| 摘要 |
1306979 Extruding thermoplastic material H HENCH 6 Aug 1970 [6 Aug 1969 15 June 1970 (4)] 37927/70 Heading B5A Apparatus for the granulation of plastics material comprises a melting vessel 2, Fig. 1, from which molten plastics is fed to an extruder 3, Fig. 3, comprising a number of radial ducts 14 each leading via a valve 15 to an extrusion nozzle 16 emitting a molten plastics strand. The nozzles are arranged in a circle and the strands therefrom are received by a correspondingly located circular series of fluid coolant ducts 50, Figs. 6 and 7, located in a vertically adjustable unit 4 supported by a wheeled carriage 7. The upper end of each duct is surrounded by a tubular casing 51 and is associated with a removable injector head 52. Coolant water is supplied to a headwater chamber 44 of the unit 4 and passes via a filter 46 into the heads 52 containing radial guide fins 58. Water under pressure is fed to an annular chamber 47 and flows upwardly through a filter 48 to an annular space 59 surrounding each duct into its injector head where the flow is reversed to create a suction effect around the strand. Each strand passes from a duct 50 through an attached pipe 10 to a cutting unit 5, Fig. 9, comprising a housing 69 receiving the ends of the pipes and the discharge of coolant therefrom. A shear bushing 73 is positioned at the outlet of each strand into the housing 69 and co-operates with a vertically adjustable rotary cutter comprising a circular series of detachable cutters 74 located on the periphery of a circular rotor 76 driven via a shaft 79, drive gear 8 and motor 9, Fig. 1. The extrusion nozzles may be located in two or more concentric circles, in which case instead of a single rotary cutter a number of rotary cutters may be located on a circle, each co-operating with a group of shear bushings. A heating medium surrounds the ducts 14 and the valves controlling the flow therethrough may be operated simultaneously by means of a valve control ring 22, Fig. 3, carrying rollers, Fig. 8, (not shown), engaging valve control levers 18. The rotational position of the ring is controlled pneumatically or manually. In a modification a cylindrical filter is located between each valve and the nozzles which it feeds, means being provided to allow heating medium to flow around the valves and the filters which are removable. |
