US3874407A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Pulse width modulation control for valves
Assignee: Individual
•
Filing: 1974-01-02
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Granted: 1975-04-01
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Expires: 1994-01-02
Abstract
Abstract A control circuit for a fluid controller such as a solenoid driven valve. A pulse output system operating at a fixed or variable frequency, with pulse width varying as a function of error signal. An integrator for integrating the error signal and providing an input to a threshold trigger circuit, and a multivibrator for periodically grounding the integrator output.
Inventors
- 👤 Ray F Griswold
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 01:17
CPC Classifications
G; G05; G05B; G05B11/00; G05B11/01; G05B11/26; G05B11/28; Y; Y10; Y10T; Y10T137/00; Y10T137/8593; Y10T137/86389; Y10T137/86405; Y10T137/86421; Y10T137/87169; Y10T137/87217
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
93 words
A control circuit for a fluid controller, including in combination: first means for generating an error signal; first and second signal paths, each of said paths including an integrator, a threshold circuit and an output device; second means for connecting said error signal as an input to each of said integrators, with an integrator output connected to the corresponding threshold circuit which in turn provides an output signal to the output device when the integrator output exceeds the threshold level of the threshold circuit; and third means for periodically dissipating the integrator outputs.
Claim 2
Dependent Claim
93 words
A control circuit for a fluid controller, including in combination: first means for generating an error signal; first and second signal paths, each of said paths including an integrator, a threshold circuit and an output device; second means for connecting said error signal as an input to each of said integrators, with an integrator output connected to the corresponding threshold circuit which in turn provides an output signal to the output device when the integrator output exceeds the threshold level of the threshold circuit; and third means for periodically dissipating the integrator outputs.
Claim 3
Dependent Claim
37 words
A control circuit as defined in claim 1 wherein said first means includes a source of a command signal, a source of a feedback signal, and a summing unit having said command and feedback signals as inputs.
Claim 4
Dependent Claim
44 words
A control circuit as defined in claim 1 wherein said second means includes first and second unidirectional conducting elements, with said first element in said first path and said second element in said second path with a polarity opposite that of said first element.
Claim 5
Dependent Claim
25 words
A control circuit as defined in claim 1 wherein said third means includes a switching circuit for periodically connecting the integrator outputs to circuit ground.
Claim 6
Dependent Claim
29 words
a control circuit as defined in claim 1 wherein said third means includes a multivibrator unit sequentially connecting the outputs of the first and second integrators to circuit ground.
Claim 7
Dependent Claim
24 words
A control circuit as defined in claim 1 wherein each of said output devices includes a solenoid operated valve for control of fluid flow.
Claim 8
Dependent Claim
34 words
A control circuit as defined in claim 6 wherein a valve is opened during the period between the time an integrator output exceeds the threshold level and the time the integrator output is dissipated.
Claim 9
Dependent Claim
79 words
A control circuit as defined in claim 6 wherein said first means includes a summing unit for receiving a command signal and a feedback signal as inputs, said second means includes first and second unidirectional conducting elements, with the first element in said first path and said second element in said second path with a polarity opposite that of said first element, and said third means includes a switching unit for periodically connecting the integrator outputs to circuit ground.
Claim 10
Dependent Claim
21 words
A control circuit as defined in claim 1 wherein said third means includes means for controlling the duration of the periods.
Claim 11
Dependent Claim
86 words
A control circuit for a fluid controller including in combination: first means for generating an error signal; means defining a signal path including an integrator, a threshold circuit and an output device; second means for connecting said error signal as an input to said integrator, with the integrator output connected to the threshold circuit which in turn provides an output signal to the output device when the integrator output exceeds the threshold level of the threshold circuit; and third means for periodically dissipating the integrator output.
Claim 12
Dependent Claim
86 words
A control circuit for a fluid controller including in combination: first means for generating an error signal; means defining a signal path including an integrator, a threshold circuit and an output device; second means for connecting said error signal as an input to said integrator, with the integrator output connected to the threshold circuit which in turn provides an output signal to the output device when the integrator output exceeds the threshold level of the threshold circuit; and third means for periodically dissipating the integrator output.
Claim 13
Dependent Claim
27 words
A control circuit as defined in claim 10 wherein said first means includes a summing unit for receiving a command signal and a feedback signal as inputs.
Claim 14
Dependent Claim
25 words
A control circuit as defined in claim 11 wherein said third means includes a switching circuit for periodically connecting the integrator output to circuit ground.
Claim 15
Dependent Claim
22 words
A control circuit as defined in claim 12 wherein said output device includes a solenoid operated valve for control of fluid flow.
Claim 16
Dependent Claim
21 words
A control circuit as defined in claim 10 wherein said third means includes means for controlling the duration of the periods.
References Cited (Backward Citations)
US3419784A
Cited
US3659631A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-03-31 | 1978-09-30 | 1979-04-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-31 | 1982-09-30 | 1983-04-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-31 | 1986-09-30 | 1987-04-01 | $7700.00 | Window Closed / Lapsed |