securely keyed to the shaft and adjusted to proper axial position by the shaft sleeves and external shaft nuts. The impeller is a double-suction enclosed type. It is hydraulically balanced by its inherent design. In case there is some slight residual thrust, it can be carried up by the bearing on the shaft end.
Each pump shaft is provided with two bearings mounted in the bearing housings at both ends. For single row, deep- groove type ball bearings, both of them are lubricated with grease. For babbit bushings, oil lubrication is used and cooling water is provided through the bottom chamber of the housings.
Couplings of flexible type connect the pump with the motor directly. For pumps driven by belt, there must be an intermediate bracket fitted for supporting the belt pulley.
The close running fit between the wearing rings and the impeller minimizes the leakage of water back into the suction part. The rings protect the casting form wearing and can be promptly replaced with the spare parts when they have been worn out.
The shaft sleeves extend through the stuffing boxes. They protect the shaft from wearing. The sleeves can be renewable with the spare parts after worn out.
Stuffing boxes are packed with the graphited asbestos packing. The packing must be properly pressed by adjusting the gland. Stuffing boxes are usually connected to the pump discharge with external pipe connections through which water under pressure is introduced into the boxes to have the sealing function of protecting the pump against leakage, either air leakage inward or fluid leakage outward.Ⅲ. Assembly and disassembly
(Please use the following procedures to assemble)
1. Assemble keys, impeller, sleeves, sleeve nuts packing rings, and bearing block in order on the pump shaft. Afterwards sleeve the suction seal ring, and then the bearing part and coupling.
2. Individully inspect the radial beats of the ex-