Advantages of Thermal Mass or Thermal Dispersion Flow Measurement

EXAIR’s Digital Flow Meter offers an easy way to measure, monitor and record compressed air consumption. The Digital display shows the current amount of compressed air flow, allowing for tracking to identify costly leaks and/or inefficient air users.

dfm

How exactly does the Digital Flow Meter work?  The unit falls under the category of Thermal Mass or Thermal Dispersion type flow meters.  Below shows the backside of a unit.

IMG_7387

Thermal mass flow meters have the advantage of using a simple method of measuring flow without causing a significant pressure drop. The EXAIR units have (2) probes that are inserted through the pipe wall and into the air flow.  Each of the probes has a resistance temperature detector (RTD.) One of the probes measures the temperature of the air flow.  The other probe is heated to maintain a preset temperature difference from the temperature measured by the first probe.  The faster the air flow, the more heat that is required to keep the second probe at the prescribed temperature.  From Heat Transfer principles, the heat energy input required to maintain the preset temperature is based on the mass velocity of the air.  Using basic physical properties for compressed air, the volumetric rate can be determined (SCFM), and displayed.

It is important to note that the compressed air should be filtered to remove oils, and dried to remove water, as these liquids have different physical properties from air, and will cause erroneous readings.

Advantages

  • Easy to install – No cutting or welding required
  • Summing Remote Display and Data Logger available
  • Sensitive at low flows
  • Rugged, reliable and no moving parts
  • No calibration or set-up required
  • Models from 1/2″ to 4″ schedule 40 iron pipe in stock
  • Short lead time for sizes up to 6″ Schedule 40 iron pipe
  • Available for size 3/4″ to 4″ copper pipe
  • New Wireless Capability

If you have any questions about the Digital Flow Meter 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

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Pressure – The Inner Working of the Basic Pressure Gauge

Everyday here at EXAIR we talk about pressure, specifically compressed air pressure. The other day I was looking up our model 9011, 1/4″ NPT Pressure Gauge , and it got me to wondering just how does this small piece of industrial equipment work. The best way to find out is to tear it apart.

9011_exair

Most mechanical gauges utilize a Bourdon-tube. The Bourdon-tube was invented in 1849 by a French watchmaker, Eugéne Bourdon.  The movable end of the Bourdon-tube is connected via a pivot pin/link to the lever.  The lever is an extension of the sector gear, and movement of the lever results in rotation of the sector gear. The sector gear meshes with a spur gear (not visible) on the indicator needle axle which passes through the gauge face and holds the indicator needle.  Lastly, there is a small hair spring in place to put tension on the gear system to eliminate gear lash and hysteresis.

When the pressure inside the Bourdon-tube increases, the Bourdon-tube will straighten. The amount of straightening that occurs is proportional to the pressure inside the tube. As the tube straightens, the movement engages the link, lever and gear system that results in the indicator needle sweeping across the gauge.

Pressure Gauge Top

The video below shows the application of air pressure to the Bourdon-tube and how it straightens, resulting in movement of the link/lever system, and rotation of the sector gear –  resulting in the needle movement.

If you need a pressure gauge 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

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Twitter: @EXAIR_BB

Six Steps To Optimizing Your Compressed Air System – Step 1: Measure

“To measure is to know – if you cannot measure it, you cannot improve it.”
-Lord Kelvin, mathematical physicist, engineer,and pioneer in the field of thermodynamics.

This is true of most anything. If you want to lose weight, you’re going to need a good scale. If you want to improve your time in the 100 yard dash, you’re going to need a good stopwatch. And if you want to decrease compressed air consumption, you’ll need a good flowmeter. In fact, this is the first of six steps that we can use to help you optimize your compressed air system.

Six Steps To Optimizing Your Compressed Air System

There are various methods of measuring fluid flow, but the most popular for compressed air is thermal mass air flow.  This has the distinct advantage of accurate and instantaneous measurement of MASS flow rate…which is important, because measuring VOLUMETRIC flow rate would need to be corrected for pressure in order to determine the true compressed air consumption.  My colleague John Ball explains this in detail in a most excellent blog on Actual (volume) Vs. Standard (mass) Flows.

So, now we know how to measure the mass flow rate.  Now, what do we do with it?  Well, as in the weight loss and sprint time improvements mentioned earlier, you have to know what kind of shape you’re in right now to know how far you are from where you want to be.  Stepping on a scale, timing your run, or measuring your plant’s air flow right now is your “before” data, which represents Step One.  The next Five Steps are how you get to where you want to be (for compressed air optimization, that is – there may be a different amount of steps towards your fitness/athletic goals.)  So, compressed air-wise, EXAIR offers the following solutions for Step One:

Digital Flowmeter with wireless capability.  This is our latest offering, and it doesn’t get any simpler than this.  Imagine having a flowmeter installed in your compressed air system, and having its readings continually supplied to your computer.  You can record, analyze, manipulate, and share the data with ease.

Monitor your compressed air flow wirelessly over a ZigBee mesh network.

Digital Flowmeter with USB Data Logger.  We’ve been offering these, with great success, for almost seven years now.  The Data Logger plugs into the Digital Flowmeter and, depending on how you set it up, records the flow rate from once a second (for about nine hours of data) up to once every 12 hours (for over two years worth.)  Pull it from your Digital Flowmeter whenever you want to download the data to your computer, where you can view & save it in the software we supply, or export it directly into Microsoft Excel.

From the Digital Flowmeter, to your computer, to your screen, the USB Data Logger shows how much air you’re using…and when you’re using it!

Summing Remote Display.  This connects directly to the Digital Flowmeter and can be installed up to 50 feet away.  At the push of a button, you can change the reading from actual current air consumption to usage for the last 24 hours, or total cumulative usage.  It’s powered directly from the Digital Flowmeter, so you don’t even need an electrical outlet nearby.

Monitor compressed air consumption from a convenient location, as well as last 24 hours usage and cumulative usage.

Digital Flowmeter.  As a stand-alone product, it’ll show you actual current air consumption, and the display can also be manipulated to show daily or cumulative usage. It has milliamp & pulse outputs, as well as a Serial Communication option, if you can work with any of those to get your data where you want it.

With any of the above options, or stand-alone, EXAIR’s Digital Flowmeter is your best option for Step One to optimize your compressed air system.

Stay tuned for more information on the other five steps.  If you just can’t wait, though, you can always give me a call.  I can talk about compressed air efficiency all day long, and sometimes, I do!

 

Video Blog: EXAIR Efficiency Lab

The video below is a brief introduction to the EXAIR Efficiency Lab, a free service provided by EXAIR for customers within the USA and Canada.

If you have a single point blowoff that does not have an engineered nozzle, or if you have a wider format blowoff, manifold or home-made drilled pipe, contact an Application Engineer with EXAIR and let us help you to reduce your energy waste. Following are some examples of product where we have helped to save some serious air and reduced noise levels which heightens employee comfort.

Non-engineered blowoffs
Drilled and soldered copper pipe.
Custom manufactured inefficient pipe blowoff

 

The EXAIR Efficiency Lab

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

Pressure Profile: Where to Measure Your Air Pressure

Generic Layout drawing of compressed air piping system.

In order to fully understand how efficient your compressed air system may be, you will need to generate a system pressure profile at some point.   This is a list or diagram of what pressures you have in your compressed air system at specific locations, as well as the pressure required by all the demand devices on your compressed air system.

One of the reasons for the pressure profile is that you may have an application that is far away from the compressor but also highly dependent on a specific operating pressure.   You may also find an application that, due to pressure losses within the system, causes an artificially high pressure demand.

The list below gives the critical points for measuring your compressed air system profile.

  1. At the air compressor discharge. (If using multiple compressors, measure at each.)
  2. If dryers of any type are being used after the compressor measure downstream from the dryer.
  3. Downstream of each filter. (If a particulate filter and oil removal filter are being used it is best to measure downstream of each individual device.   This is to tell when you have more than a 5 psig pressure drop or a clogged filter.)
  4. After each intermediate storage device, such as receiver tanks.
  5. At the point just before the main line from your compressor room branches off to distribution.
  6. The furthest point of each header line you have installed.
  7. On both sides of every filter/regulator units that are at high pressure point of use applications.

To give you an idea of why it is so important to measure these locations, take a look at the blogs we have posted on pressure drop. (Link Here)  As you can tell by the list of blogs that comes up, pressure drop through piping can really cause a lot of wasted energy in your compressed air system.   If you can get a good base line measurement by utilizing a pressure profile then you can start the process to optimizing your compressed air system.

6 steps
The EXAIR Six Steps To Optimizing Your Compressed Air System.

 

If you would like to discuss this or any of the other 6 steps to compressed air optimization, feel free to contact us.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

Back To The Basics (of compressed air)…And The Track

The past several weeks I have been finding myself doing things the more complicated way (I  know how that sounds odd – an engineer that prefers to do things the hard way). Over the weekend I took a brief ride on the motorcycle for a short 15 minute trip that I found to be satisfying, even if it is less direct and a more out-of-the-way route for getting my errands complete.   The route runs past the local university of Mount Saint Joseph, down a winding road that has no houses and only one business, the rest is all woods and a creek.  Finally, this route runs along the mighty Ohio river and back up a steep winding road near my house.

While I have been worrying about all the projects and errands which need to be completed, this more complicated route gives me a moment to decompress and remember that my family at home and few other things are all I need.  Once  I was reminded of that and got some perspective which allowed me to “keep calm and carry on” I proceeded to break my projects and errands down into smaller pieces and everything will start to come together.

I now have a to do list at home as well as a refreshed list at EXAIR of all the items I need to do.   The list at home is considerably more fun as it all involves getting my “new to me” track bike ready for this season.  20140506_134512That’s right, it’s right around the corner, the first track weekend of 2014.  So expect to see some more motorcycle blogs coming and hopefully more ways to use EXAIR products while working on them. It was these newly developed lists that helped me reorganize and get back on track for the new season, sometimes a list is necessary in order to gain perspective, prioritize and begin to take action.

On that note, EXAIR has a list to help you gain perspective, prioritize and take some action toward getting your compressed air system optimized. Our systematic approach using the Six Steps To Compressed Air Optimization has been developed to help you save your compressed air,your hearing, and your money. By following these steps you can lower your compressed air use, minimize workplace noise exposure (OSHA will be happy) and save money on this important utility.

6 steps

 

If you have ever thought of reducing your compressed air costs, use our list to help you gain perspective on this simple process and take some positive steps toward saving your facility some money.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

 

Compressed Air and Halloween Candy

Tomorrow night is Halloween. I live in a suburban subdivision with a high ratio of young families, which makes for a target-rich environment for Trick or Treaters…my boys included. We’ll allow them to enjoy a sensible portion of their haul tomorrow night, and the rest will go into the cabinet over the stove for rationing out over the next week or so.

First to disappear will be the brand name chocolates, candy bars, peanut butter cups, etc. The occasional bags of pretzels/salty snacks will find their way into school lunch bags quickly. Novelty lollipops – the kind with candy or gum in the middle – go fast in my house, but only after the chocolate has been completely exhausted. Individual hard candies linger at the bottom until they’re forgotten about, and eventually get thrown away the next time we need one of those pans we keep in that cabinet…usually when we’re preparing Thanksgiving dinner.

One of the trade publications I read regularly is “Compressed Air Best Practices” Magazine. Every month, there are featured articles that highlight how someone just saved a TON of compressed air by applying various methods and fixes to their systems. Understandably, the opportunities for the largest savings are the most popular…let’s call these the “brand name chocolates.” Common examples of this are:

  • Fixing leaks – I know of a company that saved a million SCF per year this way. (Spoiler alert: it was us.)
  • Replacing open ended blow offs with engineered products. (Spoiler alert again: we’re the undisputed industry leader for this.)

Of course, you can’t manage what you can’t measure. If you’re serious about efficiency, you’ve already got flow meters in place. If not, it’s time for a look at what’s available, and how much of a benefit you’ll get from knowing what your usage is at any given time. Continuing with my candy surplus analogy, these could be considered the novelty lollipops. Departing from the analogy, though, this should be done first (OK; it’s not a perfect analogy). An EXAIR Digital Flowmeter will give you instant, accurate indication of your air usage, and you can make a “before/after” comparison, once those leaks are fixed and your blow offs are upgraded.

Lastly, don’t forget about regular maintenance. Our USB Data Logger is a great addition to the Digital Flowmeter – it allows you to track your usage over time. Those leaks you just fixed weren’t there when the system was new. If you start to see your usage creeping up, you’ll want to find out why. Our Ultrasonic Leak Detector is a great tool for periodic checks. Use it to find any new leaks that pop up, and you’ll stop throwing away compressed air like it was candy.

Russ Bowman
Application Engineer
EXAIR Corporation
(513)671-3322 local
(800)923-9247 toll free
(513)671-3363 fax
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