| 摘要 |
PROBLEM TO BE SOLVED: To prevent formation of a pinhole at a synthetic resin layer in the case of manufacturing a tube joint lined by synthetic resin on an inner periphery of a T-shaped steel tube. SOLUTION: First and second main cores 10, 20 are inserted at a predetermined interval over the entire length of a main tube 51 of a straight tube state into a T-shaped steel tube 50 provided with a branch tube 52 branched perpendicularly to the tube 51, and a branch core 30 is inserted at a predetermined interval over the entire length of the tube 52. A sprue 31 provided at an axial center of the core 30 is in communication within the tube 50 via a pair of gates 33 extended in a circumferential direction of the cores 10, 20. Molten resin flowed out of the gates 33 are fed along a circumferential direction of the cores 10, 20, combined at high pressure at axisymmetrical positions of the cores 10, 20 to prevent air entraining. |
