If well maintained a rotary screw compressor can enjoy a very long life. There will of course come a point when you ask yourself - is it time to invest in a new compressor? This may be because you think your compressor has reached the end of its useful life - it’s old and you have concerns about its reliability or efficiency, or your compressed air requirements have simply changed and your existing compressor cannot efficiently meet these needs. If it is the former then it’s worth seeing if air compressor overhaul could present a cost effective way to extend your compressors life.
Most rotary screw compressors will use a lubricant to seal the airend. As a result very little wear may occur in the compressor airend itself, if it has been maintained correctly and the recommended lubricant has been used. This often means that an overhaul can return it to ‘like-new’ condition - and at a fraction of the cost of investing in a new compressor.
When do you overhaul a compressor?
A quick look at the operating instructions manual for your compressor should identify at which point an overhaul may be required. Typically this will state that an overhaul is required when the compressor has operated for a specific number of hours or years - usually whichever comes first. Alternatively you could contact the OEM (Original Equipment Manufacturer) to obtain this information.
The overhaul process
A rotary screw compressor has several major components which should be considered during an overhaul process.
To see if an overhaul is feasible, the first step would be to have the compressor inspected by a qualified compressed air Service Technician. As part of an inspection they would perform a number of tests and checks to ascertain the condition of the airend and electric motors as well as the control circuits and oil. Performing these test procedures would also allow them to estimate the cost of overhauling the compressor if practical.
Is an overhaul right for me?
If you can overhaul your rotary screw compressor you will extend its useful life. Depending on your specific circumstances, overhauling may be the most practical and cost effective option as opposed to investing in a new compressor. In addition;
- an overhaul would also be considered a Repairs & Maintenance (R&M) cost rather than Capital Expenditure (CapEx) - and in the current climate that may be far more practical.
- investing in a new compressor may become a much larger project that not only requires CapEx but from planning to delivery to installation - takes much longer to execute. If you don’t have that amount of time then overhaul may be the better option.
There will of course be circumstances when overhauling a rotary screw compressor is not the right option, for example where;
- your demand for compressed air has changed and the existing compressor is not efficiently meeting these needs
- the cost of an overhaul outways the cost of investing in a new compressor
- the compressor technology is now outdated and investing in a new compressor will bring compressed air system networking gains
- the post-overhaul efficiency will not be satisfactory. While the compressor may be suitable enough from a mechanical perspective to warrant an overhaul, you should also do a power cost analysis. As a large energy consumer, you would not only want a compressor that is reliable but one that is also energy efficient by current standards.
Summary
Where viable, overhauling can cost effectively extend the useful life of a quality rotary screw compressor, postponing the need in the short term to invest in a new compressor. The best way to determine whether you could benefit from an overhaul is to speak with your compressed air service provider who can investigate this for you.