| 摘要 |
1,199,536. Making tubular films. ETHYLENE-PLASTIQUE S.A. 11 Oct., 1968 [13 Oct., 1967; 1 Oct., 1968], No. 48415/68. Heading B5B. A device for cooling a tubular film or tubing of a synthetic organic thermoplastic polymeric material immediately after it has left the die through which it has been melt-extruded comprises a flexible slightly resilient porous stationary sleeve or tubular element consisting of a hydrophilic fabric supported only at its ends and which is located immediately downstream of the extrusion die and coaxial therewith and means for applying a cooling liquid to the flexible sleeve or tubular element. A similar sleeve coaxial with the first sleeve may be located downstream thereof in such a manner that any cooling liquid dripping from the first sleeve does not wet the second sleeve, means being provided for supplying a stream of a drying gas to the outer surface of the second sleeve. As shown in the drawing, a tubular film is melt extruded from the annular die of an extrusion head 10 and is cooled by passing through the sleeve 6 in contact with its inner surface. The sleeve may consist of a woven, non-woven or knitted fabric formed of hydrophilic fibres and water or other liquid coolant is supplied at a uniform rate to the outer surface of the sleeve and permeates it to form a thin film of liquid coolant in its inner surface. The space between the tubular film, the face of the extrusion head 10 and the sleeve 6 is either open to the atmosphere or connected by a pipe 11 to a pressure-regulating device. The two ends of the sleeve 6 are held in position by two rigid rings 1 and 2 which expand it slightly and between which it is stretched longitudinally. The upper part of the sleeve is surrounded by and in contact with a thick porous strip 4 of a hydrophilic material such as cotton felt on to which water is sprayed under pressure by a series of nozzles disposed at regular intervals along the inside of an annular manifold 5 coaxial with the extrusion axis. The lower ring 2 is attached to a tray 2 for receiving the liquid coolant flowing down the sleeve 6. A second similar sleeve 7 is disposed between rings 2 and 3 and currents of warm, dry air supplied to an annular chamber 9 surrounding the sleeve impinge on the sleeve and evaporate the water which has been wiped off the tubular film by the sleeve. |
