After disassembling the segmented vertical multi-stage centrifugal pump, cleaning, rust removal, inspection, measurement, replacement or repair of unqualified components, and troubleshooting the pump, it should be reinstalled to restore its working structure. When reassembling, it is necessary to strictly follow the assembly sequence and assembly technical requirements, accurately control the relative position and clearance of each component, avoid component collision, and eliminate illegal operations.
Assembly sequence and technology (valves, water pumps)
The assembly sequence of segmented multi-stage centrifugal pumps is roughly opposite to their disassembly sequence, which means that the first part to be removed during disassembly should be installed last during assembly, and the last part to be removed during disassembly should be installed first during assembly. The assembly steps of segmented multi-stage centrifugal pumps in practical operation are as follows.
(1) Read the assembly drawings and refer to them at any time during the reassembly process.
The small assembly of rotor components integrates rotating parts such as pump shaft, impeller, shaft sleeve, balance disk, bearings, etc. according to their working positions. Measure, adjust or repair the radial and end face circular runout of the impeller and balance disk to meet technical requirements.
(2) According to the rotor structure, the rotor is composed of many components that are assembled on the shaft, and the relative positions of each component on the shaft are fixed with locking nuts. Therefore, the error of the contact end faces of each component (the influence of the perpendicularity of each end face) is concentrated and reflected on the rotor. If the radial runout of various parts of the rotor is large, the pump is prone to wear during operation. The purpose of small assembly of multi-stage pump rotor components is to eliminate out of tolerance factors and avoid out of tolerance phenomena caused by error accumulation during final assembly.
(3) The assembly of the suction cover, pump shaft, and first stage impeller in a segmented multi-stage centrifugal pump can generally be carried out using a vertical J reassembly method. When the pump shaft is in the vertical position, after the assembly of each stage impeller and pump casing is completed, the long rod bolts are pre tightened, and then the pump body is placed in a horizontal position on the pump axis. During the installation period, the components are installed. To prevent the pump body from tilting during reassembly, a pit should generally be dug first. The size and depth of the pit should be suitable for placing the suction cover, and the middle of the pit should be dug deeper to accommodate the pump shaft.
When assembling, place the suction cover flat in the pit, with one side of the suction chamber facing upwards. Place the pump shaft in the suction cover, install the key of the first stage impeller in the keyway on the pump shaft, lower the first stage impeller along the pump shaft, and fix it.
(4) Install the first stage guide wheel, clean the gasket groove near the outer circumference of the suction cover, apply sealant, place the newly cut gasket, and stick it with sealant. Vertically lower the first stage guide wheel along the axis, press the gasket with the convex platform, and at the same time, ensure the circumferential positioning with the suction cover, without causing any twisting angle between the first stage guide wheel and the suction cover.
(5) Install the middle section, tail section, and corresponding impellers using the same method.
