MANUFACTURE OF LAVER SCREEN MADE OF SYNTHETIC RESIN

摘要

PURPOSE:To obtain a laver screen made of woven plastic tubes, having decreased ratio of the area contacting with the laver to the whole area of the laver-supporting face, by forming a cavity having smaller dimension than the diameter of the plastic tube to the laver-supporting face of the screen. CONSTITUTION:Pipes 1 having a diameter of about 1.5-2.5mm. and manufactured by extruding a thermoplastic resin such as polyolefin resin, polystyrene resin, etc. are woven with natural or synthetic fiber yarns to obtain a laver screen. The horn 4 of the ultrasonic machining tool is pressed to the laver-supporting face of the screen to form a saddle-like or groove cavity 3 having smaller dimension than the diameter of the tube 1 and extended along the direction crossing the axis of the tube 1. The variation of the adhesivity of the laver to the convex part neighboring to the concave part can be decreased, and the manufacture of the screen and the operation of the laver-culturing work can be carried out with high reproducibility.