Pressure transmitter

• US 7,357,032 B2
• Filed: 06/20/2006
• Issued: 04/15/2008
• Est. Priority Date: 05/06/2003
• Status: Expired due to Term

• Current Assignee: VEGA Grieshaber KG (Grieshaber Verwaltungsgesellschaft mbH)
• Original Assignee: VEGA Grieshaber KG (Grieshaber Verwaltungsgesellschaft mbH)
• Inventors: Boehler, Ewald, Jakob, Jorn
• Primary Examiner(s): Allen; Andre J.
• Application Number:
  US11/471,016
• Publication Number:
  US 20070000332A1
• Time in Patent Office: 665 Days
• Field of Search: 737/08, 737/06, 737/56, 257/417
• US Class Current: 73/708
• CPC Class Codes: G01L 19/0046 using isolation membranes G01L13/026 and G01L19/0645 take precedence
• 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. A pressure transmitter, comprising:

a base body having sidewalls that form a recess;

a membrane that seals the recess to form a chamber in cooperation with the base body;

a pressure transmitting medium within the chamber, where the pressure transmitting medium is acted upon by an external pressure on an exterior side of the membrane;

where coefficients of thermal expansion of the 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 chamber is approximately the same as a temperature-induced volume change in the pressure transmitting medium.

2. The pressure transmitter of claim 1, where at least part of the membrane has a corrugated shape.

3. The pressure transmitter of claim 2, where the membrane is partially pot shaped.

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

5. The pressure transmitter of claim 1, where the base body comprises a corrosion-resistant metal.

6. The pressure transmitter of claim 1, where the pressure transmitting medium contains an oil.

7. The pressure transmitter of claim 1, where the base body has a temperature expansion coefficient that is smaller by at least a factor of 10 than that of the pressure transmitting medium.

8. The pressure transmitter of claim 1, where the base body (has a temperature expansion coefficient in the range of 10-100×

10<sup>−

6</sup>/K 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;

a membrane attached to the base body 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 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. The pressure transmitter of claim 9, where the membrane comprises a corrugated surface that forms a surface of the chamber.

11. The pressure transmitter of claim 9, where the pressure transmitting medium comprises a liquid.

12. The pressure transmitter of claim 11, where the liquid comprises an oil.

13. The pressure transmitter of claim 12, wherein the membrane comprises a ceramic.

14. A pressure transmitter, comprising:

a base body having a peripheral surface;

a membrane attached to the base body 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.

15. The pressure transmitter of claim 14, where the membrane comprises a corrugated surface that forms a surface of the chamber.

16. The pressure transmitter of claim 14, where the pressure transmitting medium comprises a liquid.

17. The pressure transmitter of claim 16, where the liquid comprises oil.

18. The pressure transmitter of claim 16, wherein the membrane comprises a ceramic.