TW200519334A - Safety device for non-load operation of electrical heating tube - Google Patents

Abstract

The present invention provides a safety device for non-load operation of an electrical heating tube, wherein the electrical heating tube is connected to a temperature fuse and further connected to a thermostat and a leakage breaker and finally connected to a power source. An indicator is connected to another end of the electrical heating tube. When power is supplied, the electrical current from the power source flows through the leakage breaker to the thermostat, which controls the heating period and heating temperature of the electrical heating tube that is arranged inside a heating device, and at the same time, the indicator is lit. In case the container in which the heating device is placed contains no water, the electrical heating tube inside the heating device undergoes non-load heating. Since the electrical heating tube is made of metal, continuous non-load heating causes heat transfer by conduction and convection through the surrounding air. In this situation, the temperature fuse detects the high temperature and opens the circuit to cut off the electrical current between the thermostat and the electrical heating tube and thus stopping heating operation of the electrical heating tube and protecting the electrical heating tube from being burnt out by the high temperature and avoiding firing of electrical wires and electrical leakage. At this moment, the indicator goes off to warn users of the non-load heating situation.