If you have an Automatic Drain Filter Separator, or Oil Removal Filter, with a float drain that’s blowing by, then this video is for you. As always, though, give us a call if you have any questions.
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.
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 ….
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.
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.
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.
Today’s discussion is on dew point of air as it has a significant impact on a compressed air system. The dew point is the temperature at which the water vapor in the air can no longer stay in a vapor form, and condenses from a vapor into a liquid. The amount of water vapor contained in air is directly proportional to its temperature. The warmer the air the more space there is between molecules thus it is able to hold more water vapor.
It is when air temperature drops below the dew point that issues develop in a compressed air system. Let’s take the example of a warm summer day at 90 F and 50% relative humidity. From the chart we see the dew point temperature to be 70 F. So at night, when all the equipment is shut down and the temperatures drop into the 60’s, water will condensate throughout the entire system. In the morning when the equipment is turned on, water blows through sensitive valving.
Compressing air will increase the dew point. Hot compressed air exiting the compressor and cooling while it makes its way through distribution systems is one reason for condensate in compressed air lines. Drying the compressed air is recommended to reduce or eliminate water condensate problems in a compressed air system.
There are several methods to dry out your compressed air. Each have their advantages and disadvantages. The following short review of the various options will help you decide which is best for your application.
The compressor’s after-cooler which looks similar to a car’s radiator or the condenser in an air conditioner, is the first step to dryer air. It is placed at the compressor’s air outlet and uses either ambient air or water to cool the compressed air and condense some of the water vapor into a liquid that can be removed with a water separator.
The simplicity of design is a positive. The negative is that it can never cool below ambient but something above ambient depending on its capacity. After-cooler performance is rated by approach temperature, which is how closely the compressed air leaving the after-cooler will approach the temperature of the cooling medium used.
For example, if an air-cooled after-cooler is rated for a 10°F approach temperature, and the temperature of the ambient air is 90°F, the temperature of the air leaving the after-cooler will be 100°F. Assuming 50% relative humidity day the dew point will be 80 F.
Mechanical Water Separators
Wet compressed air enters the separator and passes through a set of vanes that spins it in a vortex. Centrifugal force causes liquid to fly out of the compressed air stream and run down the inside of the filter bowl, where it can be drained off. These are installed at the point of use as a final defense before entering sensitive compressed air equipment. They are an inexpensive assurance of quality air. The ones EXAIR has also include a sintered bronze filter element to remove dirt and scale as well as water.
A deliquescent dryer is basically a tank full of salt tablets. As the compressed air passes through the salt, the salt attracts water and dissolves into a brine that can be drained off. These are the least expensive dryers to purchase and maintain because they have no moving parts and require no power to run. The operating cost consists of the cost of more salt tablets.
Desiccant Air Dryers
These are similar to the deliquescent driers except they use a desiccant that attracts water but holds it. When they have reached their saturation limit they are either replaced or regenerated in one of three methods.
Operating cost of these dryers varies with the method used to remove water from or regenerate the desiccant.
Heatless regenerative dryers take a portion (about 15%) of the dry compressed air leaving the dryer and passes it through the desiccant to absorb the moisture out of it. Purchase cost economical but operational costs are high because if all the compressed air used to dry out the desiccant.
Heated purge regenerative dryers take advantage of the fact that hot air can hold more water than cold air. These dryers take about 5% of the dry compressed air leaving the dryer and pass it through an electric heater and then sends it through the wet desiccant bed. This dryer cost more than the heat less dryer but is offset by using half the compressed of that used by the heat less dryer.
Blower Purge Dryers
These are similar in concept to the had dryers found in restrooms but on a larger scale. Heated air is sent trough the desiccant with a blower. These are not quite as efficient because they are heating up ambient air which would not be as dry as compressed air.
Membrane Air Dryers
These dryers use pass the compressed air through a membrane with pores large enough to allow air molecules through but not large enough to allow water molecules through. The lower a dew point is needed, the more purge air is required. These
Refrigerated Air Dryers
Is an A/C system that refrigerate the compressed air as close to freezing as possible in order to condense out as much water as possible then use a mechanical water separators to remove the condensed water. They require electricity to operate along with the associated cost of operation and maintenance.
Hopefully this gives you a better understanding on how to qualify your compressed air.
Feel free to contact me at any time with questions or concerns, or if I can be of any further assistance. I genuinely appreciate the opportunity! 1-800-903-9247 or click on the live chat icon in the upper left hand corner.
You may notice that EXAIR offers most of our products in a kit form. These kits always contain a filter and pressure regulator with any other associated parts for a specific product. A filter is always a good addition to an end use compressed air application to keep the application running clean and effective.
A compressed air filter/separator is available with filter elements in different micron sizes to remove smaller or larger particles depending on the end use product you are using. All of EXAIR filters have 5 micron elements to remove solid contaminants and water condensate prior to running through the end use product.
It is first important to make sure the filter is sized properly for the peak flow demand of the compressed air product. We make sure all of the filters in our kits are sized properly for peak demand of the individual product. If multiple products are ordered and only one filter is desired for multiple end use products, make sure to consult an Application Engineer for the right size filter.
Filters also generally come with a clear polycarbonate bowl or a metal bowl to hold the condensate and/or contaminants. polycarbonate bowls can be damaged by some lubricants and chemicals therefore should have a metal bowl guard to protect people. Metal bowls provide much greater protection for applications of higher temperature, pressure and where chemicals may be present. If you are uncertain of the environmental conditions, a metal bowl is the best bet.
Keeping the filter bowls drained is important. EXAIR’s filters are automatic drain, which have a float mechanism to open a drain valve and release the liquid and contaminants. This keeps the filters low maintenance.
Since the filter elements trap contaminants, they will need to be changed as part of a regular maintenance program. Keeping the elements clean minimizes pressure drops in the compressed air system which keeps your end use application working properly. EXAIR also supplies replacement elements for all of our filters so we may assist in keeping your system running optimally.