Dryer

Abstract

A dryer includes a tubular portion, an axial flow impeller located inside the tubular portion, a motor, a heater support portion positioned forward of the axial flow impeller inside the tubular portion, and a heater. The axial flow impeller includes a plurality of blades arranged in a circumferential direction. The heater support portion includes a plurality of plate-shaped portions extending radially outward from the blowing axis in a cross-section perpendicular or substantially perpendicular to the blowing axis. The number of positions at which circumferential positions of radially outer ends of the second edges of the blades and circumferential positions of the plate-shaped portions overlap with each other is always one or less regardless of a rotational position of the axial flow impeller.

What is claimed is: 
     
         1 . A dryer comprising:
 a tubular portion extending in an axial direction around a blowing axis;   an axial flow impeller located inside the tubular portion;   a motor configured to rotate the axial flow impeller about the blowing axis or a rotation axis extending parallel or substantially parallel to the blowing axis;   a heater support portion positioned forward of the axial flow impeller inside the tubular portion; and   a heater supported by the heater support portion inside the tubular portion; wherein   the axial flow impeller includes a plurality of blades extending in a circumferential direction;   the heater support portion includes a plurality of plate-shaped portions extending radially outward from the blowing axis in a cross-section perpendicular or substantially perpendicular to the blowing axis;   both circumferential edges of each blade include a first edge and a second edge positioned forward of the first edge with respect to a direction parallel to or substantially parallel to the blowing axis; and   a number of positions at which circumferential positions of radially outer ends of the second edges of the blades and circumferential positions of the plate-shaped portions overlap with each other is always one or less regardless of a rotational position of the axial flow impeller.   
     
     
         2 . The dryer according to  claim 1 , wherein a number of positions at which circumferential positions of portions of the second edges of the blades, each portion being radially outward of a middle of the second edge of the blade, and the circumferential positions of the plate-shaped portions overlap with each other is always one or less regardless of the rotational position of the axial flow impeller. 
     
     
         3 . The dryer according to  claim 2 , wherein
 both the plurality of blades and the plurality of plate-shaped portions are arranged at regular intervals in the circumferential direction; and   a number of blades included in the axial flow impeller and a number of plate-shaped portions included in the heater support portion do not possess common denominators, except for one, and are not divisible with respect to one another.   
     
     
         4 . The dryer according to  claim 2 , further comprising a plurality of stationary vanes positioned forward of the axial flow impeller and rearward of the heater support portion, and positioned in the circumferential direction radially outside of the motor. 
     
     
         5 . The dryer according to  claim 4 , wherein a number of positions at which the circumferential positions of the radially outer ends of the second edges of the blades and circumferential positions of the stationary vanes overlap with each other is always one or less regardless of the rotational position of the axial flow impeller. 
     
     
         6 . The dryer according to  claim 5 , wherein
 both the plurality of blades and the plurality of stationary vanes are arranged at regular intervals in the circumferential direction; and   a number of blades included in the axial flow impeller and a number of stationary vanes do not possess common denominators, except for one, and are not divisible with respect to one another.   
     
     
         7 . The dryer according to  claim 6 , wherein the number of stationary vanes is an integral multiple of a number of plate-shaped portions included in the heater support portion. 
     
     
         8 . The dryer according to  claim 7 , wherein an axially rearward edge of each of all the plate-shaped portions included in the heater support portion overlaps at least in part with an axially forward edge of one of the stationary vanes. 
     
     
         9 . The dryer according to  claim 5 , wherein a number of stationary vanes is an integral multiple of a number of plate-shaped portions included in the heater support portion. 
     
     
         10 . The dryer according to  claim 9 , wherein an axially rearward edge of each of all the plate-shaped portions included in the heater support portion overlaps at least in part with an axially forward edge of one of the stationary vanes. 
     
     
         11 . The dryer according to  claim 1 , wherein
 both the plurality of blades and the plurality of plate-shaped portions are arranged at regular intervals in the circumferential direction; and   a number of blades included in the axial flow impeller and a number of plate-shaped portions included in the heater support portion are do not possess common denominators, except for one, and are not divisible with respect to one another.   
     
     
         12 . The dryer according to  claim 11 , wherein (Na, Nb)=(4, 5), (4, 7), (6, 5), or (6, 7), where Na denotes the number of plate-shaped portions included in the heater support portion and Nb denotes the number of blades included in the axial flow impeller. 
     
     
         13 . The dryer according to  claim 1 , further comprising a plurality of stationary vanes positioned forward of the axial flow impeller and rearward of the heater support portion, and positioned in the circumferential direction radially outside of the motor. 
     
     
         14 . The dryer according to  claim 13 , wherein a number of positions at which the circumferential positions of the radially outer ends of the second edges of the blades and circumferential positions of the stationary vanes overlap with each other is always one or less regardless of the rotational position of the axial flow impeller. 
     
     
         15 . The dryer according to  claim 14 , wherein
 both the plurality of blades and the plurality of stationary vanes are arranged at regular intervals in the circumferential direction; and   a number of blades included in the axial flow impeller and a number of stationary vanes do not possess common denominators, except for one, and are not divisible with respect to one another.   
     
     
         16 . The dryer according to  claim 15 , wherein the number of stationary vanes is an integral multiple of a number of plate-shaped portions included in the heater support portion. 
     
     
         17 . The dryer according to  claim 16 , wherein an axially rearward edge of each of all the plate-shaped portions included in the heater support portion overlaps at least in part with an axially forward edge of one of the stationary vanes. 
     
     
         18 . The dryer according to  claim 14 , wherein a number of stationary vanes is an integral multiple of a number of plate-shaped portions included in the heater support portion. 
     
     
         19 . The dryer according to  claim 18 , wherein an axially rearward edge of each of all the plate-shaped portions included in the heater support portion overlaps at least in part with an axially forward edge of one of the stationary vanes. 
     
     
         20 . The dryer according to  claim 1 , wherein the plurality of blades are arranged at irregular intervals in the circumferential direction.