Modification of main shaft seal in high-head and large-capacity pumped-storage power unit;

The main shaft seal of pump turbines with large capacity at high rotational speed is more liable to failure as compared with that of conventional pump turbines.

In this paper,the advantages for construction of thrust bearings,turbine guide bearings,main shaft seal,runner seal are analyzed.

Since such-and-such problem is in existence several kinds of main shaft sealing of water-turbine,a new type seal form using for francis turbine and pump-turbine is introduced,its working principle,structural feature and points for attention are introduced.

It will be harmful to the unit for the big leakage from the main shaft sealing.

We use the itself-supply-type shaft seal in 5~# and 6~# unit of Wanjiazhai hydroelectric power station, this shaft seal is compact, scientific, wearable and we repair it very conveniently.

Based on the structure and material feature of the shaft seal for the pumped storage sets,the method and principle applied new materials on shaft seal were provided.

In this paper,the shaft seal burning loss during commissioning in Suzhi hydraulic power station was introduced,and the accident of the basic reasons particularly from shaft seal structure as well as load-bearing rack down-warping and so on were analyzed.

In the course of digging,a main bearing seal at the cutterhead of AVN3080 water leak type shield construction machine made in Germany was damaged.