Water injected compressor for pure air
September 1st 2005

In the ultra sterile environment of the pharmaceutical production industry, stringent precautions are applied at every stage of manufacture to ensure total freedom from contaminants.

Standards are no less demanding in the manufacture of plastic packaging for pharmaceutical and health care products and they apply especially to the quality of compressed air that is used to operate plastics moulding machinery.

That is why Kent-based packaging specialist, Superfos Pharma has installed an Atlas Copco AQ water-injected screw VSD compressor, an innovative concept that combines the benefits of pure oil-free air, a high-pressure capability, and improved energy efficiency - the result of extremely effective water cooling of the unit.

Even the bearings are water lubricated.

No oil is present within the AQ’s unique new technology compressor element. It produces near-isothermal compression and contributes to a compression energy efficiency increase of some 20% over more traditional methods. The compression element features the new technology of optimised-profile polymer ceramic rotors supported by water-lubricated hydrodynamic and hydrostatic bearings.

The plastic container manufacturing plant of Superfos Pharma Pack in the UK, located in Sevenoaks, is part of an international specialist packaging organisation. In order to meet the dual sourcing requirements of its customer base, production equipment and output is replicated at its Vaerloese counterpart in Denmark, which is also the European HQ of the company.

Production of patented child proof and senior friendly HD polyethylene container bodies involves a number of methods, such as conventional Injection moulding as well as injection blow moulding and stretch blow moulding. All processes are closely controlled to comply with FDA standards and to provide full traceabillity.

Operating 24-hour, five-day week shift pattern, the moulding units are highly dependent upon a continuous supply of high quality compressed air. The original compressor installation, completed back in 2000, comprised an Atlas Copco ZT 55 oil-free rotary screw compressor, coupled to an FD 230 refrigerant dryer, outputting a constant 7.5 bar supply.

When reviewing his plant air requirements, in the light of new end product designs and output targets - plus the need for a more flexible air pressure range for specific processes - Steve Amner, Production Manager of the Superfos Pharma Pack plant, found all the right answers to his needs in the AQ water injected, variable speed drive compressor.

As he says: "Firstly, as an ISO9000/2000 accredited manufacturer, we have the peace of mind that we have in place a guaranteed oil- and contaminantfree air supply. Because of the variable speed drive facility, we can utilise process air at 13.5 bar for Stretch blow and injection blow moulding at 7.5 bar for injection moulding and the majority of the other ancillary operations. What’s more, we have a unit within the workplace occupying the minimum footprint - and it is so quiet, there are no more noise complaints from the staff in the adjacent warehouse and offices!"

Although it is still early days yet, based on Steve Amner’s positive experience with this innovative compressor facility, it is possible that the AQ concept will find favour in future plant upgrades within other production facilities throughout the Superfos group.

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