## How-To Size Receiver Tanks and Why Use Them in Your Compressed Air System

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 the operation of your compressed air system.  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 for optimum performance.

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 for this is to have a ready source of energy to increase efficiency and speeds with the ebbs and flows of electrical signals.  The same can be said for a pneumatic system with secondary receiver tanks.

To tie this into the compressed air system, if you have an area that requires a high volume of compressed air intermittently, a secondary receiver tank would benefit this type of pneumatic setup.  With valves, cylinders, actuators, and pneumatic controls which turn on and off, it is important to have a ready source of stored “energy” nearby.

For calculating a minimum 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 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 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.  So, any receiver tank with a larger volume would work as a secondary receiver tank.

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)

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.  EXAIR stocks 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 EXAIR Application Engineer.  We can restore your efficiency and speed back into your applications.

John Ball
Application Engineer
Email: johnball@exair.com

Photo: Circuit Board courtesy from T_Tide under Pixabay License

## About Dual Acting Reciprocating Compressors

When it comes to generating compressed air there are many types of compressors to utilize within a facility.  One of those types is a dual acting reciprocating compressor.  This is a type of positive displacement compressor that takes advantage of a piston style action and actually compresses air on both directions of the stroke.  Below you can see a video from a company that showcases how a dual acting compressor works and gives a good representation of how it is compressing the air on both directions of travel.

The reciprocating type of air compressor uses a motor that turns a crank which pushes a piston inside a cylinder; like the engine in your car.  In a basic cycle, an intake valve opens to allow the ambient air into the cylinder, the gas gets trapped, and once it is compressed by the piston, the exhaust valve opens to discharge the compressed volume into a tank.  This method of compression happens for both the single and double acting reciprocating compressors.

With a single acting compressor, the air is compressed only on the up-stroke of the piston inside the cylinder.  The double acting compressor compresses the air on both the up-stroke and the down-stroke of the piston, doubling the capacity of a given cylinder size.  This “double” compression cycle is what makes this type of air compressor very efficient.  A single acting compressor will have an operating efficiency between 100 cfm / 23 kW of air while the double acting compressor has an operating efficiency between 100 cfm 15.5 kW .  Therefore, electricity cost is less with a double-acting reciprocating air compressor to make the same amount of compressed air.

These compressors are ruggedly designed to be driven 100% of the time and to essentially be a Clydesdale of compressors.  They are commonly used with applications or systems requiring higher pressures and come in lubricated or non-lubricated models.

If you would like to discuss air compressors or how to efficiently utilize the air that your system is producing so that you aren’t giving your compressor an artificial load that isn’t needed, contact us.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

## Back At Ya!

This may not be big news as it happens almost every month.  EXAIR is continuing to grow our product line and this time it is something we have never done before.  This new EXAIR Engineered Solution doesn’t blow debris away, instead, it all comes back towards you.   Why would you want this you ask?  What does this new-fangled contraption look like?  Both of those questions will be answered below.

To answer the first question, why would you ever want debris to come back at you?  Well, this isn’t for just blowing any part or area out, this nozzle has been designed for a special purpose – to blow out pipes, tubes, extrusions, and even some blind holes or pockets.   This is ideal when working on a piping system that you may need to clean out and don’t want to push debris further into the system.   It is a quick and easy way to clean out chips from a saw cut operation for tubing or extrusion.  The nozzle could even be used to clean out cylinders or crank shaft openings on engine blocks.

So what is the name of this new nozzle and what does it look like?

This is it, the EXAIR model 1006SS Back Blow Nozzle.   The nozzle features a 1/4″ FNPT air inlet, a 3/4″ O.D. to fit into piping, extrusion, or holes, and two flats which allow for the use of a 5/8″ wrench to install the nozzle.   The nozzle is constructed of 316 Stainless Steel, utilizes  22 SCFM when operated at 80 psig, gives off 80 dBA and is designed for use with 7/8″ to 4″ I.D. pipe, tube, or holes.

The unit will also be available on our Safety Air Guns with Chip Shields to offer cleaning excellence and protection for the operators.  Like all of the stock EXAIR products, this is available with our 30 day guarantee.   So if you are not sure whether this nozzle will work on your application, give us a call, get one in, and put it through the paces.   If the Back Blow nozzle doesn’t meet your needs, simply let us know within 30 days from the date of purchase and we will take it back and provide you full credit.

If you want to discuss this nozzle or any other compressed air application, don’t hesitate to contact us.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

Finger Face – Tsahl Levent-Levl , Creative Commons License, Some Rights Reserved

## EXAIR Distributor Solves Problem For End User

Our Thai distributor, OilPure Management Systems, recently worked through an application with an end user in need of both debris and heat removal at a gas cylinder recycling facility.

In this application, the end user needed to remove heat and debris from the gas cylinders shown above.  These cylinders are recycled and as part of the recycling process, the previous exterior coating and labeling must be removed.  To remove the coating and labels, the cylinders are subjected to a rigorous cleaning and heating process that leaves them with debris around the O.D. of the cylinder at a temperature around 300°C.

Given the need to simultaneously remove debris and cool the cylinders, our distributor recommended a series of Super Air Knives mounted around the exterior in a hex pattern.

After travelling through the air curtain made by the series of Super Air Knives, the cylinders will have been treated for both debris and heat, preparing them for a final coating to look like the finished product shown below.

If you have a need for EXAIR products, contact an Application Engineer or consult one of our worldwide distributors.  (For an interactive map of EXAIR distributors around the world, click here.)

Lee Evans
Application Engineer
LeeEvans@EXAIR.com
@EXAIR_LE