Patent GB-547112-A (GB)
Title: Improvements in pressure butt-welding of hollow metal members
IPC: B23K5/00
Filed: 1941-06-27
Abstract: 547,112. Annealing. LINDE AIR PRODUCTS CO. June 27, 1941, No. 8080. Convention date. Aug. 3, 1940. [Class 72] [Also in Groups XXII and XI] In butt welding hollow members of the same or different diameter or thickness, the parts have their surfaces pressed together and are then concurrently heated on their outer and inner peripheries adjacent and at each side of the interface by heat applied directly to the exposed surfaces, whereby the abutting surfaces are heated to welding temperature and welded under pressure by heat conducted through the members to the surfaces. Pipes P', P to be butt welded are secured in chucks respectively in fixed and movable heads F, H. Each head is provided with chucks at each end to facilitate alignment of the pipes. The slidable chuck jaws 20, 21<SP>1</SP> are wedge shaped and grooved and are operated respectively by pairs of hydraulic cylinders 30, 30<SP>1</SP>, 31<SP>1</SP>, 37, and 37', 38' controlled by a valve from a handle 200. The welding pressure is applied to the slidable head H by a pair of hydraulic cylinders 39, 40 through rods 43, 44 as controlled by a valve operated by a handle 205. The outer and inner torch heads T, T' are preferably provided with a pair of staggered rows of nozzles 81 and are mounted so that during welding and subsequent annealing they can be reciprocated across the joint and also rotated or oscillated round the pipes. The head T consists of a pair of semiannular members 69, 70 connected to blowpipes 72 and provided with water cooling connections 74, 75. These members are carried by arms 76, 77 which are pivoted at 78 in blocks 79 adjustable by a screw 83 in a torch carriage 67, which may be oscillated on an arcuate guide 65 fixed to a bracket 58 on a plate 57 mounted on a slide 50. The plate 57 is reciprocated by an hydraulic cylinder 59 as controlled through adjustable stops 61 by a pilot valve 64 operating a reversing valve to which the supply is controlled by a valve operating by handle 224. The stops 61 control the length and location of the path of reciprocation of the plate 57. The slide 50 is adjustable by rack and pinion 55, 54. In welding parts of different thickness the thicker part only is heated until it reaches dull red heat, whereupon the centre of reciprocation is shifted so that both parts are heated equally. As the parts are upset the centre of reciprocation is gradually altered to correspond. The members 69, 70 may be opened by links 90 through an hydraulic cylinder 88 controlled by a handle 212. The carriage 67 is provided with a curved rack 109 and is oscillated on the guide 65 by a pinion 108 driven by sprocket gear 107 from a shaft 92 oscillated by a pinion 93 and rack 97 which is reciprocated by an hydraulic cylinder 96. The adjustable stops 100 on a rod 99 carried by the rack operate an arm 103 of a pilot valve 102, which is connected to a reversing valve supplied with pressure through a valve controlled by a handle 239. Adjustably mounted on the plate 57 is a bracket 169, Fig. 11, supporting on a rod 168 a pair of hollow half rings 166, 167 through which circulates air, water &c. to cool the thinner part so as to limit the extent of the heating zone in the event of welding together parts of different thickness. The half rings are applied to the work by hydraulic cylinders 177. 178 through springs 180. the supply being controlled by a valve operated by a handle 218. The inner torch head T' is connected by a casing 113 to a block B<SP>11</SP>, the casing passing through a tubular member 149, Fig. 10, mounted in a pedestal 148 in a plate 143 adjustable by a screw 160 on a platform 138 provided with a pedestal bearing 140 for the shaft 92. The shaft 92 is provided with a pinion 142 and a collar so that the platform reciprocates with the shaft 92 and plate 57. The member 149, which is oscillated by spur gear 142, 146 and sprocket gear 153 from the shaft 92, has a head 150 provided with a series of recesses 151 in which may engage fingers 156 on a split collar 154 adjustably clamped on the casing 113. The collar is locked to the member 149 by a spring-pressed lever 157. The nozzles 117, Fig. 12, in the torch head T<SP>1</SP> communicate by a passage G and passages 124 with the mixing chamber of a blowpipe 125, while cooling fluid is circulated from passage 127 through passages W, 115, 122, W<SP>1</SP> and 128. Air may be supplied through port 123 and passage A<SP>11</SP> to an angular manifold 121A so as to protect the assembly. from hot combustion gases or the tube 120 may pass through the apertures in the cap 114 and have secured thereto a cap with spaced lateral outlets. The casing carries a collar 129 mounted on ball bearings in a member 133 provided with radial rollers 135 in contact with the pipes. The pipes may be further supported on rollers 165 carried by vertically adjustable members 164. The head F is provided with a bracket 182 carrying a rod 183 which operates a switch 186 on an adjustable bracket 185 so as to operate solenoid controlled cut-off valves to cut off supply of gases to the torches when the work has been upset a predetermined amount. In a modified apparatus, the workparts may be oscillated or rotated instead of the torch assemblies. In this case the chucks 20<SP>1</SP>, 20 are carried respectively by the body 262 and by the body 264 keyed thereto and rotating in collar bearings 267 and radial thrust bearings 268 and the adjusting rings 271, 275 are keyed at 272 thereto and flanged to engage the split pressure rings 274, 277. The chucks in the head F are rotated by an electric motor through a pinion and ring gear. The ring gear mates also with a pinion keyed to a shaft in two parts connected by a splined coupling, one part having a pinion meshing with a ring gear 285 keyed to the chuck body of the movable head H. The outer torch sections have arms pivoted on a pin secured to the torch bracket, the other ends of the arms being connected by links to the piston rod of cylinder 88. Reciprocation of the inner torch is effected by connecting the outer torch bracket by a rod with a bracket on the plate 138. The joint may be annealed after welding at temperatures around 900‹C. while reciprocating the torches across the joint about twice the distance employed during welding. Specification 532,422 is referred to. The Specification as open to inspection under Sect. 91 states that the process may be applied to welding plates or bars. This subject-matter does not appear in the Specification as accepted.