| 摘要 |
324,648. Hampel, H. Aug. 28, 1928. Apparatus for making films.-Films or strips are prepared from solutions of cellulose or its derivatives by forcing the solution in accurately measured quantity by means of two rotary interengaged toothed rollers mounted in a casing which closely embraces them, through a slit like moulding die accurately adjusted to determine the thickness of the extruded material and allowing the extruded sheets to pass directly on to a travelling bed. The thickness of the extruded sheet may be controlled by adjusting the speed of the travelling bed in relation to that at which the plastic mass issues from the moulding slit. In the apparatus shown in Fig. 1, the solution of the material to be moulded is fed from a pipe 11 into a hood 10 fitted with a pipe 12 for the evacuation of air and is then forced by means of the rollers 2, 3, which rotate in opposite directions and are closely embraced by the casing 1, through the moulding slit 5 onto the surface of a rotating drum 15. The rollers may be driven through a pulley mounted on one of the shafts 13, 14. The moulding slit 5 has substantially same length as the feed rollers and preferably takes the form, Fig. 2, of a flat duct, the inner wall surfaces of which are absolutely smooth and parallel, but the lower edges of the slit may be rounded off. The slit is formed between a fixed plate 6 and an adjustable plate 7, small spacing plates 9, 10, being provided to ensure parallel adjustment. |
