US3638489A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Stable ionization-type anemometer having an optimally adjustable measurement range
Assignee: Vyzkumny a Vyvojovy Ustav Zavodu Vseobecneho Strojirenstvi
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Filing: 1969-10-13
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Granted: 1972-02-01
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Expires: 1989-10-13
Abstract
Abstract A gas whose velocity is to be measured is passed through an ionization tube, and a first voltage proportional to the resulting ionization current is applied to one of two measurement arms of a bridge. A second voltage equal in magnitude to the first voltage when the velocity of the gas through the tube is zero is applied to a second arm of the bridge to set a zero reference on an ionization current meter connected between corresponding points on the measuring arms. The meter is then adjusted for full-scale deflection when the first voltage is reduced to zero to set the upper limit of the measuring range. The ionization current read on the meter during actual gas flow will now be accurately indicative of the flow velocity irrespective of the density and composition of the gas.
Inventors
- 👤 Vojtech Buran
- 👤 Jaromir Kuba
- 👤 Adolf Uncovsky
- 👤 Karel Zouhar
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 05:40
CPC Classifications
G; G01; G01P; G01P5/00; G01P5/005; G01P5/006; G01P21/00; G01P21/02; G01P21/025
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
128 words
A method of establishing a measuring range on a two-terminal deflection instrument employed to measure currents indicative of the velocity of flow of an ionizable gas, which comprises the steps of: directing the gas through an ionization tube which provides an output current inversely proportional to the velocity of flow of the gas; generating a test voltage proportional to the output current of the ionization tube; applying the test voltage to a first terminal of the instrument; applying to the other terminal of the instrument a reference voltage equal to the test voltage when the velocity of the gas through the ionization tube is zero to establish a zero reference for the measuring range; reducing the test voltage to zero; and then adjusting the instrument for maximum deflection.
Claim 2
Independent Claim
128 words
A method of establishing a measuring range on a two-terminal deflection instrument employed to measure currents indicative of the velocity of flow of an ionizable gas, which comprises the steps of: directing the gas through an ionization tube which provides an output current inversely proportional to the velocity of flow of the gas; generating a test voltage proportional to the output current of the ionization tube; applying the test voltage to a first terminal of the instrument; applying to the other terminal of the instrument a reference voltage equal to the test voltage when the velocity of the gas through the ionization tube is zero to establish a zero reference for the measuring range; reducing the test voltage to zero; and then adjusting the instrument for maximum deflection.
Claim 3
Dependent Claim
236 words
Apparatus for measuring a quantity indicative of the velocity of flow of an ionizable gas, which comprises: an ionization tube for receiving the flow of gas therethrough, the tube providing an output currenT inversely proportional to the velocity of flow of the gas; means for generating a test voltage proportional to the output current of the ionization tube; means for selectively short-circuiting the output of the generating means; a bridge circuit comprising, in combination, a pair of parallel measuring arms; a two-terminal deflection meter; first and second field-effect transistors each having a control gate and a source-drain path; a variable resistance for coupling one point in the source-drain path of the first transistor to one terminal of the meter; means for coupling a corresponding point in the source-drain path of the second transistor to the other terminal of the meter; a first resistance; a potentiometer; first means for serially connecting the source-drain path of the first transistor and the first resistance in one measuring arm; and second means for serially connecting the source-drain path of the second transistor and the main path of the potentiometer in the other measuring arm; means for applying the test voltage to the control gate of the first transistor; and means for coupling the center tap of the potentiometer to the control gate of the second transistor, the resulting current through the meter being indicative of the velocity of the gas.
Claim 4
Dependent Claim
236 words
Apparatus for measuring a quantity indicative of the velocity of flow of an ionizable gas, which comprises: an ionization tube for receiving the flow of gas therethrough, the tube providing an output currenT inversely proportional to the velocity of flow of the gas; means for generating a test voltage proportional to the output current of the ionization tube; means for selectively short-circuiting the output of the generating means; a bridge circuit comprising, in combination, a pair of parallel measuring arms; a two-terminal deflection meter; first and second field-effect transistors each having a control gate and a source-drain path; a variable resistance for coupling one point in the source-drain path of the first transistor to one terminal of the meter; means for coupling a corresponding point in the source-drain path of the second transistor to the other terminal of the meter; a first resistance; a potentiometer; first means for serially connecting the source-drain path of the first transistor and the first resistance in one measuring arm; and second means for serially connecting the source-drain path of the second transistor and the main path of the potentiometer in the other measuring arm; means for applying the test voltage to the control gate of the first transistor; and means for coupling the center tap of the potentiometer to the control gate of the second transistor, the resulting current through the meter being indicative of the velocity of the gas.
Claim 5
Dependent Claim
60 words
Apparatus as defined in claim 2, further comprising, in combination, means for coupling a predetermined bias voltage across the measuring arms of the bridge, and means for serially coupling the ionization tube and the generating means across the bias-voltage-coupling means, the control gate of the first transistor being connected to the junction of the ionization tube and the generating means.
Claim 6
Dependent Claim
17 words
Apparatus as defined in claim 2, in which the first serially connecting means comprises a variable resistance.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-01-31 | 1975-08-02 | 1976-02-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-01-31 | 1979-08-02 | 1980-02-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-01-31 | 1983-08-02 | 1984-02-01 | $7700.00 | Window Closed / Lapsed |