Abstract: A time delay switch has a hollow housing forming a liquid reservoir and having slidably disposed thereon an actuator movable between a switch open position and a switch closed position. The actuator is biased as by a suitable spring toward one of the switch open position and the switch closed position so that the actuator can be preset to one position so as to permit movement of the actuator toward the other position through the liquid reservoir under the bias of the spring in a predetermined period of time.

Abstract: An electronic circuit has been devised for precisely controlling the temperature of one zone in response to a change in temperature in another zone. Two sensors, one in each zone, are wired in opposing polarity so as to emit a signal when a temperature imbalance occurs. The circuit is designed to actuate a temperature controller in response to the signal. One application for the device is the establishment of adiabatic conditions for a reaction by controlling the temperature of the zone surrounding the reaction vessel to coincide with that within the vessel.