HEAT-SHRINKABLE SHEET HEATING DEVICE

摘要

PURPOSE:To heat automatically and uniformly a pipe extending over the whole circumference by making use of a heat source whose safety is high by differing from a flame of a burner, by a method wherein a hot air ring outserted over a coated steel pipe is moved in the direction of a pipe axis by a self-propelled traverse rest, which is made into a heating method of a heat-shrinkable sheet. CONSTITUTION:A rest 1 is mounted on a coated steel pipe W by turning a heat-shrinkable sheet 5 inside under a state where a lower semicircular pipe 3-2 and flexible tube 4-2 are removed from a hot air ring 3. Then the lower semicircular pipe 3-2 of the hot air ring 3 is fitted into the coated steel pipe from the lower side and connected with an upper semicircular pipe 3-1 through a clamp lever with which a flexible tube 4-2 is connected further. Then the hot air ring 3 is moved to the central part (weld bead part) of the heat- shrinkable sheet 5, hot air having a predetermined temperature is sent into the hot air ring 3 through the flexible tube 4-2 and the central part of the heat-shrinkable tube 4-2 is heated and contracted, to begin with. Then the heat- shrinkable sheet 5 is heated and shrinked in order while moving the hot air ring 3 at a fixed speed toward a one side end part from the central part by driving a linear motor 2-3.