GB477679A - - Google Patents

Abstract

477,679. Photo-electric control of fuel supply for burners. SUPERHEATER CO., Ltd. July 5, 1937, No. 18623. Convention date, July 4, 1936. [Class 40 (iii)] [Also in Groups XI and XII] Relates to safety devices for boiler &c. heating installations, in which the supply of fluid or pulverized fuel to the burner is automatically cut off when the flame is extinguished. According to the invention, the supply of fuel is controlled by two devices such as valves 6, 7, both of which are under the control of a light-sensitive device 8 which responds to the influence of light from a flame in the furnace chamber, and one of the devices such as the valve 6 being also under manual control. The arrangement shown, where the devices 6, 7 are valves in an oil conduit 5, is such that in order to allow oil to pass to the burner 4, the valve 6 must first be manually opened and light from an igniting flame must be allowed to fall on the photo-voltaic cell 8 ; thereupon by the action of a relay or the like 12 controlled by the cell, the valve 7 is opened, and both valves 6, 7 are retained open so long as light from the furnace chamber falls on the cell 8. Both valves close automatically when the cell 8 ceases to be influenced by a flame. The operating spindle of the valve 6 carries an armature which, when the valve has been opened by means of a handle 10, is moved close to or in contact with the poles of an electromagnet. When this is energized through the relay 12 controlled by the cell 8, it is able to keep the valve open, though it has insufficient strength to attract the armature before the valve has been opened by hand. The valve 7 is under the sole control of the relay, and both valves are closed automatically, e.g. by springs, when the cell 8 is inoperative. The cell may be fixed at the end of a tube 16 directed towards the burner 4 ; mirrors may be used if necessary. The valves may be controlled by several photo-electric cells operating simultaneously. Expansion traps 17, 18 may be provided at the bottom or the top of the combustion chamber 2, to provide a safeguard against explosion. There is a small opening 21, for draining off unburnt fuel. The handle 10 may be actuated by connection with means for introducing the firing flame. Instead of controlling valves in the fuel feed conduit, the photo-electric cell may otherwise control the fuel supply, e.g. by controlling a motor for pumping fuel to the burner.