What’s So Great About Threaded Line Vac Pneumatic Conveyors?

Conveyor systems come in many shapes, sizes, and configurations. They can be run at different speeds, and are made of various materials, depending what they’re carrying, and why they’re carrying it. And sometimes, they’re hilarious:

If you’re looking to move solids, in bulk, through pipe, there’s not a simpler way to do it than with an EXAIR Threaded Line Vac.  Like our ‘standard’ Line Vacs, they use compressed air to generate a powerful vacuum flow to get air behind the pieces and carry them along:

Instant conveyor – just add compressed air.

But, while the ‘standard’ Line Vacs are made for use with Conveyance Hose, the Threaded Line Vacs have male NPT threads so you can pipe them in line.  We have a range of options, depending on the nature of your applications:

  • Sizes: 3/8 NPT to 3 NPT.
  • Materials: aluminum, 303SS, 316SS, and hardened alloy.
  • Performance: aluminum, 303SS and 316SS Threaded Line Vacs are made for standard duty; the hardened alloy Heavy Duty Threaded Line Vacs offer higher vacuum performance as well as superior abrasion resistance.
  • Environment: the materials of construction listed above may be important because of the nature of the product being conveyed, but they also have different temperature ratings.  Our Stainless Steel Line Vacs also come in a High Temperature design, in case the material – or the environment – is particularly hot:
    • Aluminum: 275°F (135°C)
    • Heavy Duty Hardened Alloy: 400°F (204°C)
    • 303 or 316SS: 400°F (204°C)
    • High Temp 303 or 316SS: 900°F (482°C)

If you’ve got a conveyor application you’d like to discuss, give me a call.

Russ Bowman
Application Engineer
EXAIR Corporation
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Torque Values and Tapered Threads – Do They Go Together?

IMG_20200202_155004_377.jpg

Over the past few weeks, I have been working on various cars in the garage with some good friends. We generally get together and help each other out to make the jobs go easier as well as help each other learn more about keeping our family’s vehicles safe and even helping out some others that don’t have the means to work on their own vehicles. Throughout these repairs, we always end up in some type of discussion over something fairly technical. Sometimes it is the proper installation of a part such as take the bolts to snug, back them out, then torque to half the total torque value, back off again, then finally tighten to the complete torque.

We also share different ways of doing the jobs, such as how to lessen the amount of hot oil you are about to pour all over your hand, or how to get that rusted bolt out without a torch and without breaking it. One discussion that comes up quite frequently is torque specs and then the torque spec for a tapered thread.

In case you were not aware, the NPT or BSPT (male) inlets on EXAIR products are both a tapered thread. Tapered threads are generally used on pipe fittings under pressure to seal better and provide a secure engagement. When comparing this to a standard bolt, or straight thread, one is generally accustomed to receiving a torque spec on just how tight to get the fitting or threaded product. For example, the 1/4-20 bolts used in our Super Air Knives are torqued to 7.5 ft-lbs. in order to properly seal the cap, shim, and body together. These are straight threads and thus a torque spec is often driven by the material, size, and thread of the bolt. Torque on tapered threads such as NPT or BSPT fittings is not as easy to find, and not really reliable.

For tapered threads, the engagement of the thread is not always at the same point due to differing tolerances on thread dimensions. These differences create different points of thread engagement with the corresponding thread it is tightening into. For these scenarios, the torque specification is not always best suited as a numeric value. If you search hard enough you can find a table like the one shown below, but again, not the best value to use when installing a tapered thread.

Size in-lbs N-m
1/16″ 5 0.57
1/8″ 7 0.79
1/4″ 16 1.81
3/8″ 23 2.6
1/2″ 30 3.39
3/4″ 54 6.1
1″ 78 8.81

I personally would not use a straight numeric torque when tightening something with stainless steel thread into a brass fitting, or other dissimilar materials together. For this scenario, I would recommend using something like the table below. The TPFT value is, turns past finger tight. This means you would snug the super air nozzle, vortex tube, or other fittings by hand to finger tight. Then using a wrench or two if needed, turn the fitting to the correct number of revolutions for the given thread size. By utilizing this method and the correct amount of thread sealant, see John Ball’s video blog below, you can ensure there will not be a concern on whether or not the joint will leak and also if the fitting is tight enough.

NPT Size TPFT
1/8″ 2-3
1/4″ 2-3
3/8″ 2-3
1/2″ 2-3
3/4″ 2-3
1″ 1.5-2.5

If you would like to discuss torque settings, installation of your engineered compressed air solution, or even what might be wrong with your minivan, contact us.

Brian Farno
Application Engineer/Garage Mechanic Extraordinaire
BrianFarno@EXAIR.com
@EXAIR_BF

Keeping the Confusion Out of NPT Pipe Thread Dimensions

I recently had the pleasure of helping a caller solve a problem with a Super Air Nozzle.  He had measured the opening on the outlet of his air gun, and ordered accordingly…unfortunately, he didn’t know that 3/8 NPT did NOT correspond to a 3/8″ diameter of a threaded fitting.  I explained the reason for this, a while back, in a blog entitled “When Is A Half Inch Not A Half Inch? When It’s Half Inch Pipe, Of Course!

The ID of a 1/8 NPT threaded fitting is actually pretty close to 3/8". Here's a dimensions table that I reference often.
The ID of a 1/8 NPT threaded fitting is actually pretty close to 3/8″ (left.) Here’s a link to a dimensions table that I reference often to keep this (on right, a 3/8 NPT nozzle with an 1/8 NPT air gun) from happening.

 

As you can see, the Model 1105 3/8 NPT Super Air Nozzle will not fit the 0.405″ (not far at all from 3/8″ if measured with a ruler) ID of a 1/8 NPT threaded connection.  No matter; these are all catalog parts that we have plenty of stock on, so, after a brief discussion of pipe thread sizes, he got a Model 1103 1/8 NPT Super Air Nozzle, and it fits just fine:

IMG_5789
Model 1103 1/8 NPT (male) Super Air Nozzle installed in a 1/8″ NPT air gun.

Sometimes, an adapter is required for air guns that have straight threads.  Two common sizes for these are 5/8″-28 and 3/4″-32 – and we have adapters for both of these (call for details.) Other adapters are readily commercially available…you may find them in the plumbing aisle of your hardware store, or from a local pipe & pipe fitting supplier.  We’ve seen some air guns, though, that have a proprietary thread that doesn’t match up to anything else…in these cases, we have four types of Safety Air Guns on the shelf, ready to ship.

If you’d like to find out more about using quiet and efficient engineered Super Air Nozzles for your air gun applications, give me a call.

Russ Bowman
Application Engineer
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Not All Quick Disconnects Are Equal

Quick disconnect pneumatic fittings have been a staple in any manufacturing facility I have ever visited in my 10+ years as part of the manufacturing world.   The fact is, they have been around for a lot longer than 10 years.   The style we see most often is the 1/4″ Quick Disconnect Fitting, and we are typically troubleshooting a lack of air volume problem because they are not sized properly for the application.  These can be found in any industrial supply companies catalog, your local hardware stores, and even auto parts stores.   Quick Disconnects are even sold with certain EXAIR Industrial Housekeeping products, the key being they are properly sized.

Properly sizing the quick disconnect is a critical step in the process of deciding how to lay out your piping system as well as how to ensure products operate at optimal performance.  As you can see in the picture above, the two quick disconnects on the left are both larger quick disconnects as well as larger NPT thread sizes.   The two on the right are smaller and probably a bit more common to see.  Also notice the thread sizes on each, these are also manufactured in many other NPT thread options.   The through hole on the quick disconnects is decided by the size of the QD, not the thread size on the other end.   The example I am illustrating is comparing the 3/8 NPT and 1/4 NPT quick disconnects: Even though you can have 3/8 NPT threads, your throat diameter of the QD is still restricted to .195″ I.D., the same as the 1/4 NPT.  This can be a large restriction on a product with a 3/8 NPT thread size.

The Inner Diameters of the Quick Disconnects

Also to be noted is that all QD’s of the same size are not made equally, tests have shown that you can lose as much as 20 psi through a quick disconnect and up to 40 psi when not properly matched with the female QD.   This leads to the next step which is to ensure that you are not purchasing a QD on appearance.  MAke sure to choose the QD designed to permit the amount of air you need to operate your point of use product without a volume or pressure loss.

These two points are reasons why quick disconnects can diminish your point of use compressed air product performance.  If you have questions on which size to use with your EXAIR product or need help determining why your point of use product is not performing how you would like, contact us.

Brian Farno
Application Engineer Manager
BrianFarno@EXAIR.com
@EXAIR_BF