We have mentioned here on the EXAIR Blog numerous times just how bad static can get in cooler, dryer regions with low humidity. The amount of moisture in the air is expressed as relative humidity. This value is given as a percentage of water vapor in the air, compared to how much it could hold at that temperature. In conditions of lower relative humidity, static charges build up much easier. When the relative humidity is high, there’s a higher concentration of water molecules present in the air. These water molecules “coat” the surface of the material, allowing electrons to move more freely and form a layer over the material. This layer of water molecules acts like a lubricant, reducing the forces that cause static to generate. There are many applications that static may only pose an issue once the climate changes.
This could lead one to deduce that tropical climates don’t experience static, given the high humidity present in these areas. While it may be LESS common to experience static troubles in humid conditions, it’s far from impossible.
Such was the case during my recent visit with our partners in Costa Rica. A client of theirs that handles a variety of extruded PVC pipes and shapes was having some problems with a printing process. In their line, after the pipes are extruded, they must mark a batch code and company name on the outside of the pipe. On some days the residual static charge is so high that the ink won’t properly adhere to the outside of the pipes.
A process that should be automatic was requiring them to station an operator nearby to keep an eye on the printer. When issues arise, they must stop production, clean the marking off, and run it back through again. They don’t have the man-power to allocate a person to stand there and monitor things continuously, so this has led to some batches going out marked wrong and leading to rejection and subsequent return.
Fortunately, EXAIR has a wide variety of products designed specifically for use in treating industrial static problems. After checking out the application, it was clear that one of our Ion Air Jets was going to provide a great solution for the customer. Since the specific location of the marking varies depending on the diameter of pipe, they needed something that could also be adjusted. I recommended our Stay Set Ion Air Jet to be installed just prior to the printing head and directed onto the pipe where we’re to apply the marking.
After installation, they continued to monitor closely for a few shifts and managed to make it through a complete day without any rejected material. They no longer have a need to monitor this step in the process and can free up personnel for more important tasks in the facility.
As winter draws to a close, don’t assume static will just automatically go away when the warmer temperatures of spring and summer arrive. In some cases, as was in this application, static can be present despite humid conditions.
Tyler Daniel, CCASS
Application Engineer
E-mail: TylerDaniel@EXAIR.com
Twitter: @EXAIR_TD
