Abstract: The invention relates to a system for externally holding a catalyst bed in a radial flow catalytic reactor, comprising a plurality of hollow longitudinal duct elements (2) regularly distributed in a peripheral ring around a central space (3) containing the catalyst bed and having a front filtering wall (5) facing the catalyst for the radial intake of a fluid to be treated in the catalyst bed (3). Each of the duct elements (2) is laterally defined by two lateral walls (6) radially oriented in the reactor (1) and comprising an assembling means for assembly with the respectively adjacent elements (2?) of the male member in female member (7, 8) type.

Abstract: The invention concerns a bore screen comprising a plurality of perforated rigid tubular modules (1) impermeably connected in series by ball joint means (2), allowing an extracted fluid to flow though all of the elements in series and allowing the consecutive elements to move freely relative to one another, tilting in all directions.