Air Compressor Motors and Controls, Working Together.

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

EXAIR has a Line Vac for your Application!

With countless number of different Models to fit every application, EXAIR Line Vacs are used to convey everything from the lightest of packing peanuts to heavy steel shot.  They’re versatile, reliable, durable, and incredibly easy to install and operate. 

Line Vacs are EXAIR’s current promotion too, see the offer here.

EXAIR Line Vacs use a small amount of compressed air to generate a powerful vacuum by a Venturi effect.  The unique design of the generator creates a high velocity of air to create a low pressure on one side and a powerful thrust on the other. The Line Vac can pick up and move solid material from light and fluffy batting to dense, heavy and abrasive material and pieces.  They can transfer product horizontally up to 100 feet (30 meters) away and vertically up to 20 feet (6 meters) high.  You can watch a video on the operation of a Line Vac HERE.  Compared to other vacuum or conveying systems, the EXAIR Line Vacs are very quiet, rugged, and powerful. They are exceptionally simple to install and solve many “bucket and ladder”, loading and scrap removal applications. EXAIR makes a variety of Line Vacs in different sizes, styles, and materials to best fit your application.

The standard Line Vac is the most versatile product in this family.  EXAIR stocks a wide range of sizes, materials, and styles for targeting the best solution for moving material.  We have two types of connections, slip-on ends for hose connections and threaded ends for pipe connection.  EXAIR can swap the connections with a slip-on hose on one end with a threaded connection on the other.  They range in diameters from 3/8” (10mm) up to 5” (127mm).  We manufacture the Line Vacs in aluminum, 303SS, and 316SS; but don’t let that deter you if your need them manufactured in any other type of material.  We have high temperature models that can withstand temperatures up to 900 deg. F (482 deg. C).  These Line Vacs work great in applications for loading plastic pellets in hoppers, discarding scrap pieces, trim removal, and transferring material.  If an operator has to carry a container of dry material and climb stairs, a Line Vac could be a much better alternative.

Heavy Duty Line Vac: Hardened Alloy Construction and High Performance

The Heavy Duty Line Vacs are made from a hardened alloy steel for abrasion resistance.  The generators inside these Line Vacs are more powerful than the standard models; so, that they can also convey heavier materials at higher conveyance rates.  They can reach rates as high as 40 lbs./min. (18.2Kg/min) of material.  With the hardened alloy construction, they are great for sand blasting applications, ceramic, glass and steel shot.  They are manufactured with inlet and outlet connections for ship-on hoses or threaded pipes.  EXAIR stocks the Heavy Duty Line Vacs in the range from ¾” (19mm) to 3” (76mm) for both hose and NPT connections.  These Line Vacs are our most powerful design with great wear resistance.

EXAIR’s Light Duty Line Vac

On the other end of the Line-Vac spectrum, EXAIR also manufactures the Light Duty Line Vac.   They use much less compressed air than the other Line Vacs which work great for moving lightweight materials over short distances.  They can also be used for removing smoke and fumes from a work area.  The Light Duty Line Vac ranges from ¾” (19mm) up to 6” (152mm) diameter for slip-on hose connections.  This two-piece design provides an effective way of moving material at a lower cost.  It can be used in applications like hopper loading, fiber tensioning, filling operations, and smoke removal.   For moving material within a short distance, the Light Duty Line Vac could be the proper product to use.

Model 161200-316 – 316 Stainless Steel Sanitary Flange Line Vac

Our latest engineering design within the Line Vac family is the Sanitary Flange Line Vacs.  They can fit within sanitary piping systems to convert pipes into a useful conveyor for bulk material and waste removal.  They use an ISO2852 flange for easy disassembly and cleaning to reduce bacterial entrapment.  They ae made from 316 stainless steel material for superior corrosion resistance.  They come in four different sizes to fit the sanitary flanges from 1-½” up to a 3” flange.  For sensitive applications where cleanliness is a major requirement, the Sanitary Flange Line Vac are manufactured for these conditions.

We are also able to make custom Line Vacs to mean any application, see an example of some unique to the application Line Vacs here, https://blog.exair.com/2020/07/01/custom-products-for-custom-applications/

With all of the EXAIR Line Vacs above, they can be sold as kits.  A kit will include a filter, regulator and a bracket.  (A bracket is not sold with the Light Duty Line Vac kits.)  The filter will help keep the Line Vac clean as well as the product that it is conveying.  The regulator is a great tool to vary the conveyance rates for better control.  The bracket helps to mount the Line Vac to a sturdy base for support.  A useful accessory to conveniently hide the compact Line Vac for ease of use and operation.

If you have any questions on how our Line Vacs can help save you money give us a call! One of our application engineers will be happy to assist!

Jordan Shouse
Application Engineer

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Non Hazardous Purge Cabinet Cooler Systems

Last fall, when our youngest “flew the coop” and moved into a dormitory to begin his college experience, my lovely bride and I also embarked upon an exciting adventure: finding, purchasing, and moving in to our “empty nest” dream house.  While packing up the contents of the house where we had raised a United States Marine AND a hippie college student, I moved my trusty laptop from its perch on a desk in a dark basement corner, where it had resided, in that one spot, for more than a couple years.

As I was looking for its carrying case, I noticed the fan grill was almost completely obscured with more than a couple years’ worth of environmental contamination (or dust).  I vacuumed out the grill, but wondered how much more environmental contamination (dust) had made its way into the deep recesses of the laptop…and more importantly, what might it be doing to the sensitive electronics inside my trusty internet browsing device?

If a computer’s fan in a residential environment can get this dusty, imagine how much worse a control panel on a factory floor can get.

I know I’m not telling you anything you don’t already know, but electronics and dust don’t mix.  We have this conversation a LOT with callers inquiring about our Cabinet Cooler Systems.  The protection they offer against environmental contamination is integral with the protection they offer against heat.  In the panel cooling market, our Cabinet Cooler Systems are unique in that respect: a total protection solution.

When properly installed on a sealed enclosure, the only thing the inside of that enclosure is ever exposed to is cold, clean, moisture free air.  But what if the enclosure can’t be completely sealed?  One option is to use a Continuous Operation Cabinet Cooler System.  It works just as the name implies:  cold air is continuously flowing into the enclosure, creating a constant purge flow…if that cold air is blowing out of any openings in the enclosure, there’s no way for environmental contamination to get in.  Problem solved.

Well…almost.  Something else I’m sure you already know is, compressed air is costly.  Organizations like the Compressed Air & Gas Institute (CAGI) and the Compressed Air Challenge (CAC), who are devoted to optimizing industrial use of compressed air, have lists of “inappropriate uses of compressed air”, and panel cooling is on that list…EXCEPT when they’re thermostatically controlled.  At EXAIR, we couldn’t agree more, and if a caller asks any of us Application Engineers about a Continuous Operation Cabinet Cooler System, they’re inviting us in to a conversation about that.

Sometimes, the initial question is cost…well, we have to pay for the components that make up the Thermostat Controls, so we ask our customers who want those products to as well.   A quick conversation about the operating cost of continuous operation vs thermostat control is usually all that’s required in those cases.

Other times, a panel that can’t be sealed is installed in a particularly dusty or dirty environment, and they want the continuous flow of cold air, as described above, to keep those contaminants out.  A Continuous Operation Cabinet Cooler System will, of course, do that.  But EXAIR wants you to get the most out of your compressed air use, so we developed a “best of both worlds” solution: Non-Hazardous Purge Cabinet Cooler Systems.  Here’s how they work:

  • Based on a few key pieces of data that you can submit in our Cabinet Cooler Systems Sizing Guide, we’ll specify the appropriate Cabinet Cooler System to manage that heat load.
  • The system will be thermostatically controlled: a bimetallic Thermostat, mounted inside the panel, will open and close the Solenoid Valve plumbed in the compressed air supply to operate the Cabinet Cooler as needed to maintain temperature inside the panel.
  • The Solenoid Valve is modified to pass a small amount of air flow (1 SCFM) even when it’s closed.  This saves you from using the full rated air consumption of the Cabinet Cooler when cold air isn’t required, and still maintains enough purge air flow to prevent environmental contaminants from entering a less-than-ideally-sealed enclosure.

Whatever you do, DON’T do THIS to your panel.

The Non-Hazardous Purge option is just one way that EXAIR Corporation can help you address specific environmental challenges that may be presented in electrical and electronic panel cooling applications.  If you’d like to find out more, give me a call.

Russ Bowman, CCASS

Application Engineer
EXAIR Corporation
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Opportunities To Save On Compressed Air

Even casual readers of the EXAIR Blog will notice that we Application Engineers are keen on efficiency.  I just counted sixty-seven blogs on the site that discuss our Six Steps To Optimizing Your Compressed Air System.  Some offer a broad overview, while others focus on specific steps, and one tells us more than I ever expected to learn from an engineering blog about…Bigfoot.

I’m going to take a different tack here – no; I’m not going to write about the Yeti or the Loch Ness Monster, but I may try to get the Jersey Devil into a blog someday.  I will, instead, relate some real-life examples of the success of implementing each individual step.  It’s important to note here that they don’t have to be done in order, or even in total, to achieve impressive results.

  1. Measure the air consumption to find sources that use a lot of compressed air.  Like I just said, you don’t HAVE to do these steps in order, but if you DO intend to pursue a comprehensive solution, this is where you want to start.  The facility manager of a large manufacturing plant did just that when a series of Digital Flowmeters were installed in the branch lines to their production cells.  By comparing their present-day actual usage to the original design specifications, they noticed that usage in a certain cell (due to business growth) had increased to the point that they had raised the main header pressure in an attempt to keep point-of-use pressures at proper levels.  By installing a larger diameter branch line to that cell, they were able to reduce main header pressure from 120psig to 100psig, reducing their compressors’ energy usage (and their share of the electric bill) by 10%.
    Summing Remote Display (left) for remote indication and totalizing data. USB Data Logger takes data from the Digital Flowmeter to your computer and outputs to its own software (shown above) or Microsoft Excel.
  2. Find and fix the leaks in your compressed air system.  A factory once noticed they were losing header pressure overnight, when they were closed.  Using an Ultrasonic Leak Detector, they identified some small leaks that nobody thought were all that significant…until they did the math, comparing previous compressed air consumption (including those leaks) to that of their “new and improved” leak-free system.  Fixing those leaks saved them just over a million cubic feet of compressed air a year.  The exact figure was 1,062,500 cubic feet, annually.  I know this is accurate, because it was us.

  3. Upgrade your blowoff, cooling and drying operations using engineered compressed air products.  This could apply to almost every single order we process, so I’m going use an example from my first day here.  During training, I learned that a customer had recently called to get air consumption data on some EXAIR products they were going to implement as part of an upgrade that was also going to involve purchasing a new compressor.  Their main usage was a number of open-end blow offs that ran continuously.  After outfitting those with Model 1100 Super Air Nozzles and Model 9040 Foot Pedals (so the operators had simple, hands-free control over blowing cycles), they not only found they didn’t need a new air compressor, but were able to shut down an existing 50HP air compressor.
    Foot Pedal + Air Hose + Super Air Nozzle = Instant Blow Off System!
  4. Turn off the compressed air when it isn’t in use.  There are a few methods for doing this, and they’re all pretty easy:
    • Good.  Manual shutoff valves (1/4 turn ball valves are great for this) can be used by mindful operators to shut off compressed air use between production cycles, during lunch breaks, and (I hope this is patently obvious to the most casual observer) at closing time.  I’ve talked to users about doing this, but I don’t have any great success stories about this method.  It relies on someone’s memory in knowing when to operate the valve…and nobody’s remembered to call me back with a full report either.
    • Better.  If you only need air blowing while a machine is running,
      EXAIR stocks Solenoid Valves in a variety of sizes & voltages

      most any qualified industrial electrician can wire a solenoid valve into the on/off control of the machine.  Better yet, if the system has programmable logic control (PLC), it can be used to open & shut that same solenoid valve, to effect blow off only as needed.  I worked with an automotive parts manufacturer who had a robot passing parts between a pair of Model 110042 42″ Aluminum Super Air Knives.  They had taken care to accurately position the Air Knives, and program the robot’s movement & speed, to optimize blow off…but the Air Knives were running continuously.  After a brief conversation with the line foreman, they bought and installed a Model 9065 1 NPT 24VDC Solenoid Valve and “told” the PLC to turn air flow on as the robotic arm approached the Air Knives, and turn it off right after the part had passed through.
    • Best.  In the absence of programmable logic, the simplicity of the EXAIR EFC Electronic Flow Control just can’t be beat.  It’s a standalone system that consists of a Solenoid Valve that’s operated by a photoelectric sensor and controlled by a programmable timer.  Whether it’s a tenth of a second, or a few minutes, waste is waste, and it adds up.  Consider this application writeup from our Optimization Products catalog section:
      Turning air off when it’s not needed adds up, even if it’s just for a few seconds at a time.

       

       

       

  5. Use intermediate storage of compressed air near the point of use.  If
    Prevent intermittent demands from starving other loads with intermediate storage.

    compressed air is used in any sizable amount in your facility, odds are, you have a compressor room.  If it’s done right, this is a good thing for your compressor, but it CAN present some challenges for distribution over large areas.  A user of EXAIR Super Ion Air Knives, for example, installed a Model 9500-60 Receiver Tank in an area some distance from the compressor room to maintain higher air pressure than line loss (from the length of the header pipe) was allowing.  Their other option was to increase their overall header pressure; this allowed them to maintain current costs…increasing system pressure by 2psi equates to a 1% increase in compressed air generation costs.
  6. Control the air pressure at the point of use to minimize air consumption.  In addition to controlling OVERALL compressed air system pressure (see examples 1 & 5 above), using Pressure Regulators to control the supply pressure to specific compressed air operated products will save you money too…the lower the supply pressure, the lower the consumption.  A Model 1101 1/4 MNPT Super Air Nozzle, for example, uses 14 SCFM when supplied at 80psig…that’s where we publish its performance, because that’ll give a good, strong blast of air, suitable for a wide range of typical industrial air blowing applications. A tube manufacturer once replaced two open blow off devices that used about 38 SCFM each with Model 1101’s.  Even though that cut their air consumption by more than half, they were able to cut it even further by regulating the supply pressure to 56psig…that’s the pressure at which they could still get the job done consistently, resulting in ANOTHER 25% reduction in compressed air consumption.

If you’d like to find out more about any, or all, of the Six Steps To Optimizing Your Compressed Air System, give me a call.

Russ Bowman, CCASS

 

 

 

Application Engineer
EXAIR Corporation
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