Water Pump Mechanical Seal Overhaul Misunderstanding
1. The greater the amount of spring compression, the better the sealing effect. In fact, the amount of spring compression is too large, which can lead to sharp wear of the friction pair and instant burning; Excessive compression causes the spring to lose the ability to adjust the end face of the moving ring, resulting in seal failure.
2. The tighter the moving ring sealing ring, the better. In fact, too tight the moving ring sealing ring is harmful and harmful. First, it aggravates the wear between the sealing ring and the shaft sleeve and premature leakage; Second, it increases the resistance of axial adjustment and movement of the moving ring, and it cannot be adjusted in time when the working conditions change frequently; Third, the spring is easily damaged by excessive fatigue; The fourth is to deform the moving ring sealing ring and affect the sealing effect.
3. The tighter the static ring sealing ring, the better. The static ring sealing ring is basically at rest, and the sealing effect will be better when it is relatively tight, but too tight is also harmful. First, it causes the static ring seal to be overly deformed, which affects the sealing effect; Second, the static ring material is mostly graphite, which is generally brittle, and excessive force is easy to cause chipping; Third, it is difficult to install and disassemble, and it is easy to damage the static ring.
4. The tighter the impeller lock mother, the better. In mechanical seal leakage, leakage between the shaft sleeve and the shaft (shaft-to-shaft leakage) is relatively common. It is generally believed that inter-shaft leakage is that the impeller lock mother is not locked, in fact, there are many factors that lead to inter-shaft leakage, such as intershaft pad failure, offset, impurities in the shaft, large shape and position error between the shaft and the shaft sleeve fit, contact surface failure, clearance between various components on the shaft, and too long shaft head thread, etc. will lead to intershaft leakage. Excessive locking of the locking mother will only lead to premature failure of the intershaft pad, on the contrary, moderate locking of the locking mother, so that the intershaft pad always maintains a certain compression elasticity, in the operation of the locking mother will automatically lock in time, so that the shaft is always in a good sealing state.
5. The new one is better than the old. Relatively speaking, the effect of using the new mechanical seal is better than that of the old one, but the quality or material of the new mechanical seal is not properly selected, and the large matching size error will affect the sealing effect; In polymeric and permeable media, it is better not to replace the static ring if there is no excessive wear. Because the static ring is at rest for a long time in the static ring seat, the polymer and impurities are deposited as one, which plays a better sealing role.
6. It is better to disassemble and repair than not to dismantle at all. Once there is a leakage of the mechanical seal, it is urgent to dismantle and repair, in fact, sometimes the seal is not damaged, just adjust the working conditions or adjust the seal properly to eliminate the leakage. In this way, it not only avoids waste, but also verifies its fault judgment ability, accumulates maintenance experience, and improves the quality of maintenance.
