Pressure transmitter

• US 7,062,974 B2
• Filed: 06/28/2001
• Issued: 06/20/2006
• Est. Priority Date: 06/30/2000
• Status: Expired due to Term

• Current Assignee: VEGA Grieshaber KG (Grieshaber Verwaltungsgesellschaft mbH)
• Original Assignee: VEGA Grieshaber KG (Grieshaber Verwaltungsgesellschaft mbH)
• Inventors: Boehler, Ewald, Jacob, Jorn
• Primary Examiner(s): Lefkowitz, Edward
• Assistant Examiner(s): ALLEN, ANDRE J
• Application Number:
  US10/312,975
• Publication Number:
  US 20040020300A1
• Time in Patent Office: 1,818 Days
• Field of Search: 737/08, 737/06, 737/56, 257/417
• US Class Current: 73/708
• CPC Class Codes: G01L 19/04 Means for compensating for effects of changes of temperature , i.e. other than electric compensation
• CPC Class Codes: G01L 19/0645 using isolation membranes, specially adapted for protection

Abstract

The invention relates to a pressure transmitter for an overload-proof pressure gauge, comprising a base body, a separating membrane disposed on a pressure-sensitive side of the pressure transmitter and subjectable to a pressure to be measured, a communicating chamber located inside said base body, which receives a pressure transmission medium, said chamber being closed on the pressure-sensitive side by the separating membrane, wherein the coefficient of thermal expansion of the pressure transmission medium is established in such a way that a temperature-induced change in the volume of the communicating chamber equals a temperature-induced change in the volume of the pressure transmission medium.

Claims

1. Pressure transmitter for a pressure gauge, comprising:

a base body,

a separating membrane disposed on a pressure-sensitive side of the pressure transmitter and subjectable externally to a pressure to be measured,

a communicating chamber inside the base body, said chamber accepting a pressure-transmitting medium and being sealed on the pressure-sensitive side by the separating membrane,

characterized in that the coefficients of thermal expansion of the separating membrane and of the base body and the coefficient of thermal expansion of the pressure-transmitting medium are established such that a temperature-induced volume change in the communicating chamber is the same or at least approximately the same as a temperature-induced volume change in the pressure-transmitting medium.

2. The pressure transmitter of claim 1, wherein at least part of the separating membrane has a corrugated shape, the corrugation of the separating membrane decreasing with increasing temperature.

3. The pressure transmitter of claim 2, wherein the separating membrane is in the shape of a pot.

4. The pressure transmitter of claim 2, wherein the separating membrane has a round cross section with a diameter of less than about 40 mm.

5. The pressure transmitter of claim 1, wherein the base body and/or the separating membrane is/are at comprises corrosion-resistant metal.

6. The pressure transmitter of claim 1, wherein the pressure-transmitting medium comprises oil, preferably a hydraulic oil or a silicone oil.

7. The pressure transmitter of claim 1, wherein the base body and/or the separating membrane has/have temperature expansion coefficients that are smaller by a factor of 10 to 1000 than that of the pressure-transmitting medium.

8. The pressure transmitter of claim 1, wherein the base body and/or the separating membrane has/have temperature expansion coefficient in the range of 10−

100×

10<sup>−

6</sup> K<sup>−

6</sup> for a temperature range of 20–

100°

C.

9. A pressure transmitter for use in a pressure transducer, said pressure transmitter comprising:

a base body having a peripheral wall;

a separating membrane attached to the peripheral wall to form a chamber between said base body and said membrane; and

a pressure transmitting medium contained within said chamber;

wherein coefficients of thermal expansion of said separating membrane and said base body, and the coefficient of thermal expansion of said pressure transmitting medium are such that a temperature-induced volume change in said chamber is at least approximately the same as a temperature-induced volume change in said pressure transmitting medium.

10. A pressure transmitter, comprising:

a base body having a peripheral surface;

a membrane attached to the peripheral surface to form a chamber between said base body and said membrane; and

a medium contained within said chamber;

wherein coefficients of thermal expansion of said membrane, said base body, and said medium are such that a temperature-induced volume change in said chamber is at least approximately the same as a temperature-induced volume change in said medium.