Last week, we discussed several issues concerning the use of oil-lubricated compressors in food and beverage applications. While there are no guidelines that recommend which compressor type to choose – oil-lubricated or oil-free – being aware of risks associated with oil-lubricated compressors will help you make a better informed decision.
The Effect of Temperature on Compressed Air Purity
Lubricated air compressors introduce three forms of oil contaminant into the compressed air stream: aerosol droplets, vapor and liquid wall flow.
Lubricated compressors use filters to remove the oil from compressed air, but the purity of air is dependent upon the temperature. When using oil-injected compressors with oil removal filters, oil carryover through filter media increases exponentially according to the increase in temperature at the filtration interface.
Temperatures also cause an increase in the vapor content of the air, some of which can carry through to the end product. Moreover, high temperatures shorten the lifetime of activated carbon filters. An increase in temperature from 68°F to 104°F can cut filter lifetime by up to 90 percent. In air cooled compressors the discharge temperature can rise to as high as 120°F further reducing the lifetime of the filter. Even worse, the activated carbon filter does not warn the user when it is saturated; it will simply allow oil to pass on to processes.
Preventing a Catastrophic Oil Carryover
The failure of the air-oil separator proves to be another risk associated with lubricated compressors. A 300 HP compressor has a 25-gallon oil capacity and if the air-oil separator fails, oil passes to the process. This could spoil the entire compressed air pipeline and the end product. While preventive maintenance can help reduce this risk, there will always be the potential of a catastrophic oil carryover.
Oil-free Compressor Technology Offers a Safer Alternative
Oil-free compressors, certified by ISO 8573-1 Class Zero standards, are the less risky alternative to oil-lubricated compressors with filters. Not only do oil-free compressors offer reliability and energy efficiency, but they also offer peace of mind when it comes to food safety.
Did you know Atlas Copco is the first compressor manufacturer to receive ISO 22000 certification by Lloyds Register for our production facility in Antwerp, Belgium, setting a new standard for key suppliers to the F&B industry? This facility manufactures state-of-the-art oil-free air compressors, blowers and air treatment products.
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