In the chemical pump mechanical seal repair several misunderstandings 1) The greater the amount of spring compression, the seal effect may not be better. Some people mistakenly believe that the greater the spring compression, the better the sealing effect. In actual fact, the spring compression is too large, can lead to rapid wear and tear friction, burned instantly; excessive compression of the spring to lose the ability to adjust the dynamic ring end face, leading to seal failure. 2) moving ring seal is not as tight as possible. In fact, the ring is too tight moving ring harmless, one is to aggravate the wear and tear between the ring and the sleeve, premature leakage; the second is to increase the axial movement of the ring, the resistance of the movement, frequent changes in the conditions can not be adjusted timely ; Third, excessive fatigue damage to the spring; Fourth, the ring deformation ring, affecting the sealing effect. 3) Static ring seal is not as tight as possible. Static ring seal is basically static state, the relatively tight seal effect will be better, but too tight is also harmful. First, excessive deformation caused by static ring seal, affecting the sealing effect; Second, static graphite material to the majority, generally more brittle, excessive stress can easily cause fragmentation; Third, the installation and removal difficulties, can easily damage the static ring. 4) Impeller lock mother is not as tight as possible. Leakage between shaft sleeve and shaft (shaft leakage) is more common in mechanical seal leakage. Generally believed that the leakage between the shaft impeller lock is not locked, in fact, lead to leakage between the shaft more, such as shaft washers failure, offset, there are impurities in the shaft end face, shaft and sleeve with a larger Department Shaped position error, contact surface damage, there is a gap between the various components on the shaft and the shaft thread is too long and so will lead to shaft leakage. 5) Disassembly is better than not dismantled. In the event of a mechanical seal leak eager to overhaul, in fact, sometimes the mechanical seal is not damaged, just adjust the condition or adjust the seal to eliminate leakage. This avoids waste.