In a compressed air network the right choice of air filters not only safeguards the health of the equipment in the network but also prevents higher power consumption in the compressor.
Atmospheric air carries both dust and moisture. Although some water, dirt and moisture will be removed by separators, there will always be some that will be carried over. Additionally the scales formed in the pipework, other foreign matter and burnt compressor oil are also present in pipe-work. The moisture in air and the traces of lube oil mix to form a gummy mix, which attracts dust and contaminant particles to form lumps which eventually clog the system. These clogs will create a pressure drop, leading to higher power consumption in the compressor. Thus in the compressed air network, it is important to choose the right air filter.
Filter elements can broadly be divided into two categories. The first is a surface type element, which has uniform pore size of material throughout its depth, and whose useful service life is depends on the free surface area of the filter element. Perforated or mesh screens and sintered metal come in this category. The second type of filter uses a graded density cartridge in which the pore size decreases in the direction of the flow. Here, in addition to the dirt which collects on the outer surface of the element, the filter element will also hold substantial quantities in the core of the cartridge, and this increases its useful life.
Filter elements are normally rated in microns, and this rating gives an indication of the finest particle that will be stopped by a clean element. It is not advisable to use a finer filter element than is necessary, because this will decrease the filter’s working life. Additionally it will also add to the pressure drop in the network.
Contaminants should be removed from the compressed air network as all of them negatively impact the end user equipments in the network. Additionally, by clogging the pipes and increasing the pressure drop, these contaminants also lead to higher power consumption in the compressor. Thus it is important to choose the right air filter. Additionally, these filters should be installed as near as possible to the point of use.