Tag: contact

Contact Time: How to get the most from your EXAIR products

Published on by John BallLeave a comment
Poor Position vs Good Position

You may have heard us speak about contact time.  I would like to cover what that means in this blog.  Contact time refers to the amount of time that a target part is in the high-velocity airstream produced by an EXAIR blowing product.  The longer the contact time, the more effective the blow-off or cooling effect. Optimizing the mounting position of the EXAIR solution relative to the target makes a huge difference in effectiveness.  When our customers typically purchase EXAIR products, they have a tendency to improperly install them, reducing their performance capabilities.  Let’s look at a Super Air Knife.  In the photo above, you can see the relationship between a perpendicular and a recommended setup angle.  I have some recommendations that can help to increase the contact time and improve the performance. 

Super Air Knife Chamfer
  1. Angle – EXAIR machines a chamfer on the cap of the Super Air Knife as a starting point.  You want to have the chamfer parallel with the target line of movement.  This will create an air flow angle of about 45 degrees relative to the target.  This angle will increase the contact area and contact time, which is very beneficial for removing debris and/or heat.  Depending on the speed and height of the target, this can be altered for further refinement.
  2. Distance – For optimum performance, the Air Knife should be between 3″ (76 mm) to 12″ (305 mm) from the target.  If you are too close, the amplification ratio is sacrificed, and the force is reduced.  If you are too far, the air pattern will start to change, causing the velocity and force to decrease. 
  3. Counter-Flow – The direction of the air flow should be blowing in the direction opposite the target movement.  As an example, if the parts are moving from left to right, you want the Air Knife to blow from right to left.  This will allow the contamination to be blown back away from the cleaned surfaces, and it will increase the impact force to remove contamination, i.e. a head-on collision vs. a rear-end collision.

With these few simple steps, you will begin to maximize the performance and effectiveness of your EXAIR blowing solution.  Some accessories can help with the setup, like Swivel Fittings and Stay Set Hoses for the nozzles and the Universal Mounting Kit for the Air Knives.  You can modify the impact angle to best suit complex parts and systems.  If you need any help to get the most out of our products, you can contact an Application Engineer at EXAIR.  We will be happy to hear from you.     

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

The Generation of Static Electricity

Published on by John BallLeave 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 get this paper HERE and start removing static issues from within your plant or process.

In this blog, I would like to expand on the subject of how static can be generated.  On a molecular scale, the outer electrons that are orbiting the nucleus of an atom or molecule 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 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 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 easily.

Detachment

Detachment: When one material is separated from another by peeling, electrons may not be able to return to the original molecule.  Because of their larger surface areas, adhesive tape and protective films are common for generating static charges by detaching.  As an example; when the backing material is being removed from labels, the static will cause the labels to be misaligned or cause jams.

Friction

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 run over rollers.

Static tends to propagate.  The more contact, detachment, and friction that occurs, the higher the static charge.  Even after the static charge is removed from the surface, it can regenerate using the same mechanisms described 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 electricity 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. 

EXAIR manufactures a large line of Gen4 Static Eliminators to remove this static nuisance.  From now until March 31st, 2024, EXAIR will be giving away a free AC Sensor, a $76.00 value, as a promotional item with a qualified purchase of the Gen4 Static Eliminators.  If you would like to discuss your application and potential static issues, you can contact an Application Engineer at EXAIR.  We will be happy to help.

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

Generation of Static Electricity

Published on by John BallLeave 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 get this paper HERE and start removing static issues in your plant or process.

In this blog, I would like to expand on the subject of 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 positively charged static.  With non-conductive materials like plastic, paper, rubber, glass, etc., once dislodged the electrons cannot move back to the original atom without subsequent intervention. There are three common methods of static generation that will cause this phenomenon to occur.  I will explain each one in brief detail below:

1 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 easily.

2 Friction: 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.   For 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 become, allowing the balloon to “stick” to another non-conductive surface.  For example, within an industrial application, friction type static generation is also observed when sheets of material are stacked, sliding across one another as they move into place.

3 Detachment:  When one material is separated from another by peeling, electrons generally do not return to the original molecule.  Because of their larger surface areas, adhesive tape and protective films are common for generating static charges through the detachment method.  For example; when the backing material is being removed from labels, the static will cause the labels to be misaligned or cause jams within the rollers and guides in a machine.

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

Another variable that exacerbates 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 electricity 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. 

Gen4 Static Eliminators

EXAIR manufactures Gen4 Static Eliminators to remove all static nuisance that may likely be plaguing your processes.  Beginning January 1st, 2024, EXAIR will be giving away a free AC Sensor, a $76.00 value, as a promotional item with a qualified purchase of the Gen4 Static Eliminators.  If you would like to discuss your application and potential static issues, you can contact an Application Engineer at EXAIR.  We will be happy to help.

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

Three Ways Static Electricity is Generated

Published on by John BallLeave 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. Download it now by clicking this Link, and begin to remove the static issues in your plant or processes.

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 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 charges.  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
Application Engineer
Email: johnball@exair.com
Twitter: @EXAIR_jb