Three-piece pressure sensor with high pressure stainless steel sensor

Abstract

An improved pressure sensor assembly includes a low-cost pressure port comprising a casing formed of cold rolled steel, a small stainless steel insert and an O-ring. The casing has a threaded slug at one end for attaching the sensor assembly to the wall of a pressure vessel and an annular cup at the other end. The annular cup has a hex-shaped periphery to facilitate installation and removal of the sensor assembly, and defines a cylindrical interior cavity including an annular recess in which the O-ring is disposed. The stainless steel insert has a base portion disposed within the cylindrical cavity atop the annular recess so as to compress the O-ring between the insert and casing, and a neck portion that extends out of the cavity to form a pedestal to which the stainless steel pressure sensor element is welded. The insert is retained relative to the casing by a staking operation in which a portion of the casing is deformed against the neck of the insert. The casing and insert have central axial openings which align when so assembled, placing the sensor element in communication with the interior of the pressure vessel. A connector assembly covering the sensor element environmentally seals the sensor element and provides access to its electrical pressure signal output. Compared to previously known sensor assemblies, the stainless steel content and required machining are significantly reduced, contributing to an overall cost reduction of the sensor assembly.