Portable fume exhaust fan apparatus

Claim 1

A PORTABLE FUME EXHAUST FAN APPARATUS COMPRISING, IN COMBINATION, AN EXHAUST CONDUIT ADAPTED TO BE SUPPORTED ON A WINDOW SILL BENEATH A WINDOW SECTION, DAMPER MEANS IN SAID CONDUIT, A FLEXIBLE CONDUIT CONNECTED AT ONE END IN AIR TIGHT RELATION TO SAID FIRST MENTIONED CONDUIT, A FLANGED COUPLING ON THE OTHER END OF SAID FLEXIBLE CONDUIT, A FAN HEAD INCLUDING A CYLINDRICAL PORTION HAVING A FLANGE AT ONE END AND A TAPERED OUTLET PORTION HAVING A FLANGE AT EACH END, THE FLANGE AT THE SMALLER END BEING BOLTED TO THE FLANGED COUPLING OF SAID FLEXIBLE CONDUIT AND THE FLANGE AT THE OTHER END BEING BOLTED TO THE FLANGE OF SAID CYLINDRICAL PORTION, THE OTHER END OF SAID CYLINDRICAL PORTION BEING FORMED WITH AN OPEN FUME INTAKE, TRANSVERSE SHELVES EXTENDING ACROSS SAID CYLINDRICAL PORTION, A PAIR OF BLADED EXHAUST FANS MOUNTED ON SAID SHELVES, A PAIR OF ELECTRIC MOTORS INDIVIDUALLY CONNECTED TO SAID EXHAUST FANS, AN INDIVIDUAL WIRE CONNECTED TO EACH ELECTRIC MOTOR, A CONTROL BLOCK HAVING AN INDIVIDUAL SWITCH FOR EACH WIRE, A COMMON WIRE EXTENDING TO SAID CONTROL BLOCK FROM A SOURCE OF ELECTRIC POWER, A CLAMP RING ASSEMBLY FOR SAID CYLINDRICAL PORTION, SAID CLAMP RING ASSEMBLY COMPRISING A PAIR OF LATERALLY-SPACED SPLIT CLAMP RINGS HAVING CLAMPING EARS AND BOLTS, A BALANCE PIECE EXTENDING BETWEEN SAID BOLTS, SAID BALANCE PIECE HAVING A SERIES OF ADJUSTING HOLES THEREIN, A PIVOT BOLT SELECTIVELY ENGAGEABLE IN ONE OF SAID ADJUSTING HOLES FORR SUPPORTING SAID FAN HEAD, AND VERTICALLY ADJUSTABLE MEANS SUPPORTING SAID PIVOT BOLT SELECTIVELY TO VARY THE HEIGHT OF SAID FAN HEAD.