Air Supply UK: Specialist Compressed Air Engineers

Published: 01/03/2024

Do I need a filter on my air compressor?

Air filtration is vital to any compressed air system to ensure a consistent supply of clean air free from particles and contaminants. However, you’ll need to ensure that you install the correct type of air filter for your compressor and its usage. 

In this blog, we’ll cover everything you need to know about air compressor filters so you can decide if you need one and which type. We’ll include:

  • What is an air compressor filter?
  • Common types of air compressor filters
  • How does an air compressor filter work?
  • Do I need a filter on my air compressor?
  • How far should the filter be from the air compressor?
  • How to clean an air compressor filter

What is an air compressor filter?

The term air compressor filter refers to a range of filters used in compressed air systems to ensure a clean air supply. Filters remove contaminants from the air, such as dirt, dust, solid particles, water and oil droplets. Most compressed air systems will require several different types of air filters. 

Common types of air compressor filters

There are three main types of air filters:

  • Intake filters
  • Inline filters
  • Oil filters

Intake filters

These filters are positioned at the air intake to filter out any contaminants, such as pollen or dust, from the air before they enter the compressor. 

Inline filters

Inline filters are placed after the compressor and filter the already compressed air. They typically remove dry particles up to 1 micron in size.

Oil filters

Oil filters remove particulate matter from oil in oil-lubricated air compressors. They are necessary to ensure the longevity of your machine. 

How does an air compressor filter work?

Different air filters work slightly differently. Here’s an overview of how some common filter types work. 

Dry particulate filters 

Dry particulate filters trap dirt particles in filter media through inertial impact, diffusion or direct interception. Larger particles are blocked directly by the fibres, while smaller particles are blocked when they move erratically through the media and are held using electrostatic attraction.

This filtration mechanism is used in both intake and inline air filters. 

Coalescing inline filter

An oil coalescing air filter removes oil mists, oil vapours and dry particulates from already compressed air. This filtration mechanism works using layers of a fine mesh material which traps mists and aerosols. They then collect on the surface of the mesh material until the droplets are heavy enough to fall. The liquid is collected at the bottom of the inline filter and drained away. Small particles are drained away with the liquid, while larger particles are trapped in the mesh material.

This filter can remove droplets and particles down to 0.01 microns and the remaining oil to .008 PPM. 

Adsorption filters

In an adsorption filter, molecules or particles stick to the adsorptive material inside the filter cartridge. Adsorptive materials like activated carbon have many tiny micropores to increase the surface area, so molecules are trapped in the micropores. This should be used with a compressed air dryer and a coalescing filter to remove oil mists and dry particulates from the air before entering the adsorption filter.

Air compressor oil filters

Air compressor oil filters work similarly to a car oil filter. They remove coarse contaminants from the oil in an oil-lubricated compressor. Oil filters help protect oil compressors from wear and tear and increase their lifespan.

Do I need a filter on my air compressor?

Contaminated air can cause problems for your compressor and the equipment it powers. Although clean air is more important in some applications than others, partially in medical, dental or food industries, it can still be useful in the vast majority of compressed air applications. Without correct filtration, contaminants will end up in your compressed air systems and equipment. 

Here are some problems that can be caused by contaminated compressed air:

  • Increased inefficiency. Contaminants in the air can cause your pneumatic tools and equipment to perform inefficiently, which increases your operation costs.
  • Damage to tools and equipment. Contaminated air can cause corrosion or blockage in your compressed air system, leading to excess wear and tear on your machine and the tools it powers.  
  • Contaminated products. Contaminated compressed air can contaminate your final products in specific industries, affecting their quality.
  • Increased wear and tear. A lack of filtration means your compressor will need more frequent maintenance, cleaning and repairs, which increases your costs. 
  • Higher likelihood of repairs and breakdown. Similarly, contaminated air means your compressor will break down more regularly, negatively impacting your business’s productivity.
  • Increased health and safety risks to your employees. Contaminated air can lead to illness or respiratory infections if employees work close to a compressed air system with no filtration. 

How far should the filter be from the air compressor?

Inline filters should always be installed after the compressor in the system. They should be as close as possible to the point of use and as far away from the compressor as possible for maximum efficiency. 

How to clean an air compressor filter

You should check the instruction manual that’s specific to your filter, but here are some general steps you can follow to clean your filter:

  1. Turn off your compressor and let it cool.
  2. Unscrew and remove the filter’s top cover.
  3. Look for any damage to the top cover, remove the filter from the base and inspect it for any issues. 
  4. If there is damage or the filter has been in use for over 6 months, you should replace your air filter. 
  5. If it doesn’t need replacing, use low-pressure compressed air to remove dust or dirt from the filter gently. 
  6. Apply a cleaning solution, let it soak in and then thoroughly rinse off the filter.
  7. Reattach the filter in its original position and reattach the top cover.

How Air Supply can help

At Air Supply, we have decades of experience selling, servicing, and repairing a huge range of compressed air treatment equipment, including a range of air filters and air dryers. We also stock both used and new air compressors at competitive prices!

Our expert team also offers comprehensive maintenance, servicing, and repair services. If your compressed air system is not performing as it should or requires its annual service, we would be happy to help.

 Get in touch with us today to find out more about our products and services, or speak to a member of our team if you’re still unsure if your compressor could benefit from a filter. 

 

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