Heat accumulator

Claim 1

A heating system comprising a heat accumulator arranged in heat exchange relation with a heating boiler containing a fluid having a relatively low boiling point to be heated for use, said heat accumulator comprising a body of a material having a high heat capacity and a high melting point which is arranged for being heated by electric energy to a temperature considerably higher than the maximum temperature of said boiler, and an electric heating means for heating said body; said body including a conduit containing a fluid in a liquid phase having a relatively low boiling point; the fluid in said conduit being arranged in heat transferring communication with the fluid in said boiler for heating said boiler fluid; and a circulation pump having the suction side thereof in communication with an expansion vessel and said boiler, said expansion vessel being vented to the atmosphere; means responsive to the temperature of the fluid in said boiler for controlling the starting and stopping of said pump; said conduit having a predetermined volume which is relatively small as compared to the capacity of said pump; said pump having a relatively high initial startup speed to initially drive any vaporized fluid out of said conduit, and being designed and arranged to return to a relatively lower, second speed for normal operation after said initial startup; and said pump being stopped if a predetermined temperature is reached in said boiler thereby creating in said conduit of said body of said heat accumulator dry vaporized fluid of moderate pressure as established by said expansion vessel.