Tag: pressure

Common Compressed Air Drawing Symbols

Published on by John BallLeave a comment
The symbols on top denote the EXAIR products below (left to right): Flowmeter, Pressure Gauge, and Solenoid Valve

When it comes to drawings and diagrams to map out a process system, the piping and instrumentation diagrams (P&ID) are a great way to situate and find components.  They use different symbols to represent the types of products, the layout of the system, installation, and process flow.  These standard symbols are created by ANSI or ISO.  They are used in electrical, hydraulic, and pneumatic processes. I will cover some pneumatic symbols and the process flow in this blog.

A colleague, Russ Bowman, wrote an article about “Knowing Your Symbols Is Key To Understanding Your Drawings”.  As a reference, air compressors are the start of your pneumatic system, and there are different types as represented by the symbols below.

Air compressors are considered the fourth utility in industries because they use so much electricity, and they are inefficient.  So, you need to use the compressed air as efficiently as possible.  As a typical pneumatic system, the air compressors, receiver tanks and compressed air dryers would be on the supply side.  The distribution system, or piping, connects the supply side to the demand side.  This symbol is represented by a simple line.  The demand side will have many different types of pneumatic devices.  Since there are so many, ANSI or ISO has created some common types of equipment.  But if there isn’t a symbol created to represent that part, the idea is to draw a basic shape and mark it.

From top left, and then down: Automatic Drain Filter Separator, Oil Removal Filter, Pressure Regulator, and Super Air Knife

As an example, if I were to do a P&ID diagram of the EXAIR Super Air Knife Kit, it would look like the above diagram.  The kit will include the Super Air Knife with an Automatic Drain Filter Separator and a Pressure Regulator.  The Filter Separator is a diamond shape and, since it has an Automatic Drain, a triangle is placed at the bottom.  Filter Separators are used to clean the compressed air and keep the Super Air Knife clean.  The Automatic Drain will discard water and oil from the filter bowl when it accumulates over the float.  The next item is the pressure regulator, which is represented by a rectangle with an adjustment knob to “dial in” the desired blowing force.  And at the end, we drew a rectangle, which represents a Super Air Knife, as marked.

Using the P&ID diagram for the process flow is important.  You noticed that the Filter Separator would come before the Pressure Regulator.  This is significant when installing this system.  Did you remember the statement above about “using your compressed air as efficiently as possible”?  Inefficiencies come from two basic areas; pressure drop and overusing your compressed air.  Pressure drop is based on velocity.  The lower the velocity, the lower the pressure drop.  For the second part about overusing compressed air, the Pressure Regulator will help.  You want to use the lowest amount of air pressure as possible for the Super Air Knife to “do the job”.  The lower air pressure will use less compressed air in your operation.

EXAIR products are engineered to be safe, efficient, and effective in your compressed air system.  If you need help to place them in your P&ID diagrams, an Application Engineer can help you.  It is important to have the pneumatic devices in the proper place.  If you want to efficiently use your compressed air, you can use EXAIR products for your blow-off devices.  We have been doing this for a long time.

John Ball
Application Engineer
Email: johnball@exair.com
Twitter: @EXAIR_jb

Compressed Air and Pressure Drop: Explained

Published on by Tyler DanielLeave a comment

A critical component to optimal performance of any compressed air operated product is ensuring sufficient compressed air flow. Simply put, inadequate air flow won’t allow you to get the job done.

 As compressed air moves through the distribution system, it encounters friction inside the walls of the pipe, tube, hose, etc. The diameter of the pipe, length, number of direction changes, and finished surface of the inner wall all play a part in this. A drop in air pressure will occur as a result of this friction. In addition to pressure drops experienced due to the distribution system, they can also occur at the point of use. If the line is undersized, this pressure drop will be great enough to impact the performance of the product. 

When designing and maintaining your compressed air system, pressure measurements should be taken at varying points to identify (and fix) any issues before they create a greater problem down the road. According to the Compressed Air Challenge, these are the places you should take regular pressure measurements to determine your system operating pressure:

  • Inlet to compressor (to monitor inlet air filter) vs. atmospheric pressure
  • Differential across air/lubricant separator
  • Inter-stage on multistage compressors
  • After-cooler
  • At treatment equipment (dryers, filters, etc.)
  • Various points across the distribution system
  • Check pressure differentials against manufacturers’ specifications. If high pressure drops are noticed, this indicates a need for service.

*More recent compressors will measure pressure at the package discharge, which will include the separator and after-cooler.

Once you’ve taken these measurements, simply add the pressure drops measured and subtract that value from the operating range of your compressor. That figure is your true operating pressure at the point of use.

If your distribution system is properly sized and the pressure drops measured across your various equipment are within specifications, any pressure drop noticed at the point of use is indicative of an inadequate volume of air. This could be due to restrictive fittings or undersized air lines, hose, or tube. Check that the point of use product is properly plumbed to compressed air per the manufacturer’s specifications.

EXAIR Products are designed to minimize this pressure drop by restricting the flow of compressed air. The more energy (pressure) that we’re able to bring to the point of use, the more efficient and effective that energy will be. The photo below shows two common examples of inefficient compressed air usage. With an open-ended blow off, a pressure drop occurs upstream inside the supply line. If you were to measure the pressure directly at the point of use, while in operation, you’d find that the pressure is significantly lower than it is at the compressor or further up the line. In the other photo with a modular style hose, some pressure is able to build up but if it gets too high the hose will blow apart. These types of modular style hose are not designed to be used with compressed gases.

EXAIR’s Super Air Nozzles, on the other hand, keep the compressed air right up to the point of discharge and minimize the pressure drop. This, in addition to the air entrainment, allows for a high force while maximizing efficiency. If you’d like to talk about how an EXAIR Intelligent Compressed Air Product could help to minimize pressure drop in your processes, give us a call.

Tyler Daniel, CCASS

Application Engineer

E-mail: TylerDaniel@EXAIR.com

X: @EXAIR_TD

Robert Boyle – Real Men of Genius!

Published on by Jordan T ShouseLeave a comment

EXAIR presents, Real Men of Genius. Today we salute you Mr. Robert Boyle, highly regarded as one of the founders of modern chemistry! Your law perfectly describes the inversely proportional relationship between the absolute pressure and volume of a gas, if the temperature is kept constant within a closed system. (Make sure you go back and read that in the old Budweiser song tune!!)

But back on a serious note, Robert Boyle is a man who changed the way we look at scientific research. From the Scientific Method to the laws that govern gases, Robert Boyle was able to change the very way we look at life and solve our problems. One could say that Robert Boyle didn’t really have what you would call a humble beginning; he was born in January 1627 to the 1st Earl of Cork, Richard Boyle and his wife Catherine Fenton at Lismore Castle in Ireland. When he was only 8 years of age, he was sent off to Eton College in order to study under a private tutor. In 1641, Robert would spend the winter in Florence, Italy studying the “paradoxes of the great star-gazer” Galileo Galilei.

Starting in mid-1644, Robert would build his residence in Dorset, England, where he conducted many experiments and from then devote his life to research. In 1654, Boyle would move to Oxford from Ireland in order to further pursue his studies in chemistry. It was here in 1657 that he would read about Otto von Guericke’s air pump, and would set out to improve the system along with Robert Hooke. In 1659, the “Pneumatic Engine” would be completed, and he began a series of experiments on the properties of air. He would further go on to coin the term factitious airs, which is a term used to describe synthetic gases after isolating what is now understood to be hydrogen.

Boyle’s Law

Though he was primarily interested in chemistry, one of Boyle’s most famous discoveries was what is now known as the first of the gas laws, rightfully named Boyles’s Law.  Boyle’s Law defines the relationship between pressure and volume in a closed area given the mass of an ideal gas. Boyle and his assistant Robert Hooke used a closed J-Shaped tube and poured mercury in from the open side, forcing the air on the other side to contract under the pressure. After repeating this using several different amounts of mercury, Boyle deducted that the pressure of a gas is inversely proportional to the volume occupied by it.

Boyles law apparatus
Boyles law apparatus is used to visualize the relationship between the absolute pressure and volume of a gas.

Robert Boyle passed away on December 31st, 1691, and from his work, EXAIR uses the pressure and volume of compressed air for our Intelligent Compressed Air® Products to make them efficient, safe, and effective.  If you would like to speak more about how EXAIR can benefit your pneumatic system, one of our Application Engineers can help you determine the best solution.

Jordan Shouse
Application Engineer
Email: jordanshouse@exair.com
Twitter: @EXAIR_JS

Robert Boyle image courtesy of Skara Kommun, Creative Commons License

Boyles law apparatus image courtesy of Siyavula Education, Creative Commons License

Compressed Air Efficiency! “Step One”

Published on by Jordan T ShouseLeave a comment

I’m currently in the closing process of selling my first home. This is the house I got married in, brought my first child home to. Needless to say there has been a lot going on to get the place up to selling shape, one of those things was getting the HVAC system checked out to verify its running correctly and efficiently! (Spoiler, mine was running very well thank goodness)

With compressed air being considered a fourth utility its important we check the efficiency of the system and fix issues and install upgrades where we can! EXAIR has six simple steps to optimize your compressed air system. Following these steps will help you to cut electrical costs, reduce overhead, and improve your bottom line. In this blog, I will cover the first step – Measure the air consumption to find sources that use a lot of compressed air.

EXAIR Six Steps To Optimizing Your Compressed Air System

Data is important to have when diagnosing wasteful and problematic areas within your compressed air system. To measure air consumption, flow meters are used to find the volume or mass of compressed air per unit of time. Flow rates are very useful data points to find problems like leaks, over-use in blow-offs, waste calculations, and comparison analysis.

The first step to optimizing compressed air systems within an industrial facility is to get a known baseline. To do so, utilizing a digital flowmeter is an ideal solution that will easily install onto a hard pipe that will give live readouts of the compressed air usage for the line it is installed on.  There is also an additional feature that we offer on the Digital Flowmeters that can help further the understanding of the compressed air demands within a facility.

The Pressure Sensing Digital Flowmeters are available from 2″ Sched. 40 Iron Pipe up to 8″ Sched. 40 Iron Pipe.  As well as 2″ to 4″ Copper pipe.  These will read out and with the additional Data Logger or Wireless Capability options record the information. When coupled with the wireless capability an alarm can be set for pressure drops that give live updates on the system as well as permits data review to see system trends throughout the day.

Generating a pressure and consumption profile of a system can help to pinpoint energy wasters such as timer-based drains that are dumping every hour versus level based drains that only open when needed. A scenario similar to this was the cause of an entire production line shut down nearly every day of the week for a local facility until they installed flowmeters and were able to narrow the demand location down to a filter bag house with a faulty control for the cleaning cycle.

If you would like to discuss the best digital flowmeter for your system and to better understand the benefits of pressure sensing, please contact us.

Jordan Shouse
Application Engineer

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