Patent GB-664499-A (GB)
Title: Improvements in liquid fuel burners
IPC: F23D99/00
Filed: 1948-05-28
Abstract: 664,499. Liquid fuel burners. ANDERSEN, N. G. May 28, 1948 [June 9, 1947], No 14474/48. Class 75(i) The invention concerns a burner for selectively burning liquid fuel in atomized state at starting and liquid fuel in vaporized state during normal operating. The invention consists in that (1) the vaporizer is branched into the fuel and air passage system of the atomizer, is independently fed with fuel and is heated by the combustion of fuel at an outlet aperture communicating with the fuel and air passages of the atomizer or (2) the vaporizer is branched into the fuel and air passage system of the atomizer, is independently fed with fuel and means are provided for shutting off the supplies of air and fuel to the atomizer or (3) the vaporizer is branched into the fuel and air passage system of the atomizer, is heated by the combustion of fuel at an outlet aperture communicating with the fuel and air passages of the atomizer and a bowl is positioned below the atomizer to receive fuel that condenses on the vaporizer during preheating. As shown in Fig. 1 the burner comprises a fuel tank 10 fitted with a hand pump 30 and an air pressure release valve 20 in the filler cap. The vaporizer consists of a convex member 43 having two diametrical bores connected to pipes 38, 40, Fig. 2, ascending from a chamber 36 and to pipes 44, 46 leading to an adjustable space 60, Fig. 3, between a fuel discharge nozzle 48 and a plug 62 at the upper end of two-axial tubes 64, 78 supplying air and fuel to the nozzle at starting. The chamber 36 is screwed to a collar 92 fitted into an aperture in the top of the tank and communicates with the fuel through a pipe 34. The plug 62 is screwed into the top of the fuel supply tube 78 with its upper part a sliding fit in the coaxial air supply pipe 64; the air passes through bores 84 terminating in an annular groove 86 on the upper face of the plug. The burner discharge nozzle 48 which has recesses 72 with which the pins of a wrench are engaged is screwed into a socket 58 at the junction of the vapour supply pipes 44, 46. A needle 70 mounted on the end of a rod 82 extends through the outlet bore of the nozzle and serves both for cleaning and for regulation of the rate of burning. The two co-axial tubes 64, 78 extend downwardly through the chamber 36 into the fuel tank where the outer tube 64 terminates above the fuel and the inner 78 passes in sealed manner through the bottom of the tank. Fuel enters the inner tube through a bore 108 in a flange 106 on the tube near the bottom of the tank. The inlets to the coaxial tubes 64, 78 are controlled by a member comprising two tubes 134, 140 screwed together and slidably mounted on the inner co-axial tube 78 below the outer coaxial tube 64: The lower end of the tube 134 carries a fibre gasket 132 normally sealing the inlet channel 108 of the inner tube 78 and the upper end of the tube 140 contains a synthetic rubber packing 144 normally sealing the end of the outer tube 64. The packing 144 protrudes by a small amount from a sleeve 146 urged upwardly by a light spring 150 and the upper end of the tube 140 is turned inwardly to act as a stop for the packing. The two tubes 134, 140 are moved downwardly against a return spring 152 to open the inlets to the coaxial tubes by a crank 164 engaged with a flange 138 on the tube 134 and rotated by a spindle 156 extending through a sealed aperture in the side wall of the fuel tank. The inner coaxial tube 78 is in screw thread engagement over part of its length with the outer coaxial tube 64 so that by rotating the inner tube the space 60 between the burner nozzle and the plug 62 at the top end of the inner tube can be adjusted. The screw engagement of the tubes is traversed by two channels providing passage for the air supply. Rotation of the inner tube is effected by a tube 170 connected to the lower end of the inner coaxial tube below the bottom of the fuel tank and movement of the tube 170 between stops 178 spaced 120 degrees causes the space 60 to vary between a suitable maximum and a minimum which is almost zero. The tube 170 also serves as a sleeve for a flexible spindle 174 having a cranked end engaged with the end of the rod 82 carrying the cleaning and flame adjusting needle 70, Fig. 3. By rotating the spindle 174 the needle is reciprocated in the outlet bore of the burner nozzle 48. At starting the spindle 156 is turned to open the inlets to the co-axial tubes 64, 78 and the burner outlet bore is closed by the needle 70. Air is then pumped into the tank until the desired pressure is attained when the needle 70 is withdrawn to open the burner outlet bore. Atomized fuel is discharged and ignited to heat the vaporizer. Fuel which condenses on the cold vaporizer is collected in a bowl 180 mounted beneath the burner nozzle and this collected fuel burns to assist in the heating of the vaporizer. The bowl 180 may also serve as an air baffle in which case a number of air apertures are formed in its sides. A porous plate of asbestos may constitute the bowl. When the collected fuel is almost completely burned the inlets to the coaxial tubes 64, 78 are closed and the vaporized fuel passes to the nozzle. During preheating the space 60 is varied from a minimum at starting giving a rich easily ignited mixture to a maximum later giving a high temperature flame. Adjustment of the space 60 during normal operation provides, in conjunction with the needle 70, regulation of the rate of burning. To shut down the burner the controls are turned to their starting positions i.e. the inlets to the co-axial tubes 64, 78 are opened and the outlet bore is closed by the needle 70. A modified construction is shown in Figs. 8, 12. The vaporizer 208 is a ring shaped tube opening into the outer coaxial tube 64 below the burner nozzle and fed by a pipe 206 which is spaced from the coaxial tubes 64, 78. The opening and closing of the inlets to the coaxial tubes is effected by the tube 170 which also serves, as in the previous construction, to adjust the space 60' at the outlet nozzle. This arrangement dispenses with the separate crank control 156. The lower end of the inner coaxial tube 78 is provided near the bottom of the tank with a collar 254, Fig. 12, having an upward projection 256 with a bore 258 leading into the tube. This collar 254 co-operates with a tube 246 slidably mounted on the. inner coaxial tube 78 below the outer co-axial tube 64 and carrying at its upper end a spring urged packing 144 for closing the end of the outer coaxial tube 64. The lower end of the slidable tube 246 has a recess 248 the depth of which is slightly greater than the height of the projection 256 on the collar 254 so that with the projection disposed in the recess the aperture 258 is open but, by rotating the inner coaxial tube 78 by means of the tube 170 the slidable tube 246 is lifted and the aperture 258 is sealed by a gasket 262 on the end of the slidable tube 246. The inner coaxial tube 78 can be rotated by a limited amount without lifting the slidable tube 246 to permit the space 60 at the burner nozzle to be regulated at starting. The slidable tube is acted on by a spring 230 and is guided by the vaporizer supply pipe 206 extending through a bore 238 in a flange on the slidable tube. A U-shaped tube extends from a point above the burner nozzle to an incandescent mantle.