Tag: static removal

Static Electricity and How it is Generated

Published on by johnball2014Leave a comment

EXAIR published a white paper, Basics of Static Electricity, explaining what causes static electricity; how it is generated; and steps to eliminate it. You can download this paper HERE, and begin to remove the static issues in your plant or process.

In this blog, I would like to expand on the subject about how static can be generated.  On a molecular scale, the outer electrons that are orbiting the nucleus can be “stripped” and redistributed from one atom to another.  This will cause an electrical charge imbalance called static.  An additional electron will create negatively charged static while atoms losing an electron will create a positively charged static.  With non-conductive materials like plastic, paper, rubber, glass, etc., the electrons cannot move back to the original atom. There are three common methods of static generation that will cause this phenomenon to occur.  I will explain each one in a brief detail below:

Contact

Contact – Whenever objects hit each other, electrons can be passed to or received from the surface of another object. The number of electrons being transferred is based on the type of triboelectric material.  But, with plastic bottles or trays bumping into each other on conveyor belts, static can be generated relatively easy.

Detachment

Detachment – when one material is being separated from another material by peeling, electrons may not able to return back to the original molecule. Adhesive tape and protective films are prevalent in generating static charges by detachment because of the larger surface areas.  As an example; when the backing material is being removed from labels, the static will cause the labels to be misaligned or cause jams.

Frictional – This is one of the most common reasons for generating large static forces. It is caused by two non-conductive surfaces being rubbed together.  The amount of force being applied to the material as it slides back and forth will create higher static charges.   As an example, it is noticed when you rub a balloon on your hair.  The more times that you rub the balloon against your hair, the stronger the static forces, allowing the balloon to “stick” to the wall.  It is also noticed as sheets of material are stacked or running over rollers.

Static tends to propagate.  The more contact, detachment, and friction that occurs; the higher the static charge.  Even when the static is removed from the surface, static charges can still regenerate by the same mechanisms above.  So, controlling the static can be determined by the type of treatment as well as the location for removal.

Another variable that affects static generation is humidity.  Most process problems are noticed during the winter months as the ambient air is drier.  With a lower relative humidity, static can develop easier and with greater strength.  We always refer to winter as static season.  You may even notice this when you walk across the carpet and get zapped by touching a door handle. 

Production problems can occur like dirty surfaces, tearing, alignment, jamming and shock to staff with static.  EXAIR has a number of Static Eliminators to remove these process snags that can cost your company money.  You can contact an Application Engineer at EXAIR to discuss any static issues that are occurring.

John Ball
International Application Engineer


Email: johnball@exair.com
Twitter: @EXAIR_jb

Quantify the Static Charge in Your Processes w/ EXAIR’s Static Meter!

Published on by Tyler DanielLeave a comment
Static Eliminators

In a recent blog post, I discussed the theory behind how static is generated (if you missed it, check it out here!!). One of the troublesome aspects about static electricity is that it’s hard to measure. The static charge on the surface of a part is not visible, that is unless the charge is high enough to result in a static discharge to nearby equipment or personnel. In most cases, issues related to static aren’t always 100% clear and are impossible to measure without the right equipment. So how do we measure static?

It’s actually simple: EXAIR’s Model 7905 Static Meter is designed to take the guesswork out of the equation when evaluating static charges. It allows for an easy one-hand measurement of the static charge on the surface. This allows you to measure in numerous places in the process to evaluate the true source of the static. In most cases, the highest voltage reading will indicate the source of your static problem.

The 7905 Static Meter is sensitive and responsive, indicating the surface voltage and polarity on objects up to +/- 20kV when measured at 1” from the surface! On the front face of the meter is a hold button, a battery indicator, and a “zero” button to zero out the instrument and ensure an accuracy of +/- 5% of the reading when 1” from the charged surface.

When looking for a method to identify the source of your static woes, EXAIR’s Static Meter is an ideal fit. Since the method used to neutralize this static is also invisible, using a Static Meter in conjunction with any EXAIR Static Eliminator allows you to confirm and quantify the result of the products working as intended. To do this, simply take a measurement of the surface before and after treatment with any EXAIR Static Eliminator. After being exposed to the static neutralizing ions, the residual static charge should be neutralized and able to be confirmed on the display of the Static Meter. For customers and applications that require it, EXAIR also offers an ISO 17025 Accredited Calibration service.

The Static Meter is the only device that will allow you to identify and quantify any static charge. Don’t continue to let static charges wreak havoc in your processes, we have them available to ship today from stock alongside all of our cataloged Static Eliminators!!!

Tyler Daniel, CCASS

Application Engineer/International Trade

E-mail: TylerDaniel@EXAIR.com

Twitter: @EXAIR_TD

Intelligent Compressed Air: Static Electron Theory

Published on by Tyler DanielLeave a comment

Did you know that the discharge you’ve likely felt on a cold winter day after walking across a carpeted surface and touching a door knob is a result of static electricity? To understand how this static electricity is generated, let’s first go back to basic chemistry class and talk about the atomic structure of an atom.

An atom consists of three basic particles: protons, neutrons, and electrons. The protons (positively charged) and neutrons (neutral charge) form the nucleus. Outside the nucleus, electrons (negatively charged) are quickly zipping around in orbits at specific distances from the nucleus. These electrons are bound to the nucleus due to electromagnetic force. Opposite charges attract, since the protons in the nucleus carry a positive charge this acts on the negative charge of the electrons and keeps them in orbit. The closer the electron to the nucleus, the stronger the bond and the more energy required to break that electron from its original orbit.

When an atom gains or loses an electron, it affects the balance that occurs within an atom. If an atom gains an electron, it now has more electrons than protons. This results in a negatively charged atom. The opposite can be said if an atom loses an electron, it now carries a positive charge. This charge imbalance is where static electricity comes from. Both positive and negative charges will remain statically charged until contacted by or comes into close proximity to a conductive or grounded surface.

The strength of this charge will depend on a few different factors: the types of materials, surface area, environmental conditions, etc. will all play a role in the generation of a static charge. The triboelectric series is a scale, listing various different materials and their tendency to become positive or negative. Those at the far end of the spectrum have an increased propensity to gain or lose an electron, while those in the center are more likely to remain balanced. When two materials on opposite ends of the spectrum come into contact with one another, it poses the greatest risk of generating high levels of static electricity. The chart below shows some common materials and where they fall on the tribolectric series.

When materials carry a static charge, a variety of problems can ensue during manufacturing. These can manifest in the form of painful shocks to operators, materials jamming or tearing, sheet feeding problems, discharges causing imperfections in the material appearance, etc. To remove the charge, we need to introduce static eliminating ions to balance out the charge on the material. EXAIR’s line of Static Eliminators create an equal number of both positive and negative ions to saturate the surface of the material and neutralize any charge present.

With a wide range of different solutions all available from stock, EXAIR has the solution to your static problems this winter. Give us a call and we’ll be happy to discuss the application and help to identify the best method to mitigating any static issues in your processes. Take advantage of EXAIR’s current promotion (now through the end of March) and receive a free AC Sensor with your Static Eliminator purchase!

Tyler Daniel, CCASS

Application Engineer
E-mail: TylerDaniel@exair.com
Twitter: @EXAIR_TD

Atom photo courtesy of janjf93 via Pixabay Creative Commons License

Gen4 Ion Air Cannon Explained

Published on by Brian FarnoLeave a comment

When larger areas need to be covered with an ionized air stream and the surfaces needing to be covered are not flat, then an array of Gen4 Ion Air Cannons can often be the solution. This is something that the automotive industry as well as many others have been using since before I have been a part of the EXAIR team. So just how does the Gen4 Ion Air Cannon achieve this?

At its core, the Gen4 IAC is designed around a 2″ Super Air Amplifier, and then we add ionization and a stand. The largest benefit to this is the ability of the Super Air Amplifier to entrain large volumes of free ambient air while using small amounts of compressed air. By entraining large volumes of free ambient air and then directing it down through the throat of the IAC and ionizing it upon exit of the barrel, we maximize the potential to eliminate static on the target surfaces and provide a good blowoff at the same time. To give a visualization of the performance, check out the video below.

When adding ionization to this airstream, complex shapes can easily have static elimination as they are being conveyed. Take an automotive body for example, as it travels down the assembly line, before paint or primer, they get blown off to ensure any debris from the facility is removed before they are coated. An array of Ion Air Cannons can be installed at a distance from the surface to fit multiple vehicle models and still target the entire surface needed.

Three Gen4 Ion Air Cannons are used to blow off the debris and remove unwanted static charge from a primer vehicle body before painting.

By arranging the blow-offs to utilize the large volume of ambient air entrained and direct the airflow at an angle in which once it hits the surface, it expands in the direction needed to remove the debris it is easy to cover irregular shapes. The setup shown above will utilize 15.5 SCFM per IAC when operated at 80 psig and give a forceful blast to remove any debris on the surface; the total consumption would be 45.5 SCFM at 80 psig to remove all debris from the top surfaces of this vehicle body before it goes into the final paint area. A centrally located 4 port Gen4 Power Supply, model 7961, can simplify cabling and installation while powering all three Ion Air Cannons. To optimize compressed air usage, an Electronic Flow Control can easily be installed to shut the air off whenever a car is not present; adding something like this ionized blowoff station to existing equipment is easier.

If you would like to discuss what the Gen4 Ion Air Cannon kit or any of our point-of-use engineered compressed air products can do for you in your facility, please contact an Application Engineer today.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF