What Is a Master Valve?

The main valve generally refers to the hydraulic control valve. It is an important equipment on the water diversion system of the hydropower station. The main technical requirements for the structure and performance of the main valve are: the main valve should have a simple structure, small dimensions, light weight, reliable work, and easy operation. , Good water resistance. In addition, the pressure capacity of the main valve should be able to meet the maximum water hammer pressure value of the power station.

Main valve in some

Butterfly valve

Butterfly valves are also called butterfly valves. Butterfly valves are widely used in power stations with heads below 200m. According to the valve spindle device type, the butterfly valve is divided into vertical axis butterfly valve (the valve axis is arranged vertically) and horizontal axis butterfly valve (the valve axis is arranged horizontally). It has the characteristics of small size, simple structure, low cost, convenient operation, large water leakage, and the tendency to close by itself.

Main valve ball valve

Ball valves are used in power stations with heads above 250m. The ball valve has the characteristics of small water flow resistance when fully opened, good sealing performance when fully closed, small leakage, large size, complicated structure and high cost.

Main valve quick gate

For a hydropower station with a longer diversion pipeline and a surge tank, a quick gate is installed on the upstream pipeline of the surge well; for a hydropower station with a short diversion pipeline and no surge tank, the quick gate is installed at the water intake of the pipeline.

Main spool valve

For hydropower stations with high sediment and high heads and large amplitude changes, cylinder valves are often installed. When the cartridge valve is closed, the valve body forms a closed ring between the fixed guide vane and the movable guide vane, preventing water flow from passing through. When the cartridge valve is opened, the entire valve body is retracted into the turbine support ring and the top cover, which does not interfere with the water flow. The valve body opens and closes in a linear motion up and down, with less operating force and lower installation accuracy requirements. Its main advantages are:

1. The cartridge valve is installed between the fixed guide vane and the movable guide vane. Compared with the ball valve and butterfly valve installed in front of the volute, the longitudinal length of the entire plant is shortened and the engineering cost is reduced.

2. It has better sealing performance, which can effectively prevent the abrasion of the guide vane due to water leakage.

3. The opening and closing time is short, which can better adapt to the power system's requirements for fast startup of hydropower stations, and can effectively prevent the unit from overspeeding in the event of an accident.

4. It can eliminate the additional hydraulic loss of the shrinkage and expansion section expansion joints at the valve inlet and outlet of the machine.

5. The cylinder valve opens and closes in a linear motion. When closing, the closing speed can be adjusted according to the water pressure rising rate. ^[2]