Know-a-Compressor » Free Tool to calculate the Piston Displacement (CFM or Liters per Minute) of a Piston Air Compressor
By Rajkaran Chawla : Published on 17th February 2017 : Updated on 30th March 2017
Firstly it is important to note that Piston Displacement is a mathematical calculation of the air that can be displaced when the air compressor is running. Please note that this value is not the Free Air Delivery which is a more important value to consider because Free Air Delivery is measured after the package of the machine considering all the losses. Free Air Delivery is generally less by approximately 23% to 28% from the Piston Displacement values.
In the below animation you can see how the air is being displaced when the piston moves along its stroke.
To use the below tool correctly you need to know the below aspects of the reciprocating air compressor.
1) Is this Air Compressor a Single Stage OR a Double Stage Design. If you do not know whether your machine is single or double stage – please click here to learn more about the same.
2) How many Cylinders in the machine act as the first stage of the compressor. In simpler terms how many cylinders have suction inlet filters from where the atmospheric air enters the compressor.
3) Is this particular cylinder a single acting or a double acting one. All of the reciprocating compressors in the small range that is 0.5 to 30 HP are Single Acting machines. Some of the machines above this range are double acting. If you do not know what is Double acting then you probably do not have that kind of a machine. But if you want to know more about Double acting machines and the piston displacement (CFM) calculation for that then please write to us.
4) What is the Bore of this first stage cylinder. Bore is the internal diameter of the cylinder. You can also say the piston diameter or the piston ring diameter if you do not know the internal diameter of the cylinder. For example you can see this manufacturers page to see the technical specifications of the air compressor how they show Bore and Stroke in the same. Please contact us if you do not know this, we can try to help.
5) What is the Stroke of the piston. Stroke is the distance the piston travels inside the cylinder. You may have to see the brochure or manual of the compressor to know this. Please contact us if you do not know this, we can try to help.
6) What is the compressor RPM or the RPM of the flywheel of the compressor. Note that we are not asking for the motor RPM here. You may have to see the brochure or manual of the compressor to know this. Please contact us if you do not know this, we can try to help.
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