Maintenance And Disassembly/Assembly Of Self-Priming Pumps

This pump features a simple, reliable, and durable design. Under normal operating conditions, frequent disassembly for maintenance is generally unnecessary; faults can simply be rectified as they arise.
1. Key areas requiring attention during maintenance:
A. Rolling bearings: These must be replaced when wear reaches a certain level after prolonged operation.
B. Front and rear seal rings: These must be replaced when wear reaches a certain level.
C. Mechanical seal: Generally, the mechanical seal should not be disassembled for inspection unless leakage occurs. If significant leakage appears at the drain port beneath the bearing housing, the mechanical seal must be disassembled and inspected. Handle the mechanical seal components with care during assembly and disassembly; ensure mating surfaces are clean, protect the mirror-like finish of the stationary and rotating rings, and strictly avoid impacts or knocking. Leakage is primarily caused by scoring or scratching of the friction pair's mirror-like faces. Repair involves lapping the end faces of the friction pair to restore the mirror finish. Another cause of leakage is improper installation, deformation, or aging of the O-ring; in such cases, the O-ring must be replaced and the unit reassembled.
2. Pump disassembly and assembly sequence:
A. Remove the motor or disconnect the coupling.
B. Remove the bearing housing assembly; check the radial clearance between the impeller and the front seal ring, and check the impeller nut for looseness.
C. Remove the impeller nut, pull off the impeller, and check the radial clearance between the impeller and the rear seal ring.
D. Loosen the mechanical seal's set screws, pull out the rotating ring assembly, and inspect the mating of the rotating and stationary ring faces as well as the condition of the O-ring seal.
E. Unscrew the coupling's set screws and pull off the coupling.
F. Remove the bearing end cap, then remove the pump shaft and bearings.
G. Reassemble the pump by following the steps in reverse order.