EXAIR Super Air Knife: Overview

 

Loud and inefficient homemade blowoff

Drilled pipes, like the one shown above, are all too common in industrial settings for processes where a wide surface area needs to be treated. Their popularity can be attributed to how cheap and easy they are to make but in actuality they are very expensive to operate, as they waste large amounts of compressed air, and are very dangerous to operate.

We frequently take calls from customers looking for a more energy efficient, safer solution to replace these types of blowoffs. EXAIR manufactures 3 different styles of Air Knife – the Super, Standard and Full-Flow – that are the ideal solution for wide coverage applications. Today, I would like to provide an overview of our award wining Super Air Knife.

The Super Air Knife

The Super Air Knife is our most efficient air knife in regards to compressed air usage, using only 2.9 SCFM per inch of knife length @ 80 PSIG. It is also the quietest on the market today at only 69 decibels. The Super Air Knife provides the highest air velocity of the 3 styles offered by EXAIR and produces 2.5 ounces of force per inch at 80 PSIG operating pressure. We offer stock lengths from 3” up to 108” in single piece construction with available materials of aluminum, 303ss and 316ss. We also offer PVDF (Polyvinylidene Fluoride) up to 54” for harsh environments.

The Super Air Knife provides a laminar airflow across the entire length with hard-hitting force. They also give a 40:1 amplification rate meaning they entrain 40 parts of the surrounding room air for every 1 part of compressed air used, producing a large volume outlet flow.

Coupling Kit for the Super Air Knives

For applications requiring an air knife length longer than 108″, we offer a coupling bracket kit that allows you to connect two Super Air Knives together for a seamless, uninterrupted flow. Kits are available in aluminum, 303ss or 316ss to match the construction of the knife.

In addition, we also offer plumbing kits as an accessory item. For aluminum Super Air Knives, we offer cut to length nitrile/PVC hose and brass fittings and for stainless steel and PVDF knives we offer 316ss cut-t0-length pipe and fittings.

If you have any questions on how the Super Air Knife might fit into your process, please contact an Application Engineer.

Justin Nicholl
Application Engineer
justinnicholl@exair.com
@EXAIR_JN

Vacuum Generator System Selection – EXAIR E-Vacs

E-Vac Vacuum Generators are a highly efficient, versatile compressed air vacuum pump. Their versatility allows them to be adapted to many applications such as pick and place, clamping or vacuum forming. They’ve also been used in more unique applications like wood veneer pressing and basketball deflation.

EXAIR manufactures (3) types of E-Vacs – Low vacuum generators for porous materials, like cardboard, generating up to 21″ Hg with vacuum flows as high as 18.5 SCFM. Our high vacuum generators, designed for use with non-porous materials like glass or steel sheets, produce vacuum levels up to 27″ Hg and up to 15.8 SCFM of vacuum flow. The adjustable generators provide flexible vacuum performance, up to 25″ Hg and 81 SCFM,  which can be easily adapted to meet the application.

EXAIR E-Vacs provide instantaneous vacuum response, and are engineered for high efficiency to minimize air consumption.

 

When making a selection, there are a few key areas you want to consider:

Is the material porous or non-porous?

  • This will allow you to select the proper type of vacuum generator to fit the application and the type of vacuum cup best suited for the process.

 

What is the weight of the part and how will it be lifted?

  • If the part is being lifted where the vacuum cups will be positioned horizontally, like on top of a sheet of glass, you want to use a safety factor of 2 times the actual weight of the part. In processes requiring the cups be positioned vertically on the part, such as picking up a sheet of plywood and hanging it on an overhead conveyor, a safety factor of 4 would be used.

 

How many Vacuum Cups do I need?

  • Consider the quantity and placement to evenly distribute the weight for safely moving the material.
  • Depending on the maximum vacuum the generator produce, how much weight can each cup lift?
  • Make the cup selection per the following chart

 

Once you have selected the type and number of cups needed, you can then begin to look at which additional accessories items you might need.

  • Filters – supplying clean, dry air is key for maintaining optimal performance. An automatic drain filter  can be used to remove any water or contaminants in the supply line. If there is oil present, consider using an Oil Removal Filter.
  • Mufflers – help to reduce the noise level without restricting the airflow. We offer 2 different styles – Standard and Straight Through. Standards mufflers are a good choice where the supply air is clean and dry. These mufflers can only be used with the porous and non-porous generators. The Straight Through mufflers reduces sound levels by up to 26 dBA and are the better choice in processes where dirt or particulate may be present.
  • Tubing and Fittings – polyurethane tubing is available in 10′ sections up to 50′ for processes requiring the vacuum cups be placed in a location that wouldn’t allow for direct mounting to the NPT vacuum port on the generator or where multiple cups are needed. You want to keep the length of tubing as short as possible though for effective pickup and release time.
  • Check Valve – will maintain vacuum on the load if the supply pressure were to drop or be lost during operation.

For additional assistance selecting the proper E-Vac and accessories for your process, please contact an application engineer at 800-903-9247.

Justin Nicholl
Application Engineer
justinnicholl@exair.com
@EXAIR_JN

 

Machining Plastics? Consider The Cold Gun For A Clean Operation

Machining plastics can be a difficult task as the contact between the part and the tool generates heat, which can result in the plastics beginning to melt and stick to the tooling, causing deformities or even broken tool heads. Often times, companies will introduce a liquid based method of cooling to quench the parts during machining, while this does work, with plastics they tend to absorb some of the liquid, resulting in the finished part being outside the allowable tolerance range. Another area of concern is the mess that liquid cooling creates as now the parts need to be dried and cleaned before they can continue to the next process.

Coolant based systems can be messy and costly to operate

Such was the case last week when I worked with an OEM who was looking for a way to cool the tooling in the machines they build for the plastics industry. The company they were selling the machines to, specifically asked for an alternative method of cooling without using any type of coolant due to the conditions mentioned above. Once again, EXAIR has the perfect solution – the Cold Gun. Incorporating a Vortex Tube, the Cold Gun produces a cold air stream at 50°F below compressed air supply temperature and provides 1,000 Btu/hr. of cooling capacity. Fitted with a magnetic base and flexible hose the unit can be mounted virtually anywhere on the machine and the cold airflow can be easily directed to provide cooling to the critical area. The system also includes a filter separator for the supply line to remove any water or contaminants, ensuring that the exiting airflow is clean and free of debris.

No moving parts = maintenance free

 

When looking for a reliable method of cooling, whether machining plastics or other material, the cold, clean air from the Cold Gun is the ideal solution in place of messy misting systems. For help with your spot cooling needs or to discuss how using Vortex Tube technology could help in your process, give me a call, I’d be happy to help.

Justin Nicholl
Application Engineer
justinnicholl@exair.com
@EXAIR_JN

 

Coolant Spraying in the Mini Mill image courtesy of Andy Malmin via Creative Commons license

Proper Supply Lines are Key to Air Knife Performance

A few weeks back I chatted with a customer on an Air Knife application where they were using our 48″ aluminum Super Air Knife to remove leftover dough from a baking pan. The knife was working somewhat, but they were seeing some residual dough being left in certain areas on the pans due to what they perceived as “weak” airflow. After reading through our catalog and installation guide, they noticed that there were available shim sets that would allow them to increase the gap setting to get more force and flow out of the knife.

Available in lengths from 3″ to 108″ in aluminum, 303ss or 316ss construction

Our aluminum Super Air Knives are shipped from stock with a .002″ shim installed. The optional shim set includes a .001″, .003″ and .004″ shim that would allow you to decrease or increase the performance. By operating the Super Air Knife with the .003″ shim installed, this would increase the force and flow by 1.5 times and using the .004″ shim would double the performance. Sometimes achieving greater force and flow may be required but with the customer saying they were seeing weak airflow, it seemed there may be a restriction on the supply side.

Super Air Knife with Shim Set

I asked the customer how the knife was plumbed and what size supply lines he was using. He advised that they were plumbing air to all 3 inlets on the bottom of the knife but they were using 3/4″ hose with a run of about 30′. I advised the customer that plumbing air to all 3 inlets is required for a 48″ Super Air Knife but we actually recommend 3/4″ Schedule 40 Pipe up to 10′ or 1″ pipe up to 50′. If using hose, he would need to go up a size to maintain a large enough ID to carry the volume required for the unit. In his case, since the length of the supply is close to 30′, he would need to use 1-1/4″ ID hose.

Improper plumbing line size is a common issue we deal with here at EXAIR. Using undersized supply lines can cause excessive pressure drops because they aren’t able to carry the volume of air necessary to properly supply the compressed air device. In this particular application, if the customer were to install either the .003″ or .004″ shim, while keeping his current plumbing size, the performance would actually be worse as now the lines are even more undersized due to the increased air volume requirement from the larger Super Air Knife gap.

If you are looking to change the performance with one of our Air Knives or if you would like to discuss a particular application or product, please contact one of our application engineers for assistance at 800-903-9247.

Justin Nicholl
Application Engineer
justinnicholl@exair.com
@EXAIR_JN

Custom Solutions For Conveying Dry Material

The ideal solution for conveying large volumes of material over long distances.

EXAIR’s Line Vac compressed air operated conveyors have no moving parts or motors to wear out, providing a maintenance free way to move dry material from one location to another. We offer several different types and sizes of Line Vacs like our Standard Line Vacs, available from 3/8″ up to 5″  or our Threaded Line Vacs, with NPT threaded connections up to 3″. The Heavy Duty Line Vac are constructed of Hardened Alloy for superior abrasion resistance, available in sizes from 3/4” to 3”, smooth and threaded connections or the Light Duty Line Vac commonly used for smaller volume, shorter distance processes, with sizes from 3/4″ to 6”. We even offer Sanitary Flange Line Vacs from 1-1/2″ up to 3″ for processes requiring frequent cleaning. All of these products are in stock, ready to ship from our factory here in Cincinnati, Ohio.

For over 34 years, EXAIR has been manufacturing Intelligent Compressed Air Products and we understand that there may be “special” cases where a stock product isn’t going to fit a specific need or requirement. What sets us apart from our competition is that we are able, with a little help from the customer, to engineer and manufacture custom made products, like the Line Vac Conveyors, to fit the specific demand of a unique application.

A few examples are shown below:

Flanged design, easy to install


This special 3/4″ Stainless Steel flanged Line Vac is being used to remove acidic vapors after a silicon wafer etching process. The flanged design allowed the user to direct mount to the machine, eliminating the need for other expensive modifications.

 

 

 

Chemical resistant construction for washdown areas

 

 

A customer was needing a special Line Vac for a chloride wash area due to the aggressive chemicals. We were able to make a custom 1-1/2″ Line Vac in PVDF construction for corrosion resistance and QF flanges for easy maintenance and cleaning.

 

 

 

Custom funnel design for small, granulated material like sugar or salt

 

This special funnel shaped Line Vac is being used in a a small packet filling operation. The unique design assured for a clog free process by keeping the granulated material moving through the tube.

 

 

 

 

 

Miniature size for confined workspaces

 

A company was needing a miniature version of a Line Vac to remove microscopic debris in an integrated circuit chip making process. The barb fittings allowed for easy installation into the small work place.

 

 

 

 

 

These are just a few examples of how we are able to meet the demands of a wide variety of extraordinary processes. Whether you are looking to move “common” materials like plastic pellets or maybe something “off the wall”, chances are we have the resources to provide an engineered solution to fit your need. Our application engineers are standing by, so give us a call and let us put our expertise to work for you!

Justin Nicholl
Application Engineer
justinnicholl@exair.com
@EXAIR_JN

 

 

Estimating the Cost of Compressed Air Systems Leaks

Leaks in a compressed air system can waste thousands of dollars of electricity per year. In fact, in many plants, the leakage can account for up to 30% of the total operational cost of the compressor. Some of the most common areas where you might find a leak would be at connection joints like valves, unions, couplings, fittings, etc. This not only wastes energy but it can also cause the compressed air system to lose pressure which reduces the end use product’s performance, like an air operated actuator being unable to close a valve, for instance.

One way to estimate how much leakage a system has is to turn off all of the point-of-use devices / pneumatic tools, then start the compressor and record the average time it takes for the compressor to cycle on and off. The total percentage of leakage can be calculated as follows:

Percentage = [(T x 100) / (T + t)]

T = on time in minutes
t = off time in minutes

The percentage of compressor capacity that is lost should be under 10% for a system that is properly maintained.

Another method to calculate the amount of leakage in a system is by using a downstream pressure gauge from a receiver tank. You would need to know the total volume in the system at this point though to accurately estimate the leakage. As the compressor starts to cycle on,  you want to allow the system to reach the nominal operating pressure for the process and record the length of time it takes for the pressure to drop to a lower level. As stated above, any leakage more than 10% shows that improvements could be made in the system.

Formula:

(V x (P1 – P2) / T x 14.7) x 1.25

V= Volumetric Flow (CFM)
P1 = Operating Pressure (PSIG)
P2 =  Lower Pressure (PSIG)
T = Time (minutes)
14.7 = Atmospheric Pressure
1.25 = correction factor to figure the amount of leakage as the pressure drops in the system

Now that we’ve covered how to estimate the amount of leakage there might be in a system, we can now look at the cost of a leak. For this example, we will consider a leak point to be the equivalent to a 1/16″ diameter hole.

A 1/16″ diameter hole is going to flow close to 3.8 SCFM @ 80 PSIG supply pressure. An industrial sized air compressor uses about 1 horsepower of energy to make roughly 4 SCFM of compressed air. Many plants know their actual energy costs but if not, a reasonable average to use is $0.25/1,000 SCF generated.

Calculation :

3.8 SCFM (consumed) x 60 minutes x $ 0.25 divided by 1,000 SCF

= $ 0.06 per hour
= $ 0.48 per 8 hour work shift
= $ 2.40 per 5-day work week
= $ 124.80 per year (based on 52 weeks)

As you can see, that’s a lot of money and energy being lost to just one small leak. More than likely, this wouldn’t be the only leak in the system so it wouldn’t take long for the cost to quickly add up for several leaks of this size.

If you’d like to discuss how EXAIR products can help identify and locate costly leaks in your compressed air system, please contact one of our application engineers at 800-903-9247.

Justin Nicholl
Application Engineer
justinnicholl@exair.com
@EXAIR_JN

 

 

 

 

 

Proper Supply Line Size And Fittings Provide Peak Performance

Many times when we provide the air consumption of an EXAIR product, we get a response like…. “I’ve got plenty of pressure, we run at around 100 PSIG”. While having the correct pressure available is important, it doesn’t make up for the volume requirement or SCFM (Standard Cubic Feet per Minute) needed to maintain that pressure. We commonly reference trying to supply water to a fire hose with a garden hose, it is the same principle, in regards to compressed air.

When looking to maintain an efficient compressed air system, it’s important that you use properly sized supply lines and fittings to  support the air demand (SCFM) of the point-of-use device. The smaller the ID and the longer the length of run, it becomes more difficult for the air to travel through the system. Undersized supply lines or piping can sometimes be the biggest culprit in a compressed air system as they can lead to severe pressure drops or the loss of pressure from the compressor to the end use product.

Take for example our 18″ Super Air Knife. A 18″ Super Air Knife will consume 52.2 SCFM at 80 PSIG. We recommend using 1/2″ Schedule 40 pipe up to 10′ or 3/4″ pipe up to 50′. The reason you need to increase the pipe size after 10′ of run is that 1/2″ pipe can flow close to 100 SCFM up to 10′ but for a 50′ length it can only flow 42 SCFM. On the other hand, 3/4″ pipe is able to flow 100 SCFM up to 50′ so this will allow you to carry the volume needed to the inlet of the knife, without losing pressure through the line.

Pipe size chart for the Super Air Knife

We also explain how performance can be negatively affected by improper plumbing in the following short video:

 

Another problem area is using restrictive fittings, like quick disconnects. While this may be useful with common everyday pneumatic tools, like an impact wrench or nail gun, they can severely limit the volumetric flow to a device requiring more air , like a longer length air knife.

1/4″ Quick Connect

For example, looking at the above 1/4″ quick disconnect, the ID of the fitting is much smaller than the NPT connection size. In this case, it is measuring close to .192″. If you were using a device like our Super Air Knife that features 1/4″ FNPT inlets, even though you are providing the correct thread size, the small inside diameter of the quick disconnect causes too much of a restriction for the volume (SCFM) required to properly support the knife, resulting in a pressure drop through the line, reducing the overall performance.

If you have any questions about compressed air applications or supply lines, please contact one of our application engineers for assistance.

Justin Nicholl
Application Engineer
justinnicholl@exair.com
@EXAIR_JN