Patent GB-625074-A (GB)
Title: Improvements in and relating to blow-pipes or cutting torches for flame cutting or removing of metal
IPC: F23D14/42
Filed: 1946-12-20
Abstract: 625,074. Blowpipe burners. BUCKLE, L. G., and BOOCOCK, R. Dec. 20, 1946, No. 37468. [Class 75(i)] [Also in Group XXIX] In a flame cutting torch of the type wherein a mixture of combustible gas and oxygen provides a pre-heating jet and a separate flow of oxygen provides a cutting jet, a pre-set fixed flow of balanced gaseous mixture is supplied at all times to the pre-heating jet sufficient to ensure proper heating during the cutting period and a supplementary flow of balanced gaseous mixture is supplied to the pre-heating jet to augment the pre-set fixed flow automatically on discontinuance of the cutting. Heating oxygen passes by an injector nozzle 10 into a mixing chamber 12 from a tube 22 which is connected to an oxygen supply line 1 (Fig. 1) through an oxygen pre-set fixed supply line 4 and an oxygen supplementary supply line 5. The oxygen pre-set fixed supply line 4 has no means, such as a valve, for controlling the flow therethrough but the oxygen supplementary supply line 5 includes a valve 13 which can be opened or closed to control the supply of supplementary oxygen. Fuel gas is supplied to the mixing chamber 12 by a similar arrangement comprising a fuel gas constant supply line 15 having no controlling means and a supplementary fuel gas supply line 16 including a valve 20 which can be opened or closed. The fuel gas supply line 14 leading to the fuel gas supply lines 15, 16 is provided with a valve 19 to open or close the supply of fuel gas to the torch and the heating oxygen branch 2 leading to the oxygen supply lines 4, 5 is provided with an adjustable valve 9 which is used to proportion the oxygen and fuel gas to produce a neutral pre-heating flame. Cutting oxygen is supplied to the nozzle of the torch through a pipe 21 which includes a cutting oxygen valve 6 which opens or closes to control the supply of cutting oxygen. The valve 13 in the oxygen supplementary supply line 5 and the valve 20 in the supplementary fuel gas supply line 16 are rotary type valves and are connected by gears to the shaft of the cutting oxygen control valve 6 which is also a rotary type valve, so that when the cutting oxygen control valve 6 is closed by rotating a lever 6d on the end of its shaft the valves 13, 20 open automatically to supply a supplementary supply of combustible mixture to the torch. The valves 6, 9, 13, 20 may be incorporated in a single valve block 25 mounted on the handle 26 of the torch. The heating oxygen discharges through a nozzle 10 at the end of the tube 22 into a Venturi mouth 11 on the mixing chamber 12 and assists in drawing the fuel gas into the Venturi mouth from an annular conduit 17 surrounding the oxygen tube 22. To this end the nozzle 10 is provided with a plurality of spaced peripherally disposed axially aligned grooves 10b. The mixture of heating oxygen and fuel gas passes from the mixing chamber 12 to the burner nozzle where it is discharged through an annular jet 18 surrounding a jet for the cutting oxygen. To ensure a correctly balanced supply of gaseous mixture restrictives 23, 24 are inserted in the lines 4, 15 supplying the pre-set fixed flows of heating oxygen and fuel gas, and the sizes of the ports in the valves 13, 20 are selected so that the supplementary flows of heating oxygen and fuel gas are also similarly proportioned. The restrictives 23, 24 may be short bores drilled in the valve blocks 25 or they may comprise threaded jets screwed into bores in the valve block. Corresponding variation of the supplementary fuel mixture may be made available by providing a plurality of valve members having different bores for the valves 13, 20. Simultaneous control of the supplementary flows of oxygen and fuel gas may take the form of pressure responsive mechanism operated by the flow of cutting oxygen.