GB328557A - Improvements relating to heat-exchange tubes - Google Patents

Abstract

328,557. Imray, O. Y., (International Combustion Engineering Corporation). Jan. 24, 1929. Moulds.-In casting extensions on a tube this is preheated to welding temperature and the molten metal is caused to overflow from the mould for some time to heat the tube. A seamless wrought steel tube 11, Fig. 6, is placed in a sand mould, 32, 33 having a recess 34, a broad gate 35, an overflow 39, and strengthener 37, and is heated by a burner 45, Fig. 7, to about 800‹ to 900‹ F. Grev cast iron at 2900‹ F., sufficient to fill four moulds, is then poured in, rapidly at first then slowly, the excess metal flowing out at 39. The mould may be arranged to cast a number of or all the extensions on a tube simultaneously as shown in Fig. 7, the cavities 34 preferably being formed by dividing a long cavity by baked sections 43 or alternate extensions may be cast first and, subsequently, others between them. In another modification the mould consists of hard baked sections 53, Fig. 8, separated by sand coated metal or silicon carbide plates and supported in a box 51 by sand 52. In this case the gate 56 is arranged with its large dimension vertical and the overflow metal passes through a cavity 60 arranged to heat the opposite side of the tube and prevent distortion without adhering.