IPC분류정보
국가/구분 |
United States(US) Patent
등록
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국제특허분류(IPC7판) |
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출원번호 |
US-0975644
(2004-10-27)
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발명자
/ 주소 |
- Vincze,Craig A.
- Gibson,James
- Parsons,James D.
- Fehlman,Thomas E.
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출원인 / 주소 |
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대리인 / 주소 |
Koppel, Jacobs, Patrick &
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인용정보 |
피인용 횟수 :
7 인용 특허 :
11 |
초록
▼
A mass flow meter employs discrete chip-type temperature sensors to sense a fluid flow rate. The sensor can be a semiconductor chip such as SiC or silicon, or thin film tungsten on an AlN substrate. The sensors can be distributed symmetrically with respect to the conduit through which the fluid flo
A mass flow meter employs discrete chip-type temperature sensors to sense a fluid flow rate. The sensor can be a semiconductor chip such as SiC or silicon, or thin film tungsten on an AlN substrate. The sensors can be distributed symmetrically with respect to the conduit through which the fluid flows, and can be connected in a four-sensor bridge circuit for accurate flow rate monitoring. An output from the mass flow meter can be used to control the fluid flow.
대표청구항
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We claim: 1. A mass flow meter (MFM) structure, comprising: a conduit for conducting a fluid flow, and at least four mutually spaced temperature sensors disposed to sense the temperature of a fluid flowing within said conduit and arranged in upstream and down-stream pairs along said conduit, with t
We claim: 1. A mass flow meter (MFM) structure, comprising: a conduit for conducting a fluid flow, and at least four mutually spaced temperature sensors disposed to sense the temperature of a fluid flowing within said conduit and arranged in upstream and down-stream pairs along said conduit, with the sensors of each pair located the same distance along the conduits length and symmetrically on opposite sides of the conduit from each other, said sensors connected in a 4-sensor bridge circuit to sense the mass flow rate of a fluid flowing through said conduit. 2. The MFM structure of claim 1, wherein said sensors are discrete and are distributed symmetrically with respect to said conduit. 3. The MFM structure of claim 1, said sensors comprising semiconductor chips. 4. The MFM structure of claim 3, said sensors comprising SiC chips. 5. The MFM structure of claim 4, further comprising a SiC oxide interfacing between said SiC chips and said conduit. 6. The MFM structure of claim 3, said sensors comprising silicon chips. 7. The MFM structure of claim 6, further comprising a silicon oxide interfacing between said silicon chips and said conduit. 8. The MFM structure of claim 1, further comprising an electrically insulative film enclosing said sensors, and a circuit on the exterior of said film and extending through the film to contact said sensors. 9. The MFM structure of claim 1, wherein said sensors are mounted to said conduit by respective first layers on said sensors and conduit of a material selected from the group comprising TiW and Ni, and respective second layers on said sensors and conduit of Au, with said sensor and conduit second layers bonded to each other. 10. The MFM structure of claim 9, wherein said sensors comprise semiconductor chips, further comprising an oxide of said semiconductor interfacing between said sensors and said sensor first layers. 11. The MFM structure of claim 1, said sensors comprising thin film tungsten layers on respective AlN substrates. 12. The MFM structure of claim 1, said bridge circuit including extended leads between said upstream and downstream sensors long enough to be substantially non-thermoconductive. 13. The MFM structure of claim 1, wherein said sensors include respective AlN substrates that are mounted to said conduit. 14. The MFM structure of claim 1, further comprising electronic circuitry for actuating said sensors and determining the mass flow rate of a fluid flowing through said conduit from said sensors. 15. The MFM structure of claim 14, wherein said electronic circuitry operates without amplification of the sensor outputs. 16. The MFM structure of claim 14, further comprising a control valve governing the fluid flow through said conduit under the control of said circuitry. 17. The MFM structure of claim 1, wherein said sensors are mounted inside said conduit on protective shields and protected from the enviornment within the conduit by said shields. 18. The MFM structure of claim 1, wherein said sensors are connected directly to each other in said bridge circuit. 19. A mass flow meter (MFM) comprising: a conduit for conducting a fluid flow, a plurality of temperature sensors disposed to sense the temperature of a fluid flowing through said conduit and arranged in upstream and downstream pairs along said conduit, with the sensors of each pair located the same distance along the conduit's length and symmetrically on opposite sides of the conduit from each other, each sensor comprising an AlN substrate bearing a temperature sensing circuit, and electronic circuitry for actuating said sensors and determining from said sensors the mass flow rate of a fluid flowing through said conduit. 20. The MFM of claim 19, said temperature sensing circuits comprising respective thin film tungsten layers on said AlN substrates. 21. The MFM of claim 19, wherein each AlN substrate is mounted to the outer surface of said conduit to conduct heat from said conduit to its respective temperature sensing circuit. 22. The MFM of claim 19, further comprising a control valve governing the fluid flow through said conduit under the control of said circuitry. 23. A fluid mass flow meter (MFM), comprising: a conduit for conducting a fluid flow, a plurality of discrete temperature sensors carried by to said conduit to sense the temperature of a fluid within said conduit and arranged in upstream and downstream pairs along said conduit, with the sensors of each pair located the same distance along the conduit's length and symmetrically on opposite sides of the conduit from each other, and electronic circuitry for actuating said at least one sensor and sensing the mass flow rate of a fluid flowing through said conduit from said sensors. 24. The MFM of claim 23, each said sensor comprising a semiconductor chip. 25. The MFM of claim 24, each said semiconductor chip comprising a SiC chip. 26. The MFM of claim 25, further comprising a SiC oxide interfacing between each SiC chip and said conduit. 27. The MFM of claim 24, each said semiconductor chip comprising a silicon chip. 28. The MFM of claim 27, further comprising a silicon oxide interfacing between each silicon chip and said conduit. 29. The MFM of claim 23, each said sensor comprising a thin film tungsten layer on a respective AlN substrate. 30. The MFM of claim 23, further comprising an electrically insulative film enclosing each said sensor, and a circuit on the other side of said film and extending through the film to contact each sensor. 31. The MFM of claim 23, wherein each said sensor is mounted to said conduit by respective layers on said sensor and conduit of a material selected from the group comprising TiW and Ni, and respective second layers on said sensor and said conduit of Au, with said sensor and conduit second layers bonded to each other. 32. The MFM of claim 31, wherein each said sensor comprises a respective semiconductor chip, further comprising an oxide of said semiconductor interfacing between said sensor and said first sensor layer. 33. The MFM of claim 23, wherein said electric circuitry senses the temperature within said conduit as a function of the sensor resistance. 34. The MFM of claim 23, wherein each said sensor is mounted to the outer surface of said conduit in thermal communication with a fluid flowing through the conduit. 35. The MFM of claim 23, wherein each said sensor is mounted within a respective opening in a wall of said conduit. 36. The MFM of claim 23, wherein each said sensor is mounted to an inner surface of said conduit. 37. The MFM of claim 23, wherein each said sensor is mounted inside said conduit on a protective shield and protected by said shield from the environment within said conduit. 38. The MFM of claim 23, wherein each said sensor projects into the interior of said conduit. 39. The MFM of claim 23, wherein said temperature sensors are electrically connected in a bridge circuit. 40. The MFM of claim 39, wherein said sensors are connected directly to each other in said bridge circuit. 41. The MFM of claim 39, said bridge circuit incorporating a pair of upstream temperature sensors and a pair of downstream temperature sensors. 42. The MFM of claim 23, further comprising a control valve governing the fluid flow through said conduit under the control of said circuitry. 43. A fluid temperature sensor, comprising: a conduit, and a plurality of discrete temperature sensors on said to a conduit in upstream and downstream sensor pairs, with the sensors of each pair located the same distance along the conduit's length and symmetrically on opposite sides of the conduit from each other, each said sensor electrically connected to sense the temperature of a fluid flowing through said conduit. 44. The fluid temperature sensor of claim 43, wherein each said temperature sensor is bonded to said conduit through a thermally conductive insulator. 45. The fluid temperature sensor of claim 43, wherein said upstream and downstream temperature sensors are connected in a 4 sensor bridge network. 46. The fluid temperature sensor of claim 45, wherein said sensors are connected directly to each other in said bridge circuit. 47. The fluid temperature sensor of claim 43, implemented as a mass flow meter which uses said sensed temperature as an indication of the mass flow rate of a fluid flowing through said conduit, further comprising a controller connected to control said fluid flow rate as a function of the indicated mass flow rate.
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