Air Compressors Buyer's Guide Part 2

Assessing Your Quality Requirements

Bizarre as it may initially sound, the pressure and rate at which an air-compressor can deliver air are not the only considerations in relation to its output. Depending on the application it can be very important to ensure that the quality of the compressed air delivered meets certain requirements. To this end then; if you are pumping up car tyres, filling scuba tanks or cleaning micro-processors, you will consider different levels of air quality acceptable. Here are the main considerations and ways you can deal with them:

Oil

Like most machinery, air compressors need oil to lubricate their moving parts. Given that the act of compression requires the air to come into contact with at least some of these moving parts; it is not uncommon for the compressed air produced to have traces of engine oil present in it. If you are simply using pneumatic tools then this needn’t be a problem, as they are likely to be tolerant of some oil in their air supply. However, in medical applications for instance, this would be unacceptable and perhaps even dangerous. Given your use then, you have the choice of applying a filter to a regular air compressor or purchasing what is known as an oil-free compressor. The former will clean (to a certain extent) the air produced but when absolutely clean air is required, it is unlikely to suffice. Oil-free or oilless compressors on the other hand, although much more expensive, are the only way to make absolutely sure that your compressed air is free of all oil traces, as they specifically separate the air and oil throughout the compression process.

Moisture

Although some climates are more humid than others, there is always water vapour present in the atmosphere. As ambient air is compressed, this vapour often then condenses into water droplets. Again, with basic applications and machinery this needn’t be a problem. With sensitive equipment, however, prolonged exposure to moisture from your air compressor can cause severe damage. The most effective solution to this problem is the use of an additional drier. Driers can be purchased separately and fitted to most compressors but also come as standard with many industrial air compressors.

Temperature

Anyone familiar with basic physics will be aware that when a gas expands, it cools. The inverse is also true; when a gas is compressed it becomes hotter. As such, the use of compressed air will always be susceptible to temperature fluctuations. The most common temperature related problem is that the air delivered from the compressor, having been rapidly compressed, is too hot for its application. This problem may be solved with a cooler, which works much in the same way as an air-conditioning unit. Coolers can be bought separately or, again, may come as standard on the more heavy-duty types of air compressor.

Noise

It is perfectly acceptable for a mechanics’ garage to be a noisy place. However, the same level of noise would be absolutely unacceptable in a dentists’ surgery. As such, it is important to consider the noise that your air compressor is likely to make and how, if necessary, to minimise it. Due to their design some air compressors, especially rotary or screw compressors, are much quieter. When noise is a serious consideration then, it is wise to consider a screw compressor but you could also get around this problem by housing your compressor in another room or building, should you have the available space.

And Finally...

Although it’s important to correctly asses your needs, you needn’t worry if t you are not absolutely sure which air compressor is right for you. There are plenty of specialist air compressor suppliers out there and with a reasonable understanding of your needs, they should be able to give you some sound advice and perhaps raise some points not discussed in this article.