Fan unit air flow control

Abstract

A fan unit comprises a top having an inlet opening, at least one side for enclosing the fan unit, and an outlet opening. A fan blower is disposed on a blower mounting, the fan blower being for drawing air through the inlet opening and for discharging air through the outlet opening. At least one pair of guide baffles extends inwardly from a lower end of the at least one side towards the outlet opening, the pair of guide baffles and the blower mounting forms an air flow channel therebetween. The air flow channel creates a constriction on air flow to raise air pressure within the air flow channel. This creates substantially mono-directional air flow in the air flow channel and through the outlet opening. The air flow therefore has reduced turbulence such that noise from said fan unit is minimised.

1 . A fan unit comprising: 
 a top having an inlet opening,    at least one side for enclosing the fan unit,    an outlet opening,    a fan blower disposed on a mounting, the fan blower being for drawing air through the inlet opening and for discharging air through the outlet opening,    at least one pair of guide baffles extending inwardly from a lower end of the at least one side towards the outlet opening,    said at least one pair of guide baffles and the mounting forming an air flow channel therebetween,    the air flow channel creating a construction on air flow to raise air pressure within the air flow channel to thereby create substantially mono-directional air flow in the air flow channel and through the outlet opening with reduced turbulence such that noise from said fan unit is minimised.    
   
   
       2 . A fan unit as claimed in  claim 1 , wherein the mounting is a blower mounting.  
   
   
       3 . A fan unit as claimed in  claim 1 , wherein there are provided two pairs of guide baffles disposed within the fan unit, the guide baffles being mutually perpendicular.  
   
   
       4 . A fan unit as claimed in  claim 3 , wherein the guide baffles define the outlet opening.  
   
   
       5 . A fan unit as claimed in  claim 1 , wherein the guide baffles are disposed at an angle of between 90° and 60° with the at least one side.  
   
   
       6 . A fan unit as claimed in  claim 5 , wherein the angle is 90°.  
   
   
       7 . A fan unit as claimed in  claim 1 , wherein the guide baffles are perforated.  
   
   
       8 . A fan unit as claimed in  claim 7 , wherein the perforations are over only a part of the guide baffles.  
   
   
       9 . A fan unit as claimed in  claim 7 , wherein the perforations are over all of the guide baffles.  
   
   
       10 . A fan unit as claimed in  claim 8 , wherein the perforations are covered by a cloth.  
   
   
       11 . A fan unit as claimed in  claim 1 , wherein the outlet opening is a shape selected from the group consisting of: circular, triangular, square, rectangular, pentagonal, and octagonal.  
   
   
       12 . A fan unit as claimed in any  claim 1 , wherein the guide baffles are curved.  
   
   
       13 . A fan unit as claimed in  claim 1 , further including at least one pair of plates disposed within the fan unit and extending between the top and the at least one side, each of the at least one pair of plates defining an enclosed space between each of the at least one pair of plates, the top and the at least one side.  
   
   
       14 . A fan unit as claimed in  claim 13 , wherein the plates are at an angle to the top of between 30° and 60°.  
   
   
       15 . A fan unit as claimed in  claim 14 , wherein the angle is 45°.  
   
   
       16 . A fan unit as claimed in  claim 13 , wherein there are two pairs of plates, the plates being mutually perpendicular.  
   
   
       17 . A fan unit as claimed in  claim 13 , wherein at least one pair of the plates is perforated.  
   
   
       18 . A fan unit as claimed in  claim 17 , wherein the perforations are over all of the at least one pair of plates.  
   
   
       19 . A fan unit as claimed in  claim 17 , wherein the perforations are over a part only of the at least one pair of plates.  
   
   
       20 . A fan unit as claimed in  claim 17 , wherein the perforations are covered by a cloth.  
   
   
       21 . A fan unit as claimed in  claim 13 , wherein the plates are curved.  
   
   
       22 . A fan unit as claimed in  claim 13 , wherein the enclosed space is at least partially filled with a noise insulating material.  
   
   
       23 . A fan unit as claimed in  claim 1 , wherein a noise insulating material is used to line an internal surface of one or more selected from the group consisting of: the at least one side, the top, the guide baffles, and the plates.  
   
   
       24 . A fan unit as claimed in  claim 1 , wherein the blower mounting has a noise insulating material attached to a surface thereof.  
   
   
       25 . A fan unit as claimed in  claim 24 , wherein the blower mounting is in the form of an internal tray with depending side walls, the noise insulating material being located in the tray.  
   
   
       26 . A fan unit as claimed in  claim 1 , wherein the top has a central opening, the central opening having an inlet cover, the inlet opening being in the inlet cover.  
   
   
       27 . A fan unit as claimed in  claim 1 , further including a filter located below the outlet opening.  
   
   
       28 . A fan unit as claimed in  claim 1 , wherein the at least one side comprises four mutually perpendicular side walls, the side walls also being perpendicular to the top.  
   
   
       29 . A fan unit as claimed in  claim 1 , wherein baffles employed in the fan unit are selected from the group consisting of: diffusion baffles and guide baffles.  
   
   
       30 . A method to control air flow, using a fan unit comprising: 
 a top having an inlet opening,    at least one side for enclosing the fan unit,    an outlet opening,    a fan blower disposed on a blower mounting the fan blower being for drawing air through the inlet opening and for discharging air through the outlet opening,    at least one pair of guides extending inwardly from a lower end of the at least one side towards the outlet opening,    said at least one pair of guides and the blower mounting forming an air flow channel therebetween, the air flow channel creating a constructions on air flow to raise air pressure within the air flow channel to create substantially mono-directional air flow in the air flow channel and through the outlet opening with reduced turbulence such that noise from said fan unit is minimised.