Temp. controlled flow valve for dual heating system - has temp. sensors controlling bidirectional motor coupled to valve actuator

摘要

A two circuit heating system has temp. sensors located in the flow and return lines of the secondary circuit to control a bidirectional flow valve. Expansion elements (1, 2) located in the flow and return lines changes the output of variable resistors (3, 4). The outputs are used to provide push-pull control of a relay (13) via two coils (11, 12) in conjunction with a potentiometer (10). The potentiometer is coupled to the actuator stem (7) of a flow control valve (6). Bidirectional movement of the valve stem is provided by an electric motor controlled by the relay.