Thermostatically controlled electric continuous water heating unit

摘要

An automatic continuous boiling water heater unit has a water heating tank incorporating an electric heating element near the bottom thereof and a float operated valve for feeding water to the heating tank from a level control tank mounted alongside the heating tank through a constricted conduit designed to allow a water flow rate substantially equal to the boiling water heating rate capacity of the element. A temperature control device, including a temperature sensitive probe surrounded by a metal gauge and positioned in a conduit communicating the level control tank with the heating tank above the water level therein maintained by the float operated valve, is provided for deenergizing the heating element when the water in the heating tank reaches boiling temperature. A safety cut-off switch responsive to a temperature sensitive capillary located in the path of steam discharged through a steam pressure safety valve at the top of one of the tanks deenergizes the heating element should the temperature control device fail. A safety vent tube having an inlet below the hot water discharge from the heating tank but above the heating element is arranged to direct steam onto the temperature sensitive capillary should the water supply to the heating unit fail.