Tag: compressed air system

Air Compressor Motors and Controls, Working Together.

Published on by Jordan T ShouseLeave a comment

One of the most important aspect of an efficient compressed air delivery system is effective utilization of compressor controls. The proper use of compressor controls is critical to any efficient compressor system operation. In order to reduce operating costs, compressor controls strategies need to be developed starting with minimizing the discharge pressure. This should be set as low as possible to keep energy costs to a minimum.

The compressor system is designed with maximum air demand in mind. During periods of lower demand compressor controls are used to coordinate a reduction in output that matches the demand. There are six primary types of individual compressor controls:

  1. Start/Stop – This is the most basic control. The start/stop function will turn off the motor in response to a pressure signal.
  2. Load/Unload – The motor will run continuously, but the compressor unloads when a set pressure is reached. The compressor will then reload at a specified minimum pressure setting.
  3. Modulating – Restricts the air coming into the compressor to reduce compressor output to a specified minimum. This is also known as throttling or capacity control.
  4. Dual/Auto Dual – On small reciprocating compressors, this control allows the selection of either Start/Stop or Load/Unload.
  5. Variable Displacement – Gradually reduces the compressor displacement without reducing inlet pressure.
  6. Variable Speed – Controls the compressor capacity by adjusting the speed of the electric motor.

All of these controls then control the compressor motors and they have several different starting methods.

There are several types of modern motor starters:

Full Voltage Starters: The original, and simplest method.  These are similar in theory to the old knife switches, but the operator’s hands aren’t right on the connecting switch.  Full line voltage comes in, and amperage can peak at up to 8 times full load (normal operating) amperage during startup.  This can result in voltage dips…not only in the facility itself, but in the neighborhood.  Remember how the lights always dim in those movies when they throw the switch on the electric chair?  It’s kind of like that.

Reduced Voltage Starters: These are electro-mechanical starters.  Full line voltage is reduced, commonly to 50% initially, and steps up, usually in three increments, back to full.  This keeps the current from jumping so drastically during startup, and reduces the stress on mechanical components…like the motor shaft, bearings, and coupling to the compressor.

Solid State (or “Soft”) Starters: Like the Reduced Voltage types, these reduce the full line voltage coming in as well, but instead of increasing incrementally, they gradually and evenly increase the power to bring the motor to full speed over a set period of time.  They also are beneficial because of the reduced stress on mechanical components.

The Application Engineering team at EXAIR Corporation prides ourselves on our expertise of not only point-of-use compressed air application & products, but a good deal of overall system knowledge as well.  If you have questions about your compressed air system, give us a call.

Jordan Shouse
Application Engineer

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Compressor Photo Credits to Bryan Lee, Creative Commons License

Top Factors for Air Compressor & System Maintenance

Published on by Tyler DanielLeave a comment

Performing regular maintenance on your compressor system helps to keep everything operating in peak condition and ensures you’re not wasting unnecessary energy. Just as you perform regular routine maintenance on your vehicles, a compressed air system also needs a little TLC to keep things running smoothly. Neglected maintenance items can lead to increased energy costs, high operating temperatures, and coolant carryover. Much of these issues can be eliminated simply by performing routine maintenance on the components of the system.

According to the Best Practices for Compressed Air Systems by the Compressed Air Challenge (1), components within the system that need maintained include: the compressor, heat exchanger surfaces, lubricant, lubricant filter, air inlet filter, motors, belts, and air/oil separators.  

The compressor and all surfaces of the heat exchanger need to be kept clean and free of contaminants. When these components are dirty, compressor efficiency is greatly reduced. Any fans and water pumps should also be regularly inspected to ensure that they’re functioning properly. The air inlet filter and piping should also be cleaned. The quality of the air in the facility will impact the frequency, refer to the manufacturer’s specifications for ideal intervals for performing scheduled maintenance.

The lubricant and lubricant filter must also be changed per manufacturer’s specifications. Old coolant can become corrosive, impacting useful life and damaging other components while reducing efficiency. While synthetic lubricants are available that have an extended life compared to standard coolants, this does not extend the life of the lubricant filter itself.

Belts should be routinely checked for tension (every 400 hours is reasonable) to alleviate bearing wear. Belts will stretch and wear under normal operation and must be adjusted periodically. It’s a good practice to keep some spares on hand in the event of a failure.

End use filters, regulators, and lubricators should also be periodically inspected and filter elements replaced as needed. If left unchecked, a clogged filter will increase pressure drop. This can cause both a reduction of pressure at the point of use or an increase in the pressure supplied by the compressor, leading to increased energy costs.

Another often overlooked maintenance item is leak detection and repair. Leaks contribute to unnecessary air usage, pressure drop, and increased energy costs. EXAIR offers an Ultrasonic Leak Detector that can be used to identify the leaks in your system and allow you to make the necessary repairs.

EXAIR Ultrasonic Leak Detector

In order to keep your system running in peak condition, regular maintenance is critical. By paying close attention to the manufacture’s recommendations, and implementing a regular maintenance schedule, you can ensure you’re getting the most out of your system components.

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

(1) Scales, W. (2021). Best Practices for Compressed Air Systems : Second Edition (2nd ed.). The Compressed Air Challenge,.

Compressor system image courtesy of Compressor1 via Flickr Creative Commons License

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

Compressor Image courtesy of Compressor1 via Creative Commons License

Keep Your Pneumatics “Healthy” and “Running Like a Brand New Car”

Published on by John BallLeave a comment

Compressed air systems are used in facilities to operate pneumatic systems, and these systems are vital for industries.  So, it is important to keep them running.  The system can be segregated into three different sections; the supply side, the demand side, and the distribution system.  I like to represent these sections as parts of a car.  The supply side will be the engine; the distribution system will be the transmission; and, the demand side will be the tires.  I will go through each section to help give tips on how to improve the “health” of your pneumatic system.

From the supply side, it will include the air compressor, after-cooler, dryer, and receiver tank that produce and treat the compressed air.  They are generally found in a compressor room somewhere in the corner of the plant.  The air compressor, like the engine of your car, produces the pneumatic power for your plant, and needs to have maintenance to keep it working optimally.  The oil needs to be changed, the filters have to be replaced, and maintenance checks have to be performed.  I wrote a blog that covers most of these items, “Compressed Air System Maintenance”.

To connect the supply side to the demand side, a distribution system is required.  Distribution systems are pipes which carry compressed air from the air compressor to the pneumatic devices.  Just like the transmission on the car, the power is transferred from the air compressor to your pneumatic products.

Maintenance is generally overlooked in this area.  Transmissions have oil which can be detected if it is leaking, but since air is a gas, it is hard to tell if you have leaks.  Energy is lost from your pneumatic “engine” for every leak that you have.  So, it is important to find and fix them.  A study was conducted within manufacturing plants about compressed air leaks.  They found that for plants without a leak detection program, up to 30% of their compressed air is lost due to leaks.  This will be equivalent to running on only 6 cylinders in a V-8 engine.

EXAIR offers the Ultrasonic Leak Detector to find those pesky leaks.  It makes the inaudible “hiss”; audible.  It can detect leaks as far as 20 feet (6m) away with the parabola attachment, and can find the exact location of the leak to be fixed with the tube attachment.

Another area for discussion with the distribution system is contamination like rust, oil, water, and debris.  Compressed air filters should be used to clean the compressed air that supplies your pneumatic products. They can remove the debris for your pneumatic products to have a long life.  You can read about the EXAIR compressed air filters here, “Preventative Maintenance for EXAIR Filters”.

The third section is the demand side.  So, you have an engine that makes the power, the transmission to transfer that power, and the tires to use that power safely and efficiently.  Many managers miss the importance of the demand side within their pneumatic system.  If you are using blow-off devices like open pipes, coolant lines, copper tubes, or drilled pipe; it will be like running your car on flat tires.  It is very unsafe as well as reducing gas mileage.  To improve safety and efficiency, EXAIR has a line of Super Air Nozzles and Super Air Knives.  Not only will it increase your “gas mileage” to save you money, but they also will keep your operators safe.

In this analogy, you can have a high-performance engine and a durable transmission, but if your tires are bald, flat, or cracked; you cannot use your car safely and efficiently.  The same thing with your compressed air system.  You have to optimize your blow-off devices to get the most from your pneumatic system.  EXAIR is a leader in engineered blow-off devices for efficiency and safety.  So, if you want to improve the “health” of your pneumatic system, you should begin at how you are using your compressed air on the demand side.  EXAIR has Application Engineers that will be happy to help you in trying to keep your pneumatic system running like a “brand new car”.

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

 

Photo: Ford Mustang Roadster by openclipart-Vectors.  Pixabay License