Multiple utilization of blow-mold air

A procedure for molding a container from a thermoplastic material in a mold including first and second portions movable between open and closed positions, said procedure including:

• forming a moldable object by an injection molding process;
• storing said moldable object;
• heating said moldable object;
• feeding said moldable object into a mold in a blow station;
• stretching said moldable object in the direction of a longitudinal axis of said moldable object by use of a stretching rod actuated by a cylinder;
• pre-expanding said moldable object within said mold by the addition of a first low pressure air from a first low pressure component;
• expanding said moldable object within said mold by the addition of high pressure blow air;
• feeding said high pressure blow air to said first low pressure air component during a transition phase and after said moldable object has been formed to the contour of said mold but before said contour has been stabilized by cooling, said first low pressure air component being operable as a low pressure supply;
• monitoring the pressure in said first low pressure air component as said high pressure blow air is fed thereto to limit said pressure to a predetermined maximum;
• allowing said moldable object to cool to stabilize said contour and thereby form said container;
• feeding a portion of said high pressure blow air remaining in said container to a second low pressure air component, said second low pressure air component working at a lower pressure than said first low pressure air component;
• thereafter venting said high pressure blow air remaining in said container to atmosphere;
• opening said first and second portions of said mold;
• removing the molded container from said mold;
• and
• utilizing low pressure air from one of said first and second low pressure air components to carry out a pneumatic working step other than pre-expansion of said moldable object within the mold.