THERMAL ANEMOMETER FLOW SENSOR APPARATUS WITH A SEAL WITH CONDUCTIVE INTERCONNECT

• US 20100154532A1
• Filed: 02/19/2009
• Published: 06/24/2010
• Est. Priority Date: 12/23/2008
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Speldrich, Jamie W., Becke, Craig Scott, Ricks, Lamar Floyd
• Granted Patent: US 7,891,238 B2
• Time in Patent Office: Days
• US Class Current: 73/170.120
• CPC Class Codes: G01F 1/6845 Micromachined devices
• CPC Class Codes: G01F 1/692 Thin-film arrangements
• CPC Class Codes: G01F 15/14 Casings, e.g. of special material

Abstract

A flow sensor apparatus and method. A seal with a conductive interconnect is provided that includes a mass flow sense element mounted to a housing containing a thick film and/or thin film bridge structure for sensing media (e.g., mass flow) within a flow tube. The seal effectively isolates wirebond pads and electrical connections from the sensed media. The media, whether liquid or gas, can contain ionics that eventually contaminate the top of the mass flow sense element. The use of the seal with the conductive interconnect thus seals off the electrical connections and prevents exposure to the sensed media.

Claims

1. A flow sensor apparatus, said apparatus comprising:

a flow sense element associated with a flow sensing bridge, wherein said flow sense element and said flow sensing bridge are mounted on a housing and together sense a mass flow within a flow tube; and

a seal with a conductive interconnect, wherein said seal is associated with said flow sensing bridge, such said seal with said conductive interconnect provides a seal that isolates said flow sensing bridge physically from an external environment, thereby eliminating a need for bonding wires with respect to said flow sensor apparatus.

2. The apparatus of claim 1 further comprising:

a discrete signal conditioning circuit that converts a sensed flow into a proportional analog output signal, wherein said discrete signal conditioning circuit is associated with said flow sense element and said flow sensing bridge, and wherein said flow sensing bridge circuit is electrically connected to said signal conditioning circuit.

3. The apparatus of claim 1 further comprising:

a cover in association with said flow tube comprising an inlet port and an outlet port added to one side of said flow sense element mounted on said housing.

4. The apparatus of claim 2 further comprising:

a lead frame comprising a plurality of electrical connectors, wherein said lead frame forms an electrical connection with said flow sense element and said signal conditioning circuit.

5. The apparatus of claim 1 wherein said flow sensing bridge is arranged in a context of a Wheatstone bridge circuit that converts said sensed flow into a corresponding voltage.

6. The apparatus of claim 2 wherein said seal with said conductive interconnect applies a power to said flow sense bridge from said signal conditioning circuit and transfers an output of said flow sense bridge to said signal conditioning circuit.

7. The apparatus of claim 1 wherein said seal with said conductive interconnect allows said flow sense element to be mounted in an inverted down position in order to prevent moisture ingress and dust particle build up within said flow sensor apparatus.

8. The apparatus of claim 1 wherein said flow tube routes a non-turbulent flow across said flow sense element.

9. The apparatus of claim 1 wherein said flow sensing bridge comprises a thick film network.

10. The apparatus of claim 1 wherein said flow sensing bridge comprises a thin film network.

11. A flow sensor apparatus, said apparatus comprising:

a flow sense element associated with a flow sensing bridge, wherein said flow sense element and said flow sensing bridge are mounted on a housing and together sense a mass flow within a flow tube;

a cover in association with said flow tube comprising an inlet port and an outlet port configured with respect to one side of said flow sense element mounted on said housing; and

a seal with a conductive interconnect associated with said flow sensing bridge, wherein said seal with said conductive interconnect provides a seal that isolates said flow sensing bridge physically from an external environment, thereby eliminating a need for bonding wires with respect to said flow sensor apparatus.

12. The apparatus of claim 11 further comprising:

a discrete signal conditioning circuit that converts a sensed flow into a proportional analog output signal, wherein said discrete signal conditioning circuit is associated with said flow sense element and said flow sensing bridge, and wherein said flow sensing bridge circuit is electrically connected to said signal conditioning circuit.

13. The apparatus of claim 11 further comprising:

a lead frame comprising a plurality of electrical connectors, wherein said lead frame forms an electrical connection with said flow sense element and a signal conditioning circuit.

14. A method of configuring a flow sensor apparatus, said method comprising:

associating a flow sense element with a flow sensing bridge;

mounting said flow sense element and said flow sensing bridge on a housing, wherein said flow sense element and said flow sensing bridge together are capable of sensing a mass flow within a flow tube; and

associating a seal with a conductive interconnect with said flow sensing bridge, wherein said seal with said conductive interconnect provides a seal that isolates said flow sensing bridge physically from an external environment, thereby eliminating a need for bonding wires with respect to said flow sensor apparatus.

15. The method of claim 14 further comprising:

providing a discrete signal conditioning circuit that converts a sensed flow into a proportional analog output signal;

associating said discrete signal conditioning circuit with said flow sense element and said flow sensing bridge; and

electrically connecting said flow sensing bridge circuit to said signal conditioning circuit.

16. The method of claim 14 further comprising:

associating a cover with said flow tube; and

configuring said flow tube to include an inlet port and an outlet port located on at least one side of said flow sense element.

17. The method of claim 15 further comprising:

providing a lead frame that includes a plurality of electrical connectors, wherein said lead frame forms an electrical connection with said flow sense element and said signal conditioning circuit.

18. The method of claim 14 further comprising arranging said flow sensing bridge in a context of a Wheatstone bridge circuit that converts said sensed flow into a corresponding voltage.

19. The method of claim 15 further comprising configuring said seal with said conductive interconnect to apply a power to said flow sense bridge from said signal conditioning circuit and transfers an output of said flow sense bridge to said signal conditioning circuit.

20. The method of claim 14 further comprising configuring said seal with said conductive interconnect to allow said flow sense element to be mounted in an inverted down position in order to prevent moisture ingress and dust particle build up within said flow sensor apparatus.