Scrolling reversal

The centrifugal fan has an inlet on the axis of rotation and outlet from a scroll casing 90° from the inlet. The centrifugal fan is not reversible. The characteristics of the fan are determined by blade shape, i.e. ... 

The Sorticanter has a scroll with reversing pitch on one side, which skims a floating solids layer off the top of the carrier hquid, usually an aqueous brine of intermediate density. Sinking solids are scrolled out similarly to normal decanter centrifuges, and liquid is discharged under pressure via a stationary but variable impeller. The Sorticanter is utihzed in the plastics recycling industry. 

A further consideration in the shape of the continuous scroll was that as material transferred along its length, it was likely to increase in temperature and reduce in viscosity. Therefore to maintain a constant flow rate across this scroll, its width was increased as the distanee from the end of the rotor increased (Figure 16). The actual tangential shaped part of this scroll can be set at a reverse angle, both to increase shear and to assist in protection of the mixer dust stops. 

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