Hair dryer
A hair dryer ( 1 ) comprises a housing ( 2 ) having a substantially cylindrical air tunnel ( 3 ), a fan ( 6 ) provided in the air tunnel ( 3 ), a motor ( 7 ) for revolving the fan ( 6 ), and a heater ( 5 ). The fan ( 6 ) is a centrifugal fan having a revolution shaft ( 61 ), a circular disc ( 62 ) perpendicular to the revolution shaft ( 61 ), and a plurality of impeller blades ( 63 ) each provided substantially perpendicular to the circular disc ( 62 ) but curved with respect to a radial line passing the center axis of the revolution shaft ( 61 ). The outer diameter D 1 of the fan ( 6 ) and the inner diameter D 2 of the outlet ( 9 ) of airflow of the air tunnel ( 3 ) are selected so that the value D 1 /D 2 in the region equal to or larger than 1.0 and equal to or smaller than 1.45, (1.0≦D 1 /D 2 ≦1.45). Thereby, the hair dryer ( 1 ) can generate strong airflow with a constant volume without increasing rotation number of the motor ( 7 ) and without enlarging the outer diameter of the fan ( 6 ) by reducing the pressure loss due to the air tunnel.
1 . A hair dryer comprising a housing having a substantially cylindrical air tunnel, a fan provided in the air tunnel, a motor for revolving the fan, and a heater, wherein
the fan is a centrifugal fan having a revolution shaft, a circular disc provided substantially perpendicular to a center axis of the revolution shaft, and a plurality of impeller blades each provided substantially perpendicular to the circular disc but curved with respect to a radial line passing the center axis of the revolution shaft; and
when an outer diameter of the fan is designated by a symbol D 1 and an inner diameter of an outlet of airflow of the air tunnel of the housing is designated by a symbol D 2 , a value of D 1 /D 2 is in a region equal to or larger than 1.0 and equal to or smaller than 1.45 (1.0≦D 1 /D 2 ≦1.45).
2 . The hair dryer in accordance with claim 1 , wherein
when an inner diameter of the air tunnel surrounding the fan is designated by a symbol D 3 , a value of D 1 /D 3 is in a range equal to or larger than 0.1 and equal to or smaller than 0.75 (0.6≦D 1 /D 3 ≦0.75).
3 . The hair dryer in accordance with claim 1 , wherein
the circular disc of the fan is gently slanted toward a downstream side in an airflow path from the revolution axis to outer periphery thereof.
4 . The hair dryer in accordance with claim 1 , wherein
neighboring two impeller blades of the fan are formed so that a distance between them becomes gradually wider from inner portion near to the revolution axis to outer periphery of the circular disc.
5 . The hair dryer in accordance with claim 2 , wherein
the circular disc of the fan is gently slanted toward a downstream side in an airflow path from the revolution axis to outer periphery thereof.
6 . The hair dryer in accordance with claim 2 , wherein
neighboring two impeller blades of the fan are formed so that a distance between them becomes gradually wider from inner portion near to the revolution axis to outer periphery of the circular disc.