Patent GB-756108-A (GB)
Title: Improvements in expansion joint and method of making same
IPC: F16L51/02
Filed: 1954-07-27
Abstract: 756,108. Making bellows for pipe couplings. ZALLEA, J. P. July 27, 1954, No. 21922/54. Classes 83 (2) and 83 (4). [Also in Group XXVIII] Stamping-A process of forming from a round tubular blank a flexible pipe coupling or bellows element comprises confining axially spaced portions of the blank with annular members roundedon the circumferential edges thereof which face each other, bulging the unconfined portions of the blank by subjecting the blank interior to fluid pressure, moving said spaced portions axially towards one another to aid the bulging process said movement being sufficient to provide the bulge with an outer part in the form of a major segment of a circle and a pair of inner parts reversely curved relative to said outer part, said inner parts joining the outer part to the spaced portions, means being provided for reducing the amount of the pressure medium as the capacity of the blank changes due to the axial movement of the spaced portions. The tubular blank is placed between upper and lower platens 11 and 12 respectively of a hydraulic press. The platens carry conduit nipples 14 and 24 each supporting an annular member 18 and 21 respectively arranged within the ends of the blank. The nipples communicate with conduits 17, 26 through which pressure fluid may be supplied to or released from the interior of the blank. The annular members are recessed to provide seatings for rubber sealing rings 20, 23 which are compressed to provide fluid-tight seals between the blank and platens. Die rings 27, 28 are bolted to the upper and lower platens respectively and have rounded edges 32 and 33. In operation, fluid pressure enters the blank from the conduit 26 and, after venting, the conduit 17 is closed by a valve (not shown). The pressure compresses the sealing rings and when the blank begins to bulge the movable platen 12 is raised until the required corrugation is obtained. The pressure fluid is vented through conduit 17 as the internal capacity of the blank is reduced. The corrugated blank or bellows element has pipe nipples 39, 40 (Fig. 4) welded or brazed to the tubular sections 29, 30 of the element respectively to enable the element to be welded onto a pipe line. In an embodiment flanges may be provided on the nipples to enable them to be bolted to corresponding flanges on the pipe line (Fig. 5) and the tubular sections 29, 30 of the element are bent around and welded to the flanges. A plurality of bellows elements may be connected together by a series of interconnecting sleeves 52 to form a multiple bellows expansion joint as shown in Fig. 6. Alternatively, the bellows element shown in Fig. 4 may be formed by welding the pipe nipples 39 and 40 to each end of the cylindrical blank and then placing the blank in the press as shown in Fig. 3. In this embodiment the pipe nipples act as the die rings. In a further embodiment a bellows element having a pair of axially spaced corrugations (Fig. 8) may be formed by welding a centrally located sleeve member 60 to the cylinrdical blank and then placing the blank in a press as hitherto. By increasing the number of sleeve members a bellows element having a plurality of corrugations may be formed.