GB913060A - Automatic electro-magnetic control for oil fuel burners - Google Patents

Abstract

913,060. Liquid fuel burners. AUTOCOMBUSTIONS (LONDON) Ltd. May 13, 1960 [May 21, 1959], No. 17321/59. Class 75 (1). A system for injecting predetermined quantities of fuel oil into kilns at spaced time intervals comprises electrical means, Fig. 7, for producing pulses of current to energize an electromagnetic change-over valve 55, Fig. 2, which alternately connects a high pressure fuel inlet 63 and a low pressure fuel inlet 64 to two outlets 65, 66 and an injector valve, Fig. 4, having inlets 78, 79 connected to the outlets 65, 66 of the change-over valve and adapted to expel a predetermined quantity of fuel at high pressure at each change over of the pressure. The outlet 82 of the injector valve is connected to a pipe having a swaged down open end forming a lance located in the kiln. The change-over valve, Fig. 2, comprises a pair of solenoids 53, 54 energized alternately to move a double piston valve between two end positions in a cylinder 57 to which the high and low pressure inlets and outlets 63 ... 66 are connected. The two solenoids may be placed coaxially with their ends abutting and act on a single armature. The injector valve, Fig. 4, comprises a double piston valve 76 and an injection piston 69 both being moved by the difference in pressure between the fuels at the two inlets 78, 79 such that on reversal of the pressures at the inlets each moves from one end of its cylinder to the other end. In Fig. 4, the high pressure fuel is connected to the lower inlet 79 and when a reversal of pressures occurs the piston valve 76 moves downwardly to connect the duct 80 to the high pressure inlet 78 and to disconnect the duct 80 from the outlet 82 and to connect the duct 81 to the outlet 82. The injection piston 69 therefore moves downwardly and expels the fuel below it through the outlet 82. The amount of fuel displaced by each movement of the injection piston 69 is adjusted by means of adjustable screws (not shown) acting as end abutments for the piston. The injection valve may be modified by providing a third piston on the valve 76 and a second outlet connected to the low pressure line. When the injection piston 69 moves in one direction it expels fuel to the lance and when it moves in the other direction it expels fuel to the low pressure line. The electrical means, Fig. 7, for producing the pulses to energize the electromagnetic change-over valve comprises a thyratron V for periodically discharging a condenser C1 charged from D.C. mains through a switch selected resistor R1, 1, R2, R3. A relay RL connected in parallel with the condenser, operates contacts supplying the solenoids of the change-over valve and a changeover switch for the solenoids is actuated by a coil OC connected in the anode circuit of the thyratron. The relay RL also closes contacts RL1 to charge a condenser C2 so that a positive voltage is applied to the grid of the thyratron to cause it to strike. A plurality of injection valves for supplying a plurality of flexible pipes leading to lances in the kiln may be mounted on a two-wheeled trolley. A casing on the end of the trolley encloses a change-over electromagnetic valve and an electrical pulse producing apparatus for actuation of the change-over valve. Sleeves for stowing the lances may be provided on the trolley. The oil fuel is fed to a high pressure pipe by two pumps in parallel and to a low pressure pipe through a pressure relief valve from the high pressure pipe.