Johnson screen nozzles:
Johnson Screens nozzles are typically used in media retention vessels where specific flow and backwash rates are desired. Our applications engineers can recommend the number of nozzles needed for effective collection and distribution.
Down-flow reactors can place extremely high loading on the media retention screens at the bottom of the vessel. In some cases, this can require a false bottom to carry the load. Obviously, some provision must be made for the process flow to pass through this plate. This can most easily and effectively be done by installing a number of screen nozzles uniformly across the plate.
Johnson Screens nozzles are an ideal choice based on their combination of high strength, high open area and nonplugging slot design. Standard nozzles are 2 in. / 51 mm diameter and can be attached to the plate either with threaded end fittings or with "L" bolts. Slot openings typically range between 0.006 in. / 0.15 mm and 0.020 in. / 0.50 mm wide. They are of the unique plug-resistant Vee-Wire design, allowing particles to make only two-point contact with the edges of the wire.
In other designs such as wire mesh, particles can readily become entrapped in the mesh causing plugging and creating a continuing maintenance problem. Johnson Screens nozzles are most commonly made with 316L stainless steel. Other custom nozzles can be designed to suit special process and installation requirements.