Compressed air filters help to keep the air clean and condensate free to protect equipment from dust, dirt, pipe scale, oil and water. Even though the compressed air system will typically have a main dryer, additional treatment is often necessary. For this discussion, we will focus on the oil removal process and filter type.
After the compressed air has passed through a particulate filter, the dirt, dust and water droplets have been removed. Oil that is present is much smaller in size, and mostly passes though the particulate filter. The installation of a coalescing filter will provide for the removal of the majority of the fine oil aerosols that remain. The coalescing filter works differently than the particulate filters. The compressed air flows from inside to outside through the coalescing filter media. The term ‘coalesce’ means to ‘come together’ or ‘form one mass.’ The process of coalescing filtration is a continuous process where the small aerosols of oil come in contact with fibers of the filter media. As other aerosols are collected, they will join up and ‘come together’ and grow to become an oil droplet, on the downstream or outside surface of the media. Gravity will then cause the droplet to drain away and fall off the filter element.
Some important information to keep in mind –
Change the filter regularly, not just when the differential pressures exceeds recommended limits, typically 5 PSI
Coalescing filters will remove solids too, at a higher capture rate due to the fine level of filtration, using a pre-filter for solids will extend the life
Oil free compressors do not provide oil free air, as the atmospheric air drawn in for compression contains oil vapors that will cool and condense in the compressed air system.
If you would like to talk about oil removal filters or any of the EXAIR Intelligent Compressed Air® Products, feel free to contact EXAIR and myself or one of our Application Engineers can help you determine the best solution.
In the application shown above the end user needed to remove excess lubricant from the outside of a tube after a forming process. The existing setup offered no removal of the excess oil, and as the tubes exited the machine, oil would fall from the tubes and drip onto the floor. To prevent these oil drops from reaching the floor and accumulating into a potential safety hazard, paper towels were placed at the exit of the machine to catch the oil and replaced as needed.
Considering that a blow off solution was needed to provide coverage to the full OD of the formed tubes, this application was an excellent candidate for a Super Air Wipe. The Super Air Wipe provides 360° blowoff for the tubes, removing excess oil as the tubes pass through the air stream of the Super Air Wipe.
An added benefit for this application in blowing the excess oil back into the machine was the need for lubrication on the machine components on the “leading” side of this application. As the tubes exit the machine, no oil is desired; but on the preceding side of the machine, oil is very much needed. Using the Air Wipe to remove excess oil from the tubes and simultaneously blow this oil back into a needed workspace made this product the perfect fit.
The exact model chosen for this application was the 2404, 4” Super Air Wipe. Available from stock with same-day shipping, we were able to meet the needs of this application while exceeding customer expectations.
If you have a similar application or would like to discuss your application needs with us, contact an EXAIR Application Engineer. We’ll be happy to help.
Have you ever walked into an industrial plant and noticed a “fog” in the air? If they have pneumatic equipment, then it is a good chance that it is an oil mist. With many pneumatic devices, they need oil to lubricate the o-rings and cylinders for functionality and life. This is generally done with a lubricator. A lubricator puts a small amount of oil in the compressed air line to coat the inside of valves and cylinders. The problem becomes when the valve switches or the cylinder retracts, the excess air is exhausted into the atmosphere. And with that air, there is a fine mist creating the “fog”.
Most pneumatic equipment will have some type of muffler to reduce the noise. Typically they are a sintered bronze muffler. They work well in noise reduction, but they do not capture the oil. OSHA (Occupational Safety and Health Association) has a requirement for operator’s exposure. Under the standard 29CFR 1910.1000, the cumulative exposure for a worker is 4.32 PPM (parts per million) for an 8 hour shift and a standard 40 hour week. As EXAIR Corporation is a leader in safety with compressed air systems, we created a muffler with an oil coalescer, or our Reclassifying Muffler. The Reclassifying Muffler will be able to accomplish two things: 1. reduce the noise level, and 2. remove the oil from the exhausted air. The complex matrix of fibers absorbs the noise caused by the pressure relief. Also, this same complex matrix of fibers creates a tortuous path for the oil particles. It will collect on the fibers and coalesce into larger particles. The larger oil particles will now be able to have gravity move the residual oil down the side of the Reclassifying Muffler. At the bottom, we have a sump that will contain the waste oil and a ¼” tube adaptor to discard it safely away. We have a range of sizes from 1/8” npt to 1” npt depending on the amount of exhaust air flow. In some instances, you can manifold the lines together to use one larger Reclassifying Muffler. An instance of this would be many small valves inside an electrical cabinet that would need to have the exhaust air removed. With our range of Reclassifying Mufflers, you will not have to walk around in the fog.
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.
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.
The video below will give a brief demonstration on the importance of point of use filtration in order to remove unwanted material such as water, scale, particulate and oil from your compressed air stream. Point of use or end-use filtration will keep your air clean and your compressed air products running smooth. If you have any comments or questions, please feel free to contact us.
I would like to discuss the importance of clean and dry filtered air. This all comes from some discussions I have had with customers over my time here at EXAIR, as well as from my time in the machine tool industry. It is notable to state that we simply ask for clean/dry air to run through our products, not “instrument” or “process” air which is typically held at a different pressure, temperature, or volume and can be more expensive to generate. All of EXAIR’s products use general plant air and can be cleaned up with simple point of use filters.
Clean and dry compressed air is essential for ensuring a long and easy life of almost any compressed air product. One product in particular that I have some data on is the EXAIR Line Vac. The pictures below show the inside wall of a Stainless Steel Line Vac. This unit was used in a harsh outdoor environment. The compressor was not maintained and did not have any form of filtration on the lines feeding the Line Vac unit. The first picture shows where all the dirt and particulate were impacting the internal generator wall as it entered the air chamber.
The two dark grey marks are actually the impact points on the unit. There is only one air inlet on the Line Vac, this means that the unit was taken apart during the two months and actually inspected then put back together and the generator was rotated slightly during this process. These spots are similar to what sandblasting does to metal, just to illustrate how much particulate was in the air stream. Since the air has not yet reached its full velocity within the Line Vac, it has left only those visible surface blemishes.
As the air begins to exit the array of small generator holes it begins to rapidly increase in velocity while it is trying to expand to atmospheric conditions. Because of this increased velocity, the wear the generator holes experience is greater and as seen below it is causing some extreme wear.
To give you an idea of what a new generator should look like is below. Here you can see uniform holes that go precisely through the generator.
To prevent a disaster like this from happening to your end-use compressed air products, all you need are some simple, low maintenance filters. EXAIR offers dirt / water filter separators that will filter your compressed down to 5 micron particulate size. The will catch the good majority of rust, water, and dirt within your compressed air system. Then you can also install an oil removal filter which will filter all oils and particulate out of your compressed air system down to 0.03 micron particulate level.
Each of these units are great point of use filtration to keep any of your processes from experiencing what this Line Vac experienced. If you have any questions about the quality of your compressed air or why you are seeing failures in product on your compressed air system, contact us.
I have been reading Kyle Thill’s blog over at Toyota Forklift, and he often speaks about the benefits of preventative maintenance and service schedule. With our products preventative maintenance can be the last thing on anyone’s mind, but it is important work to keep your compressed air systems clean and dry. Today I received a reminder of this.
We received a Heavy Duty Line Vac back from a customer today, who had taken us up on our offer of a 30 day Unconditional Guarantee. It was no problem for us to take the unit back, but as we were taking it apart, we received a gentle reminder how important it is to use clean dry air with our products and to use compressed air filters on your compressed air lines.
On the right, we have a photo for Heavy Duty Line Vac for reference. As you can see, a new Heavy Duty Line Vac will have clean metal surface inside the inlet. When our quality department inspected the used unit returned from the customer, we found this pile of rust particles that had been deposited inside the unit, right at the air inlet position. One of the reasons filters are so important with new equipment is that the increased load can dislodge contaminants that may have been building up inside old compressed air lines. The other reason we always recommend compressed air filtration is because filters prevent debris from ending up on anything you blow off, cool, move or coat with our products. Compressed air lines can carry oxidized metal, water or oil contaminants, which can be easily removed to ensure your products and ours are kept clean.