Tag: compressed air flow

Six Steps to Optimizing:  Step 1 – Measure the Air Consumption

Published on by John BallLeave a comment

Since air compressors use a lot of electricity to make compressed air, it is important to use the compressed air as efficiently as possible. 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 – Measuring the air consumption to find sources that use a lot of compressed air.

Six Steps to Optimizing Your Compressed Air System

Information is important to diagnose 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.

There are many different types of flow meters. Many of them entail a breakdown of your current compressed air lines by cutting, welding, or dismantling for installation. This will add costs in downtime and maintenance staff. But, not with the EXAIR Digital Flowmeters. In this blog, I will share the features and benefits of the Digital Flowmeters, including options for you to start measuring and optimizing your compressed air system in Step 1.

Overall, it only takes a few minutes to install and start measuring. The installation kit comes with a drill guide to properly locate the two holes in the pipe. The Digital Flowmeter uses a clamp to mount onto the pipe and to seal the area around the probes. Once it is powered, the unit is ready to measure the air flow inside the pipe with a large LED display. The display can be customized to show flow readings in three different units; SCFM, M3/hr or M3/min; and, it can display the Daily Usage and Cumulative Usage. 

To get started, the EXAIR Digital Flowmeter is a thermal dispersion device that can accurately measure compressed air flows. They use two sensing probes for comparative analysis. One probe is a temperature sensing probe, and the other is a flow-sensing probe. By comparing these, the Digital Flowmeter can measure precisely the mass of air flow without needing to be re calibrated. They are a cost-effective, accurate, and simple way to measure compressed air flow.

EXAIR stocks a large volume of Digital Flowmeters to ship on the same day for U.S. and Canadian customers. We also offer a 30-day unconditional guarantee to try them out. We stock meters for pipe diameters from ½” NPT to 4″ NPT Schedule 40 black pipe. EXAIR can also offer flow meters up to 8″ NPT black pipe; copper pipes with diameters from 3/4″ to 4″, and aluminum pipes with diameters ranging from 40mm to 101mm. If you have another type of piping for your compressed air system, you can give us the material, O.D. or I.D., and wall thickness. We may still be able to get a Digital Flowmeter for you.

For measuring, all the units come standard with a 4 – 20mA analog output. Per your request, we can change this signal to a serial output for RS-485 or Ethernet connections. What more can we offer with the EXAIR Digital Flowmeter? Options. Options upgrade the flow meters to better suit your application. Here is a list below:

EXAIR’s Digital Flowmeter w/ USB Data Logger

USB Data Logger: This option allows for a recording of the flow information. With a software download, you can set up the USB Data Logger to record the flow from once a second (roughly 9 hours of storage) to every 12 hours. After the data points are recorded, you can then download the information into the software to review. Then the information can be uploaded to an Excel program to do further analysis.

Summing Remote: With compressed air pipes running along the ceiling and walls, reading the Digital Flowmeter may be difficult. The Summing Remote has a 50-foot (15 meter) cable to bring the LED display into viewing. The Summing Remote is powered by the Digital Flowmeter, and it can be positioned at eye level, inside managers’ rooms, or around large equipment for monitoring.

Hot Tap Digital Flowmeter: This option is a great way to install a Digital Flowmeter on the pipe without shutting down the compressed air line. We offer this option for 2″ and larger for steel and copper pipes. It gives a quick and easy way to attach them if you have a 24-hour operation or a critical process that needs to run continuously.

Pressure Sensing Digital Flowmeter: If you would like to know the compressed air flow and the air pressure, this option will be able to do this. They are available with the Digital Flowmeters for steel and copper pipes that are 2″ and larger, and for the aluminum piping that is 50mm and larger. This option can display pressure units in either PSI or Bar right on the same LED display that shows the flow readings.

Block-Off Rings: If you want to move your Digital Flowmeter, the Block-Off Rings will be able to cover the openings in your compressed air pipe. They seal around the drilled opening when the Digital Flowmeter is removed from the pipe. They are reusable; so, they can be removed if you want to remount the Digital Flowmeter in the same spot. If you want to use one flow meter in different locations, the Block-Off Rings allow you to do this.

When you need to analyze your pneumatic components, flow is an important point in diagnosing the overall “health” of your compressed air system. The EXAIR Digital Flowmeter can give you that important data point. With optimization, you can cut your energy consumption, improve efficiency, and save yourself money. This blog is an overview of Step 1 of six steps. You may have more questions about the other steps, and that is great! You can find them in other EXAIR blogs, or you can contact an Application Engineer at EXAIR.

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

Webinar Replay: SCFM, ACFM, ICFM, CFM – Why So Many Terms For Air Flows?

Published on by Tyler DanielLeave a comment

EXAIR’s latest addition to the Fall Webinar series was a discussion on the topic of volumetric air flow terms: SCFM, ACFM, ICFM, and CFM. In the compressed air world, these terms are used often to quantify the performance of a compressor or the point-of-use equipment on the supply side of your system. Since conditions will vary from one site location to another, it’s important that we understand how certain variables can change the performance of your system. The webinar is available to view on demand on the EXAIR.com.

The term SCFM (Standard Cubic Feet Per Minute) is used to allow us to make an apples to apples comparison across different equipment. The performance is rate at a set of “standard” conditions to remove any potential variables from the equation. CAGI, or the Compressed Air and Gas Institute, uses the standard conditions of: 14.5 psia, 0% relative humidity (RH), and 68°F. This allows us to compare different devices without needing to make any sort of adjustments.

Variables such as elevation (barometric pressure), relative humidity, and temperature all change the performance and must be considered.

With elevation, we’re looking at the atmospheric or barometric pressure at the location of operation. One way to illustrate this to consider a balloon. If you inflated a balloon at sea-level, or 14.5 psia, then carry that same balloon up to the top of Mt. Everest what would happen? Using Boyle’s Law (P1 x V1 = P2 x V2), we’re able to calculate the exact volume of the balloon. At the peak of Mt. Everest, pressure is significantly lower at roughly 4.5 psi. The balloon when taken to the peak at 4.5 psi would become 3.2x it’s original size as the pressure acting on the outside of the balloon decreases.

Relative humidity tells us how much moisture content is contained within a specific volume of air. Water molecules cannot be compressed, so when the air is compressed this water takes up the same volume. The water condenses in the inter-coolers and after-coolers or is removed via drains and dryers downstream. So, 1 cubic foot of air coming into the compressor weigh more than 1 cubic foot of air out due to this water vapor loss.

As temperature increases, so does air pressure as the molecules in the air speed up and come into contact with one another and the walls of its container at a more rapid pace. Air can also hold a greater volume of moisture at higher temperatures. So, the balance between RH and temperature is an important consideration when determining actual performance, or ACFM.

In the webinar, we walked through two different examples to highlight the changes in these variables and how it impacts the performance of a compressed air system. If you were unable to attend live, the webinar is available to view on demand on the EXAIR website. We have this latest webinar posted there on the website along with all prior webinars as well! There, we talk about topics ranging from compressed air system optimization, static electricity, OSHA Compliance, and more! Check out the available webinars on the Resources tab of the EXAIR.com page today for all the knowledge you’ll need about your compressed air system and processes.

Tyler Daniel, CCASS

Application Engineer

E-mail: TylerDaniel@EXAIR.com

Twitter: @EXAIR_TD

ICFM, SCFM, ACFM, CFM What does it all mean!

Published on by Jordan T ShouseLeave a comment

A common question we get asked is “What does SCFM mean?” Most people are aware of CFM but the “S” in front seems to be less known about! Well strap on your seat belt, we are about to go into a compressed air worm hole all about volumetric flow rates!

Here at EXAIR we rate all of our products air consumption in SCFM at a given supply pressure. CFM stands for Cubic Feet per Minute, but one definition will not satisfy the conditions that will be experienced in many applications by a number of variables  (altitude, temperature, pressure, etc.). Air by nature is a compressible fluid. The properties of this fluid are constantly changing due to the ambient conditions of the surrounding environment.

This makes it difficult to describe the volumetric flow rate of the compressed air. Imagine you have a cubic foot of air, at standard conditions (14.696 psia, 60°F, 0% Relative Humidity), right in front of you. Then, you take that same cubic foot, pressurize it to 100 psig and place it inside of a pipe. You still have one cubic foot, but it is taking up significantly less volume. You have probably heard the terms SCFM, ACFM, and ICFM when used to define the total capacity of a compressor system. Understanding these terms, and using them correctly, will allow you to properly size your system and understand your total compressed air consumption.

SCFM is used as a reference to the standard conditions for flow rate. This term is used to create an “apples to apples” comparison when discussing compressed air volume as the conditions will change. EXAIR publishes the consumption of all products in SCFM for this reason. You will always notice that an inlet pressure is specified as well. This allows us to say that, at standard conditions and at a given inlet pressure, the product will consume a given amount of compressed air. It would be nearly impossible, not to mention impractical, to publish the ACFM of any product due to the wide range of environmental conditions possible.

ACFM stands for Actual Cubic Feet per Minute. If the conditions in the environment are “standard”, then the ACFM and SCFM will be the same. In most cases, however, that is not the case. The formula for converting SCFM to ACFM is as follows:

ACFM = SCFM [Pstd / (Pact – Psat Φ)](Tact / Tstd)

Where:

ACFM = Actual Cubic Feet per Minute
SCFM = Standard Cubic Feet per Minute
Pstd = standard absolute air pressure (psia)
Pact = absolute pressure at the actual level (psia)
Psat = saturation pressure at the actual temperature (psi)
Φ = Actual relative humidity
Tact = Actual ambient air temperature (oR)
Tstd = Standard temperature (oR)

The last term that you’ll see floating around to describe compressed air flow is ICFM (Inlet Cubic Feet per Minute). This term describes the conditions at the inlet of the compressor, in front of the filter, dryer, blower, etc. Because several definitions for Standard Air exist, some compressor manufacturers have adopted this simpler unit of measure when sizing a compressor system. This volume is used to determine the impeller design, nozzle diameter, and casing size for the most efficient compressor system to be used. Because the ICFM is measured before the air has passed through the filter and other components, you must account for a pressure drop.

The inlet pressure is determined by taking the barometric pressure and subtracting a reasonable loss for the inlet air filter and piping. According to the Compressed Air Handbook by the Compressed Air and Gas Institute, a typical value for filter and piping loss is 0.3 psig. The need to determine inlet pressure becomes especially critical when considering applications in high-altitudes. A change in altitude of more than a few hundred feet can greatly reduce the overall capacity of the compressor. Because of this pressure loss, it is important to assess the consumption of your compressor system in ACFM. To convert ICFM to ACFM use the following formula:

ICFM = ACFM (Pact / Pf) (Tf / Tact)

Where:

ICFM = Inlet Cubic Feet Per Minute

Pf  = Pressure after filter or inlet equipment (psia)

Tf = Temperature after filter or inlet equipment (°R)

If you’re looking into a new project utilizing EXAIR equipment and need help determining how much compressed air you’ll need, give us a call. An Application Engineer will be able to assess the application, determine the overall consumption, and help recommend a suitably sized air compressor.

Jordan Shouse
Application Engineer

Send me an email
Find us on the Web 
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Twitter: @EXAIR_JS

Laminar vs. Turbulent Flow

Published on by Jordan T ShouseLeave a comment

Laminar flow is an fundamental component of compressed air efficiency. Believe it or not, laminar flow is controlled exclusively by the airline used in a compressed air system. To fully understand the effects of laminar flow in a compressed air system, we need to explain exactly what it is.

Fluids & gases are unique in their ability to travel. Unlike solid molecules that remain stationary whose molecules tend to join others of the same kind; fluid molecules aren’t so picky. Fluid molecules, such as gases and liquids, partner with different molecules and are difficult to stop.

Laminar flow describes the ease with which these fluids travel; good laminar flow describes fluid travelling as straight as possible. On the contrary, when fluid is not travelling straight, the result is turbulent flow.

PVDF Super Air Knife
Laminar Flow

Turbulent air flow results in an inefficient compressed air system. This may not seem like a major concern; yet, it has huge impacts on compressor efficiency. Fluid molecules bounce and circle within their path, causing huge energy wastage. In compressed air systems, this turbulent airflow results in a pressure drop. How do you avoid this from happening? It all comes down to compressed air system design.

Flow type
Laminar vs. Turbulent Flow

The design and material of the air pipe, as well as the positioning of elbows and joints, has a direct connection to laminar flow and pressure drop. To avoid high energy consumption of your compressed air system, reducing pressure drop is key.

If your system is experiencing high pressure drop, your compressor has to work overtime to provide the needed air pressure. When your compressor works overtime, it not only increases your maintenance costs, but also your energy bills.

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
Send me an email
Find us on the Web 
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 Twitter: @EXAIR_JS