Negative pressure type range hood

The utility model discloses a negative pressure type range hood which consists of a negative pressure chamber, an air knife, a turbo charger fan, an air filtering net, a fume collecting chamber, an induction unit and a check valve, in the specification, A represents inlet air, B represents cooking fume, and C represents high speed air flow (50m/s); the section of the air knife is trapezoid-shaped; the air inlet of the air knife is in threaded connection with the outlet of the turbo charger fan; the outlet of the air knife is a square which is 38 and 116 in width and length; the section of the induction unit is of a U-shaped structure and an angle of 35-38 degrees is formed between the induction unit and the horizontal plane. The range hood has the beneficial effects that the structure of a conventional range hood is fundamentally changed, a fan impeller and an oil net which are essential in the conventional range hood are omitted in the channel from which the cooking fume is sucked out, and thus the difficulty that the range hood is hard to clean is fundamentally solved; the resistance in discharging the cooling fume is reduced, the working efficiency of the range hood is improved, and the environment pollution caused by detergent is also reduced.