Pressure responsive switch for gas burner air supply - with height adjustable magnet acting on membrane to block supply in absence of air

摘要

The adjustable pressure differential operated contact with adjustable differential pressure is used for the air supply to a gas burner. It, has a membrane (3) subjected to the differential pressure resulting from the air flow and controlling a safety device (9) for blocking the gas admission. A metal cylinder (10) enclosing a small bar magnet (13) is positioned vertically so as to project into the high pressure chamber (2) at one side of the membrane, with the axis of the magnet aligned with the centre of a metal armature (15) carried by the membrane. The switch is used as part of a safety device for blocking the admission of gas in the absence of an air supply sufficient for combustion esp. in a balanced flue gas central heating boiler.