1. Poor quality of mechanical seal device piping welding, the serious influence the safety of the feed water pump, liquid feed water pump mechanical seal design temperature is 80 ℃ alarm, 90 ℃ jump pump.When in the operation of the piping slight leakage slow temperature increase the mechanical seal liquid (due to the heat exchanger of the mechanical seal liquid is reduced, or that there is no good mechanical seal liquid cooling), when piping serious leak the mechanical seal liquid temperature rise sharply.All of these make the mechanical seals ring and static ring and stick and get very good cooling, make the dynamic and static ring overheating and damage.Repeated in the operation of the feed water pump tripping due to mechanical seal piping leakage, also increased the wear and tear of mechanical seal.So for mechanical seal device piping welding quality put forward higher requirements.
2. The influence of the feed water quality of mechanical seal.Due to mechanical sealing device for water quality request is higher, when the water quality deterioration, due to mechanical sealing device of circulation piping is thinner, reduce mechanical seal device easy blockage caused by mechanical seal liquid temperature;When feed water pump in low speed running, when the water quality deterioration, due to the ascension of reverse spiral groove pressure is low, the impurity cannot be taken away by water in a timely manner, lead to the sediment in the mechanical seal affixed with noodles, cut mechanical seal ring of the stick and activity, make the mechanical seal leakage.Therefore we must strengthen unit start-up downtime and normal operation of the supervision of the water quality.
3. The influence of the operation mode of mechanical sealing device.
A. When the unit is in constant load adjustment, make the feed water pump is in working condition or feed water pump are in a state of start-stop, often leads to the instantaneous motion, the feed water pump pump shaft stick and clearance between the feed water pump of dynamic and static ring is too small, not enough to form liquid film, and cause of dynamic and static ring of dry friction, make the damage of mechanical seal device.Feed water pump appeared due to destruction of the balance of pump group itself, the thrust bearing wear, lead to machinery seal leakage.So in the running to minimize the base of pump group.Prevent damage of mechanical seal device.
B. When the normal standby of the feed water pump, the pump still at this time.Due to the standby must be put into warm pump device, at this time although in the mechanical seal device of the cooling water, but as a result of not rotating pump group, so the water can't flow in mechanical seal, mechanical seal of the graphite ring (static ring) in the high temperature of 100 ℃ above, and when the standby pump and immediate loading, above 100 ℃ after cooler water flowing suddenly turned into more than 30 ℃ water flows through mechanical seal device of graphite ring, make graphite rings quenching and cracks, cause mechanical seal leakage.So when the normal standby pump group can add a small circulation pump mechanical seal device of flowing water, avoid the occurrence of the above phenomenon.