Compressed Air and Surface Filtering

In the process of producing compressed air from a screw air compressor, filters are essential. Strict purity requirements necessitate the removal of a range of impurities, including oil aerosols, vapors, and particles, depending on the intended usage. There are several ways that contaminants can get into compressed air. Dust and pollen particles can be introduced via intake air, and dangerous particles from the compressor system can be added by corroded pipes. When using oil-injected compressors, oil aerosols and vapors are frequently produced as a byproduct that needs to be filtered out before final usage. varying compressed air applications have varying purity requirements, but pollutants can exist at unacceptable levels and cause dangerous or damaged goods. Coalescing filters, vapor removal filters, and dry particulate filters are the three types of filters.

Working of surface filtering

To remove undesirable particles from compressed air, use a surface filter. The principle behind a surface filter is that while the particles and contaminants are prevented and collected, the compressed air flows through. This is possible because a surface filter has holes in it. Depending on the filter, these pores can vary in size. The blockage will occur for any particle larger than the holes.

Types of filters for compressed air

Coalescing filters, vapor removal filters, and dry particulate filters are the three types of filters used for filtering air from a high pressure air compressor. Although they all work according to different principles, they all ultimately yield the same result. These are listed and explained in detail below:

1. Coalescing filters: Aerosols and water are eliminated via coalescing filters. Larger droplets are released from the filter after being combined with smaller droplets that were captured in a filter medium. These droplets are kept from returning to the atmosphere by a re-entrainment barrier. Water and oil are the main substances removed by liquid coalescing filters. Additionally, these filters remove particles from compressed air by trapping them in the filter media, which, if not replaced on a regular basis, might result in pressure decreases. Coalescing filters effectively eliminate the majority of pollutants, lowering liquid concentrations to 0.01 parts per million and particle sizes to 0.1 microns.
2. Vapor Removal Filters: Gaseous lubricants that are intended to pass past the coalescing filter are usually eliminated using vapor removal filters. Lubricant aerosols shouldn’t be captured by vapor removal filters since they work through an adsorption technique. In a matter of hours, aerosols will quickly saturate the filter, making it ineffective. This damage can be avoided by passing air through a coalescing filter before the vapor removal filter. To remove and trap impurities, the adsorption method uses carbon cloth, paper, or activated carbon granules. Because of its huge open pore structure—a handful of activated charcoal has the surface area of a football field—activated charcoal is the most often used filter material.
3. Dry Particulate Filters: After an adsorption dryer, desiccant particles are often removed using dry particulate filters. In order to rid the compressed air of any corrosion particles, they can also be used at the point of usage. Similar to a coalescing filter, a dry particulate filter collects and holds onto particles inside the filter medium.

Selecting the appropriate filter can be aided by being aware of your compressed air system requirements. Cleaning your air is a crucial phase in the compressed air process, regardless of whether it needs to have simple impurities removed or a high level of filtration. To find out how Atlas Copco can help you attain cleaner, safer air, check out their filter selection or give them a call.