Fan and fan housing thereof having flapper

Abstract

A fan includes a motor base, a motor, an impeller, and a fan housing. The fan housing accommodates the motor base, the impeller, and the motor, and includes at least one flapper disposed at the corner of the fan housing via a plurality of connecting elements for covering the opening of the fan housing to prevent the air backflow.

1 . A fan comprising:
 a fan housing with an opening;   a motor base disposed in the fan housing; and   at least one flapper pivotally coupled to a corner of the fan housing for covering the opening.   
   
   
       2 . The fan according to  claim 1 , wherein the flapper is connected to the fan housing via at least one connecting element. 
   
   
       3 . The fan according to  claim 1 , wherein the flapper is disposed at an outlet side of the fan housing corresponding to a peripheral edge of the motor base. 
   
   
       4 . The fan according to  claim 1 , wherein the fan housing further comprises a cylindrical portion and an outwardly expanding portion, and the motor base is connected to the cylindrical portion via a plurality of guiding vanes. 
   
   
       5 . The fan according to  claim 1 , wherein the flapper is connected to a nearby fixing aperture at the corner of the fan housing. 
   
   
       6 . The fan according to  claim 2 , further comprising a plurality of restricting elements disposed adjacent to the connecting elements. 
   
   
       7 . The fan according to  claim 6 , wherein the restricting element and the connecting element are integrally formed as a single unit. 
   
   
       8 . The fan according to  claim 6 , wherein the restricting element is integrally formed on the corner of the fan housing. 
   
   
       9 . The fan according to  claim 2 , wherein the flapper and the connecting element are integrally formed as a single unit. 
   
   
       10 . The fan according to  claim 1 , wherein the maximum open angle of the flapper is smaller than or equal to 90 degrees. 
   
   
       11 . The fan according to  claim 1 , wherein the flapper is connected to the corner of the fan housing by pivoting, locking, clipping or wedging. 
   
   
       12 . The fan according to  claim 1 , wherein the fan is an axial flow fan or a centrifugal fan. 
   
   
       13 . The fan according to  claim 1 , wherein the flapper is positioned at the same plane of the opening of the fan housing without protruding out of the fan housing. 
   
   
       14 . The fan according to  claim 1 , wherein the flapper has a protruding element and the fan housing comprises a groove formed on an inner wall of the fan housing corresponding to the protruding element.