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

Ionizing Point Best Thing for Static on Trim Scrap in Cyclone Separator

This application came in from our distributor (AYRFUL) in Argentina. They had a customer who is recycling film scraps. The scrap material is conveyed into a cyclone separator. The problem is that the scrap becomes charged with static as a result of the motions and interactions within the conveying pipe. This results in the scrap sticking to itself and to the parts of the cyclone separator inside. The problem is so bad that it becomes almost impossible to separate the material when it comes time to clear it out of the cyclone separator once clogged.

After discussing the challenges the customer faced in trying to keep their cyclone up and running, we decided to recommend that the customer utilize 4 pieces of EXAIR’s Model 7199 Ionizing Point and 1 piece of Model 7941 (4 outlet Power Supply) to neutralize the static within the cyclone.

The ionizing Points would be attached by means of inserting through the wall of the inlet pipe of the cyclone separator.

Ion Point

cyclone

The existing blower moving air into the cyclone separator will do the job of carrying the positive and negative ions into the cyclone separator and keep it and the contents at a neutral state.

If you have a similar problem, contact us to discuss the application. We would be glad to help with our full range of static eliminators to address your application issues.

Neal Raker, Application Engineer
nealraker@exair.com

Outfitting Your Receiver Tank

Intermediate storage is a key component to your compressed air system.  Intermediate storage is step five in the Six Steps to Optimizing Your Compressed Air System.  Receiver tanks can also be the difference between having to buy a new compressor or outfitting the application with a receiver tank.  Today I would like to discuss some of the accessories you might need to outfit your receiver tank with.   Below is a picture of a receiver tank that Professor Penurious has outfitted.

IMG_2314

This is a unit that we transport around the lab to help with different tests.  As you can see there are more ports than needed on the EXAIR 60 Gallon Receiver Tank, so we have installed plugs in the unused ports, while using pipe unions and ball valves to make quick and simple installation into many different areas.

IMG_2319IMG_2317IMG_2316

Another key item to have is pressure relief valve, this needs to be paired with the receiver tank to ensure you are operating within the limits of the tank.

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Another key component is a drain valve on the bottom of the unit.   This is to help drain any moisture that has accumulated in the tank over a period of use.

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The final piece that is recommended to install on an intermediate storage tank would be a pressure gauge.   This is so you can ensure the tank is holding pressure over time, along with allow you to see your operating pressure.

If you have any questions about how intermediate storage can help your compressed air system, contact us.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF