Analysis of the reasons for rotor sweep in Roots blowers!
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The Roots blower in this unit is of model RRE-200, with a flow rate of 88.5 m3/min and an exhaust pressure of 78.4 KP. On July 17, the worn impeller and casing were repaired (the wear was located in the middle of the impeller and the middle part of the casing). After the repair, the blower rotated smoothly and operated normally. On the 31st, the maintenance workshop was notified to carry out further repairs, but the blower would not rotate when tried on-site. It is suspected that the impeller is stuck; no disassembly inspection has been carried out yet. Now, I would like to discuss this issue with everyone on the forum in order to determine the cause of the problem. I suspect that the outlet pressure relief valve does not have overload protection; it fails to release pressure, which leads to an increase in the machine’s temperature and operating pressure, and as a result the impeller deforms. I’d like to hear everyone’s suggestions, thank you.
This is mainly to check the data from the last maintenance
There are 20 clearances between the impeller and the casing, and the fan operates with normal vibration.
An accurate conclusion can only be reached through step-by-step inspection. Have you considered all the possible factors? After all, safety valves are installed on most exits, so the idea that overpressure is to blame seems rather far-fetched. The problems identified during the last inspection were wear marks on the part that rotates at the intermediate section; it is necessary to find out the cause of these wear marks. Could the bending and deformation of the rotor be responsible for them? It is recommended to focus on identifying the causes of wear in the areas that were inspected for the first time. Should we check if the intake filter is damaged? Air quality dust? Gas structure? ? ? It’s just a suggestion, for reference only.
Are those on the shaft journals signs of wear? The pressure buildup at the outlet is unlikely to cause damage to the rotor. Damage may result from a lack of oil in the bearings, or from damage to the synchronizing gears; misalignment of the rotor can also lead to wear such that the rotor cannot rotate
The probability of pressure buildup at the outlet is too low to be considered. It is recommended to look for the cause from a mechanical perspective