Inlet Box Scroll
The scroll of a fan inlet box laid flat: its straight sides and arc unrolled, each line across as deep as the box is there. The scroll of a fan inlet box laid flat: the plate round the bottom of the box, its straight sides and arc unrolled, as deep at every line across it as the box is there, for a box deeper at the top than at the bottom.
How the inlet box scroll is developed, with a worked example · Hoods, plenums and cyclones