秦山核电厂3#、4#机组净凝结水泵机械密封失效分析及处理

Analysis and Processing of Failure of ATE Pump Mechanical Seal for Qinshan NPP 3#, 4# Units

对秦山核电厂3#、4#机组净凝结水泵自身结构进行分析,对其机械密封运行参数与设计标准进行对比,对密封端面线速度、密封端面比压过大、辅助冲洗水的流量、辅助冲洗水压力不足等4个可能导致密封失效的因素进行理论分析。结果表明,机械密封的密封端面比压过大是导致机械密封烧毁的根本原因。据此重新选择了集装式、平衡型的cartex-sn28/110-00机械密封替代散装式、非平衡型的M74N4/110-G6机械密封,彻底消除了净凝结水泵的机械密封频繁烧毁故障。

The structural of the ATE pump for Qinshan NPP 3# and 4# Units is analyzed, and the operation parameters and the design criteria of the mechanical seal is contrasted. Four factors that may lead to the seal failure which refer to too large seal face line speed and pressure and insufficient auxiliary flushing water flow and pressure are theoretically analyzed. It shows that the too large seal face pressure of the mechanical seal is the root cause which causes the mechanical seal burned. According to the conclusion, a set of re-mounted, balanced cartex-sn28/110-00 mechanical seal replaces the bulk-type and unbalanced mechanical seal M74N4/110-G6, which completely eliminates the frequently burned mechanical seal of the ATE pump.