| 摘要 |
PURPOSE:To preoduce an outer surface ribbed bent pipe made of a thermoplastic resin excellent in rigidity by subjecting a straight pipe to bending processing without deforming the ribs on the outer surface of the pipe and filling the interior of the pipe with a filler. CONSTITUTION:An outer surface ribbed hard vinyl chloride resin straight pipe 1 (hereinbelow merely referred to as 'straight pipe') is placed on two rotary rollers 31,32 parallelly provided in a water tank 2 at the almost same height and water is poured into the water tank 2 so as to immerse the lower parts of ribs 11 in water and the straight pipe 1 is heated for 5min from the inner and outer surfaces thereof by the infrared heater 41 arranged in the straight pipe 1 and the infrared heater 42 arranged above the straight pipe 1 while the straight pipe 1 is rotated at a speed of 5rpm by rotating the rotary rollers 31, 32. At the point of time when the wall 12 of the pipe is softened, the straight pipe 1 is taken out and fitted in a bent pipe mold having a semicircular cross section while the softened pipe is bent and cooled as it is by sprinkling water over the pipe and the cooled pipe is taken out of the mold to obtain an outer surface ribbed hard vinyl chloride resin bent pipe. |
