PRESSURE SENSOR

• US 20090211362A1
• Filed: 03/17/2009
• Published: 08/27/2009
• Est. Priority Date: 09/24/2004
• Status: Active Grant

• Current Assignee: Grundfos A/S (Poul Due Jensens Fond)
• Original Assignee: Grundfos A/S (Poul Due Jensens Fond)
• Inventors: KROG, Jens Peter, PEDERSEN, Casper, CHRISTENSEN, Carsten
• Granted Patent: US 7,823,456 B2
• Time in Patent Office: Days
• US Class Current: 73/716
• CPC Class Codes: G01L 9/0054 integral with a semiconducting diaphragm

Abstract

A pressure sensor is provided with a carrier (2), which in an inner region includes a membrane (4) on which at least one first measurement element (R₁₋) for detecting a pressure impingement of the membrane (4) is arranged. Additionally, at least one second measurement element (R₃₋) for detecting a pressure impingement of the membrane (4) is arranged on the membrane. The first measurement element (R₁₋) and the second measurement element (R₃₋) are arranged distanced differently far from the edge of the membrane. The output signals of the first and the second measurement element (R₁₋, R₃₋) are evaluated together in a manner such that the two measurement elements (R₁₋, R₃₋) detect a differential pressure acting on the membrane (4), and thereby compensate the influence of the system pressure acting on both sides of the membrane (4).

Claims

1. A pressure sensor with a carrier (2), which in an inner region comprises a membrane (4) on which at least one first measurement element (R₁₋

) for detecting a pressure impingement of the membrane (4) is arranged, wherein additionally, at least one second measurement element (R₃₋

) for detecting a pressure impingement of the membrane (4) is arranged on the membrane (4), wherein the first measurement element (R₁₋

) is spaced apart a first distance from the edge of the membrane (4) and the second measurement element (R₃₋

) is spaced apart a second distance from the edge of the membrane (4), the first and second distances being different, and the output signals of the first and the second measurement elements (R₁₋

, R₃₋

) are evaluated together in a manner to detect at least one of a differential pressure acting on the membrane (4) compensated by the influence of system pressure acting on both sides of the membrane (4) and a system pressure acting on both sides of the membrane (4).

2. A pressure sensor according to claim 1, wherein the at least one first measurement element (R₁₋

) is arranged in an edge region (R) of the membrane (4), and the at least one second measurement element (R₃₋

) is arranged in a central region (M) or in a neutral region (N) of the membrane (4) situated between the edge region (R) and the central region (M).

3. A pressure sensor according to claim 1, wherein the at least one second measurement element (R₃₋

) is arranged in a central region (M) of the membrane (4), and the at least one first measurement element (R₁₋

) is arranged in an edge region (R) or in a neutral region (N) of the membrane (4) situated between the edge region (R) and the central region (M).

4. A pressure sensor according to claim 1, wherein four first measurement elements (R₁₋

, R₁₊) and four second measurement elements (R₃₋

, R₃₊) are arranged on the membrane (4), which are connected to one another in a bridge circuit.

5. A pressure sensor according to claim 4, wherein each of the four first (R₁₋

, R₁₊) and the four second measurement elements (R₃₋

, R₃₊) are designed or arranged such that two (R₁₋

, R₃₊) of the measurement elements have an output signal with a positive polarity, and two (R₁₊, R₃₋

) of the measurement elements have an output signal with a negative polarity.

6. A pressure sensor according to claim 1, wherein the membrane (4) along a first axis (x) has a different deformation behavior upon pressure impingement than along a second axis (y) extending normal to the first axis (x).

7. A pressure sensor according to claim 1, wherein the at least one first (R₁₋

, R₁₊) and at least one second (R₃₋

, R₃₊) measurement elements are connected to one another in a common bridge circuit.

8. A pressure sensor according to claim 7, wherein the at least one first (R₁₋

, R₁₊) and at least one second (R₃₋

, R₃₊) measurement elements are connected to one another in a Wheatstone bridge circuit, and wherein one of the first (R₁₋

, R₁₊) and one of the second (R₃₋

, R₃₊) measurement elements are arranged connected in series in each branch (A, B, C, D) of the bridge circuit.

9. A pressure sensor according to claim 8, wherein two measurement elements having output signals with a different polarity are connected in series in each branch (A, B, C, D) of the bridge circuit.

10. A pressure sensor according to claim 7, wherein the bridge circuit comprises electrical connections (18) which are used to detect the system pressure as an individual variable.

11. A pressure sensor according to claim 1, wherein the measurement elements (R₁, R₃) are arranged in a region of the membrane (4) in which the greatest deformation occurs during pressure impingement.

12. A pressure sensor according to claim 1, wherein the membrane (4) defines a first axis (x) and a second axis (y), and the membrane (4) in the direction of the second axis (y) has a greater length than in the direction of the first axis (x).

13. A pressure sensor according to claim 12, wherein the ratio of the lengths of the membrane (4) in the direction of the second axis (y) and in the direction of the first axis (x) is between 1.2 and 4, preferably at 2.5.

14. A pressure sensor according to claim 12, wherein the first and second measurement elements (R₁₋

, R₃₋

) seen in the direction of the second axis (y), are arranged in the middle region of the membrane (4).

15. A pressure sensor according claim 12, wherein the membrane (4) is designed in a rectangular manner.

16. A pressure sensor according to claim 1, wherein the membrane (4) is designed differently thick in order to have different deformation behavior in the directions of two axes (x, y).