Patent US2628417A successfully refreshed from Google Patents.
US3559882A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process digital control
Assignee: Reliance Electric Co
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Filing: 1969-03-20
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Granted: 1971-02-02
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Expires: 1989-03-20
Abstract
Abstract An oven is a load in a process and the control acts through a partly digital and partly analogue loop with a digital controller to control the temperature of the oven. The digital controller has a comparator with two inputs, one in the partly digital/analogue loop and the other from a set point generator which is used to change the set point and hence the temperature of the oven. This set point generator is controlled either manually or by a digital computer having a temperature-sensing feedback from the oven. The foregoing abstract is merely a resume of one general application, is not a complete discussion of all principles of operation or applications, and is not to be construed as a limitation on the scope of the claimed subject matter.
Inventors
- 👤 Howard E Jordan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 21:29
CPC Classifications
G; G05; G05D; G05D23/00; G05D23/19; G05D23/1917; G05B; G05B15/00; G05B15/02
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
171 words
A process digital control apparatus comprising, in combination: a load as a part of a process; an actuator connected to control a given condition of said load; a controller having first and second inputs to a comparator and said comparator connected to control said actuator; sensor means responsive to said condition of said load; a computer having a digital output; means connected to said sensor means and supplying a variable digital signal proportional to said condition of said load to one input of said controller to complete a fiRst control loop exclusive of said computer; a set point generator generating a digital set point signal; means connecting said set point signal to the other of said inputs of said controller to thus control the set point of said condition of said load; means including said computer to vary said digital set point signal; and a second control loop including means responsive to a condition of said process to control said computer and thus control said set point signal and said actuator.
Claim 2
Dependent Claim
171 words
A process digital control apparatus comprising, in combination: a load as a part of a process; an actuator connected to control a given condition of said load; a controller having first and second inputs to a comparator and said comparator connected to control said actuator; sensor means responsive to said condition of said load; a computer having a digital output; means connected to said sensor means and supplying a variable digital signal proportional to said condition of said load to one input of said controller to complete a fiRst control loop exclusive of said computer; a set point generator generating a digital set point signal; means connecting said set point signal to the other of said inputs of said controller to thus control the set point of said condition of said load; means including said computer to vary said digital set point signal; and a second control loop including means responsive to a condition of said process to control said computer and thus control said set point signal and said actuator.
Claim 3
Dependent Claim
22 words
Apparatus as set forth in claim 1, wherein said load is an oven, and including heating means applying heat to said oven.
Claim 4
Dependent Claim
23 words
Apparatus as set forth in claim 2, wherein said sensor means includes thermocouple means mounted to be responsive to heat inside said oven.
Claim 5
Dependent Claim
18 words
Apparatus as set forth in claim 1, wherein said load includes an oven with a fluid fuel burner.
Claim 6
Dependent Claim
23 words
Apparatus as set forth in claim 1, wherein said controller is a digital controller and has first and second inputs of digital signals.
Claim 7
Dependent Claim
16 words
Apparatus as set forth in claim 5, wherein said digital controller has an analogue output signal.
Claim 8
Dependent Claim
21 words
Apparatus as set forth in claim 1, including a valve connected to control the flow of a fluid to the load.
Claim 9
Dependent Claim
41 words
Apparatus as set forth in claim 1, wherein said comparator is a reversible counter counting up by one unit for digital input pulses on said first input and counting down by one unit for digital input pulses on said second input.
Claim 10
Dependent Claim
38 words
Apparatus as set forth in claim 8, wherein said controller includes a digital to analogue converter having an input from said reversible pulse counter and having an output connected to a current to pressure converter in said actuator.
Claim 11
Dependent Claim
27 words
Apparatus as set forth in claim 1, wherein said set point generator includes an oscillator and an operational multiplier to have a variable rate of output pulses.
Claim 12
Dependent Claim
25 words
Apparatus as set forth in claim 1, wherein said set point generator includes means to vary the repetition rate of said digital set point signal.
Claim 13
Dependent Claim
18 words
Apparatus as set forth in claim 11, wherein said means to control the repetition rate includes said computer.
Claim 14
Dependent Claim
30 words
Apparatus as set forth in claim 12, including means connecting said sensor means to said computer for adjustment of the set point in accordance with other conditions of the process.
Claim 15
Dependent Claim
39 words
Apparatus as set forth in claim 1, wherein said load is an oven, and including a fluid fuel burner supplying heat to said oven, and a valve is connected to control the flow of fluid fuel to said burner.
Claim 16
Dependent Claim
37 words
Apparatus as set forth in claim 14, wherein said actuator is a current to pressure converter, and valve controlling means to control said valve responsive to the amount of pressure supplied from said current to pressure converter.
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) | 1974-02-01 | 1974-08-03 | 1975-02-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-02-01 | 1978-08-03 | 1979-02-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-02-01 | 1982-08-03 | 1983-02-02 | $7700.00 | Window Closed / Lapsed |