Differential pressure switch including a vertical diaphragm, a reed switch activated by a first magnet and additional magnets for positioning the diaphragm and the first magnet

A differential pressure switch mounted to a source of a medium comprising:

• a housing defining a cavity;
• a diaphragm vertically disposed across the cavity and secured to said housing to divide the cavity into a high pressure chamber and a low pressure chamber;
• said housing further defining a means for admitting fluid pressures into the chambers for moving said diaphragm in response to differential pressure between the chambers;
• said housing further defining a series of ducts running between a lower end of the chambers and the means for admitting fluid pressures into the chambers;
• a first plate attached to one side of said diaphragm;
• a second plate attached to the other side of said diaphragm;
• said first plate and said second plate having an outer diameter which overlaps the ducts;
• a bridge connected to said diaphragm, said bridge having one end projecting into the high pressure chamber and another end projecting into the low pressure chamber to define two gaps, respectively, between the ends of said bridge and said housing, each gap having a width equal to the width of each of the chambers;
• said bridge having a rim circumscribing each end of said bridge, each of said rims defining a slot;
• a first magnet attached to said bridge in the high pressure chamber;
• a second magnet attached to said bridge in the low pressure chamber;
• a third magnet disposed in said housing having a field oriented to oppose the field of said second magnet for positioning said diaphragm and said first magnet within the cavity;
• and
• a reed switch disposed in said housing within a field of said first magnet for maintaining said reed switch in a non-detecting state, said reed switch being transformable to a detecting state by movement of said first magnet when said diaphragm is moved in response to an actuating differential pressure between the chambers.