Hot-air heater

Abstract

Because the air trunk area of the air blowing passage on the downstream side of the air-blowing fan was kept almost constant in a conventional hot-air heater, an electric heater provided in this air blowing passage provided air trunk resistance by itself making it necessary to increase the rotation speed of the air blowing fan thereby resulting in the operating noise growing louder which, in turn, posed a problem. Therefore, an expansion 35 was formed along the air blowing passage 32 that passes from the intake opening 11 b through the exhaust opening 12 b . This expansion functions as a storage portion that contains the electric heater 3.

What is claimed is:  
     
         1 . A hot-air heater comprising: 
 (a) an air-blowing passage leading from an inlet to an outlet;    (b) an air-blowing fan and an electric heater, which are provided along said air-blowing passage, so that when said air-blowing fan is operated to suck air into said air-blowing passage through said inlet, said air is heated by said electric heater to provide hot air, which is blasted out of said outlet into a room,    wherein an expansion is formed on said air-blowing passage as a storage portion to contain said electric heater.    
     
     
         2 . The hot-air heater according to  claim 1 , wherein the air trunk area decreases smoothly on the downstream side of said expansion.  
     
     
         3 . The hot-air heater according to  claim 1 , wherein a cross-sectional area of the exit and that of the outlet of said expansion are each increased compared to that of the entrance of said expansion.  
     
     
         4 . The hot-air heater according to  claim 1 , wherein said air-blowing passage has a bent portion obtained by bending itself somewhere along it and said air-blowing fan is provided with a moving vane positioned on said bent portion, so that said expansion positioned on the downstream side of said bent portion is provided with said electric heater in such a manner that it intersects with said air-blowing passage, the distance between the inner wall of said expansion positioned on the inner side of said bent portion and said electric heater is increased compared to that between the inner wall of said expansion positioned on the outer side of said bent portion and said electric heater.  
     
     
         5 . The hot-air heater according to  claim 1 , wherein heat insulation means are provided around said expansion of said electric heater.  
     
     
         6 . The hot-air heater according to  claim 1 , wherein said expansion is adapted to have a double structure, which contains airspace.