Multiple blade window fan

A portable window fan comprising:

• housing means comprising a bottom wall for mounting on a sill of a window with an open sash, a top wall for engaging the open sash, a rear wall defining a plurality of inlet openings, and a front wall defining three discharge regions substantially aligned with said inlet openings and spaced apart in a given direction substantially parallel to said top wall;
• three fan blades mounted within said housing means, each fan blade arranged to produce air flow through a different one of said discharge regions;
• electrical drive means coupled to said fan blades and operative to induce rotation thereof, said electrical drive means comprising an electric motor operatively coupled to each said fan blade;
• grill means covering said discharge regions;
• and
• control circuit means including switch means for connecting said electric motors to a source of electrical energy, said switch means being selectively activatable into first, second and third operating conditions;
• said first operating condition providing energization of only one of said electric motors, said second operating condition providing energization of only two of said electric motors, and said third operating condition providing energization of all three said electric motors.