METHOD AND MANDREL FOR MANUFACTURE OF PIPES FROM POLYMERIC COMPOSITE MATERIALS Russian patent published in 2002 - IPC

FIELD: pipe and tube production. SUBSTANCE: invention can be used in production of pipes and tubes from polymeric composite materials with inner layer made of elastomer, thermosetting plastic or other material. According to said method when forming pipe body by winding, each double spiral layer of roving in zone of its turning located at end face of formable bell and (or) larger diameter of inner conical surface of pipe is locked against axial displacement by shrinking to side of smaller diameter of inner conical surface of pipe owing to forming by winding a locking joint between pack of double spiral layers of roving band and shaping member of mandrel. To increase efficiency of locking joint in operation, 5-10 ring layers of roving band impregnated with binder are applied over pack of double spiral layers of roving band in zone of formed locking joint. Method s implemented using a mandrel shaping member of which is made in form of cylinder provided with ring projection on its outer surface in form of trapezium in longitudinal section and cut into sectors to form longitudinal cuts in form of angular slots with fixing of each sector by means of fasteners. To provide free demounting of sectors from inner space of wound pipe blank, side surfaces of longitudinal cuts are arranged symmetrically relative to sector split plane forming angle α, exceeding in value central angle β of sector. To enlarge technological capabilities of mandrel, each sector is furnished with strip radially connected with sector, strip being secured on radial rib of mandrel. This prevents displacement of double spiral layers of roving band at shrinking in process of subsequent polymerization of pipe in axial direction towards smaller diameter of inner conical surface of pipe and thus prevents weakening of upsetting of underlying layers of lining and adhesive pack by pack of double spiral layers of roving band. Thanks to it constant pressure built by pack of double spiral layers onto underlying layers of lining and adhesive pack is provided in all cross sections of pipe body in process of polymerization and also high quality of lining over entire length of pipe and reliability of its connection through pack of adhesive layers with pack of double spiral layers of roving band. EFFECT: improved quality of pipes. 5 cl, 4 dwg