Compressed Air Filter: Surface Filtering

How does surface filtering work?

A surface filter is used to separate unwanted particles from compressed air. When compressed air comes to a surface filter, the idea is that the compressed air passes through, while the particles and pollutants are blocked and collected.

This works because there are holes in a surface filter. The actual size of these holes depends on the filter. Any particle bigger than the holes will be blocked.

What size filter?

If you want to block particles of incredibly small size, you’re best using a number of filters, with progressively smaller holes on each filter. Why not just start with the smallest holes? The filter will soon become blocked, and the compressed air will lose pressure or even be stopped from travelling through the filter. But by starting with larger holes and working your way down, you’ll capture larger particles first, while still allowing smaller particles to pass and be trapped by subsequent filters.

If a surface filter is blocked? Remove it and, depending on the type of filter, clean it or replace it. 

What size filter do you need?

The level of quality you need in your compressed air will decide the filter you need. The higher the quality required, the smaller the holes in your filter to ensure you filter out those tiny particles.

You may also need an air dryer to help remove water vapour from your compressed air. Once again, this will depend on what you’re using the compressed air for. 

Would you like a hand choosing the right filtration system for your system? Do you want to know more about air dryers? Great! There is nothing we would rather chat about. Get in touch today! 


Do you have an idea for our #expertcorner?Β Let us know!

Who we are and how Ash Air can help your business!

Ash Air has been around in New Zealand since 1979, and we’ve grown into a nationwide company with international support and a reputation for quality and reliability.We look after all things compressed air for your business!

  • Rotary Screw and Piston Air Compressors
  • Vacuum Pumps and Blowers
  • Nitrogen Generation
  • An extensive line of Air Treatment components
  • AIRnet Piping System and  Filtration
  • Mobile Compressors, Generators, and Light Towers

Ash Air's range of Chicago Pneumatic, ALUP, Pneumatech, and Atlas Copco products are used extensively around the world in industries ranging from oil and gas to food, automotive and farming, and we bring you these world-class compressors here in the land of the long white cloud.Our technicians are compressed air equipment experts and are dedicated to addressing customer needs. Supported with nationwide coverage, Ash Air offers one of the widest selections of compressed air, vacuum pump, and industrial gas equipment and parts available today in New Zealand.

Reliability and Efficiency

With Ash Air, you can count on reliability and high performance for even the most demanding applications. We focus our efforts on the following:

  • Increasing uptime
  • Reducing unexpected repairs
  • Reducing energy consumption and meeting our sustainability goals
  • Improving the cleanliness of compressed air


Talk to the team today:  CONTACT US CONTACT US

Read more from our #expertcorner


That cold, rainy, and in some places icey New Zealand winter is upon us, and with the following air compressor tips, your air system will be prepared with the preferred temperatures, despite the weather outside. Regardless of whether or not it actually snows or freezes up where you live, most winterisation service recommendations are also basic, solid maintenance procedures that will help extend the life and operational efficiencies of air compressors regardless of whether you live in Queenstown or Northland.


If you're wondering what an air compressor actually is, you've come to the right place. Simply, air compressors convert power in to air that is pressurised which is then used to power air tools such as spray guns. Air compressors are used in a wide range of applications, so naturally if you want one that will be designed for spray painting your vehicle, you want a compressor specifically made for spray guns! This way your compressor will be able to provide the right amount of power to perform the job.