Patent GB-1107609-A (GB)
Title: Improvements relating to combustion devices
IPC: F23Q2/30
Filed: 1965-07-01
Abstract: 1,107,609. Spontaneous igniters. BATTELLE DEVELOPMENT CORPORATION. 1 July, 1965 [3 July, 1964], No. 27986/65. Heading F4F. A lighter comprises a tank 3 adapted to contain a fluid fuel, e.g. liquid gas, connected to a burner 4 by a wick within a tube 5, and a second tank 6 within the tank 3 adapted to contain a pyrophoric substance which may be delivered to the atmosphere in a limited quantity adjacent the fuel burner whereby by spontaneous combustion it ignites from the burner. The pyrophoric substance may be a liquid, e.g. trimethyl aluminium, or a gas, monosilane, or a vapour aluminium borohydride, and use may also be made of boron hydrides, silicon hydrides, metal alkyls and carbonyls. The pyrophoric substance is retained in the tank 6 by an absorbent material 11. A detachable cap B which when fitted over a part of the tank 3 closes the burner 4 by means of a plug 14 resiliently supports by means of a spring 17 a needle 12 which passes into the material 11 through the sealing washers 9. As the cap B is removed a limited quantity of the pyrophoric substance trapped in a cavity 12a in the end of the needle is withdrawn, and on reaching the atmosphere spontaneously ignites adjacent the burner. Washers 9 reseal the tank 6. In a modification, Fig. 4, the needle on being withdrawn passes into a combustion chamber 35 placed above the tank 6, the pyrophoric substance contained within the cavity 12a mixes with the air therein to cause a confined explosion accompanied by a jet of flame which emerges from an aperture in a wall of the combustion chamber. The burner 4, Fig. 3, comprises a nozzle 20 within a bush 19. In the closed position as illustrated the base 20a of the nozzle is pressed against a washer 21. When the nozzle is freed of pressure a spring 22 lifts it away from the washer and allows the fuel gas to escape to the nozzle outlet. In Fig. 5, the needle 12 is formed with an axial hollow channel and a metal rod 38 secured to the top of the cap B passes through it. As the needle is withdrawn from the tank 6 friction with the sealing plug 39 causes the needle to move down relative to the rod 38 compressing the spring 17, and the bottom part of the channel fills with the pyrophoric substance. As the needle leaves plug 39 the spring 17 expands pushing it up over the rod and ejecting the pyrophoric substance which ignites adjacent the burner nozzle. In the embodiment of Fig. 13, the top of the tank 6 is formed with a cylinder 150 having an aperture 154 normally closed by a piston 155 rigid with a rod 156 extending through the top end of the cylinder. The end of the rod 156 is rounded and is engaged by a tube 135 resiliently supported within the cap B. As the cap is withdrawn rod 156 is raised by the tube 135 and hence the piston exposes aperture 154. The pyrophoric substance in tank 6 enters the cylinder 150, explodes, and a jet of flames passes out through the aperture. A spring 158 within the cylinder above the piston becomes compressed during the above operation and finally exerts enough pressure to cause the rod 156 to be released from the tube 135 and the piston then reseals the aperture 154. Fig. 7 comprises a lighter having a hollow tubular body A closed at its top end by a metal disc 40 centrally through which extends a burner and from which eccentrically projects into the body A a tank 6 containing the pyrophoric substance. Sandwiched between the disc 40 and a further disc 48 is a rotatable disc 45 having an aperture 47 in communication with the tank 6. To ignite the burner the disc 45 is revolved against the action of a spring 62 until the aperture 47 which contains a limited amount of the pyrophoric substance registers with an aperture 51 in the disc 48 which is in communication with the atmosphere and is directed towards the burner nozzle. Rotation of the disc 45 also serves to open the fuel valve to the burner. In the lighter of Fig. 9, the cylindrical fuel container 3 has a burner nozzle 20 and the pyrophoric tank 6 extending through one end. The outer end of the tank 6 is capped by a domed hollow head 88a formed with an outlet aperture 89. An elastic member 93 is carried on a pivot 94 the ends of which slide in slots 95 formed in the upright portions 96 of a U-shaped member attached to the top of the container 3. In one stable position the member 93 closes both the nozzle 20 and the aperture 89. If the member is moved to an unstable portion 93b the nozzle 20 is opened and the aperture 89 is uncovered. The pyrophoric substance explodes in the domed head 88a. If the member is then released it assumes a second stable position 93a in which it recloses the aperture 89 only. In the embodiment of Fig. 11, the top of the pyrophoric substance tank 6 is connected by a flexible bellows joint 103 to a domed head 101 formed with an aperture 102 closed by a valve 104 secured to the top end of a rod 105 rigidly connected to the lower end of the tube 6. The fuel valve is opened by the lower edges 110a of the prongs 110 of a fork 107 bearing against the top of the burner nozzle 20 when the fork is moved towards the burner. An element 111 is caused to move towards the head 101 by engagement with a stop 119 projecting from the fork 107, and the lower edges 115 of said element depress the head 101 by compression of the bellows joint 103 and free the aperture 104 so that a limited quantity of the pyrophoric substance is ejected. The stop 119 is released from contact with the element 111 after the fork has been moved a calculated distance and the element is returned to its original position by the action of a spring 117 thus closing the aperture 102.