Tag: compressed air leaks

Starting a Leak Prevention Program

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Since all compressed air systems will have some amount of leakage, it is a good idea to set up a Leak Prevention Program.  Keeping the leakage losses to a minimum will save on compressed air generation costs,and reduce compressor operation time which can extend its life and lower maintenance costs.

SBMart_pipe_800x

There are generally two types of leak prevention programs:

  • Leak Tag type programs
  • Seek-and-Repair type programs

Of the two types, the easiest would be the Seek-and-Repair method.  It involves finding leaks and then repairing them immediately. For the Leak Tag method, a leak is identified, tagged, and then logged for repair at the next opportune time.  Instead of a log system, the tag may be a two part tag.  The leak is tagged and one part of the tag stays with the leak, and the other is removed and brought to the maintenance department. This part of the tag has space for information such as the location, size, and description of the leak.

The best approach will depend on factors such as company size and resources, type of business, and the culture and best practices already in place. It is common to utilize both types where each is most appropriate.

A successful Leak Prevention Program consists of several important components:

  • Baseline compressed air usage – knowing the initial compressed air usage will allow for comparison after the program has been followed for measured improvement.
  • Establishment of initial leak loss – See this blog for more details.
  • Determine the cost of air leaks – One of the most important components of the program. The cost of leaks can be used to track the savings as well as promote the importance of the program. Also a tool to obtain the needed resources to perform the program.
  • Identify the leaks – Leaks can be found using many methods.  Most common is the use of an Ultrasonic Leak Detector, like the EXAIR Model 9061.  See this blog for more details. An inexpensive handheld meter will locate a leak and indicate the size of the leak.

    ULD_Pr
    Using the Model 9061 Ultrasonic Leak Detector to search for leaks in a piping system
  • Document the leaks – Note the location and type, its size, and estimated cost. Leak tags can be used, but a master leak list is best.  Under Seek-and-Repair type, leaks should still be noted in order to track the number and effectiveness of the program.
  • Prioritize and plan the repairs – Typically fix the biggest leaks first, unless operations prevent access to these leaks until a suitable time.
  • Document the repairs – By putting a cost with each leak and keeping track of the total savings, it is possible to provide proof of the program effectiveness and garner additional support for keeping the program going. Also, it is possible to find trends and recurring problems that will need a more permanent solution.
  • Compare and publish results – Comparing the original baseline to the current system results will provide a measure of the effectiveness of the program and the calculate a cost savings. The results are to be shared with management to validate the program and ensure the program will continue.
  • Repeat As Needed – If the results are not satisfactory, perform the process again. Also, new leaks can develop, so a periodic review should be performed to achieve and maintain maximum system efficiency.

In summary – an effective compressed air system leak prevention and repair program is critical in sustaining the efficiency, reliability, and cost effectiveness of an compressed air system.

If you have questions about a Leak Prevention Program or any of the 16 different EXAIR Intelligent Compressed Air® Product lines, feel free to contact EXAIR and myself or any of our Application Engineers can help you determine the best solution.

Brian Bergmann
Application Engineer
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How to Estimate Leaks and the Impact upon a Compressed Air System

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In today’s age where compressed air is often referred to as the 4th utility in an industrial manufacturing facility, leaks throughout the system can add up to serious financial losses. It has been estimated that leaks can waste as much as 20-30 percent of an air compressor output.

waste

Not only are leaks a source of wasted energy, they can also contribute to other losses such as:

  • Causing a drop in system pressure, resulting in air tools to function less efficiently
  • Increasing the air compressor on/off cycles which shortens the life of it and other components in the system
  • Increased maintenance costs and more planned downtime for the maintenance to be performed
  • A need to install of additional compressors to make up for the inefficiencies caused by leaks

For compressors that have start/stop controls – the below formula can be used to estimate the leakage rate in the system-

Leakage Equation 1

To use the above formula, the compressor is started when there is no demand on the system –  all air operated equipment and devices are turned off.  As the air escapes the system through the leaks, the system pressure will drop and the compressor will turn on and cycle to bring the pressure back up to the operating level. Measurement of the average time (T) of compressor run duration, and time (t) of the system pressure to drop to the set-point can be plugged into the formula and a Leakage Percentage established.

Another method to estimate the leakage rate is shown below-

Leakage Equation 2

The above method requires knowledge of the total system volume, which includes downstream air receivers, air mains, and all piping.  To perform the check, bring the system pressure up the normal operating pressure (P1) and then measure the time (T) it takes for the system to drop to pressure (P2) which is generally around half the operating pressure.  The 1.25 is a correction factor to normal system pressure, since the leakage rate will be less as the system pressure is lowered.

A leakage rate greater than 10% typically shows that there are areas of improvement (leaks that can be identified and repaired)

Any leakage testing and estimating should be preformed regularly, at least each quarter, so as to minimize the effect of any new system leaks. The tests are only one part of a leak detection and repair program. The best way to detect leaks is the use of ultrasonic leak detector (shown below.)  To learn more about the EXAIR model 9061 Ultrasonic Leak Detector, check out this blog that was previously published.

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If you have questions about compressed air systems, or would like to talk about any of the EXAIR Intelligent Compressed Air® Products, feel free to contact EXAIR and myself or any of our Application Engineers can help you determine the best solution.

Brian Bergmann
Application Engineer

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Optimizing Your Current Compressed Air System Is Simple

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A few weeks ago, we posted a blog discussing how artificial demand and leaks can lead to poor performance and expensive waste.  Today, I’d like to review how following a few simple steps can help optimize your current compressed air system and reduce compressed air usage.

The first step you want to consider is measuring the air usage in the system. To do this, you want to start at the compressor and check individual leads to each drop point to a blowoff device, record your findings to track the demand. By measuring your compressed air usage, you can locate the source of high usage areas and monitor the usage on each leg of the system. If the demand exceeds the supply, there is potential for problems to arise, such as lowered pressure and force from compressed air operated devices leading to irregular performance.

Digital Flowmeter with wireless capability

EXAIR’s Digital Flowmeters are designed to measure flow continuously and accurately to give you real-time flow measurements of your compressed air system to help identify problems areas.

Step 2 is to locate the source of waste. Again, compressed air leaks can result in a waste of up to 30% of a facility’s compressor output. A compressed air leak detection and repair program can save a facility this wasted air. Implementing such a program can be used as a way for a facility to “find” additional air compressor capacity for new projects. Whenever a leak occurs, it will generate an ultrasonic noise.

Model # 9061 Ultrasonic Leak Detector

Our Ultrasonic Leak Detector is designed to locate the source of ultrasonic sound emissions up to 20’ away. These ultrasonic sound emissions are converted to a range that can be heard by humans. The sound is 32 times lower in frequency than the sound being received, making the inaudible leaks, audible through the included headphones and the LED display gives a visual representation of the leak.

The 3rd step involves finding the source of noisy and wasteful blowoffs, like open pipes or homemade blowoffs, and replacing them with an energy efficient, engineered solution. By replacing these devices, you are not only reducing the amount of waste but also improving operator safety by complying with OSHA safety requirements.

Model # 9104 Digital Sound Level Meter

EXAIR’s Digital Sound Level Meter is an easy to use instrument that measures and monitors the sound level pressure in a wide variety of industrial environments. The source of loud noises can be quickly identified so that corrective measures can be taken to keep sound levels at or below OSHA maximum allowable exposure limits.

The easiest way to reduce compressed air usage and save on operating expense is to turn off the compressed air to a device when it isn’t needed, step 4 in the process. Not only will this save money, in many cases, it can also simplify a process for the operator.

 

Sizes from 1/4″ NPT up to 1-1/4″ NPT are available

A simple manual ball valve and a responsible operator can provide savings at every opportunity to shut down the air flow.

 

120VAC, 240VAC or 24VDC

 

For automated solutions, a solenoid valve can be operated from a machine’s control. For example, if the machine is off, or a conveyor has stopped – close the solenoid valve and save the air.

 

 

Model # 9040 Foot Valve

A foot pedal valve offers a hands free solution to activate an air operated device only when needed, such as being implemented in an operator’s work station.

 

EFC – Electronic Flow Control

For even more control, you can use a device like our EFC or Electronic Flow Control. This helps minimize compressed air usage by incorporating a programmable timing controlled (0.10 seconds to 120 hours) photoelectric sensor to turn off the compressed air supply when there are no parts present. It is suited for NEMA 4 environments and can be easily wired for 100-240VAC.

 

 

Step 5, intermediate storage. Some applications require an intermittent demand for a high volume of compressed air. By installing a receiver tank near the point of high demand, there is an additional supply of compressed air available for a short duration. This will help eliminate fluctuations in pressure and volume.

Model # 9500-60

EXAIR offers a 60 gallon, ASME approved vertical steel tank with mounting feet for easy installation near high demand processes.

Many pneumatic product manufacturers have a certain set of specifications regarding performance at stated input pressures. In many applications, or in the case of using a homemade blowoff device like open pipe, these wouldn’t necessarily require the full rated performance of the device or full line pressure. Controlling the air pressure at the point-of-use device will help to minimize air consumption and waste, step 6.

Pressure Regulators permit easy selection of the operating pressure

By simply installing a pressure regulator on the supply side, you can start off at a low pressure setting and increase the pressure until the desired result is achieved. Not only will this help to conserve energy by only using the amount of air required for the application, it also allows you to fine tune the performance of the point-of-use device to match the application requirements.

If you have any questions, please contact an application engineer at 800-903-9247.

Justin Nicholl
Application Engineer
justinnicholl@exair.com
@EXAIR_JN

 

 

Discharge of Air Through an Orifice

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My Application Engineer colleagues and I frequently use a handy table, called Discharge of Air Through an Orifice. It is a useful tool to estimate the air flow through an orifice, a leak in a compressed air system, or through a drilled pipe (a series of orifices.) Various tables and online calculators are available. As an engineer, I always want to know the ‘science’ behind such tables, so I can best utilize the data in the manner it was intended.

DischargeThroughAnOrifice

The table is frequently found with values for pressures less than 20 PSI gauge pressure, and those values follow the standard adiabatic formula and will not be reviewed here.  The higher air pressures typically found in compressed air operations are of interest to us.

For air pressures above 15 PSI gauge the discharge is calculated using by the approximate formula as proposed by S.A. Moss. The earliest reference to the work of S.A. Moss goes back to a paper from 1906.  The equation for use in this table is-EquationWhere:
Equation Variables

For the numbers published in the table above, the values were set as follows-

                  C = 1.0,      p1 = gauge pressure + 14.7 lbs/sq. in,    and T1 = 530 °R (same as 70 °F)

The equation calculates the weight of air in lbs per second, and if we divide the result by 0.07494 lbs / cu ft (the density of dry air at 70°F and 14.7 lbs / sq. in. absolute atmospheric pressure) and then multiply by 60 seconds, we get the useful rate of Cubic Feet per Minute.

The table is based on 100% coefficient of flow (C = 1.0)  For well rounded orifices, the use of C = 0.97 is recommended, and for very sharp edges, a value of C = 0.61 can be used.

The table is a handy tool, and an example of how we use it would be to compare the compressed air consumption of a customer configured drilled pipe in comparison to that of the EXAIR Super Air Knife.  Please check out the blog written recently covering an example of this process.

If you would like to talk about the discharge of air through an orifice 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 
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Twitter: @EXAIR_BB