Precautions for use of self-priming pump

Use of self-priming pumps
I. Inspection before preparation
1. This series of self-priming pumps are lubricated with high-quality calcium-based butter and No. 10 motor oil respectively according to the working condition of the pump. If the butter-lubricated pump should be regularly filled with butter in the bearing box, the oil-lubricated pump should If the oil level is insufficient, add more.
2. Check whether the liquid stored in the pump casing is higher than the upper edge of the impeller. If it is insufficient, you can directly inject the liquid into the pump body from the liquid inlet on the pump casing. The operation should not be started when the liquid storage is insufficient. Otherwise, it will not work properly and will easily damage the mechanical seal.
3. Check whether the rotating parts of the pump are stuck.
4. Inspect the pump feet and nuts at the joints for looseness.
5. Check the coaxiality and parallelism of the pump shaft and the motor shaft.
6, check the inlet pipeline for leaks, if there is a leak, you must try to eliminate.
7. Open the valve of the suction line, and slightly open (not fully open) the outlet control valve.
Second, start and operation
1. Jog the self-priming pump and pay attention to whether the steering of the pump shaft is correct.
2. Pay attention to abnormal sounds and vibrations during rotation.
3. Pay attention to the pressure gauge and vacuum gauge readings. After the pressure gauge and vacuum gauge readings have stabilized after a period of fluctuation, it indicates that the pump has been filled with liquid and entered the normal infusion operation.
4. Before the pump enters the normal infusion operation, that is, during the self-priming process, special attention should be paid to the rise of the water temperature in the pump. If this process is too long and the water temperature in the pump is too high, stop the pump to check the cause.
5. If the temperature of the liquid in the pump is too high, which causes self-priming difficulties, you can temporarily stop the machine and use the liquid in the discharge pipe to flow back to the pump or add liquid to the pump body to add liquid directly to the pump to make the pump The internal liquid cools down and then starts.
6. If there is strong vibration and noise in the pump during work, it may be caused by cavitation in the pump. There are two reasons for cavitation: first, the inlet pipe flow rate is too high, and second, the suction stroke is too high. When the flow rate is too large, the outlet control valve can be adjusted to increase the pressure gauge reading. When the inlet pipeline is blocked, it should be eliminated in time; when the suction stroke is too high, the installation height of the pump can be appropriately reduced.
7. The pump is stopped for some reason during the work. When the pump needs to be restarted, the outlet control valve should be slightly opened (not to be fully closed). This will help the gas to be discharged from the spit during the self-priming process and ensure that the tip is light Started under the responsibility of.
8. Pay attention to check the piping system for leakage.
Third, stop the pump
1. The gate valve on the discharge pipe must be closed first.
2. Stop the pump.
3. In the cold season, the fluid stored in the pump body and the water in the bearing body cooling chamber should be emptied to prevent freezing cracks.
Self-priming pump maintenance and disassembly
The pump is characterized by simple and reliable structure and durability. Under normal conditions of the pump, it is generally not necessary to take it apart for maintenance. When the fault is found, it can be removed at any time.
1. Pay attention to several main parts when maintaining the pump:
A. Rolling bearings: When the bearings wear to a certain extent after long-term operation, they must be replaced.
B. Front seal ring and rear seal ring: When the seal ring is worn to a certain extent, it must be replaced.
C. Mechanical seal: Generally, the mechanical seal should not be disassembled and inspected without leakage. If there is a serious leak at the leak at the lower end of the bearing body, the mechanical seal should be disassembled and inspected. When assembling and disassembling the mechanical seal, you must handle it gently, pay attention to the cleanness of the mating surface, protect the mirror surfaces of the static ring and the moving ring, and do not knock or collide. The main cause of leakage due to mechanical seals is the friction of the mirror surface of the friction pair. The repair method: the end surface of the friction pair can be ground to restore the mirror surface. Another cause of mechanical seal product leakage is improper installation of O-rings or aging. In this case, the O-ring needs to be replaced for reassembly.
2. Pump disassembly sequence:
A. Remove the motor or take off the coupling.
B. Remove the bearing body assembly, check the radial clearance between the impeller and the front ring, and check whether the impeller nut is loose.
C. Remove the impeller nut, pull out the impeller, and check the radial clearance between the impeller and the rear seal ring.
D. Loosen the set screw of the mechanical seal, pull out the moving ring part of the mechanical seal, check the fit of the end faces of the dynamic and static rings, and check the seal of the O-ring.
E. Unscrew the set screw of the coupling and pull out the coupling.
F. Remove the bearing end cover and remove the pump shaft and bearing.
G. Assemble in reverse order during installation.

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