| CPC F04D 29/164 (2013.01) [F04D 29/547 (2013.01); F05D 2250/51 (2013.01)] | 10 Claims |
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1. A fan comprising:
an impeller including a boss and a plurality of blades, the boss having a columnar shape and being driven to rotate by a motor, the plurality of blades being provided radially from the boss;
an air guide portion across which an airflow moves from an upstream end to a downstream end of the air guide portion, the air guide portion having a cylindrical shape and being provided to cover an outer peripheral end of each of the plurality of blades; and
a bell mouth having an annular shape, the bell mouth being provided to extend to a position that is upstream from the upstream end of the air guide portion from a position that is downstream from the upstream end of the air guide portion and that is upstream from the impeller, the bell mouth including an upstream end point and a downstream end point defining a first suction passage inside the bell mouth and defining, together with an inner surface of the air guide portion, a second suction passage outside the bell mouth, wherein the second suction passage extends uninterruptedly between the upstream end of the air guide portion and the downstream end point of the bell mouth portion;
between the upstream end point located in an inlet of the first suction passage and the downstream end point located in an outlet of the first suction passage of the bell mouth, the bell mouth including a minimum possible radius point to which a distance, in a radial direction, from a rotation axis of the boss is smaller than a distance, in the radial direction, from the rotation axis to the downstream end point.
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10. A fan comprising:
an impeller including a boss and a plurality of blades, the boss having a columnar shape and being driven to rotate by a motor, the plurality of blades being provided radially from the boss;
an air guide portion across which an airflow moves from one end to an other end of the air guide portion, the air guide portion having a cylindrical shape and being provided to cover an outer peripheral end of each of the plurality of blades; and
a bell mouth having an annular shape, the bell mouth being provided to extend to a position that is upstream from the one end of the air guide portion from a position that is downstream from the one end of the air guide portion and that is upstream from the impeller, the bell mouth defining a first suction passage inside the bell mouth and defining, together with an inner surface of the air guide portion, a second suction passage outside the bell mouth,
between an upstream end point located in an inlet of the first suction passage and a downstream end point located in an outlet of the first suction passage of the bell mouth, the bell mouth including a minimum possible radius point to which a distance, in a radial direction, from a rotation axis of the boss is smaller than a distance, in the radial direction, from the rotation axis to the downstream end point;
a plurality of ribs each of which is formed in the shape of a plate, the plurality of ribs being provided in the second suction passage, the plurality of ribs connecting the bell mouth and the air guide portion, the plurality of ribs being arranged in a circumferential direction,
wherein the plurality of ribs are inclined to an axial direction of the rotation axis and serve to change a direction of air to pass through the second suction passage.
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