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US 4,199,102 AGranted
Temperature control system
AssigneeDunham-Bush, Inc.
InventorSteven W. Paul
Life of this patent
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AssigneeDunham-Bush, Inc.
InventorSteven W. Paul
Estimating the term…
A temperature control system for monitoring and controlling a zone supplied with low-pressure steam is disclosed. The system utilizes a series of balanced Wheatstone bridges to provide a variety of automatic and manual control techniques to maintain temperature in the zone. Means are also provided to obtain direct readings of temperature, rate at which heat is being supplied, and the position and movement of a steam control valve which is utilized as a heat metering apparatus. The bridge leg outputs are permanently connected by high impedance coupling circuits which act as voltage dividers to obtain the required resultant control signals. High impedance coupling eliminates the need for control circuit balancing, thereby minimizing required calibrations in actual field use. The sole balancing calibration is with each sensor leg to a centered bridge leg.
In a balanced bridge control system for controlling the temperature in a space, said system having a source of heat and means to vary the rate at which heat is supplied, sensor means on a first bridge leg to determine the supply of heat to the space, sensor means on a second bridge leg to determine the demand for heat and a control circuit to alter the rate at which heat is supplied in response to the demand and supply sensor means, the improvement comprising high impedance coupling means for connecting said first bridge leg and said second bridge leg to said control circuit.
Dependencies are inferred from the claim text.