PET stretch blow molding needs high-pressure air, typically 30–40 bar, delivered in rapid pulses. The compressor is not auxiliary equipment; it determines cycle rate, bottle quality and energy cost.
Understand the Two Pressure Stages
- Low-pressure air (7–10 bar) for preform handling and valves
- High-pressure air (30–40 bar) for actual blowing
Sizing for Pulse Demand
Blow molding consumes air in short bursts. Size the high-pressure stage to the machine blow volume per cycle and the number of cavities, then add storage to smooth peaks.
Air Recovery Saves Energy
A recovery system returns exhaust high-pressure air to the low-pressure network, cutting total compressed air energy use significantly on multi-machine lines.
Air Quality Requirements
Bottles for food and beverage need oil-free, dry air. Filtration and drying at the high-pressure stage protect both product quality and blow valves.
Selection Checklist
- Confirm blow pressure and volume per cycle
- Choose oil-free high-pressure stage for beverage
- Add receiver capacity for pulse smoothing
- Evaluate air recovery ROI