GB927071A - Improvements in or relating to fluid-conveying apparatus - Google Patents

Abstract

927,071. Making heat exchangers; jointing by forging. ROLLS-ROYCE Ltd. March 2, 1961 [March 11, 1960], No. 8764/60. Classes 83 (2) and 83 (4). A method of forming a fluid-tight joint comprises taking a part having a cylindrical surface provided with a series of axially-spaced channels, taking a tube one of whose two surfaces is for sealing engagement with said cylindrical surface, and the other surface of which has an annulus of metal which forms a local thickening of the tube, locating said cylindrical surface and said tube coaxially and so that said annulus is in radial alignment with at least one of said channels and deforming said annulus by a swaging or like operation radially towards said cylindrical surface so that said one surface is deformed into said channels and the annulus becomes flush with the remainder of said other surface of the tube. In an embodiment the invention is incorporated in a nuclear reactor comprising an aluminium moderator tank 10 through which extend a series of fuel channels 11. The tank is surrounded by a shield 12 and is supported by this shield through lower pivoted links 13 and upper lateral projections 14 slidable in guide channels 15. Surrounding the shield is a housing 16 containing light water. The fuel channels project into outlet and inlet headers 17, 18 for reactor coolants, e.g. super-heated steam. Aluminium tubes 19, Fig. 2, are disposed between the fuel channels 11 and the control of the reactor is effected by varying the level of the light water within the tubes 19. Each fuel channel comprises an inner tube 20 of stainless steel and an outer tube 21 of aluminium. The space 22 between the tubes is supplied with helium. The outer aluminium tube 21 is secured to the tank walls at 10a and 10b, according to the invention. The walls at 10a, 10b are provided with a series of channels 23 and the tube 21 is thickened adjacent these channels so that when a tapered steel sleeve is forced into the end of the tube the thickened portion of the tube is deformed into the channels, Fig. 5. In order to accommodate relative expansion the tube 20 has a necked connector 25 at its lower end attached to a stainless steel tube 26 which projects into the header 18. Another stainless steel tube 27 surrounds the tube 26. The lower ends of the tubes 26, 27 are joined by a vaned spider 28 which serves to admit gas between the tubes from a pipe 29 the gas later passing into the space 22. The outer tube 27 is attached to a chamber 30 connected with the manifold 18 by means of a series of short sleeves 33 to 36, Fig. 3, welded together. The sleeves 34, 35 have a co-efficient of linear expansion between those of sleeves 33 and 36. A similar arrangement is employed at the upper end of the tube 20. The ends of the space 22 are sealed-off by sleeves 44, 45 screwed to the tube 21 or jointed thereto according to the invention. In a modification, Fig. 6, instead of thickening the tube 21 a ring 121 is inserted in the tube and the ring is engaged by the tapered sleeve 24 which expands the ring and the tube to form the joint. When forming a joint between the tube 21 and a sleeve 44, Fig. 7, the ring is fitted externally of the tube and an internally tapered sleeve 124 is forced over the ring.