Patent US4524906A successfully refreshed from Google Patents.
US4524906A
Expired / Lapsed
US
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Temperature control valve and sensor/controller therefor
Assignee: Parker Hannifin Customer Support Inc
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Filing: 1982-12-10
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Granted: 1985-06-25
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Expires: 2002-12-10
Abstract
Abstract A hot air modulating valve for mixing hot air with cold air flowing in a duct, the modulating valve having a torque motor operated pilot valve to position the modulator valve to maintain a predetermined temperature of the hot air-cold air mixture. The temperature of the mixture is sensed by a thermistor which in conjunction with a tri-mode (proportional plus integral plus derivative) electronic controller which provides an input current signal to the torque motor to position the modulator valve in proportion to the input current signal, produces zero steady state errors, and provides an anticipation effect to compensate for control system time lags. The controller has auxiliary inputs which when exceeding predetermined values switch the air mixture temperature at the thermistor to a lower setting. The modulating valve has a relatively low gain during the initial portion of its opening stroke to improve system dynamic stability and has a position feedback to the torque motor operated pilot valve.
Inventors
- 👤 Richard L. Kenyon
- 👤 Calvin E. Kempton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 15:12
CPC Classifications
G; G05; G05D; G05D23/00; G05D23/01; G05D23/13; G05D23/1393
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
226 words
An automatic process control system comprising control valve means providing a variable area orifice to change the rate of flow of a control agent to maintain a desired condition in the process, and a sensor/electronic controller of which the sensor detects a departure from the desired condition to produce an error signal which is processed by the controller to provide an output signal to said control valve means, said control valve means including a diaphragm actuated modulating valve, the diaphragm of which separates respective chambers on opposite sides thereof, means for providing system fluid to both said chambers for establishing a pressure differential on opposite sides of said diaphragm, said means for providing including motor operated pilot valve means for directing and controllably metering fluid flow to one of said chambers in response to actuation of said motor by said output signal to change the rate of flow of said control agent to restore the process to the desired condition, and means for venting system fluid from said one chamber to allow for such directed and controlled fluid flow to said one chamber, and said modulating valve having position feedback spring means bearing on said pilot valve means to reach a force equilibrium with the motor force acting on said pilot valve means when said modulating valve has stroked an amount proportional to said output signal.
Claim 2
Dependent Claim
226 words
An automatic process control system comprising control valve means providing a variable area orifice to change the rate of flow of a control agent to maintain a desired condition in the process, and a sensor/electronic controller of which the sensor detects a departure from the desired condition to produce an error signal which is processed by the controller to provide an output signal to said control valve means, said control valve means including a diaphragm actuated modulating valve, the diaphragm of which separates respective chambers on opposite sides thereof, means for providing system fluid to both said chambers for establishing a pressure differential on opposite sides of said diaphragm, said means for providing including motor operated pilot valve means for directing and controllably metering fluid flow to one of said chambers in response to actuation of said motor by said output signal to change the rate of flow of said control agent to restore the process to the desired condition, and means for venting system fluid from said one chamber to allow for such directed and controlled fluid flow to said one chamber, and said modulating valve having position feedback spring means bearing on said pilot valve means to reach a force equilibrium with the motor force acting on said pilot valve means when said modulating valve has stroked an amount proportional to said output signal.
Claim 3
Dependent Claim
27 words
The system of claim 1 wherein said means for venting includes an orifice operative to minimize sensitivity to variations in pressure downstream of said means for venting.
Claim 4
Dependent Claim
14 words
The system of claim 1 wherein said motor is housed within said one chamber.
Claim 5
Dependent Claim
18 words
The system of claim 1 wherein said pilot valve means controls the fluid pressure in both said chambers.
Claim 6
Dependent Claim
30 words
The system of claim 1 wherein said pilot valve means includes an orifice, and said motor is a torque motor having an armature operative to open and close said orifice.
Claim 7
Dependent Claim
26 words
The system of claim 1 wherein said controller has means providing an output signal for actuating said modulating valve in the proportional plus integral control mode.
Claim 8
Dependent Claim
28 words
The system of claim 1 wherein said controller has means providing an output signal for actuating said modulating valve in the proportional plus integral plus derivative control mode.
Claim 9
Dependent Claim
36 words
The system of claim 1 wherein said modulating valve is pressure balanced and is spring biased toward closed position when the force of the differential pressure on said diaphragm is less than the spring bias force.
Claim 10
Dependent Claim
115 words
The system of claim 1 wherein the temperature of a mixture of a hot fluid and a cold fluid is controlled, said control valve means being operative to change the rate of flow of one of the fluids to maintain a predetermined temperature of the mixture, said sensor being operative to detect a departure of the mixture from such predetermined temperature to produce the error signal processed by said controller, and said pilot valve means being operative in response to the output signal of said controller to position said modulating valve in proportion to the output signal to change the rate of flow of said one fluid to restore the mixture to the predetermined temperature.
Claim 11
Dependent Claim
20 words
The system of claim 9 wherein said sensor is a thermistor whose resistance decreases with increasing temperature of the mixture.
Claim 12
Dependent Claim
55 words
The system of claim 1 wherein said control valve means further has a fluid pressure inlet communicating via a restricted orifice upstream of said pilot valve means with the chamber on the side of said diaphragm opposite said one chamber and communicating via said restricted orifice and said pilot valve means with said one chamber.
Claim 13
Dependent Claim
29 words
The system of claim 11 wherein said pilot valve means is of the nozzle-flapper type, and said motor is a torque motor of which its armature constitutes said flapper.
Claim 14
Dependent Claim
160 words
An automatic process control system comprising a control valve providing a variable area orifice to change the rate of flow of a control agent to maintain a desired condition in the process; a sensor/electronic controller of which the sensor detects a departure from the desired condition to produce an error signal which is processed by said controller to provide an output signal to said valve; said valve having a diaphragm actuated modulating valve, and a motor operated pilot valve to establish a pressure differential on opposite sides of said diaphragm in response to actuation of said motor by said output signal to position said modulating valve in proportion to said output signal to change the rate of flow of said control agent to restore the process to the desired condition; and said controller having auxiliary signal inputs and signal processing means which, when said signal inputs exceed predetermined values, are operative to change the condition to which said sensor responds.
Claim 15
Dependent Claim
160 words
An automatic process control system comprising a control valve providing a variable area orifice to change the rate of flow of a control agent to maintain a desired condition in the process; a sensor/electronic controller of which the sensor detects a departure from the desired condition to produce an error signal which is processed by said controller to provide an output signal to said valve; said valve having a diaphragm actuated modulating valve, and a motor operated pilot valve to establish a pressure differential on opposite sides of said diaphragm in response to actuation of said motor by said output signal to position said modulating valve in proportion to said output signal to change the rate of flow of said control agent to restore the process to the desired condition; and said controller having auxiliary signal inputs and signal processing means which, when said signal inputs exceed predetermined values, are operative to change the condition to which said sensor responds.
Claim 16
Independent Claim
168 words
A system for controlling the temperature of a mixture of a hot fluid and a cold fluid comprising a control valve providing a variable area orifice to change the rate of flow of one of said fluids to maintain a predetermined temperature of the mixture; a sensor/electronic controller of which the sensor detects a departure of the mixture from the predetermined temperature to produce an error signal which is processed by said valve; said valve having a diaphragm actuated modulating valve, and a motor operated pilot valve to establish a pressure differential on opposite sides of said diaphragm in response to actuation of said motor by said output signal to position said modulating valve in proportion to said output signal to change the rate of flow of said one fluid to restore the mixture to predetermined temperature; and said controller having auxiliary signal inputs and signal processing means which, when said signal inputs exceed predtermined values, are operative to change the mixture temperature to which said sensor responds.
Claim 17
Independent Claim
168 words
A system for controlling the temperature of a mixture of a hot fluid and a cold fluid comprising a control valve providing a variable area orifice to change the rate of flow of one of said fluids to maintain a predetermined temperature of the mixture; a sensor/electronic controller of which the sensor detects a departure of the mixture from the predetermined temperature to produce an error signal which is processed by said valve; said valve having a diaphragm actuated modulating valve, and a motor operated pilot valve to establish a pressure differential on opposite sides of said diaphragm in response to actuation of said motor by said output signal to position said modulating valve in proportion to said output signal to change the rate of flow of said one fluid to restore the mixture to predetermined temperature; and said controller having auxiliary signal inputs and signal processing means which, when said signal inputs exceed predtermined values, are operative to change the mixture temperature to which said sensor responds.
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) | 1988-06-24 | 1988-12-24 | 1989-06-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-06-24 | 1992-12-24 | 1993-06-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-06-24 | 1996-12-24 | 1997-06-25 | $7700.00 | Window Closed / Lapsed |