Repair and maintenance of marine centrifugal pumps is to keep marine pumps in a good condition and are very important for the safety of ship. So we need to check the working condition of the marine centrifugal pump all the time, and repair it in time if there is a problem. Here introducing which common parts need to be inspected and repaired.

1. Seal ring. The seal ring is one of the main vulnerable parts of the centrifugal pump, and its performance directly affects the volumetric efficiency of the pump. After every 2000 hours of work, the matching clearance should be disassembled and inspected, and the ring with serious wear should be replaced.

2. Mechanical seal, the contact sections of the dynamic and static rings of the mechanical seals should be ground and polished. If there is roughness, the wear should be ground and polished again. If the wear is serious, it should be replaced with a new one, but it must be replaced in pairs. If the shaft sleeve (or shaft) at the shaft seal device is greatly worn or has groove marks, it should be repaired and replaced with a new one.

3. Impeller. Those who have one of the following conditions need to be replaced in time:
(1) There are deep cracks on the surface
(2) The surface has more sand holes and deep holes due to corrosion
(3) Transitional thinning of both side walls of the impeller
(4) Severe partial wear at the water inlet of the impeller
(5) If the bronze impeller is perforated, it can be repaired by brazing, and it should be replaced if it is serious.

4. Pump shaft. Generally, if the shaft is cracked or the surface of the shaft is severely worn during work, it is enough to affect the mechanical strength of the shaft and should be replaced. The pump shaft will be bent and deformed under the action of impact load or improper installation. The deformation and bending position should be checked with a dial indicator on the machine tool, and then corrected on a small press or a manual screw straightening machine.

5. Pump casing. Cracks in the pump casing and pump cover due to mechanical and thermal stress. If the crack is in a place with little pressure, drill a crack stop hole with a diameter of 3 mm at each end of the crack to reduce stress concentration; if the crack appears in a pressure-bearing place, a crack should be opened on the crack for internal and external repair welding . In severe cases, it should be replaced with a new one. The repaired casing or pump cover should be subjected to a hydraulic test (the pressure is 1.5 times the working pressure), and it can only be used if there is no leakage within 5 minutes.