Patent GB-585952-A (GB)
Title: Improvements in processes of flame-machinery of metal bodies
IPC: B23K7/06
Filed: 1944-05-24
Abstract: 585,952. Blow-pipe burners. LINDE AIR PRODUCTS CO. May 24, 1944, Nos. 10023 and 10024. Convention dates, March 6, 1943, and Jan. 7, 1944. [Class 75 (i)] [Also in Group XXII] In a method and apparatus for flame-machining or de-surfacing ferrous metal bodies using an oxygen stream and a pre-heating flame, the oxygen issues from a nozzle which creates a fringe on the stream of lower velocity than the centre of the stream and fuel gas, e.g., acetylene, is directed transversely into the oxygen stream to mix with the low velocity fringe after emergence from the nozzle to form the pre-heating flame. In one form the nozzle consists of a body 11 having a central oxygen passage 12 of circular section at the supply end 13 but progressively flattened towards the discharge end 18. Passages 19 at each side of the passage 12 conduct acetylene to elliptical recesses 32<1>, Fig. 2, formed between the end surface 20 of the body 11 and a shoulder 31 on the flange 30 of a cap 23 secured to the body at .29 by .bronze welding, silver soldering &c. A recess 37 in the end of the central passage causes eddying of the oxygen stream for production of the low velocity fringe and the acetylene is directed towards it by the recesses 32<1>, the flange 30 having a flat aperture 35 lying outside the orifice 18. Only one passage 19 may be provided on each side of the orifice 18 or acetylene may be fed to one side only of the orifice. The nozzle is secured in a burner head by bevelled shoulders 21, 22 and a notched flange 24. In a modification the orifice 18 and aperture 35 are circular and a concentric series of passages 19 lead to a circular recess 32<1> surrounding the orifice, or the shoulder 31 may be omitted and the flange 30 spaced from the surface 20 by the length of the cap 28. In another modification the flange 30 is supported by transverse ribs 58<1>, Fig. 8, on the end of the body 51, leaving segmental chambers 58 to allow acetylene to proceed from supply passages 53 to inclined passages 59 adjacent the orifice 52. The passages 59'may be of circular section but are preferably of rectangular section to prevent ridging of the work. In further modifications grooves are formed in the end surface of the body to form acetylene passages together with the inner face of the cap flange, these passages having their bases perpendicular to the nozzle axis or inclined thereto, or alternatively the grooves may be formed in the flange. In another modification the nozzle is in one piece and the acetylene passages 82, Fig. 14, lead to oblong recesses 87 at each side of the oxygen orifice. In mounting a row of nozzles in a de-surfacing head H, Fig. 17, the bevelled shoulders 118, 119 are secured against corresponding seats in a body 126 by a screwed sleeve 124 and the body is adjusted to position the end of the nozzle relatively to the head. The acetylene passages 115 lead to inclined channels 130 in the end of the body 111 forming passages together with the thick flange 135 of a cap 132. A cooling water space 142 is formed in the shoe 137 of the head, and leakage of water round the nozzles is prevented by packing rings 139 and springs 140. The shoe is provided with an outer layer of heat and wear resisting alloy having spaced runners 143 to engage the surface of the work W. Oxygen is supplied to the body 126 by a channel 127 and acetylene by a channel 128, the control valves being arranged so that firstly acetylene and oxygen at a pressure of 3 or 4lbs. per square inch is supplied and when the work is raised to ignition tempertature the oxygen pressure is raised to from 30 to 751bs. per square inch and simultaneously the work is traversed past the head. The valves are controlled by solenoids. The pre-heating flame is supplied with excess oxygen so that the reaching of ignition temperature will be indicated by the metal commencing to burn and iron powder &c. may be supplied to the oxygen before, during or after it passes through the nozzles for starting or continuing the reaction when operating on oxidation-resistant bodies.