Baffle

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Baffles (also baffles) are components that protrude into the stirred tank and prevent the entire stirred contents of the tank from rotating with the stirrer due to the inertia of the medium. They are used in the technical mixing of substances.

function

Flow baffles are flow-breaking fixtures in stirred tanks. They prevent the fluid moved by the centric agitator from rotating in the stirred tank.

They are installed on the tank wall or, in the case of enamelled stirred tanks , through a nozzle on the upper floor of the apparatus.

In the case of low- viscosity liquids, they enable thorough mixing. However, the baffle is not useful for media with a higher viscosity, but leads to flow shadows and imperfect mixing.

Designs

  • In non-coated agitators (e.g. stainless steel ones), baffles are connected to the container wall and essentially consist of flat iron welded or screwed to the container wall. In the optimal case, four such flat irons are attached to the container wall at an angle of 90 ° to each other. The width of such a baffle is approximately 0.1 to 0.12 × the container diameter.
  • There are different designs of baffles in enamelled apparatus, which essentially always correspond to a profiled, tubular component. The profile of the pipe (cross section) depends on the installation situation or manufacturer-specific:
    • Cylindrical baffle: The tube profile corresponds to a circle. This design is only used if there are built-in components inside the baffle which require a correspondingly large amount of space.
    • Paddle baffle: The pipe profile corresponds to an oval in cross section.
    • C-baffle from Pfaudler Werke : The profile of the built-in part corresponds to the shape of a "C", with the concave side of the C being flown against
    • Delta baffle from Thaletec (EHW Thale): The profile of the built-in part corresponds to an isosceles triangle, whereby the "pointed" or the "flat" side of the baffle can alternatively be oriented in the direction of flow.
  • Examples of different baffles

  • View into a stirred tank with a baffle attached to the tank wall

  • Enamelled paddle baffle for enamelled stirred tanks

  • Enamelled stirred tank with 3-stage stirrer and baffle (tubular installation part shown in section on the right)

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