The importance of oil-free air for PET blowing compressors

Many bottlers take extra steps toward purity with decontamination after blow moulding of the preforms. Even the slightest traces of oil can result in altered or toxic product batches and health hazards for the consumers, recalls and reputation damage, as well as costly production downtime and cleanup. With the Atlas Copco 40 bar ZD high-pressure compressors, risk of any contamination by oil is effectively eliminated during PET bottle blowing for the bottled water, soft drink, fruit juice and beverage industries.

Testing of the compressor was carried out by the renowned independent Technische Überwachungs-Verein (German Technical Monitoring Association, or TÜV), using the most stringent test methods available. All possible forms of oil contamination as liquids, aerosols and vapours were measured at three different temperatures (20, 40 and 50°C) and at different pressures (25, 30 and 40 bar) at the measurement point. Even so, no traces of oil were found in the output air stream.

The ZD 40-bar compressor is the latest of Atlas Copco's oil-free technologies to obtain the ISO 8573-1 CLASS 0 certification with regard to oil content. Claimed as the first manufacturer to obtain the Class 0 certification for its Z series of oil-free rotary screw compressors in 2006, Atlas Copco quickly confirmed certification of its other oil-free technologies: the centrifugal, tooth, scroll, piston and water-injected screw. Together these span the pressure range from 300 mBar to 40 bar and up to 26,000 m³/h. This lastest certification highlights Atlas Copco's ongoing commitment to the purity of air and the quality of its customers’ products.

Reducing energy costs
Atlas Copco’s ZD with integrated heat of compression dryer has a specific energy requirement using four-stage compression (thermodynamically, the four-stage build-up helps to lower energy consumption by 7% compared to a three-stage build-up).

Another innovation is an integrated variable speed drive (VSD), which is particularly useful if bottle sizes change frequently. With the VSD, up to 35% energy savings can be achieved. Suitable for all re-injection installations, the RI VSD model can provide extra energy savings.

Reliability
The high volumes of PET production lines and their continuous operation mean that the reliability of PET blowing compressors is extremely important. Atlas Copco produces high-pressure air in four stages, achieving lower pressure ratios per stage. This means less wear-and-tear and reduced maintenance costs.

Reduced installation costs
Silencing canopies are standard, eliminating the need and cost for a separate compressor room. The ZD is delivered with a concrete base plate to absorb vibrations, so no foundation or fixation bolts are required; handling is via forklift.

The flexible ZD can simultaneously deliver both high-pressure air for blowing needs and medium-pressure air for labelling, instrumentation and capping; this eliminates the supplementary investment in a standalone medium pressure compressor. Both segments of the ZD can be installed directly adjacent to the blower.