Entrainment: What is it?

By definition, entrainment is a form of the verb, entrain, which is fluid that is swept along into an existing moving flow.   Whenever there is a discussion about fluid dynamics, the Bernoulli’s equation generally comes up.  This equation is unique as it relates flow energy with kinetic energy and potential energy.  The formula was mainly linked to incompressible fluids, but under certain conditions, it can be significant for gas flows as well.  I would like to discuss how EXAIR uses the Bernoulli’s equation for entrainment to maximize efficiency within your compressed air system.

This relationship between pressure as compared to flow and velocity came to be known as the Bernoulli’s principle.  “In fluid dynamics, Bernoulli’s principle states that an increase in the speed of fluid occurs simultaneously with a decrease in static pressure or a decrease in the fluids potential energy”1. Bernoulli realized that the sum of kinetic energy, flow energy, and potential energy is a constant during steady flow.  He wrote the equation like this:

Equation 1:

P/r + V2/2 + gz = constant

P – Pressure

r – density

V – velocity

g – gravitational constant

z – height difference


Not to get too technical, but you can see the relationship between the velocity squared and the pressure from the equation above.  Being that this relationship is a constant along the streamline; when the velocity increases; the pressure has to come down.  An example of this is an airplane wing.  When the air velocity increases over the top of the wing, the pressure becomes less.  Thus, lift is created and the airplane flies.

Since we know the criteria to apply the Bernoulli’s equation with compressed air, let’s look at some EXAIR products.  Blowing compressed air to cool, clean, and dry, EXAIR can do it very efficiently as we use the Bernoulli’s principle to entrain the surrounding air.  Remember from the equation above, as the velocity increases, the pressure has to decrease.  When the pressure decreases, the surrounding air will move toward the low pressure.  That low pressure will sweep the ambient air into the air stream; called entrainment.

Compressed air is expensive, but the ambient air is free.  The more ambient air we can entrain, the more efficient the blowing device is.  As an example, we engineer the Super Air Knife to maximize this phenomenon to give an amplification ratio of 40:1. So, for every 1 part of compressed air, the Super Air Knife will bring into the air streamline 40 parts of ambient “free” air.  This makes the Super Air Knife one of the most efficient blowing devices on the market.  By adding mass to the flow stream, it will reduce the compressed air usage, saving you money, and allow for better cooling and a stronger blowing force.  For a drilled pipe, the amplification ratio is generally only two to three times.

We use this principle for many of our products like the Air Amplifiers, Safety Air Guns, Air Nozzles, Air Knives, and Gen4 Static Eliminators. Daniel Bernoulli was able to find a relationship between velocities and pressures, and EXAIR was able to use this to create efficient, safe, and effective compressed air products.  To find out how you can use this advantage to save compressed air in your processes, you can contact an Application Engineer at EXAIR.  We will be happy to help you.

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


  1. Wikipedia https://en.wikipedia.org/wiki/Bernoulli%27s_principle

Heavy Duty Line Vacs Within a Machining Facility

An overseas automotive company was using six machines that milled, stamped, and punched aluminum parts.  The machining center used two machines for stamping, and the piece of aluminum was 10mm X 10mm.  The second operation used two machines to punch out a 2mm diameter by 40mm rod. The last operation was milling the edges of the surface to a specific dimension.  The curly swarf that was being produced was around 5mm in diameter by 40mm in length.

Currently they had mechanical conveyors that would dump the scrap material into bins.  The operators would move the full bins to a central dumping area for recycling about 20 meters (66 feet) away.  They used shovels to move the scrap from the bins to a larger container.  This part of the operation took time and was ergonomically unsafe with lifting and twisting.   They were making about 300grams per minute, and with a 24-hour operation, that was a lot of material.  They contacted EXAIR to see if we could help them.

To move the aluminum scrap from the machines to the recycle container, they had to travel 20 meters (66 feet) horizontally, and 3 meters (10 feet) vertically above the floor.  For this distance and the size of the aluminum pieces, I recommended the EXAIR model 152200; 2” Heavy Duty Line Vac Kit.  The through opening for the 2” Line Vac was 44mm (1.75”) in order to move the material through.  This Line Vac is made from a hardened steel construction which is very resistant to wear.  It is also designed for higher vacuum levels to convey materials at a faster rate and longer distances.

The Line Vac is operated with only compressed air to generate a Venturi vacuum, and they are very compact and easy-to-use.  The vacuum generator does not have any motors or moving parts to wear, and the inline design makes it simple to attach a hose to the vacuum and exhaust side.  The kit includes a Filter Separator, Regulator and a bracket for cleaning, controlling and mounting.  They did have to add a hopper to each mechanical conveyor to collect the scrap.  Now, the Line Vac is connected to the hopper with a hose, and the scrap material would travel to the recycle container 20 meters (66 feet) away.

               The EXAIR Air Operated Conveyors, or Line Vacs™, are great tools for conveying items in a “scoop and shovel” type of applications.  If your company manually moves a product from point A to point B, you can contact an EXAIR Application Engineer to see if an Air Operated Conveyor could improve your process.  For this overseas customer above, the model 152200 Heavy Duty Line Vac Kit improved their operation and removed the ergonomic hazard for their operators.


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


Photo: Milling operation by gefrorene_wand  Pixabay License

EXAIR’s Static Eliminator Variety Provides Solutions for Any Industry

As the weather starts to change and the colder dryer months are upon us, static electricity can become a real nuisance.  Machines will start jamming, alignments will be difficult, dirt will collect to surfaces, and hazardous sparks can shock personnel.  EXAIR manufactures a line of Gen4 Static Eliminators, also called ionizers, to remove these nuisances.

Static is generated from non-conductive surfaces being “rubbed”.  This could be caused from going over rollers on a conveyor, stacking product onto each other, sheet feeding, and even peeling away a backing material.  When a non-conductive surface, or insulator, is moved or separated, electrons are “stripped” and redistribute into different areas on the surface.  Static charges are typically measured in kilovolts (KV), or 1,000 volts, and they can be either positive or negative in nature.

The higher the charge, the stronger the static force.  At a 10 KV static charge, a spark can jump one inch (25 mm) from the surface.   You probably felt that shock when working with plastic or non-conductive materials.  EXAIR has a Digital Static Meter to measure the amount of static voltage on a surface.  It is a great tool for finding problem areas in your process as well as determining the effectiveness of the treatment.

Static is dynamic.  The more you rub or move the material, the higher the static charges can form.  Static can also regenerate itself after the charges have been removed.  With higher static charges, the attraction force to other materials is much stronger.  This attraction could be to other products, dust, lint, and even you.  An undesirable effect of static can be seen with dirty surfaces, tearing, alignment, jamming and shock to personnel.  The EXAIR Gen4 Static Eliminators are engineered to remove both negative and positive static charges in an assortment of designs to best fit the application.

EXAIR manufactures nine different products, including Static Eliminators with air assistance to reach farther distances or Static Eliminators without air when surfaces could be disrupted by air flow. The newest product, the Intellistat™ Ion Air Gun is engineered for clean processes, laboratory and test environments.

The Gen4 ionizers are powered by a 5,000 Vac power supply.  The alternating current, AC, will create both negative ions and positive ions.  No matter the kind of static charge is on the surface, the Gen4 Static Eliminators will be able to remove it.  The power supplies come in either a 2 port or 4 port design; so, you can power multiple Gen4 Static Eliminators with one power supply.  The input power is selectable from either 115Vac or 230Vac in both 50/60 hz. An armored and electromagnetic shielded cable connects the power supply to the ionizer in a single wire design. This will help to protect the cable from abrasions, cuts and splits in industrial areas.

The Intellistat Ion Air Gun is powered with a 24Vdc power supply. The Gen4 Static Eliminators and the Intellistat Ion Air Gun have a shockless design, and they are UL Component Recognized and CE compliant.  I will give a brief description of each product that utilizes this rugged design for optimal static neutralization.

Gen4 Static Eliminators with Air:

Super Ion Air Knife
  1. Gen4 Super Ion Air Knife: This product has the best compressed air efficiency in removing static by combining the Super Air Knife with an Ionizing Bar.  The Gen4 Super Ion Air Knife has a 40:1 amplification ratio and uses the laminar air flow to carry the positive and negative ions to the surface.  The laminar flow allows for a quick static discharge in fast conveyance speeds.  They can also remove static from surfaces up to 20 feet (6.1 meters) away.  EXAIR manufactures stock lengths from 3” (76mm) to 108” (2.74 meters).  Some typical applications for the Gen4 Super Ion Air Knife are found in web cleaning, sheeters, pre-paint dust removal, and shrink wrappers.
  2. Gen4 Standard Ion Air Knife: Similar to the Gen4 Super Ion Air Knife, this product has a good compressed air efficiency.  It utilizes the Coanda effect to draw in ambient air at a 30:1 amplification ratio.  They come in stocked lengths from 3” (76mm) to 48” (1.22 meters).  The Gen4 Standard Ion Air Knife are used in similar applications as well as mold releasing, package cleaning, label applications and plastic bag opening.

    Gen4 Super Ion Air Wipe
  3. Gen4 Super Ion Air Wipe: This product blows ionized air in a 360-degree pattern.  They are engineered to remove static and debris from the outside of hoses, plastic pipe, extrusions, and coated wires.  With the split design, the Gen4 Super Ion Air Wipe can easily mount around the product without having to rethread.  They come in two different sizes with a 2” (51mm) and 4” (102mm) inner diameter. The ionized air has a fast static decay for speedy transfers.

    Gen4 Ion Air Cannon
  4. Gen4 Ion Air Cannon: Just like the name, this product will shower an area with ions to remove static. It can reach distances up to 15 feet (4.6 meters).  They are used in multiple areas including pre-paint car bodies, containers, shrink packaging, lenses, etc.  As an Air Amplifier, a small amount of compressed air will draw in a large amount of ambient air.  The ions are carried to the surface from the Gen4 Ion Air Cannon in a laminar air steam.   Once the ions coat the surface area, the air flow can gently remove any debris held by static forces.

    Gen4 Ion Air Gun
  5. Gen4 Ion Air Gun: For manual static removal to target specific areas, the Gen4 Ion Air Gun will work great.  This product comes standard with 10 feet (3 meters) of shielded cable for maximum reach.  An ergonomic air gun is attached to a Gen4 Ion Air Jet to manually remove static in difficult areas and from “shock” zones.  The Ion Air Guns work great for small batch processes used for quality checks or label applications.

    Ion Air Jet
  6. Gen4 Ion Air Jet: Similar to the Ion Air Gun, this product is used for “hands-free” operations. They use a small amount of compressed air to “shoot” the ions onto a surface.  They can be operated with a solenoid valve or foot pedal to blow ions during specific times and situations.  They can easily be attached to a Stay Set Hose and Magnetic Base for best “hands-free” positioning for optimal cleaning.  They work well on small targets for automated systems or inspections areas prior to packaging.
  7.  Intellistat™ Ion Air Gun: This is EXAIR’s newest product that is a lightweight solution for static and particle removal.  The patent-pending air gun comes complete with a 24Vdc power supply and a 6mm compressed air tubing.  There is a red and green LED lights to signify the production of ionized air for visual feedback.  The engineered air nozzles are quiet and OSHA safe.  The emitter point inside that creates the ions can be easily changed for replacement.  The applications range from circuit boards, electronic manufacturing, laboratories, clean rooms, and scientific testing.

The Gen4 Static Eliminators with air can be purchased with kits which will include the power supply (required for ionization), a filter (to clean contamination from the compressed air), and a regulator (to control the blowing force).  In the spirit of compressed air efficiency, EXAIR also offers the Electronic Flow Control, EFC, that uses a photoelectric sensor to turn on the air flow only when the product is under the Static Eliminator.

Gen4 Static Eliminators without Air:

Ionizing Bar
Low cost Ionizing Bars eliminate static cling.
  1. Gen4 Ionizing Bar: This rugged design is for industrial use to remove static cling from flat surfaces. They range from a length of 3” (76mm) to 108” (2.74 meters).  Without the assistance of air, the product has to be within 2 inches (51 mm) from the surface to remove static charges.  The Gen4 Ionizing Bar is shockless and works well in applications where blowing air could be a detriment for the process.  This would include screen printing, labeling, and large printing process.

    Gen4 Ionizing Points
  2. Gen4 Ionizing Point: This single point design is manufactured to remove static on small targets in tight spots.  Utilizing the same rugged design of the Gen4 Static Eliminators, this product can remove static in spot areas and help to stop jams in slitting operations. They can also be panel mounted to neutralize duct air.

If you find that static is creating process problems, wasting time, and costing you money, EXAIR has a large line of Static Eliminators that can help you.  For our U.S. and Canadian customers, we are offering a promotion for online orders for a limited time.  You will receive an AC Sensor, a $59.00 value, for free as a Promotional item from now until the end of March 2021 with a qualified purchase.  How can you not give them a try?  If you have an application, you can contact an Application Engineer at EXAIR to help select the correct model and remove that static nuisance.

John Ball
Application Engineer

Email: johnball@exair.com
Twitter: @EXAIR_jb

Solving a Static Electricity Problem when Applying Labels

Gen4 Static Eliminators

A company was applying labels to their plastic containers.  The labels were 4” (10cm) wide by 9” (23cm) long in size with a protective backing.  The backing material had to be removed prior to applying the label to a 9” (23cm) tall container.  With their label applicator, the label would wrap around the container.  They started to see misalignment and wrinkles in the labels when they were applied.  For the nonconforming parts, they had to remove the label and clean the surface to reapply another label.  This was time-consuming and a pain in the neck.  Since winter is here in the Northern Hemisphere, the drier air makes static very easy to create and will cause issues.  They contacted EXAIR to ask about our Gen4 Static Eliminators.

 With non-conductive materials like plastic and paper, static is easily generated; especially during cooler weather.  Static can be in a negative state or a positive state depending on the type of material.  With opposite charges, things are attracted to each other and will “stick” like magnets.  For similar charges, they will repel each other.  The higher the static charge, the stronger the force.  Static is generated from rubbing, hitting, and peeling which can cause electrons to be stripped from a surface.  For the customer above, the peeling away of the backing from the label caused the negative electrons to build on one surface.  And with the containers shifting, bumping and moving along the conveyor; static was also being generated.  Since like charges repel each other, the labels were not able to stay aligned and were creating bubbles on the surface.

When it comes to removing static, EXAIR is a leader in this market.  We have a large product line of different types of Static Eliminators.  Our design generates both positive and negative ions to remove any type of static charge up to 20 feet (6m) away.  In this application, I wanted to target two areas where static is present; the labels and the containers.  Since we could get close proximity to the label and the containers, I recommended using the Gen4 Ionizing Bars.  With a quick static decay rate, we can remove the static right before applying the label.  For this application, I recommended the model 8006 6” Gen4 Ionizing Bar and two model 8009 9” Gen4 Ionizing Bars.

EXAIR’s power supplies are what gives the Gen4 Ionizing Bars energy to create ions.  EXAIR offers two models of Gen4 Power Supplies; model 7960 which can power up to two Static Eliminator products and model 7961,  which can power up to four Static Eliminator products.  Since the Gen4 Ionizing Bars were mounted in the same area, the model 7961 Gen4 Power Supply was used to run three Ion Bars at once.  This helps to save money as they did not need to buy multiple power supplies.

Together, it was very easy to mount and start using.  The model 8006 was mounted right after the backing was removed from the label.  One model 8009 was positioned in the front of the container; and the second model 8009 was positioned in the back of the container.  Now they were able to remove all the static before the label was placed on the container.

EXAIR stocks lengths from 3” (76mm) up to 108” (2743mm), and we can ship a solution the same day.  When you are losing time and working hours due to static buildup like the company above, the Gen4 Static Eliminators can resolve it quickly and easily.

If you are having problems with static in alignment, jamming, contamination, or shocking staff; you can contact an Application Engineer at EXAIR.  The Gen4 Static Eliminators can remove the static and keep your process running smoothly.

John Ball
Application Engineer

Email: johnball@exair.com
Twitter: @EXAIR_jb