Leakage is one of the common faults of the D-type multi-stage clean water pump. When the pump is working, if there is no sealing device between the pump casing and the shaft, the medium will flow out from there. If it is a toxic and harmful transmission medium, then Will cause bigger and bigger. In the case of high working conditions, it is necessary to choose the D-type multi-stage clean water pump to be mechanically sealed to achieve a matching flushing scheme to achieve good sealing performance. At the same time, good long service life is also impossible for packing. Therefore, solving the leakage of the D-type multi-stage clean water pump is a very important factor to ensure the long-term stable operation of the pump. The reasons for leakage of D-type multi-stage clean water pump are mainly from the following aspects.
1. Leakage during installation static test
If the leakage is small, there are mostly problems with the moving or static ring seals: when the leakage is large, it indicates that there is a problem between the moving and static ring friction pairs. Based on the preliminary observation of the leakage and the judgment of the leakage location, the manual cranking observation, if there is no obvious change in the leakage, there is a problem with the static and dynamic ring seals: there are problems with the friction pair of the dynamic and static rings; the dynamic ring seals are problems, Problems such as failure of static ring seals. In addition, leakage channels can also exist at the same time, but generally there is a primary and secondary difference. As long as you observe carefully and are familiar with the structure, you will be able to make a correct judgment.
2. Leakage during trial operation
After the static test, the centrifugal force generated by the high-speed rotation of the multi-stage clean water pump will inhibit the leakage of the medium. Therefore, if the seal failure between the shafts and the end cover is excluded, it is basically caused by the damage of the dynamic and static ring friction pairs.
The main factors that cause the failure of the friction pair seal are:
①During operation, due to abnormal phenomena such as evacuation, cavitation, holding pressure, etc., a large axial force is caused, which separates the contact surfaces of the dynamic and static rings; the compression is too large when the mechanical seal is installed, which causes serious wear and tear on the end face of the friction pair. Bruise
②The sealing ring of the moving ring is too tight, and the spring cannot adjust the axial floating amount of the moving ring;
③The sealing ring of the static ring is too loose. When the moving ring floats axially, the static ring is separated from the static ring seat;
④ There are granular substances in the working medium, and the friction pair is entered during operation to detect the dynamic and static ring sealing end faces;
⑤ The design and selection are wrong, the seal end face pressure is low, or the seal material has a large cold shrinkage, etc. The above phenomenon often occurs during trial operation, and sometimes it can be eliminated by appropriately adjusting the static ring seat, but most of them need to be disassembled and replaced, and the seal is replaced.
3. Sudden leakage during normal operation
The sudden leakage of the D-type multi-stage clean water pump during operation is mostly caused by large changes in working conditions or improper operation or maintenance.
① Evacuation, cavitation, or holding pressure for a long time, resulting in damage to the seal;
②The actual output of the pump is too small, a large amount of media circulates in the pump, and heat accumulates, which causes the media to vaporize and cause the seal to fail;
③The return flow is too large and the seal is damaged;
④For a long time out of service, the friction pair will tear the sealing surface due to adhesion;
⑤ Increase in corrosive, polymerizable and gelling substances in the medium;
⑥Ambient temperature changes sharply;
⑦ Frequent changes or adjustments in working conditions;
⑧ Sudden power failure or shutdown due to failure, etc. If the hydraulic pump leaks suddenly during normal operation, if it cannot be found in time, it will often lead to larger accidents or losses, which must be paid attention to and effective measures must be taken.
For all of the above leakage situations, the corresponding solutions should be selected according to the problem, and if it can be replaced, it can be replaced, and if it can be repaired, it can be repaired. Do not make minor repairs and make the centrifugal pump use for a longer period of time, and then overhaul it only when major problems occur.
