Ultra low pressure drop flow sensor

• US 20070193368A1
• Filed: 02/17/2006
• Published: 08/23/2007
• Est. Priority Date: 02/17/2006
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Speldrich, Jamie
• Granted Patent: US 7,343,823 B2
• Time in Patent Office: Days
• US Class Current: 73/861.52
• CPC Class Codes: G01F 1/46 Pitot tubes
• CPC Class Codes: G01F 1/6845 Micromachined devices
• CPC Class Codes: G01F 1/72 Devices for measuring pulsing fluid flows
• CPC Class Codes: G01F 5/00 Measuring a proportion of the volume flow

Abstract

A fluid velocity sensor includes a sensor die for detecting a fluid property of a fluid flowing through a low resistance flow channel defined by a flow channel wall. One or more tap can be oriented facing into a direction of a flow stream of a fluid flowing through a flow channel defined by a channel wall, wherein the tap(s) leads to the low resistance flow channel, which directs the flow to the sensor die. At least one or more other taps can be located to face perpendicular to the direction of flow, such that the fluid after passing over the sensor die continues on a low resistance path to the other tap(s) facing perpendicular to the direction of flow in order to determine a velocity pressure based on a difference between pressures. The fluid velocity sensor can be arranged in a uni-directional or bidirectional fluid flow configuration.

Claims

1. A fluid velocity sensor apparatus, comprising:

a sensor die for detecting a fluid property of a fluid flowing through a low resistance flow channel defined by a flow channel wall; and

at least one tap facing into a direction of a flow stream of a fluid flowing through a flow channel defined by a flow channel wall, wherein said at least one tap leads to said low resistance flow channel, which directs said flow of fluid to said sensor die, such that said fluid after passing over said sensor die continues on a low resistance path to at least one other tap that faces perpendicular to said direction of flow in order to determine a velocity pressure based on a difference between a pressure identified by said at least one tap and a pressure identified by said at least one other tap.

2. The apparatus of claim 1 wherein:

said at least one tap comprises an upstream tap oriented in an upstream location of said flow channel, wherein said upstream tap faces a direction of said flow of said fluid through said flow channel, wherein said upstream tap senses a stagnation pressure of said fluid; and

said at least one other tap comprises a downstream tap oriented to face perpendicular to said flow of said fluid, wherein said downstream tap senses a static pressure, wherein a difference between said stagnation pressure and said static pressure comprises said velocity pressure.

3. The apparatus of claim 1 wherein said low resistance flow channel controls and laminarizes said flow of said fluid.

4. The apparatus of claim 1 wherein said sensor die comprises a MEMS sensor.

5. The apparatus of claim 1 further comprising at least one flow straightener associated with said flow channel, wherein said at least one flow straightener promotes a bidirectional flow of fluid through said flow channel.

6. The apparatus of claim 5 wherein said at least one flow straightener comprises a shape of a narrow, elongated protrusion that prevents flow eddies that create pressure instability.

7. A fluid velocity sensor apparatus, comprising:

a sensor die for detecting a fluid property of a fluid flowing through a low resistance flow channel defined by a flow channel wall;

at least one tap facing into a direction of a flow stream of a fluid flowing through a flow channel defined by a flow channel wall, wherein said at least one tap leads to said low resistance flow channel, which directs said flow of fluid to said sensor die, such that said fluid after passing over said sensor die continues on a low resistance path to at least one other tap that faces perpendicular to said direction of flow in order to determine a velocity pressure based on a difference between a pressure identified by said at least one tap and a pressure identified by said at least one other tap; and

at least one flow straightener associated with said flow channel, wherein said flow straightener promotes a bidirectional flow of fluid through said flow channel.

8. The apparatus of claim 7 wherein said at least one flow straightener comprises a shape of a narrow, elongated protrusion that prevents flow eddies that create pressure instability.

9. The apparatus of claim 7 wherein;

said at least one tap comprises an upstream tap oriented in an upstream location of said flow channel, wherein said upstream tap faces a direction of said flow of said fluid through said flow channel, wherein said upstream tap senses a stagnation pressure of said fluid; and

said at least one other tap comprises a downstream tap oriented to face perpendicular to said flow of said fluid, wherein said downstream tap senses a static pressure, wherein a difference between said stagnation pressure and said static pressure comprises said velocity pressure.

10. The apparatus of claim 7 wherein said low resistance flow channel controls and laminarizes said flow of said fluid.

11. The apparatus of claim 7 wherein said sensor die comprises a MEMS sensor.

12. A fluid velocity sensor apparatus, comprising:

a sensor die for detecting a fluid property of a fluid flowing through a low resistance flow channel defined by a flow channel wall; and

at least one tap facing into a direction of a flow stream of a fluid flowing through a flow channel defined by a flow channel wall, wherein said at least one tap leads to said low resistance flow channel, which directs said flow of fluid to said sensor die, such that said fluid after passing over said sensor die continues on a low resistance path to at least one other tap that faces opposite said direction of flow in order to determine a velocity of said fluid.

13. The apparatus of claim 12 wherein said low resistance flow channel controls and laminarizes said flow of said fluid.

14. The apparatus of claim 12 wherein said sensor die comprises a MEMS sensor.

15. The apparatus of claim 12 further comprising at least one flow straightener associated with said flow channel, wherein said at least one flow straightener promotes a bidirectional flow of fluid through said flow channel.

16. The apparatus of claim 15 wherein said at least one flow straightener comprises a shape of a narrow, elongated protrusion that prevents flow eddies that create pressure instability.

17. A method of forming a fluid velocity sensor apparatus, comprising:

providing a sensor die for detecting a fluid property of a fluid flowing through a low resistance flow channel defined by a flow channel wall; and

locating at least one tap facing into a direction of a flow stream of a fluid flowing through a flow channel defined by a flow channel wall, wherein said at least one tap leads to said low resistance flow channel, which directs said flow of fluid to said sensor die, such that said fluid after passing over said sensor die continues on a low resistance path to at least one other tap that faces perpendicular to said direction of flow in order to determine a velocity pressure based on a difference between a pressure identified by said at least one tap and a pressure identified by said at least one other tap.

18. The method of claim 17 further comprising:

configuring said at least one tap to comprise an upstream tap oriented in an upstream location of said flow channel, wherein said upstream tap faces a direction of said flow of said fluid through said flow channel, wherein said upstream tap senses a stagnation pressure of said fluid; and

configuring said at least one other tap to comprise a downstream tap oriented to face perpendicular to said flow of said fluid, wherein said downstream tap senses a static pressure, wherein a difference between said stagnation pressure and said static pressure comprises said velocity pressure.

19. The method of claim 17 further comprising configuring said low resistance flow channel to control and laminarize said flow of said fluid.

20. The method of claim 17 wherein said sensor die comprises a MEMS sensor.