Pressure transducer housing with barometric pressure isolation
First Claim
1. A housing structure for a capacitive transducer that measures the pressure of a gas acting on one surface of a flexible, edge-mounted diaphragm by measuring the capacitance of the diaphragm and a conductive surface of an electrode spaced from the diaphragm by a gap g, the housing structure being sealed to a cover to form a first chamber over the diaphragm, comprising,a central structural member oriented transversely to a central axis and supporting the electrode,a first flange extending radially from said central structural member with an outer diameter F, said first flange mounting the diaphragm,a second flange extending radially from said central structural member having an outer diameter A,an annular groove spacing said first and second flanges having a thickness T2 measured in the direction of the central axis, and having a diameter E measured across the bottom of the groove,a cylindrical boss having an outer diameter B that extends is aligned with and extends axially from the central structural member in a direction opposite from the diaphragm,said outer diameter B of said boss being at least equal to said groove diameter E,whereby the capacitive gap g is substantially isolated from stress applied to the housing structure.
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Accused Products
Abstract
A circular membrane diaphragm is edge-mounted on a generally cylindrical housing structure that allows the diaphragm to deform when a differential pressure is applied across it. The housing structure also supports a circular electrode in an internal chamber and in close proximity to the back surface of the diaphragm to form a variable capacitor. The outer side of the membrane is exposed to a second chamber defined by the housing structure and a cover. A tube connects the second chamber to a gas whose pressure is to be measured. The back of the housing structure is exposed to atmospheric pressure and other ambient atmospheric conditions. The housing structure is characterized by double flanges spaced axially by a deep lateral groove. A central cylindrical boss extends axially from the back side of the housing. The outer diameter B of the boss is at least equal to the diameter E of the groove. This housing structure provides the membrane with a high degree of isolation from external pressure fluctuations. A feedthrough assembly to the electrode is centrally located in the housing. For vacuum and absolute pressure measurements, a sealable vacuum conduit and a chemical getter assembly are also mounted in the central portion of the housing.
84 Citations
10 Claims
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1. A housing structure for a capacitive transducer that measures the pressure of a gas acting on one surface of a flexible, edge-mounted diaphragm by measuring the capacitance of the diaphragm and a conductive surface of an electrode spaced from the diaphragm by a gap g, the housing structure being sealed to a cover to form a first chamber over the diaphragm, comprising,
a central structural member oriented transversely to a central axis and supporting the electrode, a first flange extending radially from said central structural member with an outer diameter F, said first flange mounting the diaphragm, a second flange extending radially from said central structural member having an outer diameter A, an annular groove spacing said first and second flanges having a thickness T2 measured in the direction of the central axis, and having a diameter E measured across the bottom of the groove, a cylindrical boss having an outer diameter B that extends is aligned with and extends axially from the central structural member in a direction opposite from the diaphragm, said outer diameter B of said boss being at least equal to said groove diameter E, whereby the capacitive gap g is substantially isolated from stress applied to the housing structure.
Specification