Baffles size restriction

Standard pipe sizes will be used for the inlet and outlet nozzles. It is important to avoid flow restrictions at the inlet and outlet nozzles to prevent excessive pressure drop and flow-induced vibration of the tubes. As well as omitting some tube rows (see Section 12.5.4), the baffle spacing is usually increased in the nozzle zone, to increase the flow area. For vapours and gases, where the inlet velocities will be high, the nozzle may be flared, or special designs used, to reduce the inlet velocities Figure 12.17a and b. The extended... 

In summary, the addition of baffles, tubes, and other obstacles restricts large-scale solids movement, reduces the gas and solids backmixing, improves the radial gas and solids mixing, and causes segregation of particles of different sizes. 

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