GB1495781A - Method of and apparatus for making blown thermoplastic articles - Google Patents

Abstract

1495781 Temperature conditioning parisons for blow moulding OWENS-ILLINOIS Inc 21 Jan 1975 2487/75 Heading B5A Prior to blow moulding a parison it is placed in a conditioning chamber 50 or 75 and heat transfer fluid is passed between it and the walls of the chamber to heat or cool the parison to the best temperature for biaxial orientation during blowing. A parison 11 (Fig. 1, not shown) is formed in an injection mould (15) and is withdrawn on a core 22 and transferred to a conditioning station, Fig. 2, where the halves 51, 52 of the conditioning chamber close about it. Heat transfer fluid is passed through passages 37-39 in the core and through passages 42, 43 into the chamber where fins 54 cause it to spiral around the parison before discharging through passage 55. The conditioned parison is transferred on the core to a blow mould 65 (Fig. 3, not shown) where compressed air is applied through passages 36, 25 in the core to force down a piston 30 to which is attached the tip 32 of the core, and thereby to enter the parison and blow it. In Fig. 4, a parison 73 is extruded between the halves 75, 76 of a conditioning chamber 74 which are closed about it to pinch off the end 73a. The parison is severed from the extruder 70 by a knife 69 and a heat transfer head 85 (Fig. 5, not shown) enters the open end to displace it into engagement with the opening of the chamber. Heat transfer fluid is circulated within the parison through passages in the head (85) and around the parison through passages 78, 79 until it is ready for blow moulding.