Differential pressure switch having an isolated hall effect sensor

Abstract

A differential pressure switch comprising an enclosure including a peripheral wall and a solid one-piece non-perforate partition wall that is integrally attached to the peripheral wall around the entire perimeter of the partition wall. The enclosure includes a sensor chamber located on a first side of the partition wall and a fluid cavity located on a second side of the partition wall. The partition wall and the integrally attached peripheral wall seal the sensor chamber in fluid-tight leak-proof isolation from the fluid cavity. A flexible diaphragm is located within the fluid cavity and forms a low-pressure fluid chamber on one side and a high-pressure fluid chamber on a second side of the diaphragm. A magnet is located in the fluid cavity and is coupled to the diaphragm such that the magnet changes position in response to movement of the diaphragm. A Hall effect sensor is located in the sensor chamber. The sensor is adapted to sense the magnetic force generated by the magnet and thereby detect the distance between the magnet and the sensor. The sensor indicates when the magnet is located a predetermined distance from the sensor such that a predetermined differential in pressure exists between the pressure of the fluid in the low-pressure fluid chamber and the pressure of the fluid in the high-pressure fluid chamber.