Compressor Air Dryers: Understanding the Necessity of an Air Dryer

Using compressed air is an essential aspect and practice of numerous industries’ daily functions. Whether used in factory production machinery, food service appliances, or medical diagnostic equipment, air compressors are important production components for keeping businesses and organizations functioning.

Since compressors are working to squeeze more air molecules into a smaller space than atmospherically normal, the resulting pressure changes have side effects, namely condensation of water molecules. With a compressed air dryer in the system, the water and water vapor can be removed, helping the system to operate at peak performance.

Relative Humidity and Dew Point Temperature

Dew Point

In meteorology, the dew point refers to the temperature at which the air becomes fully saturated with water vapor. The air can only remain stable to the point of saturation. Once beyond that point, the water vapor begins to condense and forms liquid water. This happens as air is cooled, which we’ll circle back to soon.

Relative Humidity

Another meteorological term, relative humidity, describes how much water vapor is in the air versus how much water vapor can be contained. For instance, when the weather says 50% humidity, the air will only contain 50% of water vapor. If you have a 10 oz. glass, 50% humidity will only allow for 5 oz. to go in.

So, why does this matter for air compressors? As the air is compressed, the temperature changes, possibly reaching a dew point and a saturation point for relative humidity. In other words, when you compress air, you’ll make water also.

How to Determine When an Air Dryer is Needed for Your Air Compressor

An air dryer is probably a wise investment if you’re using compressed air often or have a sensitive manufacturing environment. If you’re not using one, though, and you’re wondering if you should, there are a few key signs to watch out for.

• Rust in pneumatic tools or around hose connections: If you see rust, you already have a problem. A build-up of water from repeated condensation in compressed air tanks and around hose fittings will compromise metal parts, including the integrity of the holding tanks.
• Liquid water is present: If water is seen leaking from hoses or lines, it’s a good bet there is water all through the system. Time to remedy the problem before experiencing the first problem listed.
• Tool exhaust sprays water vapor: Seeing small puffs or mini clouds when changing or using tools is another early warning sign to take notice of.
• Process equipment or tool manufacturers specify dry air only: Many process equipment manufacturers require dry compressed air for their equipment to function correctly.

These or other similar occurrences should all be reason enough to consider adding an air drying system. They are less expensive than replacing costly parts of processing and manufacturing equipment.

The Purpose and Functions of an Air Dryer

Air dryers for air compression systems more or less do exactly what they sound like they do. How an air dryer performs its task depends on the model or type used.

Refrigerated Dryers

One of the more common air dryers in industrial settings, the refrigerated dryer works to cool the air to its dew point, initiating condensation and then removing the excess water. Refrigerated dryers may not be as effective as other air dryers at removing all the moisture in the air. Refrigerated systems are excellent for systems that don’t require low dew point compressed air.

Desiccant Dryers

Desiccant dryers have two vessels filled with hygroscopic material that adsorbs water vapor. The two vessels alternate in drying the air and regenerating (removing the water vapor).

The towers alternate air contents and can be heated during regeneration to increase moisture extraction properties. Desiccant dryers often remove almost 100% of the moisture in the air system, which is ideal for high-purity applications.

Membrane Dryers

Using a semi-permeable membrane, this style of dryer separates water from the air, then ports the water out of the system. Membrane dryers are lower cost but are less efficient than desiccant dryers.

Deliquescent Dryers

In this system, the air is drawn through water-attracting material, usually a salt like potassium hydroxide or calcium chloride. Once the air passes the salts, water is pulled out of the air, attaches itself to the salts, then begins to drop and collect in the bottom of the air vessel.

What are the Benefits of Employing an Air Dryer?

Adding an air dryer to a compressed air system has many benefits, no matter the organization or industry.

Prevention of Water Contamination

Air systems must remain clean and clear when working with electronics, pharmaceutical materials, food services, high-powered lasers, or welding. Any contaminant or impedance may generate compounding or exponential issues with equipment and production timeframes.

Reduces the Water Build-up

Like water contamination, water build-up is moisture settling in areas of a compressed air system, which can negatively impact the functions, efficiency, or sensitivity of instruments, tools, or machines.

Minimizes the Corrosion

Corrosion happens from mixing oxygen and water when on the surface of the metal. As a chemical reaction takes place, the metal breaks down. Less water means less corrosion.

Halts the Freezing

If water is trapped in a compressed air system and the water freezes, the resulting expansion can damage or destroy equipment, tubes, and plastic pipes for compressed air. Freezing can also clog airways, impacting air flow and diminishing pneumatic power.

Increases the Effectiveness of Pneumatic or Air-powered Equipment

With a quality air drying system, lines stay clear, and air pressurization is efficient. Equally, the best possible air pressure keeps pneumatic machines and tools working properly.

Hinders the Growth of Bacteria

When water is left over time, bacterial growth can take over. Once bacteria are present in an air system, a complete purge and disinfection process is often necessary. Remove the moisture and reduce any possibility of mold and mildew growth.

The Best Air Dryer for You: How to Choose One?

Now that you’re sure you need an air dryer, how do you pick the best one? The most direct answer comes from assessing the conditions of each client’s shop, lab, workshop, or factory.

• Consider the industry. If the products or services of an industry call for completely dry air, your system will need to match the requirements. It’s also advisable to research what dryers other businesses or organizations in the industry use.
• Not too much and not too little. Some customers think that some are good, but more is better. Others are always looking to cut corners. In actuality, there should be a balance. 
• Equally, a medium-sized business probably doesn’t need a dryer for a large industrial factory setting. Matching the right air dryer for the compressor is a science. Consulting with a qualified professional is an excellent method for determining your system’s needs.
• Consider your average climate conditions. Currently, an area’s air temperature and humidity are considered and will affect the drying capabilities a system will need.
• Match the required dew point. Check what dew point is needed for the process or application. Choose the right dryer for the job.

What Makes Installing a Dryer for Your Compressor Necessary?

Like many questions about facility management and equipment maintenance, each organization will have unique requirements and needs, which only they can answer. Therefore, it’s important to consider what you’re using and needing the compressed air for. 

Consulting a professional with valuable experience and first-hand knowledge is an excellent method for shopping without committing. Ensure you’re getting the right components for your current applications and the organization’s or business’s future.

At Complete Engineered Solutions, air compressors and air dryers are our business. Let CES guide the process, whether looking for parts or services or installing a complete system.

Knowhow and Experience

Choosing to upgrade or outfit your operation can be a critical step in your business’s overall development and success. Selecting an air dryer for an air compression system improves system performance, reduces maintenance issues, and helps deliver client projects on time. With Complete Engineered Solutions, you’ll work with a team that capitalizes on years of experience, offering quality customer service. Our primary goals are resolving issues and satisfying the customer. Call us at (800) 701-3196 or contact us and see what we can do for you.