Pressure cell with temperature sensors and pressure measuring method

• US 20020026835A1
• Filed: 07/31/2001
• Published: 03/07/2002
• Est. Priority Date: 09/07/2000
• Status: Active Grant

• Current Assignee: VEGA Grieshaber KG (Grieshaber Verwaltungsgesellschaft mbH)
• Original Assignee: VEGA Grieshaber KG (Grieshaber Verwaltungsgesellschaft mbH)
• Inventors: Jacob, Joern, Boehler, Ewald
• Granted Patent: US 6,698,294 B2
• Time in Patent Office: Days
• US Class Current: 73/708
• CPC Class Codes: G01L 9/0075 using a ceramic diaphragm, e.g. alumina, fused quartz, glass
• CPC Class Codes: G01L 9/125 with temperature compensating means non electric temperature compensating means G01L19/04

Abstract

A pressure cell contains a base body (1), a membrane (2) that is arranged on the base body (1) and can be deformed by a pressure to be measured, as well as a first and a second temperature sensor. The second temperature sensor is spaced apart from the first temperature sensor in the direction of a temperature gradient. Temperature shocks of the measuring cell can be determined and compensated by monitoring the difference between the temperatures measured by the sensors or changes in the temperatures measured by a sensor.

Claims

1. Pressure cell with a base body (1), a membrane (2) that is arranged on the base body (1) and can be deformed by a pressure to be measured and a first temperature sensor, characterized by a second temperature sensor that is spaced apart from the first temperature sensor in the direction of a temperature gradient.

2. Pressure cell according to claim 1, characterized by the fact that the first temperature sensor is arranged at the membrane.

3. Pressure cell according to claim 1 or 2, characterized by the fact that the first temperature sensor is arranged between the membrane (2) and the base body (1).

4. Pressure cell according to claim 1, characterized by the fact that the distance between the first temperature sensor and an outer surface (11) of the membrane (2) which is subjected to the pressure to be measured lies between 0.1 and 3 mm.

5. Pressure cell according to one of the previous claims, characterized by the fact that the first temperature sensor is embedded in a material layer (4) that connects the base body (1) and the membrane (2).

6. Pressure cell according to claim 5, characterized by the fact that the material layer (4) consists of a seal that seals a chamber (3) formed between the base body (1) and the membrane (2).

7. Pressure cell according to claim 5 or 6, characterized by the fact that the base body (1) and/or the membrane (2) consist(s) of a ceramic material, and by the fact that the material layer (4) consists of glass.

8. Pressure cell according to one of the previous claims, characterized by the fact that the first and/or the second temperature sensor contain(s) a resistance element (5,12) with a temperature-dependent resistance value.

9. Pressure cell according to claim 8, characterized by the fact that the resistance element (5) of the first temperature sensor essentially extends over the entire circumference of the material layer (4).

10. Pressure cell according to claim 8 or 9, characterized by the fact that the resistance element (5) extends in a meander-shaped fashion.

11. Pressure cell according to one of the previous claims, characterized by the fact that the second temperature sensor is arranged on the side of the base body which faces away from the membrane.

12. Method for determining the pressure of a fluid with the aid of a pressure cell that contains a base body, a membrane that is arranged on the base body and can be deformed by the pressure of the fluid and a first temperature sensor arranged on the membrane, characterized by the fact that, if the speed of the change in temperature measured by the first temperature sensor or a difference between the temperatures measured by the first temperature sensor and a second temperature sensor that is spaced apart from the first temperature sensor in the direction of a temperature gradient indicates a temperature gradient in the pressure measuring cell, an error in the pressure measuring signal caused by the temperature gradient is calculated, whereafter the pressure measuring value delivered by the pressure cell is corrected by the calculated error.