In order to ensure the safe and good operation of multi-stage centrifugal pumps for a long time,it is not only necessary to choose centrifugal pumps reasonably,but also to use centrifugal pumps reasonably and maintain them correctly.In order to ensure the normal operation of the centrifugal pump at any time and under any circumstances,it is necessary to do a good job in daily maintenance and mandatory maintenance of the centrifugal pump.
01 Main contents of daily maintenance:
The daily maintenance work of centrifugal pumps mainly includes the following points:
The outlet pressure,current,bearing temperature rise,and vibration of the pump should be regularly checked,and the operation records and equipment inspection records should be filled out on time.
The temperature and quantity of cooling water should be regularly checked and recorded.
Regularly check whether the oil cup is filled with lubricating oil and add or replace lubricating oil according to the equipment lubrication requirements.
Within 8 hours of stopping the pump,it is necessary to turn it for 3-5 turns and keep records.
Check for leakage at the dynamic and static sealing points of equipment and process pipelines.
Regularly(every on-site inspection by the operator),the host should be checked for smooth operation,any abnormal sounds,and any looseness in the connecting bolts and foundation bolts of each part.Daily equipment inspection and maintenance records should be kept.
Timely handle various equipment defects found and keep records,and report any unresolved issues in a timely manner.
Do a good job in cleaning the equipment.
02 Compulsory maintenance of centrifugal pumps
In addition to regular maintenance work,centrifugal pumps also require mandatory maintenance.Compulsory maintenance refers to the forced shutdown of a centrifugal pump after reaching the maintenance and operation time of each level,conducting a comprehensive inspection according to the maintenance content of each level,testing technical data,and keeping operation records.The mandatory maintenance of centrifugal pumps is generally divided into three levels:
First level maintenance:centrifugal pump operates for 1000h±24h;
Level 2 maintenance:centrifugal pump operates for 3000h±24h;
Level 3 maintenance:The centrifugal pump should be operated for 10000h±24h.
When replacing bearings in a single stage centrifugal pump,it is considered a major overhaul.As the number of times bearings are usually replaced is relatively high,the highest maintenance level for a single stage centrifugal pump is set as second level maintenance.Most of the three-level maintenance is for multi-stage centrifugal pumps.Although the prescribed time for three-level maintenance varies in different regions,the maintenance content is roughly the same.
First level maintenance content of centrifugal pump
In addition to completing regular maintenance,the first level maintenance of centrifugal pumps also includes the following tasks:
Check and adjust the sealing packing before and after adjustment to ensure that it does not generate heat or leak excessively,and that the shaft sleeve and gland are not worn.
Check the end cover screws,pump casing tightening screws,base and bearing bracket screws,and ensure that the sliding buckle is not loose.
Check the coupling and ensure that the screws are uniformly stressed and tightened.
Check the pressure gauge to ensure it is flexible and accurate without looseness or leakage.
Clean the filter screen to ensure cleanliness and smoothness.
Secondary maintenance content of centrifugal pump
In addition to completing the first level maintenance work,the following work should also be carried out:
Clean the front and rear bearing boxes,check or replace the oil and grease.
Check the wear of the sealing packing and replace it if necessary.
Check the appearance and concentricity of the coupling.
Check,clean and replace the pump bearings,and add grease.
Check the wear of the shaft sleeve seal and replace it if necessary.
Check the wear of the balance disc and balance ring,and replace them when the wear exceeds the required standards.
Check that the displacement of the pump shaft is within the specified range.
Level 3 maintenance content of centrifugal pumps
In addition to completing the first and second level maintenance tasks,the following tasks should also be completed:
Check the front and rear bearings and measure the bearing clearance.
Check and clean the impeller,guide vanes,guide vane fixing screws,and pump casing.
Measure the clearance between the impeller and the sealing ring,as well as the fit between the sealing ring and the guide.
Check and correct the fit of the pump shaft and coupling with the pump shaft.
Check the displacement between the balance disc and balance ring.
Check and adjust the concentricity of the coupling.
Conduct static balance tests on the impeller and balance plate.
Measure the vibration of the motor and pump.
