GB1390614A - Extrusion - Google Patents

Abstract

1390614 Cooling extrudate IMPERIAL CHEMICAL INDUSTRIES Ltd 10 April 1972 [14 April 1971 22 Feb 1972] 9350/71 and 8108/72 Heading B5A [Also in Division F4] A thermoplastics extrudate 2, Figs. 1, 3, is cooled by passing it down an inclined trough 4 down which water 3 or other cooling liquid flows at a higher speed than that at which the extrudate emerges from die 8, and the extrudate is drawn away from the trough at the same speed or slower than the water flow. The thermoplastics material (examples given) is supplied by a screw extruder 1 or through a valve from the base of an autoclave 70 (Fig. 6, not shown) to a multi-orifice die 8 to emerge as strands 2. Each strand passes down a separate V-section or flat-bottomed channel of the trough 4 and across a gap into channels 12 from where it is drawn by a Venturi 16 through tubes 18 to cutter 21. Air is supplied to the Venturis and suction applied to the tubes 18 to remove water. Water 3 from the end of the trough 4 and from the strands runs back down channels 12 to a drain 14. The Venturi tubes may be replaced by a single-slit Venturi connected directly to the trough 86 (Fig. 7, not shown) and operated by water to increase cooling. In Fig. 4 cooled water from tank 21 pours over a weir and down an inclined trough 12 where strands 18 are extruded downwardly and deflected along the trough by a water curtain (not shown) at C. The strands 18 are carried by a perforated conveyer 14 to a cutter 16 while the water falls through the conveyer on to tray 43 or into tank 42 for recirculation. The cutter may be positioned between the trough 12 and the conveyer 14.