PURPOSE: To enable a resin pipe to be easily taken out even if it is larger in length and diameter by a method wherein a core is supported by a circular elastic body put outside an inner cylinder so that the core can be enlarged in diameter and fluid of high pressure and temperature is supplied into a circular space between cores to enlarge the diameter.
CONSTITUTION: The inner cylinder 19 supports the core 20 under a state wherein the elastic body receiving member 25 in the form of a groove is equipped on the sides of compartment plates 22 at both ends of the inner tube 19 and at the outer circumference ends of the ribs 24 at a suitable interval and the circular elastic body 26 is compressed and deformed. When hot and compressed water is poured into the small space 38 between the core 20 and the inner cylinder 19 and circulated, the core 20 and the core for the inserting port undergo an elastic deformation and are enlarged in diameter up to the specified dimension. At this time the core 30 for the receiving port undergoes no elastic deformation. Rotating the core body 11 under that state resin impregnated fiber belt is wrapped spirally and hardened to form a resin pipe. When water of low temperature and pressure is injected, the core 20 is reduced in diameter and peeled from the inner surface of the resin pipe to easily draw up the resin pipe.
YAMAMOTO SHIGERU
NAGAI YOSHIROU
