Intelligent Compressed Air: Distribution Piping

air compressor

An important component of your compressed air system is the distribution piping. The piping will be the “veins” that connect your entire facility to the compressor. Before installing pipe, it is important to consider how the compressed air will be consumed at the point of use. Some end use devices must have adequate ventilation. For example, a paint booth will need to be installed near an outside wall to exhaust fumes. Depending on the layout of your facility, this may require long piping runs.  You’ll need to consider the types of fittings you’ll use, the size of the distribution piping, and whether you plan to add additional equipment in the next few years. If so, it is important that the system is designed to accommodate any potential expansion. This also helps to compensate for potential scale build-up (depending on the material of construction) that will restrict airflow through the pipe.

The first thing you’ll need to do is determine your air compressor’s maximum CFM and the necessary operating pressure for your point of use products. Keep in mind, operating at a lower pressure can dramatically reduce overall operating costs. Depending on a variety of factors (elevation, temperature, relative humidity) this can be different than what is listed on directly on the compressor. (For a discussion of how this impacts the capacity of your compressor, check out one of my previous blogs – Intelligent Compressed Air: SCFM, ACFM, ICFM, CFM – What do these terms mean?) Once you’ve determined your compressor’s maximum CFM, draw a schematic of the necessary piping and list out the length of each straight pipe run. Determine the total length of pipe needed for the system. Using a graph or chart, such as this one from Engineering Toolbox. Locate your compressor’s capacity on the y-axis and the required operating pressure along the x-axis. The point at which these values meet will be the recommended MINIMUM pipe size. If you plan on future expansion, now is a good time to move up to the next pipe size to avoid any potential headache.

Once you’ve determined the appropriate pipe size, you’ll need to consider how everything will begin to fit together. According to the “Best Practices for Compressed Air Systems” from the Compressed Air Challenge, the air should enter the compressed air header at a 45° angle, in the direction of flow and always through wide-radius elbows. A sharp angle anywhere in the piping system will result in an unnecessary pressure drop. When the air must make a sharp turn, it is forced to slow down. This causes turbulence within the pipe as the air slams into the insides of the pipe and wastes energy. A 90° bend can cause as much as 3-5 psi of pressure loss. Replacing 90° bends with 45° bends instead eliminates unnecessary pressure loss across the system.

Pressure drop through the pipe is caused by the friction of the air mass making contact with the inside walls of the pipe. This is a function of the volume of flow through the pipe. Larger diameter pipes will result in a lower pressure drop, and vice versa for smaller diameter pipes. The chart below from the “Compressed Air and Gas Institute Handbook” provides the pressure drop that can be expected at varying CFM for 2”, 3”, and 4” ID pipe.

pressure drop in pipe

You’ll then need to consider the different materials that are available. Some different materials that you’ll find are: steel piping (Schedule 40) both with or without galvanizing, stainless steel, copper, aluminum, and even some plastic piping systems are available.

While some companies do make plastic piping systems, plastic piping is not recommended to be used for compressed air. Some lubricants that are present in the air can act as a solvent and degrade the pipe over time. PVC should NEVER be used as a compressed air distribution pipe. While PVC piping is inexpensive and versatile, serious risk can occur when using with compressed air. PVC can become brittle with age and will eventually rupture due to the stress. Take a look at this inspection report –  an automotive supply store received fines totaling $13,200 as a result of an injury caused by shrapnel from a PVC pipe bursting.

Steel pipe is a traditional material used in many compressed air distribution systems.  It has a relatively low price compared to other materials and due to its familiarity is easy to install. It’s strong and durable on the outside. Its strength comes at a price, steel pipe is very heavy and requires anchors to properly suspend it. Steel pipe (not galvanized) is also susceptible to corrosion. This corrosion ends up in your supply air and can wreak havoc on your point-of-use products and can even contaminate your product. While galvanized steel pipe does reduce the potential for corrosion, this galvanizing coating can flake off over time and result in the exact same potential issues. Stainless Steel pipe eliminates the corrosion and rusting concerns while still maintaining the strength and durability of steel pipe. They can be more difficult to install as stainless steel pipe threads can be difficult to work with.

Copper piping is another potential option. Copper pipe is corrosion-free, easy to cut, and lightweight making it easy to suspend. These factors come at a significant increase in costs, however, which can prevent it from being a suitable solution for longer runs or larger ID pipe installations. Soldering of the connecting joints can be time consuming and does require a skilled laborer to do so, making copper piping a mid-level solution for your compressed air system.

Another lightweight material that is becoming increasingly more common in industry is aluminum piping. Like copper, aluminum is lightweight and anti-corrosion. They’re easy to connect with push-to-lock connectors and are ideal for clean air applications. Aluminum pipe remains leak-free over time and can dramatically reduce compressed air costs. While the initial cost can be high, eliminating potential leaks can help to recoup some of the initial investment. Aluminum pipe is also coated on the inside to prevent corrosion. While an aluminum piping system may be the most expensive, its easy installation and adaptability make it an excellent choice.

It can be easy to become overwhelmed with the variety of options at your disposal. Your facility layout, overall budget, and compressed air requirements will allow you to make the best choice. Once you’ve selected and installed your distribution piping, look to the EXAIR website for all of your point-of-use compressed air needs!

Tyler Daniel
Application Engineer
E-mail: TylerDaniel@exair.com
Twitter: @EXAIR_TD

Basics of Static Electricity

Here in the Northern Hemisphere, we are in the middle of winter and that means extremely dry air, and frequent shocks when reaching for a door knob after walking across a carpeted surface.  While a shock is mildly uncomfortable and can be annoying to us, the presence of static electricity in an industrial manufacturing process can be much more problematic.

Problems that static cause range from operator discomfort to increased downtime to quality issues.  Dust can cling to product, product can cling to itself, rollers, frames, or conveyors. Materials may tear, jam, curl and sheet fed items can stick and mis-feed. Hazardous sparks and shocks can occur, possibly damaging sensitive electronics.

EXAIR has put together a useful tool, the Basics of Static Electricity white paper with Interactive Regions to help a person learn more about static.

Basics of Static Electricity

 

Topics covered include Electron Theory, Causes of Static Electricity, Triboelectric Series chart, and Types of Static Generation.  Also, the white paper covers the areas of How to Control Static Charge Buildup, Determining the Source of the Static Buildup, Eliminating or Minimizing the Source Causing the Buildup, and Treating Static Buildup.

The Treating Static Buildup is a comprehensive review of the EXAIR Static Elimination products and how each technology is best applied to different processes and applications.

To receive your copy of the Basics of Static Electricity white paper, click the photo above or the link here.

If you would like to talk about static electricity or any of the EXAIR Intelligent Compressed Air® Products, 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

EXAIR Siphon Fed Atomizing Nozzles: Overview

No Drip Atomizing Family

In today’s market, the cost of consumable products are on the rise; especially with paints, oils, and yes, even the cost of water.  You can help alleviate some of that cost by being more effective in spraying with less liquid.  The EXAIR Atomizing Nozzles can accomplish both of these objectives.  By using compressed air, the liquid can be sheared into smaller micron-sized droplets.  As a reference, if the diameter of a particle is reduced by one-half, this will multiply the number of droplets by eight.  With a smaller diameter, it will increase the surface area and coverage of the droplets; thus, requiring less liquid in your application.  In combination with a variety of spray patterns, you can accurately target the liquid onto the product instead of around the product.  EXAIR manufactures three families of Atomizing Nozzles; Internal Mix, External Mix, and the Siphon Fed.  In this blog, I will be discussing the Siphon Fed Atomizing Nozzles.

Siphon Fed Nozzles

When no liquid pressure is available, the Siphon Fed Atomizing Nozzles will create a vacuum in the liquid line to draw the fluid into the nozzle.  This action is done by the unique design of the air cap.  As the velocity of the air passes through the air cap, a low pressure is created on the liquid side by a venturi.  These Atomizing Nozzles can draw liquid from a suction height of 36” (91 cm) or can be gravity fed from a distance of 18” (46 cm).  They are manufactured from stainless steel for durability and corrosion resistance.  The Siphon Fed models can spray viscous fluids up to 200 centipoise, and are used in many applications like washing, coating, cooling, quenching, and dust control.

EXAIR carries three different body sizes in 1/8” NPT, ¼” NPT, and ½” NPT ports; so, you can create a light mist or a monsoon.  The maximum liquid flow rate through each body size is controlled by the air cap and liquid cap.  These caps are easily interchangeable for each body size to modify the spray patterns, control the amount of fluid, and reduce any downtime if cleaning is required.  The amount of liquid to be applied is easily adjusted by the siphon height, inlet pressure, and the liquid adjusting stem.  So, you can dial in the exact amount of fluid required for your process to eliminate any waste or excess. They are very compact and easy to install.  We carry mounting brackets for each size to allow for easy mounting and positioning for efficacy.   Versatility is very important in saving, applying, and spraying costly fluids, and the Siphon Fed Atomizing Nozzles have it.

No Drip Siphon Fed Round Pattern Atomizing Nozzle

To reduce waste even more, EXAIR has a No Drip option.  This patented design is used to keep the expensive liquid from dripping out of the Atomizing Nozzles.  When the compressed air is turned off, a valve inside the body will create a seal on the liquid side.  For delicate applications, the unwanted drips will not occur with the No Drip option and ruin the finish of your product.  This option also enhances the function of the Siphon Fed Atomizing Nozzle in intermittent processes.  It will keep the liquid inside the body of the nozzle; so, when air pressure is applied, the Atomizing Nozzle will give an instant spray.

With an Electronic Flow Control (EFC), you can automate your system to only spray parts when the product is under the Atomizing Nozzle.  The EFC comes with a solenoid valve, a timing circuit, and a photoelectric sensor.  With the solenoid valve on the air pressure side, the Atomizing Nozzle can reach speeds up to 180 cycles per minute.  The minimum air pressure required to open the No Drip valve is 30 PSIG (2.1 bar) for the ¼” NPT and the ½” NPT port sizes, and 20 PSIG (1.4 bar) for the 1/8” port size.  Unlike some manufacturers, there is no need to run a separate compressed air line to operate the no drip function.  The Siphon Fed Atomizing Nozzles with the No Drip options are efficient, effective, and flexible without any drips.

If you need to maximize the liquid dispersion and minimize liquid consumption, the EXAIR Atomizing Nozzles are the products to use.  Instead of researching the requirements for liquid pumps or pressure pots, the Siphon Fed Atomizing Nozzle can draw the liquid through the feed line and start spraying.  It can help reduce the cost of your project as well as save you money on your consumable products.  If you have an application involving liquid spraying, an Application Engineer at EXAIR can help determine the correct model for you.

John Ball
Application Engineer

Email: johnball@exair.com
Twitter: @EXAIR_jb

More Efficient Compressed Air Use Could Lead To Energy Rebates

The use of compressed air can be found in almost any industry and is often referred to as a “fourth utility” next to water, gas and electric. The generation of compressed air accounts for approximately 1/3 of all energy costs in an industrial facility, in many cases, it’s the largest energy user in an industrial plant. With an average cost of $ 0.25 per every 1,000 SCF used, compressed air can be expensive to produce so it is very important to use this utility as efficiently as possible.

Utility companies recognize the benefit of using engineered products to reduce compressed air usage, like the ones manufactured by EXAIR, and offers rebate incentives for making a switch. Our local utility provider here in Cincinnati, Duke Energy, offers a $ 20 incentive for each replacement engineered nozzle.

 

Our Model # 1100SS 1/4″ FNPT and Model # 1101SS 1/4″ MNPT Super Air Nozzles

In their specification, the nozzle must meet a certain volumetric flow rate (SCFM) at 80 PSIG operating pressure for a given pipe size. For example, when looking at a 1/4″ nozzle, the flow rate must be less than or equal to 17 SCFM when operated at 80 PSIG. Our most popular nozzles for “general” blowoff applications would be our Model # 1100 (1/4″ FNPT) or our Model # 1101 (1/4″ MNPT) Super Air Nozzles. These nozzles require 14 SCFM @ 80 PSIG so this would be the ideal solution to reduce the air demand and take advantage of the rebate.

Here at EXAIR, much of our focus is to improve the overall efficiency of industrial compressed air operating processes and point of use compressed air operated products. If you’d like to contact one of our application engineers, we can help recommend the proper engineered solution to not only save on your compressed air usage but also assist with possible energy rebates available in your area.

Justin Nicholl
Application Engineer
justinnicholl@exair.com
@EXAIR_JN

 

 

The Case For The EXAIR Super Ion Air Knife

One of the best ways, in industry, to generate a static charge is to roll or unroll non-conductive materials such as polymer films, plastic sheet, etc. It’s common to see static charges well in excess of 10,000 volts in such operations, like the one I discussed with a customer recently.

The separation of the non-conductive surfaces (like when this plastic film is unrolled) is capable of generating an incredible amount of static charge. Here are two examples showing 12,400 and 16,900 volts.

One of the best ways, in industry, to dissipate a static charge is to use ionized air.  There are different methods of doing this; one of the most popular is to effect a Corona discharge, via a high voltage, low amperage electric current.  This is precisely what EXAIR’s Static Eliminators provide: a Corona discharge produces a bulk of both (+) and (-) ions in the enormous volume of high velocity air flow generated.  When these (+) and (-) ions flow onto a surface charged with (-) and (+) ions, they cancel each other out, leaving a net neutral charge.  Static, eliminated!

THE best way to accomplish this is the EXAIR Super Ion Air Knife.

From small bottles to wide films, EXAIR Super Ion Air Knives come in a variety of lengths to meet the needs of most any static dissipation application.

By combining an Ionizing Bar with a Super Air Knife, as Super Ion Air Knife provides rapid static elimination AND blow off of any dust, chips, or debris that was being statically held.  The laminar curtain of ionized air not only maximizes the rate of static dissipation, but is also ideal for stripping/sweeping away any debris, leaving a clean, static-free surface.  No more jamming, tearing, nuisance shocks to operators, dust attraction, or any of the other host of problems associated with static electricity.

The ionized air flow can be precisely regulated to whatever level it takes to get the job done.  At 100psig, the powerful, high velocity blast will dissipate 5,000 volts of static charge in 0.18 seconds.  If the material is fragile, or if that kind of air flow might disrupt the process, it’s not a big deal…even at 5psig supply pressure, that same 5,000 volts is dissipated in 0.40 seconds.  That’s how it works on the plastic roll above – with just a whisper of ionized air flow from a Super Ion Air Knife, they consistently reduce the resultant static charge to less than 400 volts…far below the threshold for the nuisance shocks they wanted to avoid.

They’re on the shelf in lengths from 3 inches to 9 feet long, and we can make custom lengths in three days after receipt of an order.  The 115/230VAC GEN4 Power Supplies are available with 2 or 4 outlets, to energize any 2 or 4 EXAIR GEN4 Static Eliminators.

Versatile. Efficient. Effective. Quiet. Safe.  And, readily available.  If you’d like to discuss a static problem, give me a call.

EXAIR’s Flat Nozzles: Safe, Reliable, and Efficient

Here on the EXAIR Blog we frequently discuss dead-end pressure as explained in OSHA Standard 1910.242(b). This directive states that the when compressed air is used for cleaning purposes, the dead-ended pressure must not exceed 30 psig. When pressures greater than this occur, there is potential for an air embolism. This animation shows and explains how an air embolism can affect the body.

EXAIR’s Flat Nozzles adhere to this OSHA directive. The Flat Nozzles consist of three primary components: the body, the cap, and the shim. The thickness of the shim will dictate the flow and force through the nozzle and can be easily adjusted. The cap slightly protrudes from the body and shim, creating a gap when it is pressed up onto the skin. By ensuring that there is always an avenue for that air to escape, there is no potential for it to be dead-ended.

2fsanfam2
From top to bottom: Model 1126, 1126SS, 1122, and 1122SS

EXAIR’s flat nozzles are available in two sizes: 1” and 2”. Each size has a shim set that can be purchased for adjusting both the flow and force from the nozzle. These nozzles are available in both zinc/aluminum alloy as well as 316 grade Stainless Steel. They can be used by themselves, installed on our Safety Air Guns, or in conjunction with our Stay Set Hoses that allow for easy re-positioning.

You may have seen (or used) the plastic flat nozzles that come in a variety of different colors. EXAIR’s flat nozzle is a safe, efficient, and more robust replacement that will maintain a similar airflow pattern at a dramatically reduced operating cost. Where plastic nozzles may become damaged or break off, the rigid construction of EXAIR’s Flat Nozzle will not. In addition to be safe, durable, and reliable, EXAIR’s flat nozzles also offer a reduced sound level compared to these styles of nozzle. Reducing sound is another directive that OSHA 29 CFR 1910.95 covers. If you’re using an unsafe nozzle in your facility, OSHA can quickly begin assessing fines for each violation. They don’t announce their visits beforehand, so make sure you do your due diligence and assess your compressed air blowoff products yourself!

2san_blowaway
EXAIR 2″ Flat Super Air Nozzle “blows” away the competition!

If you would like to discuss how to make your compressed air use safer and more efficient, give us a call. Our team of highly-trained Application Engineers is standing by, ready to help you make the switch to an Intelligent Compressed Air Product.

Tyler Daniel
Application Engineer

E-mail:TylerDaniel@exair.com
Twitter:@EXAIR_TD

People of Interest: Robert Boyle – January 25, 1627 – December 31, 1691

Robert Boyle was born on January 25, 1627 in Lismore Castle, County of Waterford, Ireland.  He was an Anglo-Irish natural philosopher, chemist, physicist and dabbled in many other areas of study. He published the book The Sceptical Chymist in 1661, and many consider him and his work as the foundation of modern chemistry.  He was a very devout Anglican, and published numerous works in this area as well.

Robert Boyle

One of Boyle’s most famous discoveries was to become the first of the gas laws, relating the pressure of a gas to its volume. With Robert Hooke, a young university student as his laboratory assistant, Boyle began experimenting with air.  Together they made their first great discovery, now known as Boyle’s Law.

J-Tube 2
Boyle used a ‘J’ Tube – Sealed on the Short End, and Open at the Long End

The experiment was performed using a ‘J’ shaped glass tube sealed on the shorter leg, and open to atmosphere on the longer leg.  Quicksilver (mercury) was poured into the tube, such that the level was equal on each side. The volume of the trapped air was noted. Additional mercury was poured into the tube and it was observed that the mercury did not stay level, and measurements of the heights on each tube leg were recorded.  The height difference of the mercury is effectively a measure of the pressure of the trapped air. Boyle, through the experiment and the data,  discovered a relationship between the volume and the pressure of air.  The data as published, is shown below.

Boyle's Data

Boyle noticed the pressure times the volume of air for the initial condition equaled the pressure times the volume at any other mercury height.

Known as Boyle’s Law – P ∝ 1/V,      pressure is proportional to the inverse of the volume

Alternately, PV = k,       pressure times volume is equal to a constant

For comparing the same substance under two different sets of conditions, the law can be expressed as P1V1 = P2V2

Of note is that Boyle’s Law, combined with Charles’s law and Gay-Lussac’s Law formed the combined gas law, and in combination with Avogadro’s law is the basis for the ideal gas law – PV=nRT, which include temperature, the amount of the substance, and the ideal gas constant to the mix.

It is noted that Boyle credited fellow scientist Richard Towneley for making the connection between the pressure of a gas and volume, but Boyle’s experiments and observations using the ‘J’ tube confirmed Towneley’s predictions, and the rest as they say is history.

If you would like to talk about compressed air or any of the EXAIR Intelligent Compressed Air® Products, 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

Experiment Data from the book New Experiments Physico-Mechanicall, Touching the Spring of the Air, and Its Effects (1660)