1. Bypass valve: the ball valve is generally opened by static water, so the bypass valve is set for flat pressure first, that is, both sides are filled with water;
2. Air valve: when filling water, remove the air and take the float to close the valve by itself; During drainage, make up air and the pontoon will descend by itself;
3. Pressure relief valve: when opening and closing the valve, drain the pressure water between the valve and the sealing cover to avoid wearing the sealing cover;
4. Blowdown valve: discharge the sewage from the lower part of the spherical shell.
