CENTRIFUGAL FAN Russian patent published in 2011 - IPC F04D17/08 

FIELD: engines and pumps.

SUBSTANCE: centrifugal fan includes housing, impeller with carrying and cover discs, which is installed in it; between the discs there fixed are profile blades each of which has in the area of exit edge an open annular cavity formed with cylindrical shell on the side of working surface of the blade, interconnected through conical holes in carrying and cover discs with small-channel units located on their outer side and having confuser channels which are tangential in relation to the hole; at that, elastic non-closed annular plate is fixed in cantilever manner and equally spaced with a gap in relation to cylindrical shell of annular cavity on carrying and cover discs.

EFFECT: aerodynamic isolation of excavation from worked-out space at combined ventilation of coal mines.

3 dwg