| 摘要 |
The requirement for the accuracy with which process parameters are maintained in the making of flat bottles from a plastics parison extruded and blow-moulded in two stages can be reduced if the intermediate moulding produced in the first blow-moulding stage is kept under a supporting-air pressure from the instant of its venting in the intermediate mould until it is subjected to blowing air in the final blowing mould. For this purpose, the blowing mandrel of the extrusion blow-moulding machine may either be equipped with an additional shut-off valve close to the blowing opening or comprise a special valve which maintains the desired supporting-air pressure in the intermediate moulding. |
