Boiler furnace ash hopper seal

Claim 1

IN A BOILER FURNACE INCLUDING A THERMALLY EXPANSIVE SECTION AND WHEREIN THE BOILER IS ADAPTED TO BURN SOLID FUEL AND PRODUCE A GASEOUS FLOW, A WATER-FILLED VESSEL WHICH SERVES AS AN ASH HOPPER FOR RECEIVING COMBUSTION BY-PRODUCTS ORIGINATING FROM SOLID FUEL-FIRED BOILER OPERATION, SAID VESSEL COMPRISING A METALLIC OUTER SHELL AND AN INNER REFRACTORY MEMBER, SAID METALLIC SHELL EXTENDING VERTICALLY ABOVE THE REFRACTORY MEMBER, MEANS FOR MAINTAINING A NORMAL WATER LEVEL IN THE VESSEL ABOVE THE REFRACTORY MEMBER AND IN CONTACT WITH THE METALLIC SHELL, A SEAL PLATE MEMBER ATTACHED TO THE THERMALLY EXPANSIVE SECTION OF THE BOILER, SAID SEAL PLATE MEMBER EXTENDING INTO THE WATER-FILLED SECTION OF THE VESSEL, AND SEAL MEANS LOCATED WITHIN THE VESSEL AND ABOVE THE REFRACTORY, SAID SEAL MEANS COOPERATING WITH THE SEAL PLATE TO PREVENT THE ESCAPE OF BOILER GASES INSIDE THE HOPPER TO THE SURROUNDING ATMOSPHERE, AND NOZZLE MEANS FOR SUPPLYING WATER TO SAID HOPPER AND FOR FILLING AND FLUSHING THE SEAL MEANS FREE OF ANY COMBUSTION BY-PRODUCTS DEPOSITED THEREIN.