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Air/Oil Separators

When it comes to air compressor parts, it can be difficult to know exactly what you may need, and when you may need it. Below we take a look at air/oil separators; what they are, how they work, how to tell when you need a new one, and what products and services Edmac can provide.

What is an Air/Oil Separator?

To put it bluntly, an air/oil separator is a filter-like part that separates the oil from the compressed air.

During the compression process, oil is injected into the air compressor to lubricate, seal and absorb the heat of compression. Then, what comes out of the compressor element is a mixture of compressed air and oil. The air/oil separator separates the oil from the air, as the oil needs to stay inside the compressor to keep it lubricated while the compressed air needs to exit the compressor, free of oil.

How does an Air/Oil Separator Work?

Most of the oil in an air compressor is separated by a centrifugal force, which is the outward force that is created by circulating the air in the compressor tank. The air/oil mixture enters the separator vessel at an angle, so most of the oil gets pushed outside and drops down into the oil vessel. Usually, there is a splash plate installed that prevents the air-oil mixture from hitting the separator filter directly, and 85% of the oil is separated this way. The remaining 15% exists the compressed air as small droplets and mist. As this oily compressed air flows through the separator filter, the small droplets combine and form large drops until they fall and collect at the bottom of the separator filter. This oil is then sucked up and removed by the scavenge line.

How Do You Know When You Need a New Separator?

Here are some basic checks you can complete yourself to determine if you need a new air/oil separator

  • Physically inspect the separator. Should there be a lot of oil inside the separator, then the scavenge line is faulty, not the separator.
  • Should the oil level at the base of the element be higher than five centimeters this will indicate that the separator is starting to saturate, which means that the filter media is filling up with oil. Check to see if the catch-plate is faulty. If not, it might be time to change your separator.
  • Should the separator feel heavy, looks dark in color and is saturated from the bottom to the top, it is time to replace your separator.
  • Check using proper equipment while the air compressor is running loaded. The differential pressure should not be above 0.2 to 0.3 bar under load. If it is higher, it might be time to replace your separator.

How to Replace an Air/Oil Separator

  • Ensure the air compressor is not running, then open the separator vessel and replace the separator filter.
  • Ensure the new filter is the same size as the old one. If it is longer or shorter, adjust the length of the scavenge pipe.
  • Make sure to use proper gaskets, as these contain a metal conductor. This prevents static electricity from building up in the separator, which could cause sparks and potentially could lead to a separator vessel explosion.

At www.Edmac.com, you can find thousands of air/oil separators from all of the major OEM brands. All of our own Edmac-branded filters meet or exceed OEM specifications and are competitively priced to save you money, while still delivering the performance you need. Our parts benefit your equipment by preventing unwanted airborne particles, water, microbes, and chemical gases from entering your compressors.

We sell multiple brands and sizes of air/oil separators, and each product we sell is backed by our Edmac Guarantee, which ensures you get fast shipping, excellent customer support, and high-quality performance products.

Feel free to browse our full collection of separators. If you have product or compressor-specific questions, please call our product specialist team at (800) 866-2959.