1, d-type horizontal multi-stage centrifugal pump disassembly
d type horizontal multi-stage centrifugal water pump should strictly protect the manufacturing accuracy of the parts from damage when disassembling; when disassembling the rod, each middle section should be cushioned to prevent the middle section from loosening and sinking and bending the shaft.
Precautions:
A. Drain the liquid in the pump casing;
B. If the bearing parts are lubricated with thin oil, the lubricant should be drained;
C. Remove the auxiliary pipelines that hinder the disassembly, such as balance pipes, water-sealed water pipes and other pipelines and leads
D-type horizontal multi-stage centrifugal pump disassembly sequence:
The disassembly steps of the pump should start from removing the bearing parts on the discharge side. The sequence is roughly as follows (due to the difference in the structure of the pump, the disassembly process will be slightly different)
A, unscrew the bolts on the discharge side bearing gland and the coupling nuts between the discharge section, the stuffing box body and the bearing body to remove the bearing parts;
B. Unscrew the round nut on the shaft, remove the inner ring of the bearing, the bearing gland and the stopper in turn, and then remove the packing body (including packing gland, packing ring and packing, etc.);
C. After removing the O-ring, shaft sleeve, balance plate and key on the shaft in turn, remove the spit section (including the final stage guide vane balance ring, etc.);
D. After removing the last stage impeller and key, remove the middle section (including the guide vanes); continue to remove the other stages of the impeller, middle section and guide vanes in the same way until the first stage impeller is removed;
E. After unscrewing the coupling nut between the suction section and the bearing body and the bolts on the bearing gland, remove the bearing parts (the pump coupling should be removed before this);
F. Pull the shaft out of the suction section, unscrew the fixing nut on the shaft, and remove the bearing inner ring, O-ring seal, shaft sleeve, and stop sleeve in turn.
So far, the disassembly work is basically completed, but in the above disassembly process, some parts are connected to each other. Generally, it can be removed after unscrewing the connecting bolts or nuts.
2, d-type horizontal multi-stage centrifugal pump assembly
Cleaning and inspection:
A, clean all parts with kerosene, dry in the air or wipe dry with a cloth;
B. Check the wear and tear of all parts, and replace the parts that cannot ensure normal operation.
C. Check if there is dust or rust on the pump shaft. Use a dial gauge to check the unevenness of the shaft (the radial runout value of the shaft is not greater than 8 accuracy);
D. When the sealing gap exceeds 50% of the recommended maximum value, the sealing element should be replaced.
The assembly sequence of the pump is generally reversed according to the disassembly sequence:
The assembly quality of this type of pump directly affects the normal operation of the pump, and affects the service life and performance parameters of the pump; it affects the vibration and noise of the unit. The following points should be noted during assembly:
A. The concentricity of the combined parts of the fixed part is guaranteed by the manufacturing accuracy and assembly quality of the parts. The machining accuracy and surface roughness of the parts should be protected, and bumps and scratches are not allowed. Molybdenum disulfide used as a sealant should be clean. The screws and bolts used for fastening should be evenly stressed.
B. The alignment of the impeller outlet flow path and the guide vane inlet flow path is ensured according to the axial dimensions of each part. The quality of the flow channel to the neutral directly affects the performance of the pump, so the size of the pump cannot be adjusted at will
C. After the pump is assembled and before the packing is installed, turn the pump rotor by hand to check whether the rotor rotates flexibly in the housing and whether the axial movement meets the specified requirements
D. After the above inspection meets the requirements, add packing at the shaft seals at both ends of the pump, and pay attention to the position of the packing ring in the packing chamber
