Torque Values and Tapered Threads – Do They Go Together?

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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

Video Blog: How-To Replace The Super Air Scraper Blade

The EXAIR Soft Grip Super Air Scraper is a great tool for any industrial environment that requires some cleanup. Some examples include removing tapes or sticky metal chips from the floor, scraping material from screening towers or removing stubborn adhesives and labels from workstation tabletops. They are available with extensions up to 72″ so reaching remote areas is also easier.

Today’s video is going to showcase how easy it is to replace the scraper blade within the nozzle and get back to work quickly.

If you would like to discuss how the Super Air Scraper could benefit your facility, contact us.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

Product Discovery: Super Air Wipes

Airflow through the Super Air Wipe

The Super Air Wipes provide a full 360° conical airflow that is used to blow-off, cool, clean and dry products. A Coanda profile is designed into the body of the unit to maximize entrainment of ambient air as well as give the precision angle for the air to exit from. This gives the air stream impacting the target zone a 30° angle to the surface in order to provide a substantial shear force for debris removal. This also ensures the large volume of ambient air entrained will all travel the correct direction and not become turbulent before impinging on the surface.

Easy clam-shell installation

To provide ease of installation, a unique clam-shell design was engineered to provide clamp over installation rather than traditional threading methods. This also permits quick changes in size when needed in the rapid product change environments.

Super Air Wipe Family Photo

To meet all the tasks at hand, the Super Air Wipes are offered in two main materials of construction. Aluminum body with brass air fittings, connected with stainless steel hardware, shim and connecting hose for up to 4” (102mm). As well as 303 stainless steel body with stainless steel bolts, shim, the connecting hose for up to 4” (102mm) and fittings. The stainless-steel components give the units better corrosion resistance, higher temperature ratings, and more durability in harsh industrial environments.

EXAIR stocks the aluminum Super Air Wipes with inner diameters from 3/8” (10 mm) for wire and cables up to 11” (279mm) for large pipes and hoses. The aluminum models have a temperature rating up to 400oF (204oC). We also stock the stainless-steel models from ½” (13mm) to 4” (102mm) inner diameters, and they have a temperature range up to 800oF (427oC). If you require different diameters or materials, we can do that as well easily.

Super Air Wipe Kit

The Super Air Wipe kits to help get the most out of the air wipes. A kit will include the Super Air Wipe, a filter, regulator and shim set. The filter will remove bulk liquids and debris from the compressed air to keep the performance optimal. The regulator is used to fine-tune the force provided by the Super Air Wipe. This helps to not over-use the amount of compressed air required for the job.

With a regulator, you can make fine adjustments to get the proper amount of air. For coarse adjustments, you can add shims to increase the airflow and force. They are easy to install on the Super Air Wipes to allow for applications to have more cooling, faster drying, and better removal for tough debris. For cleanliness and control, the Super Air Wipe Kits would be recommended for your application.

Robotic Welder fitted with EXAIR Super Air Wipe

With the creation of the Super Air Wipe, uniform cleaning, cooling, and blowing around the outside of parts is a simple task. You don’t have to worry about a variety of nozzles to target the circumference or a fabricated blow-off device that will waste air and take much time out of your day. A simple purchase of the Super Air Wipe Kit will solve the problem and keep production going. If you need help in selecting the proper size or want to know what material we would recommend for your application, contact us.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

Discovery of The Vortex Tube

There are many theories regarding the dynamics of a vortex tube and how it works. Many students have studied them in hopes of advancing the physics or as part of their undergrad studies. The man that started it all was not intentionally researching it, however.

The Vortex Tube was invented by accident in 1928, by George Ranque, a French physics student. He was performing experiments on a vortex-type pump that he had developed and noticed that warm air exhausted from one end and cold air from the other. Ranque quickly changed his focus from the pump to start a company taking advantage of the commercial possibilities for this odd little device that produced both hot and cold air, using only compressed air, with no moving parts. The company was not successful, and the vortex tube was forgotten until 1945 when Rudolph Hilsch, a German physicist, published a widely read paper on the device.

A vortex tube uses compressed air as a power source, has no moving parts, and produces hot air from one end and cold air from the other. The volume and temperature of the two air streams is adjustable with a valve built into the hot air exhaust.  Temperatures as low as -50°F (-46°C) and as high as 260°F (127°C) are possible.

Compressed air is supplied to a vortex tube and passes through nozzles that are tangent to an internal counterbore. As the air passes through it is set into a spiraling vortex motion at up to 1,000,000 rpm. The spinning stream of air flows down the hot tube in the form of a spinning shell, like a tornado (in red). The control valve at the end allows some of the warmed air to escape and what does not escape reverses direction and heads back down the tube as a second vortex (in blue) inside of the low-pressure area of the larger warm air vortex. The inner vortex loses heat and exits through the other end of as cold air.

It is thought that both the hot and cold air streams rotate in the same direction at the same angular velocity, even though they are traveling in opposite directions. A particle of air in the inner stream completes one rotation in the same time of an air particle in the outer stream. The principle of conservation of angular momentum would say that the rotational speed of the inner vortex should increase because the angular momentum of a rotating particle (L) is equal to the radius of rotation (r) times it’s mass (m) times its velocity (v).  L = r•m•v.  When an air particle moves from the outer stream to the inner stream, both its radius (r) and velocity (v) decrease, resulting in a lower angular momentum. To maintain an energy balance for the system, the energy that is lost from the inner stream is taken in by the outer stream as heat. Therefore, the outer vortex becomes warm and the inner vortex is cooled.

At EXAIR, we have harnessed the cooling power of the vortex tube, and it can be found and utilized in such products as Spot CoolersCabinet Coolers, and Vortex Tubes themselves. If you have questions about Vortex Tubes, or would like to talk about any of the EXAIR Intelligent Compressed Air® Products, feel free to contact us.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

 

Laminar Flow and Digital Flowmeters: An Explanation On How To Achieve Laminar Flow

When I see turbulent flow vs. laminar flow I vaguely remember my fluid dynamics class at the University of Cincinnati.  A lot of times when one thinks about the flow of a liquid or compressed gas within a pipe they want to believe that it is always going to be laminar flow. This, however, is not true and there is quite a bit of science that goes into this.  Rather than me start with Reynolds number and go through flow within pipes I have found this amazing video from a Mechanical Engineering Professor in California. Luckily for us, they bookmarked some of the major sections. Watch from around the 12:00 mark until around the 20:00 mark. This is the good stuff.

The difference between entrance flow, turbulent flow and laminar flow is shown ideally at around the 20:00 mark.  This length of piping that is required in order to achieve laminar flow is one of the main reasons our Digital Flowmeters are required to be installed within a rigid straight section of pipe that has no fittings or bends for 30 diameters in length of the pipe upstream with 5 diameters of pipe in length downstream.

This is so the meter is able to measure the flow of compressed air at the most accurate location due to the fully developed laminar flow. As long as the pipe is straight and does not change diameter, temperature, or have fittings within it then the mass, velocity, Q value all stay the same.  The only variable that will change is the pressure over the length of the pipe when it is given a considerable length.

Another great visualization of laminar vs. turbulent flow, check out this great video.

 

If you would like to discuss the laminar and turbulent flow please contact an Application Engineer.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

1 -Fluid Mechanics: Viscous Flow in Pipes, Laminar Pipe Flow Characteristics (16 of 34) – CPPMechEngTutorials – https://www.youtube.com/watch?v=rQcZIcEa960

2 – Why Laminar Flow is AWESOME – Smarter Every Day 208 – SmarterEveryDay – https://www.youtube.com/watch?v=y7Hyc3MRKno

 

 

When To Use The High Lift Reversible Drum Vac vs. The Reversible Drum Vac

One of my favorite TV shows growing up was Home Improvement with Tim Allen. One of the most memorable parts of the show was when Tim’s character would always state that when doing a job you need … MORE POWER!!!

In real life and within a production environment this is not always true. More often than not more power equals waste and inefficient use of the resources at hand. I know, I sound a lot like Tim Allen’s counterpart in the show, Al Borland. Well, the truth is, Al was usually right.  Here at EXAIR, we offer two different types of Reversible Drum Vac, the standard unit and the High Lift RDV.

The Reversible Drum Vac System converts a drum and dolly into a mobile pumping system.

The standard RDV will pull up to 96″ of water column when in suction mode. This is ideal for water-soluble coolants or other water-based rinses. The unit is paired with a 10′ vacuum/discharge hose to ensure optimal performance. The RDV will fill a 55-gallon drum with water in 90 seconds or less when operated at 80 psig inlet pressure. It will then empty the same drum even faster by discharging liquid at up to 166″ of water column displacement. To do both of these operations, fill or empty the drum the RDV will utilize 19 SCFM of compressed air. This is easily supplied within most industrial applications where that amount of compressed air usage can be overlooked.

EXAIR’s High Lift RDV makes cleaning out pits up to 15′ deep easy and fast.

If Binford manufactured a compressed air liquid vacuum, it would be the High Lift Reversible Drum Vac. This is the, “More Power” version of the RDV and can pull up to 180″ of water column when in vacuum mode. This can pull water-soluble coolants up to 15 feet below grade for those large machining centers that sit over the top of a coolant pit or those large footprint machines where a 20′ hose is needed to reach into and around the parts of the machine to where the coolant or liquid is housed. Another application would be for oil-based coolants or other petroleum-based oils/higher viscosity fluids. This will still discharge liquids at 166″ of water column when in positive displacement. The unit will outperform its predecessor and that comes with higher utilization of compressed air. While operating at 80 psig inlet pressure the unit will consume 43 SCFM of compressed air. This volume of air is still easily located within most industrial environments and is still less than the amount demanded by competitive units that do not offer the reversible feature of the High Lift Reversible Drum Vacs.

When it boils down to it, the High Lift Reversible Drum Vac will perform every task of the standard Reversible Drum Vac and will perform the vacuum portion of those tasks all faster due to the higher level of vacuum. When this higher level of vacuum isn’t needed, when the sump is at ground level and the coolant or liquid is around the viscosity of 50 weight motor oil or thinner then the standard RDV will work ideal for the application and would be the most efficient method to get the job done. When the liquid is higher viscosity or below ground level trying to pull it up out of a pit then the High Lift Reversible Drum Vac is the ideal tool to get the job done. Again, Al Borland had it right, more power is not always needed, sometimes it is better to keep it efficient.

If you would like to discuss your liquid vacuum application or any point of use compressed air application, please contact us. (Heck, I’ll even talk about Home Improvement if you are a fan too.)

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

 

Best of Home Improvement so 1 eo01 More Power – @shary h – https://www.youtube.com/watch?v=ts9UONUMlCg

Promos, Freebies, and Some Amazing Products

Like many companies, here at EXAIR we generally always have a promotional offering.  These rotate throughout the months and this month is no different.  The current offering involves the EXAIR Cold Gun Aircoolant Systems.

These systems help to reduce cutting fluid use, increase production speeds, increase tool life, and has helped more customers than I know.  One customer in particular is a maintenance worker from a welded tube manufacturer.  This facility had very little amount of downtime permitted due to the high efficiency and high volume of orders.  When a machine went down the maintenance team were in like a trauma team to determine the cause of failure and get it remedied to get the line back up and running. One of the biggest problems they would have is when they would have to dry machine a quick part to get the machine back up and running, this would either ruin tools or they would have to slow down the machining time to get the surface finish and dimensions they truly needed.  After talking with us the team ordered a Single Point Cold Gun Aircoolant System as these parts were generally smaller shafts or machine dogs.

They received the system in and sure enough a machine went down.  The crew went to work and once the part needed was found they got to work on their lathe trying to make a new piece.  The Cold Gun held itself straight to the headstock thanks to the integrated magnet and the flexible single point hose kit routed the cold air straight to the cutting point.  They didn’t have to fill up the liquid tank or setup the mist system on the lathe, they simply turned on the compressed air and let the lathe do the work.  They were able to take what had recently been around a three hour machine job with heavy wear on tooling to a two hour job, no finish pass was needed on the part, and their tools weren’t completely spent by the end of the job.

They got the part back into the machine, made adjustments, and then went to work getting the machine back into production.

Right now, if you would like to try out a Cold Gun Aircoolant System you can order before 12/31/2019 and use the link to order through our promotion in order to receive a free Dual Point Hose Kit with your qualified purchase.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF