Abstract: A portable furnace for generating and circulating heat in wearing apparel. The furnace consists of a compact closed container for containing a liquid therein and a second container is received in the closed container and adapted to receive a heating element therein through an opening to the exterior. At least a portion of the exterior walls of the second container are exposed to the interiors of the compact container for heat transfer through the walls to a liquid contained within the compact container. A flexible liquid conduit has both ends thereof connected for circulation of heated liquid from the container through the conduit and a positive displacement pump is connected to the conduit for hand manipulation to circulate heated liquid from the compact container through the conduit on demand.

Abstract: A portable heater for generating and circulating heat in wearing apparel. The heater consists of a compact insulated case having a cavity therein which is adapted to receive a chemical heat cartridge which gives off heat through an exothermic chemical reaction when an activator or catalyst is added to the chemical content of the cartridge. A liquid reservoir is positioned in the case for radiant heat transfer from the chemical heat cartridge. A flexible liquid conduit has opposite ends thereof connected for circulation of the heated liquid from the reservoir in a closed circuit, and a pump is provided for circulating the heated liquid through the conduit on demand.

Abstract: A portable furnace for generating and circulating heat in wearing apparel. The furnace consists of a compact insulated case having a cavity therein which is adapted to receive slow burning solid fuel agglomerates for combustion. A liquid reservoir is positioned in the case for radiant heat transfer from the ignited fuel agglomerates in the cavity. A flexible liquid conduit has opposite ends thereof connected for circulation of the heated liquid from the reservoir in a closed circuit, and a pump is provided for hand manipulation to circulate the heated liquid through the conduit on demand.

Abstract: A boot warmer having a compact portable heater unit for burning solid fuel agglomerates. The heater unit includes a liquid reservoir in heat exchange relationship with the fuel agglomerates. A liquid conduit circulates the liquid throughout a boot or a boot liner by means of a hand manipulated pump. The heat exchanger or unit and pump are exposed and attached to the top of the boot, or in the case of a boot liner to the top of the boot liner, with the provision of means to attach the unit to the top outside of a boot casing.