Killer Condensation: Protect Automation Equipment by Lowering the Dew Point

The number one reason for automation equipment downtime stems from preventable excess water vapor and condensation. Corrosion, rust and pipe scale can detach and subsequently block air passages to reduce or halt equipment performance. Luckily, these extra vapors are easily removed with a well-maintained filtration system and lowering the dew point.

According to SMC Insider, “Drying compressed air at the highest pressure consistent with the facility’s demands will result in the most economical dryer operation. For most industrial applications, the rule is to first set the pressure dew point to meet general requirements, then adjust it 20 degrees F lower than the facility’s lowest ambient temperature.” This means that the dew point of each facility varies depending on application. Commonly, refrigerated dryers are used to lower dew point. The drying process eliminates condensation on cold pipes located in humid areas.

How do refrigerated dryers work? SMC Insider explains:

• Refrigerated dryer cools compressed air by removing heat at its inlet side and lowering its temperature dew point down to 37 degrees F
• Condensate is expelled through an automatic drain
• Dryer reheats dried compressed air back to ambient temperature using a heat exchange process

SMC also recommends that a “coalescing filter be installed upstream from the refrigerated dryer to remove any compressor oil and other contaminants….”

What are some alternatives to refrigerated dryers?

Membrane dryers are a cost-effective option for those applications where a refrigerated dryer is not ideal. Air easily passes through the membrane dryer as it is designed to capture only water and expel it outside. This process allows for continuous dehumidification. Membrane dryers are regularly used and recommended for pharmaceutical manufacturing, packaging and lab environments.

Another choice is desiccant dryers, which pass air through materials such as silica gel to absorb water vapors thereby taking the dew point temperature even lower than the abilities of refrigerated dryers. Using a coalescing filter to protect both the membrane and desiccant dryers from oils and excess water is strongly recommended for optimum efficiency and life.

How to Determine the Correct Factory Dew Point

Being off the mark in achieving the right dew point for an application can result in excessively high utility bills and maintenance costs due to water vapor damage. SMC Insider recommends drying the compressed air to a dew point “20 degrees F lower than the factory’s lowest ambient temperature then subdivide each compressed air supply by application using zone or point-of-use membrane or desiccant dryers to provide the appropriate level of dryness.” 

The fact that finding and maintaining the correct dew point can reduce downtime, increase energy efficiency, lower maintenance costs and protect against product defects makes determining the correct dew point and installing quality dryer equipment an excellent investment.