Fixed Valves are formed from the tray panel. They are a combination of a sieve hole and a caged valve. the entrainment values of a fixed valve tray are better than on sieve trays, because the gas is entering the liquid almost horizontal. Because the downstream leg of the fied valve is smaller than the upstream leg, the liquid is pushed towards the outlet weir by the entering gas. So the capacity of the tray is better than a classical tray.