For a long time, the sediment wear has been a big problem which puzzles our country hydraulic machinery technical personnel and the power station personnel. Since recent 50 years, many scientific research institutes, universities and colleges, and the factory so long-term a lot of research and experiments, due to the complexity of the mechanism of abrasion damage, so far has not yet found a kind of effective countermeasures, and even can be said that without the formation of a recognized standards and norms.

For sediment laden flow and high head Francis turbine, guide of guide vanes of a body of water under the end and a top cover, a bottom ring wear plate usually occur relative to other flow components more serious abrasion. The Liujiaxia, Gongzui, Wujiangdu and hydropower station has just started running when the unit flow component wear is not serious, but a few years of operation appeared more serious sediment erosion phenomenon. Therefore, from the aspect of reducing weight, protection Water Leakage vane vane, extend the unit overhaul cycle and other requirements, hydropower installed turbine cylinder valve station is necessary. Install the cylinder valves for hydraulic turbine components and the whole unit has great comprehensive benefit.

The importance of cylindrical valve:

• The clearance cavitation and abrasion of the water guide mechanism, and the protection of the turbine flow to the;

• Reducing the leakage of the guide vane and the loss of electricity leakage, which is beneficial to the braking of the unit;

• The cylinder valve is an effective anti runaway device unit;

• Water filling time is shortened, and the operation flexibility of the unit is improved;

• The power station project investment decrease, reduce the amount of excavation and plant crane span, shorten the construction period;

• Tube valve operation is flexible and convenient, to bear the peak load of the unit, the use of cylindrical valve is more favorable;

• When an emergency is in trouble, it can quickly cut off the flow of water, stop the rotation of the turbine, and protect the generator set.