Filtration Information

Intake air filtration is a necessity for blowers, compressors and other rotating equipment to prevent ingestion of particulate matter of all kinds: dust, dirt, sand, soot, ice, rain and debris. Selection of the proper intake filter is sometimes difficult because of the many variables: climate, contaminant, size and cost.

Westwood Equipment purchased the proven and efficent air filtration division develped and designed by EM Products. Westood Equipment has been manufacturing these proven design concepts for several years. In most cases the least expensive intake filter to buy may become the most expensive to maintain or even worse, cause a catastrophic failure of the equipment it was intended to protect. A filter which is too small for a given application will result in excessive filter replacement. It will also result in more contaminant being drawn through the filter itself due to excessive velocity. The lower the velocity of air through a filter the greater the filter’s efficiency. Further, if a filter is applied at high velocities it will act as a vacuum cleaner drawing contaminant to it. In cold climates, high velocity into a filter will cause icing of the filter, when moisture or snow is present. The formation of ice on the filter will cause the velocity to increase and rapidly constrict the filter totally with ice. In dry dusty conditions, high velocity will cause more contaminant to be drawn into the filter, again causing a more rapid rise in restriction and more frequent filter change outs.

Type of contaminant present in the area the filter is to operate plays a major role in filter selection. If the only contaminant present is large objects such as bugs or leaves, a wire mesh filter may perform well. But a wire mesh element has extremely high air to media velocities and will not filter fine dust or soot and will blind more rapidly when freezing moisture is present. If fine dust is present, a felt media or cellulose/synthetic (paper) filter will be necessary to prevent equipment damage. Size of the filter is critical in any case. In order to prevent the formation of ice on a filter, the velocity through the filter media must be 2.7 feet per minute or less. To prevent ingestion of snow into a filter the approach velocity into the filter must be less than 250 feet per minute. To prevent ingestion of rain the approach velocity into the filter must be less than 500 per minute. Historically, intake filtration has been applied at very high velocities in order to keep the size and cost of the filter down. This results in high restriction and frequent filter replacement.

Westwood Equipment offers the complete range of standardized filter systems including the high velocity types just described. Proper filter selection must be based upon the combination of economics and need. That is why Westwood Equipment recommends careful analysis of both the economics of original filter cost and on-going maintenance cost balanced with the level of filtration required.

Westwood Equipment offers very high efficiency filters utilizing moisture resistant cellulose/ synthetic blend filter media that will withstand high humidity and provide efficiency to 99.9% and greater.

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