Know-a-Compressor » Calculation of Pump Up Time OR a Way to Check the Efficiency of an Air Compressor


Calculation of Pump Up Time OR Check Efficiency of an Air Compressor

By Rajkaran Chawla : Published on 20 June 2016 : Updated on 13 August 2016

How to know if an air compressor is delivering the promised CFM levels?


How to check the efficiency of an Air Compressor?


How to calculate the time an air compressor will take to fill up a particular air receiver / tank size?

By efficiency we mean is the compressor delivering the same CFM that it was delivering when you purchased it. One of the ways to check the efficiency of an air compressor is by checking the pump up time. We have generated a free tool below which can give you the below 2 answers if filled out correctly.

1) If you want to know the approximate time a compressor will or should take to fill up an air tank at a particular pressure. You need to know the following variables.

a. Volume of Air Tank in Liters only. (If you know the other units of Volume you can convert it to Liters using our Unit Converter)

b. Actual CFM of the Air Compressor: Now here please note that this should be the Free Air Delivery Values which may be mentioned on the brochure of manufacturers.

c. Final Pressure in the Tank in PSIg (This can be the cut-off pressure or unload pressure of the compressor) Therefore by the help of this tool you will be able to find out the time a compressor takes to fill a particular size air receiver at a particular pressure.

d. Initial Pressure in the Tank in PSIg (What was the initial pressure in tank before you started this test) If the tank was empty then it is ‘0’ PSIg)

2) If you know the time by physical checking and want to know what is the actual CFM of the compressor. You need to know all the above variables except the Actual CFM and you will need to physically check the time the compressor has taken to fill a particular air receiver at a particular pressure.

We have used this tool a number of times in various projects and all installations of the compressor after using this tool have been successful.

Please note that this tool will give you the accurate answers assuming that the compressor is located at Sea Level where the Atmospheric Pressure is the highest at 14.7 PSI. Therefore the air flow rate (CFM) will reduce or the time to fill up will increase where the Atmospheric Pressure is lower i.e. at higher altitudes.

Eg: Water Treatment Project

In usual water treatment projects, the compressed air is not continuously required. Compressed air is only used in operating the actuators and valves which open the water pipelines. Once the valves are open then it remains open for the next 20 hours or so without the further use of compressed air to shut the valve. So in such situations, it is better to give a big air receiver tank nearly 10,000 liters and a compressor which can fill that up with 125 PSIg or so in about an hour. So you can use this same tool provided below to come to a conclusion.

Do contact us if you face any issues with this below tool.