| 摘要 |
PROBLEM TO BE SOLVED: To improve the cooling efficiency and the extrusion rate and further enable the continuous production to be performed by forming a helical groove through which a cooling liquid is made to pass, in the inner wall face of a forming tube. SOLUTION: A helical groove 11 for the passage of a cooling liquid is, for example, formed in the inner wall face of a forming tube 1. Further the forming tube 1 makes the cooling liquid pass in an arrow direction when a resin pipe 2 extruded from an extrusion machine is allowed to pass, so that the cooling liquid comes into contact with the resin pipe 2 directly. Thus the forming tube 1 is used in such a state that the cooling efficiency is increased. Consequently the cooling efficiency is enhanced to be able to increase the extrusion rate. Alternately a groove for the passage of a solvent is formed across the peripheral direction of the inner wall face of the forming tube 1. A bleedout is dissolved by flowing the solvent through the groove and therefore, no deposit is accumulated on the inner wall face of the forming tube 1. For the described reason, the continuous production of the extrusion-molded resin pipe 2 is realized as the molding operation need not be suspended each time for cleaning. |
