| 摘要 |
<p>1,201,069. Blow-moulding and sealing; seaming non-metallic sheet material. DOW CHEMICAL CO. 25 Sept., 1967 [26 Sept., 1966], No. 43486/67. Headings B5A and B5K. [Also in Division B8] A plastics container is fornied, filled, and sealed by means of apparatus which extrudes a parison 66 in sterile condition, closes its lower end, injects pressurized fluid into the parison to expand it against mould halves 68, fills the container thus formed with a sterile product, e.g. sterilized milk, and seals the container by means of a sealing bar 70 while its plastics material is still hot. Moulding and sealing.-To extrude the parison 66, polymeric resin is supplied by a screw 54 to a cylinder 56 in which a measured quantity is accumulated before being driven by a piston 58 through a die orifice 64. The die halves 68 and halves of an ejector 112 are then closed, the parison being sealed at its lower end by jaws 96, while the parison remains hot. The parison is blown by air supplied through a mandrel 78, and its upper part is formed round the tip of a sealing bar 70 housed within a die head 84, so that protrusions 110 are provided. This formation prevents undue stretching of the plastics material when the bar 70 is advanced to form a seal. Ports 103 in the die head 84 allow heated fluid to pass through it and so keep the parison in condition for sealing. Reciprocable slides (90), Fig. 4 (not shown), co-operate with the bar 70 in forming the plastics material in the sealing area and are withdrawn before the bar 70 advances. Ports 103 may also be used for a cooling medium in the same way as ports 105 in the mould halves 68. After the die halves 68 are opened the filled container is ejected by the members 112. Filling.-Either simultaneously with, or after the blowing of the parison a filling tube 46 is lowered into the container mouth and a quantity of liquid, e.g. sterilized milk, is supplied from a measuring tank 30. The container, which is sterile due to the high temperature of the plastics material, is sealed by the bar 70 when the tube 46 is raised. Liquid supply.-A supply tank 16 is sterilized by steam controlled by a valve 20, the steam being displaced by air from an inlet 22 passing through a filter 24. Milk is supplied through a valve 26. A feed pipe 28 to the measuring tank 30 is controlled by a valve 32 closed by electrical means when the milk level in the tank 30 reaches an indicator 34. The tank 30 is sterilized by steam controlled by a valve 40, the steam being displaced by air from an inlet 36 paasing through a filter 24.</p> |
