Fan, more particularly radial or diagonal fan

Abstract

A fan (1), more particularly a radial or diagonal fan, comprising a motor (4), an impeller (3) driven in rotation by the motor (4), an inlet nozzle (5) and a nozzle plate (2) extending around the inlet nozzle (5), wherein the impeller (3) essentially consists of a base disk (10), a cover disk (8) and several wings (9) extending between them, the nozzle plate (2) has an edge folded towards the pressure side and the cover disk (8) is rounded on its outer edge towards the suction side, and wherein the fold (6) of the nozzle plate (2) and the rounding of the cover disk (8) are shaped and dimensioned in such a way that the outflow from the impeller (3) close to the cover disk interacts with the bend of the nozzle plate (2).

1 . A fan ( 1 ), comprising:
 motor ( 4 ),   an impeller ( 3 ) driven in rotation by the motor ( 4 ),   an inlet nozzle ( 5 ) and   a nozzle plate ( 2 ) extending around the inlet nozzle ( 5 ),   wherein the impeller ( 3 ) essentially consists of a base disk ( 10 ), a cover disk ( 8 ) and several wings ( 9 ) extending between them,   and wherein the nozzle plate ( 2 ) has an edge folded towards the pressure side and the cover disk ( 8 ) is rounded on its outer edge towards the suction side,   and wherein the fold ( 6 ) of the nozzle plate ( 2 ) and the rounding of the cover disk ( 8 ) are shaped and dimensioned in such a way that the outflow from the impeller ( 3 ) close to the cover disk interacts with the edge of the nozzle plate ( 2 ).   
     
     
         2 . The fan according to  claim 1 , wherein the section at a plane through the fan axis which can be assigned to a circumferential position of the impeller ( 3 ) or of the shroud ( 8 ) or of the nozzle plate ( 2 ), the tangential extension of the inner shroud contour facing the wings ( 9 ) intersects—at its radially outer edge—the nozzle plate ( 2 ), viewed including its bend ( 6 ), over at least 90%, preferably over 100% of the circumferential positions. 
     
     
         3 . The fan according to  claim 1 , wherein the rounding of the cover disk ( 8 ) is designed in the form of a strong curvature ( 7 ). 
     
     
         4 . The fan according to the  claim 1 , wherein an inner contour of the rounding and thus of the outer edge of the cover disk ( 8 ), at the outer end of the cover disk ( 8 ), in the area of the impeller exit, gives the air flow an air exit direction which is defined through a straight, tangential extension of the cover disk ( 8 ). 
     
     
         5 . The fan according to  claim 4 , wherein the air exit direction is constant or variable over the circumference of the cover disk ( 8 ). 
     
     
         6 . The fan according to  claim 4 , wherein the air exit direction is directed backwards with respect to the main flow direction, towards the nozzle plate ( 2 ). 
     
     
         7 . The fan according to  claim 6 , wherein the air exit direction, at the outer end of the cover disk ( 8 ), i.e., at its curvature area ( 7 ), has an angle α ( 26 ) of more than 35°, preferably more than 45°, to the radial direction. 
     
     
         8 . The fan according to  claim 1 , wherein an imaginary extension of the cover disk ( 8 ), starting from its curvature area ( 7 ), preferably over the entire circumference or over a large area of the circumference of more than 95%, intersects with the nozzle plate ( 2 ) or its fold ( 6 ). 
     
     
         9 . The fan according to  claim 1 , wherein a ratio of an air exit diameter D D  ( 22 ) of the inlet nozzle ( 5 ) to an air exit diameter D L  ( 18 ) of the impeller ( 3 ) at the outer edge of the cover disk ( 8 ) is greater than or equal to 70%, preferably greater than or equal to 75%. 
     
     
         10 . The fan according to  claim 1 , wherein a ratio of an axial height c ( 23 ) of the inlet nozzle ( 5 ) to an air exit diameter D L  ( 18 ) of the impeller ( 3 ) at the outer edge of the cover disk ( 8 ) is less than or equal to 12%. 
     
     
         11 . The fan according to  claim 1 , wherein a ratio of an axial distance a ( 25 ) between an air flow exit on the cover disk ( 8 ) and the open end of the fold ( 6 ) of the nozzle plate ( 2 ) to air exit diameter D L  ( 18 ) of the impeller ( 3 ) at the outer edge of the cover disk ( 8 ) is less than or equal to 20%. 
     
     
         12 . The fan according to  claim 9  in that a+b<w−D L  or a+b<(w−D L )*tan (α), wherein w=radial width of the nozzle plate ( 2 ), which represents the smallest side length of a rather rectangular contour of the nozzle plate ( 2 ), and b=axial height of the outer fold ( 6 ) of the nozzle plate ( 2 ). 
     
     
         13 . The fan according to  claim 1 , wherein the nozzle plate ( 2 ) has a rectangular, preferably square outer contour. 
     
     
         14 . The fan according to  claim 1 , wherein the cover disk ( 8 ) has a larger outer diameter than the base disk ( 10 ). 
     
     
         15 . The fan according to  claim 14 , wherein a ratio of the outer diameter of the base disk ( 10 ) to the outer diameter of the cover disk ( 8 ) is in the range from/between 85% and/to 95%. 
     
     
         16 . The fan according to  claim 1 , wherein an axial height b ( 24 ) of the outer fold ( 6 ) of the nozzle plate ( 2 ) is at least 2%, advantageously at least 3%, of an outer diameter D L  ( 18 ) of the cover disk ( 8 ) of the impeller ( 3 ) at the curvature area ( 7 ).