The invention relates to an improvement in nozzles/screen for fluid flow distribution/collection used In fluid flow distribution/collection used In fluid processing units. Improvement in conventions nozzle/screen comprises a flow restricting cylindrical body to have ring washer shape aperture control at inlet/outlet. The improved nozzle/screen comprises outer casing made of stacked flat rings with micro opening between said stacked ring providing uniform throughout its periphery. A central conduit having holes for flow of fluid entering through the said outer casing. The said conduit having means to regulate fluid flow.