subject: Finding The Right Air Dryer For Your Air Compressor [print this page] Pneumatics is a form of industrial technology that employs pressurized gas in order to do work. The jackhammer you hear being used to tear up the street outside your window is a pneumatic tool. So is the spray paint system used to apply the finish on your car and home appliances. Today, pneumatic systems power everything from dentist drills to sand blasters and they are a true modern marvel.
Pneumatic tools and machines rely upon air compressors to fill up a tank with compressed air -- in most cases, the very same air that we breathe. The problem with this is that common atmospheric gas (air) contains a lot of moisture in the form of water vapor. The more you compress the air, the more condensate you generate. Pneumatic equipment can be very sensitive to moisture contamination, and when water gets inside a compressed gas system it can wash contaminate lubricants put there to protect the compressor cylinders from wear. Some industrial grade pneumatic systems can collect as much as 18 gallons of liquids in the form of water vapor and contaminants in a day.
Removing unwanted water vapor from a closed pneumatic system requires an air dryer; something that can keep the humidity out of the machine so that it can't corrode the tools or spoil the work. To accomplish this, the industry employs compressed air dryers which are systems designed to take moisture and contaminates out of compressed air before it can harm the metal system.
There are three basic types of air dryers for air compressors. The most common type of these works by cooling down the air supply using refrigeration methods. When you reduce the temperature of air, water vapor in it condenses into liquid water where it can easily be drained away. Cooling hot compressed air is an extremely effective way to deal with the problem of water vapor in your lines, but the method can be energy intensive.
Another type of air compressor drying system works by passing compressed air through a pressure vessel containing an absorbent material such as silica gel which can trap water vapor and keep it out of the compressed air system. When this absorbent material is filled to capacity the vessel can be purged and reused. In some of these units two vessels are used so one can be purged of water while the other one collects it. These systems are known in the industry as desiccant dryers, and when you employ a dual vessel system, you can go a long time without any interruption.
The third variety of air compressor air drying technology uses a dehumidication membrane, which rids compressed air of water vapor as it is being produced. It uses a multiple-step process that begins by screening gases through a fine coalescing filter before sending it through some hollow fibers in the membrane bundle where the water vapor can finally be vented outside in the atmosphere. Membrane type air dryers are quiet, reliable and do not require any outside power source to operate. Many are designed for continuous 24 hour, 7 day a week operation where no maintenance is ever required outside the changing of cartridge or two every year.
