System for heating materials with electromagnetic waves

摘要

A system for controlling microwave heaters in order to efficiently heat frozen ground. The heaters are energized and deenergized by a control unit in response to the temperature sensed a selected distance from a heater. The control unit also deenergizes the heater in response to a temperature sensed in the vicinity of the applicators of the heater in order to protect the heaters from overheating.