Blog - Air Compressors

Choosing the Right Inline Compressed Air Filters for Air  Compressors

 

Date: March 22, 2021
Author: Peter Sawochka-Dalton and Peter Modrow

Not all compressed air is created equal—and not all compressed air systems perform the same. Your compressed air system must deliver the right flow, pressure, and air quality for your processes. A well-designed Atmos compressed air system supplies this air as efficiently as possible. A poorly designed one falls short in performance, efficiency, or reliability.

So, what exactly makes a well-designed compressed air system?

  • The Atmos compressor provides flow and pressure.
  • A compressed air dryer removes excess moisture.
  • Inline compressed air filters improve air quality further by removing moisture, particulates, oil, and other contaminants.

What Is Compressed Air Quality?

Air quality is simply a measure of how free the air is from contaminants. While dryers remove moisture, only compressed air filters can remove particulates, aerosols, and vapors.

Common contaminants in compressed air:

  • Particulates – dust, pollen, rust, and pipe corrosion.
  • Aerosols – fine oil mist and tiny water droplets.
  • Vapors – primarily oil and hydrocarbons in gaseous form.

The ISO 8573-1:2010 standard defines compressed air quality levels by contamination type. To meet these classes, you need the right type of inline air filter matched to your application.

Types of Inline Compressed Air Filters

1. Particulate Filters

Designed to trap solid particles. Filtration efficiency depends on the filter element material and design.

2. Coalescing Filters

Remove aerosols (oil and water) by coalescence—small droplets merge into larger drops that drain away.

3. Combo Filters

Some designs, such as the Atmos SX series threaded and flange filters, combine particulate and coalescing filtration in one unit.

4. Activated Carbon Filters

Target oil and hydrocarbon vapors, reducing oil carryover to as low as 0.003 mg/m³. Essential in industries like food processing and pharmaceuticals where air purity and odor control are critical.

Degrees of Filtration

Coarse Filters

  • Remove large particles (5–40 microns).
  • Reduce oil carryover to ~5 mg/m³.
  • Protect tools and instruments but don’t achieve high air quality.

Fine Filters

  • Capture particles as small as 1 micron.
  • Limit oil carryover to 0.1 mg/m³.
  • Often the minimum requirement for high-quality applications.

Superfine / Micro Filters

  • Trap particles down to 0.01 micron.
  • Limit oil carryover to 0.01 mg/m³.
  • Used in food, pharma, spray painting, and precision instrumentation.

⚠️ Why not just use a superfine or carbon filter?
Using the finest filter for all contaminants shortens its lifespan and increases replacement costs. For example, activated carbon filters can clog in hours if overloaded. Layered filtration is more cost-effective.

When to Replace Filter Elements

All filter elements eventually reach saturation and must be replaced. Clogged or saturated filters cause:

  • Higher energy costs (compressor works harder).
  • Increased contamination of finished goods.
  • Higher equipment wear and maintenance costs.

Delaying replacement may save on filter costs in the short term but leads to greater production expenses overall.

Typical Filtration Setups in Atmos Compressed Air Systems

1. Systems Without Dryers

  • Install a coarse or fine filter right after the Atmos compressor.
  • Upgrade to superfine if stricter filtration is required.

2. Systems With Refrigerated Dryers

  • Place a fine filter between compressor and dryer.
  • Add a superfine filter after the dryer.
  • Use activated carbon after the superfine filter if odor or vapor removal is needed.

3. Systems With Desiccant Dryers

  • Install a fine filter before the dryer.
  • Optionally, add a superfine filter before the dryer to extend desiccant life.
  • Install a fine particulate filter after the dryer to remove desiccant dust.
  • If needed, place an activated carbon filter after the fine filter.

 

 

 

 

Post Image
Back to Blog Listing
WhatsApp Icon

Recent Search Keywords