Compressed Air Wet Receivers and Condensate Drains: Keeping your Systems Running Clean and Efficient

Compressed air systems are the backbone of countless industries and operations, from powering tools to cleaning, cooling and drying products in process. But behind the scenes, components like the wet receiver and condensate drain play pivotal roles in ensuring these systems deliver clean, reliable air. If you’re involved in facility management, maintenance, or just curious about how compressed air systems tick, understanding these elements can make all the difference. Let’s break it down!

What is a Wet Receiver in Compressed Air Systems?

In a compressed air setup, a receiver is a storage tank that holds pressurized air after it’s been compressed but before it’s distributed to the point of use. A wet receiver, specifically, is positioned downstream of the compressor but before the air dryer or major filtration stages. This means it stores “wet” compressed air—air that still contains moisture, oil, and other contaminants picked up during compression.

The “wet” designation comes from the fact that the air hasn’t been treated yet. As air is compressed, it heats up, and when it cools in the receiver, moisture condenses into liquid water. The wet receiver acts as a buffer, smoothing out pressure fluctuations and giving that moisture a place to settle before the compressed air moves further down the line. Think of it as a staging area that helps protect downstream equipment from surges and contaminants.

Condensate Drain

As air cools in the wet receiver, water vapor turns into liquid condensate—often mixed with traces of oil and dirt. If this condensate isn’t removed, it can corrode the receiver, clog pipes, or damage tools and equipment downstream. The condensate drain is the unsung hero that gets rid of this unwanted liquid.

Typically mounted at the bottom of the wet receiver , the drain can be manual, automatic, or timer-based:

  • Manual drains require someone to open a valve periodically.
  • Automatic float drains open when enough liquid accumulates.
  • Electronic timer drains release condensate at set intervals.

No matter the type, the goal is the same: keep the system dry and free of buildup.

A well-maintained wet receiver and condensate drain mean cleaner air, longer equipment life, and lower operating costs. Wet air can cut tool efficiency by 20% or more, while corrosion from neglected condensate can force early replacements for all downstream equipment. On the flip side, a little attention to these components keeps your compressed air system humming—and your bottom line happy.

Next time you hear the hiss of a pneumatic tool or the hum of a compressor, think about the wet receiver and condensate drain. They’re not flashy, but they’re indispensable.

Jordan Shouse
Application Engineer

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Photo: Blue Air Receiver Attribution – CC BY-ND 2.0

Dryers On A New Level – Deliquescent Level Even.

Today I want to discuss dryers and not the type that I have repaired many times due to having three kids in my house. Speaking of which, the amount of hair that gets trapped within a dryer is one of the things my nightmares are made from. You’d think we have a Yeti living in our home. While the picture below is of our first dryer and washer, that platform has been repurposed into a workbench and the metals have all been recycled back into something else now. That’s not what we are here to talk about. Instead, we are going to discuss deliquescent dryers.

Deliquescent dryers can sometimes be confusing. Some compressed air dryer vendors use the terms deliquescent and desiccant synonymously, as if they were interchangeable in describing their equipment. Deliquescent dryers are not complex drying systems and are most commonly found in the petrochemical industry.

Deliquescent Dryer

Unlike any other dryer, a deliquescent dryer is also used to reduce or remove moisture before it turns to liquid water. These dryers can be installed indoors, outdoors, offshore, or in any remote location. They do not require electricity for operational purposes or have any moving parts, making them easy to maintain and economically more efficient. In a deliquescent dryer, moist air (gas) passes over a layer of deliquescent tablets that absorb moisture. The pressure dew point lowers as the tablets slowly dissolve, the condensation falls into the drain area, and the drier air flows through the outlet into the piping system.

The best deliquescent materials are salts due to their strong attraction to moisture. Deliquescent desiccants (drying tablets) are formulated from calcium chloride, magnesium chloride, potassium chloride, and lithium chloride. Not all deliquescent desiccants are equal. The final formulation and properties of the desiccant can significantly impact the design of a dryer tank. That is, the surface of the desiccant chemical, often beads or pellets, will liquefy, and the resulting liquid will flow to the bottom of the vessel. There is either a drain (manual or auto) at the base of the deliquescent dryer which is used to expel the collected fluid.

Some factors that will affect the consumption of the desiccant are the type of adsorbent, type of adsorbate, the size of the adsorbent bead or pellet, the concentration of the adsorbate in the compressed air stream, and the temperature of that air stream.

You will want to have a water trap, also known as a general-purpose compressed air filter, plumbed in line just upstream from the deliquescent dryer. Otherwise, any liquid water flowing with the compressed air into the air dryer will make short work of the desiccant chemical, requiring a more frequent—and expensive—recharge.

Compressing air generates heat. That hot, moist compressed air will consume the desiccant chemical in the deliquescent dryer much more quickly. The best practice is to ensure the airflow to the dryer is as cool as possible, with a long airline and a dwell tank before the deliquescent dryer, to allow the air to cool and have water saturate out naturally.

A deliquescent dryer can be expected to reduce the compressed air dew point by 20 – 30 deg. F, or so. The degree of drying depends how saturated the airflow is going in and on the type of deliquescent chemical used.

Unlike other forms of compressed air dryers, a deliquescent unit doesn’t guarantee the air will reach a certain dew point. The amount of water vapor in the air that exits the dryer is completely predicated on how much water vapor is in the air going into the dryer.

Brian Farno, MBA – CCASS Application Engineer

BrianFarno@EXAIR.com
@EXAIR_BF

Double Dare, Double Dragon, Double Mint Gum

1 -Classic Double Dragon Arcade Game from 1987! Spike & Hammer Save The World – This is the game I used to dump quarters in every visit to the mall.

It’s no secret, I’m a kid of the 80s. If you remember any of the three items in the title of this blog, then we may be able to be friends still, and I want to ask a question. How’s your sourdough starter doing? Okay, you got me, the blog isn’t going to be about sourdough, or one of my favorite TV shows from growing up, or the video game I always threw quarters into when we were allowed to spend some money at an arcade, but it’s going to be about Double Acting Reciprocating Air Compressors.

You may have heard from us about the many types of compressors before, and we would just like to make sure we have shared a few different viewpoints on these topics. The double acting compressor is a piston action compressor. Unlike the single action compressor, these will actually build pressure above and below the piston for each rise and fall, rather than just the rise. Because this generates twice as much air, these are generally found in larger sizes than the single acting compressors. This also means the compressor is constantly pushing a load out of the system whenever the motor is turning. While they do put more volume out and work with both directions of the piston, they have been found to only be around 32% more efficient than their single acting counterpart. Nonetheless, they are available in sizes that can supply an entire manufacturing facility and can be used efficiently when placed into a system that is designed correctly.

If you want to learn about more types of compressors, need help with your Konami cheat code, or what to discuss a point of use compressed air application, give us a call, chat, or email.

Brian Farno, MBA – CCASS Application Engineer

BrianFarno@EXAIR.com
@EXAIR_BF

1 – Classic Double Dragon Arcade Game from 1987! Spike & Hammer Save The World – Joe’s Classic Video Games – retrieved from – https://www.youtube.com/watch?v=_SqYOHpUiDM

Compressed Air Dryers : What are they Good For?

Absolutely Nothing….. err ALOT! They are really good for a lot! Specifically removing moisture/condensate from compressed air.

In almost every operation, clean, dry compressed air will result in lower operating costs. The purpose of compressed air dryers is to overcome the dew point of your compressed air by removing water from it. Compressed air can contain humidity, and in the right environments it can reach the dew point temperature and condense into a damaging liquid. This liquid can be problematic, as it can contaminate your products or equipment, causing frozen pipes, and possibly leading to corrosion and other issues.

Now that we know how important they are how do you know which one is right for you?

Types of compressed air Dryers

Refrigerant Dryer – the most commonly used type, the air is cooled in an air-to-refrigerant heat exchanger. (Here is a great blog deep diving on Refrigerant Dryers)
Regenerative-Desiccant Type – use a porous desiccant that adsorbs (adsorb means the moisture adheres to the desiccant, the desiccant does not change, and the moisture can then be driven off during a regeneration process). (Here is a great blog deep diving on Desiccant Dryers)
Deliquescent Type – use a hygroscopic desiccant medium that absorbs (as opposed to adsorbs) moisture. The desiccant is dissolved into the liquid that is drawn out. Desiccant is used up and needs to be replaced periodically. (Here is a great blog deep diving on Deliquescent Dryers)
Membrane Type– use special membranes that allow the water vapor to pass through faster than the dry air, reducing the amount of water vapor in the air stream. (Here is a great blog deep diving on Membrane Dryers)

The selection of an air dryer is done best by the professional who knows or learns the particular end uses, the amount of moisture which each use can tolerate and the amount of moisture which needs to be removed to achieve this level. Air, which may be considered dry for one application, may not be dry enough for another. Dryness is relative. Even the desert has moisture. There is always some moisture present in a compressed air system regardless of the degree of drying.

For compressed air, the best way to specify dryness is to cite a desired pressure dew point. Different types of dryers, therefore, are available with varying degrees of pressure dew point performance. To specify dew point lower than required for an application is not good engineering practice. (Naming a pressure dew point is how to state the degree of dryness wanted.) It may result in more costly equipment and greater operating expense.

If you have questions about compressed air systems and dryers or any of our 15 different Intelligent Compressed Air® Product lines, feel free to contact EXAIR, and I or any of our Application Engineers can help you determine the best solution.

Jordan Shouse
Application Engineer

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Find us on the Web 
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Twitter: @EXAIR_JS