Compressed Air and Pneumatic Systems

Compressed Air Pipe

Compressed air is used to operate pneumatic systems in a facility, and it can be segregated into three main sections; the supply side, the demand side, and the distribution system.  The supply side is the air compressor, after-cooler, dryer, and receiver tank that produce and treat the compressed air.  They are generally found in a compressor room.  The demand side is a collection of devices that will use the compressed air to do “work”.  These pneumatic components are generally scattered throughout the facility.  To connect the supply side to the demand side, a distribution system is required.  Distribution systems are pipes or tubes which carry compressed air from the air compressor to the pneumatic devices.  The three sections have to work together to make an effective and efficient system.

Compressed air is a clean utility that is used in many different ways, and it is much safer than electrical or hydraulic systems.  But most people think that compressed air is free, and it is most certainly not.  Because of the cost, compressed air is considered to be a fourth utility in manufacturing plants.  For an electrical motor to reduce a volume of air by compressing it, it takes roughly 1 horsepower (746 watts) to compress 4 cubic feet (113L) of air every minute to 125 PSI (8.5 bar).  With almost every manufacturing plant in the world utilizing air compressors larger than 1 horsepower, the amount of energy needed is extraordinary.

Let’s determine the energy cost to operate an air compressor by Equation 1:

Equation 1:

Cost = hp * 0.746 * hours * rate / (motor efficiency)

where:

Cost – US$

hp – horsepower of motor

0.746 – conversion KW/hp

hours – running time

rate – cost for electricity, US$/KWh

motor efficiency – average for an electric motor is 95%.

As an example, a manufacturing plant operates a 100 HP air compressor in their facility.  The cycle time for the air compressor is roughly 60%.  To calculate the hours of running time per year, I used 250 days/year at 16 hours/day.  So operating hours equal 250 * 16 * 0.60 = 2,400 hours per year.  The electrical rate for this facility is $0.10/KWh. With these factors, the annual cost to run the air compressor can be calculated by Equation 1:

Cost = 100hp * 0.746 KW/hp * 2,400hr * $0.10/KWh / 0.95 = $18,846 per year in electrical costs.

Filters and Regulator

If we look at the point-of-use or demand side, the compressed air is generally conditioned to be used to run and control the pneumatic system.  The basic units include filters, regulators, and lubricators.  The filters are used to remove any oil, water, vapor, and pipe scale to keep your pneumatic system clean.  They fall into different types and categories depending on the cleanliness level required.

Filter Separators are more of a coarse filtration which will capture liquid water, oil, and particulate.  The Oil Removal Filters are more of a fine filtration which can capture particles down to 0.03 micron.  They are also designed to “coalesce” the small liquid particles into larger droplets for gravity removal.  One other group is for removing oil vapor and smell.  This type of filter uses activated charcoal to adsorb the vapor for food and pharmaceutical industries.  Filters should be placed upstream of regulators.

Pressure Regulators change the pressure downstream for safety and control.  Pneumatic devices need both flow and pressure to work correctly.  The lubricator, which is placed after the Regulator, helps to add clean oil in a compressed air line.  Air tools, cylinders, and valves use the oil to keep seals from wearing with dynamic functions.  Once the compressed air is “ready” for use, then it is ready to do many applications.

For EXAIR, we manufacture products that use the compressed air safely, efficiently, and effectively.  EXAIR likes to use the 5-C’s; Coat, Clean, Cool, Convey and Conserve.  We have products that can do each part with 16 different product lines.  EXAIR has been manufacturing Intelligent Compressed Air Products since 1983.  Compressed air is an expensive system to operate pneumatic systems; but, with EXAIR products, you can save yourself much money.  If you need alternative ways to decrease electrical cost, improve safety, and increase productivity when using compressed air, an Application Engineer at EXAIR will be happy to help you.

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

Benefits of an Ultrasonic Leak Detector

Ultrasonic Leak Detector

As margins get tighter and cost of manufacturing climbs, industries are looking into different areas to be more efficient.  A big focus nowadays is in their compressed air system.  Why is this?  Manufacturers are starting to realize that it takes an abundant amount of electricity to make compressed air.  That is why EXAIR manufactures compressed air products for optimization to get the best efficiency.  But what many manufacturers don’t realize is that quiet little hissing sound from there compressed air lines is costing them much money.   That is why EXAIR has the Ultrasonic Leak Detector.

Finding leaks will save you money

Energy Star, a federal voluntary program ran by the Environmental Protection Agency, offers energy-efficient solutions.  EXAIR has partnered with Energy Star because it underscores our commitment to improve energy savings.  They even wrote an excerpt about compressed air leaks here: Energy Tips: Minimize Compressed Air Leaks.  With compressed air leaks, it can be as much as 30% of your compressed air usage.

When a leak occurs, it emits an ultrasonic noise.  The EXAIR Ultrasonic Leak Detector can pick this up.  It has a frequency range from 20 KHz to 100 KHz, above human hearing, so it can make the inaudible leaks, audible.  With three sensitivity ranges and LED display, you can find very minute leaks.  It comes with headphones and two attachments; the parabola attachment to find leaks up to 20 feet (6 meters) away, and the tube attachment for local proximity to define the exact location of the leak.

In the Energy Tips from Energy Star, they reference estimated leak rates and costs associated with these leaks.  They also recommend a leak prevention program with reference materials to help improve energy savings.  As part of that program, an Ultrasonic Leak Detector is the best way to begin.

Checking pipe fittings

To tell a common success story about the Ultrasonic Leak Detector, an EXAIR customer had a 50-horsepower air compressor.  It started to overwork, overheat, and occasionally shut down.  He thought that he would need to buy a larger air compressor to keep his plant running.  In discussing his problems and requirements, he decided to purchase an Ultrasonic Leak Detector from EXAIR to check for leaks as a possible cause.  He checked every fitting and connection in his facility.  When he finished checking the compressed air system, he found 91 leaks.  (You will be surprised with your system if it is not well maintained).

If we look at a very small 1/16” (1.6mm) diameter hole at 80 PSIG (5.5 bar), it will cost you $360 a year per leak (based on 6000 working hours per year).  Thus, 91 leaks at $360/year will equal $32,760 per year.  After the fittings were reworked with piping compound, the compressor was back operating in a normal range.  There was no need to buy a larger air compressor with capital funds, and he was able to save $32,760 a year by finding and fixing the leaks.

As a little secret with the Ultrasonic Leak Detector, it can do more than find compressed air leaks.  Any issue that creates an ultrasonic noise, the Ultrasonic Leak Detector can find it.  This will include air damper seals, circuit breakers, cracked rubber belts, gas burner leaks, refrigerant leaks, worn bearings, and air brake systems on trucks.  It is a handy tool to find potential issues or problems in other areas other than compressed air systems.

For optimization of your compressed air system, it is very important to find and correct leaks in your piping system.  The Ultrasonic Leak Detector can help you do that.  It is an inexpensive way to solve an expensive problem, compressed air leaks.  If you would like to discuss the features and benefits in more detail, you can contact an Application Engineer at EXAIR.  We will be glad to help you.

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