IPC분류정보
국가/구분 |
United States(US) Patent
등록
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국제특허분류(IPC7판) |
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출원번호 |
US-0458062
(1989-12-28)
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발명자
/ 주소 |
- Bonne Ulrich (Hopkins MN)
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출원인 / 주소 |
- Honeywell Inc. (Minneapolis MN 02)
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인용정보 |
피인용 횟수 :
62 인용 특허 :
0 |
초록
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A non membrane-based overpressure proof gas pressure microsensor. It is not a membrane-based microsensor but is based on an open microbridge sensor structure. A method and apparatus is described to determine gas pressure from thermal conductivity, k, and volumetric specific heat, cpu, as well as pre
A non membrane-based overpressure proof gas pressure microsensor. It is not a membrane-based microsensor but is based on an open microbridge sensor structure. A method and apparatus is described to determine gas pressure from thermal conductivity, k, and volumetric specific heat, cpu, as well as pressure, P, using a microbridge sensor.
대표청구항
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An apparatus for determining fuel gas pressure using a non membrane-based microsensor for a gas at unknown conditions comprising: a non membrane semiconductor microbridge structure supported by a substrate having an electrically energizable heater film element thereon and resistive sensor film eleme
An apparatus for determining fuel gas pressure using a non membrane-based microsensor for a gas at unknown conditions comprising: a non membrane semiconductor microbridge structure supported by a substrate having an electrically energizable heater film element thereon and resistive sensor film element(s) located proximate to the heater film element such that said structure and substrate are so arranged and disposed so that they maintain contact. with the fuel gas of interest being immersed therein and such that when an electrical energy pulse source supplies an electrical energy pulse to said heater film element of sufficient time duration (also called pulse width) and power, the pulse causes a resulting transient temperature rise followed by a steady-state temperature (dU) in said gas of interest, to a degree detectable by said sensor element(s) such that said sensor element(s) produce an imbalance output corresponding to the voltage imbalance due to change in resistivity between said sensor element(s) and balancing resistor element(s); Whc measuring means for measuring heater power, Whc, required to achieve a constant differential, dT, above ambient temperature and for producing an output representative of this value Whc; S measuring circuit for measuring occurrences of changes in said imbalance output which are characteristic of the transient temperature rise signal, s, and means for determining its integral S for each occurrence and for producing an output representative of this value S; dU measuring circuit for measuring the amplitude of the steady-state temperature signal, dU, from said imbalance output and for producing an output representative of this value dU; Tg measuring sensor means for measuring gas temperature at the location of the structure substrate (Tg) and producing a signal representative thereof; a computing device connected to received said signals dU, Whd, Tg S, and employing signal processing circuitry, data, and processing components, said computing device configured to have k computing means, cp computing means and p computing means, having; k computing means for representing a function to compute thermal conductivity, k, of said gas of interest as a function of the measured signals representing dU, Whc and Tg (gas temp.); cp computing means for representing a function to compute specific heat, cp, as a function of the measured signals representing dU, Whc, S, and Tg; and p computing means for representing a function to compute pressure, P, of said gas of interest, according to a relation: P=Vmo (T/To) (Po) Cpv/cp where cp=specific heat, molar or weight -based and having been determined by said cp computing means, cpv=volumetric specific heat, measured Vmo=molar volume of ideal gases=22415 cm3/mol @0°C. and 1 atm T=sensed gas temperature in degrees K To=gas temperature at the reference condition of 0°F. or 273.15°K. Po=gas pressure at the reference condition of 1 atm, and an output device connected to said computing device which outputs said electrical signals representative of at least one of said k, cp, and P values.
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