GB548686A - Improvements in and relating to the manufacture of heat exchangers - Google Patents

Abstract

548,686. Making heat exchangers. ASCOT GAS WATER HEATERS, Ltd., and FRIEDMAN, L. Aug. 28, 1941, No. 10983. [Classes 83 (ii) and 83 (iv)] Angular bending; coiling soldering.-A coiled liquid conveying tube is applied to a shell to form part of a heat exchanger such as a gas water-heater by means of a grooved roller, one end of the tube being held on the shell and the shell and roller rotated in opposite directions without any relative longitudinal movement. The tube 21 which may be bent to U-shape so as to form a double coil is secured by a clip 22 to one end of a shaft 9 carried by an expanding mandrel 8 which may be operated by fluid pressure and provided with a dash pot for ensuring slow expansion movement. The mandrel, which is rotated by chain gear from an electric motor, is geared to a roller 6 provided with grooves 19 of constant or variable pitch. The free ends of the roller mandrel spindles are connected by a handled yoke 13. The legs of the tube pass into the grooves of the roller being guided thereto by channel guides 29 on sleeves 30 slidably mounted on bars 23 and shoes 28 on levers 27 pivoted on the bars 23. The bars 23 depend from a block which is urged by springs in the direction of travel of the tube along the shell as coiling proceeds. The levers 27 pass between lugs 27a on the sleeves and may be pushed down so as to raise the shoes 28 to release the tube. Solder strips 31 may be passed from a supply drum over rollers 32 on the bars 23 and through funnel guides 32a carried by the guides 29 so as to pass between the tube and shell. Towards the finish of the coiling operation the strips are cut by hand operated shears 36, 37 mounted on a box 34. This box also carries a grooved guide 40 for receiving the ends of the tube which are bent by hand so that they can lie in the grooves 41 of the roller. This bending is effected between the rollers 43 on a handoperated lever the pivot of the outer roller being placed in one of the holes 44 in the box. This end of the coil may then be secured by a clip to the shell. Prior to effecting the bending operation the machine is automatically stopped by trip pins 50 on a plate 49 geared to the roller shaft, the pins operating trip switches in the motor circuit. When the machine is stopped a member 45 is at the same time automatically moved, e.g. by fluid pressure, into position to support the mandrel during bending. After coiling, the mandrel is collapsed and the article removed therefrom and placed in an oven to effect the soldering. The mandrel may be longitudinally grooved to receive a seam on the shell.