Where Condensate Comes From
Moisture is a natural part of the compression process. Ambient air has some level of moisture in it already, and the compression process extracts it. Mechanically compressing air increases its heat and its pressure. The hotter air is, the more water it can hold. However, highly pressurized air can’t hold as much water vapor, so the excess water turns into condensation inside the system.
Equipment failure
As its internal parts wear out, an air compressor becomes more prone to moisture. It’s even worse if the system hasn’t been maintained correctly. Over time, the system loses the power and efficiency to extract water. At the same time, the compressor heats up more rapidly, allowing more moisture to build up.
Environmental factors
All air has moisture in it, and humid air has considerably more. If your compressor takes in that extra moisture, there will be more condensation within the machine. You can prevent this in several ways. First, move your compressors to a less humid area. If you have conditioned indoor spaces, use your compressors indoors. You can also use a refrigerated air dryer to reduce moisture. If you need a steam-free work environment, you can also use a desiccant air dryer.
An undersized unit and/or incorrect compressor type
If you’re straining your air compressor beyond its capacity, it will heat up more rapidly. This problem is more significant with piston compressors, which generate more heat when used for longer periods. You can combat this issue by investing in a larger air compressor or a separation system. A desiccant separator will remove the water from your compressed air.
How Condensate Affects Systems
Excess air compressor moisture can cause early failure of your compressor or your air-powered equipment. Some potential consequences are listed below
Rust and piping corrosion
Water, oxygen and metal components generally don’t mix. When the water builds up inside your air compressor, you can experience rust and corrosion inside the machine and pipes. Water in your air compressor can also cause hammer events, which you can identify by the knocking heard inside the piping.
Damage to pneumatic controls
Operations relying on pneumatic controls can’t afford moisture within their air compressors. Water in the compressed air supplied to pneumatic devices can cause rust, scale buildup and clogged orifices
Damaged circuits
Condensate and electricity don't mix. If the condensate gets into the electronics and electrical systems, it can cause corrosion, short circuit, arcing and fire, and even electrocution
Contamination
Water can ruin your lens and workpiece. For example, if you’re using an air-powered spray painter, water in the compressed air supply will mix with the paint and compromise the job.
Condensate Separation
there are various diy and ready-made systems to mitigate condensate in pneumatic systems, some better than others... you can make
Air Dryers
An air dryer is a separate device that works in conjunction with an air compressor to remove water vapor. You’ll find many types available for different applications. The four most common types of air dryers you can choose from are below.
Refrigerated dryers
The most used type of air dryer uses dual heat exchangers to cool hot air entering the compressor. Refrigerated dryers have many applications and are cost effective. They dry air to an appropriate level for most air uses.
Desiccant dryers
For highly moisture-sensitive environments, you can use a desiccant material, such as silica gel, molecular sieves or activated alumina, to absorb moisture from the air. They are often heatless, and heated versions will purge and regenerate the desiccant material. An oil-free compressor can even use the heat of a compression desiccant dryer, which heats the desiccant using the excess compressor heat.
Membrane dryers
Membrane dryers work as dehumidifiers, which lowers the dew point of air entering the compressor. They are as effective as desiccant dryers while requiring less maintenance.
Deliquescent dryers
One of the most basic air dryers, a deliquescent dryer, is low-maintenance and uses no electricity. They work using a pressure vessel and a dissolving tablet that absorbs water vapor. These dryers can also dry natural gas and landfill gas.
Moisture Traps
One of the simplest ways to filter out air compressor condensation is with a water trap combined with other filters. As the compressor takes in air through the inlet valve, the water trap bowl extracts moisture and sends it into a drain. After the water drains, the air passes through a filter to eliminate other impurities. This system can be an excellent choice for airbrushes and sanding tools, which require extremely dry air.
Piping System/Drip Leg
The most cost-efficient solution to moisture buildup is a piping system. In this configuration, tall, vertical metal pipes absorb heat to lower the air temperature. The water can then drop down to the bottom of the pipe, where it can be contained at drip legs within the piping. They’re an excellent option for office buildings and independent craftspeople powering air tools.
Condensate Disposal