| 摘要 |
1,005,250. Extruding thermoplastic materials. EASTMAN KODAK CO. March 20, 1962 [March 20, 1961], No. 10578/62. Heading B5A. [Also in Division G3] A method of continuously forming and advancing, at a constant rate, a stream of softened thermoplastics material, comprises the steps of continuously feeding a softened plastics material under pressure into a metering device, discharging the softened plastics material at a metered rate from the metering device, continuously sensing the pre-metering and postmetering pressures of the plastics material and controlling the rate of feed of the softened plastics material into the metering device in accordance with variations in the difference between the raised pressures. Granular or powdered thermoplastic material is fed to a plasticating machine 1, a cylinder 3 and transfer pipe 7 being heated to melt the thermoplastic material, which is conveyed forwardly under pressure by a screw 4 through the pipe 7 to a metering screw 10 and thence to an extrusion device 13, entrained gases and/or volatile material being removed from a take-off on screw 4. The screw 4 is driven by a variable speed motor 6, and the screw 11 by a variable speed motor 11. The pressure in pipes 7 and 17 is measured by devices 8 and 14 which send a signal to a control box 15, which in turn regulate2 the speed of the screw 4 through the variable speed motor 6. The speed of motor 11 is pre-set at a desired value. The control signal may be either electrical or pneumatic. The plastic material which may be used include cellulose acetate, cellulose acetate-butyrate, nylon, polyethylene, polystyrene and polypropylene. |
