Tag: compressed air plumbing

Super Air Knife Plumbing Kits Ensure Proper and Optimum Operation

Published on by Leave a comment

The EXAIR Super Air Knife is a Highly Engineered and intelligently designed point of use compressed air powered device that delivers a 40:1 air amplification ratio!  This simply means that for every one part compressed air supplied to an EXAIR Super Air Knife it will entrain 40 parts ambient air into the exiting compressed air stream.  Almost as good as “money for nothing”!  Also the EXAIR Super Air Knife is designed to provide an even or “laminar” flow of air.  This is due to it being an intelligent, highly engineered compressed air product.

However if an EXAIR Super Air Knife is not connected to the compressed air supply with the appropriate number of inlet ports being fed, poor and/or erratic performance is likely.  This would manifest itself as uneven air flow and lower performance from the air knife.  In order to make this plumbing easier we offer optional plumbing kits for all Super Air Knives starting with the 24″ length all the way up to the 108″!  The 24″ and longer Super Air Knive’s require that compressed air must be supplied to multiple air inlets along its length for optimal performance.  This will ensure that the air flow is laminar and the force is even across the entire length of the Super Air Knife.  All our products are shipped with an installation guide referencing the proper recommended pipe sizes for various lengths of supply pipe.

The Plumbing Kits for Aluminum Super Air Knives provide properly sized Nitrile/PVC Hoses, Brass Fittings and a Pressure Gauge which monitors the inlet pressure to the air knife.  If the gauge shows a pressure drop when the Super Air Knife is turned on this indicates that there is an air starvation issue.  For the 303SS, 316SS and PVDF Air Knives the Plumbing Kits contain 5/8 OD SS tubing X .034 wall thickness tubing and SS fittings.

AirKnifePlumbing

So when ordering your next Super Air Knife be sure to designate the Plumbing Kit to ease your installation and to ensure top performance.

When you are looking for expert advice on safe, quiet and efficient point of use compressed air products give us a call.   We would enjoy hearing from you!

Steve Harrison
Application Engineer
Send me an email
Find us on the Web 
Follow me on Twitter
Like us on Facebook

Intelligent Compressed Air: Refrigerant Dryers and How They Work

Published on by Leave a comment

We’ve seen in recent blogs that Compressed Air Dryers are an important part of a compressed air system, to remove water and moisture to prevent condensation further downstream in the system.  Moisture laden compressed air can cause issues such as increased wear of moving parts due to lubrication removal, formation of rust in piping and equipment, quality defects in painting processes, and frozen pipes in colder climates.  The three main types of dryers are – Refrigerant, Desiccant, and Membrane. For this blog, we will review the basics of the Refrigerant type of dryer.

All atmospheric air that a compressed air system takes in contains water vapor, which is naturally present in the air.  At 75°F and 75% relative humidity, 20 gallons of water will enter a typical 25 hp compressor in a 24 hour period of operation.  When the the air is compressed, the water becomes concentrated and because the air is heated due to the compression, the water remains in vapor form.  Warmer air is able to hold more water vapor, and generally an increase in temperature of 20°F results in a doubling of amount of moisture the air can hold. The problem is that further downstream in the system, the air cools, and the vapor begins to condense into water droplets. To avoid this issue, a dryer is used.

Refrigerated Dryer
Fundamental Schematic of Refrigerant-Type Dryer

Refrigerant Type dryers cool the air to remove the condensed moisture and then the air is reheated and discharged.  When the air leaves the compressor aftercooler and moisture separator (which removes the initial condensed moisture) the air is typically saturated, meaning it cannot hold anymore water vapor.  Any further cooling of the air will cause the moisture to condense and drop out.  The Refrigerant drying process is to cool the air to 35-40°F and then remove the condensed moisture.  The air is then reheated via an air to air heat exchanger (which utilizes the heat of the incoming compressed air) and then discharged.  The dewpoint of the air is 35-40°F which is sufficient for most general industrial plant air applications.  As long as the compressed air stays above the 35-40°F temperature, no further condensation will occur.

The typical advantages of Refrigerated Dryers are-

  1.  – Low initial capital cost
  2.  – Relatively low operating cost
  3.  – Low maintenance costs

If you have questions about getting the most from your compressed air system, or would like to talk about any EXAIR Intelligent Compressed Air® Product, feel free to contact EXAIR and myself or one of our Application Engineers can help you determine the best solution.

Brian Bergmann
Application Engineer

Send me an email
Find us on the Web 
Like us on Facebook
Twitter: @EXAIR_BB

 

Proper Supply Lines are Key to Air Knife Performance

Published on by exaircorpLeave a comment

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

Proper Supply Line Size And Fittings Provide Peak Performance

Published on by exaircorpLeave a comment

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