The design and application range of the drain valve covers the pipeline system with the medium of fuel oil, lubricating oil, fresh water and seawater. This type of self-sealing drain valve can play a key role in piping systems, especially in the case of controlling the drain of liquid or gas media. Its self-closing function ensures that under certain pressure or specific conditions, the valve can be automatically closed, thereby preventing the medium from continuing to flow or leak, and ensuring the safe and stable operation of the system.