Ventilation cover

Breather caps GN 774.1 prevent the build up of a pressure drop over liquids in a tank. They are used when a tank has to be rapidly emptied. The elastic membrane ensures a sufficient supply of air to prevent any vacuum build-up in the tank. Besides that, the back pressure behind the membrane will prevent the escape of any liquid in the tank to the outside, especially during transport. If the tank is turned upside down with the additional back pressure from the liquid, it will be sufficient to keep the outlet firmly shut.