Marine centrifugal pump balancing device failure and solution
Most marine marine centrifugal pumps on ships use thrust bearings, balance holes and balance pipes to withstand and balance the axial force of the rotor. This balance method ensures that the balance hole and the balance pipe communicate with each other during maintenance, and the seal around the balance chamber The gap is within the range of the pump to balance the axial force. However, for some devices that use the balance disc (ring) to automatically balance the axial force, strict and serious inspections should be carried out. The adjustment and repair should have normal clearance and contact area between the balance disc and the balance seat or between the balance rings to ensure balance. The device automatically balances the axial force of the rotor. If it is checked that the round end face of the balance disc (ring) is beating or tilting too much, the red lead oil can be used to find the convex part on the platform or between the disc rings, and then shaved, and then coated with a fine grinding paste. Light, make the balance plate (ring) surface smooth and smooth until it can be tightly touched. It can also be adjusted by adjusting the gasket. If it cannot be adjusted or adjusted, replace the faulty balance plate or balance seat.
Fault and solution of marine centrifugal pump shaft seal device
1. Water-sealed packing shaft seal
In the packing shaft seals and water-sealed packing shaft seals of centrifugal pumps, oil-filled cotton and linen fillers are generally used. After a period of use (especially after long-term deactivation), the filler loses its elasticity and lubrication, resulting in loss of elasticity and lubrication. Air or large leaks in the pump. The specific methods for repairing the shaft seal are:
1 If the aging loses elasticity, deterioration, deformation, chipping and severe wear when the seal is inspected, it must be replaced;
2 If the surface of the packing bushing is scratched, worn or slightly rusted, it can be lighted by lathe or light sandpaper. The repaired bushing allows slight scratches. If the surface of the bushing is seriously rusted, the groove marks are deep. When the wear is serious, it should be replaced;
3 Filler gland packing ring (water seal ring) and packing retaining sleeve must be measured to check the radial clearance between it and the stuffing box. It should meet the installation standard of Table 12, and the old parts are measured more than twice the installation clearance. It should also be replaced with new ones (sometimes the outer ring of the packing ring and the retaining sleeve is seriously corroded or damaged, and the gap will increase after descaling or repairing).
2. Mechanical shaft seal
Mechanical shaft seals should focus on inspection and repair of the following components:
1 The surface of the moving ring or static ring (the friction surface of both). If there are defects such as scratches and scratches, they should be ground. When grinding, the fine grinding paste can be used to grind on the platform according to the “8” shape trajectory. When one friction surface of the moving ring is damaged and it is difficult to be ground, the adjustable one end face can still be used. When both end faces are damaged, it can be turned. The damaged surface can then be used for further grinding. If the static ring and the moving ring are found to have cracks or irregularities during inspection, replace them with new ones.
2 Newly prepared or repaired static and dynamic rings. To check that the flatness of the end face (jitter) should be less than 0.03mm, place the end face of the test piece up on a smooth platform, contact the end face of the machine to be inspected with the dial gauge stylus, and then make the part smooth on the platform. If the ground rotates, depending on the size of the dial gauge, if it exceeds the specified value, it should be reground until it meets the requirements.
3 Check the surface of the shaft and bushing outside the mechanical shaft seal device. If there are defects such as rust, burrs, scratches, etc., use a lathe to rotate the light or use fine sandpaper to remove the rust spots. For repaired or renewed shafts and bushings, check the radial runout of the mechanical seal. When checking, place the shaft on the two fulcrums of the platform and install the shaft seal with the contact lens of the dial indicator. The part (when the bushing is fitted with the bushing, the contact pin touches the bushing), and then the pump shaft is smoothly rotated. The circular runout of the dial gauge should meet the standards of Table 2. If the value of Table 2 is exceeded, it is necessary to continue the repair according to the above method.
