Patent GB-834205-A (GB)
Title: Method of and apparatus for producing finned tubing
Inventor: STIKELEATHER ROBERT MCINTOSH
IPC: B21C37/26
Filed: 1957-05-18
Abstract: 834,205. Making finned heat-exchanger tubes; reamers. AEROFIN CORPORATION. May 18, 1956, No. 15635/56. Classes 83 (2), 83 (3) and 83 (4). [Also in Group XXIII] Apparatus for the production of finned - tubing comprises tube - straightening means for setting tubing from a coil into the straight condition, means for applying ribbon-like heat-conducting material to the tubing to form helical-finning thereon, and means for feeding the tubing through the straightening means to the fin-applying means. Tubing 15 passes from a coil in a box 16, around a large diameter reel 20, and is fed by co-operating conveyer chains 35 to rotary tubestraightening means 36. The tube-straightener 36 may comprise, Figs. 4, 6, 8, a frame 70, 90, rotated in bearings 86 by a pulley 87 and having journalled therein a cylindrical roll 73, an opposed roll 76 tapered at its ends and two backing-up rolls 94, the rolls being so eccentrically disposed relative to the axis of rotation of the frame 70, 90 that tubing 15 passing through a bell-mouthed guide 96 to said rolls is flexed back and forth and squeezed and hardened as it passes through the rolls to a bellmouthed outlet guide. The tube 15, now straight, is fed by co-operating conveyer chains 37 to storage-troughs 99, Fig. 1. In an alternative tube-straightener, Fig. 13, the cylindrical roll 73 is omitted and the bell-mouthed guides 96 replaced by tapered rolls 101 opposed by cylindrical rolls 102. Straight tubes are drawn from the troughs 99 by a finning machine 300. Rolling; strip feed.-Finning material to be applied to the straight tube is formed from a rod R, Fig. 14, of aluminium or copper by pairs of rolls 211-222 which gradually flatten it to a ribbon 226 of the desired thickness, rolls 217-220 having surfaces as shown in Fig. 15. The ribbon 226 on leaving rolls 219, 220 passes over an idler roll 228 on lever 229, movement of which pneumatically operates a clutch 271 through which the rolls 221, 222 are driven to vary their speed, and on leaving rolls 221, 222, the ribbon 226 passes between thickness control rolls 231, 232. The roll 231 is carried by a lever 2106 carrying at its other end a bleeder rod 2107 movable between bleeder ports in tubing 2111, 2114 connected to a cylinder 2112 which operates means 2116 to vary distance between rolls 221, 222. Strip then passes over an idler roll 234 on a lever 235, then over stretching rolls 236-239, which remove irregularities in the ribbon and whose speed is varied by a clutch 274 pneumatically operated by the lever 235, to slack-take-up and storage-rolls 241, 242 arranged in block and tackle fashion, and thence over further idler rolls to the finning machine 300. A bar 297 on the lower, floating, storage roll actuates switches SW2, SW3 to speed up or slow down the ribbon forming rolls, a switch SW4 stops the forming rolls. Actuation of a switch SW 1. by the bar 297 stops the motor of the finning machine 300. Coiling fins on tube.-A straight tube 15 from a trough 99 is fed through a head 328, Fig. 19, rotated by a shaft 336 driven through variable speed means 338, 339 adjusted by handle 3151, by grooved and roughened rolls 3118, 3119 carried by spring-urged and counterweighted levers in the head 328. The rolls 3118, 3119 are driven through gearing from a shaft 357 driven through variable speed means 354 adjusted by a hand wheel 3141. Rolls 329 in the head 328 grip the tube 15 so that it is rotated with the head. Ribbon 380 to be coiled on the tube is led by guides 382 to pass between a rotated bevel-surfaced roll 331, backed up by a roll 335, and the plane surface of a rotated roll 332, Fig. 34. These rolls deform and stretch the outer edge of the ribbon 380 to curl it on to the rotating and advancing tube 15. Rolls 3155 back up the tube opposite the roll 331. Wave-edged discs 374, Fig. 26, spaced by washers on a shaft 372 and rotated at a higher speed than the tube, then straighten out irregularities in the curled fin ribbon. The disc assembly is swung to or from the tube by a handle 394, Fig. 22. Rubber covered rolls 3156 support the finned tube as it leaves the finning apparatus. -From the finning machine 300 the tube passes to supporting rolls 414, Fig. 35, on tongs T1-T7, Fig. 41, which are actuated by a cam 426 to close in succession as the end of the tube reaches them to move and support the tube. The finned tube is severed from its supply by a saw 435 (Group XXIII). The severed tubing is dropped by the tongs on to two clamps 459 which close to hold the tube. Reamers.-Closing of the clamps operates a valve V12 (not shown), to cause air-cylinders 470, Figs. 35 and 42, to advance frames 471, each carrying a rotating, threaded-tool 475 which enters the tube end to remove internal burrs, and a knife 480 on a member 478 on the tool 475 which removes burrs from the outside of the tube end. The frame 471 also pushes back the fins at the ends of the tubes. A lug 482 adjusts a valve V13 to move the frame 471 back, and a lug 484 opens a valve V14 to open the clamps. Angular bending; coiling; mandrel.-Cut-off length of finned tubing 15f is bent around a rotated form 510, Figs. 44, 45, having spiral troughs 511 conforming to outer edges of the fins. Form 510 bends two or more or less turns or less than one turn, finned tube being clamped at 522 to the form. The tube is supported internally during bending by a mandrel comprising a head section 533 connected by a universal joint to main body 528 secured to a rod 527. The section 533 is threaded externally at 534 and the body 528 at 536 and 537 so that the mandrel may be screwed into the tube. The mandrel is rotated during bending to feed the tube forwardly. As tube is bent it is supported by rolls 540, 544. For bending large diameter tubes the tube is not clamped to the form 510 but is bent therearound by rolls 551, 552, Fig. 46. Specifications 834,206, 834,207, 834,208 and 834,209 are referred to.