Abstract: In order to form a heating element, a coil-shaped hollow path, cut into a plate (10), is filled with an exothermally reacting pulverulent mixture and is compressed by means of a correspondingly shaped pusher (13), a platen being then applied to the upper face of the plate (10). Thereafter, the coil (2) comprised of compressed reactive mixture is lifted above the plate (10) and covered with a refractory powder to which a binder has been added and the assembly is then compressed by means of a piston (36; FIG. 6). The assembly is then placed into a metal container (5) intended to diffuse the heat for heating for example foodstuffs, after the reactive mixture has been ignited through the opening (22).

Abstract: The heating device for heating liquid and solid products comprises a heating element intended to heat a food preserve (314) or container structure. The heating element consists of a flat tile like element including a heat spreading layer (308) made of heat conducting material, an intermediate layer (303) composed by an exothermic gas-less combustible material and a layer of heat insulating incombustible material (301). The intermediate layer contains internal walls (302) defining a fire path in order to control the duration of the exothermic reaction. Ignition means comprises a cup-shaped primer (305) with in its center a protruding cone (307) and a starter (311) consisting of a striker arranged to be drawn across a friction sensitive element and intended to ignite the tip of said cone (307) of the primer (306), which in its turn induces the reaction to the combustible material (303).