GB1145077A - Improvements in or relating to burner control apparatus - Google Patents

Abstract

1,145,077. Controlling burners. HONEYWELL Inc. 14 April, 1966 [19 April, 1965; 3 Sept., 1965; 3 March, 1966], No. 16463/66. Heading F4T. [Also in Division G1] A burner is controlled in dependence on its temperature and the level of carbon monoxide in the surrounding atmosphere using a sensor sensitive to both temperature and carbon monoxide. The sensor 13, Fig. 14, is housed in a chamber 21 adjacent the burner 20 and is connected to control a valve 18 in the fuel supply to the burner. Air and carbon monoxide flows into the chamber 21 through an aperture 14 and then into the burner body 11 through inlet 15 where it is mixed with the fuel and subsequently ignited. A bimetallic strip 16 may be provided in the housing 21 to control the intake of air dependent on the temperature at the burner, so that, for normal operation of the burner, the temperature of the sensor is maintained substantially constant and its output is dependent on the carbon monoxide content of the atmosphere. For abnormal operation, e.g. producing abnormally high or low temperatures, the sensor is sensitive to temperature as well. In a second embodiment of the burner apparatus, Fig. 15 (not shown), the air flowing into the housing surrounding the sensor 13<SP>1</SP> does not flow into the burner body. The sensor comprises a piece of a metal oxide, e.g. stannous or stannic, zinc, nickel, tungsten, antimony, copper oxide, or other material whose resistance or capacitance changes with temperature and carbon monoxide content in the surrounding atmosphere. In one embodiment, utilizing the change in resistance of an oxide, a thin layer or film 11, Fig. 1, of oxide is deposited on an insulating substrate 10, e.g. of glass or ceramic material. Two-electrodes 12, 13, e.g. thin layers of gold, are deposited one at either end of the film. Alternatively, Fig. 3 (not shown), the electrodes 12, 13 may take the form of a plurality of connected fingers extending towards each other. In a second embodiment, utilizing the change of dielectric constant of the oxide, an oxide film 11, Fig. 2 (not shown), is sandwiched between two layers of metal 12, 13, acting as electrodes, the electrode 12 being deposited on the substrate 10 and the electrode 13 being a thin gaspermeable layer of gold. In all embodiments, if a sufficiently thick layer of oxide is used, the substrate 10 may be omitted.