JPH05309729

PURPOSE:To provide a method for extracting certainly effectively air in a tube on a sending out side when the tube is pressure expansion molded by a pressure system and an apparatus therefor. CONSTITUTION:The figure shows as follows; a tube 7 sent out for expansion molding is heated in a heating bath 3; thereafter, it goes through an air stop for flattening by pressurizing once radially with a pressure roll 4; it passes through a pipe 5 for expansion molding; and the tube is expansion molded by applying inner pressure thereto by sending pressure air from a progressive direction side of the tube. Then a plurality of rolls 13 are brought into contact with the tube while keeping a specific gap along a running direction of each tube from both sides of the tube on a sending out side from a position of the air stop, and moved along an endless track in a reverse direction to the progressive direction of the tube. Thereby, air in the tube on the sending out side from the air stop is extracted.