Patent GB-957720-A (GB)
Title: Improvements in or relating to releasable fluid-tight joints
IPC: F16J13/02
Filed: 1960-06-23
Abstract: 957,720. Joint-making packing; pipe joints; covers for resisting fluid pressure. SIEMENSSCHUCKERTWERKE A.G. June 23, 1960 [June 23, 1959], No. 22084/60. Headings F2B, F2G and F2P. [Also In Division B3] In a releasable fluid tight joint comprising first and second joint parts each having a sealing portion that co-operates with the sealing portion of the other joint part and a connecting portion which is spaced from the sealing portion and engages with the connecting portion of the other joint part, the joint is sealed after its assembly by relative thermal expansion of the said joint parts. The relative thermal expansion may be obtained by heating or cooling one of the parts before connecting them together and/or, in the case of joints operating at elevated or reduced temperatures, by the use of materials having differing coefficients of thermal expansion. In the embodiment shown in Fig. 1, a container wall 1 is preheated by heating coils 12 and a closure member 2 is screwed into the container to make contact therewith at 3. Subsequent cooling of the container causes tight sealing contact between the parts at 3, which sealing pressure may be increased at elevated operating temperatures if the material of the member 2 has a greater coefficient of thermal expansion than that of the container. The closure member 2 may be removed by cooling it, for example, by means of coils 11. A sealing ring may be placed between the sealing surfaces at 3 and the member 2 instead of being screwed in the container may be held in position by a retaining ring screwed in the container. In a modification the sealing surfaces are cylindrical and the wall 1 shrinks radially on cooling to engage the member 2. In Fig. 4, a member 1 secured to a member 2 is held in sealing contact at 3 or 3<SP>1</SP> with surfaces of a container 5 by a sleeve 7 which is screwed on the member 2 and abuts a looking ring 4. The member 2 has a greater coefficient of thermal expansion than the member 1 whereby at elevated operating temperatures the sealing pressure at 3 or 3<SP>1</SP> is increased. If sealing is to be effected before the container is filled with operating fluid, a heating medium is passed through passages 10, 11 until the desired operating temperature is reached. When like materials are used for the members 1 and 2, and the container is not intended for use at elevated temperatures, the member 1 may be expanded by supplying heating medium through passages 10 and 11 before assembling it in the container so that after assembly sealing occurs on cooling to operating temperatures. In Fig. 5, a sealing ring 3 is interposed between the members 1 and 2 and is pressed radially against the container 5. If the parts are of like material, the member 1<SP>1</SP> is cooled before assembly so that after assembly it expands to produce a radial sealing pressure on the ring 3. To release the joint the member 2 is heated. The sealing ring may be in the form of a spring ring 8, Fig. 12, which may be separate from the parts to be sealed or welded to one of them. In the construction of Fig. 12, the member 2a is slidable in a sleeve 14 screwed to a locking ring 4, the sealing ring 8 is mounted between the member 2a and the ring 4 and a pressure limiting spring 15 bears on the ring 4. In assembling the joint, a nut 6 is screwed on the preheated member 2a to provide an initial sealing pressure on the ring 8 and subsequent contraction of the member 2a by cooling will increase the sealing pressure to a limit determined by the spring 15.