Regulators and Filters for Compressed Air

I would like to dive into the realm of filters and regulators. Majority of EXAIR products use compressed air to coat, conserve, cool, convey or clean. So, to keep the product running efficiently, we need to supply them with clean, dry, pressurized air. We offer a line of filter separators, oil removal filters, and regulators that can supply enough pressure and flow to keep the EXAIR products performing for a very long time. If we look at each individual item, we can see how they can play an important part in your compressed air system.

Regulators are used to control the amount of air pressure being supplied to your EXAIR products. This is important if you are trying to control the flow, force, and/or conveyance rate. One issue with regulators is “droop”. Droop is the amount of pressure drop when you flow through a regulator. If you set the pressure of a regulator with no flow, to let’s say 80 psig (5.5 barg). Once you start flowing, you will see the downstream pressure fall. This is dependent on the size of the regulator and the valve inside. This is very important because if you need 80 psig (5.5 barg) downstream of the regulator feeding an EXAIR product and the droop brings it to 30 psig (2 barg), you will not have enough flow for your EXAIR product, losing performance. EXAIR recommends a specific regulator for each of our products. We tested our products with the recommended regulators to make sure that you are able to get the best performance. If you do use another manufacturer’s regulator, make sure you are able to flow the correct amount of air at the pressure you need. Not all ¼” regulators flow the same.

Pressure Regulator
Pressure Regulator

Filter separators are used to remove liquid condensate and contamination from the compressed air stream. They have a 5 micron filter and work very well if you get a slug of water or oil into your compressed air system. They use mechanical separation to remove the large particles of dirt and water from the air stream. Most facilities have some type of compressed air dryer in their system. This will dry the compressed air. But, if a system failure occurs, then water, oil, and dirt are pushed into the compressed air lines and perhaps into your EXAIR products. Even if you have good quality air, it is important to keep your products protected. An ounce of prevention ….

Oil Removal Filter
Oil Removal Filter

 

The oil removal filters are used to keep the compressed air even cleaner yet. They work great at removing very small particles of dirt and oil. Without an oil removal filter, dirt particles and oil particles can collect in “dead” zones within the compressed air lines. Over time, a tacky glob forms. As it grows, it can break off and get into the air stream affecting pneumatic devices. The oil removal filter will be able to help eliminate the long term effects in your compressed air system. As a note, oil removal filters are not great for bulk separation. If you have a system with lots of water, you will need a filter separator in front of the oil removal filter to optimize the filtration. With the oil removal filters, the media is a barrier to collect the small particles of dirt and oil. If a slug of water or oil tries to go through, it will block a portion of the element off until it is forced through. This will increase the velocity and pressure drop of the element. With the high velocity, as the slug makes its way through the media, it can spray, re-entraining the liquid particles.

Now that we went through our pneumatic products, how do we use them together to get the best supply of compressed air? With both types of filters, we always want them to be upstream of the regulator. This is because the velocity is lower at higher pressures. Lower velocities mean smaller pressure drops which is good in filtration. If we can analyze the compressed air systems, I would like to categorize it into a good and premium quality. To supply a good quality of compressed air, you can have the compressed air run through the filter separator then a regulator. To produce the premium quality of compressed air, you can have your compressed air run through the filter separator, the oil removal filter, and then the regulator. With clean quality air, your EXAIR products will provide you with effective, long-lasting performance without maintenance downtime.

John Ball
Application Engineer
Email: johnball@exair.com
Twitter: @EXAIR_jb

Why 5 PSIG Matters

Last week I pointed out the important locations for measuring your compressed air system pressure throughout your compressed air system.   One of the critical points to measure system pressure was before and after each filter.  This leads into another question that I receive every once in a while, “How do I tell when the filter needs to be changed?”  The answer to this is easy, when you see more than a 5 PSIG pressure drop across the filter.  This means that the element within the filter has become clogged with sediment or debris and is restricting the volume available to your downstream products.

Filter
EXAIR 5 micron Auto Drain Filter Separator

 

This can lead to decreased performance, downtime, and even the possibility of passing contaminants through the filter to downstream point of use components.  In order to maintain an optimal performance when using EXAIR filter separators and oil removal filters, monitoring the compressed air pressure before and after the unit is ideal.

Replacement filter elements are readily available from stock, as well as complete rebuild kits for the filter units. Changing the filters out can be done fairly easily and we even offer a video of how to do it.

The life expectancy of a filter element on the compressed air is directly related to the quality of air and the frequency of use, meaning it can vary greatly.  If you tie a new filter onto the end of a compressed air drop that has not been used in years, you may get a surprise by the filter clogging rather quickly.   However, if you maintain your compressor and your piping system properly then the filters should last a long time. Generally we recommend checking your filters every 6 months.

If you have questions about where and why to filter your compressed air contact us.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF