JPS6434513A - Manufacture of wear resistant bent duplex pipe - Google Patents

Abstract

PURPOSE:To improve productivity of a duplex pipe and to prevent the breaking of an inner pipe by bonding a number of wear resistant material pieces on the surface of a bend keeping pipe to form the inner pipe, then by joining the bent outer pipe and the lining inner pipe. CONSTITUTION:A number of the wear resistant material pieces 4 are previously bonded on the curved surface of the bend keeping pipe 3 and disposed. At this time, the outer diameter of the pipe 3 on the outer surface of the pieces 4 is nearly in accord with the inner diameter of the bent outer pipe. Then, the lining inner pipe 2 bonding the pieces 4 is inserted into the bent outer pipe 1, and while the pipes 1, 2 are moved relatively, the pipe 1 diameter is reduced and the lining inner pipe 2 is compressed through a heating system 6 and cooling water injecting means 7, 7 disposed on the outer periphery of the pipe 1. The micro-elastic deformation of the pipe 3 eases an excessive compressive stress of the pieces 4. Because the pipes 1, 2 are jointed with a proper strength by this method, the productivity of the duplex pipe is improved and the breaking of the inner pipe 2 is prevented.