Is alignment required when restarting a centrifugal pump after winter shutdown?
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I have a centrifugal pump that has been shut down for the entire winter, and now it needs to be put back into operation. Is it necessary to realign it with the motor? The centrifugal pump has a flow rate of 13,400 cubic meters per hour; it transports circulating water. The bearing type is sliding bearings, the rotational speed is 590 rpm, and the power output is 2,550 kW. Due to the excessive weight of the entire rotating assembly, it is not possible to turn the pump manually. After removing the coupling, 4 people can turn the shaft.
The flow rate is 13,400 cubic meters per hour, with a power output of 2,550 kW; the power level corresponding to this flow rate is quite high indeed. After removing the coupling, 4 people can turn the shaft – is it that tight? The power consumption is way too high; it’s necessary to find out the reason for this. For safety reasons, it’s important to align everything properly. Our pump has an outlet flow rate of 17,000 cubic meters per hour; in winter, one person is sufficient to operate it, and everything works fine, except that alignment is required after maintenance.
Your pump has an outlet flow rate of 17,000 cubic meters per hour; in winter, one person is needed to turn the pump manually. Are the pump bearings not sealed using oil-impregnated asbestos rope packing? Additionally, the weight of the shaft and that of the motor shaft add up to a considerable amount.
Not needed for small ones; used for large ones, and also for inspection and turning
When the equipment is turned on, a turning inspection must also be carried out; moreover, for equipment that is not in use, 4 people are still needed to perform the turning inspection and alignment maintenance, which is more in line with standard operating procedures.
Back to Floor 3: I’m not entirely sure whether the pump bearings are sealed with oil-impregnated asbestos rope (I personally suspect they’re not); our pumps are entirely imported, and it’s really not difficult to turn the pump – one person can do it by hand.
If a pump is not used for an extended period of time, it can indeed be difficult to turn it by hand; therefore, strict measures for turning the pump by hand must be implemented, and regular turning is necessary to avoid the situation where the pump cannot be turned when needed.
After a chemical pump has been shut down for an extended period of time, it is necessary to perform shaft turning on the pump. In the case of large chemical pumps that have been idle for a long time, it is important to check the alignment of the pump shaft and the motor shaft – this is key to proper operation.
It’s best to align it properly; if it isn’t used for an extended period, the shaft should be rotated a few times to check for any sticking issues. Also, verify whether the packing is tightened too much, or if there is friction between the impeller and the water ring
Thank you all. I understand that the standby pump needs to be rotated regularly. For pumps that have not been in use for a long time, alignment should be considered before starting them up. If rotation is not possible, it may be due to jamming or overly tight packing; appropriate measures should be taken to resolve the issue. :)
Rotating the pump is a routine task, and there is no reason to stop maintaining it just because the pump unit is out of use during winter. Regular rotation constitutes maintenance; if there are no issues with the rotation, no alignment checks are required when the pump is brought back into operation. However, for large-scale equipment, it is necessary to conduct a thorough inspection before putting it into use, covering mechanical, electrical, and instrumentation aspects.
It’s still necessary to check for alignment; it hasn’t been in use for such a long time, and moreover the turning gear is sticking, so an inspection is required to prevent equipment failures.
Generally, large pumps need to be realigned, while small pumps do not require this