Types Of Compressed Air System Dryers

Many times, when discussing product selection with a customer, we commonly reference supplying as clean and dry air as possible to promote peak performance. In iron piping systems for example, when moisture is present, rust can develop which can reduce the performance of end use compressed air operated devices like air tools or cause issues on the exhaust side as you could exhaust unwanted mist onto a surface, like in a painting operation.

Example of a desiccant dryer

Typically, an efficient and properly installed industrial compressed air system will include some type of dryer to remove any moisture that may be present in the supply.

Let’s take a look at the various types of dryers available.

Refrigerant and desiccant dryers are two of the more commonly used types of dryers.

Refrigerant based systems have several stages. The compressed air first passes through an air to air heat exchanger  which initially cools the air. The air is then delivered to an air to refrigerant exchanger where an external source of liquid refrigerant further cools the air and sends it to a separator, where the water vapors condensate and are removed through a drain trap. Now that the air is dry, it is then cycled back to the air to air exchanger where it is heated back to ambient temperature and exits the system.

Desiccant dryers typically incorporate 2 tanks containing a porous desiccant which causes the moisture to sort of “cling” to the surface. In these systems, compressed air flows through one tank, while, using it’s own regeneration cycle, heated or unheated air is blown through the desiccant in the other tank to remove the moisture and dry the air.

Membrane Dryers are typically used at the end use product. These types of systems utilize membranes to dissipate water vapor as it passes through the material, while allowing a small amount of the dry air to travel the length of the membrane to sort of “wipe” the condensate and remove it from the system.

Deliquescent Dryers use a drying agent which absorbs any moisture in the air. As the vapors react with the desiccant, like salt, the desiccant liquefies and is able to be drained at the bottom of a tank. These are the least expensive dryers to purchase and maintain because they have no moving parts and require no power to run.

When a dryer is being considered for a particular setup, there are 3 common reference points used when determining the dryers rating – an inlet air temperature of 100°F, supply pressure of 100 PSIG and an ambient air temperature of 100°F. Changes in supply pressure or temperature could change the performance of a particular dryer. You want to follow the manufacturer’s recommendations when dealing with variances as they will typically provide some type of conversion.

For help with this or any other topics relating to the efficient use of compressed air, please give us a call, we’d be happy to help.

Justin Nicholl
Application Engineer
justinnicholl@exair.com
@EXAIR_JN

 

Heated Desiccant Dryers image courtesy of Compressor1 via creative commons license

Heavy Duty Line Vac Saves Backs and Shoulders!

Recently, I worked with a customer that was looking for a way to make a difficult job easier, reducing stress and strain on the body and preventing injury.  The customer was in the Environmental Services & Hazardous Waste Management area and regularly was called out to service acid neutralization tanks. These are commonly found in hospitals, laboratories, and schools, to neutralize lab wastewater before it is discharged to the sanitary sewer.  The systems typically utilize limestone chips to aid the in process.

Acid Neutralization Tank
                       Typical Acid Neutralization Tank Layout Sketch

Periodic maintenance includes the removal and disposal of the spent limestone chips, tank cleaning and replenishment with new limestone chips.  Some of the tanks are tall and narrow, making access to the limestone chips difficult, especially near the tank bottom. Current procedures involved small shovels and unnatural body positions to try to reach the bottom-most material.  A better way had to be found.

The customer came across the EXAIR website and found the Line Vac product line. After watching the demonstration video, he knew he had found his solution!  The Line Vac is a compressed air operated device that turns any hose or tube into a powerful in-line conveyor. Based on the height of the tanks and the size and weight of the limestone, we agreed the 2″ Heavy Duty Line Vac would provide the power and durability to empty the tanks in a timely manner, and safely and efficiently.  The customer would use a tow behind compressor so that a reliable source of compressed air would always be available.

hdlvkit (2)
Heavy Duty Line Vac Kit – Includes Auto Drain Filter Separator and Pressure Regulator

The Heavy Duty Line Vacs are available in sizes from 3/4″ up to 3″ in both smooth end and threaded connections for use with hose or pipe for conveyance.

To discuss your application and how an EXAIR Line Vac can make your transfer process easier and safer, feel free to contact EXAIR and myself or one of our other Application Engineers can help you determine the best solution.

Brian Bergmann
Application Engineer

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