The image below shows the bevel gear of the first-stage input shaft of the gearbox

Damage to the mating surfaces caused by the entry of foreign objects, bearings, and other factors that may lead to sudden shutdown.

Look at the gear in our company that’s broken. The reason is that the outlet pressure of the Roots blower is too high. It is caused by compressor vibration. Also: Since your gears have changed color, you need to consider whether the lubrication is sufficient. With just one photo, it’s difficult to conduct a root cause analysis; you need to rely on your own judgment based on the operating conditions of the compressor before it stopped working.

This incident can only be attributed to the consequences of no human intervention. The damage wasn’t caused by overpressure; it was likely due to impurities or foreign objects in the oil, or issues related to gap adjustment, which led to gradual wear. As a result, one tooth became damaged, and it’s only a matter of time before other teeth are affected as well.

This post was last edited by Xiaoyao de Xiao Yu on 2020-10-29 at 09:16. Thank you for your replies. The background regarding the damaged unit is as follows: (1) One unit has been in use for 3 years without any operational issues. Normal maintenance is sufficient. (2) Since 1 fan can only achieve a flow rate of 450 m3/h, the expanded capacity needs to reach 600 m3/h. Another unit was connected in parallel. The compressor began to fail at irregular intervals (it would break down as soon as 2 days, or up to 2 months later), and the extent of damage in each case was as shown in the diagram – complete destruction. (3) Both the supplier and I supervised the installation on-site; there’s no chance of errors with such a simple task as installation and lubrication. (Engine disassembly/wiping, complete replacement of lubricating oil). (4) Let me show you our design parameters; you might be surprised. Class 2 unit: 1st stage compression + heat exchanger + 2nd stage compression + delivery. (5) The outlet pipeline is equipped with a flow meter for flow control; the DN80 outlet pipeline narrows to DN40 at the location of the flow meter. (6) On two occasions on site, the safety valve at the unit’s outlet activated, causing a significant vibration in the unit; these intermittent activations lasted around 30 seconds before the unit was damaged beyond repair. (7) Solution: Replace the DN80 flow meter. The process requirement has been reduced from 1.4 bar at the outlet to 0.9 bar, and the setting pressure of the safety valve has been changed to 1.0 bar. Regarding the claim that it operates without human intervention, we acknowledge this: the equipment is simple and the manufacturing process is not complex; indeed, there is basically no instrument monitoring or automatic control here. But other reasons are really not right. Regarding the gaps, our factory has substantial financial resources; when the equipment broke down, we purchased two new units, which were also installed by the supplier (at that time our confidence was shattered). Both of those units broke down within 2 days. The main improvement now is the pipeline; it can be installed casually and won’t break. . . . . .

Oh, it seems to be overload caused by overpressure; interesting. This type of management is indeed rare; thanks for sharing.