5 misunderstandings of water pumps in mechanical seal inspection

1) The larger the amount of spring compression, the better the sealing effect. In fact, if the spring compression amount is too large, the friction pair may be sharply worn and burned instantaneously; 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 seal is, the better the sealing effect. In fact, the dynamic ring seal is too tight and harmful. First, the wear between the seal ring and the bushing is intensified, and the leakage is premature; secondly, the resistance of the moving ring in the axial adjustment and movement is increased, and the adjustment cannot be made timely when the working conditions change frequently; the third is that the spring is excessively fatigued and easily damaged; fourth, deform the moving ring seal and affect the sealing effect.

3 ) The tighter the static ring seal is, the better the sealing effect. The static ring seal is basically in a static state, and the relatively tight sealing effect will be better, but too tight is also harmful. First, it causes the static ring seal to deform excessively, which affects the sealing effect. Second, if the static ring is made of graphite, it is generally brittle and easily cracked due to excessive stress. Third, the installation and disassembly are difficult and the static ring is easily damaged.

4 ) The more tightly the impeller lock nut is, the better the sealing effect. In mechanical seal leakage, leakage between shaft sleeve and shaft ( leakage between shafts ) is common. It is generally believed that the leakage between shafts means that the impeller lock nut is not locked. In fact, there are many factors leading to the leakage between shafts, such as the failure of the pads between shafts, offset, impurities in the shafts, large form and position errors in the joint between the shafts and the shaft sleeves, damaged contact surfaces, gaps between various parts on the shafts, overlong thread of the shaft heads, and so on, will all lead to the leakage between the shafts. Excessive locking of the lock nut will only lead to premature failure of the inter-axle pad. On the contrary, proper locking of the lock nut will keep the inter-axle pad in a certain compression elasticity all the time, and the lock nut will lock automatically and timely during operation so that the inter-axle pad will always be in a good sealing state.

5) The new one is better than the old one. Relatively speaking, the effect of using a new mechanical seal is better than that of the old one, but the quality or material selection of the new mechanical seal is not appropriate. The large dimensional error will affect the sealing effect; in the polymerizable and permeable medium, if there is no excessive wear on the static ring, no need to replace it. Because the static ring is in a static state for a long time in the static ring seat, the polymer and impurities are deposited as one body, which has a good sealing effect.