Centrifugal fan
First Claim
1. A centrifugal fan comprising:
- a scroll casing that has first and second flat base walls, a circumferential side wall covering the circumferences of said base walls, an air inlet that is opened in an axial direction being formed on a center portion of said first base wall and an exhaust port that is opened in a circumferential direction being formed on one portion of said circumferential side wall;
a motor that is attached to a center portion of said second base wall at the inside of said casing so that a rotating shaft of the motor is perpendicular to said second base wall;
an impeller that is fixed to said rotating shaft, the impeller having many blades along the outer region thereof; and
a backflow prevention mechanism that prevents backflow from said exhaust port during fan halting by shutting an airflow path to said exhaust port, wherein said backflow prevention mechanism has a flat-shaped flap that is rotatably supported by said first base wall so that one side touching to said first base wall is a rotation axis, and the rotation axis is inclined with respect to the vertical direction so that the flap shuts the airflow path under its own weight in a horizontal-use position where the rotating shaft of said motor is horizontal.
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Accused Products
Abstract
A centrifugal fan includes a scroll casing consisting of first and second flat base walls, a circumferential side wall. An air inlet is formed on the first base wall, an exhaust port is formed on the side wall. A backflow prevention mechanism is arranged in the airflow path to prevent backflow from the exhaust port during fan halting. The mechanism has a flap that is rotatably supported by the first base wall and its rotation axis is inclined with respect to the vertical direction so that the flap shuts the airflow path under its own weight in a horizontal-use position where the rotating shaft of the motor is horizontal. The flap is inserted into a slit from the outside and is held by a stopper plate. A protrusion, which contacts with the rim of the flap when the flap shuts the airflow path, is formed inside the walls.
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Citations
9 Claims
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1. A centrifugal fan comprising:
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a scroll casing that has first and second flat base walls, a circumferential side wall covering the circumferences of said base walls, an air inlet that is opened in an axial direction being formed on a center portion of said first base wall and an exhaust port that is opened in a circumferential direction being formed on one portion of said circumferential side wall;
a motor that is attached to a center portion of said second base wall at the inside of said casing so that a rotating shaft of the motor is perpendicular to said second base wall;
an impeller that is fixed to said rotating shaft, the impeller having many blades along the outer region thereof; and
a backflow prevention mechanism that prevents backflow from said exhaust port during fan halting by shutting an airflow path to said exhaust port, wherein said backflow prevention mechanism has a flat-shaped flap that is rotatably supported by said first base wall so that one side touching to said first base wall is a rotation axis, and the rotation axis is inclined with respect to the vertical direction so that the flap shuts the airflow path under its own weight in a horizontal-use position where the rotating shaft of said motor is horizontal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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Specification