Reciprocating Compressor

Reduce the downstream pipe system back-pressure.

Hello "Guest",

In addition to the remedy as suggested by PWSlack above, you could install an interstage cooler.

If you already have an interstage cooler installed, and it is natural air convection cooled, look at replacing it with a water-cooled interstage cooler.

I do note you do not give us the ambient air temperature, along with the temperature of the compressed air as it arrives at the receiver tank, plus the actual power requirement (Electrical) and volume of air compressed, the compressed air pressure reading, plus the altitude of the compressor location, all of which have a considerable bearing on your compressor and its efficiency.

Thus it is impossible to calculate properly the efficiency of your 2-stage compressor, at present, and any figures presented would therefore, just be guesses.

Kind Regards....

our compressor has both intercooler and after cooler (water Cooling)

i have conducted volumetric efficiency test by pump up capacity method ,which requries filling the reciever by compressed air and noting down the time requried to fill the reciever at rated pressure .

by using the formula efficiency has been calculated.

as per my knowledge efficiency can be improved by -

removing the fouling of intercooler.

if requried then changing the piston ring

controlling leakages.

apart from these i would like to know is there any other improvement method.

thanks.

Cool the Intake air to 32 deg.f. and your efficiency would increase, plus you would get rid of a lot of water in the system.

However, it might be as expensive as adding another compressor setup.

Don't forgot your valves!!!!

Valve slip means reversed gas flow through the valves before they have had time to seat at the end of the piston stroke. Obviously, this volume loss can occur through both intake and discharge valves. Minimum slippage occurs in a responsive valve; one that has minimum inertia so that the moving element can easily be controlled by air flow. Slippage is usually much less through intake valves than through discharge valves. In the latter, differential pressure across the valve increases rapidly as the piston reaches dead center, so that if the valve does not respond instantaneously, high pressure gas naturally returns through the valve before it seats.

Also - Piston ring leakage!!!!!!!!!

In my last post I did not mention about compresion systems problems ( valves, piston rings, rider rings, packing, etc ). Assume this cheks are performed and we spoke in principle about volumetric efficiency improving.

why do you even care about volumetric efficency, its not a waste of energy (or so small it doesn't matter to engineers). Increasing VE will mean a higher throughput and higher energy.

The VE on a machine is a function of the cylinder clearance, the gas properties and ratios. You have very little if any controls over these variables. You CAN COMPENSATE for a low VE by increasing suction poress or decreasing temp. You can change vales on the suction stage that will lower pressure drop which is the same as increasing the suction pressure.