Tank vent check valves are used on all ships, in order to ventilate tanks onboard, such as ballast tanks, fresh water tanks, lube oil tanks and fuel tanks. According to the international loadline convention from 1966, all tanks aboard ships are to be protected from penetration of seawater. In our range of tank vent check valves we also offer a valve for ventilating liquid mud tanks, to prevent mud from entering the valve head. A swing check valve on the side of the valves allows for draining of the mud in case of overfilling. It is optional to order the tank vent check valves with flame, bug or rat screens. A flame screen will prevent burning or glowing particles to enter the tank while a bug or rat screen will prevent ingress of bugs, rats or other pests from the tanks.