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:
Mar. 28, 2000
Filed:
Jul. 09, 1998
Douglas W Wilda, Ambler, PA (US);
James V Davidson, Ambler, PA (US);
Max C Glenn, Shorewood, MN (US);
Thomas P Overholt, Chalfont, PA (US);
Raymond F McMullen, Shorewood, MN (US);
Honeywell Inc., Minneapolis, MN (US);
Abstract
The apparatus of the invention includes a sensor header and a sensor cover which are coupled to a prior art diaphragm assembly. The sensor header is provided with two piezoresistive silicon membrane strain gauges. One side of both strain gauges is exposed to fluid at upstream high pressure. The other side of the first strain gauge is exposed to fluid at downstream low pressure and the other side of the second strain gauge is exposed to the atmosphere. The sensor header is provided with a first port which is fluidly coupled to the first membrane strain gauge and extends to the surface of the header at a first location. The sensor header is provided with a second port which is fluidly coupled to the second membrane strain gauge and extends to the surface of the header at a second location. The sensor cover defines two isolated annular spaces around the sensor header, a first annular space around the first location and a second annular space around the second location. The first annular space is fluidly coupled to the low pressure port of a conventional diaphragm assembly and the second annular space is fluidly coupled to the atmosphere. The method of the invention is to provide two piezoresistive membrane strain gauges, expose a first side of each strain gauge to fluid at upstream high pressure, expose the second side of the first strain gauge to fluid at downstream low pressure, and expose the second side of the second strain gauge to atmospheric pressure.