END STRUCTURE FOR THERMOPLASTIC TUBING

1303329 Pipe couplings E I DU PONT DE NEMOURS & CO 22 April 1970 [23 April 1969] 19321/70 Heading F2G A bundle of flexible thermoplastic tubes 21 or a single flexible thermoplastic tube (30), Fig. 3 (not shown), is provided with an end fitting which allows a radially deformable hose 22 to be clamped around the bundle or single tube in a fluid tight manner without collapsing the tube or tubes. According to the invention the fitting comprises a thermoplastic sleeve 11 having a first portion 12 formed with a circumferential groove 33 into which part of the hose can be deformed by at least one band clamp 19, 20, a second portion 13 of lesser diameter than the first portion and to the internal surface of which the bundle or single tube is bonded, and a rigid collar 15, e.g. of stainless steel, located within the first portion 12 to withstand the clamping pressure. Annular shoulders 18, 44, having axial extents large enough to prevent deformation by, for example, cold flow under varying pressure conditions, provide abrupt, highly discontinuous ends to groove 33. The axial extent of collar 15 may be less than that of groove 33 so that clamp 20 deforms the sleeve 11 inwardly which prevents shifting to the right of the collar. A third portion 17 of the sleeve may be slipped over the threaded end of a tubular heat exchanger, Fig. 4 (not shown), and secured by further clamps.