Pressure transducer using permanent magnet and opposing variable magnetic field

U.S. Patent Number: 5317948

Abstract: An electromagnetic fluid pressure transducer is provided which uses the opposing magnetic fields of a permanent magnet and an electromagnet to sense a change in a differential force. The differential force is the result of a pressure applied to the unequal surface areas of two pistons attached to opposite poles of the permanent magnet. The differential force displaces the permanent magnet which activates a counter whose output controls the field strength of an electromagnet. The magnetic field of the electromagnet is varied by the counter output to counterbalance the differential force by interacting with the field of the permanent magnet. The field strength of the electromagnet is varied until the magnetic force is sufficient to overcome the differential force and return the permanent magnet to its original position which stops the counter. As a result, the counter output which changes in proportion to change in the ambient pressure acting against the pistons can be used to indicate pressure.

Inventors: Blaha; John G. (Garden Grove, CA)

Assignee: Hughes Aircraft Company (Los Angeles, CA)

Application Number: 07/916,300

Issued: 1994-06-07

Expired: 2006-06-07

Classes: 73/701 ; 250/231.19; 336/30; 73/705; 73/745

Field of search: 73/722,728,701,705,729,745,4R,718 336/30 250/231.19,231.1,222.1

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