A blow moulding apparatus includes a blowpin 1 and a dedicated air control system for optimizing the blow moulding operation. The air control system comprises an air supply vessel 2 for holding typically 10 liters of air at a pressure of at least 8 bar. Pressurized air is delivered through a control valve 6 to the blowpin 1. A pressure sensing valve 8 senses the air pressure in the vessel 2 and if the pressure falls below a preset value a signal is outputted to a controller 9 which disables operation of the blow moulding station. The temperature of the air is also controlled to be about 8° C. by a temperature sensor 10 which also provides a signal to the controller 9. Air may be exhausted into an exhaust vessel 15 maintained at a negative pressure before exhaust to atmosphere. Cycle time is reduced and product quality is improved.
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