Fan assembly

Abstract

A fan assembly ( 10 ) includes a housing ( 20 ) with an air inlet ( 70 ), a fan inlet ( 60 ), and an air outlet ( 80 ). The fan assembly further includes an impeller ( 30 ) and a motor ( 40 ) configured to drive the impeller, the impeller having a plurality of circumferentially positioned spaced blades ( 34 ). An air-permeable guard ( 50 ) is positioned between the air inlet and the fan inlet to prevent users from touching the impeller ( 30 ), and is spaced a first distance ( 54 ) from the fan inlet ( 60 ), and a second distance from the air inlet ( 70 ) so that a filter ( 90 ) may be provided between the air inlet ( 70 ) and the air-permeable guard ( 50 ). Preferably, the first distance ( 54 ) is such so as to allow incoming air to at least partially rotate prior to entering the fan inlet. Preferably, the plurality of circumferentially positioned spaced blades ( 34 ) is positioned circumferentially around a domed center ( 32 ) of the impeller ( 30 ), the domed center ( 32 ) facing the fan inlet ( 60 ), and the domed center ( 32 ) co-rotates with the spaced blades ( 34 ).

1 . A fan assembly comprising:
 a housing comprising an air inlet, a fan inlet, and an air outlet;   an impeller between the fan inlet and the air outlet the impeller comprising a plurality of circumferentially positioned spaced blades;   a motor configured to drive the impeller;   an air-permeable guard positioned between the air inlet and the fan inlet to prevent users from touching the impeller, wherein the air-permeable guard is spaced a first distance from the fan inlet, and a second distance from the air inlet, the air-permeable guard having a larger cross-sectional area than a cross-sectional area of the fan inlet, and   a filter between the air inlet and the air-permeable guard, the filter having a larger cross-sectional area than the cross-sectional area of the fan inlet,   wherein an air flow path between the filter and the fan inlet has a substantially same cross-sectional area that is larger than the cross-sectional area of the fan inlet over a distance that is a least 15 mm.   
     
     
         2 . The fan assembly of  claim 1 , wherein the first distance is configured to allow incoming air to at least partially rotate prior to entering the fan inlet. 
     
     
         3 . The fan assembly of  claim 1 , wherein the plurality of circumferentially positioned spaced blades is positioned circumferentially around a domed center of the impeller, the domed center facing the fan inlet, and wherein the domed center co-rotates with the spaced blades. 
     
     
         4 . The fan assembly according to  claim 3 , wherein the domed center of the impeller comprises a plurality of spokes. 
     
     
         5 . The fan assembly according to  claim 3 , wherein a maximum height of the domed center is approximately 1 to 75% of a maximum height of the impeller. 
     
     
         6 . The fan assembly according to  claim 3 , wherein a maximum width of the domed center is approximately 20 to 95% of a maximum width of the impeller. 
     
     
         7 . The fan assembly according to  claim 1 , wherein the first distance is at least 15 mm. 
     
     
         8 . The fan assembly according to  claim 1 , wherein the first distance is smaller than 25 mm. 
     
     
         9 . The fan assembly according to  claim 1 , comprising an impeller housing having a volute (V) surrounding the impeller, and having a part (V 1 ) towards the air outlet that is tangential to fan blades of the impeller  30 . 
     
     
         10 . The fan assembly according to  claim 1 , wherein the air outlet has plates that are aligned with an air flow (F).