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

Not All Compressed Air Guns Are The Same

If you work in an industrial plant or manufacturing environment, chances are you use some type of compressed air gun for cleaning parts, work areas, etc. Many air guns purchased through large industrial suppliers are a common choice due to the cost of the gun but as the saying goes – “you get what you pay for”. These types of guns may be cheap to purchase but they are also made cheap and have parts that can break easily, like the trigger or nozzle. In many cases, the nozzles on these guns are also in violation of OSHA requirements, producing dangerous discharge pressures and loud noise levels, which can lead to costly fines or potentially deadly injuries.

EXAIR offers 5 different styles of Safety Air Guns that not only eliminate these concerns, but also provide a more efficient operation, which can reduce energy costs. All of our Safety Air Guns are fitted with our engineered Air Nozzles  which meet OSHA Standard 1910.242(b) for 30 PSI dead end pressure, as they provide a relief or safe path for the air to exit if the nozzle were to be blocked or pressed against an operator’s body so the exiting air pressure will never reach 30 PSIG. They are also engineered to entrain surrounding air across the profile of the nozzle, which produces a smoother airflow, ultimately reducing wind shear, resulting in much lower sound levels, meeting OSHA Standard 29 CFR 1910.95(a).

 

 

The Precision Safety Air Gun body is made of a durable high impact, glass reinforced nylon, providing for a lightweight, ergonomic operation. These guns feature a curved extension, ideal for delivering a powerful stream of air in hard to reach areas, like clearing debris from drilled holes. All of the nozzles used with these units are either 316ss construction for durable, corrosion resistance or PEEK plastic for non-marring applications. The air inlet is 1/4 FNPT and there is a convenient hanger available for safe storage.

 

 

 

Our NEW VariBlast Compact Safety Air Guns are ideal for light to medium duty processes, featuring a variable flow trigger to achieve different force levels ranging from 2.0 ounces up to 1 pound, depending on the nozzle. The body is cast aluminum and there are (2) 1/4 FNPT air inlets available, 1 on the bottom and 1 on the back of the gun, as well as a storage hanger, for easy installation. Nozzles are available in zinc aluminum alloy, 303ss, 316ss and PEEK plastic. These guns are available with aluminum extensions from 6″ up to 72″.

 

 

The Soft Grip Safety Air Guns are commonly used in long-term use applications as they feature a comfortable grip and long trigger which helps to reduce hand and finger fatigue. The cast aluminum construction is well suited for more rugged environments and again, features a hanger hook. These guns can be fitted with aluminum, stainless steel or PEEK plastic to meet the demands of a variety of applications and are available with 6″ – 72″ aluminum extensions for extra reach or Flexible Stay Set Hoses , allowing the user to aim the airflow to a specific target area. The air inlets for these guns are going to be 1/4 FNPT.

 

 

 

EXAIR’s Heavy Duty Safety Air Guns deliver higher force and flows than other air guns, as these units feature a 3/8 FNPT air inlet, which maximizes the compressed air flow to the engineered Super Air Nozzle. Like the Soft Grip, the durable cast aluminum body is designed for use in tough industrial processes, and the ergonomic and comfortable trigger are ideal for hours of use. Aluminum extension are available, again in lengths from 6″ up to 72″, but feature a larger diameter for optimal flow and superior durability.

 

The Precision, VariBlast, Soft Grip and Heavy Duty Safety Air Guns are ALL available with an optional, polycarbonate Chip Shield to protect personnel from flying chips and debris, further meeting OSHA Standard 1910.242(b) for the safe use of compressed air.

 

Lastly we offer our Super Blast Safety Air Guns. The Super Blast Safety Air Guns are ideal for wide area blowoff, cooling or drying a part, as well as long distances. They feature a comfortable foam grip and spring loaded valve that will shut off the airflow if the gun is dropped. These units use our larger Super Air Nozzles and Super Air Nozzle Clusters, providing forces levels from 3.2 lbs. up to 23 lbs. Depending on which nozzle is fitted on the assembly, air inlets will range from 3/8 FNPT up to 1-1/4 FNPT. Aluminum extensions are available in 36″ or 72″ lengths.

 

 

For help selecting the best product to fit your particular application, please contact one of our application engineers for assistance.

Justin Nicholl
Application Engineer
justinnicholl@exair.com
@EXAIR_JN

 

Vortex Tube Cools Glue On A Paper Folding Machine

I recently worked on a cooling application with an engineering company who designed a paper folding machine for their customer. As the paper enters the machine, it travels over a series of rollers or “plows” that folds the paper into the desired design. At the last step a heated glue is applied to the edge so the paper stays folded. After the paper leaves the folder it is sent to a stack machine to be processed and packaged for shipment. It was at this area they were starting to see some issues arise as the glue was retaining heat, causing it to leak onto the dividers of the stacker or other finished papers.

Example of a paper folding machine

To try and remedy the situation, the customer had installed an air nozzle to blow compressed air across the last fold and while this did work somewhat, they had to operate at really low pressure so they didn’t cause the paper to move while trying to cool the glue. This slowed the process down, which was negatively affecting their production output, so they reached out for assistance on a more reliable solution.

After further discussing the process with the design company, I recommended they use our Model # 3908 Small Vortex Tube Cooling Kit. The Vortex Tube Cooling Kits include the Vortex Tube, cold muffler, tubing, filter separator and all of the generators to change the flow rate and cooling capacity of the Vortex Tube during operation. The temperature drop from the supply air temperature and the volume of air being exhausted can be controlled by adjusting the valve in the hot end to change the cold fraction (the percentage of air being exhausted out of the cold end versus the amount of air being exhausted out of the hot end).

Items included in a Vortex Tube Cooling Kit

By incorporating the Cooling Kit into the process, the customer would be able to experiment with the airflow and temperature to achieve an acceptable balance, providing enough cold air to cure the glue, while not disrupting the process. If you have a similar process you would like to discuss, please contact an application engineer at 800-903-9247 for assistance.

Justin Nicholl
Application Engineer
justinnicholl@exair.com
@EXAIR_JN

The Folding Machine 4 image courtesy of Ms. Tharpe via creative commons license

EXAIR Leads the Way with Standards and Certifications

For over 34 years, EXAIR has been the industry leader in providing Intelligent Compressed Air Products to the industrial marketplace. While much of our focus is to ensure our products are engineered to provide optimal performance, we are also dedicated to manufacturing products that meet a wide range of standards and directives to promote safety in relation to plant personnel.

 

For instance, all of our compressed air operated products meet or exceed OSHA Standards 29 CFR 1910.242(b), requiring that the outlet pressure of an open pipe, nozzle, air gun, etc., when used for cleaning purposes, must remain below 30 PSI when dead-ended against the skin, as well as Standard 29 CFR 1910.95(a) as a way to protect workers from job related injuries related to dangerous sound levels of 90 dBA and higher.

 

 


Many of our products are also CE Compliant, meeting the mandatory requirements for products intended to be sold in the European Economic Area or “EEA”. For example our Electronic Flow Control and Electronic Temperature Control (ETC) meet the EU (European Union) Low Voltage Directive 2006/95/EC.

 

 

EXAIR electrically powered devices, like our Static Eliminators and Digital Flowmeters for example, comply with the “Restriction of Hazardous Substances” or RoHS Directive 2011/65/EU, including the amendment outlined in the European Commission decision L 214/65.

 

 

We are also committed to providing material that supports the conflict mineral free rule to help aid in the relief of illegal trade of exotic materials, like tungsten, gold, tin and tantalum in the DRC region. Using the CMRT 4.20 template, we document our supply resources to ensure we provide conflict free products, as outlined in Section 1502 of the Dodd-Frank Wall Street Reform and Consumer Protection Act.

 

Lastly, the European Union introduced the REACH program – Registration, Evaluation, Authorization and Restriction of Chemicals, as a method to register chemical substances being imported into the EU to protect people and the environment, per Regulation (EC) No 1907/2006 Title I, Article 3.  Also noted in the program, Title II, Article 7, they state that any product with a substance intended to be released under normal operating conditions, must be registered for quantities totaling more than 1 metric ton per year. Since EXAIR products do not intentionally release or contain any such substances, registration to meet the program is not required.

 

If you have any questions about any of these Standards or Directives or about which EXAIR products comply, please feel free to contact an application engineer for assistance. We’d be happy to help!

Justin Nicholl
Application Engineer
justinnicholl@exair.com
@EXAIR_JN

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