Differential pressure monitoring device and method of setting the same

摘要

The switch comprises an electrical which lead extends through a switch body to a point outside the switch body. A mandrel is provided on the switch body, with a recess in the mandrel, and a movable piston mounted in the recess in the mandrel. A sealed capsule is mounted on the piston and mandrel. The capsule contains gas at a predetermined threshold pressure. The sealed capsule comprises a movable diaphragm bottom plate connected to a top plate. A contact is coupled to the movable piston for engagement with the electrical lead when the gas pressure inside the capsule is lower than the pressure on the outside of the diaphragm sufficient to disengage the diaphragm from the mandrel. The contact is disengaged from the electrical lead when the movable diaphragm is fully engaged with the mandrel and the threshold pressure in the capsule equals or exceeds the pressure outside of the capsule. A retainer connects the top plate to the switch body.