Generally speaking, the comparison of leakage between the shaft sleeve extension and between the sealed end cover and the pump body is simple to detect and dispose of, but it requires detailed investigation, especially when the working medium is liquefied gas or high-pressure, toxic and harmful gas, which is relatively difficult. It is difficult to distinguish and distinguish other leaks intuitively, and it is necessary to conduct investigations, analyses, and judgments on the leakage performance based on long-term processing and repair internships in order to draw a positive conclusion.

1、 Analysis and discrimination of leakage reasons

1. The equipment leaked during static testing. After the mechanical seal equipment is debugged, a static test is usually conducted to investigate the leakage rate. If the leakage is small, it is mostly due to doubts about the sealing ring of the dynamic or static ring; When there is a large amount of leakage, it indicates that there is a problem between the dynamic and static rings. On the basis of investigating the leakage amount and identifying the leakage location at the beginning, manually turn the wheel to investigate. If there is no significant change in the leakage amount, there are doubts about the static and dynamic sealing rings; If there is a significant change in the amount of leakage during turning, it can be concluded that there is a problem with the collision between the dynamic and static rings; If the leaked medium sprays along the axial direction, there are mostly doubts about the dynamic ring seal. If the leaked medium sprays nearby or leaks out from the water cooling hole, it is mostly due to the failure of the static ring seal. In addition, leakage channels can also exist together, but there are usually primary and secondary differences. As long as the investigation is detailed and the layout is known, it will definitely be able to distinguish correctly.

2. Leakage during the trial assignment. After static testing, the centrifugal force generated by high-speed rotation during operation of the pump's mechanical seal will suppress the leakage of the medium. Therefore, during the trial operation, mechanical seal leakage is fundamentally caused by damage to the dynamic and static ring collision pairs after the failure of the cleaning shaft and end cover seals. The primary factors that cause the failure of the secondary seal in conflicts are:

(1) During operation, abnormal phenomena such as looseness, cavitation, and pressure build-up result in significant axial force, causing the contact surfaces of the dynamic and static rings to separate;

(2) Excessive compression during mechanical sealing of the equipment results in severe wear and abrasion of the conflicting end faces;

(3) The sealing ring of the moving ring is too tight, and the tension spring cannot adjust the axial floating amount of the moving ring;

(4) The sealing ring of the stationary ring is too loose, and when the moving ring rises in the axial direction, the stationary ring separates from the stationary ring seat;

(5) There is granular material in the homework medium, and there is a conflict between the two during the homework. The sealing end faces of the dynamic and static rings are inspected;

(6) The selection of the description is incorrect, such as the sealing end face having a lower pressure ratio or the sealing material having greater cold shrinkage. The above phenomena often appear in trial operations, and sometimes can be eliminated by adjusting the static ring seat appropriately, but most of them require disassembling and replacing the seal from scratch.

3. There is a Russian leak during normal homework. A small number of natural leaks in centrifugal pumps during operation are due to normal wear and tear or reaching the end of their service life, while the majority are caused by significant changes in operating conditions or improper operation and protection.

(1) Leisure, cavitation, or prolonged pressure buildup can cause damage to the seal;

(2) The practical output of the pump is relatively small, and many medium pumps circulate internally, causing heat accumulation and gasification of the medium, resulting in seal failure;

(3) Excessive reflux caused sediment to rise at the bottom of the suction tube side container (tower, kettle, tank, pool), damaging the seal;

(4) For long-term shutdowns, there was no manual turning when starting from scratch, and the sealing surface was torn due to adhesion during the conflict;

(5) An increase in corrosive, polymeric, and adhesive substances in the medium;

(6) Rapid changes in environmental temperature;

(7) Frequent changes or adjustments in working conditions;

Sudden power outage or malfunction shutdown, etc. During normal operation, natural leakage in centrifugal pumps can often become a major issue or loss if not detected in a timely manner. It is necessary to pay attention to and adopt effective measures.