Balanced fluid pressure sensor

• US 6,722,204 B2
• Filed: 10/09/2001
• Issued: 04/20/2004
• Est. Priority Date: 04/09/1999
• Status: Expired due to Fees

• Current Assignee: Lucas Industries Limited (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Original Assignee: Lucas Industries Limited (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Inventors: Gegalski, Helmut
• Primary Examiner(s): Lefkowitz, Edward
• Assistant Examiner(s): Dickens, Charlene
• Application Number:
  US09/973,478
• Publication Number:
  US 20020046611A1
• Time in Patent Office: 924 Days
• Field of Search: 737/16, 737/15, 737/00, 737/17, 737/30, 731/16, 731/18, 737/56
• US Class Current: 73/716
• CPC Class Codes: B60T 8/3675 integrated in modulator units
• CPC Class Codes: F15B 11/028 for controlling the actuating force F15B11/024 takes precedence
• CPC Class Codes: F15B 13/0803 Modular units
• CPC Class Codes: F15B 2013/004 Cartridge valves
• CPC Class Codes: F15B 2211/25 Pressure control functions
• CPC Class Codes: F15B 2211/50554 the pressure control means controlling a pressure downstream of the pressure control means, e.g. pressure reducing valve
• CPC Class Codes: F15B 2211/526 electrically or electronically
• CPC Class Codes: F15B 2211/6313 the pressure being a load pressure
• CPC Class Codes: F15B 2211/6346 representing a state of input means, e.g. joystick position
• CPC Class Codes: F15B 2211/6653 Pressure control
• CPC Class Codes: F15B 2211/7052 Single-acting output members
• CPC Class Codes: F15B 2211/857 Monitoring of fluid pressure systems
• CPC Class Codes: G01L 19/0007 Fluidic connecting means
• CPC Class Codes: G01L 19/003 using a detachable interface or adapter between the process medium and the pressure gauge
• CPC Class Codes: G01L 19/0084 to the outside of the housing other details about the housing see G01L19/14
• CPC Class Codes: G01L 19/0645 using isolation membranes, specially adapted for protection
• CPC Class Codes: G01L 19/14 Housings G01L19/0007, G01L19/0084, G01L19/0092, G01L19/04, G01L19/06 take precedence
• CPC Class Codes: G01L 19/142 Multiple part housings
• CPC Class Codes: G01L 19/147 Details about the mounting of the sensor to support or covering means
• CPC Class Codes: G01L 19/148 Details about the circuit board integration, e.g. integrated with the diaphragm surface or encapsulation
• CPC Class Codes: G01L 9/0051 : using variations in ohmic resistance
• CPC Class Codes: G01L 9/0072 : using variations in capacitance

Abstract

An arrangement for measuring a fluid pressure, comprising a pressure sensor portion (10), which is devised for accommodation in a recess (12), which is open at least at one end, wherein the pressure sensor portion (10) in relation to the recess (12) is to be dimensioned in such a way that the pressure sensor portion (10) is surrounded by a gap (14) for receiving fluid, wherein first and second surfaces (16a, 16b, 18a, 18b), which are situated on the pressure sensor portion (10) and in contact with fluid, are so dimensioned and aligned that forces, which are exerted by the fluid pressure on the first surfaces (16a, 16b) and push the pressure sensor portion (10) in the direction of the open end of the recess, are equal to or lower than the forces, which are exerted by the fluid pressure on the second surfaces (18a, 18b) and push the pressure sensor portion (10) away from the open end of the recess (12).

Claims

1. An arrangement for measuring a fluid pressure, comprising

a portion (10) devised for accommodation in a recess (12), which is open at least at one end, wherein the portion (10) being so dimensioned in relation to the recess (12) that the portion (10) is surrounded by an annular recess (14) formed in a surface thereof for receiving fluid, with a fluid inlet disposed in a wall of the recess (12) that is associated with said annular recess (12), the portion (10) including first surfaces (16a, 16b) and second surfaces (18a, 18b), which are situated on the portion (10) and in contact with fluid and are so dimensioned and aligned that forces, which are exerted by the fluid pressure on the first surfaces (16a, 16b) and push the portion (10) in the direction of the open end of the recess (12), are equal to or lower than forces, which are exerted by the fluid pressure on the second surfaces (18a, 18b) and push the portion (10) away from the open end of the recess (12);

and

a pressure sensor (26) carried in the region of said annular recess (14) formed in said portion (10).

2. The arrangement for measuring a fluid pressure according to claim 1, wherein said first and second surfaces (16a, 16b, 18a, 18b), which are situated on said pressure sensor portion (10) and in contact with fluid, are so dimensioned and aligned that said forces, which are exerted by said fluid pressure on said first surfaces (16a, 16b) and push said pressure sensor portion (10) in the direction of the open end of the recess (12), are equal to said forces, which are exerted by said fluid pressure on said second surfaces (18a, 18b) and push said pressure sensor portion (10) away from the open end of the recess (12).

3. The arrangement for measuring a fluid pressure according to claim 2, wherein a first pair (16a and 18a) of said first and second surfaces and a second pair (16b, 18b) of said first and second surfaces are, in relation to a center plane (M), symmetrical to one another.

4. The arrangement for measuring a fluid pressure according to claim 3 wherein said pressure sensor portion (10) is secured in said recess (12) by a retaining means.

5. The arrangement for measuring a fluid pressure according to claim 3 wherein said pressure sensor portion (10) has a shape, which in relation to a center line (L) is rotationally symmetrical.

6. The arrangement for measuring a fluid pressure according to claim 1, wherein the pressure sensor portion (10) in a middle region includes a first collar (20) with a substantially closed lateral surface 20a located between one of said first surfaces (16a) and one of said second surfaces (18a), and wherein said first surface (16a) and said second surface (18a) of said first collar (20) and in relation to a center plane (M) have substantially identical projected areas.

7. The arrangement for measuring a fluid pressure according to claim 6 wherein disposed at axial distances from said first and said second surfaces (16a, 18a) of said first collar (20) are a second and a third collar (22, 24), the external dimensions of which are such that said second and third collars help guide the pressure sensor portion (10) in the recess (12) and include the other of said first and second surfaces (16b, 18b), which face said first collar (20), and in relation to said center plane (M) have substantially identical projected areas.

8. The arrangement for measuring a fluid pressure according to claim 7 wherein said pressure sensor portion and at least portions of said first, second and third collars (20, 22, 24) have a cylindrical shape.

9. The arrangement for measuring a fluid pressure according to claim 7 wherein a seal is disposed between one of said first collar (20) and said second collar (22) and said first collar (20) and said third collar (24).

10. the arrangement for measuring a fluid pressure according to claim 9 wherein ambient atomospheric pressure prevails outside of at least one of said second and third collars (22, 24).

11. The arrangement for measuring a fluid pressure according to claim 9 wherein said seals (30, 32), which are disposed between the first collar (20) and the second collar (22) or between the first collar (20) and the third collar (24), are such that during operation said seals behave like a fluid when they are applied against one of said first surfaces (16b) and one of said second surfaces (18b) of said pressure sensor portion (10).

12. The arrangement for measuring a fluid pressure according to claim 9 wherein said pressure sensor portion (10) is secured in the recess (12) by a retaining means.

13. The arrangement for measuring a fluid pressure according to claim 6 wherein the pressure sensor portion (10) is disposed in said recess (12) in such a way that said first collar (20) faces said fluid inlet disposed in said wall of said recess (12).

14. The arrangement for measuring a fluid pressure according to claim 6 wherein said pressure sensor portion (10) has a shape, which in relation to a center line (L) is rotationally symmetrical.

15. The arrangement for measuring a fluid pressure according to claim 6 wherein said pressure sensor portion (10) includes a pressure sensor (26) in the region of said first collar (20).

16. The arrangement for measuring a fluid pressure according to claim 1 wherein said pressure sensor portion (10) is an elongate body that includes said first and second surfaces (16a, 16b, 18a, 18b) and a longitudinal axis (L) and further wherein the sum of, relative to said longitudinal axis (L), orthogonal projections of said first surfaces (16a, 16b), which are oriented substantially in a first direction and during operation are wetted by a fluid, the pressure of which is to be measured, is substantially equal to or less than the sum of, relative to the longitudinal axis, orthogonal projections of said second surfaces (18a, 18b), which are oriented substantially in a second direction opposed to said first direction and during operation are wetted by said fluid, the pressure of which is to be measured.

17. The arrangement for measuring a fluid pressure according to claim 4 wherein said retaining means is a snap ring (36).

18. The arrangement for measuring a fluid pressure according to claim 12 wherein said retaining means is a snap ring (36).

19. The arrangement for measuring a fluid pressure according to claim 7 wherein a first seal (32) is disposed between said first collar (20) and said second collar (22) and a second seal (30) is disposed between said first collar (20) and said third collar (24).

20. The arrangement for measuring a fluid pressure according to claim 7 wherein said pressure sensor portion and at least portions of said first, second and third collars (20, 22, 24) have a conical shape.