poppet. A second magnet element is positioned exteriorly of the fluid passageway adjacent the first magnet element. The two elongated magnet elements are polarized so that like poles are adjacent to one another and repel the two elements when the flow actuated poppet is in the first position and attract one another when the flow actuated poppet is in the second position, thereby moving the second magnet element with a snap action from one position to the other. The second magnet element actuates an electrical or pneumatic switch.

Abstract: A pressure limiting switch is provided for limiting the upper and lower limit values of the air pressure in a circuit feeding pneumatic controls. The switch has a switching arm which is pivotable at one end around a fixed axis in the switch body and adapted to actuate with its other end a microswitch closing a valve in the circuit if necessary. The air pressure is sensed by a movable element which engages the switching arm between the pivot axis and the microswitch. The switching arm is spring biased for compensating the microswitch spring. The air pressure range is adjustable through adjusting discs serving as abutments for movement of the switching arm.