MEASURING CELL AND A METHOD OF USE THEREFOR

• US 20110100130A1
• Filed: 08/18/2010
• Published: 05/05/2011
• Est. Priority Date: 11/02/2009
• Status: Active Grant

• Current Assignee: VEGA Grieshaber KG (Grieshaber Verwaltungsgesellschaft mbH)
• Original Assignee: VEGA Grieshaber KG (Grieshaber Verwaltungsgesellschaft mbH)
• Inventors: Gruhler, Holger
• Granted Patent: US 8,468,894 B2
• Time in Patent Office: Days
• US Class Current: 73/708
• CPC Class Codes: G01L 1/142 using capacitors
• 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 9/0075 using a ceramic diaphragm, e.g. alumina, fused quartz, glass

Abstract

The present invention is a measuring cell with a base body, a measurement membrane which is arranged on the base body, and a measurement device, where a clearance between the measurement membrane and the base body is filled with a fluid which presents an increased heat conductivity (κ) compared to air.

Claims

1. A measuring cell, said measuring cell comprising:

(a) a base body;

(b) a measurement membrane, wherein said measurement membrane is arranged on said base body;

(c) a clearance, and wherein said clearance is;

(i) located between said measurement membrane and said base body; and

(ii) is filled with a fluid which presents an increased heat capacitance (κ

) compared to air; and

(d) a measurement device.

2. A measuring cell according to claim 1, wherein said measurement device comprises:

(a) a first measuring element, wherein said first measuring element is arranged on said measurement membrane; and

(b) a second measuring element, wherein said second measuring element is arranged on said base body.

3. A measuring cell according to claim 2, wherein said first measuring element and said second measurement element are each measuring electrodes.

4. A measuring cell according to claim 2, wherein said measuring electrodes are designed as flat metallizations of identical size, and form a measuring capacitance (C_M).

5. A measuring cell according to claim 1, wherein a set of one or more reference electrodes, having an annular shape, are provided for the formation of a reference capacitance (C_R).

6. A measuring cell according to claim 1, wherein said fluid is a gas.

7. A measuring cell according to claim 6, wherein said gas is a rare gas.

8. A measuring cell according to claim 7, wherein said rare gas is selected from the group comprising:

(a) helium; and

(b) hydrogen.

9. A measuring cell according to claim 1, wherein said fluid is a liquid.

10. A measuring cell according to claim 9, wherein said fluid is selected from the group comprising:

(a) glycerol; and

(b) water.

11. A measuring cell according to claims claim 1, wherein said measuring cell further comprises a pressure compensation device.

12. A measuring cell according to claim 11, wherein said pressure compensation device is connected by a duct to said clearance.

13. A measuring cell according to claim 11, wherein said pressure compensation device is designed as a pressure compensation membrane which is connected by means of a connection layer to said base body.

14. A measuring cell according to claim 12, wherein a second clearance is formed between said pressure compensation membrane and said base body.

15. A measuring cell according to claim 11, wherein said pressure compensation device is an expansion vessel, and wherein said expansion vessel presents a variable volume.

16. A measuring cell according to claim 11, wherein said pressure compensation device further comprises:

(a) a pressure compensation container; and

(b) a spring loaded piston.

17. A measuring cell according to claim 2, wherein an intermediate membrane is provided between said measurement membrane and said base body, and wherein:

(a) said first measuring element is provided on said measurement membrane; and

(b) said second measuring element is arranged on said intermediate membrane.

18. A measuring cell, said measuring cell comprising:

(a) a base body;

(b) a measurement membrane, wherein said measurement membrane is arranged on said base body;

(c) a clearance, and wherein said clearance is;

(i) located between said measurement membrane and said base body; and

(ii) is filled with a fluid which presents an increased heat capacitance (κ

) compared to air;

(d) a measurement device, wherein said measurement device further comprises;

(i) a first measuring element, wherein said first measuring element is arranged on said measurement membrane; and

(ii) a second measuring element, wherein said second measuring element is arranged on said base body; and

(e) a pressure compensation device.

19. A measuring cell according to claim 18, wherein said pressure compensation device is designed as a pressure compensation membrane which is connected by means of a connection layer to said base body.

20. A method for measuring a pressure state, said method comprising the steps of:

(a) introducing a pressure change to a measurement cell wherein said measurement cell comprises;

(i) a base body;

(ii) a measurement membrane, wherein said measurement membrane is arranged on said base body;

(iii) a clearance, and wherein said clearance is;

(1) located between said measurement membrane and said base body; and

(2) is filled with a fluid which presents an increased heat capacitance (κ

) compared to air;

(iv) a measurement device, wherein said measurement device further comprises;

(1) a first measuring element, wherein said first measuring element is arranged on said measurement membrane; and

(2) a second measuring element, wherein said second measuring element is arranged on said base body; and

(v) a pressure compensation device;

(b) detecting said pressure change imposed on said measurement membrane to form a measuring capacitance; and

(c) measuring, via said measuring device, a magnitude of said pressure change.