Fold by function
1. Bypass valve: The ball valve is generally opened in still water, so the bypass valve is set to be flat pressure first, that is, the two sides are filled with water;
2. Air valve: when water is filled, the buoy is used to close the valve when the air is removed; when draining, the buoy is used for supplementary air, and the buoy goes down by itself;
3. Pressure relief valve: When opening and closing the valve, remove the pressure water between the valve and the sealing cover, so as not to wear the sealing cover;
4. Sewage valve: discharge the sewage in the lower part of the spherical shell.

Folding press transmission
1. Pneumatic ball valve
2. Electric ball valve
3. Hydraulic ball valve
4. Gas-hydraulic ball valve
5. Electro-hydraulic ball valve
6. Turbine drive ball valve