One word I don’t think I ever used before I started working at EXAIR is entrainment. It was not a concept that I had ever needed to think about or discuss. But now, having worked here for a short while, it is a topic that I discuss regularly – daily even. Many of EXAIR’s quiet and efficient compressed air products are designed to maximize air entrainment.
Entrainment is defined in the simplest of terms as: to draw in and transport (something, such as solid particles or gas) by the flow of a fluid. In the context of EXAIR’s compressed air products, the surrounding ambient air is entrained by the primary air flow created by the compressed air.
For example, when compressed air exits the precise slotted nozzle of our Super Air Knife, a low pressure area is induced, which speeds up and draws in ambient air. This air entrainment (at a ratio of 40:1) is what makes our Super Air Knives so efficient. This same effect is true for our Super Air Amplifiers, Super Air Nozzles, Super Air Wipes, as well as many other products.
This effect was first described by Daniel Bernoulli in his book Hydrodynamica, where he first explained what we know as Bernoulli’s Principle. His principle states that an increase in the speed of a fluid occurs simultaneously with a decrease in pressure. This is derived from the conservation of energy, where an increase in kinetic energy (speed) requires a corresponding reduction in potential energy (pressure).
Daniel Bernoulli was an interesting man, who we have written several blogs about, like this one here. But in summary, the work he did in the 1700s is fundamental to our products. If you would like to discuss your application, and how the Bernoulli Principle may be beneficial, feel free to give us a call!
Because of the large amount of energy required to run an air compressor, the pneumatic system is considered the fourth utility in a manufacturing plant. And saving this commodity and using it as efficiently as you can, should be a priority. EXAIR has many products that can save energy by using less compressed air. And the story behind this is entrainment explained by Bernoulli’s equation.
Bernoulli’s principle explains how a high velocity fluid can generate a low pressure. (You can read more about Bernoulli’s principle HERE.) Let’s start by looking at Equation 1.
Equation 1:
P + d * V2/2 = C
P – pressure
d – density of the fluid
V – velocity
C – a constant
As you can see from Equation 1, when the velocity goes up, the pressure must go down. When we have a lower pressure, then the surrounding fluid will fill that void. Since air is a fluid, we can use high velocity to entrain the surrounding ambient air. The free air will add to the compressed air to give the airstream mass for a hard-hitting force. This ratio of ambient air to compressed air is called entrainment. The higher the entrainment, the more efficient the product. Bernoulli’s Principle can be applied in two ways; as a Coanda and as a Venturi. EXAIR uses both methods in our products for creating low-pressure effects.
Compressed air flows through the inlet (1) to the Full Flow (left) or Standard (right) Air Knife, into the internal plenum. It then discharges through a thin gap (2), adhering to the Coanda profile (3) which directs it down the face of the Air Knife. The precision engineered & finished surfaces optimize entrainment of air (4) from the surrounding environment.
The first way is from a Coanda profile. Coanda, named after Henri Coanda, noticed that a fluid would “hug” a curved surface. (You can read more about Henri Coanda HERE.) The high velocity air going around the curved surface will generate a low pressure above it. You can imagine an airplane wing generating that low pressure to fly. We use this with our FullFlow and Standard Air Knives, our Air Wipes, and our Air Amplifiers. With a Coanda profile, we can get an amplification ratio up to 30:1, which means that for every 1 part of compressed air, 30 parts of ambient air is entrained. We are able to create an efficient blow-off device by using the Coada profile.
To generate even lower pressure, this can be done by a Venturi. This phenomenon is named after Giovanni Venturi, who discovered that by increasing the velocity through an orifice, the surrounding fluid will move with it, generating a lower pressure. (You can read more about Giovanni Venturi HERE.) Remember the higher the velocity, the lower the pressure from Equation 1 above. We use the Venturi effect on our Super Air Knives, E-Vacs, Line Vacs, and Super Air Nozzles. As compared to our FullFlow and Standard Air Knives, the Super Air Knives can generate an amplification ratio of 40:1. As an engineered product, we were able to increase efficiency even further.
EXAIR has been manufacturing Intelligent Compressed Air® products since 1983. We can provide solutions that are efficient, effective, and safe for blow-off systems. In comparison, the other blow-off devices are like incandescent light bulbs, while EXAIR products are like LED light bulbs. Entrainment of free ambient air can save you a lot of money when using your compressed air system. If you would like to discuss solutions to use less compressed air and improve your bottom dollar, an Application Engineer at EXAIR is available to help.
If you’re reading the EXAIR Blog, you’re probably well aware that compressed air is the most expensive utility in an industrial environment. The average cost to generate 1000 Standard Cubic Feet of compressed air is $0.25. If you’re familiar with how much air you use on a daily basis, you’ll understand just how quickly that adds up.
To make matters worse, many compressed air systems waste significant amounts of compressed air just through leaks. According to the Compressed Air Challenge, a typical plant that has not been well maintained will likely have a leak rate of approximately 20%!! Good luck explaining to your finance department that you’re carelessly wasting 20% of the most expensive utility.
The six steps to optimizing your compressed air system is something we cover a fair amount on this blog. And there is a real reason for that. Yes, we sell compressed air products. But we are also aware compressed air costs money to generate, so using this source responsibly is very important.
This is where the 6 steps come into play, but today we are just covering Step 3. Which is upgrading your blow off, cooling and drying operations using engineered compressed air products. (If you want to read about the other 5 steps, check them out here, Step #1, Step #2, Step #4, Step #5, Step #6)
I compare step three to replacing your house windows. We recently got some prices to replace our windows, but along with that comes the cost savings we expect to get as they are better designed now than in the 1990ies to retain your temperature inside. Thus reducing the cost to cool and heat your home.
Similar to my “upgrade” to new windows, upgrading blow offs, cooling and drying operations using engineered compressed air products is Step 3 in EXAIR’s Six Steps To Optimizing Your Compressed Air System. We’ve assigned an order to these steps in accordance with basic good engineering practice & protocol, but it’s not necessary to follow them in any particular order. In fact, all six steps really don’t apply to every single compressed air system.
Step 3 does apply to most systems, though. I spent a fair amount of time in all sorts of industrial facilities in my previous roles, and almost all the time, regardless of the industry or the size of the facility, the maintenance and production part of the facility used air guns. However, I don’t recall ever seeing an engineered nozzle on one before I came to EXAIR. Since then, I’ve worked with a bunch of users to dramatically reduce compressed air consumption by replacing their cheap and inefficient air guns with EXAIR Safety Air Guns, or by retrofitting EXAIR Super Air Nozzles onto their existing air guns. We actually carry adapters to fit our Super Air Nozzles to a number of readily commercially available air guns for that very purpose.
In addition to air guns & nozzles, our Air Knives have a long history of replacing drilled pipes & pipe manifolds with inefficient nozzles used to make a curtain of air flow. The following chart details the savings you can get from the use of a 24″ Super Air Knife instead of similar devices for a 24″ wide air curtain:
Even though an electric powered blower will use less electricity than the amount of electricity an air compressor uses to supply an engineered product like the Super Air Knife, the maintenance costs make the total cost of ownership eclipse that of the engineered Air Knife.
Our Case Study Library documents many real-world situations where customers worked with us to gather & publish “before/after” documentation, proving the benefits of Step 3. I encourage you to check those out, and if you think you might have an opportunity to do a Case Study with us, we offer discounts or credit for that…give me a call.
In the pharmaceutical industry, it’s rather critical to ensure products are appropriately marked and labeled. This allows for proper tracing of the product throughout the manufacturing process and ensures the end customer has the necessary information they need on the container the products are packaged in.
For some processes in this industry, labeling applications present a few problems. While in many cases the problems are attributed to static electricity, I recently worked on an application for removing condensation prior to a labeling process. While this is a common application we help serve in the Food & Beverage Industry, this one was a first for me with regards to pharmaceuticals.
The manufacturer of a variety of different pharmaceutical products used for animals was having an issue with a few of their products they produce. They had a line that processes a variety of different styles of products, but with one particular type they were having this issue with the label application.
Some of their products must be held at relatively low temperatures. Throughout the filling process they are held within a refrigerated zone. The area in the facility where the labels are applied is also climate-controlled, but not completely refrigerated. The bottles are only in this location for the brief labeling process before being placed back into coolers, but it was not possible for them to relocate the labeling process elsewhere.
The issue they were having was occurring during the warmer, humid days of summer. As the bottles were placed into the labeling machine, condensation would form that prohibits the label from correctly adhering. This led to a lot of rework and manual label application, while also contributing to some waste as products were held outside of refrigeration for too long.
They began seeking out a solution for blowing off the residual condensation prior to labeling and contacted EXAIR for a solution. To combat this problem, we implemented a two-tiered blowoff solution. There was a rotating table where the product is initially held, (2) Model 110024SS-316 Stainless Steel Super Air Knives were used to provide an initial blowoff inside the contained area. This took care of some of that initial condensation, but left some bottles with still a bit of residual moisture that was still creating issues.
We added a Model 120020 ¾” Super Air Amplifier to blow on each individual bottle immediately prior to labeling to take care of any condensation that formed after the initial blowoff. With both of these solutions in place, the condensation is immediately stripped off the outside of the vials and allows for a clean label application each and every time.
EXAIR offers a wide range of products that can be used for blowoff. Options are available in 316 Stainless Steel from stock for a variety of applications in both the Food and Pharmaceutical Industries.
For help selecting the best products for your process, get in contact with one of EXAIR’s Application Engineers today.
