Abstract: An improved ceramic burner plate for gas combustion which is made from a composition comprising about 30-40 weight percent of a clay, about 3-8 weight percent of talc, about 25-40 weight percent of a pore-producing substance and about 14-36 weight percent of mullite. The ceramic burner plates of the invention are characterized by excellent fire resistance and long service life.

Abstract: An oxygen sensing probe includes a substrate of sintered zirconia or titania, which is formed with a pair of elongate sensing elements integral with a bridging portion of the substrate, the sensing elements having rare-earth metal electrodes on opposite parallel faces thereof which terminate on the bridging portion, at which point they are connected to electrical leads.

Abstract: A safety apparatus for shutting down a room heating device upon detecting incomplete combustion in the burner of the heating device. A detecting element is arranged to provide an output to a setting circuit. When the output changes due to a change in combustion, the circuit cuts off fuel supply. Additional circuitry is provided to vary the predetermined operation level of the circuit depending on whether a room air circulation fan is operating or not.

Abstract: A combustion detecting element is provided which comprises an element body generating an electric change which corresponds to a difference in oxygen concentration between a first surface and a second surface thereof. Catalytic electrode layers are provided on both surfaces for carrying out catalytic reaction with combustible gas and a lead wire is connected to each layer, the catalytic electrode layers being characterized in that each catalytic electrode layer has substantially different capabilities in catalytic reaction with combustible gas.

Abstract: There is provided a combustion safety apparatus where the main burner has a combustion detecting element such as an oxygen concentration cell element, and the element is arranged so that one electrode thereof is always heated by a flame of a standing burner and into an oxygen lack condition while the other electrode is heated by the main burner. When the main burner is in its complete combustion condition, there is a difference in oxygen concentration between the two electrodes and thereby there is generated an output at the element. On the other hand, when the main burner is in its incomplete combustion condition, the difference in oxygen concentration therebetween is decreased and thereby the output is lowered. In addition there is provided a safety device such as a gas safety valve or the like.

Abstract: A combustion safety arrangement in which a switch is connected in an electrical power circuit for an electromagnetic valve in a fuel passage. A combustion detecting element responds to a change of a flame caused by incomplete combustion or the like, and generates a signal or change in an electrical characteristic. The switch and the combustion detecting element are interconnected through a control circuit which has a level detector for detecting a predetermined level of the change in electrical characteristics. The arrangement is such that the switch may be opened by the predetermined level of the change in electrical characteristics. The control circuit has a time limit operation circuit so that only when the generation of the change in electrical characteristic is continued for a delayed time set by that time limit operation circuit, the switch may be opened.