Centrifugal compressor

Personal opinion: It depends on how you go about it; it’s simply a matter of opening it up to check the degree of bending of the shaft. This does not require dynamic balancing. If there are moving parts in the rotor, such as balance assemblies or impellers, and if these parts have been removed or replaced, it is recommended to carry out this procedure.

What items do you check during maintenance? If there is no movement on the rotor, then dynamic balancing is not necessary

It has been out of use for a year, so it still needs to undergo a thorough overhaul. A comprehensive inspection is necessary, including checking the rotor’s dynamic balance, replacing the dry gas seals, inspecting the bearing shells, and examining the diaphragm gas seals

Thank you. It’s scheduled for a major overhaul; the components on the rotor haven’t been touched yet, and we’re considering whether it’s necessary to perform balance testing.

After being out of use for a year, it can be opened to check the crankshaft; if the bending amount is no more than 0.06 mm, balancing is not required.

If the rotor components have not been moved, it is recommended to first check the shaft runout with the impeller in place; if there is no significant deviation, then balancing is not necessary. Nowadays, the rotor shafts of compressors are usually rigid, and their strength is more than sufficient to prevent the rotor from bending even after being unused for a year. (My personal opinion does not represent everyone’s view.) Of course, performing dynamic balancing is quite convenient and not too time-consuming; it’s worth considering doing it just to feel at ease. There is no necessity for such a thing, nor are there any requirements or regulations stating that it must be done after being closed for a year. In fact, in many foreign design concepts for centrifugal compressors driven by electric motors, no barring gear is installed; whereas for those driven by turbines, a barring gear is provided as part of the turbine’s design. Put it another way, during the design phase it was taken into account that shutdowns wouldn’t require rotating the shafts, so the shafts are made of alloy steel, which gives them excellent strength.