Patent GB-504102-A (GB)
Title: Improvements in blowpipes
IPC: B23K7/06
Filed: 1938-09-20
Abstract: 504,102. Blowpipe burners ; removing surface metal. LINDE AIR PRODUCTS CO. Sept. 20, 1938, No. 27342. Convention date, Sept. 23, 1937. [Class 75 (i)] [Also in Group XXII] A blow-pipe for thermo-chemically removing surface metal from steel slabs, blooms, billets, &c. comprises a flat narrow body 10 having a nozzle 20 projecting forwardly and downwardly from its lower edge, gas 'supply connections mounted on another edge, and a chamber for cooling liquid within the body from which air or gas can be vented through the cooling liquid passages when the blow-pipe is held at any angle. In the blow-pipe shown in Fig. 1, a fuel gas such as acetylene, and an oxidizing gas are supplied through connections 30, 31 and passages 46, 46 drilled in the body 10 to a mixing device 29 delivering into an annular chamber 27 communicating with the heating flame passage of the nozzle 20. Oxygen for desurfacing is supplied to the nozzle 20 through a connection 33 and a passage 36 drilled in a partition 35 dividing the cooling liquid chamber in the body 10 into two compartments A, B. Water or other cooling liquid is supplied to the compartment A through a connection 32 and two passages 38, 39, the passage 38 projecting water on to the mixing device 29 and the passage 39 projecting water towards the front wall of the chamber. The water so discharged passes through holes 42 bored in the partition 35, one on each side of the passage 36, to the compartment B and escapes through a drilled passage 44 and connection 34. Solid material collecting in the compartments A, B may be removed through openings normally sealed by plugs 47. A mounting bracket 12 is bolted to the rear edge 11 of the body, which edge is long relatively to the front edge 17. The mixing device 29 shown in Fig. 3, is formed with a central passage provided with a throat portion 49 connected by a tapering portion 51 to a larger portion 50. Above the throat portion the passage is stepped to receive a mixing element 55, a threaded locking ring 62 and a screw plug 63. Fuel gas passes from the passage 45 through holes 64 in the mixing device to the space between the plug 63 and ring 62 and then through a metering orifice 61 and bore 60 in the element 55 to the throat 49. Oxygen passes from the passage 46 through holes 65 in the mixing device and an annular passage 78 surrounding the element 55 to a gap between the bottom of the element 55 and the mixing device where it impinges perpendicularly on the fuel gas. The restricted gas passages prevent the transmission of flashbacks. When an entire side of a steel billet is to be desurfaced, a number of blow-pipes are mounted in a protecting shoe 72, Fig. 5, with their jets converging and slightly overlapping so that the slag formed is blown ahead of the oxygen streams. In some instances the streams may be directed to one side so as to project the slag away from a previously conditioned surface. The rear edges of the blow-pipes are held in position by pins 14 on the brackets 12 engaging sockets in the shoe bottom 69 and by screws 76 passing through holes in an arm 15 on the bracket. The front edges 17 are secured by pins 75 passing through a cross-bar 73 on the shoe into sockets 18 in the blow-pipe and held by set-screws 19. Fig. 6 shows an alternative blow-pipe construction in which the water is discharged from a passage 138 in the blow-pipe on to the mixing device 29 and can pass from the compartment A to the compartment B through a passage 42 in the partition 35 and a passage 142 drilled in a fillet 140 extending from the top to the bottom of'the chamber A<1>. A vent tube 144 in the chamber B leading to the passage 44 allows the escape of air when the blow-pipe is inverted.