5 Best Air Compressor Water Separator & Filter Dryer

Compressed air always contains some water or moisture. Water in pneumatic lines damages air tools. Also, if you use compressed air for painting, separating the water is a must.

The best way to get rid of water from compressed air is to use an air compressor water separator filter. Hopefully, you will find a number of them from different manufacturers. But the selection of a proper one can be tricky.

A number of factors like, flow rate, pressure rating, and efficiency should be considered while selecting the best airline water separator.

Considering all these factors and evaluating a number of models from popular brands, we have come up with a list of the top five best air compressor water separators and filters. We hope this will help you find a proper one for your air compressor.

Flow Rate And Pressure Rating Comparison of Top Air Compressor Water Separator

Best Air Compressor Water Separators

1/2″ Particulate Filter Water Trap Separator by THB

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Specifications

  • Max Input Pressure: 215 PSI
  • Max Output Pressure: 150 PSI
  • Inlet and Outlet: ½ Inch NPT
  • CFM Rating: 105 CFM
  • Item Weight: 1.26 Pounds
  • Material: Metal & Polymer
  • Temperature Ratings: 41f – 140f
  • Poly Bowl Weight: 2.7 Oz

Overview

The first best water separator for air compressors in our list is the 1/2″ Water Trap Separator by THB. This filter will remove debris and liquid (water vapor) from your air compressor’s air. As this debris can affect the lifespan of the compressor, by removing them you get an extended life for your air compressor.

There is a Polycarbonate Bowl mounted on the filter. This filter is great for air compressor moisture removal process. You can view the moisture levels through it. Furthermore, there is a manual twist drain option for you to release the debris and liquid that is formed inside the system.

Aside from a water separator it also works as a filter for dirt, dust, and oil. This is why it is the best air compressor water separator for painting and other tasks.

3/8″ in Line Desiccant Air Dryer by Edge Industrial

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Specifications

  • Max Operating Pressure: 150 PSI
  • Inlet and Outlet: 3/8 Inch NPT
  • Material: Aluminum
  • Polycarbonate Bowl Weight: 5 Oz
  • Weight: 1.85 Pounds

Overview

One of the best air compressor filter dryers in our list is the 3/8″ in LINE Desiccant AIR Dryer by Edge Industrial. This is a desiccant air compressor water trap that removes moisture or condensate from your air compressor.

By doing so it not only expands the life of the compressor but also other pneumatic tools as well. You will get two bags of desiccant beads with this air dryer. The beads are initially blue but when they turn pink it indicates you have to change them.

You can dry the beads in a standard oven for three times. As a desiccant dryer, it will suck up all the moisture from your air compressor with the desiccant. This is why we are considering it as the best water trap for air compressor. 

3/4″ Heavy Duty Water Separator by THB

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Specifications

  • Max Operating Pressure: 175 PSI
  • Inlet and Outlet: ¾ Inch (Female NPT), 1/8 Inch (Male NPT)
  • CFM Rating: 140 CFM
  • Material: Aluminum Bowl
  • Weight: 1.6 Pounds
  • Metal Bowl Weight: 2.7 Oz
  • Temperature Rating: 41f to 140f

Overview

Here is another amazing THB filter regulator dryer. This one can remove water vapor and debris from any kind of compressor quite easily. By removing the vapor from the compressor’s air it extends the life span of your air compressor as the compressor stays safe from rusts.

This THB air dryer includes an auto drain system that will automatically drain away from the debris and moisture from the metal bowl. Aside from that, there is a wall mounting bracket and a sight glass mounted on the metal bowl. You can see the moisture level easily through the glass.

It not only removes the water vapor but also the compressed air filter protects your compressor from oil, dust, and dirt. Overall, this is one of the best air compressor water separators if you ask me.

PneumaticPlus SAU3030M-N03G-MEP Three Stage Air Drying System

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Specifications

  • Max Operating Pressure: 150 PSI
  • Weight: 2.9 Pounds
  • Size: 3/8 Inch NPT
  • SCFM Rating: 16 SCFM at 100 PSI

Overview

The PneumaticPlus SAU3030M-N03G-MEP is a bit different from out other water separators. It works in three stages. In the first stage, the air enters the particulate filter. Here corrosive moisture, rust, and dirt are removed from the compressor air.

Fine filtration takes place in the second stage. This means microscopic particles (as small as 3 microns) and oil aerosols (about 99%) are cleaned from the air. In the third and last stage, the air goes into a regulator, where the pressure is reduced to your desired pressure settings.

This is how this filter dryer works. As you can see it not only removes the unnecessary moisture but also reduces the dirt and the debris. This is why it is one of the best air compressor filter dryers to own.

3/4″ Air Compressor in Line Water Separator by THB

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Specifications

  • Max Operating Pressure: 250 PSI
  • Inlet and Outlet: ¾ Inch
  • CFM Rating: 185 CFM
  • Drain capacity: 300 ml
  • Weight: 4.23 Pounds

Overview

Our final choice for the best water separator is the ¾” in line air dryer for air compressor by THB. It is quite similar to the other THB water separator that we have here. Just like that one, this too includes a sight glass and a wall mounting bracket for checking the moisture level.

The only thing that differs is the CFM rating of the two water separators. The previous one had only 140 CFM whereas this one has a 185 CFM rating. Which means it allows more airflow at the same time than the previous one. Other than that both have the almost same build quality and performance.

How to Remove Moisture from Compressed Air?

The best way to remove moisture from compressed air is to use an air compressor water separator or filter dryer. They work more efficiently than any other method.

However, are several ways to remove moisture from compressed air. Here are a few techniques on how to keep water out of air compressor lines.

  • You can cool down the hot compressed air which will make the water vapor get condensed. When it happens you can easily separate the water from the air.
  • Another way is compressing the air with more pressure than you need for your compressor to work. After compressing the air-water will get separated. Then you have to let the air expand by reducing the pressure to the work level.
  • Membrane drying is a very good process of separating air and water vapor or moisture. Here selective permeation of the gas components is used to separate the vaporized water from the air.
  • You can use sulfuric acid or sodium chloride as absorption substances to absorb the water vapor or moisture from the air.
  • Finally, you can use the adsorption drying method. It involves the flow of moist air over a desiccant or hygroscopic material to make the air dry. Such materials are molecular sieves, silica gel, activated alumina, etc.

Frequently Asked Questions

Does my air compressor need a water separator?

Your air compressor will definitely need a water separator if there is a chance that your air tools will be damaged by water or moisture.

Again for some tools, there is a great chance that water or moisture will decrease efficiency.

Some specific jobs, like plasma cutting, painting requires water and moisture-free compressed air. In that case, using a water separator is a must.

If your air tools are made with iron and there is no protection layer in it, there is a great chance that water from the compressed air will cause rust in it.

In short, if you expect greater efficiency and longer life from your air tools, then you should use a water separator for your air compressor

How does an air compressor dryer work?

An air compressor dryer works by providing a high pressure on the air to make the moisture denser and turn it into water droplets while the air still remains in the gaseous state. After the droplets are formed, the dryer drains them out and release the pressure to purify the air.

Why do air compressors get water in them?

The air that a compressor takes in contains a lot of water vapor that is mixed with the air. It happens where there is more humidity. After getting into the compressor the water vapor begins to get denser because of the temperature change or the pressure or both.

Slowly the vapor becomes water droplets and these droplets harm the internal mechanism of the compressor in various ways. Not only water but also other dust and debris goes in the same way and they all add up to harm the compressor.

How many types of air dryers are there?

Air dryers are found in the following categories:

  1. Refrigerated drying units.
  2. Desiccant drying units.
  3. Heat-less.
  4. Heated.

The main thing that differs between each type of dryer is the agent that is placed inside to make the air dry.

What is a desiccant dryer?

In an air compressor, water vapor or moisture in the compressed air will lead to frozen air lines, corrosion, premature failure, and other operational problems. A desiccant air dryer is a tool, a system, or some kind of water traps for air lines, that you can use to purify compressed air. It does that by absorbing the moisture or the water vapor. A dessicant filter for compressor will provide air purification from -100°F PDP up to -40°F PDP.

What are the most common desiccant materials used in dryers?

The most common desiccant materials used in dryers are silica, activated charcoal, calcium sulfate, and calcium chloride.

What is a refrigerant dryer?

A refrigerant air dryer first refrigerates the compressed air. It then condenses the moisture to make water droplets. The droplets are then brought together to form bigger and heavier droplets.

There is an integrated moisture trap underneath the dryer. The bigger droplets are pulled down there by gravity. Finally, an automated drain is used to remove this moisture.

What is a membrane dryer?

Membrane dryers use a penetrable micro-tube technology. It is an efficient and unique way to remove moisture from the compressed air system. The membrane dryer lowers the dew point. When the dew point is lowered, water droplets are formed. These droplets can then be separated from the air easily. In short, it is an excellent air water separator. 

How do heatless desiccant dryers work?

This is an adsorption type dryer which provides down to a negative -100° dew point. Desiccant Dryers are commonly used in labs, hospitals, powder coating, and in electronics manufacturing. They are used in approximately 5% of compressed air installations. This type of dryer will use up to 20% of its capacity to regenerate the dryer media. This solution is employed many times as a point-of-use application because of this additional demand on the system.

I’m sure this article is enough for you to set up your mind on getting a water separator for your air compressor. To me, they are all the best air compressor water separators in one way or another. That’s why I added all five of them. But you can choose either one from this list according to your needs. My final tip for you would be to choose one very carefully as the performance of your compressor depends on such a small accessory like this.

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