HYDRAULIC FEATURES This automatic air vent valve is a single float valve designed for solar thermal energy plants, and carries out two main functions: the evacuation of a consistent air flow through the system (e.g. during loading/pressurization of the plant), and degassing which discharges air trapped in the pipeline, while functioning, in particular in the solar collectors. This valve has a paramount importance in solar thermal energy plants, evacuating and discharging trapped air in the pipelines and in the solar collectors. As a matter of fact, the presence of oxygen in the system can provoke numerous negative phenomena such as anodic corrosion, localized noise, air pockets, obstructions, etc., which may significantly compromise the performance and integrity of the systems. These valves are usually installed at the summit of the primary circuit in a solar thermal energy plant, and are resistant to the high temperatures that the heat-transfer fluids can reach, even in stagnation phases.