Flow sensor

• US 7,013,738 B2
• Filed: 12/22/2003
• Issued: 03/21/2006
• Est. Priority Date: 12/24/2002
• 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, Andersen, Per Ellemose, Pedersen, Nicholas
• Primary Examiner(s): Lefkowitz, Edward
• Assistant Examiner(s): THOMPSON, JEWEL VERGIE
• Application Number:
  US10/745,154
• Publication Number:
  US 20040134288A1
• Time in Patent Office: 820 Days
• Field of Search: 738/612.2, 738/612.1, 738/612.4
• US Class Current: 73/861
• CPC Class Codes: G01F 1/3218 bluff body design
• CPC Class Codes: G01F 1/3266 by sensing mechanical vibrations

Abstract

A flow sensor is provided with an obstruction (8) projecting into a flow and at least one measuring probe (10) for measuring a vortex produced by the obstruction (8). The measuring probe (10) includes at least one membrane (12) and a measuring element arranged directly on the membrane (12), for detecting the membrane deflection.

Claims

1. A flow sensor, comprising:

an obstruction projecting into a flow; and

a measuring probe for measuring a vortex produced by the obstruction, said measuring probe comprising at least one membrane arranged directly in the flow and a measuring element arranged directly on the membrane for detecting the membrane deflection.

2. A flow sensor according to claim 1, further comprising a pipe section, wherein said obstruction and said measuring probe are arranged in said pipe conduit section.

3. A flow sensor according to claim 2, wherein said pipe conduit section has a diameter D which is larger than 10 mm.

4. A flow sensor according to claim 2, wherein the obstruction is designed as one piece with the pipe conduit section.

5. A flow sensor according to claim 1, wherein the membrane may be impinged on one side with a pressure, for determining an absolute pressure value.

6. A flow sensor according to claim 1, wherein said at least one membrane consists of a single membrane impinged on both sides in each case with a pressure, for determining a differential pressure.

7. A flow sensor according to claim 1, further comprising a membrane mounting wherein said membrane is fixed into said membrane mounting in a pressure-tight manner and an electrically insulating layer is deposited directly onto said membrane and onto the measuring element arranged on said membrane, said layer being covered by an at least fluid-tight amorphous metal layer.

8. A flow sensor according to claim 2, further comprising a housing wherein said measuring probe is arranged in said housing and said housing is inserted into an opening in said pipe conduit section.

9. A flow sensor according to claim 1, wherein said measuring probe is integrated into said obstruction.

10. A flow sensor according to claim 1, wherein said measuring probe is ranged behind the obstruction with respect to a flow direction.

11. A flow sensor according to claim 10, further comprising a pipe section, wherein said obstruction and said measuring probe are arranged in said pipe conduit section and wherein in the flow direction a front edge of said obstruction is spaced a distance from a middle of said measuring probe by an amount X, and the pipe conduit section has a diameter D, wherein the ratio X/D lies between 1 and 2.

12. A flow sensor according to claim 10, wherein in the flow direction a front edge of said obstruction is spaced a distanced from a middle of the measuring probe by an amount X and said obstruction transverse to the flow direction has a width d wherein the ratio X/d lies between 2.5 and 10.

13. A flow sensor according to claim 10, wherein the obstruction in the flow direction has a length L and transverse to the flow direction a width d, wherein the ratio L/d lies between 1 and 2.

14. A flow sensor according to claim 10, wherein the obstruction in the flow direction has a length L and the pipe conduit section in which said obstruction is arranged has a diameter D, wherein the ratio L/D lies between 0.4 and 10.

15. A flow sensor according to claim 10, further comprising a pipe section, wherein said obstruction and said measuring probe are arranged in said pipe conduit section and wherein said obstruction transverse to the flow direction has a width d and said pipe conduit section has a diameter D, wherein the ratio d/D lies between 0.2 and 0.4.

16. A flow sensor according to claim 10, further comprising a pipe section, wherein said obstruction and said measuring probe are arranged in said pipe conduit section and wherein the obstruction in the flow direction is situated at least by a distance L₁ behind a bend of the pipe conduit section in which said obstruction is arranged, wherein L₁=4*D and D is the diameter of the pipe conduit section.

17. A flow sensor comprising:

a conduit;

an obstruction projecting into said conduit, said obstruction generating a vortex in a flow carried by said conduit;

a measuring probe arranged in said conduit and measuring the vortex, said measuring probe including a membrane arranged in the conduit extending into the flow carried by the conduit and including a measuring element arranged directly on said membrane for detecting a deflection of said membrane.

18. A sensor in accordance with claim 17, wherein:

said measuring probe includes only a single membrane arranged in said conduit with flow passing along of two opposite sides of said membrane.

19. A sensor in accordance with claim 17, wherein:

said membrane includes an electrically insulating layer and an amorphous metal layer on said insulating layer.

20. A sensor in accordance with claim 17, wherein:

said obstruction is arranged to generate a plurality of vortexes;

said membrane is arranged in said conduit with said plurality of vortexes passing against opposite sides of said membrane and said membrane is arranged to be deflected by the passing of the vortexes.

21. A flow sensor comprising:

a conduit with fluid flowing through having a direction of flow;

an obstruction projecting into said conduit for fluid to flow thereby, said obstruction generating vortexes downstream with respect to said direction of flow of the fluid flowing through said conduit;

a measuring probe arranged in said conduit and measuring the vortexes, said measuring probe including a single membrane having a first side and an opposite second side ranged directly in the fluid flowing through said conduit, said single membrane being arranged downstream of said obstruction first fluid to flow by said first side and by said opposite second side with said first side and opposite second side being arranged to be deflected by the passing of the vortexes and said measuring probe including a measuring element arranged directly on said membrane for detecting a deflection of said single membrane.