Fan wheel

Abstract

A fan wheel including a first and second end plate, and blades arranged between the first and the second end plate and joined to the first and the second end plate. In order to obtain an efficient fan wheel the outer surfaces of the blades are inclined in relation to the rotation axis of the fan wheel, the first and second end plate have outer portions which protrude radially outward beyond the outer edges of the blades, the outer portion of the first end plate is generally curved or inclined towards the second end plate and the outer portion of the second end plate is generally curved or inclined away from the first end plate, and the blades are profiled to have a profile where the thickness of the blades vary between the outer edges of the blades and the inner edges of the blades.

1 . A fan wheel comprising:
 a first and second end plate arranged at a mutual distance from each other, the first end plate having an opening which allows inflow to the fan wheel, and   blades arranged between the first and the second end plate and joined to the first and the second end plate, whereby outer edges of the blades together with the first and second end plate delimit openings allowing outflow from the fan wheel, and wherein   outer surfaces of the blades are inclined in relation to a rotation axis of the fan wheel such that the distance between the outer surfaces and the rotation axis is bigger at the first end plate than at the second end plate,   the first and second end plates have outer portions which protrude radially outward beyond the outer edges of the blades such that an outwardly open diffusion space is delimited by the outer portions of the first and second end plates and the blades,   the outer portion of the first end plate is generally curved or inclined towards the second end plate and the outer portion of the second end plate is generally curved or inclined away from the first end plate, and   the blades are profiled to have a profile where the thickness of the blades varies between the outer edges of the blades and the inner edges of the blades while the thickness of the blades remains constant in a width direction of the blades.   
     
     
         2 . The fan wheel according to  claim 1 , wherein the width of the diffusion space increases outwardly. 
     
     
         3 . The fan wheel according to  claim 1 , wherein the fan wheel is entirely manufactured of metal. 
     
     
         4 . The fan wheel according to  claim 1 , wherein the diffusion space does not contain additional plates, guides or elements between the outer portions of the first and second end plate. 
     
     
         5 . The fan wheel according to  claim 1 , wherein the diameter of the first end plate is larger than the diameter of the second end plate. 
     
     
         6 . The fan wheel according to  claim 1 , wherein the inner edges of the blades are inclined in relation to the rotation axis of the fan wheel such that an angle of direction of the locus of the blade leading edge intersection points with a meridian plane is 15° to 20°, most preferably about 19°. 
     
     
         7 . The fan wheel according to  claim 1 , wherein the width of the diffusion space increases outwardly with an angle of 16° to 22°, most preferably about 19°. 
     
     
         8 . The fan wheel according to  claim 1 , wherein the outer portion of the first end plate protrudes radially outward beyond the outer edges of the blades with a distance that is at least 5 to 10% of a diameter of the first end plate. 
     
     
         9 . The fan wheel according to  claim 1 , wherein the thickness of the cross-section of the profiled blades is constant in the width direction of the blades between the first end plate and the second end plate along a line which is parallel with the inner edges of the blades. 
     
     
         10 . The fan wheel according to  claim 1 , wherein the blades have outer edges and inner edges, and at least a part of the outer edges are parallel with the inner edges. 
     
     
         11 . The fan wheel according to  claim 1 , wherein the outer edges of the blades protrude in the radial direction to a diameter which diminishes stepwise from the first end plate towards the second end plate such that at the first end plate and at the second end plate the outer edges of the blades have a first straight section and a second straight section where the outer edges are parallel and between the first straight section and the second straight section the outer edges of the blades have a third section, where the outer edges of the blades extend in a different direction than at the first straight section and at the second straight section. 
     
     
         12 . A method comprising:
 arranging a fan wheel according to  claim 1  in an air handling box having walls separating the fan wheel from a surrounding environment,   connecting an inlet opening of the air handling box to the opening allowing inflow into the fan wheel via an inlet cone, and   conducting air via an outlet opening from the air handling box, the outlet opening being arranged on an opposite side of the fan wheel as compared to the inlet opening of the air handling box.   
     
     
         13 . A method for manufacturing a fan wheel, the method comprises:
 manufacturing a first end plate with a center opening of a metal material,   manufacturing a second end plate of a metal material,   extrusion of a metal material to an elongated profile bar having a thickness varying over the width of the elongated profile bar,   cutting the extruded elongated profile bar into profiled blades,   arranging the profiled blades between the first and second end plate in a position where outer surfaces of the blades are inclined in relation to a rotation axis of the fan wheel and a distance between the outer surfaces of the blades and the rotation axis is bigger at the first end plate than at the second end plate, and arranging the profiled blades in a position where the first and second end plate have outer portions protruding radially outward beyond the outer edges of the blades and form an an outwardly open diffusion space, and   attaching the profiled blades to the first and second end plate to obtain a fan wheel having an inflow opening consisting of the center opening of the first end plate and outflow openings delimited by the first and second end plate and outer edges of the blades.