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This device is a central slotted screen in radial flow reactors. It’s outer surface contacts the catalyst layer and is made as a slit screen of triangular wire. This device holds the packing and directs the flow towards the outlet. There are versions for flow going towards the center or outwards the center. The central pipe is installed in the reactor on support elements above the outlet fitting. The flow area of the outer surface of the pipe is calculated to ensure operation within the wide range of flow rates.

Necessary design parameters

  • Working and design pressure and temperature
  • Flow parameters
  • Physical characteristics of the working environment
  • Pressure drop
  • Catalyst and packing parameters
  • Dimensions of the reactor, it’s bottom, outlet fitting and top hatch

Design features

  • Dismountable structure allows mounting through the reactor hatch
  • Large screen area, minimal hydraulic resistance
  • The usage of a slit screen stops catalyst leakage and excludes clogging of slots due to the usage of triangular wire
  • Strict control of verticality and straightness tolerances


  • Platforming
  • Reforming
  • Ammonia synthesis


Pictures: 1 – UOP regeneration basket; 2 – center pipe and scallops inside a reactor; 3 – mechanical load on a center pipe; 4 – CCR line scheme; 5 – center pipe model; 6 – flow directions.