Sea valves are generally also known as submarine valves, because they are mostly installed on the bottom of the warship below the no-load waterline, or on both sides of the warship, or on the curved part of the hull connecting the bottom and the side of the ship. The sea valve is generally used to open or close the Dalian marine valve through the transmission mechanism on the deck of the warship, so as to control the seawater entering the warship, so as to ensure that there is enough water on the warship to cool the machine and clean the warship.

On naval warships, the main engine and auxiliary engine used for a long time are mostly large steam turbines and diesel engines. These machines will generate a lot of heat when they work. Most of these heat is used as power to maintain the operation of the warship, and some of the excess heat needs to be cooled by cooling services to avoid damage to the warship.