A method for sealing a port in a wall through which an element is passed, comprising the steps of combining a water based fire-resistant liquid sealing material and a solid water absorbing means which will swell to prevent shrinkage to form a mixture that seals, and introducing the mixture into the port to seal the port. Materials and compositions for carrying out the method are disclosed.

A fail safe gas shut off system is provided for a gas appliance. Two normally closed valve stages are provided in series, with each stage operated by a bidirectional solenoid armature. When the armature moves in one direction, the first stage of the valve is opened to supply gas to a pilot burner and to the second stage of the valve. When the pilot flame heats an emissive element to produce sufficient radiation, a photovoltaic device illuminated by the emissive element produces current for an el...

An apparatus (1) is disclosed for controlling oxidation of a fuel in an oxidation source (2,3). The apparatus includes photovoltaic means (5) for receiving electromagnetic radiation (6) from the oxidation source and for producing electric power having a given electric power magnitude. An oxidation control (8, 1A, 1B, 288, 325) is coupled to, and driven, by, the photovoltaic means for controlling the oxidation. The oxidation is adjusted when the electric power is less than the given electric powe...

A thermophotovoltaic electric generating system provides high thermal to electric conversion efficiency by use of matched radiation emitter and radiation collector. The radiation emitter comprises ceramic materials which emit thermally stimulated quantum radiation in at least two characteristic wavelength bands when heated above a threshold temperature. By employing a low emissivity ceramic doped with rare earth metal oxide, more than 50% of the radiation emitted from the surface can be concentr...

Two photoelectric smoke detectors are arranged so that each smoke detector in turn verifies operation of the other smoke detector. Each smoke detector has a light source and a photodetector which is not directly illuminated by the light source. A smoke detection signal is issued when light from such a light source is scattered to the respective photodetector. The two smoke detectors are arranged so that a small amount of light from each light source illuminates the photodetector of the other smo...

A self-powered control system for a gas-fired appliance having a pilot burner and a main burner includes an emissive surface in the flame of the pilot burner and a photovoltaic device for irradiation from the emissive surface for providing electrical power for the control system. Two normally closed electromagnetic latching valves are arranged in series between a source of fuel gas and the main burner with a connection to the pilot burner between the two valves. The first valve is latched open w...

Embodiments of gas-fired appliances which generate sufficient electricity to be self-powered include water heaters, space heaters, air conditioning units, and electric power and steam cogeneration systems. In such apparatus, gas is burned in a porous ceramic surface combustion burner. The high temperature surface of the burner includes a narrow band quantum emitting substance such as a rare earth metal oxide and preferably ytterbium oxide. Relatively shorter wavelength radiation from this quantu...

The system utilizes a radiation sensing device which views an electrically heated emissive igniter to provide proof-of-ignitability detection of the igniter. Optimally a photovoltaic array may be employed to self-power the electronic circuitry and fuel intake valve to the burner of a combustion device. In one embodiment there is also provides a second emission device viewed by the first photovoltaic array or a second photovoltaic device which views a second emissive device which is thermally hea...

A tin oxide carbon monoxide sensor is operated in a manner to exclude effects of ambient temperature and humidity. Resistance of the sensor is measured at a lower temperature and again at a higher temperature. The target gas concentration is determined as a function of the first and second resistances, thereby cancelling the effects of humidity and ambient temperature.

The present invention relates to a biomimetic sensor for detecting the presence of airborne toxins, such as carbon monoxide, mercury, ethylene oxide, volatile organic materials, and hydrogen sulfide. The biomimetic sensor, which has a functional life of at least one year, comprises a porous, semi-transparent substrate into which is impregnated a self-regenerating chemical sensor reagent. The response of the biomimetic sensor mimics the human response to such toxins, with respect to sensitivity a...