Hello,

Thank you for your question.

Normally, I would say after 40.000 running hours. With 8.000 running hours per year, that would result in 5 years. B

'after three years' is way too soon in my oppinion.. some compressors run only 1000 hours per year. After three years, they only ran 3000 hours. Many compressor are still running happily after 20 years without overhaul..

Also, I have seen compressor with many more than 40k running hours without breakdown. But I have also seen compressor breaking down at only 15k or 20k running hours. It depends.

It is very machine specific and hard to give an exact number. Is also just depends on the machine sometimes.. some machines simply last longer for no apparent reason..

But mainly it depends on the following:

1)How often does the machine start and stop? For rotary screw air compressors, it is best to run, run, run, run.. 24 hours a day... 365 days a year.

In fact.. the compressor that are only stopped twice a year for maintenance (and run 24/7 the rest of the year) are the best performing compressors most of the time..

Judging from the number and type of machine you have, My guess is your compressors mostly run 24/7, right?

2. Running conditions. Do the compressors run very cold or very hot? Too hot and the compressor oil will degrade. Too cold, and you get problems with water condensation. If your compressors run with an element outlet temperature of 80 - 90 degrees Celsius, that would be best.

If the compressor are installed in a very dusty place, the dust will result in extra wear and tear on the rotors and the bearings.

3. Maintenance. How often do the compressor receive their maintenance? Is the oil replaced in time? Is the correct oil used .. etc..

Taking SPM measurements of the bearings can be a big help. But again, this doesn't give us a hard 'deadline' to do a complete overhaul.

The absolute value (dB) of the measurement is not that important. You can't say '45 dB is ok, but over 50 dB you need to overhaul the compressor'.

The thing you need to look for is the trend. Compare year over year the measurement data. If the values stay the same, all is ok. If the values rise slowly.. no problem.

If the values suddenly rise sharply, pay attention. Do you hear any abnormal noise or feel vibrations?

In my experience, the SPM will slowly rise higher and higher during the years, no problems... But when the values then suddenly drop, it is ready to break down any time, and it's time to overhaul the machine.

Hope this was of any help. If you need any more info, just let me know :) Good luck!

Hi,

We have IR make 132 kW Screw Compressor. The element bearings are getting seized very often. Replaced the element bearing for 2 times. Replaced Element complete for 1 time. Still the same problem is repeating. We have clean ventilation. Checked most of the parameters for any abnormality. Found everything was fine. Still the problem is not solved. Can you suggest any other options to solve this problem.

Thanks in advance

KRR KUMAR