US 4,389,895 AGranted

Capacitance pressure sensor

AssigneeRosemount Inc.

InventorStanley E. Rud, Jr.

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Abstract

A capacitive pressure sensor has a diaphragm means a portion of which is conductive which forms a first capacitor electrode. The sensor also has a reference disc means a portion of which is conductive which forms a second capacitive electrode. The diaphragm means and the reference disc means are supported in a spaced, over-lying relationship to each other by a peripheral spacer means. Responsive to pressure, the diaphragm means deflects relative to the reference disc means thus changing the capacitive spacing of the diaphragm means and the reference disc means. The diaphragm means, reference disc means and spacer means are formed from substantially the same material. The spacer means is disposed between the diaphragm means and the reference disc means adjacent their outer edges and the diaphragm means, reference disc means and spacer means are then fused together.

Claims19

Dependent claims

Apparatus for measuring pressure comprising:

diaphragm means for deflection under pressure having a first side for application of first pressure thereto, and a second side for application of a second pressure, wherein at least a portion of the diaphragm means is conductive thus forming a first capacitor electrode;
reference disc means having a passageway therethrough for communicating the first pressure to one side of the diaphragm means and having a first disc side and a second disc side, wherein at least a portion of the reference disc means is conductive thus forming a reference capacitor electrode in electrical communication with the first capacitor electrode, and
spacer means for supporting the diaphragm means adjacent its edges in a spaced relationship from the reference disc means,
characterized in that the spacer means is formed from substantially the same material as the diaphragm means and the reference disc means and is disposed therebetween, and wherein the diaphragm means, the reference disc means and the spacer means are then fused together.

1 more element

Dependencies are inferred from the claim text.