Tag: air compressor

Compressed Air Use in the Agriculture Industry

Published on by Russ BowmanLeave a comment

The history of agriculture is really the history of civilization. Once our ancestors moved from hunting & gathering to herding & planting, the concepts of villages and trade took off, and here we are, living in the suburbs, exchanging currency for goods at the local supermarket. The methods in which these goods (the food we eat) are processed have evolved from everything being done by hand, to the use of an impressive degree of modern technology. Some of that technology involves compressed air – hence the subject of this blog. Consider:

  • Gasoline or diesel driven air compressors can power tools and pumps in areas where electricity isn’t available.
  • Fertilizers and pesticides are oftentimes sprayed onto crops using products like EXAIR Air Atomizing Spray Nozzles, which generate an even, controllable spray pattern & flow rate, while making extremely small droplet sizes for maximum coverage.
  • Air Operated Conveyors like EXAIR Line Vacs are widely used to move grain, soil, fertilizer, etc., quickly & easily from storage bins or hoppers.
As a coffee lover, there’s not much I enjoy more than specifying a Line Vac for use with coffee, like the one above being used to convey green coffee beans. They’re used for roasted and ground beans too!
  • Blowoff products like EXAIR Super Air Knives are ideal for cleaning and drying produce carried on conveyor belts.
Super Air Knife drying fruits and vegetables

I had the pleasure of assisting a caller with the selection of a wet-dry vacuum for cleanup operations on a dairy farm. Since it was going to be used in an area subject to liquid spills, they wanted a non-electric solution to eliminate shock hazards from dragging an extension cord across a wet floor. They needed a HEPA filter for silica dust, and wanted the ability to quickly change operation from vacuuming up that dust, to cleaning up liquid (like fresh milk) spills.

EXAIR Model 6303 Premium HEPA EasySwitch Wet-Dry Vac System fit the bill perfectly for them. It’s compressed air operated (so no shock hazard), with more than enough vacuum power for wet or dry cleanup, and the ability to easily switch (as advertised) from wet to dry operation. Also, with no moving parts to wear out, it’ll run darn near indefinitely, maintenance free, when supplied with clean compressed air.

For critical dust containment, the HEPA EasySwitch Wet-Dry Vac System is your durable, reliable, compressed air operated solution!

If you would like to read more about the kinds of applications in which our products help customers solve interesting application problems, please visit our Application Database under “Resources” on the website – (registration required, but it’s free & fast). This resource has details of the successful use of EXAIR products across dozens of industries – Agriculture included. In fact, it’s near the top of the list (to be fair, it’s alphabetical). If you’d like to find out more about how EXAIR Intelligent Compressed Air Products can be used to your benefit, give me a call.

Russ Bowman, CCASS

Application Engineer
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Centrifugal Air Compressors

Published on by Jordan T ShouseLeave a comment

There are two main types of compressors, positive displacement and Dynamic.

Positive displacement air compressors raise air pressure by reducing the volume of air within a confined space.  The scroll compressors use two inter-meshing scrolls, where one scroll is moving, and the other scroll is stationary (reference photo below).  Ambient air will get trapped at the inlet side, and as the orbiting scroll moves, the spiral volume gets smaller and smaller.  When volume decreases, the pressure will increase.  Rotary Scroll air compressors are less common in the rotary family, as they are limited in capacity.    

The dynamic type raises the air pressure by using kinetic energy and velocity with rotating impellers that continuously bring in airflow.  In this blog, I will cover the centrifugal type of the dynamic branch. 

As mentioned, the centrifugal compressor works by transforming kinetic energy and velocity into pressure.  Ambient air passes through guide vanes into the center of a rotating Impeller with radial blades and is then pushed outward by a centrifugal force. 

 With the increase in pressure, you will get an increase in heat.  It is a natural occurrence with air compressors.  Heat from the centrifugal compressor is dissipated by heat exchangers before moving onto the next stage.  Multiple stages are required to raise the pressure to a sufficient level for typical industrial plant requirements.  The most common centrifugal air compressors have two to four stages to generate pressures up to 100 to 150 PSIG.  Centrifugal compressors are near the middle of the road regarding efficiency.  Their typical operating cost is 16 to 20 kW/100 CFM. 

Advantages:

  • Up to 1500 HP systems are available
  • Price per horsepower drops as system size increases
  • Supplies lubricant-free air
  • Special installation pads are not required for installation

Disadvantages:

  • Costs more Initially
  • Requires specialized maintenance

No matter the type of air compressor that you use, they are very costly to operate.  To help you use them efficiently and safely, EXAIR offers a range of products that can clean, cool, blow, conserve, and convey.  This would include our Super Air Knives, Super Air Nozzles, Safety Air Guns, Cabinet Coolers, and much more.  If you want to save energy, increase safety, and cut costs no matter what size air compressor you have, contact an Application Engineer at EXAIR.  We will be happy to help you make your use of compressed air as efficient and safe as possible. 

Jordan Shouse
Application Engineer

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Images Courtesy of the Compressed Air Challenge

Air Compressors: Maintenance and Optimization

Published on by John BallLeave a comment

In one of my previous jobs, I was responsible for the operation of the facility, and one of my biggest jobs was the operation of our air compressor.  Like with many industries, the compressor system is the lifeblood of the company.  If the compressor fails, the whole facility will stop.  In this blog, I will share some maintenance items and schedules for air compressors.

Because the cost to make compressed air is expensive, the compressed air system is considered to be a fourth utility.  With such an important investment, you would like to keep it operating as long and efficiently as possible.  To do this, it is recommended to get your air compressor a “checkup” every so often.  I will cover some important items to check.  Depending on the size and type, some items may or may not apply.  But please, always check with the manufacturer of your air compressor.

Intake filter: The intake filter is used to clean the air that is being drawn into the air compressor.  Better filtration results in less debris getting into your system.  Particles can damage the air pump mechanisms over time as well as plug filters and heat exchangers downstream.  If they are not properly monitored and cleaned, the air flow can be restricted.  This will cause the compressor motor to operate harder and hotter.

Compressor Oil: This would be for flooded screws and reciprocating compressors that use oil to lubricate the bearings and sleeves in the air pump.  Most systems have an oil sight to verify levels.  The oil can also be checked for acidity, which will tell the degree at which the oil is breaking down.  Just like the motor oil in your car, you will have to replace it after so many hours of operation.

Belts & couplings: These items transmit the power from the motor to the air pump.  Check their alignment, condition, and tension (belts only) as specified by the manufacturer.  You should have spares on hand in case of any failures.

Electric Motors: A mechanical device that turns electric energy into rotational energy.  It is the main component that uses a lot of energy to make compressed air.  So, some checks are required to foresee any potential issues and major shutdowns.  For the windings inside, the resistance should be measured with a multi-meter, and it should fall within the motor’s specifications.  Another check should be on the start capacitor.  The start capacitor stores energy to give the motor a powerful boost to get it turning.  One other item is the centrifugal switch.  Just like the name states, it will disconnect the start capacitor when the motor starts spinning.  One other item for large electric motors is the phase converter.  These are typically capacitors, and they are designed to keep the direction of three-phase motors going in the correct rotation.  Both types of capacitors can be checked with a multi-meter.

Air/Oil Separators: This filter removes as much oil from the compressed air before it travels downstream.  It returns the oil back to the sump of the air compressor.  If the Air/Oil Separator builds too much pressure drop, excess oil can travel downstream.  Not only will the air pump lose the required oil level, but it will affect the performance of downstream parts like air dryers and after-coolers.  Also, the pressure drop is a waste and can rob your air system of workable energy. 

Internal filters: Many air compressors will come with an attached refrigerated air dryer.   With this type of air compressor, they will place coalescing filters to remove any residual oil.  These filters should be checked for pressure drop.  If the pressure drop gets too high, then it will rob your compressed air system of pressure, and you will not get the required performance.  Some filters come with a pressure drop indicator which can help you to determine the time to change the element.   

Unloader valve: When the air compressor unloads, this valve helps to remove any of the compressed air that is trapped in the cavity.  When the air compressor restarts, it does not have to “work” against this air pressure.  If they do not fully unload, the air compressor will have to work harder to start, wasting energy.

Preventative maintenance is very important.  As for a schedule, I created a rough sequence to check, change, or clean certain items that are important to your air compressor.  You should also check with your local compressor representative for a more detailed maintenance schedule.

Daily:

  • After stopping, remove any condensate from the receiver tank.
  • Check the oil level.

Monthly:

  • Inspect the cooling fins on the air pumps.  Clean if necessary
  • Inspect the oil cooler. Clean if necessary

Quarterly:

  • Inspect the inlet air filter.  Clean or replace if necessary.
  • Check the belt for tension and cracks.  Tighten or replace.
  • Check differential pressure indicators on outlet compressed air filters.
  • Ohm check on the electric motor

Yearly:

  • Replace Air Inlet Filter
  • Replace the air-oil separator
  • Test safety valves and un-loader valve
  • Replace compressed air filters
  • Change oil
  • Grease bearings if required

Keeping your air compressor running optimally is very important for pneumatic operations.  But there is much more than an air compressor in your system.  To help, there are steps that can be used on the demand side.  EXAIR created a Webinar – “Optimizing Your Compressed Air System In 6 Simple Steps”.  With this combination, you can keep a healthy compressed air system.  You can always contact an Application Engineer at EXAIR to see how much money can be saved by energy reduction, safety, and monitoring.  

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

Image courtesy of Compressor1 – Creative commons license

Any Machine Is A Smoke Machine If You Operate It Wrong Enough

Published on by Russ BowmanLeave a comment

While most folks think this old adage applies only to personnel not being familiar with the OPERATION of machinery, it’s also a reminder that ‘operating it right’ necessarily includes keeping up with regularly scheduled preventive maintenance. This includes pretty much anything with moving parts and components in a system that fluids might flow through. But today, I’m going to focus on certain parts of a typical industrial compressed air system. Failing to change oil in an industrial air compressor, for example, will “let the smoke out” just as fast (and sometimes faster) than anything a day-to-day operator can do to it.

The folks at Compressed Air Challenge are dedicated to (and this is right from their website) “helping you enjoy the benefits of improved performance of your compressed air system.” Their “Best Practices For Compressed Air Systems” stresses the importance of:

  • Proper maintenance as a means to ensure operational efficiencies and systems reliability.
  • Continuous checks for preventive maintenance items.
  • Implementing a detailed system maintenance program, including schedules of required maintenance, and records of its performance.

And that’s just from the introduction. It goes on to list the major components that should be included in this program: the compressor, heat exchanger surfaces, lubricant, lubricant filter, air inlet filter, motors, belts, and air/oil separators. The steps for properly maintaining these components range from standard housekeeping practices, to mechanical operations that are typically performed by trained operators, to services that might be best handled by qualified manufacturer’s representatives:

  • Cleaning: The air compressor itself, and any heat transfer surfaces, have to be kept clean & free of contaminants. Moving parts generate heat, and dirt, scale, corrosion, etc. are essentially insulation that’ll prevent that heat from being dissipated.
  • Lubrication: It’s critical to service the lubricant & any lubricant filtration per the manufacturer’s specifications. Again – not doing this is one of the best ways to “let the smoke out” of any machine.
  • Power transmission components: Regular inspection, including alignment checks, of belts & couplings is probably the 2nd best way (next to lubrication maintenance) of keeping the moving parts of the air compressor, and its drive, in good working order.
  • Intake filter: An air compressor will try to compress anything that’s drawn in with its air intake. If it pulls in particulate, that can damage internal surfaces, especially moving parts with tight tolerances to each other, like pistons & cylinders, scrolls & casings, rotary screws & chambers, impellers & volutes, etc., depending on the type of compressor. Plus, anything that makes its way into your compressed air header will also have a chance to foul up your pneumatic tools & devices, and get on anything that you use compressed air to blow off.
  • Motors & drives: Simply put, if you can’t turn the shaft of the compressor, it won’t compress any air. Periodic checks of electric motor windings, bearings, ‘soft start’ capacitors, phase converters, etc., are among the basic maintenance items that operators can inspect.

In addition to the compressor itself, the air distribution system should be properly maintained as well:

  • Filtration: The intake filter is there primarily to protect the compressor. Many times, the aforementioned tight tolerances between the moving parts in the air end will result in (hopefully) small amounts of particulate being carried over into the compressor discharge. There’s usually a main particulate filter, along with a dryer (for entrained moisture – the intake filter won’t do anything about that either), and possibly even a coalescing filter for oil & oil vapor. Good engineering practice calls for servicing those filters when the differential pressure across them reaches a certain value (5psid is a common one), but those elements, being relatively inexpensive, can also be replaced during regularly scheduled downtime as well.
  • Leak detection & repair: Leaks make the compressor run harder, so any reduction in the amount of compressed air leakage will, by definition, reduce the wear & tear on the compressor. EXAIR makes it easy to find them with the Ultrasonic Leak Detector.
  • Filtration Part 2: Don’t forget about contaminants that can enter the system downstream of the compressor, too. Iron pipe headers are subject to internal corrosion, which can result in rust particulate. Environmental pollution can enter if flanges or fittings are broken & made up during maintenance. Point of use filtration, like EXAIR Automatic Drain Filter Separators, can keep this debris (and any moisture that’s not removed by the compressor’s dryer) out of your pneumatic tools & products.
EXAIR has a number of Accessories and Optimization Products to help you get the most out of your compressed air system.

Compressed air is expensive enough without throwing in a bunch of easily preventable repair costs. Schedule time for maintenance, or it’ll schedule the time for you…and it may even send you a ‘smoke signal’ when it’s ready. If you’ve got questions about getting the most out of your compressed air system, we’ve got answers.

Russ Bowman, CCASS

Application Engineer
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