Abstract: Connection of membrane support tube supporting a filtration membrane and another tube path, both being provided with conical recesses and a double conically shaped sealing ring sealingly engaging the conical recesses, while a sleeve integral with the ring sealingly engages the membrane. The end faces of the support tube and the other tube part are free from sealing engagement with sealing material.

Abstract: A device for manufacturing a plastic tube with transverse or helical grooves consisting of an extruder, two movable halves of die with an inner ribbed profile and being capable of forming a hollow mould, said halves of die each provided with circular elongations for heating the region between the opening of the extruder and the beginning of the mould, an inflatable member in the tube for conforming the tube to the profile of the mould. The inflatable member comprises a movable cylinder having two expandable end discs, an inlet and an outlet for compressed medium being situated between the two end discs, the valve closing said outlet being loaded by a spring such that only pressure medium will escape after the end discs have formed a closed space with the inner side of the tube.