An air receiver tank can streamline your compressed air system and boost efficiency but getting the sizing right can be a challenge. To select the most appropriately sized tank, you must consider the air compressor output, the flow rate, the pressure, pipe dimensions, and the type of air compressor you will use.
To help you through the complicated sizing process, this article explores every step you need to take to ensure the best safety and storage of your compressed air.
The benefits of air receiver tanks
The role of a compressed air receiver is to temporarily store air between the air compressor and the rest of the piping network. This increases the efficiency of the system by acting as a buffer, meaning everything can operate consistently, at all times.
The two primary benefits of air receiver tanks are that they accommodate sudden surges in demand and allow the equipment to continue working even while the air compressor is switched off. As a result, the efficiency of your compressed air system will be far greater.
How to size an air receiver tank
Air receiver tanks are sized by volume, measured in litres. They are available in a range of sizes, starting from as low as 20 litres to several thousand litres. To ensure your air receiver is sized correctly for your application, there are several key steps you need to take.
1. Air compressor output
As a general guideline, your compressed air receiver should have the capacity for 10 to 15 litres of tank volume for each CFM (cubic feet per minute) of compressed air. For example, if your air compressor is rated for 100 CFM, you will need approximately 1,000 to 1,500 litres of compressed air stored in your receiver tanks.
If the air receivers can adequately store more than the air compressor produces, you can be confident that your operations will always run smoothly. If, however, the receiver capacity is less than the air compressor output, the excess will have detrimental effects throughout the system.
2. Peak usage
As a starting point, work out how much air your equipment requires in cubic feet per minute, at peak usage. If the tank can store enough compressed air to cater to these surges in demand, it should be the appropriate size. If the tank capacity is the same as or below the output, it will not be enough. Operating with an air receiver that is too small will lead to wasted energy, lower productivity, and an increase in maintenance expenses.
How to calculate peak consumption
An easy method that will allow you to calculate maximum compressed air consumption, is to tally up the air demand of each tool or piece of equipment that will be operating simultaneously. You can then multiply the total approximate consumption by a utilisation factor for each individual tool.
Utilisation factor is in essence the way a tool is used and in turn, how this affects airflow. It compares the amount of time that a piece of equipment is in use to the total time it could be in use, which provides you with a good estimation of the total consumption of compressed air.
3. Consistency of airflow
If your compressed air system is prone to fluctuations in demand, it will require more air storage than one with steady, predictable airflow. Those with steady airflow, like robotic facilities, typically don’t need as much stored air because they are consistent. The air simply moves through to the application, without needing to be stored in advance.
On the other hand, systems with many fluctuations will require more storage to cater to increased activity. This extra capacity allows the system to keep up with the higher demand without losing any pressure or productivity.
4. End-use pressure requirements
If the compressed air receiver is not sized appropriately, the end-use pressure will be affected. To know which size you need, identify both the required air compressor discharge pressure and the required end-use pressure. If the difference between these two figures is large, you will need a smaller receiver.
5. The diameter of the piping
You must also take note of the size of the pipework throughout the compressor setup as compressed air can be stored there, as well as in the receiver tank. The larger the diameter of your piping, the more air you can store, which influences the overall storage capacity. This additional space should be factored into your calculations.
This calculation will depend on the amount of piping in total, so it is worth discussing with an engineer or compressed air expert.
6. Type of air compressor
For the two main types of compressors available, reciprocating and rotary, the sizing of the receiver tanks required will be different.
Reciprocating air compressors
Reciprocating compressors require an air receiver to store compressed air and minimise pulsation. Once the receiver tank fills with enough air, the compressed air equipment can operate. When in use, compressor equipment can drain the tank quickly and time may be wasted, waiting for the tank to refill. For systems with reciprocating air compressors, sizing the air receiver correctly will help to minimise interruptions.
The standard rule for sizing an air receiver for a reciprocating compressor is to take your equipment with the highest CFM requirement at the required PSI. You then multiply the CFM requirement by 1.25 or 1.5 and round up to the nearest tank size.
Rotary air compressors
In comparison, many rotary air compressors don’t need an air receiver. Rotary screw compressors work by supplying a constant flow of compressed air, without interruption. So if your equipment requires less CFM than the air compressor produces, then an air receiver tank won’t be required.
In saying this, for some applications where more power is required for heavy-duty tools and equipment, you may choose to invest in an air receiver tank. This ensures that your air compressor will continue to operate at peak performance, even when using higher CFM tools.
Air receiver tanks in New Zealand
Even with all this knowledge, sizing an air receiver tank is complicated, time-consuming, and critical. With such a wide variety of sizes and configurations available, it’s confusing to know where to start – especially when your choice will affect the efficiency of your operations.
To ensure your system is set up for optimal performance, speak to our compressed air experts for advice tailored to your needs. We will partner with you to find the most suitable air receiver to accompany your compressor setup, selecting from our high-quality range of PneuTech air receivers designed for compressed air, nitrogen gas, or oxygen.
All of our air receivers are manufactured according to stringent CE Standards, certified to meet New Zealand seismic requirements, and come with paint, galvanised, or stainless steel finishes. Available in sizes from 270L to 20,000L, you’re sure to find a solution that works for you.
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