Should the standby pump be turned over?
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Generally, most facilities have more than two units of each type of centrifugal pump, with an operation mode of two in use and two as backups (or two in use and one as backup), or all units in use. For standby pumps, it is generally required to perform regular turning operations, but for those with interlocked automatic start-up functions, do the various organizations still carry out regular turning operations? Please share how you approach it
Before use, we need to turn the shaft by hand to check for any sticking; if it is difficult to turn, it cannot be used, and the cause must be identified and addressed. Regular turning of the shaft is not carried out on a regular basis, but it is necessary for large units.
Generally, we do not rotate the pump after starting it; if rotation is necessary, a bypass must be set up first.
The standby pump equipped with interlocked automatic start-up is not rotated regularly, but it needs to be switched over on a scheduled basis once a week. To perform cranking, the motor switch knob of the standby pump must be turned from automatic to manual in order to crank it; after that, the switch for the standby pump should be returned to automatic mode.
If the pump is equipped with interlocking, the on-site switch must be set to the manual position before rotating it. Large chemical plants need to regularly turn the pumps they use through rotation
Agree with the opinion from the 5th floor; if the pump has interlock functionality, the on-site switch must be set to manual mode before rotating the pump.
In my personal opinion, it is essential to turn the standby pump manually. However, it also depends on the conditions; if there is a gauge device with an automatic start pump, it must be switched back to manual mode before rotating the pump, and then switched back to automatic mode once everything is working properly. In short, the backup pump must serve as a backup! ! !
This post was last edited by pzhmotor on 2011-4-12 09:10. The purpose of rotating the pump is to check whether the bearings, lubrication, seals, etc. are in good condition before starting the pump, in order to determine preliminarily whether the conditions for starting the pump are met. Pumps that have not been in operation for a long time usually need to be turned manually. Under certain conditions, it is even necessary to do so. For example, in gas compressors, to prevent tar from sticking to the bearings after cooling, it is necessary to rotate the shaft; otherwise, there is a high risk of the machine tripping as soon as it is started up. Therefore, I believe that in practical applications, a specific decision needs to be made based on the roll-off period and process conditions.
In my opinion, the purpose of rotating the pump is to check whether the bearings and lubrication are in good condition before starting the pump, and to determine preliminarily whether the conditions for starting the pump are met. Therefore, if an on-site self-priming pump is to be turned over, it should be switched back to “manual” mode first before performing the turning, and then switched back to automatic mode once normal operation is resumed. In short, the backup pump must remain in a standby state.
If the standby pump starts frequently, there is no need for crankshaft rotation. If the standby pump starts infrequently, the interlock should be removed based on the frequency of startups, and the pump should be turned manually under safe conditions.
Prevent shaft bending； Check whether the transmission components are flexible, so that it can be started immediately in an emergency ； In winter, check whether the pump has frozen. For self-starting pumps, the cranking mode should be changed back to “manual” before cranking, and then switched back to automatic once normal operation is achieved.