| 摘要 |
1,182,295. Jointing by tube expanding; welding by pressure. FOSTER WHEELER CORP. 2 March, 1967 [6 June, 1966], No. 10035/67. Headings B3J and B3R. [Also in Division F3] A method of expanding a tube 14 in a tube sheet 16 comprises using a central explosive distributed axially along the tube, and transmitting the explosive force through a tubular member 24 of polyethylene or other resin (list includes "Nylon" and "Teflon," (Registered Trade Mark) having the same flexibility, formability, resilience, density and at least as high a melting- point as polyethylene. The end 18 of the tube may be welded or brazed to the tube plate, and if Á-tubes are expanded, compressed-air in the tubes forces the inserts 24 from the tube-ends. The sheet 16 may be of carbon steel or clad with nickel alloy or stainless-steel and the tubes can be carbon steel, stainless-steel or an alloy such as copper-nickel. Grooves may be formed in the tube-sheet for keying with the tubes, and the explosive charge concentration may be as low as four grains per foot. The force-transmitting tube may be extruded about an explosive core 26 of Primacord. In Fig. 1, two layers 28, 30 of force-transmitting polyethylene &c. are used and an air-gap 34, closed by an end cap 36, to reduce the expansion at the end of the tube. In addition, a lesser charge concentration of four grains per foot may be used in the air gap, or a uniform concentration of 25 grains per foot may be used over the length of the core 26. A paper covering may be placed over the layer 30 to avoid depositing any plastics material in the tube. A modified explosive insert includes a single plastics force-transmitting sleeve (40), Fig. 2 (not shown), on an explosive sleeve (42) which surrounds the explosive core (44). The explosive sleeve may be replaced by a cluster of outer cores (46), Fig. 4 (not shown). |
