Automatic Air Vent Valve Screwed End Features : - The Automatic Air Vent Valve has a single automatic float and carries out two main functions: the evacuation fo consistent air flow through a pipe line (e.g. during loading pressurization of the plant) and degassing. Which discharges air trapped or formed in the pipeline, while functioning. This valve has a paramount importance in climatisation networks and systems, evacuating and discharging trapped air in water pips for servies under pressure.