公开(公告)号：SG43764A1

公开(公告)日：1997-11-14

申请号：SG1996000673

申请日：1993-08-30

Applicant: ROSEMOUNT INC

Inventor： LUTZ MARK A ,  KREUGER WILLIAM B

IPC: G01L7/08 ,  G01L9/00 ,  G01L9/06 ,  G01L9/12 ,  G01L19/06

Abstract: A low range pressure sensor includes a base plate of brittle material, and a diaphragm plate mounted on the base plate and sealed around a periphery to the base plate. Pressures are introduced to cause the diaphragm to deflect toward the base plate, and the deflection of the diaphragm is sensed through strain gauges to provide an indication of the pressure. The diaphragm is provided with a plurality of individual support posts on a side facing the base plate, so that when the diaphragm is deflected toward the base plate under high overpressures the support posts will support the diaphragm against movement to avoid failure or breakage of the diaphragm. The number of support posts can be varied as desired. In a preferred form of the invention, the base plate is provided with a very thin layer of silicon dioxide, which is a good electrical insulator and which also serves to help accommodate slight movement of the support posts as they touch the surface of the base plate to reduce stress buildup in the diaphragm as the overpressure increases.