Electric pressure pick-off

• US 4,726,233 A
• Filed: 08/18/1986
• Issued: 02/23/1988
• Est. Priority Date: 12/24/1984
• Status: Expired due to Fees

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Gerhard, Hettich, Eckardt, Dieter
• Primary Examiner(s): WOODIEL, DONALD
• Application Number:
  US06/921,049
• Time in Patent Office: 554 Days
• Field of Search: 73/706, 73/723, 73/724, 73/725, 73/726, 73/727, 73/728, 73/753, 73/754, 73/49.3, 338/4, 338/42
• US Class Current: 73/727
• CPC Class Codes: G01L 19/00 Details of, or accessories for, apparatus for measuring steady or quasi-steady pressure of a fluent medium insofar as such details or accessories are not special to particular types of pressure gauges
• CPC Class Codes: G01L 19/0084 to the outside of the housing other details about the housing see G01L19/14
• CPC Class Codes: G01M 3/045 with electrical detection means

Abstract

A pressure pick-off for generating electrical signals comprises a reference pressure chamber which is oxygen-free, at least one pressure dependent deformable membrane closing the reference pressure chamber from a medium under pressure and supporting at least one electric sensor element, and a conductor located in the reference pressure chamber and connectable with a measuring current circuit, the conductor being formed so that during a leakage in the reference pressure chamber it is oxidized by penetrated oxygen so that it is electrically interrupted.

Claims

1. A pressure pick-off for generating electrical signals, comprising means forming a reference pressure chamber which is oxygen-free;

at least one pressure dependent deformable membrane closing said reference pressure chamber from a medium under pressure and supporting at least one electric sensor element; and

a conductor located in said reference pressure chamber and connectable with a measuring current circuit, said conductor being formed so that during a leakage in said reference pressure chamber it is oxidized by penetrated oxygen so that it is electrically interrupted.

2. A pressure pick-of as defined in claim 1, wherein said reference pressure chamber forming means is formed so that said reference pressure chamber is under vacuum.

3. A pressure pick-off as defined in claim 1;

and further comprising a substrate arranged in said pressure reference chamber, said conductor being supported on said substrate.

4. A pressure pick-off as defined in claim 3;

and further comprising a plurality of such electric sensor elements mounted on said substrate in a predetermined area so as to form in said area said pressure dependent deformable membrane.

5. A pressure pick-off as defined in claim 1, wherein said reference pressure chamber has an electrically conductive area;

and further comprising means forming an electrically insulated throughput, said conductor being connected with said electrically conductive area of said reference pressure chamber and with said electrically insulated throughput.

6. A pressure pick-off as defined in claim 5, wherein said electrically conductive area of said reference pressure chamber is formed as an annular conductor of a printed circuit board;

and further comprising a capsule which is pressure-tight mounted on said printed circuit board so as to close said reference pressure chamber, so that said capsule and said deformable membrane together form said reference pressure chamber forming means.

7. A pressure pick-off as defined in claim 1, wherein said conductor is heatable by an electric current and oxidizable when heated by the penetrated oxygen.

8. A pressure pick-off as defined in claim 1, wherein said conductor is composed of nickel.