How to Size a Receiver Tank and Improve your Compressed Air System

Receiver Tank: Model 9500-60

My colleague, Lee Evans, wrote a blog about calculating the size of primary receiver tanks within a compressed air system.  (You can read it here: Receiver Tank Principle and Calculations).  I would like to expand a bit more about secondary receiver tanks.  They can be strategically placed throughout the plant to improve your compressed air system.  The primary receiver tanks help to protect the supply side when demands are high, and the secondary receiver tanks help systems on the demand side to optimize performance.

Circuit Board

I like to compare the pneumatic system to an electrical system.  The receiver tanks are like capacitors.  They store energy produced by an air compressor like a capacitor stores energy from an electrical source.  If you have ever seen an electrical circuit board, you notice many capacitors with different sizes throughout the circuit board (reference photo above).  The reason is to have a ready source of energy to increase efficiency and speed for the ebbs and flows of electrical signals.  The same can be said for the secondary receiver tanks in a pneumatic system.

To tie this to a compressed air system, if you have an area that requires a high volume of compressed air intermittently, a secondary receiver tank would benefit this system.  There are valves, cylinders, actuators, and pneumatic controls which turn on and off.  And in most situations, very quickly.  To maximize speed and efficiency, it is important to have a ready source of air nearby to supply the necessary amount quickly.

For calculating a minimum volume size for your secondary receiver tank, we can use Equation 1 below.  It is the same as sizing a primary receiver tank, but the scalars are slightly different.  The secondary receivers are located to run a certain machine or area.  The supply line to this tank will typically come from a header pipe that supplies the entire facility.  Generally, it is smaller in diameter; so, we have to look at the air supply that it can feed into the tank.  For example, a 1” NPT Schedule 40 Pipe at 100 PSIG can supply a maximum of 150 SCFM of air flow.  This value is used for Cap below.  C is the largest air demand for the machine or targeted area that will be using the tank.  If the C value is less than the Cap value, then a secondary tank is not needed.  If the Cap is below the C value, then we can calculate the smallest volume that would be needed.  The other value is the minimum tank pressure.  In most cases, a regulator is used to set the air pressure for the machine or area.  If the specification is 80 PSIG, then you would use this value as P2.  P1 is the header pressure that will be coming into the secondary tank.  With this collection of information, you can use Equation 1 to calculate the minimum tank volume.  So, any larger volume would fit the requirement as a secondary receiver tank.

Secondary Receiver tank capacity formula (Equation 1)

V = T * (C – Cap) * (Pa) / (P1-P2)

Where:

V – Volume of receiver tank (cubic feet)

T – Time interval (minutes)

C – Air demand for system (cubic feet per minute)

Cap – Supply value of inlet pipe (cubic feet per minute)

Pa – Absolute atmospheric pressure (PSIA)

P1 – Header Pressure (PSIG)

P2 – Regulated Pressure (PSIG)

If you find that your pneumatic devices are lacking in performance because the air pressure seems to drop during operation, you may need to add a secondary receiver to that system.  For any intermittent design, the tank can store that energy like a capacitor to optimize the performance.  EXAIR stocks 60 Gallon tanks, model 9500-60 to add to those specific locations, If you have any questions about using a receiver tank in your application, primary or secondary, you can contact an EXAIR Application Engineer.  We can restore that efficiency and speed back into your application.

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

 

Photo: Circuit Board courtesy from T_Tide under Pixabay License

No Matter The Size of The System, Air Leaks Should be Fixed

Just last night I was in my garage tinkering around with a vintage Coleman Camping lantern from 1949 that I am working on refurbishing. I grabbed my parts washing bin (A bread pan my wife let me have because she didn’t like the way it cooked bread) and was reminded that I had been soaking a helmet lock from a friends dirt bike in a penetrating oil. I removed the lock from the pan, wiped it down, then went to my trusty 30 gallon compressor to use a Safety Air Gun to blow the residual oil out of the lock.

When not in use my compressor stays turned off and I modified the factory outlet to include a quarter turn ball valve so that I can retain all air in the receiver tank and not have to charge the tank up every time that I use it. As I turned the valve on I was reminded that I have a rather large air leak that can drain the 30 gallon tank down from 150 psig to 60 psig within a few hours.

While my air system is almost as simple as it can be, single air hose real with an additional quick disconnect before the hose reel for small quick blow offs, it still has over a dozen connections within the system. While my worst offending leak is audible to my slightly aged ears there are other leaks that I cannot see or hear. That is unless I use one of two methods I know to find leaks.

The easiest is right out of our 6 Steps of Compressed Air Optimization, the Ultrasonic Leak Detector (ULD). The ULD is a versatile, low cost, hands free electronic device that will quickly and easily detect the general vicinity of a leak and then easily pinpoint the exact point of the leak. In conducting a test, it took right at twenty minutes to test each of the connections within my system and identify which connections had leaks. The actual repairs of the leaks around an hour. Before fixing though I timed the amount of time it took a friend to use the soapy water method to detect the same leaks.

The soapy water method timed in at around thirty-five minutes for the same number of connections. This was due to a few of the fittings needing to be tested multiple times because of small leaks. It then took an additional fifteen minutes to wipe up all the soapy water that was now dripping down the air line and around the fittings.

While both methods found the same leaks and the ULD performed the task quicker and without any cleanup required, the true focus was on all leaks being repaired. My system has a dozen connection points for a two outlet compressed air system that are regulated and filtered at a single point. This system was draining a 30 gallon tank within a few hours which costs me every time I used my compressor and did not shut off the valve that shuts off the system.

This burden on my electrical bill was removed with less than two hours of labor and I can now leave the compressor fully charged and have air as soon as I need it rather than having to wait for the tank to charge up. Had this been in a production environment the cost could have crippled production resulting in catastrophic.

If you would like to discuss how leaks within your system can easily be found by using the ULD or would like to learn more about the other five steps in our Six Steps To Compressed Air Optimization, contact an Application Engineer.

Brian Farno
Application Engineer
Ph. 1-513-671-3322
BrianFarno@EXAIR.com
@EXAIR_BF

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

EXAIR Air Nozzles – Here’s Their Simple ROI

Return on Investment, or ROI, is the ratio of profit over total investment.  Many people use it to check stocks, financial markets, capital equipment, etc.  It is a quantitative way in determining the validity for an investment or project.   You can use the ROI value to give a measurable rate in looking at your investment.

For a positive ROI value, the project will pay for itself in less than one year.  Any negative values would represent a high-risk investment.  In this blog, I will compare the ROI when replacing a ¼” NPT open pipe with a model 1122 2” Flat Super Air Nozzle.  Let’s start by looking at Equation 1 to calculate the Return on Investment:

Equation 1:  ROI = (Total annual savings – Total Project Cost) / Total Project Cost * 100

The second part of the equation, Total Project Cost, is the cost of the nozzles plus the labor to install them onto the machine.  The model 1122, 2” Flat Super Air Nozzle, has a price of $70.00 each.  The cost of a ¼” NPT Pipe that is roughly 2” long is around $1.50 each.  What a difference!  How could EXAIR been in business for over 35 years?  Let’s continue on with the Return on Investment…

The amount of time required to install the nozzles to the end of a pipe is 1/2 hour (generously).  The labor rate that I will use in this example is $75.00 per hour (you can change this to your current labor rate).  The labor cost to install a nozzle is $35.00.   The Total Project Cost can be calculated as follows: ($70 – $1.50) + $35.00 = $103.50.  The next part of the equation, Total annual savings, has more complexity in the calculation, as shown below.

As a reference, EXAIR Super Air Nozzles for compressed air would be considered like LED light bulbs for electricity.  The open pipes and tubes would represent the incandescent light bulbs.  The reason for this parity is because of the amount of energy that the EXAIR Super Air Nozzles can save.  While LED light bulbs are a bit more expensive than the incandescent light bulbs, the Return on Investment has a high percentage, or in other words, a short payback period.  On the other hand, the open pipe is less expensive to purchase, but the overall cost to use in your compressed air system is much much higher.  I will explain why.

To calculate the Total Annual Savings, we need to generate a blow-off scenario (You can use your actual values to calculate the ROI for your project).  In this example, I will compare the ¼” NPT open pipe to the 2” Flat Super Air Nozzle.  (The reason behind this comparison is that the model 1122 can screw directly onto the end of the 1/4” NPT pipe.)   The amount of compressed air used by a 1/4” NPT open pipe is around 140 SCFM (3,962 SLPM) at 80 PSIG (5.5 Bar).  The model 1122 has an air consumption of 21.8 SCFM (622 SLPM) at 80 PSIG (5.5 Bar).  At an electrical rate of $0.08 per Kilowatt-hour, we see that the cost to make compressed air is $0.25 per 1000 standard cubic feet, or $0.25/1000SCF.  (Based on 4 SCFM per horsepower of air compressor).

To calculate an annual savings, let’s use a blow-off operation of 8 hours/day for 250 days a year.   Replacing the ¼” NPT open pipe with a model 1122, it will save you (140 SCFM – 21.8 SCFM) = 118.2 SCFM of compressed air.  To put this into a monetary value, the annual savings will be 118.2 SCFM *$0.25/1000SCF * 60 Min/hr * 8hr/day * 250 day/yr = $3,546/year.  Now if you have more than one blow-off spot in your facility like this, imagine the total amount of money that you would save.

With the Total Annual Cost and the Project Cost known, we can insert these values into Equation 1 to calculate the ROI:

ROI = (Total annual savings – Total Project Cost) / Project Cost * 100

ROI = ($3,546 – $103.50) / $103.50 * 100

ROI = 3326%

With a percentage value that high, we are looking at a payback period of only 9 days.  You may look at the initial cost and be discouraged.  But in a little over a week, the model 1122 will have paid for itself.  And after using it for just 1 year, it will save your company $3,546.00.  Like with any great idea, the LED light bulb clicked on in my mind.  What could be the total savings if you looked at all the blow-off applications in your facility?

EXAIR Nozzles

In my experience, a loud blowing noise from your equipment is generally coming from an open pipe or tube.  With these “cheap” ways to blow compressed air, it will cost your company a lot of money to use as shown in the example above.  If you would like to team up with EXAIR to set up ways to increase savings, improve productivity, and increase safety, you can contact an Application Engineer to get started.  It can be as simple as screwing on a Super Air Nozzle.

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

Memorial Day 2019

 

Tech Sergeant Adrian Villa, 419th Fighter Wing places a flag with her daughter, Presley Wigman, at the Veterans Memorial Cemetery in Camp Williams, Utah.

This is the weekend, Memorial Day weekend, my family visits one of our local cemeteries and deliver flowers to the graves of veterans including a handwritten note of thanks from the kids in our 4H club. Others at EXAIR will join parades, watch parades, run a Memorial Day 10K, and gather with friends and family.

It is easy to enjoy the extra day off work and recognize how well we grilled those steaks or use the extra day to plant the garden, seal the deck, powerwash the walkway, hang out at the pool, have a beer and relax.

It is slightly harder to pay respects and/or recognize the sacrifice of our veterans who lost their lives in order for us to choose which of the above leisures we would like to enjoy. But, let me encourage us all to take a moment to look for and attend a ceremony, parade, or event focused upon these veterans. They deserve our recognition and respect.

Whatever you choose to do this weekend, enjoy yourselves, love one another, and remember to remember our veterans who have lost their lives serving the United States of America.

Enjoy the weekend,

The EXAIR team

 

Thank you to Cynthia Griggs for the above image (U.S. Air Force photo by Cynthia Griggs).

 

OSHA Safety, Efficiency, and Flexibility from Engineered Compressed Air Nozzles

Throughout my years here at EXAIR as well as my years in the metal cutting industry, one of the most common quick fixes I see in production environments for compressed air blowoffs in a process is an open copper pipe that is contorted into a position, pinched at the end, and more often than not kinked from repositioning. I call this a quick fix because it does blow air, more often than not it will get production up and running, but it does not meet or exceed OSHA standards for safety and is an inefficient use of compressed air. [OSHA Standards 29 CFR 1910.242(b) and 29 CFR 1910.95(a)]

EXAIR Super Air Nozzles that are easy replacements for 1/8″ and 1/4″ Copper pipe.

The first engineered solution I could offer to prevent any costly OSHA fines and to lower the ambient noise level caused by these blowoffs is to implement an EXAIR Engineered Air Nozzle. We offer a wide variety of nozzles ranging from a 4mm thread up to a 1-1/4″ NPT thread. With this wide range comes a wide variety of forces and flows as well.

Today, I would like to focus on the common sizes of copper blowoffs which are 1/8″ and 1/4″. To simply adapt a nozzle to copper line a compression fitting can be easily sourced, often from EXAIR, and convert the copper tubing in place to an NPT threaded outlet for easy installation of an EXAIR nozzle. More often than not a compression fitting is how the copper tubing is tied into the machine’s compressed air system.

We have a total of 37 engineered air nozzles from stock that will easily fit a compression fitting which goes to a 1/8″ NPT or 1/4″ NPT thread. Several of these are also adjustable through a gap adjustment or a patented shim adjustment to vary the force and flow out of the nozzle from a forceful blast to a gentle breeze in order to me your application needs. What if you want to eliminate the copper line and compressions fittings?

EXAIR offers a replacement option for the ever-common copper tube that is more robust and does not require a tool to be properly repositioned. We currently offer twenty-four different models of our Stay Set Hoses that can be easily connected to any of the nozzles mentioned above. The lengths that are available are 6″ (152mm), 12″ (305mm), 18″ (457mm), 24″ (610mm), 30″ (762mm) and 36″ (914mm).

These lengths are available with two separate connection options. 1/4″ MNPT x 1/4″ MNPT or 1/4″ MNPT x 1/8″ FNPT. The Stay Set Hoses can easily be bent by hand into position for a precise placement of the air pattern from the engineered nozzle attached to it. This permits operators a tool free adjustment for fast and reliable location to keep production up and running. They can also be paired with Magnetic Bases.

EXAIR Magnetic Bases are available in single outlet or dual outlet configurations. Both include a 100 lb. pull magnet that will hold tight to any ferrous metal surface for secure mounting, as well as a quick 1/4 turn miniature valve on each outlet. This permits independent customization of the force our of each output for the dual outlet mag base. Each magnetic base offers a 1/4″ FNPT inlet port and outlet port. We offer these with any of combination of the Stay Set Hoses mentioned above as well as any of the Super Air Nozzles mentioned above.

Mag Bases come with one or two outlets. Stay Set Hoses come in lengths from 6″ to 36″.

The Super Air Nozzles, Stay Set Hoses, and Magnetic Bases can be easily combined before they ship to your facility to make a complete blowoff station that is easily installed and adjusted to fit any of the needs your process may have for a point of use blowoff. If you want help determining how much compressed air you would save by replacing the open pipe blowoffs with an engineered solution like a Stay Set Magnetic Base Blowoff System please contact myself or any Application Engineer here at EXAIR.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

 

Six Steps to Optimization, Step 4 – Turn Off Your Compressed Air When Not in Use

Step 4 of the Six Steps To Optimizing Your Compressed Air System is ‘Turn off the compressed air when it isn’t in use.’  Click on the link above for a good summary of the all the steps.

6 Steps from Catalog

Two basic methods to set up a compressed air operation for turning off is the ball valve and the solenoid valve. Of the two, the simplest is the ball valve. It is a quarter turn, manually operated valve that stops the flow of the compressed air when the handle is rotated 90°. It is best for operations where the compressed air is needed for a long duration, and shut off is infrequent, such as at the end of the shift.

manual_valves (2)
Manual Ball Valves, from 1/4 NPT to 1-1/4 NPT

The solenoid valve offers more flexibility. A solenoid valve is an electro-mechanical valve that uses electric current to produce a magnetic field which moves a mechanism to control the flow of air. A solenoid can be wired to simple push button station, for turning the air flow on and off – similar to the manual valve in that relies on a person to remember to turn the air off when not needed.

wa_solvalv
A Wide Array of Solenoid Valve Offerings for Various Flows and Voltage Requirements

Another way to use a solenoid valve is to wire it in conjunction with a PLC or machine control system. Through simple programming, the solenoid can be set to turn on/off whenever certain parameters are met. An example would be to energize the solenoid to supply an air knife when a conveyor is running to blow off parts when they pass under. When the conveyor is stopped, the solenoid would close and the air would stop blowing.

The EXAIR EFC (Electronic Flow Control) is a stand alone solenoid control system. The EFC combines a photoelectric sensor with a timer control that turns the air on and off based on the presence (or lack of presence) of an object in front of the sensor. There are 8 programmable on/off modes for different process requirements. The use of the EFC provides the highest level of compressed air usage control. The air is turned on only when an object is present and turned off when the object has passed by.

efcapp
EFC Used To Control Bin Blow Off Operation

By turning off the air when not needed, whether by a manual ball valve, a solenoid valve integrated into the PLC machine control or the EXAIR EFC, compressed air usage will be minimized and operation costs reduced.

If you have questions about the EFC, solenoid valves, ball valves or any of the 15 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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Twitter: @EXAIR_BB

About Rotary Scroll Compressors

The Rotary Scroll compressor is a popular style compressor and is used primarily for air conditioning refrigerant systems.  Recently, since it is very efficient, quiet and reliable it has been adopted by industrial air compressor manufacturer’s to expand their product offering for their smaller, high-efficiency product line.

They operate on the principle of two intermeshing spirals or scrolls with one being stationary while the other rotates or orbits in relation to it.  They are mounted with 180° phase displacement between them which forms air pockets having different volumes.  Air enters through the inlet port located in the rotating/orbiting scroll which fills the chambers and as is moved along and compressed along the scroll surfaces.

scroll compressor finalSome of the key advantages of a Rotary Scroll Compressor are:

  • Pulsation free delivery due to the continuous flow from the suction port to the outlet port.
  • No metal to metal contact thereby eliminating the need for lubrication
  • Low noise levels
  • Fewer moving parts means less maintenance
  • Energy Efficient
  • Air cooled

The largest disadvantage is they are available in a limited range of sizes and the largest SCFM outputs are around 100 SCFM.

This is exactly where EXAIR shines, we offer 15 product lines of highly efficient & quiet point of use compressed air products and accessories to compliment their limited output volume of air.  All EXAIR products are designed to use compressed air efficiently and quietly, many of which reduce the demand on your air compressor which will help control utility costs and possibly delay the need to add additional compressed air capacity.

As an example, EXAIR’s Super Air Knives deliver exceptional efficiency by entraining ambient air at ratios of up to 40:1 and they are able to deliver an even laminar flow of air ranging from a gentle breeze to exceptionally hard-hitting force.

Super Air Knife
EXAIR’s Super Air Knife entrains ambient air at a 40:1 ratio!

EXAIR’s Super Air Amplifiers are able to entrain ambient air at ratio’s up to 25:1.  The model 120024 – 4″ Super Air Amplifier developes output volumes up to 2,190 SCFM while consuming only 29.2 SCFM of compressed air @ 80 PSI which can easily be operated on a 100 SCFM output compressor.

Super Air Amplifier
EXAIR Air Amplifiers use a small amount of compressed air to create a tremendous amount of air flow.

For your blow off needs EXAIR’s Super Air Nozzle lineup has an offering that will fit nearly any need or application you may have.  Nozzles are available in sizes from M4 x 0.5 to  1 1/4 NPT and forces that range from 2 ounces of force up to 23 Lbs at 12″ from the discharge.  We offer sixty two nozzles that could all be operated easily from the limited discharge or a rotary scroll compressor.

nozzlescascadeosha
Family of Nozzles

If you need to reduce your compressed air consumption or you are looking for expert advice on safe, quiet and efficient point of use compressed air products give us a call.  We would enjoy hearing from you!

Steve Harrison
Application Engineer
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