(1) Small pump seal failure below 715kW often produce grinding shaft, grinding shaft position mainly in the following: dynamic ring auxiliary seal, static ring position, a few springs have grinding axis phenomenon.

(2) The main reasons of grinding: ① BIA-type double-ended mechanical seal, back pressure state is a bad working condition, the media particles, impurities are easy to enter the sealing surface, so that the seal failure. ② The main part of the grinding shaft is rubber bellows, and because the upper sealing surface is in bad lubrication state, the friction torque between the static and dynamic ring is larger than the transmission torque between the rubber bellows and the shaft, and the relative rotation occurs. ③ Dynamic and static ring auxiliary seal due to the sewage in the weak acid, weak alkali corrosion, rubber pieces have been inelastic. Some have rotten, lost the proper function, resulting in the phenomenon of grinding shaft.

(3) To solve the above problems, now take the following measures: ① to ensure that the lower end of the cover, the cleanliness of the oil chamber, not clean the oil prohibited assembly. ② machine oil chamber oil tank line should be higher than the static and dynamic ring sealing surface. ③ according to the use of different media use different structure of the machine seal. For high-lift pump should be re-designed mechanical seal structure, the corrosive media rubber should be selected weak acid, weak alkali of fluorine rubber. Seal ring should be added to the ring.

Pumps are widely used in power, chemical, metallurgy, petroleum, agriculture and other sectors of the national economy, is the energy onsumption of large, annual power consumption of the pump accounts for about 1/5 of the total power generation. Therefore, it is very important to improve the safety and economy of the pumps in various production systems. Rapid diagnosis of pump failure, reasonable maintenance of equipment, and constantly improve the operation of the pump in the system effect is engaged in pump equipment design, installation and maintenance of engineering and technical personnel common goal.
In recent years, there are some weak links in the field of pump maintenance, the quality of work and work efficiency are inadequate, the main reason is that a large number of mechanical engineering graduates in the years after graduation, the work is done and maintenance, And engineering students in the school almost no maintenance of equipment in the field of formal training; industrial production in the actual repair business, more by the experienced but no academic engineers or workers to deal with these people also lack the basic training of various basic training , So can not carry out a high level of maintenance work; pump maintenance project managers have received high engineering education, generally only from the instructions to engage in repair, and equipment designers generally lack the use of experience, but also from the user feedback is less, So the development of the pump maintenance instructions are not necessarily reasonable.

Mainly have the following ends: electric rotor unfair balance; coupling joint is not good; bearing wear buckling; rotating part of the loose parts, cracks; pipe support is not strong and so on. Do not take the debugging, repair, reinforcement, straightening, change and other methods of disposal. The above-mentioned things are the common cause of the failure of the pump, not all reasons, the practice of dealing with failure, due to actual analysis, should follow the principle of the first outside.