GB550683A - Improvements in the working of mineral or mineral-like bodies - Google Patents

Abstract

550,683. Blowpipe burners. LINDE AIR PRODUCTS CO. April 17, 1940, No. 6904. Convention date, April 18, 1939. [Class 75 (i)] [Also in Groups XXI and XXII] Mineral or mineral-like masses are cut, bored or grooved by supplying to a zone on or within the mass at least one oxidizing gas stream and one fuel gas stream which mix within said zone and burn to melt or spall the material, from said mass, the melted or spalled material being removed as the flame advances along the desired path. For drilling rock by spalling, a blowpipe B, Fig. 1 is supplied through conduits A, O, C, W, respectively, controlled from a central valve stand V, with acetylene and oxygen for fuel, and compressed air and water, continuously or intermittently, for removing the spoil and cooling the blowpipe. In the conduit A is a powder dispenser P, with a check valve D, which may supply a solid such as Fe, Al, or mixtures thereof, which oxidize exothermically, and may have a byepass F. A shield S may surround the borehole to catch spallings and may have water-spray means E. The spoil may be removed by suction. The process may be used for enlarging boreholes for blasting. Where the material is fusible, operations may be facilitated by supplying fluxes such as Ti, Al, Mn, Mg, Fe, Si, or mixtures thereof, with or without halides &c. of alkali, ar alkaline earth metals ; air alone may be used to remove spoil from the melting zone, outside which water, or an air-water mixture, may be supplied to quench the molten material, break it up and eject it. Fe or Al may be used as a flux together with 1 to 35 per cent. by weight of one or more materials such as Mn, Si, Ti, Zr, alkali or alkaline earth metals, Mg, Al, Fe, or alloys, or oxides carbonates or other salts thereof, or Al, Si, ferrosilicon, Zr or Ca may form the major portion of the flux. Powdered metals or compounds coated with Al may also be used. Boring may be intermittent and the slag removed mechanically during halts. Air may be supplied for secondary combustion of the fuel, and if this does not completely remove the slag intermittent large blasts of air are supplied. In Fig. 3 the copper tip T of the blowpipe has a conical bore 138 leading through a chamber 132 to forwardly converging passages 133 leading oxygen &c. towards the central acetylene &c. pipe 154 ; a pipe 144 carries spoil-removing fluid to rearwardly directed ports 139 and surrounding it is a cooling jacket comprising an outer tube 143 and an inner baffle 151 spaced therefrom by outwardly bent parts 149, water &c. being admitted and removed through openings 122, 123, respectively, some of the water &c. escaping through radial passages 142. The blowpipe may have radial fins for centring. Specification 494,218 is referred to. The Specification as open to inspection under Sect. 91 states that in place of a gas flame, heating may be effected by electric arcs to which a flux may be supplied by a gas which may be used to oxidize the flux, and the process may be used for operating on metals. In Fig. 4 (Cancelled) a blowpipe, comprises a copper &c. tip T held to a body B by a threaded pipe 30<SP>1</SP> inclined relatively to inner and outer pipes 31<SP>1</SP>, 36<SP>1</SP> respectively. Oxygen &c. is admitted from nipple 35' to pipe 31', and acetylene, with or without powder, is admitted to pipe 30<SP>1</SP>, while air, water, or air and water mixtures pass through pipe 36' to rearwardly inclined passages 29<SP>1</SP> for removing spoil; some of the air, water or mixture may pass through a closable atomizer 41<SP>1</SP> to blow spoil away from the operator and a water jacket may be provided for the blowpipe. In Fig. 8 (Cancelled) the inner pipe 55' terminates in a conical nozzle 58' with annular rows of passages 61<SP>1</SP>, 62<SP>1</SP>, the nozzle having spacing ribs 63' engaging the conical forward opening in the tip T'. In Fig 17 (Cancelled) acetylene &c. is supplied through a central pipe 187 to a conical aperture 173 in the tip T", and also through pipe 182 and apertures 179, 176, to conical openings 177 in the tip, while oxygen, air &c. passes through an intermediate pipe 186 to the conical aperture 173 and also through passages 178 to the conical apertures 177; spoil-ejecting fluid supplied to the outer casing flows forwardly within a baffle 185 and then back outside the baffle to outlets 181. This subject-mater does not appear in the Specification as accepted.