Abstract: A heating apparatus comprises a closed vessel having thermally conducting walls and containing a gas that is heated by one or more electrical heating elements in the vessel. The vessel is received in a duct through which air is blown. The air is heated by the heat transferred to the vessel walls by the gas in the vessel. Pressure and thermostatic switches in the circuit of the heating element communicate with the gas in the vessel and provide a double-safety, over-temperature power shut-off. The heating apparatus may be used to blow hot air into water in a tub through hoses leading to inlet openings or to an air distribution mat placed in the tub. The bubbles of hot air heat the water and produce strong agitation. A special raft receives the air distribution mat, which heats water in the raft by bubbling hot air through it. The heating apparatus can also be used for space heating, warming and drying towels and clothes, hair drying and grooming animals.

Abstract: A central space heating apparatus comprises a furnace having a chamber adapted to receive and contain a gas and a source a heat for heating the gas in the chamber, conduits connected in closed circuit to the furnace chamber for conducting the gas from the chamber and returning it to the chamber, helium gas filling the chamber and the conduit circuit under a pressure of from about 25 psig to about 100 psig at the operating temperature of the apparatus, a fan for circulating the helium gas through the conduit circuit and the furnace chamber, and a multiplicity of convector means connected in the conduit circuit for flow of the helium gas therethrough and installed at selected locations in the space to be heated for transferring heat from the flowing helium gas to the space.

Abstract: A very simple and inexpensive heat exchanger comprises a closed vessel having thermally conducting walls and helium gas within the vessel. The helium gas is a heat transfer medium between a source of heat or cold and the vessel walls and the vessel walls are a heat transfer medium between the helium gas and a fluid in contact with the walls to be heated or cooled.

Abstract: An electric fluid heating apparatus includes a closed hollow metallic vessel filled with substantially pure gaseous helium at a pressure from about 30 psl absolute to about 100 psl absolute. At least one electric resistance heating element is disposed in the vessel and surrounded by the pressurized helium which acts as a heat transfer medium to conduct heat from the resistance element to the vessel walls by conduction and convection. The vessel is positioned within a closed container having walls spaced from the vessel to define a fluid flow path for the fluid to be heated. A baffle between the container and vessel divides the flow path into an inlet chamber in which the fluid entering the flow path is preheated and an outlet chamber in which the fluid is heated by contact with the vessel walls prior to discharge from the container through a metal outlet conduit passing through the vessel in contact with the helium for transfer of additional heat to the fluid.