Fan Device with a Preheat Circulation Channel

Abstract

A fan device includes a base unit having at least one air inlet and an outer tube that defines an accommodation space fluidly communicating with the air inlet, and a cover unit having a receiving chamber fluidly communicating with the accommodation space, an air outlet fluidly communicating with the receiving chamber, and a lower seat including spaced apart inner and outer annular walls, and a connecting wall interconnecting the annular walls. A preheat inner tube divides the accommodation space into a heating chamber and a preheat circulation channel that fluidly communicates with each other. A fan unit is disposed in the receiving chamber. A heating unit includes a heating component disposed in the heating chamber.

What is claimed is: 
     
         1 . A fan device comprising:
 a base unit having at least one air inlet and including an outer tube that defines an accommodation space fluidly communicating with said at least one air inlet;   a cover unit disposed on said base unit and having a receiving chamber fluidly communicating with said accommodation space, and an air outlet fluidly communicating with said receiving chamber, said cover unit including a lower seat, said lower seat including an inner annular wall, an outer annular wall spaced apart from said inner annular wall, and a connecting wall interconnecting said inner and outer annular walls;   a preheat inner tube disposed in and dividing said accommodation space into a heating chamber defined by said preheat inner tube and a preheat circulation channel that is defined cooperatively by said preheat inner tube, said connecting wall and said outer tube and that fluidly communicates with said heating chamber, said preheat inner tube having a top portion disposed in said inner annular wall of said lower seat;   a fan unit disposed in said receiving chamber; and   a heating unit including at least one heating component disposed in said heating chamber;   wherein, when said fan unit is activated, air flows from said air inlet into said preheat circulation channel, and from said preheat circulation channel, the air flows consecutively through said heating chamber and said receiving chamber and out into an external environment through said air outlet.   
     
     
         2 . The fan device as claimed in  claim 1 , wherein said base unit further includes a base plate having an annular outer groove, and said outer tube has a bottom end engaged with said annular outer groove. 
     
     
         3 . The fan device as claimed in  claim 2 , wherein said air inlet is formed in said outer tube and is located between said lower seat and said base plate. 
     
     
         4 . The fan device as claimed in  claim 1 , wherein said air inlet is formed in said base plate between said preheat inner tube and said outer tube. 
     
     
         5 . The fan device as claimed in  claim 4 , wherein said base plate further has an annular inner groove spaced apart from said annular outer groove, and an annular middle groove between said annular inner and outer grooves, said base unit further including a middle tube that is disposed between said preheat inner tube and said outer tube and that divides said preheat circulation channel into an inner channel section between said middle tube and said preheat inner tube and an outer channel section between said middle and outer tubes, said middle tube having a bottom portion engaged with said middle groove, and wherein, said inner and outer channel sections, said heating chamber and said receiving chamber all fluidly communicate with one another, and said air inlet is located between said middle and outer tubes. 
     
     
         6 . The fan device as claimed in  claim 1 , wherein said base plate further has a central plate portion surrounded by said annular inner groove, said heating unit further including a reflective plate disposed on said base plate corresponding in position to said central plate portion and located within said heating chamber, and at least one cross bar disposed in said heating chamber and contacting said at least one heating component. 
     
     
         7 . The fan device as claimed in  claim 6 , wherein said reflective plate has an inverted bowl shape with a peripheral wall that tapers from a bottom end to a top end thereof. 
     
     
         8 . The fan device as claimed in  claim 1 , wherein said cover unit further includes an upper seat disposed above and cooperating with said lower seat to define said air outlet, said lower seat further including a plurality of angularly spaced-apart studs that protrude from a top end of said outer annular wall toward said upper seat and that divide said air outlet into a plurality of air outlet openings, said fan unit including a fan disposed between said upper and lower seats, and a motor that drives said fan. 
     
     
         9 . The fan device as claimed in  claim 8 , wherein said cover unit further includes a top cover disposed on and covering a top end of said outer tube, and a handle disposed on said top cover, said top cover being formed with a plurality of ventilation windows fluidly communicating with said air outlet openings, respectively. 
     
     
         10 . The fan device as claimed in  claim 9 , wherein said fan unit further includes a fan control circuit board disposed above said upper seat and connected to said top cover, said heating unit further including a heating control circuit board, said base unit further including an insulating shell connected to said base plate opposite to said reflective plate and accommodating said heating control circuit board. 
     
     
         11 . The fan device as claimed in  claim 10 , wherein said base unit further includes at least three leg poles disposed angularly spaced apart from each other beneath said base plate and having bottom ends lower than a bottom end of said base plate.