The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 10, 1983
Filed:
Apr. 17, 1980
Jerome M Paros, Redmond, WA (US);
Paroscientific, Inc., Redmond, WA (US);
Abstract
A digital differential pressure transducer with relatively low sensitivity to common mode line pressure errors. The transducer includes an airtight enclosure having a pair of pressure ports through which pressure is coupled to opposite sides of a pressure-sensing diaphragm or bellows. The force generated by the pressure differential across the diaphragm or bellows is coupled to a stress-sensitive resonator either directly or through a force-transmitting structure. A first bellows extends from the diaphragm or a bellows end cap. The first bellows has an effective area which is substantially smaller than the effective area of the pressure-sensing diaphragm or bellows so that it applies substantially less pressure-induced stress to the resonator than does the pressure-sensing diaphragm or bellows. A second bellows has an effective area and a mounting position chosen to counteract the effect of the first bellows on the pressure-sensing diaphragm or bellows. The common mode line pressure error of the transducer resulting from a mismatch between the forces generated by the first and second bellows is thus proportional to the ratio of the effective area of the first bellows to the effective area of the pressure-sensing diaphragm or bellows. This ratio can be minimized to minimize the common mode line pressure error. The first and second bellows encapsulate or surround either the resonator or a portion of the force-transmitting structure to isolate the resonator from the pressure ports, thereby optimizing the performance of the resonator.