US3842670A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Improvements in measuring the velocity of gases
Assignee: National Research Development Corp UK
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Filing: 1972-08-28
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Granted: 1974-10-22
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Expires: 1992-08-28
Abstract
Abstract A meter and a method of measuring the velocity of gas in a duct are described, and the volumetric flow rate may be also determined as well as the total volume of gas passed through the meter in a given time. In one form the meter has an ion source and two ion collectors, so that gas in the duct is first ionized and then passes the collectors. The source and the collectors are devised to present little or no impedance to gas flow. A voltage pulse is applied to the first collector and when the resulting change in the number of ions collected at the second collector is detected another pulse is applied to the first collector. The frequency of the pulses applied to the first collector is measured to give gas velocity. Measurement of the total volume of gas flow through the meter is by counting the said pulses. A specially shaped duct is also described to increase absolute accuracy with which volumetric flow rate and the total volume of gas passed through the meter can be determined without flow calibration.
Inventors
- 👤 T Brain
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 18:34
CPC Classifications
G; G01; G01P; G01P5/00; G01P5/08; G01F; G01F1/00; G01F1/704; G01F1/708; G01F1/7088; G01P5/005; G01P5/006; G01P5/083; G01P5/18; G01P5/20
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
116 words
A meter for making measurements related to gas flow, including ionizing means for ionizing at least part of a gas flowing along a duct, first and second electrode means for collecting ions spaced apart in the duct, a pulse generator adapted to apply, on receipt of a trigger signal, a pulse to the first electrode means to change the number of ions collected by the first electrode means, means for detecting resultant changes in the number of ions collected by the second electrode means and for passing a trigger signal to the pulse generator every time such changes are detected, and output means for providing an output signal related to the occurrence of the trigger signals.
Claim 2
Dependent Claim
116 words
A meter for making measurements related to gas flow, including ionizing means for ionizing at least part of a gas flowing along a duct, first and second electrode means for collecting ions spaced apart in the duct, a pulse generator adapted to apply, on receipt of a trigger signal, a pulse to the first electrode means to change the number of ions collected by the first electrode means, means for detecting resultant changes in the number of ions collected by the second electrode means and for passing a trigger signal to the pulse generator every time such changes are detected, and output means for providing an output signal related to the occurrence of the trigger signals.
Claim 3
Dependent Claim
16 words
A meter according to claim 1 wherein the means for ionizing gas includes a radioactive source.
Claim 4
Dependent Claim
19 words
A meter according to claim 2 wherein the radioactive source includes the isotope Americium-241 or the isotope mixture Strontium-90/Yttrium-90.
Claim 5
Dependent Claim
61 words
A meter according to claim 1 wherein the means for detecting changes in the number of ions collected by the second electrode means includes a detector circuit having a voltage output dependent on the number of ions collected and a trigger circuit responsive to changes in the voltage output of the detector circuit exceeding predetermined limits to provide a trigger signal.
Claim 6
Dependent Claim
22 words
A meter according to claim 1 wherein the first and second electrode means each include a group of at least two electrodes.
Claim 7
Dependent Claim
31 words
A meter according to claim 1 for measuring the velocity of gases wherein the output means provides an output signal which is indicative of the repetition frequency of the trigger signals.
Claim 8
Dependent Claim
44 words
A meter according to claim 1 for measuring the volume of gas passing along a duct wherein the output means provides an output signal which is indicative of the number of trigger signals occurring while the said volume of gas passes along the duct.
Claim 9
Dependent Claim
56 words
A meter according to claim 7 wherein there is a measured volume of duct between the first and second electrode means, and the meter includes first and second means for modifying the gas flow to provide substantially the same gas velocity over the cross section of the duct at the first and second electrode means, respectively.
Claim 10
Dependent Claim
73 words
A meter according to claim 8 wherein the first and second means for modifying gas flow include first and second portions of the duct in each of which the cross-sectional area of the duct becomes progressively smaller in the direction of gas flow until a constriction is reached and then becomes larger again, the first and second electrode means being positioned adjacent to the constrictions in the first and second duct portions, respectively.
Claim 11
Dependent Claim
16 words
A meter according to claim 8 wherein the means for ionizing gas includes a radioactive source.
Claim 12
Dependent Claim
26 words
A meter according to claim 10 wherein the pulse generator is adapted to supply pulses which are rectangular in wave form to the first electrode means.
Claim 13
Dependent Claim
120 words
A meter for making measurements related to gas flow including ionizing means for ionizing at least a part of a gas flowing along a duct in the region of the duct where the velocity of the gas is substantially constant, first and second electrode means for collecting ions spaced apart in the duct, control means for effecting a change in the number of ions collected by the first electrode means, and means for providing a signal dependent on the intervAl between the time at which a change in the number of ions collected by the first electrode means is effected and the time at which a resulting change occurs in the number of ions collected at the second electrode means.
Claim 14
Dependent Claim
120 words
A meter for making measurements related to gas flow including ionizing means for ionizing at least a part of a gas flowing along a duct in the region of the duct where the velocity of the gas is substantially constant, first and second electrode means for collecting ions spaced apart in the duct, control means for effecting a change in the number of ions collected by the first electrode means, and means for providing a signal dependent on the intervAl between the time at which a change in the number of ions collected by the first electrode means is effected and the time at which a resulting change occurs in the number of ions collected at the second electrode means.
Claim 15
Dependent Claim
55 words
A meter according to claim 12 for measuring the volume of gas passing along the duct, wherein the volume of the duct between the first and second electrode means is known, and means are provided for integrating the signal dependent on the said interval to provide a signal indicative of the volume of gas flowing.
Claim 16
Dependent Claim
40 words
A meter according to claim 13 including first and second means for modifying the gas flow to provide a substantially uniform gas velocity over the whole cross section of the duct at both the first and second electrode means, respectively.
Claim 17
Dependent Claim
73 words
A meter according to claim 14 wherein the first and second means for modifying gas flow include first and second portions of the duct in each of which the cross-sectional area of the duct becomes progressively smaller in the direction of gas flow until a constriction is reached and then becomes larger again, the first and second electrode means being positioned adjacent to the constrictions in the first and second duct portions, respectively.
Claim 18
Dependent Claim
29 words
A meter according to claim 14 wherein the control means includes a pulse generator adapted to supply pulses which are rectangular in wave form to the first electrode means.
Claim 19
Dependent Claim
120 words
A meter for measuring the velocity of gases or the volumetric flow rate of gases, including ionizing means for ionizing at least part of a gas flowing along a duct, first and second electrode means for collecting ions spaced apart in the duct, a pulse generator adapted to apply rectangular pulses to the first electrode means on receipt of a control signal to change the number of ions collected by the first electrode means, means for detecting resultant changes in the number of ions collected by the second electrode means and for passing a control signal to the pulse generator every time such changes are detected, and means for providing a signal indicative of the frequency of the control signals.
Claim 20
Dependent Claim
120 words
A meter for measuring the velocity of gases or the volumetric flow rate of gases, including ionizing means for ionizing at least part of a gas flowing along a duct, first and second electrode means for collecting ions spaced apart in the duct, a pulse generator adapted to apply rectangular pulses to the first electrode means on receipt of a control signal to change the number of ions collected by the first electrode means, means for detecting resultant changes in the number of ions collected by the second electrode means and for passing a control signal to the pulse generator every time such changes are detected, and means for providing a signal indicative of the frequency of the control signals.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-10-21 | 1978-04-22 | 1978-10-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-10-21 | 1982-04-22 | 1982-10-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-10-21 | 1986-04-22 | 1986-10-22 | $7700.00 | Window Closed / Lapsed |