Tag: compressed air optimization

Manufacturing’s 4th Utility: Compressed Air System Components

Published on by Tyler DanielLeave a comment

In any manufacturing environment, compressed air is critical to the operation of many processes. You will often hear compressed air referred to as a “4th utility” in a manufacturing environment. The makeup of a compressed air system is usually divided into two primary parts: the supply side and the demand side. The supply side consists of components before and including the pressure/flow controller. The demand side then consists of all the components after the pressure/flow controller.

The first primary component in the system is the air compressor itself. There are two main categories of air compressors: positive-displacement and dynamic. In a positive-displacement type, a given quantity of air is trapped in a compression chamber. The volume of which it occupies is mechanically reduced (squished), causing a corresponding rise in pressure. In a dynamic compressor, velocity energy is imparted to continuously flowing air by a means of impellers rotating at a very high speed. The velocity energy is then converted into pressure energy.

Still on the supply side, but installed after the compressor, are aftercoolers, and compressed air dryers. An aftercooler is designed to cool the air down upon exiting from the compressor. During the compression, heat is generated that carries into the air supply. An aftercooler uses a fan to blow ambient air across coils to lower the compressed air temperature.

When air leaves the aftercooler, it is typically saturated since atmospheric air contains moisture. In higher temperatures, the air is capable of holding even more moisture. When this air is then cooled, it can no longer contain all of that moisture and is lost as condensation. The temperature at which the moisture can no longer be held is referred to as the dewpoint. Dryers are installed in the system to remove unwanted moisture from the air supply. Types of dryers available include: refrigerant dryers, desiccant dryers, and membrane dryers.

Also downstream of the compressor are filters used to remove particulate, condensate, and lubricant. Desiccant and deliquescent-type dryers require a pre-filter to protect the drying media from contamination that can quickly render it useless. A refrigerant-type dryer may not require a filter before/after, but any processes or components downstream can be impacted by contaminants in the compressed air system.

Moving on to the demand side, we have the distribution system made up of a network of compressed air piping, receiver tanks when necessary, and point of use filters/regulators. Compressed air piping is commonly available as schedule 40 steel pipe, copper pipe, and aluminum pipe. Some composite plastics are available as well, however PVC should NEVER be used for compressed air as some lubricants present in the air can act as a solvent and degrade the pipe over time.

Receiver tanks are installed in the distribution system to provide a source of compressed air close to the point of use, rather than relying on the output of the compressor. The receiver tank acts as a “battery” for the system, storing compressed air energy to be used in periods of peak demand. This helps to maintain a stable compressed air pressure. It improves the overall performance of the system and helps to prevent pressure drop.

Finally, we move on to the point-of-use. While particulate and oil removal filters may be installed at the compressor output, it is still often required to install secondary filtration immediately at the point-of-use to remove any residual debris, particulate, and oil. Receiver tanks and old piping are both notorious for delivering contaminants downstream, after the initial filters.

Regulator and filter

In any application necessitating the use of compressed air, pressure should be controlled to minimize the air consumption at the point of use. Pressure regulators are available to control the air pressure within the system and throttle the appropriate supply of air to any pneumatic device. While one advantage of a pressure regulator is certainly maintaining consistent pressure to your compressed air devices, using them to minimize your pressure can result in dramatic savings to your costs of compressed air. As pressure and flow are directly related, lowering the pressure supplied results in less compressed air usage.

EXAIR manufactures a wide variety of products utilizing this compressed air to help you with your process problems. If you’d like to discuss your compressed air system, or have an application that necessitates an Intelligent Compressed Air Product, give us a call.

Tyler Daniel, CCASS

Application Engineer
E-mail: TylerDaniel@EXAIR.com
Twitter: @EXAIR_TD

Compressor Image courtesy of Compressor1 via Creative Commons License

Determining Leakage Rate and Cost of Compressed Air Leaks

Published on by Tyler DanielLeave a comment

The electricity costs associated with the generation of compressed air make it the most expensive utility within an industrial environment. In a   poorly maintained compressor system, up to 30% of the total operational costs can be attributed simply to compressed air leaks. While this wasted energy is much like throwing money into the air, it can also cause your compressed air system to lose pressure. This can reduce the ability of the end use products to function properly, negatively impacting production rates and overall quality. Luckily, it’s quite easy to estimate the leakage rate and is something that you should be including in your regular PM schedule.

According to the Compressed Air Challenge, a well-maintained system should have a leakage rate of less than 5-10% of the average system demand. To estimate what your leakage rate is across the facility, first start by shutting off all of the point of use compressed air products so that there’s no demand on the system. Then, start the compressor and record the average time it takes for the compressor to cycle on/off. The compressor will load and unload as the air leaks cause a pressure drop from air escaping. The percentage of total leakage can be calculated using the following formula:

Leakage % = [(T x 100) / (T + t)]

Where:

T = loaded time (seconds)

T = unloaded time (seconds)

The leakage rate will be given in a percentage of total compressor capacity lost. This value should be less than 10% for a well-maintained system. It is not uncommon within a poorly maintained system to experience losses as high as 20-40% of the total capacity and power.

A leak that is equivalent to the size of a 1/16” diameter hole will consume roughly 3.8 SCFM at a line pressure of 80 PSIG. If you don’t know your company’s air cost, a reasonable average is $0.25 per 1,000 SCF. Let’s calculate what the cost would be for a plant operating 24hrs a day, 7 days a week.

3.8 SCFM x 60 minutes x $0.25/1,000 SCFM =

$0.06/hour

$0.06 x 24 hours =

$1.44/ day

$1.44 x 7 days x 52 weeks =

$524.16 per year

A small leak of just 3.8 SCFM would end up costing $524.16. This is just ONE small leak! Odds are there’s several throughout the facility, quickly escalating your operating costs. If you can hear a leak, it’s a pretty severe one. Most leaks aren’t detectable by the human ear and require a special instrument to convert the ultrasonic sound created into something that we can pick up. For that, EXAIR has our Model 9061 Ultrasonic Leak Detector.

ULD_Pr
Model 9061 ULD w/ parabola attachment checking for compressed air leaks

Implementing a regular procedure to determine your leakage rate in the facility as well as a compressed air audit to locate, tag, and fix any known leaks should be a priority. The savings that you can experience can be quite dramatic, especially if it’s not something that has ever been done before!

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

Save Your Compressed Air Today with These Simple Methods

Published on by Russ BowmanLeave a comment

When discussing ROI, return on investment, for an industrial compressed air system it is necessary to  understand what it costs to produce compressed air.  Generally we calculate that it costs .25 cents to produce 1,000 SCF (Standard Cubic Feet) of compressed air here in the Midwest of the United States. For our example let’s consider a typical 250 HP industrial compressor running 24 hours per day/5 days per week for 52 weeks.  This compressor can generate 374,400,000 SCF per year, using the industry standard utility cost for the Midwest of .25 cents per 1,000 SCF it will cost $93,600 to produce that volume of compressed air.

To avoid wasting money on compressed air generation it is extremely important to eliminate unintended or wasteful compressed air use in your plant. The two main offenders are leaks and open tube blow-offs.  While soapy water is a good method for discovering leaks, EXAIR offers the Ultrasonic Leak Detector.  This handy device allows leaks to be detected at distances of up to 20′ away! Also consider how safe and convenient it is to find leaks in overhead pipes while standing on the ground instead of on a ladder. Using a tool like this to do an entire system leak audit can easily result in many small leaks being identified and when fixed result in a large savings.

open tubes
Thirteen Open Tube Blow-Offs

Now let’s look at what an open pipe or tube may consume. A single 1/4″ OD copper tube can use 33 SCFM @ 80 PSIG inlet pressure.  Using the manifold pictured above as our example with 13 open tubes, each tube can consume 33 SCFM @ 80 PSI inlet pressure. With 13 open tubes running 24 hours a day, 5 days a week, 52 weeks per year equates to a total consumption of  160,617,600 SCF annually.  If we installed the EXAIR model 1100 Super Air Nozzle  using a simple compression fitting we would reduce the air consumption dramatically.  The EXAIR 1100 Super Air Nozzle consumes 14 SCFM @ 80 PSIG inlet pressure, running 24 hours a day, 5 days a week, 52 weeks per year equates to a total consumption of 68,140,800 SCF annually.  That change will save you 92,476,800 SCF annually which is equal to $23,119.20 and 24.7% of air compressor capacity!  These calculations are all based on continuous running applications, if intermittent operation is possible consider the EXAIR Electronic Flow Control for even greater savings.  The EXAIR Electronic Flow Control combines a photoelectric sensor with timing control that limits compressed air use by turning it off when no part is present

Open pipe blow offs also violate OSHA standard 29 CFR 1910.242(b) requirement for using compressed air for cleaning when pressurized above 30 PSIG. Not to mention they generally are louder than 90 dBA, which is the maximum allowable noise exposure without hearing protection under OSHA standard 29 CFR – 1910.95 (a). The EXAIR engineered Super Air Nozzle is a great way to avoid a OSHA fine.

A great product that will help you keep your fingers on the pulse of compressed air consumption and demand is by incorporating the EXAIR Digital Flow Meter.  This handy item mounts directly to the pipe.  The digital display shows the amount of compressed air being used in any leg of your distribution system.  The Digital Flow Meter is offered in sizes for 1/2″ – 4″ Schedule 40 Iron Pipe and 3/4″ – 4″ Copper Pipe.  It also is available with the Summing Remote Display that is prewired with a 50′ cable, it is powered by the Digital Flow Meter and with a push of the button will display either the current compressed air consumption, consumption for the previous 24 hours or the total cumulative usage.

The Digital Flowmeters are also available with wireless capability using the ZigBee mesh network protocol, data can be passed from meter to meter to extend the distance over which the wireless system can operate.  Each meter has a range of up to 100′ (30 meters). Or you can opt for the USB Data Logger option.  The USB Data Logger can store approximately 9 hours of readings if set to sample once every second or up to 2 years if sampled every 12 hours.

If you would like to talk about any of the quiet EXAIR Intelligent Compressed Air® products or our line of Optimization Products, feel free to contact me or any EXAIR  Application Engineer.

Russ Bowman, CCASS

Application Engineer
EXAIR Corporation
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Six Steps to Compressed Air Optimization: Step 2 – Find and Fix Leaks.

Published on by johnball2014Leave 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.  The compressed air system is considered to be the “forth” utility behind gas, water, and electricity.  It is necessary for pneumatic systems, but it is the least efficient of the utilities.  For every $1.00 that is put into making compressed air, you only get roughly 5¢ of work from it.  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 second step – find and fix leaks.

One of the largest problems affecting compressed air systems is leaks.  That quiet little hissing sound from the pipe lines is costing your company much money.  A study was conducted by a university to determine the percentage of air leaks in a typical manufacturing plant.  In a poorly maintained system, they found on average that 30% of the compressor capacity is lost through air leaks.  For a 100 hp compressor, you are losing 30 hp into the ambient air.  To put a dollar value on it, a leak that you cannot physically hear can cost you as much as $130/year.  That is just for one inaudible leak in hundreds of feet of compressed air lines.  For the leaks that you can hear, you can tell by the chart below (**Note 1) the amount of money that can be wasted by the size of the hole.  Unlike a hydraulic system, compressed air is clean; so, leaks will not appear at the source.  You have to locate them by some other means.

Most leaks occur where you have threaded fittings, connections, hoses, and pneumatic components like valves, regulators, and drains.  The Optimization product line from EXAIR are designed to help improve your compressed air system, and the most effective way is to eliminate leaks.  The Ultrasonic Leak Detectors can find the air leaks, and the Digital Flowmeters can monitor your system for air leaks.  With both of these products included in your leak preventative program, you will be able to keep your compressed air system running optimally and reduce the “hidden” cost of leaks.

Ultrasonic Leak Detector

EXAIR Ultrasonic Leak Detector:

When a leak occurs, it emits an ultrasonic noise caused by turbulence from the gas escaping.  This ultrasonic noise can be at a frequency above the audible level for human hearing.  The EXAIR Ultrasonic Leak Detector can pick up these frequencies and make the leaks audible.  With three sensitivity ranges and LED display, you can find very minute leaks.  It comes with two attachments; the parabola to locate leaks up to 20 feet away, and the tube attachment to define the exact location in the pipe line.  Once you find a leak, it can be marked for fixing.

EXAIR’s Digital Flowmeter w/ USB Data Logger

EXAIR Digital Flowmeter:

With the Digital Flowmeters, you can continuously monitor for waste.  Air leaks can occur at any time within any section of your pneumatic area.  You can do systematic checks by isolating sections with the Digital Flowmeter and watch for a flow reading.  Another way to monitor your system would be to compare the results over time.  With the Digital Flowmeters, we have a couple of options for recording the air flow data.  We have the USB Datalogger for setting certain time increments to record the air flows.  Once the information is recorded, you can connect the USB to your computer, and with the downloadable software, you can view the information and export it into an Excel spread sheet.  We also offer a wireless capability option with the Digital Flowmeters.  You can have multiple flow meters that can communicate with your computer to continuously log and record the flow information.  Once the flow information starts trending upward for the same process, then you can use the Ultrasonic Leak Detector to find the leak.  It can also give you a preventative measure if a pneumatic system is starting to fail.

Compressed air leaks will rob you in performance, compressor life, and electrical cost.  It is important to have a leak preventative program to check for leaks periodically as they can happen at any time.  The EXAIR Ultrasonic Leak Detector and the Digital Flowmeters will help you accomplish this and optimize your compressed air system.  Once you find and fix all your leaks, you can then focus on improving the efficiency of your blow-off devices with EXAIR products and save yourself even more money.

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

 

**Note 1: Chart was published by Compressed Air Challenge in April 1998 – Rev. 0