6 STEPS To Optimizing Compressed Air: Step 5 – Install Secondary Receiver Tanks

Since air compressors require electricity to make compressed air, it is important to optimize your compressed air system. EXAIR has six simple steps, and following these steps will help you cut electrical costs, reduce overhead, and improve your bottom line.  In this blog, I will cover the fifth step –intermediate storage of compressed air near the point-of-use. 

I had a customer that was looking at a model 1122108, 108” (2,743mm) Super Ion Air Knife Kit.  The application was removing static and debris from insulated panels which they used for large refrigerated trailers.  They were worried about how much compressed air that it would use; and they were considering a blower-type system.  I went through the negative aspects like noise, cost, maintenance, and ineffectiveness with turbulent air flows.  But, when you are limited in the amount of compressed air, I had to look at another way.  Since the process was intermittent, I used the fifth step to optimize their system to use a much better solution for their application.  The cycle rate was 2 minutes on and 10 minutes off.  I was able to calculate the size of a secondary tank to help their compressed air system.   

Model 9500-60

I would like to expand a bit more about secondary receiver tanks.  They can be strategically placed throughout the plant to improve the “ebbs and flows” of pneumatic demands.  The primary receiver tanks help to protect the supply side when demands are high, and the secondary receiver tanks help pneumatic systems on the demand side.  They give additional capacity at the end of distribution lines.  Essentially, it is easier and more efficient for compressed air to travel out from a nearby source and into an application rather than traveling through long lengths of pipes from the distribution system.

For calculating the volume size for your secondary receiver tank, we can use Equation 1 below.  It is the same for sizing a primary receiver tank, but the scalars are slightly different.  The supply line for air drops will typically come from a header pipe and are generally smaller in diameter.  So, we have to look at the air restriction that 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 in Equation 1.  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 tank volume that would be needed.  The other value in the equation 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 P2P1 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. 

Equation 1:

V = T * (C – Cap) * (Pa) / (P1-P2)

Where:

V – Volume of receiver tank (cubic meter)

T – Time interval (minutes)

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

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

Pa – Absolute atmospheric pressure (Bar)

P1 – Header Pressure (Bar)

P2 – Regulated Pressure (Bar)

For this customer above, I am still working on this purchase.  But we went from a “we don’t have enough compressed air” to a “we can possibly use the better solution with the Super Ion Air Knife”.  If you find that you might be having issues with your equipment running optimally, you may be able to install a secondary receiver to your system.  EXAIR offers 60 Gallon tanks, model 9500-60, to add to those specific areas.  If you have any questions about using a receiver tank in your application, primary or secondary, you can contact an Application Engineer at EXAIR.

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

Compressed Air Receiver Tanks On The “Demand” Side

Most any air compressor is going to have a receiver tank…from the “pancake” types that might hold a gallon or so, to the large, multi-tank arrangements that facilitate both cooling and drying of compressed air in major industrial installations.  The primary purpose of these receiver tanks is to maintain proper operation of the compressor itself…they store a pressurized volume of air so that the compressor doesn’t have to run all the time.  Receiver Tanks, however, can also be used to eliminate fluctuations at points of use, especially in facilities where there might be a lot of real estate between the compressor and the compressed air consuming products.

I recently had the pleasure of discussing an Line Vac Air Operated Conveyor application with a caller.  The need was to move wood chips, from inside to outside the plant, into trailers.  The facility has plenty of compressed air to operate the Line Vacs (the application calls for several) but because the point of operation is so far from the header, they’ll need a “stash” (the caller’s words…we call it “intermediate storage” but he’s not wrong) of compressed air to keep the Line Vacs supplied for operation without any dips in performance.

Enter the Model 9500-60 60 Gallon Receiver Tank.  When an application requires an intermittent demand for a high volume of compressed air, the Receiver Tank provides intermediate storage (or a “stash” – that word’s growing on me) to prevent pressure fluctuations and the associated dips in performance.

Model 9500-60 60 Gallon Receiver Tank

The Model 9500-60 has a small footprint for where floor space is at a premium, and meets ASME pressure vessel code specifications. It comes with a drain valve so you can discharge condensate and contaminants.  A check valve (not included) can be installed upstream to maintain the tank at max pressure so it doesn’t ‘back feed’ other upstream uses.

Use of intermediate storage near the point of use is one of our Six Steps To Optimizing Your Compressed Air System.  If you’d like to find out more about getting the most out of your compressed air, give me a call.

Russ Bowman
Application Engineer
EXAIR Corporation
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Intermediate Storage Tanks & How To Size Them

When evaluating processes that utilize compressed air and adhering to the Six Steps to Compressed Air Optimization, intermediate storage proves to be a critical role coming in at step number five. Intermediate storage tanks may already be in place within your facility and often times can be implemented as modifications to aid existing lines that are struggling to maintain proper availability of compressed air to keep the line at peak performance.

EXAIR Receiver Tank in 60 Gallon Capacity

When determining whether or not a production line or point of use compressed air operation would benefit from a receiver tank/intermediate storage we would want to evaluate whether the demand for compressed air is intermittent.  Think of a receiver tank as a capacitor in an electrical circuit or a surge tank in a water piping system.  These both store up energy or water respectively to deliver to during a short high demand period then slowly charge back up from the main system and prepare for the next high demand.   If you look from the supply point it will see a very flattened demand curve, if you look from the application side it still shows a wave of peak use to no use.

Intermittent Applications are prime for rapid on/off of compressed air.

One of the key factors in intermediate storage of compressed air is to appropriately size the tank for the supply side of the system as well as the demand of the application.  The good news is there are equations for this.  To determine the capacity, use the equation shown below which is slightly different from sizing your main compressed air storage tank.  The formulate shown below is an example.

Where:

V – Volume of receiver tank (ft3 / 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)

One of the main factors when sizing point of use intermediate storage is, they are being supplied air by smaller branch lines which cannot carry large capacities of air.  That limits your Cap value. The only way to decrease the V solution is to increase your Cap. The other key point is to ensure that all restrictions feeding into the tank and from the tank to your point of use are minimized in order to maintain peak performance.

If there are intermittent applications that are struggling to keep up with the production demands within your system, please reach out and speak with an Application Engineer.  We are always here to help and we may even be able to help you lower the demand needed by utilizing an engineered point of use compressed air solution.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

Installing Secondary Receiver Tanks: Step 5 in Optimizing Your Compressed Air System

SixSteps

The 5th step in the 6 steps to optimizing your compressed air system highlights the use of intermediate storage of compressed air near the point of use. Secondary, or intermediate 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.

Compressed air receiver tanks are an integral part to many compressed air distribution systems. Compressed air is stored at a high pressure after drying and filtration, but just upstream of point of use devices. The receiver tank is charged to a pressure higher than what is needed by the system, creating a favorable pressure differential to release compressed air when needed.

Think of a compressed air receiver tank as a “battery”. It stores the compressed air energy within a system to be used in periods of peak demand, helping to maintain a stable compressed air pressure. This improves the overall performance of the compressed air system and helps to prevent pressure drop.

receiver_tank

They can be strategically placed to provide a source of compressed air to intermittent high volume compressed air applications. Rather than having to pull from the compressor, a receiver tank can be sized to provide the short-term volume of air for a particular application. In a previous post, we’ve highlighted how to calculate the necessary receiver tank based on the air consumption and duration of the application.

EXAIR offers from stock a 60-gallon receiver tank designed specifically for these higher-usage intermittent types of applications. Model 9500-60 can be installed near the point of high demand so that you have an additional supply of compressed air available for a short duration. The tank comes with mounting feet and is designed to stand up vertically, saving floor space. The tank meets American Society of Mechanical Engineers (ASME) pressure vessel code.

If you have an application in your facility that’s draining your compressed air system, a receiver tank could be the ideal solution. Give us a call and one of our Application Engineers will be happy to help evaluate your process and determine the most suitably sized receiver tank.

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