Nozzles are used in liquid/solid or gas/solid separation. The wedge wire screen design of each nozzle and the exact quantity will be proposed in order to obtain a perfect distribution or collection of flow thus almost eliminating the channeling, wall effects or dead zones. Common applications include under drain media retention elements or flow distributors in demineralizers and water softeners in pressure and gravity sand filters. Nozzles can also be used as collectors at the bottom of the vessels by installing a number of nozzles uniformly across a tray plate. The combination of high open area and a non-plugging slot design makes this nozzle/collector application popular.