Johnson Controls Gmbh

Thomas M Holloway

Richard N Laakaniemi

George J Janu

Scott B Bramow

Warren A Lederman

Ralph M Ley, Jr

Harold W Alyea

A dual thermostat apparatus includes two thermostats which generate fluid control signals proportional to room air temperature. The thermostats are matched leakport pressure sensors having a signal orifice and a bimetal lid element to generate back pressure signals linearly related to temperature. The bimetal elements have adjustment cams to set the reference position with respect to the orifice. The cams are connected to a common shaft and dial to provide simultaneous and opposite readjustment with respect to the reference pressures. The signals are applied to separate signal chambers of the duplex relay, with a pressure regulator connected to the heat signal chamber to limit the operative pressure level of the heating signal to a selected maximum switchover pressure. The duplex relay controls a pressure supply valve for supplying a proportional pressure signal to a common output line to pneumatic operators of a heating valve and a cooling valve. The regulator and duplex relay create a control in which the heat pressure signal operates to one side of said reference pressure and the cooling signal controls to the opposite side of such reference pressure. The position of the cams sets the required temperature related movement before the operative back pressure signal is established and thus defines a dead band region in which neither heating or cooling is provided. The signal switchover becomes operative only in accordance with the dead band setting and thus a range in which neither the heating valve or cooling is actuated to conserve energy.

Dual thermostat control apparatus with dead band response

A control valve includes a single diaphragm as a common wall between an input signal chamber having an input port and an output chamber having a central supply port and an exhaust orifice. The orifice has a seating face parallel to and spaced from the diaphragm. A spring-loaded ball valve unit in the supply passage is aligned with an operator moving with the diaphragm. An increasing input signal first moves the diaphragm to close the exhaust orifice and thereafter moves the operator to open the supply valve. Pressure builds in the output chamber, tending to return the diaphragm and close the supply valve until the output and pilot pressure are balanced. The supply valve then closes. As the exhaust is sealed off, this effectively seals the output chamber. If the signal decreases, the diaphragm uncovers the exhaust orifice until a new balanced state is created. In high flow capacity systems a multiplicity of exhaust orifices are employed to match exhaust and supply flow capacity while maintaining minimal leakage.

Fluid relay apparatus

An environmental air distribution control system regulates the flow of air under pressure by using the system pressure itself to effect the desired control. This is accomplished by using one or more pressure regulating valves, each pressure regulating valve being adapted to selectively vary the pressure drop across its output impedance to thereby control the rate of flow of air.

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Mukwonago, WI, United States of America

Thomas M Holloway