Is PVC Pipe Alright to Use with Compressed Air?

A question arises every now and then on whether or not PVC pipe, yes the stuff from your local hardware store that says it is rated for 200 psi, is safe to use as compressed air supply line.   The answer is always the same,  NO! OSHA agrees – see their statement here.

Schedule 40 PVC pipe is not designed nor rated for use with compressed air or other gases.  PVC pipe will explode under pressure, it is impacted significantly by temperature and can be difficult to get airtight.

PVC pipe was originally designed and tested for conveyance of liquids or products that cannot be compressed, rather they can be pressurized.   The largest concern is the failure method of the piping itself.   When being used with a liquid that cannot be compressed, if there is a failure (crack or hole) then the piping will spring a leak and not shatter.   When introducing a compressed gas, such as compressed air, if there is a failure the method ends up being shrapnel.  This YouTube video does a good job of illustrating how the pipe shatters.

While it may seem that it takes a good amount of pressure to cause a failure in the pipe, that is often not the case.  I have chatted with some local shop owners who decided to run PVC as a quick and cheap alternative to get their machines up and running.

They each experienced the same failures at different points in time as well.  The worst one was a section of PVC pipe installed over a workbench failed where an operator would normally be standing. Luckily the failure happened at night when no one was there.  Even though no one got injured this still caused a considerable expense to the company because the compressor ran overnight trying to pressurize a ruptured line.

Temperature will impact the PVC as well. Schedule 40 PVC is generally rated for use between 70°F and 140°F (21°-60°C). Pipes that are installed outside or in non temperature controlled buildings can freeze the pipes and make them brittle.

If you haven’t worked with PVC before or do not let the sealant set, it can be hard to get a good seal, leading to leaks and a weak spot in the system.

The point of this is the cheapest, quick, and easy solutions are more often , the ones that will cost the most in the long run.

If you would like to discuss proper compressed air piping and how to save compressed air on your systems, please contact us.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

 

Image courtesy of: Dennis Hill, Creative Commons License

Static Elimination for Hose, Pipe, Extrusion, Cable and Wire

EXAIR’s  Gen4 Super Ion Air Wipe provides a uniform 360 degree ionized air stream that clamps around a continuously moving part to eliminate static electricity and contaminants. It is ideal for removing dust, particulates and personnel shocks on pipe, cable, extruded shapes, hose, wire and more. This engineered product has undergone independent laboratory tests to certify it meets the rigorous safety, health and environmental standards of the USA, European Union and Canada that are required to attain the CE and UL marks. It is also RoHS compliant. New design features include a metal armored high voltage cable to protect against abrasion and cuts, a replaceable emitter point, integrated ground connection and electromagnetic shielding.

g4siaw_3mb

The Gen4 Super Ion Air Wipe uses a small amount of compressed air to entrain high volumes of ambient air. Two shockless ionizing points powered by our Gen4 UL Component Recognized 5kV Power Supply fills the air stream with static eliminating ions. That airflow impacts the surface of the material running through the air wipe and neutralizes the charge.

The Gen4 Super Ion Air Wipe, which compliments EXAIR’s complete line of Gen4 Static Eliminators, has an aluminum construction that is lightweight and easy to mount using the tapped holes provided. Two sizes include a 2 inch (51mm) diameter and a 4 inch (102mm). There are no moving parts to wear out. Visit EXAIR.com to see the entire Gen4 Static Eliminator product line and 1/2 inch through 11 inch Super Air Wipes for applications without static.

Purchase a Gen4 Super Ion Air Wipe through our online promotional before March 31st, 2019 and receive a fee AC Sensor.

absesqmaster_300sq

To discuss your application and how an EXAIR Intelligent Compressed Air Product can help your process, feel free to contact EXAIR and myself or one of our Application Engineers can help you determine the best solution.

Jordan Shouse
Application Engineer
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Twitter: @EXAIR_JS

Sanitary Flange Line Vacs for Bulk Conveying

Piping systems have been a hallmark of human civilization for almost as long as people have been living in community with each other. Evidence of complex earthen pipe systems, with flanged fittings & asphalt sealants, date to 2700 BC. These were used for crop irrigation, potable water distribution, and wastewater removal in ancient civilizations from the Mediterranean to the Far East.

Over the centuries, new ways to use pipe led to new ways to make pipe.  Scientists and engineers figured out ways to make pipe stronger, lighter, cheaper, and in a variety of materials.  One of the more recent milestones is the development of sanitary piping and fittings.  The stringent cleanliness controls in certain industries (food and pharmaceutical, I’m looking at you) require highly corrosion resistant materials of construction.  The inside & outside surfaces of the pipe have to be finely finished so that they can be thoroughly and positively cleaned, with no crevices, “nooks & crannies,” etc., for material to gather or cling.  And since regular cleaning & sterilization is performed, the fittings must be able to be made & unmade in a manner that still provides for positive sealing when the system is restored to operation.

EXAIR Line Vac Air Operated Conveyors have always been well suited for applications like this.  With their open, unobstructed throats and smooth bores, they’re intuitively easy to clean, by design.  And we’ve made them, for years, in Type 316 Stainless Steel – the preferred material of construction for many food and pharmaceutical applications.  Many users in these industries were able to install them in sanitary piping systems by welding the flanges on our Stainless Steel Line Vacs, or by installing adapters on our Threaded Stainless Steel Line Vacs.

In the spring of 2017, EXAIR released the Sanitary Flange Line Vac with those same users in mind – eliminating the need to weld or thread flanges onto existing products.  They feature the same conveyance power as our Stainless Steel Line Vacs, and can even be modified to meet Heavy Duty Line Vac performance, if needed.  There are four sizes: 1-1/2″, 2″, 2-1/2″, and 3″…which covers the most popular size range of sanitary pipe systems.

While the sanitary piping systems are certainly most often found in those cleanliness-critical food & pharma type applications, other users incorporate them because of the smooth, continuous bore of the pipe and fittings, as opposed to a threaded pipe system, where the OD of the pipe threads into the ID of the fittings, causing a “step” in the throughput.  Because sanitary fittings mate via face-to-face flange seals, this eliminates that “step” which can make for a catch-point for certain items.  It’s for this very reason that a popular ammunition manufacturer uses sanitary pipe systems to convey shell casings…because they tumble with such turbulence in the air flow, they are especially prone to hanging up on any kind of catch-point.  So, they use sanitary piping & fittings, long radius elbows, and EXAIR Model 161150-316 1-1/2″ Sanitary Flange Line Vacs.

Air conveying of certain items, like these ammo shell casings, can be prone to clogging or jamming in systems where pipe, hose, and/or fittings are inserted into each other, creating catch-points.

EXAIR has a wide selection of engineered compressed air products that are “textbook” solutions for certain applications, but also make perfect sense for use in places you might not have thought of.  If you have a bulk material conveyance operation you’d like to discuss, give me a call.

Russ Bowman
Application Engineer
EXAIR Corporation
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Shells photo courtesy of hydropeek  Creative Commons License

The Case For The EXAIR Super Air Wipe

If you’ve ever used an air gun to blow something off, you’re familiar with the cleaning ability of compressed air.  If you can get the whole object blown off from where you’re standing, there really is no substitute…but what if you need to get to the other side…or sides?

Even if your product is not on fire, you probably wouldn’t want to “limbo” under it with an air gun…

This is where the EXAIR Super Air Wipe comes in…they allow you to blow a continuous, uniform 360° air stream, all around your product.  Consider their benefits:

*Sizes: the Super Air Wipe’s compact ring design means it won’t take up a lot of room; you just need a few inches, in any direction, to install one.  We stock them in eleven sizes, from 11″, all the way down to our brand-new 3/8″ diameter.

*Durability:  All EXAIR Super Air Wipes are assembled with stainless steel shims and hardware.  Models up to 4″ come with a rugged, stainless steel wire braided hose, connecting the two halves for compressed air supply.

The aluminum Super Air Wipe is available in 11 sizes; the stainless steel Super Air Wipe comes in 5 sizes…all from stock.

*Ease of installation:  Smaller sizes can be supported by the compressed air supply line, if a pipe is used and threaded into the connector hose’s 1/4 NPT port.  Larger sizes can likewise be adequately supported with pipe to both halves. All models have a bolt circle of 1/4″-20 tapped holes for more permanent and rigid mounting.  The split ring design is another key feature:

Simply open the two halves, and clamp them around your product…no threading!

*Corrosion resistance: Depending on the environment in which the Super Air Wipe will be installed, we offer them with aluminum (3/8″ – 11″ sizes) or stainless steel (3/8″ – 4″ sizes) bodies.

*Temperature rating: Aluminum Super Air Wipes are good to 400°F (204°C) and stainless steel models are good to 800°F (427°C.)

*Range of operation: We install a 0.002″ thick shim in all stock Super Air Wipes; this is suitable for a wide range of typical industrial/commercial blow off applications…a Pressure Regulator can then be used to “dial in” the air flow precisely to meet specific needs.  If a job calls for higher force & flow, additional 0.002″ shims can be installed.  Shim Sets come with the Super Air Wipe Kits, or individual shims can be ordered separately.

*Performance: Before the Super Air Wipe, a ring of nozzles was commonly used.  In fact, they still are, but we’re trying to fix that, at every opportunity we come across.  Problem with those is, it’s hard to get an even air flow all around, which leads to inconsistent blow off.  They can also be loud & inefficient, as we’ve found in numerous Efficiency Lab tests and Case Studies, like this one…

These wasteful and loud modular plastic tube blow offs…
…were replaced with EXAIR Super Air Wipes. 24 such replacements netted the customer an annual compressed air cost savings of over $13,000.00.

…and this one…

Implementing a Super Air Wipe salvaged a $30,000 job for this customer. Click on the picture to read all about it in our Case Study Library (registration required.)

Do you have a challenging blow off application that you need help with?  Call us to find out how an EXAIR Super Air Wipe (or another one of our Intelligent Compressed Air Products) can be a simple, quick & easy solution.

Super Air Wipes Help a Swiss CNC Machine to be More Accurate

Precision Required

As machined parts require tighter tolerances, machine shops are starting to look at Swiss-type CNC machines.  These types of machines are extremely accurate and very fast in producing small parts.  But in order to reach that level of accuracy, the bar stock may have to be pre-treated by a centerless grinder.

Our customer was using Swiss-type CNC machines with guide bushings to produce a very tight-tolerance part.  Because they were using guide bushings, the outside diameter of the bar stock had to be smooth and concentric.  This helps to reduce any vibration when machining.  A centerless grinder was used to accomplish this.  The bar stock that they used was 10 feet long and it was placed into a bar feeder.  They had to grind the bar to an outer diameter of 30mm with a surface finish of 32Ra.  As they were loading the bar stock, they noticed that the surface finish was scuffed and marred.  This was enough to affect the machining process and not meet the tolerance standard.

As they reviewed the possible causes, they found that after the bar was ground, some grinding remnants were sticking to the outside of the bar.  As the rods were leaving the grinder and placed onto a roller-type conveyor, the oily film and metal shavings were sticking to the rollers.  This would scrape and mark the rods as they traveled along the conveyor toward the Swiss-type machining center.  As an attempt to remove this debris, they attached two copper tubes to blow compressed air onto the top and bottom of the bar.   Not only was this loud and inefficient, it was not effective.  They still had a dirty line along the sides of the rod that remained.  They contacted EXAIR to see if we could help them with this dilemma.

In order to get a consistent blow-off force around the entire circumference of the rod, EXAIR Air Wipes were engineered to be an ideal solution for this kind of problem.  I recommended the model 2482 Standard Air Wipe Kit.  The Standard Air Wipe is designed to blow compressed air in a 360 degree flow pattern.  This air pattern is directed at a 30 degree angle toward the center to blow the debris off of the bar stock.  The Coanda effect maximizes the entrainment of ambient air into the compressed air.  This makes the unit very efficient and powerful.  The model 2482 Standard Air Wipe has an I.D. of 2” (51mm) which gives it enough clearance for the 30mm bar stock.  It can be mounted easily near the exit of the centerless grinder to keep the grinding remnants inside the machine.  The kit includes a filter, regulator, and shim set.  The filter will remove contaminants from the compressed air system to keep from introducing any new grime and to keep the inside of the Air Wipe clean and functional.  The shim set and regulator provide the ability to adjust the air to the ideal force level and remove any debris from the surface of the bar.

Standard Air Wipe with Shim Set

As they removed their home-made copper tubes and attached the Standard Air Wipe, they noticed some great improvements.  The dark lines of debris previously along the sides of the bar stock were gone.  The surface was clean around the entire circumference of the bar.  The customer also noticed that the Standard Air Wipe was much quieter than their home-made solution, as it only has a decibel rating of 77 dBA.  As an added benefit, the Standard Air Wipe was using much less compressed air than the copper tubes.  This is due to its design to maximize the amplification ratio.  With more of the “free” ambient air than the compressed air being moved over the target area, it will save money in compressed air usage.  The ROI could be less than four months.

If you have any items that need to have a 360 degree blowing pattern, you can contact an Application Engineer at EXAIR to see if a Standard Air Wipe could work for you.

John Ball
Application Engineer

Email: johnball@exair.com
Twitter: @EXAIR_jb
Picture: External-Micrometer-Screw-Gauge by Emilian Robert Vicol.  Creative Commons license

Super Air Wipe Cools, Cleans and Dries Extruded Shapes

We have many customers that use the manufacturing process of extrusion to make their various type of products.  EXAIR has an Intelligent Compressed Air Product that works very well with these processes to provide a drying, blowoff and cooling function.

Many types of products are produced via the process of extrusion, which is to shape (as metal or plastic) by forcing through a die.  There are many advantages to the extrusion process, including it being a continuous operation, it runs at high speeds, is good for high volume and low production costs, as well as many other factors.

The extrusion process typically requires heating of the metal billet or melting of the plastic to a high enough temperature to allow it to flow and be shaped as it it forced through the die. After the product has passed through the die and has been shaped it must be cooled and this is usually achieved by passing the it through a water bath.  Once the material has been cooled, it needs to be dried to remove the moisture, before the extrusion enters the next stage of processing, like getting cut to length or printed upon.

The EXAIR Super Air Wipe is ideal for blowoff, drying, cleaning and cooling of continuous materials such as extrusions, pipe, cable and more.

saw_2-2

The Super Air Wipe has a split design which offers easy clamping around the surface of the material, eliminating the need for threading. All Super Air Wipe models include stainless steel screws and shims.  Stainless Steel wire braided hose which is plumbed to each half, is included on sizes up to 4″ to simplify installation and plumbing. Aluminum models are rated to 400°F and the stainless steel models for temperatures up to 800°F.  Models are available in size from 1/2″ to 11″ Throat Diameters.

The Super Air Wipe provides a uniform, 360° air stream that is ideal for drying and cooling of extruded materials.

To discuss your application and how an EXAIR Super Air Wipe can benefit you extrusion process, feel free to contact EXAIR and myself or one of our Application Engineers can help you determine the best solution.

Brian Bergmann
Application Engineer

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Twitter: @EXAIR_BB

Consider these Variables When Choosing Compressed Air Pipe Size

Here on the EXAIR blog we discuss pressure drops, correct plumbing, pipe sizing, and friction losses within your piping system from time to time.   We will generally even give recommendations on what size piping to use.  These are the variables that you will want to consider when selecting a piping size that will suit your need and give the ability to expand if needed.

The variables to know for a new piping run are as follows.

  • Flow Rate (SCFM) of demand side (products needing the supplied compressed air)
  • System Pressure (psig) – Safe operating pressure that will account for pressure drops.
  • Minimum Operating Pressure Allowed (psig) – Lowest pressure permitted by any demand side point of use product.
  • Total Length of Piping System (feet)
  • Piping Cost ($)
  • Installation Cost ($)
  • Operational Hours ( hr.)
  • Electical Costs ($/kwh)
  • Project Life (years) – Is there a planned expansion?

An equation can be used to calculate the diameter of pipe required for a known flow rate and allowable pressure drop.   The equation is shown below.

A = (144 x Q x Pa) / (V x 60 x (Pd + Pa)
Where:
A = Cross-Sectional are of the pipe bore. (sq. in.).
Q = Flow rate (cubic ft. / min of free air)
Pa = Prevailing atmospheric absolute pressure (psia)
Pd  = Compressor discharge gauge pressure (psig)
V = Design pipe velocity ( ft/sec)

If all of these variables are not known, there are also reference charts which will eliminate the variables needed to total flow rate required for the system, as well as the total length of the piping. The chart shown below was taken from EXAIR’s Knowledge Base.

Piping
Airflow Through 1/4″ Shed. 40 Pipe

Once the piping size is selected to meet the needs of the system the future potential of expansion should be taken into account and anticipated for.   If no expansion is planned, simply take your length of pipe and start looking at your cost per foot and installation costs.    If expansions are planned and known, consider supplying the equipment now and accounting for it if the additional capital expenditure is acceptable at this point.

The benefits to having properly sized compressed air lines for the entire facility and for the long term expansion goals makes life easier.   When production is increased, or when new machinery is added there is not a need to re-engineer the entire system in order to get enough capacity to that last machine.   If the main compressed air system is undersized then optimal performance for the facility will never be achieved.   By not taking the above variables into consideration or just using what is cheapest is simply setting the system up for failure and inefficiencies.   All of these considerations lead to an optimized compressed air system which leads to a sustainable utility.

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