Static Electricity – What is it?

Now that the air is cooling and the humidity is dropping, you may often experience the phenomena of static electricity, and the resultant shock when touching something metal. As a child, you may have learned about static electricity by rubbing a balloon on your head and then seeing it stick to the wall. What is the science behind static electricity?

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All materials are made up of atoms, which have a positively charged core called the nucleus surrounded by a cloud of negatively charged electrons.  Each material is different, and in some types of materials the positive nucleus has a very strong pull on the electrons while in other materials the pull is very weak.  If we were to put a strong  pull material in contact with a weaker pull material, atoms from the weak pull material will migrate, and when the materials are separated, additional electrons will remain with the strong pull material.  Due to the overall increase in electron quantity, the material becomes negatively charged and the other material becomes positively charged. If the materials are rubbed together, the opportunities for the electron migration increases, and thus more electrons are exchanged.

Electrons build up more easily in dry conditions. When the air has humidity, static build up is less common because a very thin layer of water molecules coat most surfaces, which allows the electrons to move more freely and make most materials conductive and static free.

In some cases, static electricity can be a good thing – laser printers and photocopiers use static electricity to transfer ink from the drum to the paper.  Also, some power plants and chemical factories use static electricity  to remove pollutants in a process that takes place within the smokestack.

But generally when EXAIR gets involved, it is because the static electricity is causing an unwanted build up of static charge that affects a manufacturing process. The results of a static charge imbalance can result in a shock to an operator, materials sticking together, poor print quality, sensor or counter malfunctions, bad surface finish, or any number of other problems.

EXAIR offers systems for total static control, such as the Super Ion Air Knife and Ionizing Bars for wide applications such as paper, film and plastic webs, the Super Ion Air Wipe for narrow, continuously moving materials such as wire, tube, or extrusions.  Also offered are the handheld Ion Air Gun for use on three dimensional parts prior to assembly, packaging painting or finishing. Other options include the Ion Air Cannon for limited space or remote mounting applications, Ion Air Jet for tight spaces and concentrated airflow, and the Ionizing Point to provide close distance and accurate static removal.

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Super Ion Air Wipe

To discuss your static elimination concerns , feel free to contact EXAIR and one our  Application Engineers can help you determine the best solution.

Brian Bergmann
Application Engineer

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Spark Photo Credit – Eric Skiff – via Creative Commons License

Super Ion Air Wipe Used to Fix an Encoder

A wire manufacturer contacted me about a static problem that was occurring with their encoder. The customer explained the application problem involving an encoder used to measure the length of wire running through the process.  An encoder is an electromechanical device that can count segments of revolutions as it turns.  They had a small steel wheel attached to the encoder that would ride on a nylon coated wire.  As the wheel turned, the signal from the encoder calculates the length very accurately.  The issue with the steel wheel was slippage.  The friction between the steel wheel and the nylon coated wire was not high enough due to varying tensions.  The result was the length was not counted accurately, and with large spindles of wire, they were losing money.  To fix the problem, the wire manufacturer decided to change the wheel to a fabric type to increase friction.

8462 Super Ion Air Wipe
8462 Super Ion Air Wipe

They did solve their friction problem, but now the issue became a static problem. The two non-conductive (insulated wire and fabric wheel) materials started to generate enough static electricity that a spark would ground out against the encoder body.  The sparks have a high potential to damage the encoder or cause a false count.  Either way the customer knew he had to remove the static.  Once I understood the problem, I suggested the 2” Super Ion Air Wipe, model 8462.  It comes complete with the Super Ion Air Wipe, power supply, filter, and regulator.  It is designed to provide a uniform 360 degree ionized airstream directed conically to a continuous stream of material such as insulated wire.  With the proper mounting, the Super Ion Air Wipe would remove the static from entire area, the wire and the wheel.  This removed the static issue from the process and allowed the encoder to count correctly and accurately.

Static can become a real issue within processes like this, discharging to sensitive components and operators. If you run into issues with static in your process, no matter the shape, EXAIR has the product to help.  You can discuss your application with us by contacting one of our Application Engineers.

John Ball
Application Engineer
Email: johnball@exair.com
Twitter: @EXAIR_jb