CENTRIFUGAL AIR BLOWER

摘要

There is provided a centrifugal air blower capable of effectively suppressing noise caused by the shapes of a tongue part and a bell mouth formed in a scroll casing.;The centrifugal air blower includes: a fan 3 composed of a bottom plate 6 fixed to a rotating shaft, multiple blades 8 whose bases are fixed to the outer circumference of the bottom plate, and an annular rim 9 provided concentrically with the bottom plate to couple distal ends of the blades; a scroll casing 4 for housing the fan and having a suction port 11 on one end side in an axial direction of the rotating shaft; a spiral flow passage 19 formed around the fan in the scroll casing; and a tongue part 16 for suppressing an inflow of air from the end of winding to the beginning of winding of the spiral flow passage. A portion of the tongue part on the other end side in the axial direction of the rotating shaft is inclined to increase a dimension of overhanging in a counter-rotating direction of the fan toward the other end side in the axial direction of the rotating shaft.

主权项

1. A centrifugal air blower characterized by comprising:
a fan composed of a bottom plate fixed to a rotating shaft, a plurality of blades whose bases are fixed to an outer circumference of the bottom plate, and an annular rim provided concentrically with the bottom plate to couple distal ends of the blades; a scroll casing for housing the fan and having a suction port on one end side in an axial direction of the rotating shaft; a spiral flow passage formed around the fan in the scroll casing; and a tongue part for suppressing an inflow of air from end of winding to beginning of winding of the spiral flow passage, wherein a portion of the tongue part on the other end side in the axial direction of the rotating shaft is inclined to increase a dimension of overhanging in a counter-rotating direction of the fan toward the other end side in the axial direction of the rotating shaft.