US4276773A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Gas flow measuring apparatus
Assignee: Soken Inc
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Filing: 1979-12-11
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Granted: 1981-07-07
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Expires: 1999-12-11
Abstract
Abstract A gas flow measuring tube is provided in a duct through which gas to be measured is flown. In this gas flow measuring tube there are placed an electric heater and first and second temperature dependent resistors which are formed of resistance wires stretched across a plurality of respective insulator frames. A measuring circuit is provided for controlling electric power to be supplied to the electric heater in accordance with the resistance change of the temperature dependent resistors, and thereby measuring the amount of the flow of gas to be measured. The measured values are corrected in accordance with the temperature of the insulator frames.
Inventors
- 👤 Hisasi Kawai
- 👤 Tsuneyuki Egami
- 👤 Tokio Kohama
- 👤 Hideki Obayashi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 06:21
CPC Classifications
G; G01; G01F; G01F1/00; G01F1/68; G01F1/684; G01F1/688; G01F1/69; G01F1/696; G01F1/698
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
211 words
A gas flow measuring apparatus comprising: a gas flow measuring tube provided in a duct through which gas to be measured is flown; an electric heater provided in said gas flow measuring tube; a first temperature dependent resistor provided in said gas flow measuring tube on the downstream side of said electric heater; a second temperature dependent resistor provided in said gas flow measuring tube at a position where there is substantially no thermal effect of said electric heater, said electric heater and said first and second temperature dependent resistors each including an insulator frame and a resistance wire stretched across said frame; a temperature compensation resistance means provided in said gas flow measuring tube, and which exhibits a resistance value indicative of the temperature of said insulator frame; and a measuring circuit connected with said electric heater, said first and second temperature dependent resistors and said temperature compensation resistance means, for controlling electric power to be supplied to said electric heater in accordance with resistance change of said first and second temperature dependent resistors so as to measure the amount of flow of gas to be measured, the control of power supply to said electric heater being corrected in accordance with the resistance value of said temperature compensation resistance means.
Claim 2
Dependent Claim
211 words
A gas flow measuring apparatus comprising: a gas flow measuring tube provided in a duct through which gas to be measured is flown; an electric heater provided in said gas flow measuring tube; a first temperature dependent resistor provided in said gas flow measuring tube on the downstream side of said electric heater; a second temperature dependent resistor provided in said gas flow measuring tube at a position where there is substantially no thermal effect of said electric heater, said electric heater and said first and second temperature dependent resistors each including an insulator frame and a resistance wire stretched across said frame; a temperature compensation resistance means provided in said gas flow measuring tube, and which exhibits a resistance value indicative of the temperature of said insulator frame; and a measuring circuit connected with said electric heater, said first and second temperature dependent resistors and said temperature compensation resistance means, for controlling electric power to be supplied to said electric heater in accordance with resistance change of said first and second temperature dependent resistors so as to measure the amount of flow of gas to be measured, the control of power supply to said electric heater being corrected in accordance with the resistance value of said temperature compensation resistance means.
Claim 3
Dependent Claim
29 words
A gas flow measuring apparatus according to claim 1, wherein said temperature compensation resistance means includes another insulator frame and a resistance wire wound around said another insulator frame.
Claim 4
Dependent Claim
38 words
A gas flow measuring apparatus according to claim 1, wherein said temperature compensation resistance means includes a resistance wire wound around one of the insulator frames of said electric heater and said first and second temperature dependent resistors.
Claim 5
Dependent Claim
38 words
A gas flow measuring apparatus according to claim 1, wherein said temperature compensation resistance means includes a film-shaped resistor deposited onto one of the insulator frames of said electric heater and said first and second temperature dependent resistors.
Claim 6
Dependent Claim
39 words
A gas flow measuring apparatus according to claim 1, 2, 3 or 4, wherein said temperature compensation resistor means is inserted in a bridge circuit which is formed of reference resistors and said first and second temperature dependent resistors.
Claim 7
Dependent Claim
68 words
A gas flow measuring apparatus according to claim 1, 2, 3 or 4, wherein said measuring circuit includes a differential amplifier circuit having input terminals to which are applied a predetermined reference voltage and a voltage corresponding to the resistance change of said first and second temperature dependent resistors, said temperature compensation resistor means being connected to the input terminal to which said predetermined reference voltage is applied.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-07-06 | 1985-01-05 | 1985-07-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-07-06 | 1989-01-05 | 1989-07-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-07-06 | 1993-01-05 | 1993-07-07 | $7700.00 | Window Closed / Lapsed |