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Outer basket is an outer slit screen in radial flow reactors. It is located along the inner vessel surface. They are usually installed inside vertical reactors and distribute or collect the flow. The outer surface of the basket contacts the catalyst and is usually made of triangular wire. It can be used to move the flow towards the center or outwards the center. Outer baskets consist of segments assembled by fasteners. The space between the baskets and the central pipe in the upper part is closed with a blind plate. The flow area of the baskets is calculated to ensure stable operation in a wide range of flow rates. Cord or ceramic fiber gaskets are used to seal the gaps and ensure tightness. Basket’s design features are determined according to the given loads from the catalyst layer and the pressure drop.

Design parameters

  • Working and design pressure and temperature
  • Flow parameters
  • Physical characteristics of the working environment
  • Pressure drop
  • Packing parameters
  • Dimensions of the reactor and top hatch

Design parameters

  • Strict control of verticality, straightness and torsion tolerances at factory
  • Dismountable structure allows mounting through the reactor hatch
  • Large screen area, minimal hydraulic resistance
  • Rigid design withstands packing weight and pressure drop
  • The usage of a slit screen stops catalyst leakage and excludes clogging of slots due to the usage of triangular wire


  • Platforming
  • Reforming
  • Ammonia synthesis


Pictures: annular clearance between central pipe and basket; CCR reforming basket; styrene monomer basket; outer basket model; flow direction; basket flow direction variations.