GB524922A - Improvements in the manufacture of tube - Google Patents

Abstract

524,922. Making compound pipes. ARMSTRONG, J. J. V. (American Rolling Mill Co.). Nov. 10, 1938, No. 32643. [Classes 83 (ii) and 83 (iv)] [Also in Group XL] Soldering.- Relates to apparatus for making tubing from strip metal stock in which portions of the strip are bent to tubular form and then united by molten sealing metal as they pass through a heating zone, and consists in maintaining heat uniformly over a given length of tubing in a zone and directing light from the tubing, within said length, upon a photo-electric cell in a relay circuit adapted to stop the feed of the tubing through said zone and the heat supply thereto if the temperature of the tubing lies above or below a predetermined range of temperature. The machine shown in Fig. 1 is designed to make a tube of the kind shown in Fig. 4 comprising an inner ply 1 with a butt seam and an outer ply 2 with a scarfed seam. The strip 1 for the inner ply is made into a tube by rollers 3, while the strip 2 for the outer ply has its edges bevelled by rollers 4. The strip 2 is then made into a tube around the tube from the strip 1 by rollers 5, after which the twoply tube passes between three sets of rollers 10, 11, 12. The middle set 11 is connected to a bus-bar 15, and the outer sets to a bus-bar 13 ; and these bus-bars are connected to the secondary of a transformer 14, the primary of which can be connected to a power supply by a switch 60 controlled by a solenoid 61. During the passage of the two-ply tube from rollers 10 to rollers 12 the tube is heated by the electric current which causes a coating of soft or hard solder at the joints to melt. On leaving the rollers 12, the tube is passed by rollers 25 to a cooler 26 where the joints harden. The heating can be regulated by adjusting the rollers 10 in relation to the rollers 11 by means of a handle 23 operating a gear 22 on a screw 20 mounted on a frame 16, and adjusting the relation of the rollers 10 and 11 together in relation to the rollers 12 by a handle 24 operating the screw 20 which besides engaging the gear 22 also engages a lug 21 on the housing of the rollers 11. The tube is enclosed by a series of tubular housings 29, 28, 27, and 27a; and when a jointing material such as copper is used, a reducing or neutral gas is introduced into the housings by a pipe 29a.