| 摘要 |
PURPOSE:To form the plastic pipe, high in roundness and prominent in dimensional stability, without receiving external injury or deformation by a method wherein a plurality of metallic packings, having U-grooves, are arranged in the seal case of a dimension control mechanism so that the U-grooves are faced to opposite directions mutually. CONSTITUTION:The device is constituted of an extruder 1, the dimension control mechanism 2, cooling mechanism 3 and a winder 4. A plurality of metallic packings, having U-grooves, are arranged in the seal case of the dimension control mechanism 2 so that the U-grooves thereof are faced to opposite directions mutually while the plurality of metallic packings are fixed by a cap and a packing gland. Control of dimension is effected so as to secure the finishing dimension and roundness of the pipe under expanding the plastic pipe 16 by evacuating the inside of a sizing dice 11 and a cooling water tank under sucking by a vacuum pump from the upper side of the cooling water tank 12. |
