Patent Publication Number: US-11022146-B2

Title: Fan assembly

Description:
REFERENCE TO RELATED APPLICATIONS 
     This application claims the priority of United Kingdom Application No. 1720058.5, filed Dec. 1, 2017, the entire contents of which are incorporated herein by reference. 
     FIELD OF THE INVENTION 
     The present invention relates to a fan assembly and a nozzle for a fan assembly. 
     BACKGROUND OF THE INVENTION 
     A conventional domestic fan typically includes a set of blades or vanes mounted for rotation about an axis, and drive apparatus for rotating the set of blades to generate an airflow. The movement and circulation of the airflow creates a ‘wind chill’ or breeze and, as a result, the user experiences a cooling effect as heat is dissipated through convection and evaporation. The blades are generally located within a cage which allows an airflow to pass through the housing while preventing users from coming into contact with the rotating blades during use of the fan. 
     U.S. Pat. No. 2,488,467 describes a fan which does not use caged blades to project air from the fan assembly. Instead, the fan assembly comprises a base which houses a motor-driven impeller for drawing an airflow into the base, and a series of concentric, annular nozzles connected to the base and each comprising an annular outlet located at the front of the nozzle for emitting the airflow from the fan. Each nozzle extends about a bore axis to define a bore about which the nozzle extends. 
     Each nozzle is in the shape of an airfoil may therefore be considered to have a leading edge located at the rear of the nozzle, a trailing edge located at the front of the nozzle, and a chord line extending between the leading and trailing edges. In U.S. Pat. No. 2,488,467 the chord line of each nozzle is parallel to the bore axis of the nozzles. The air outlet is located on the chord line, and is arranged to emit the airflow in a direction extending away from the nozzle and along the chord line. 
     Another fan assembly which does not use caged blades to project air from the fan assembly is described in WO 2010/100451. This fan assembly comprises a cylindrical base which also houses a motor-driven impeller for drawing a primary airflow into the base, and a single annular nozzle connected to the base and comprising an annular mouth/outlet through which the primary airflow is emitted from the fan. The nozzle defines an opening through which air in the local environment of the fan assembly is drawn by the primary airflow emitted from the mouth, amplifying the primary airflow. The nozzle includes a Coanda surface over which the mouth is arranged to direct the primary airflow. The Coanda surface extends symmetrically about the central axis of the opening so that the airflow generated by the fan assembly is in the form of an annular jet having a cylindrical or frusto-conical profile. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a fan assembly that can deliver either an amplified airflow or a non-amplified airflow or simultaneously deliver both an amplified airflow and a non-amplified airflow, and in doing so provide the user of the fan assembly with various options as to how air is delivered by the fan assembly. This is particularly useful when the fan assembly is configured to provide purified air as the user of a fan assembly may wish to continue to receive purified air from the fan assembly without the cooling effect produced by the provision of the amplified airflow. 
     According a first aspect there is provided a fan assembly comprising a motor-driven impeller for creating an airflow and a nozzle comprising a first air outlet. The nozzle defines a bore through which air from outside the fan assembly is drawn by any portion of the airflow that is emitted from the first outlet and which combines with the airflow emitted from the first air outlet to produce an amplified airflow. The fan assembly further comprises a second air outlet arranged such that any portion of the airflow that is emitted from the second air outlet does not draw air through the bore defined by the nozzle thereby producing a non-amplified airflow. The second air outlet may be arranged to direct any portion of the airflow that is emitted from the second air outlet such that the non-amplified airflow divaricates away from the fan assembly. 
     The airflow drawn through the fan assembly by the motor-driven impeller and emitted from the fan assembly by one or both of the first air outlet and the second air outlet is referred to hereafter as a primary airflow. Any portion of this primary airflow that is emitted from the first air outlet entrains air surrounding the nozzle, which thus acts as an air amplifier to supply both the primary airflow and the entrained air to the user. The entrained air will be referred to herein as a secondary airflow. This secondary airflow is drawn from the room space, region or external environment surrounding the nozzle. The primary airflow therefore combines with the entrained secondary airflow to form a combined, or amplified, airflow projected forward from the front of the nozzle. In contrast, any portion of the primary airflow that is emitted from the second air outlet does not entrain any significant secondary airflow and is therefore referred to herein as a non-amplified airflow. 
     Preferably, the fan assembly comprises at least one purifying assembly that is arranged to purify the airflow before the airflow is emitted from the fan assembly by any of the first air outlet and the second air outlet. 
     The nozzle preferably comprises a loop. The nozzle may have any of an annular and an elongate annular shape. The fan assembly may further comprise a fan body with the nozzle being mounted on and supported by the fan body. The fan body may then further comprise the second air outlet. The second air outlet may then be arranged to direct any portion of the airflow that is emitted from the second air outlet such that the non-amplified airflow divaricates away from the fan body. 
     Alternatively, the nozzle may comprise the second air outlet. The second air outlet may then be arranged to direct any portion of the airflow that is emitted from the second air outlet such that the non-amplified airflow divaricates away from a central axis of the bore defined by the nozzle. To do so, the second air outlet may be arranged to direct any portion of the airflow that is emitted from the second air outlet substantially perpendicularly away from the central axis of the bore defined by the nozzle. The second air outlet may therefore be arranged such that a duct of the second air outlet is substantially perpendicular relative to the central axis of the bore defined by the nozzle. 
     The second air outlet may extend around at least a portion of an external surface of the nozzle that faces in a direction that is substantially perpendicular to a central axis of the bore defined by the nozzle. 
     The first air outlet may be arranged to direct the emitted the airflow substantially parallel to a central axis of the bore defined by the nozzle. The first air outlet may be arranged such that a duct of the first air outlet is substantially parallel to a central axis of the bore defined by the nozzle. Preferably, the first air outlet is provided in an edge of the nozzle that faces in a direction that is substantially parallel to a central axis of the bore defined by the nozzle. 
     Preferably, the fan assembly further comprises a valve that is arranged to direct the airflow to one or both of the first air outlet and the second air outlet in dependence upon the position of a valve member of the valve. The valve member may be arranged to be moveable between a first end position in which the valve member directs the airflow to the first air outlet and occludes the airflow from reaching the second air outlet, and a second end position in which the valve member directs the airflow to the second air outlet and occludes the airflow from reaching the first air outlet. Preferably, the valve member is arranged such that, when located in-between the first end position and the second end position, the valve member directs a first portion of the airflow to the first air outlet and a second portion of the airflow to the second air outlet. 
     The nozzle may comprise the first air outlet, the second air outlet and an interior passage for conveying the airflow to both the first air outlet and the second air outlet, with the valve then being provided within the interior passage of the nozzle. The shape of one or both of the first air outlet and the second air outlet may then correspond to that of an aligned portion of the interior passage, and the valve may then extend around at least a portion of the interior passage of the nozzle. The valve member may then be arranged such that, in the first end position, the valve member occludes the second air outlet from the airflow within the interior passage and, in the second end position, occludes the first air outlet from the airflow within the interior passage. 
     The interior passage may be provided with a first airflow channel and a second airflow channel, the first airflow channel being arranged to direct the airflow towards the first air outlet and the second airflow channel being arranged to direct the airflow towards the second air outlet. The valve member may then be arranged such that, in the first end position, the valve member occludes the second airflow channel from the remainder of the interior passage and, in the second end position, occludes the first airflow channel from the remainder of the interior passage. 
     Preferably, a baffle is provided within the interior passage, the baffle at least partially defining at least one of the first airflow channel and the second airflow channel within the interior passage. The valve member may then be arranged to abut against the baffle in one of the first end position and the second end position to thereby occlude either the first airflow channel or the second airflow channel from the remainder of the interior passage. 
     The valve may further comprise a valve driver arranged to cause movement of the valve member to direct the airflow to one or both of the first air outlet and the second air outlet. The valve driver may comprise any of a valve motor and a manually driven dial or switch. 
     The valve driver may be arranged to cause movement of a rack, the rack being provided with a linkage to the valve member so that movement of the rack causes movement of the valve member. The linkage between the rack and the valve member is preferably provided by a cam-follower pair, a cam being provided on one of the rack and the valve member and a follower being provided on the other of the rack and the valve member and arranged to cooperate with the cam. 
     The valve driver may be arranged to cause movement of a valve actuator, the valve actuator being provided with a linkage to a valve member so that movement of the valve actuator causes movement of the valve member. The linkage between the valve actuator and the valve member is preferably provided by a cam-follower pair, a cam being provided on one of the valve actuator and the valve member and a follower being provided on the other of the valve actuator and the valve member and arranged to cooperate with the cam. The valve driver may be arranged to cause movement of a rack, the rack being connected to the valve actuator so that movement of the rack causes movement of the valve actuator. 
     The rack may have an arc shape that substantially corresponds to that of an aligned portion of the interior passage and the valve driver may then be arranged to cause circular motion of the rack. A first valve actuator may then be connected to a first end of the arc-shaped rack and a second valve actuator connected to a second end of the arc-shaped rack. A cam of a cam-follower pair linking the first valve actuator to a first valve member may then have an opposing orientation to a cam of a cam-follower pair linking the second valve actuator to a second valve member. 
     The nozzle may comprise more than one first air outlet and the valve may then comprise a valve member corresponding to each of the more than one first air outlets, each valve member being arranged to direct the airflow to a corresponding first air outlet in dependence upon the position of the valve member. Alternatively or in addition, the nozzle may comprise more than one second air outlet and the valve may then comprise a valve member corresponding to each of the more than one second air outlets, each valve member being arranged to direct the airflow to a corresponding second air outlet in dependence upon the position of the valve member. Each of the more than one valve members may then be arranged to be moveable between a first end position in which the valve member directs the airflow to a first air outlet and occludes the airflow from reaching a second air outlet, and a second end position in which the valve member directs the airflow to a second air outlet and occludes the airflow from reaching a first air outlet. 
     According a second aspect there is provided a nozzle for a fan assembly, the nozzle comprising an air inlet for receiving an airflow from the fan assembly, a first air outlet and a second air outlet. The nozzle defines a bore through which air from outside the fan assembly is drawn by any portion of the airflow that is emitted from the first outlet and which then combines with the airflow emitted from the first air outlet to produce an amplified airflow. The second air outlet is arranged such that any portion of the airflow that is emitted from the second air outlet does not draw air through the bore defined by the nozzle thereby producing a non-amplified airflow. 
     Preferably, the nozzle further comprises a valve that is arranged to direct the airflow to one or both of the first air outlet and the second air outlet in dependence upon the position of a valve member of the valve. The valve member may be arranged to be moveable between a first end position in which the valve member directs the airflow to the first air outlet and occludes the airflow from reaching the second air outlet, and a second end position in which the valve member directs the airflow to the second air outlet and occludes the airflow from reaching the first air outlet. The valve member may be arranged such that, when located in-between the first end position and the second end position, the valve member directs a first portion of the airflow to the first air outlet and a second portion of the airflow to the second air outlet. 
     The second air outlet may be arranged to direct any portion of the airflow that is emitted from the second air outlet substantially perpendicularly away from the central axis of the bore defined by the nozzle. The second air outlet may therefore be arranged such that a duct of the second air outlet is substantially perpendicular relative to the central axis of the bore defined by the nozzle. The second air outlet may extend around at least a portion of an external surface of the nozzle that faces in a direction that is substantially perpendicular to a central axis of the bore defined by the nozzle. 
     The first air outlet may be arranged to direct the emitted the airflow substantially parallel to a central axis of the bore defined by the nozzle. The first air outlet may be arranged such that a duct of the first air outlet is substantially parallel to a central axis of the bore defined by the nozzle. Preferably, the first air outlet is provided in an edge of the nozzle that faces in a direction that is substantially parallel to a central axis of the bore defined by the nozzle. 
     The nozzle may comprise an interior passage for conveying air from the air inlet to the first air outlet and second air outlet. The valve may then be provided within the interior passage of the nozzle. 
     According a third aspect there is provided a fan assembly comprising an impeller, a motor for rotating the impeller to generate an airflow, and a nozzle according to the second aspect and arranged to receive the airflow generated by the impeller. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       An embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which: 
         FIG. 1 a    is a front view of a first embodiment of a fan assembly; 
         FIG. 1 b    is a right side view of the first embodiment of the fan assembly; 
         FIG. 2  is a right side cross-section view, taken along line A-A in  FIG. 1   a;    
         FIG. 3  is a cross-sectional view through the nozzle of the fan assembly, taken along line B-B in  FIG. 1   b;    
         FIG. 4  then shows an enlarged view of a portion of the cross-section view of  FIG. 2 ; 
         FIG. 5  is a perspective view of a main body section of the fan assembly of  FIGS. 1 a    and  1   b;    
         FIG. 6 a    is an exploded view of the purifying assembly of the fan assembly of  FIGS. 1 a    and  1   b;    
         FIG. 6 b    is a rear perspective view of a perforated shroud suitable for use with the fan assembly  FIGS. 1 a    and  1   b;    
         FIG. 7  is an exploded view of the nozzle of the fan assembly of  FIGS. 1 a    and  1   b;    
         FIG. 8  is a rear perspective view of the valve of the fan assembly of  FIGS. 1 a    and  1   b;    
         FIG. 9 a    is a front view of a second embodiment of a nozzle for a fan assembly; 
         FIG. 9 b    is a right side view of the second embodiment of a nozzle for a fan assembly; 
         FIG. 10 a    is a cross-sectional view through one section of the nozzle of  FIGS. 9 a  and 9 b    taken along line B-B in  FIG. 9 b    when in a first mode of operation; 
         FIG. 10 b    is a cross-sectional view through one section of the nozzle of  FIGS. 9 a  and 9 b    taken along line B-B in  FIG. 9 b    when in a second mode of operation; 
         FIG. 11  is an exploded view of the nozzle of  FIGS. 9 a    and  9   b;    
         FIG. 12  is a front perspective view of the valve of the of the nozzle of  FIGS. 9 a    and  9   b;    
         FIG. 13 a    is a front view of a third embodiment of a nozzle for a fan assembly; 
         FIG. 13 b    is a right side view of the third embodiment of a nozzle for a fan assembly; 
         FIG. 14 a    is a cross-sectional view through one section of the nozzle of  FIGS. 9 a  and 9 b    taken along line B-B in  FIG. 13 b    when in a first mode of operation; 
         FIG. 14 b    is a cross-sectional view through one section of the nozzle of  FIGS. 9 a  and 9 b    taken along line B-B in  FIG. 13 b    when in a second mode of operation; 
         FIG. 15  is an exploded view of the nozzle of  FIGS. 13 a  and 13 b   ; and 
         FIG. 16  is a front perspective view of the valve of the nozzle of  FIGS. 13 a    and  13   b.    
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     There will now be described a fan assembly that can deliver either an amplified airflow or a non-amplified airflow or simultaneously deliver both an amplified airflow and a non-amplified airflow, and in doing so provide the user of the fan assembly with various options as to how air is delivered by the fan assembly. The term “fan assembly” as used herein refers to a fan assembly configured to generate and deliver an airflow for the purposes of thermal comfort and/or environmental or climate control. Such a fan assembly may be capable of generating one or more of a dehumidified airflow, a humidified airflow, a purified airflow, a filtered airflow, a cooled airflow, and a heated airflow. 
     The fan assembly  1000  comprises a body or stand  1100  comprising an air inlet  1110  through which a primary airflow enters the body  1100 , at least one removable purifying/filter assembly  1200  mounted on the body  1100  over the air inlet  1110 , and a nozzle  1300  mounted on an air vent/opening  1115  through which the primary airflow exits the body  1100 . The nozzle  1300  comprises a first air outlet  1310  for emitting the primary airflow from the fan assembly  1000 , a second air outlet  1320  for emitting the primary airflow from the fan assembly  1000 , and a valve  1400  that is arranged to direct the primary airflow to one or both of the first air outlet  1310  and the second air outlet  1320  in dependence upon the position of a valve member  1410  of the valve  1400 . 
     The nozzle  1300  comprises an interior passage  1330  for conveying air from an air inlet  1340  of the nozzle  1300  to one or both of the first air outlet  1310  and the second air outlet  1320 . The nozzle  1300  also defines a central/inner opening/bore  1500  through which air from outside the fan assembly  1000  is drawn by the primary airflow emitted from the first outlet  1310  and which combines with the emitted airflow to produce an amplified airflow. The nozzle  1300  therefore forms a loop that extends around and surrounds the bore  1500 . 
     The second air outlet  1320  of the nozzle  1300  is arranged to receive the airflow from the interior passage  1330  and to emit the airflow without drawing air from outside the fan assembly through the opening/bore  1500  defined by the nozzle  1300 , thereby producing a non-amplified airflow. In the embodiments illustrated herein, the second air outlet  1320  is arranged to direct the emitted the airflow such that it substantially radiates/divaricates away from the fan assembly  1000 . In particular, the second air outlet  1320  is arranged to direct the non-amplified airflow such that it substantially radiates/divaricates away from a central axis (X) of the opening/bore  1500  defined by the nozzle  1300 , i.e. at an angle of between 30 degrees and 150 degrees away from the central axis (X) of the opening/bore  1500  defined by the nozzle  1300 . Preferably, the second air outlet  1320  is arranged to direct the non-amplified airflow substantially perpendicularly away from the central axis (X) of the opening/bore  1500  defined by the nozzle  1300 , i.e. at an angle from 45 to 135 degrees away from the central axis (X) of the opening/bore  1500  defined by the nozzle  1300 , and more preferably at an angle from 70 to 110 degrees from the central axis (X) of the opening/bore  1500  defined by the nozzle  1300 . The second air outlet  1320  would therefore be arranged to direct the non-amplified airflow in a direction that is substantially perpendicular to the direction in which air is drawn through the bore  1500 . 
       FIGS. 1 a  and 1 b    are external views of a first embodiment of a free-standing environmental control fan assembly  1000 , and  FIGS. 2 and 3  show sectional views through lines A-A and B-B of  FIGS. 1 a  and 1 b    respectively.  FIG. 4  then shows an enlarged sectional view of the body  1100  of the fan assembly  1000  illustrated in  FIGS. 1 a    and  1   b.    
     As shown in  FIGS. 2 and 4 , the body  1100  comprises a substantially cylindrical main body section  1120  mounted on a substantially cylindrical lower body section  1130 . The main body section  1120  has a smaller external diameter than the lower body section  1130 . The main body section  1120  has a lower annular flange  1121  that extends radially/perpendicularly away from the lower end of the main body section  1120 . The outer edge of the lower annular flange  1121  is substantially flush with the external surface of the lower body section  1130 . The removable purifying/filter assemblies  1200  are then mounted on the main body section  1120 , resting on the lower annular flange  1121  of the main body section  1120 . In this embodiment, the main body section  1120  further comprises an upper annular flange  1122  that extends radially/perpendicularly away from an opposite, upper end of the main body section  1120 . The outer edge of the upper annular flange  1122  is then substantially flush with the external surface of a base/neck  1350  of the nozzle  1300  that connects to upper end of the main body section  1120 . 
     In this first embodiment, the fan assembly  1000  comprises two separate purifying assemblies  1200   a ,  1200   b  that are configured to be located on and cover two opposing halves of the main body section  1120 . Each purifying assembly  1200  therefore substantially has the shape of a half cylinder/tube that can therefore be located concentrically over the main body section  1120 , resting on the lower annular flange  1121  of the main body section  1120 . Accordingly,  FIG. 5  shows the main body section  1120  with one of the purifying assemblies  1200   a  removed and with the other of the purifying assemblies  1200   b  mounted on the far side of the main body section  1120 . 
       FIG. 6 a    illustrates an exploded view of an embodiment of a filter assembly  1200  suitable for use with the fan assembly of  FIGS. 1 to 5 . In this embodiment, each filter assembly  1200  comprises a filter frame  13210  that supports one or more filter media. Each filter frame  1210  substantially has the shape of a semi-cylinder with two straight sides that are parallel to the longitudinal axis of the filter frame  1210  and two curved ends that are perpendicular to the longitudinal axis of the filter frame  1210 . The one or more filter media are arranged so as to cover the surface area defined by the filter frame  1210 . 
     The filter frame  1210  is provided with a first end flange  1211  that extends radially/perpendicularly away from a first curved end of the filter frame  1210  and a second end flange  1212  that extends radially/perpendicularly away from an opposite, second curved end of the filter frame  1210 . Each filter frame  1210  is then also provided with a first side flange  1213  that extends perpendicularly away from a first side of the filter frame  1210 , from a first end of the first end flange  1211  to a first end of the second end flange  1212 , and a second side flange  1214  that extends perpendicularly away from a second side of the filter frame  1210 , from a second end of the first end flange  1211  to a second end of the second end flange  1212 . The first end flange  1211 , second end flange  1212 , first side flange  1213  and second side flange  1214  are integrally formed with one another to thereby form a ridge or rim that extends around the entire periphery of the filter frame  1210 . The flanges  1211 - 1214  provide surfaces to which the filter media can be sealed (e.g. using glue on the downstream side of filter assembly  1210 ) and also provide surfaces that allow the filter frame  1210  to form a seal with the main body  1120  of the fan assembly  1000  (e.g. with corresponding flanges on the main body section  1120 ) to prevent air from leaking into or out of the fan body  1100  without passing through the filter media. 
     Each filter assembly  1200  further comprises a flexible seal  1230  provided around the entirety of an inner periphery of the filter frame  1210  for engaging with the main body section  1120  to prevent air from passing around the edges of the filter assembly  1200  to the air inlet  1110  of the main body section  1120 . The flexible filter seal  1230  preferably comprises lower and upper curved seal sections that substantially take the form of an arc-shaped wiper or lip seal, with the each end of the lower seal section being connected to a corresponding end of the upper seal section by two straight seal sections that each substantially take the form of a wiper or lip seal. The upper and lower curved seal sections are therefore arranged to contact the curved upper and lower ends of the main body section  1120 , whilst the straight seal sections are arranged to contact one or other of two diametrically opposed, longitudinal flanges extend perpendicularly away from the main body section  1120 . Preferably, the filter frame  1210  is provided with a recess (not shown) that extends around the entirety of the inner periphery of the filter frame  1210  and that is arranged to receive and support the seal  1230 . In the illustrated embodiment, this recess extends across an inner surface of both the first side flange  1213  and second side flange  1214 , and across an inner edge of both the first end and the second end of the filter frame  1210 . 
     One or more filter media  1221 ,  1222  are then supported on the outer, convex face of the filter frame  1210 , extending across the area between the first and second flanges  1211 ,  1212  and the first second side flanges  1213 ,  1214 . In the illustrated embodiment, each filter assembly  1200   a ,  1200   b  comprises a particulate filter media layer  1221  covered with an outer mesh layer  1222  attached on the outer face of the filter frame  1210 . Optionally, one or more further filter media can then be located within the inner, concave face of the filter frame  1210 . For example, these further filter media could comprise a first chemical filter media layer covered by a second chemical filter media layer that are both located within the inner face of the filter frame  1210 . These further filter media could either be attached to and/or support on the inner, concave face of the filter frame  1210  or alternatively could be mounted on to the main body section  1120 , resting on the lower annular flange  1111  of the main body section  1120  beneath each filter assembly  1200   a ,  1200   b . In either case, the filter frame  1210  will be formed so that it defines a space within the inner, concave face of the filter frame  1210  within which these further filter media can be accommodated when the filter assembly  1200  is mounted onto the main body section  1120 . 
     As shown in  FIG. 5 , a perforated shroud  1240  that is substantially in the shape of a half cylinder is then attached concentrically to the filter frame  1210  so as to cover the purifying assemblies  1200  when located on the main body section  1120 .  FIG. 6 b    illustrates a rear perspective view of a perforated shroud  1240  suitable for use with the fan assembly of  FIGS. 1 to 5 . The perforated shrouds  1240  each comprise an array of apertures which act as an air inlet  1241  of the purifying assembly  1200  in use of the fan  1000 . Alternatively, the air inlet  1241  of the shroud  1240  may comprise one or more grilles or meshes mounted within windows in the shroud  1240 . It will also be clear that alternative patterns of air inlet arrays are envisaged within the scope of the present invention. The shrouds  1240  protect the filter media  1221 - 1224  from damage, for example during transit, and also provides a visually appealing outer surface for the purifying assemblies  1200 , which is in keeping with the overall appearance of the fan assembly  1000 . As the shroud  1240  defines the air inlet  1241  for the purifying assembly  1200 , the array of apertures are sized to prevent larger particles from entering the purifying assembly  1200  and blocking, or otherwise damaging, the filter media  1221 - 1224 . 
     The main body section  1120  comprises a perforated housing  1124  that contains various components of the fan assembly  1000 . The perforated housing  1124  comprises the array of apertures which act as the air inlet  1110  of the body  1100  of the fan assembly  1000 . The purifying assemblies  1200  are then located upstream from the air inlets  1110  of the main body section  1120 , such that the air drawn into the main body section  1120  by the impeller  1150  is filtered prior to entering the main body section  1120 . This serves to remove any particles which could potentially cause damage to the fan assembly  1000 , and also ensures that the air emitted from the nozzle  1300  is free from particulates. In addition, this also serves to remove various chemical substances from that could potentially be a health hazard so that the air emitted from the nozzle  1300  is purified. In this embodiment the air inlets  1110  comprise an array of apertures formed in the main body section  1120 . Alternatively, the air inlets  1110  could comprise one or more grilles or meshes mounted within windows formed in the main body section  1120 . The main body section  1120  is open at the upper end thereof to accommodate the air vent/opening  1115  through which the primary airflow is exhausted from the body  1100 . 
     The lower body section  1130  comprises a further housing containing components of the fan assembly  1000  other than those contained within main body section  1120 . The lower body section  1130  is mounted on a base  1140  for engaging a surface on which the fan assembly  1000  is located. Specifically, the base  1140  supports the fan assembly  1000  when located on a surface with the nozzle  1300  uppermost relative to the base  1140 . In this embodiment, the lower body section  1130  houses a pan drive gear (not shown) that is engaged by a pan pinion (not shown). The pan pinion is driven by an oscillation motor  1160  housed within the bottom of the main body section  1120 . Rotation of the pan pinion by the oscillation motor  1160  therefore causes the main body section  1120  to rotate relative to the lower body section  1130 . A mains power cable (not shown) for supplying electrical power to the fan assembly  1000  extends through an aperture  1131  formed in the lower body section  1130 . The external end of the cable is then connected to a plug for connection to a mains power supply. 
     The main body section  1120  may be tilted relative to the lower body section  1130  to adjust the direction in which the primary airflow is emitted from the fan assembly  1000 . For example, the upper surface  1132  of the lower body section  1130  and the lower surface  1125  of the main body section  1120  may be provided with interconnecting features which allow the main body section  1120  to move relative to the lower body section  111  while preventing the main body section  110  from being lifted from the lower body section  1130 . For example, the lower body section  1130  and the main body section  1120  may comprise interlocking L-shaped members. In this embodiment, the upper surface  1132  of the lower body section  1130  is concave and the lower surface  1125  of the main body section  1120  is correspondingly convex. At least a portion of the two surfaces will therefore remain adjacent to one another, and the interconnecting features will remain at least partially connected, when the main body section  1120  is tilted relative to the lower body section  1130 . 
     As described above, the main body section  1120  houses the oscillation motor  1160  that drives the pan pinion that is engaged with the pan drive gear within the lower body section  1130 . In the embodiment illustrated in  FIGS. 3 and 5 , the oscillation motor  1160  is housed within the bottom of the main body section  1120 , adjacent to the convex lower surface  1125  of the main body section  1120 . Together the oscillation motor  126 , the pan pinion and the pan drive gear provide an oscillation mechanism for oscillating the main body section  1120  relative to the lower body section  1130 . This oscillation mechanism is controlled by a main control circuit  1170  of the fan assembly  1000  in response to control inputs provided by a user. 
     The mains power cable passes through the lower body section  1130  with the internal end of the mains power cable then being connected to a power supply unit  1180  housed towards the bottom of the main body section  1120 . In this embodiment, the power supply unit  1180  is mounted on a power supply mount  1181  that is fixed above the oscillation motor  1160 . A power supply cover  1182  is then positioned over the power supply unit  1180  to enclose and protect the power supply unit  1180 . In this embodiment, the power supply cover  1182  is substantially dome-shaped to minimize any disturbance of the primary airflow that enters the fan assembly  1000  through the air inlet  1110  and to assist in guiding primary airflow. Optionally, a heat sink (not shown) can be provided on the upper surface of the power supply cover  1182  to assist in dissipating heat generated by the power supply unit  1180 . Mounting the heat sink on the upper surface of the power supply cover  1182  locates the heat sink within the path of the primary airflow that enters the body  1100  through the air inlet  1110  such that the primary airflow will further assist in dissipating heat generated by the power supply unit  1180 . 
     The main body section  1120  houses the impeller  1150  for drawing the primary airflow through the air inlet  1110  and into the body  1100 . Preferably, the impeller  1150  is in the form of a mixed flow impeller. The impeller  1150  is connected to a rotary shaft  1151  extending outwardly from a motor  1152 . In the embodiment illustrated in  FIGS. 3 and 5 , the motor  1152  is a DC brushless motor having a speed which is variable by the main control circuit  1170  in response to control inputs provided by a user. The motor  1152  is housed within a motor bucket  1153  that comprises an upper portion  1153   a  connected to a lower portion  1153   b . The upper portion  1153   a  of the motor bucket further comprises a diffuser  1153   c  in the form of an annular disc having curved blades. 
     The motor bucket  1153  is located within, and mounted on, an impeller housing  1154  that is mounted within the main body section  1120 . The impeller housing  1154  comprises a generally frusto-conical impeller wall  1154   a  and an impeller shroud  1154   b  located within the impeller wall  1154   a . The impeller  1150 , impeller wall  1154   a  and an impeller shroud  1154   b  are shaped so that the impeller  1150  is in close proximity to, but does not contact, the inner surface of the impeller shroud  1154   b . A substantially annular inlet member  1155  is then connected to the bottom of the impeller housing  1154  for guiding the primary airflow into the impeller housing  1154 . 
     In the embodiment illustrated in  FIGS. 2 and 4 , the air vent/opening  1115  through which the primary airflow is exhausted from the body  1100  is defined by the upper portion of the motor bucket  1153   a  and the impeller wall  1154   a.    
     A flexible sealing member  1156  is attached between the impeller housing  1154  and the main body section  1120 . The flexible sealing member  1156  prevents air from passing around the outer surface of the impeller housing  1154  to the inlet member  1155 . The sealing member  1156  preferably comprises an annular lip seal, preferably formed from rubber. 
     As described above, the nozzle  1300  is mounted on the upper end of the main body section  1120  over the air vent  1115  through which the primary airflow exits the body  1100 . The nozzle  1300  comprises a neck/base  1350  that connects to upper end of the main body section  1120 , and has an open lower end which provides an air inlet  1340  for receiving the primary airflow from the body  1100 . The external surface of the base  1350  of the nozzle  1300  is then substantially flush with the outer edge of the upper annular flange  1121  of the main body section  1120 . The base  1350  therefore comprises a housing that covers/encloses any components of the fan assembly  1000  that are provided on the upper surface  1121  of the main body section  1120 . 
     In the embodiment illustrated in  FIGS. 3 and 5 , the main control circuit  1170  is mounted on the upper surface of the upper annular flange  1121  that extends radially away from the upper end of the main body section  1120 . The main control circuit  1170  is therefore housed within base  1350  of the nozzle  1300 . In addition, an electronic display  1180  is also mounted on the upper annular flange  1121  of the main body section  1120  and therefore housed within base  1350  of the nozzle  1300 , with the display  1180  being visible through an opening or at least partially transparent window provided in the base  1350 . Optionally, one or more additional electronic components may be mounted on the upper surface of the upper annular flange  1121  and consequentially housed within base  1350  of the nozzle  1300 . For example, these additional electronic components may one or more wireless communication modules, such as Wi-Fi, Bluetooth etc., and one or more sensors, such as an infrared sensor, a dust sensor etc., and any associated electronics. Any such additional electronic components would then also be connected to the main control circuit  1170 . 
     In the embodiment illustrated in  FIGS. 1 to 4 , the nozzle  1300  has an elongate annular shape, often referred to as a stadium shape, and defines an elongate opening  1500  having a height greater than its width. The nozzle  1300  therefore comprises two relatively straight sections  1301 ,  1302  each adjacent a respective elongate side of the opening  1500 , an upper curved section  1303  joining the upper ends of the straight sections  1301 ,  1302 , and a lower curved section  1304  joining the lower ends of the straight sections  1301 ,  1302 . 
     The nozzle  1300  therefore comprises an elongate annular outer casing section  1360  that is concentric with and extends about an elongate annular inner casing section  1370 . In this example, the inner casing section  1360  and the outer casing section  1370  are separate components; however, they could also be integrally formed as a single piece. The nozzle  1300  also has a curved rear casing section  1380  that forms the rear of the nozzle  1300 , with an inner end of the curved rear casing section  1380  being connected to a rear end of the inner casing section  1370 . In this example, the inner casing section  1370  and the curved rear casing section  1380  are separate components that are connected together, for example, using screws and/or adhesives; however, they could also be integrally formed as a single piece. The curved rear casing section  1380  has a generally elongate annular cross-section perpendicular to the central axis (X) of the inner bore  1500  of the nozzle  1300 , and a generally semi-circular cross-section parallel to the central axis (X) of the inner bore  1500  of the nozzle  1300 . 
     The inner casing section  1370  has a generally elongate annular cross-section perpendicular to the central axis (X) of the inner bore  1500  of the nozzle  1300 , and extends around and surrounds the inner bore  1500  of the nozzle  1300 . In this example, the inner casing section  1370  has a rear portion  1371  and a front portion  1372 . The rear portion  1371  is angled outwardly from the rear end of the inner casing section  1372  away from the central axis (X) of the inner bore  1500 . The front portion  1372  is also angled outwardly from the rear end of the inner casing section  1370  away from the central axis (X) of the inner bore  1500 , but with a greater angle of inclination than that of the rear portion  1371 . The front portion  1372  of the inner casing section  1370  therefore tapers towards the front end of the outer casing section  1360 , but does not meet the front end of the outer casing section  1360 , with the space between the front end of the inner casing section  1370  and the front end of the outer casing section  1360  defining a slot that forms a first air outlet  1310  of the nozzle  1300 . 
     The outer casing section  1360  then extends from the front of the nozzle  1300  towards an outer end of the curved rear casing section  1380 , but does not meet the outer end of the curved rear casing section  1380 , with the space between a rear end of the outer casing section  1360  and the outer end of the curved rear casing section  1380  defining a slot that forms a second air outlet  1320  of the nozzle  1300 . 
     The outer casing section  1360 , inner casing section  1370  and curved rear casing section  1380  therefore define an interior passage  1330  for conveying air from the air inlet  1340  of the nozzle  1300  to one or both of the first air outlet  1310  and the second air outlet  1320 . In other words, the interior passage  1330  is bounded by the internal surfaces of the outer casing section  1360 , inner casing section  1370  and curved rear casing section  1380 . The interior passage  1330  may be considered to comprise first and second sections which each extend in opposite directions about the bore  1500 , as the air that enters the nozzle  1300  through the air inlet  1340  will enter the lower curved section  1304  of the nozzle  1300  and be divided into two air streams which each flow into a respective one of the straight sections  1301 ,  1302  of the nozzle  1300 . 
     The nozzle  1300  further comprises two curved seal members  1365  each for forming a seal between the outer casing section  1360  and the inner casing section  1370  at the top and bottom curved sections  1303 ,  1304  of the nozzle  1300 , so that there is substantially no leakage of air from the curved sections of the interior passage  1330  of the nozzle  1300 . The nozzle  1300  therefore comprises two elongate first air outlets  1310   a ,  1310   b  each located on a respective elongate side of the central bore  1500 . In this embodiment, the nozzle  1300  is therefore provided with a pair of first air outlets  1310   a ,  1310   b  for emitting the primary airflow that are located on the opposite elongate sides of the nozzle  1300 /opening  1500  towards the front of the nozzle  1300 . 
     The nozzle  1300  then further comprises a pair of heater assemblies  1390   a ,  1390   b  within the interior passage  1330 , each heater assembly  1390   a ,  1390   b  being adjacent to a respective one of the pair of first air outlets  1310   a ,  1310   b . Each heater assembly  1390   a ,  1390   b  comprises a plurality of heater elements  1391  supported within a frame  1392 , with the frame  1392  then being mounted within the interior passage  1330  of the nozzle  1300  adjacent to the respective first air outlet  1310   a ,  1310   b . The frame  1392  of each heater assembly  1390   a ,  1390   b  is therefore arranged, when mounted within the interior passage  1330 , to direct the airflow through the heating elements  1391  and out of the corresponding first air outlet  1310   a ,  1310   b . To do so, the portion of the frame  1392  that is between the heater elements  1391  and the corresponding first air outlet  1310   a ,  1310   b  tapers towards the air outlet, with a narrow end of the frame  1392  being fitted within the corresponding first air outlet  1310   a ,  1310   b  provided in the forward facing edge of the nozzle  1300 . This tapered portion of the frame  1392  therefore acts as an airflow guide member as it funnels the primary airflow towards the first air outlet  1310   a ,  1310   b  and forms the duct  1311  of the first air outlet  1310   a ,  1310   b.    
     In the embodiment illustrated in  FIG. 4 , each of first air outlets  1310   a ,  1310   b  is therefore provided with a corresponding first airflow channel  1312   a ,  1312   b  within the interior passage  1330  of the nozzle  1300  that is defined by the frame  1392  of the corresponding heater assembly  1390 . The first airflow channels  1312   a ,  1312   b  are each arranged to direct the airflow towards the corresponding first air outlet  1310   a ,  1310   b . The air inlet into the first airflow channel  1312   a ,  1312   b , as defined by inner edge of the frame  1392  of the heater assembly  1390 , is substantially perpendicular to the central axis (X) of the bore/opening  1500 . 
     In order for the airflow emitted from the pair of first air outlets  1310   a ,  1310   b  to draw air from outside the fan assembly  1000  and combine with this air to produce an amplified airflow, the first air outlets  1310   a ,  1310   b  are arranged to direct the emitted the airflow in a direction that is substantially parallel to the central axis (X) of the opening/bore  1500  defined by the nozzle  1300 , i.e. at an angle from −30 to 30 degrees away from the central axis, preferably at an angle from −20 to 20 degrees away from the central axis, and more preferably at an angle from −10 to 10 degrees away from the central axis. To do so, the first air outlets  1310   a ,  1310   b  are arranged such that a duct  1311  of each first air outlet  1310   a ,  1310   b  is substantially parallel to the central axis (X) of the opening/bore  1500  defined by the nozzle  1300 . 
     The second air outlet  1320  is then arranged such that a duct  1321  of the second air outlet  1320  is substantially perpendicular relative to the central axis (X) of the opening/bore  1500  defined by the nozzle  1300 . As a consequence, the non-amplified airflow emitted from the second air outlet  1320  will be directed substantially perpendicularly away from the central axis (X) of the opening/bore  1500  defined by the nozzle  1300 . As illustrated in  FIG. 4 , the duct  1321  of the second air outlet  1320  extends from the interior passage  1330  that carries the primary airflow received from the body  1100  to the external periphery of the nozzle  1300  in a direction that is substantially perpendicular to the direction of the air drawn through the bore  1500 . 
     In the embodiment illustrated in  FIG. 4 , a baffle  1420  is provided within the interior passage that defines a second airflow channel  1322  within the interior passage  1330  that is arranged to direct the primary airflow towards the second air outlet  1320 . The baffle  1420  extends into the interior passage  1330  from an interior surface of the nozzle  1300  that at least partially defines the interior passage  1330 , with the second airflow channel  1322  being a section of the interior passage  1330  that is on one side of the baffle  1420 . In particular, the second airflow channel  1322  comprises a section of the interior passage  1330  that is bounded by the baffle  1420  and by a portion of the interior surface of the nozzle  1300  that is adjacent to the second air outlet  1320 . 
     The baffle  1420  is provided by a baffle wall that extends into the interior passage  1330  from the curved rear casing section  1380 . The baffle wall  1420  is connected to the outer end of the curved rear casing section  1380  and has a front portion  1421  and a rear portion  1422 . The rear portion  1422  of the baffle wall  1420  is angled inwardly from the outer end of the curved rear casing section  1380  towards the central axis (X) of the bore  1500 . The front portion  1421  is then angled relative to the rear portion  1422  so that the front portion  1421  is parallel to the outer casing section  1360 , with the majority of the front portion  1421  overlapping the outer casing section  1360 . The portion of the interior passage  1330  that is located between the front portion  1421  of the baffle wall  1420  and the overlapping portion of the outer casing section  360  therefore forms the second airflow channel  1322  within the interior passage  1330 , with the angled rear portion  1422  of the baffle wall  1420  providing the duct  1321  of the second air outlet  1320  that is substantially perpendicular relative to the central axis (X) of the opening/bore  1500  defined by the nozzle  1300 . The air inlet into the second airflow channel  1322 , as defined by front end of the baffle wall  1421  and the inner surface of the outer casing section  1360 , is substantially perpendicular to the central axis (X) of the opening/bore  1500  defined by the nozzle  1300 . 
     In the embodiment illustrated in  FIGS. 1 to 4 , the baffle wall  1420  extends up the elongate sides  1301 ,  1302  of the interior passage  1330  and around the upper curved section  1303 . The elongate sides of the baffle wall  1420  are generally straight; whilst the lower ends of the baffle wall  1420  extend only partially into the lower curved section  1304  until they meet the interior surface of the lower curved section  1304  of the interior passage  1330  so that the primary airflow cannot enter the second airflow channel  1322  via this lower end. A gasket  1423  provided on the front end of the baffle wall  1420  also extends around the lower edge of the baffle wall  1420  to improve the seal formed between the baffle wall  1420  and the interior surface of the lower curved section  1304  of the interior passage  1320 . 
     In addition, the baffle wall  1420  further comprises a projection  1424  at the peak/centre of upper curved section  1303  that extends from the outward facing surface of the baffle wall  1420  to the inner surface of the outer casing section  1360  thereby separating the adjacent portion of the second airflow channel  1322  from the interior passage  1330  and splitting the opening/inlet from the interior passage  1330  into the second airflow channel  1322  into two sections, each opening/inlet section extending up one of the elongate sides  1301 ,  1302  and partially around the upper curved section  1303  of the interior passage  1330  until they reach the projection  1424  at the peak of the upper curved section  1303 . 
     In the embodiment illustrated in  FIGS. 1 to 4 , the fan assembly  1000  then comprises a valve  1400  that is arranged to direct the primary airflow to one or both of the first air outlets  1310   a ,  1310   b  and the second air outlet  1320 . To do so, the valve  1400  comprises a pair of valve members  1410   a ,  1410   b  that are arranged to direct the primary airflow to one or both of the first air outlets  1310   a ,  1310   b  and the second air outlet  1320  in dependence upon the position of a pair of valve members  1410   a ,  1410   b . Each valve member  1410   a ,  1410   b  is therefore arranged to be moveable between a first end position in which the valve member directs the primary airflow to a corresponding one of pair of first air outlets  1310   a ,  1310   b  and prevents/obstructs the airflow from reaching the second air outlet  1320 , and a second end position in which the valve member directs the primary airflow to the second air outlet  1320  and prevents/obstructs the airflow from reaching the corresponding first air outlet  1310   a ,  1310   b . When the valve members  1410   a ,  1410   b  are located in-between the first end position and the second end position, the valve members direct a first portion of the primary airflow to the first air outlets  1310   a ,  1310   b  and a second portion of the primary airflow to the second air outlet  1320 . The closer the valve members  1410   a ,  1410   b  to the first end position the greater the proportion of the primary airflow that comprises the first portion that is directed to the to the first air outlets  1310   a ,  1310   b . Conversely, the closer the valve members  1410   a ,  1410   b  to the second end position the greater the proportion of the primary airflow that comprises the second portion that is directed to the to the second air outlet  1320 . 
     In the embodiment illustrated in  FIGS. 1 to 5 , the valve  1400  is provided within the interior passage  1330  of the nozzle  1300 . Consequently, each valve member  1410   a ,  1410   b  is arranged to close-off the second airflow channel  1322  from the remainder of the interior passage  1330  when in the first end position so as to substantially prevent the airflow from entering the second airflow channel  1322 , and to close-off a corresponding first airflow channel  1312   a ,  1312   b  from the remainder of the interior passage  1330  when in the second end position so as to substantially prevent the airflow from entering the first airflow channel  1312   a ,  1312   b.    
     Each valve member  1410   a ,  1410   b  is therefore arranged so that, in the first end position, the valve member  1410   a ,  1410   b  abuts/is seated against both the interior surface of the nozzle  1300  that is adjacent to the second air outlet  1320  and the baffle  1420  to thereby substantially close-off the corresponding inlet section of the second airflow channel  1322  from the remainder of the interior passage  1330 . The gasket  1423  provided on the front end of the baffle wall  1420  improves the seal formed between a valve member  1410   a ,  1410   b  and the baffle  1420  when the valve member  1410   a ,  1410   b  is in the first end position. Each valve member  1410   a ,  1410   b  is also arranged so that, in the second end position, the valve member  1410   a ,  1410   b  abuts/is seated against the inner periphery/edges of the frame  1392  of the corresponding heater assembly  1390  to thereby substantially close-off the corresponding first airflow channel  1312   a ,  1312   b  from the remainder of the interior passage  1330 , as illustrated in  FIG. 4 . The shape of each valve member  1410   a ,  1410   b  therefore substantially corresponds to/conforms with/correlates with that of the aligned section/portion of the interior passage  1330 . As shown in  FIG. 8 , which provides an exploded view of the nozzle  1300 , each valve member  1410   a ,  1410   b  is therefore generally J-shaped, having an elongate section and a curved end, and also has a generally J-shaped cross-section comprising an elongate section and a curved end. 
     In order to move the valve members  1410   a ,  1410   b  to any position from the first end position to the second end position the fan assembly  1000  is provided with a valve motor  1430  that is arranged to cause movement of the valve members  1410   a ,  1410   b  in response to signals received from the main control circuit  1170 . As shown in  FIG. 9 , the valve motor  1430  is arranged to rotate a pinion  1431  that engages with a curved or arc-shaped rack  1440 , with rotation of the valve motor  1430  causing rotation of both the pinion  1431  and the rack  1440 , and with the valve  1400  being configured such that rotation of the rack  1440  results in movement of the valve members  1410   a ,  1410   b.    
     In the embodiment illustrated in  FIGS. 1 to 9 , the valve motor  1430  is mounted on the baffle wall  1420  within the interior passage  1330  at the peak/centre of upper curved section  1303 , with the baffle wall  1420  then being attached to the rear casing section  1380 . A rotating shaft  1432  of the valve motor  1430  then projects towards the rear casing  1380 , with the axis of the rotation of the shaft  1432  being parallel to the centre axis (X) of the bore/opening  1500 . The pinion  1431  is mounted upon the rotating shaft  1432 , with the teeth of the pinion  1431  engaging the arc-shaped rack  1440  whose shape substantially corresponds to/conforms with/correlates with that of the upper curved section  1303  of the interior passage  1330 . 
     As the nozzle  1300  has an elongate annular shape, the rack  1440  has the shape of a minor arc wherein the rack  1440  subtends an angle that is less than 180 degrees. Specifically, the arc-shaped rack  1440  will extend around the majority of the upper curved section  1303  of the interior passage  1330  defined by the nozzle  1300 , with the ends of the arc-shaped rack  1440  each being aligned with the respective elongate sides  1301 ,  1302  of the interior passage  1330  when mounted within the nozzle  1300   
     As described above, the inlets into each of the first airflow channels  1312   a ,  1312   b  and the corresponding inlet sections of the second airflow channel  1322  are aligned with one another and are substantially parallel to the central axis (X) of the opening/bore  1500  of the nozzle  1300 . Consequently, in order for the valve members  1410   a ,  1410   b  to close off the second airflow channel  1322  when in the first end position and to close off the first airflow channels  1312   a ,  1312   b  when in the second end position, the valve members  1410   a ,  1410   b  are each arranged to move in a direction that is substantially parallel to the central axis (X) of the opening/bore  1500 . The valve  1400  is therefore configured such that the rotation of the rack  1440  is translated into movement of the valve members  1410   a ,  1410   b  in a direction that is parallel to the central axis (X) of the opening/bore  1500 . 
     In order to translate the rotation of the rack  1440  into movement of the valve members  1410   a ,  1410   b  in a direction that is parallel to the central axis (X) of the bore  1500 , the arc-shaped rack  1440  illustrated in  FIGS. 8 and 9  is provided with a pair of surfaces  1441   a ,  1441   b  that project from the rack  1440  in a direction that is parallel to the centre axis (X) of the bore  1500 , with each of these projecting surfaces  1441   a ,  1441   b  being curved so as to follow the curvature of the arc-shaped rack  1440 , and with the rack  1440  being configured such that the pair of surfaces  1441   a ,  1441   b  are located on opposite sides of the pinion  1431  when the pinion  1431  is engaged in the rack  1440 . Each of these projecting surfaces  1441   a ,  1441   b  is then provided with a linear cam in the form of a cam slot  1442   a ,  1442   b  that extends across the curved surface at an angle of approximately 45 degrees relative to the axis of the rotation of the rack  1440 , and that is arranged to be engaged by a follower pin  1411   a ,  1411   b  that projects from the corresponding valve member  1410   a ,  1410   b , with the cam slots  1442   a ,  1442   b  provided on both of the projecting surfaces being angled in the same direction. 
     In addition, a first of a pair of valve actuators  1450   a  is rotatably connected/attached to a first end of the arc-shaped rack  1440  and a second of the pair of valve actuators  1450   b  is rotatably connected/attached to an opposite, second end of the arc-shaped rack  1440 . Each valve actuator  1450   a ,  1450   b  is elongate (being arranged to extend along the elongate sides  1301 ,  1302  of the interior passage  1330 ) and is provided with an upper cam slot  1451  provided towards the upper end of the valve actuator  1450   a ,  1450   b  and a lower cam slot  1452  provided towards the lower end of the valve actuator  1450   a ,  1450   b . The upper and lower cam slots  1451 ,  1452  extend across the corresponding valve actuator  1450   a ,  1450   b  at an angle of approximately 45 degrees relative to the centre axis (X) of the bore  1500  and are each arranged to be engaged by a follower pin  1412 ,  1413  that projects from the corresponding valve member  1410   a ,  1410   b . The cam slots  1451   a ,  1452   a  on a first of the valve actuators  1450   a  are angled upwards as the cam slots extend from the back to the front of the valve actuator  1450   a , whereas the cam slots  1451   b ,  1452   b  on a second of the valve actuators  1450   b  are angled downwards as the cam slots extend from the back to the front of the valve actuator  1450   b.    
     Each valve member  1410   a ,  1410   b  therefore comprises three follower pins  1411 ,  1412 ,  1413  that are arranged to engage with the cam slot  1442  provided on the corresponding portion of the rack  1440  and the upper and lower cam slots  1451 ,  1452  provided on the corresponding valve actuator  1450   a ,  1450   b  respectively. 
     In order to move the valve members  1410   a ,  1410   b  to any position from the first end position to the second end position, the main control circuit  1170  sends a signal to the valve motor  1430  that causes the motor to rotate the shaft  1432  in one direction or the other, thereby causing rotation of the pinion  1431  provided on the shaft  1432 . Engagement of the pinion  1431  with the arc-shaped rack  1440  therefore causes the rack  1440  to rotate in the same direction as the shaft  1432 . Rotation of the arc-shaped rack  1440  therefore causes the angled cam slots  1442  provided on the curved surfaces  1441   a ,  1441   b  that project from the rack  1440  to move relative to the follower pin  1411  of the corresponding valve member  1410   a ,  1410   b  that is engaged within the cam slot, with the angle of the cam slots  1442   a ,  1442   b  translating the rotational movement of the arc-shaped rack  1440  into linear movement of the valve members  1410   a ,  1410   b  in a direction that is parallel to the centre axis (X) of the bore  1500 . In particular, rotation of the arc-shaped rack  1440  will cause both the projecting surfaces  1441   a ,  1441   b  to rotate in the same direction. In this regard, as the cam slots  1442   a ,  1442   b  provided on the curved surfaces  1441   a ,  1441   b  that project from the rack  1440  are angled in the same direction, rotation of the curved surfaces  1441   a ,  1441   b  in the same direction is translated into horizontal movement of the first valve member  1410   a  and second valve member  1410   b  in the same direction. 
     In addition, rotation of the arc-shaped rack  1440  results in vertical displacement of the first and second ends of the arc-shaped rack  1440  that in-turn causes vertical displacement of the valve actuators  1450   a ,  1450   b  that are rotatably connected to the ends of the arc-shaped rack  1440 . In particular, rotation of the arc-shaped rack  1440  will cause upwards movement of one of the first and second ends of the arc-shaped rack  1440  and the connected valve actuator  1450   a ,  1450   b , and downwards movement of the other of the first and second ends of the arc-shaped rack  1440  and the connected valve actuator  1450   a ,  1450   b . Vertical displacement of the valve actuators  1450   a ,  1450   b  causes the angled cam slots  1451 ,  1452  provided on the valve actuators  1450   a ,  1450   b  to move relative to the respective follower pins  1412 ,  1413  of the corresponding valve member  1410   a ,  1410   b , with the angle of the cam slot  1451 ,  1452  translating the vertical displacement of the valve actuators  1450   a ,  1450   b  into horizontal movement of the valve members  1410   a ,  1410   b  in a direction that is parallel to the centre axis (X) of the bore  1500 . In this regard, as the cam slots  1451   a ,  1452   a  provided on the first valve actuator  1450   a  are angled in the opposite direction to those provided on the second valve actuator  1450   b , movement of the first valve actuator  1450   a  and the second valve actuator  1450   b  in opposing vertical directions is translated into horizontal movement of the first valve member  1410   a  and second valve member  1410   b  in the same direction. 
     To operate the fan assembly  1000  the user presses button on a user interface. The user interface may be provided on the fan assembly  1000  itself, on an associated remote control (not shown), and/or on a wireless computing device such as a tablet or smartphone (not shown) that communicates with the fan assembly  1000  wirelessly. This action by the user is communicated to the main control circuit  1170 , in response to which the main control circuit  1170  activates the fan motor  1152  to rotate the impeller  1150 . The rotation of the impeller  1150  causes a primary airflow to be drawn into the body  1100  through the air inlet  1110  via the purifying assemblies  1200 . The user may control the speed of the fan motor  1152 , and therefore the rate at which air is drawn into the body  1100  through the air inlet  1110 , by manipulating the user interface. The primary airflow passes sequentially through the purifying assemblies  1200 , air inlet  1110 , the impeller housing  1154  and the air vent  1115  at the open upper end of the main body section  1120  to enter the interior passage  1330  of the nozzle  1300  via the air inlet  1340  located in the base  1350  of the nozzle  1300 . 
     Within the interior passage  1330 , the primary airflow is divided into two air streams which pass in opposite angular directions around the bore  1500  of the nozzle  1300 , each within a respective straight section  1301 ,  1302  of the interior passage  1330 . As the air streams pass through the interior passage  1330 , air is emitted through one or both of the first air outlets  1310   a ,  1310   b  and the second air outlet  320  in dependence upon the position of the valve members  1410   a ,  1410   b  of the valve  1400 . 
     In the embodiment illustrated in  FIGS. 1 to 9 , when both of the valve members  1410   a ,  1410   b  provided in the interior passage  1330  are in the first end position, the elongate section of the generally J-shaped cross-section of the valve members  1410   a ,  1410   b  will be in contact with the gasket  1423  provided on the front end of the baffle wall  1420 , whilst the curved end of the generally J-shaped cross-section of the valve member  1410   a ,  1410   b  will be in contact with the overlapping portion of the inner surface of the outer casing section  1360 . The valve members  1410   a ,  1410   b  will therefore substantially close-off the inlets into the second airflow channel  1322  from the remainder of the interior passage  1330  so as to substantially prevent the airflow from entering the second airflow channel  1322 , and will therefore direct the entirety primary airflow to the first air outlets  1310   a ,  1310   b . When both of the valve members  1410   a ,  1410   b  provided in the interior passage  1330  are in the second end position, the elongate section of the generally J-shaped cross-section of the valve members  1410   a ,  1410   b  will be in contact with the inner periphery/edges of the frame  1392  of the corresponding heater assembly  1390   a ,  1390   b . The valve members  1410   a ,  1410   b  will therefore substantially close-off the first airflow channels  1312   a ,  1312   b  from the remainder of the interior passage  1330 , and will therefore direct the entirety primary airflow to the second air outlet  1320 . When both of the valve members  1410   a ,  1410   b  are located in-between the first end position and the second end position, then both the first airflow channels  1312   a ,  1312   b  and the second airflow channel  1322  will be open to the remainder of the interior passage  1330 , with a first portion of the primary airflow being directed to the first air outlets  1310   a ,  1310   b  and a second portion of the primary airflow being directed to the second air outlet  1320 . 
     The emission of the primary airflow or a portion of the primary airflow from the first air outlets  1310   a ,  1310   b  in a direction that is substantially parallel to a central axis (X) of the opening/bore  1500  defined by the nozzle  1300  causes a secondary airflow to be generated by the entrainment of air from the external environment, specifically from the region around the nozzle  1300 . This secondary airflow combines with the primary airflow emitted from the first air outlets  1310   a ,  1310   b  to produce a combined, amplified airflow that is projected forward from the nozzle  1300 . In contrast, emission of the primary airflow from the second air outlet  1320  such that the primary airflow substantially radiates/divaricates away from the fan assembly  1000  prevents this airflow from drawing air from outside the fan assembly  1000  through the opening/bore  1500  defined by the nozzle  1300 , thereby producing a non-amplified airflow. 
       FIGS. 10 and 11  are external views of a nozzle  1300  of a second embodiment of a free-standing environmental control fan assembly  1000 , and  FIGS. 12 a  and 12 b    show sectional views through line A-A of  FIG. 11 . In this second embodiment, the body  1100  of fan assembly  1000  is substantially the same as that of the first embodiment and has therefore not been further illustrated nor described. In addition, the nozzle  1300  of this second embodiment is also substantially the same as that of the first embodiment and corresponding reference numerals have therefore been used for like or corresponding parts or features of these embodiments. 
     In this second embodiment, the nozzle  1300  is mounted on the upper end of the main body section  1120  over the air vent  1115  through which the primary airflow exits the body  1100 . As with the first embodiment, the nozzle  1300  comprises a neck/base  1350  that connects to upper end of the main body section  1120 , and has an open lower end which provides an air inlet  1340  for receiving the primary airflow from the body  1100 . The external surface of the base  1350  of the nozzle  1300  is then substantially flush with the outer edge of the upper annular flange  1121  of the main body section  1120 . 
     The only significant difference between the first embodiment and the second embodiment is that the second embodiment does not include heater assemblies  1390   a ,  1390   b  within the interior passage  1330  adjacent to the first air outlets  1310   a ,  1310   b . As a consequence, the fan assembly  1000  of the second embodiment does not include the frames of the heater assemblies  1392   a ,  1392   b  that funnel the primary airflow towards the first air outlets  1310   a ,  1310   b  and that therefore defines first airflow channels  1312   a ,  1312   b  within the interior passage  1330  of the nozzle  1300 . In contrast, the fan assembly  1000  of the second embodiment comprises one or more airflow guide members  1331   a ,  1331   b  that are arranged, when mounted within the interior passage  1330 , to direct the airflow out of the corresponding first air outlet  1310   a ,  1310   b.    
     To do so, each airflow guide member  1331   a ,  1331   b  comprises a front end that is fitted within the corresponding first air outlet  1310   a ,  1310   b  provided in the forward facing edge of the nozzle  1300 , and that therefore forms the duct  1311  of the first air outlet  1310   a ,  1310   b , and with a rear surface that is angled relative to the front end. This angled rear surface of the each airflow guide member  1331   a ,  1331   b  therefore funnels the primary airflow towards the corresponding first air outlet  1310   a ,  1310   b  and the duct  1311  of the first air outlet  1310   a ,  1310   b  that is provided by the front end of the airflow guide member  1331   a ,  1331   b . The first airflow channels  1312   a ,  1312   b  within the interior passage  1330  of the nozzle  1300  are therefore at least partially defined by a respective airflow guide member  1331   a ,  1331   b . The valve  1400  is therefore arranged so that, in the second end position, the valve members  1410   a ,  1410   b  abut/are seated against the angled surface of the corresponding airflow guide member  1331   a ,  1331   b  and against a surface of the corresponding valve actuator  1450   a ,  1450   b , the valve actuator  1450   a ,  1450   b  being located within the interior passage  1330  adjacent to the inner surface of the outer casing  1360 , to thereby substantially close-off the first airflow channel  1312   a ,  1312   b  from the remainder of the interior passage  1330 , as illustrated in  FIG. 12 a   . In addition, the valve  1400  is arranged so that, in the first end position, the valve members  1410   a ,  1410   b  abut/are seated against both the front end of the baffle wall  1420  and against the surface of the corresponding valve actuator  1450   a ,  1450   b  that is adjacent to the second air outlet  1320  to thereby substantially close-off the second airflow channel  1322  from the remainder of the interior passage  1330 , as illustrated in  FIG. 12   b.    
     Another difference between the first embodiment and the second embodiment is that in the second embodiment the arc-shaped rack  1440  is not provided with a pair of surfaces  1441   a ,  1441   b  that project from the rack  1440  in a direction that is parallel to the centre axis (X) of the bore  1500 . As illustrated in  FIGS. 13 and 14 , in the second embodiment the arc-shaped rack  1440  is provided with a single surface  1441  that projects from the rack  1440  in a direction that is parallel to the centre axis (X) of the bore  1500 , and that extends along the length of the arc-shaped rack  1440 . This projecting surface  1441  is then provided with two linear cams, each in the form of a cam slot  1442   a ,  1442   b  that extends across the curved surface at an angle of approximately 45 degrees relative to the axis of the rotation of the rack  1440 , and with the rack  1440  being configured such the cam slots  1442   a ,  1442   b  are located on opposite sides of the pinion  1431  when the pinion  1431  is engaged in the rack  1440 . The cam slots  1442   a ,  1442   b  are each arranged to be engaged by a follower pin  1411   a ,  1411   b  that projects from the corresponding valve member  1410   a ,  1410   b , with the cam slots  1442   a ,  1442   b  being angled in the same direction. 
     A first of a pair of valve actuators  1450   a  is rotatably connected/attached to a first end of the arc-shaped rack  1440  and a second of the pair of valve actuators  1450   b  is rotatably connected/attached to an opposite, second end of the arc-shaped rack  1440 . Each valve actuator  1450   a ,  1450   b  is elongate (being arranged to extend along the elongate sides  1301 ,  1302  of the interior passage  1330 ) and is provided with an upper cam slot  1451  provided towards the upper end of the valve actuator  1450   a ,  1450   b , a lower cam slot  1452  provided towards the lower end of the valve actuator  1450   a ,  1450   b , and a middle cam slot  1453  provided towards the middle of the valve actuator  1450   a ,  1450   b . The upper, lower and middle cam slots  1451 ,  1452 ,  1453  extend across the corresponding valve actuator  1450   a ,  1450   b  at an angle of approximately 45 degrees relative to the centre axis (X) of the bore  1500  and are each arranged to be engaged by a follower pin  1412 ,  1413 ,  1414  that projects from the corresponding valve member  1410   a ,  1410   b . The cam slots  1451   a ,  1452   a ,  1453   a  on a first of the valve actuators  1450   a  are angled upwards as the cam slots extend from the back to the front of the valve actuator  1450   a , whereas the cam slots  1451   b ,  1452   b ,  1453   b  on a second of the valve actuators  1450   b  are angled downwards as the cam slots extend from the back to the front of the valve actuator  1450   b.    
     Each valve member  1410   a ,  1410   b  therefore comprises four follower pins  1411 ,  1412 ,  1413 ,  1414  that are arranged to engage with the cam slot  1442  provided on the corresponding portion of the rack  1440  and the upper, lower and middle cam slots  1451 ,  1452 ,  1453  provided on the corresponding valve actuator  1450   a ,  1450   b  respectively. 
     The operation of the valve, including the movement of the valve members  1450   a ,  1450   b , of the second embodiment is implemented in substantially the same way as that described above for the first embodiment and has therefore not been further described. 
       FIGS. 15 and 16  are external views of a nozzle  2300  of a third embodiment of a free-standing environmental control fan assembly  1000 , and  FIGS. 17 a  and 17 b    show sectional views through line A-A of  FIG. 15 . In this third embodiment, the body  1100  of fan assembly  1000  is substantially the same as that of the first and second embodiments and has therefore not been further illustrated nor described. However, rather than having an elongate annular shape, the nozzle  2300  of this third embodiment is annular/generally cylindrical in shape such that there are differences in the construction of the nozzle  2300  and also differences in the valve  2400  provided within the interior passage  2330  of the nozzle  2300 . 
     In this third embodiment, the nozzle  2300  is mounted on the upper end of the main body section  1120  over the air vent  1115  through which the primary airflow exits the body  1100 . The nozzle  2300  comprises a neck/base  2350  that connects to upper end of the main body section  1120 , and has an open lower end which provides an air inlet  2340  for receiving the primary airflow from the body  1100 . The external surface of the base  2350  of the nozzle  1300  is then substantially flush with the outer edge of the upper annular flange  1121  of the main body section  1120 . 
     In the embodiment illustrated in  FIGS. 15 to 19 , the nozzle  2300  comprises an annular/cylindrical outer casing section  2360  that is concentric with and extends about an annular/generally cylindrical inner casing section  2370 . In this example, the inner casing section  2370  and the outer casing section  2360  are separate components; however, they could also be integrally formed as a single piece. The nozzle  2300  also has a curved rear casing section  2380  that forms the rear of the nozzle  2300 , with an inner end of the curved rear casing section  2380  being connected to a rear end of the inner casing section  2370 . In this example, the inner casing section  2370  and the curved rear casing section  2380  are separate components that are connected together, for example, using screws and/or adhesives; however, they could also be integrally formed as a single piece. The curved rear casing section  2380  has a generally annular/cylindrical cross-section perpendicular to the central axis (X) of the inner bore  2500  of the nozzle  2300 , and a generally semi-circular cross-section parallel to the central axis (X) of the inner bore  2500  of the nozzle  2300 . 
     The inner casing section  2370  has a generally annular/cylindrical cross-section perpendicular to the central axis (X) of the inner bore  2500  of the nozzle  2300 , and extends around and surrounds the inner bore  2500  of the nozzle  2300 . In this example, the inner casing section  2370  has a rear portion  2371  and a front portion  2372 . The rear portion  2371  is angled outwardly from the rear end of the inner casing section  2370  away from the central axis (X) of the inner bore  2500 . The front portion  2372  is also angled outwardly from the rear end of the inner casing section  2370  away from the central axis (X) of the inner bore  2500 , but with a greater angle of inclination than that of the rear portion  2371 . The front portion  2372  of the inner casing section  2370  therefore tapers towards the front end of the outer casing section  2360 , but does not meet the front end of the outer casing section  2360 , with the space between the front end of the inner casing section  2370  and the front end of the outer casing section  2360  defining a slot that forms a first air outlet  2310  of the nozzle  2300 . 
     The outer casing section  2360  then extends from the front of the nozzle  2300  towards an outer end of the curved rear casing section  2380 , but does not meet the outer end of the curved rear casing section  2380 , with the space between a rear end of the outer casing section  2360  and the outer end of the curved rear casing section  2380  defining a slot that forms a second air outlet  2320  of the nozzle  2300 . 
     The outer casing section  2360 , inner casing section  2370  and curved rear casing section  2380  therefore define an interior passage  2330  for conveying air from an air inlet  2340  of the nozzle  2300  to one or both of the first air outlet  2310  and the second air outlet  2320 . In other words, the interior passage  2330  is bounded by the internal surfaces of the outer casing section  2360 , inner casing section  2370  and curved rear casing section  2380 . The interior passage  2330  may be considered to comprise first and second sections which each extend in opposite directions about the bore  2500 , as the air that enters the nozzle  2300  through the air inlet  2340  will enter the nozzle  2300  and be divided into two air streams which each flow in opposite directions around the interior passage  2330  of the nozzle  2300 . 
     As described above, the first air outlet  2310  takes the form of a slot provided by the space between the front end of the inner casing section  2370  and the front end of the outer casing section  2360 . The nozzle  2300  therefore comprises a single first air outlet  2310  that is provided in the forward facing edge of the nozzle  2300  and extends around the majority of the periphery of the central bore  2500  for emitting the primary airflow towards the front of the nozzle  2300 . 
     In order for the airflow emitted from the first air outlet  2310  to draw air from outside the fan assembly  1000  and combine with this air to produce an amplified airflow, the first air outlet  2310  is arranged to direct the emitted the airflow in a direction that is substantially parallel to the central axis (X) of the opening/bore  2500  defined by the nozzle  2300 , i.e. at an angle from −30 to 30 degrees away from the central axis, preferably at an angle from −20 to 20 degrees away from the central axis, and more preferably at an angle from −10 to 10 degrees away from the central axis. To do so, the first air outlet  2310  is arranged such that a duct  2311  of the first air outlet  2310  is substantially parallel to the central axis (X) of the opening/bore  2500  defined by the nozzle  2300 . The inner casing section  2370  is therefore provided with a projection  2373  that extends inwardly into the interior passage  2330  of the nozzle  2300  from the front end of the inner casing section  2370  that is immediately adjacent to space between the front end of the inner casing section  2370  and the front end of the outer casing section  2360 . This inwardly extending projection  2373  together with the opposing inner surface of the outer casing section  2360  therefore defines the duct  2311  of the first air outlet  2310  that is substantially parallel to the central axis (X) of the bore/opening  2500 . An airflow guide member  2331  is then provided within the interior passage  2330  that extends from the inner end of the inwardly extending projection  2373  to an adjacent portion of the inner surface of the inner casing section  2370 . This airflow guide member  2331  therefore assist in directing the primary airflow towards the first air outlet  2310  and the duct  2311  of the first air outlet  2310  that is partially defined by the inwardly extending projection  2373 . A first airflow channel  2312  within the interior passage  2330  of the nozzle  2300  is therefore at least partially defined by the airflow guide member  2331 . 
     The second air outlet  2320  is then arranged such that a duct  2321  of the second air outlet  2320  is substantially perpendicular relative to the central axis (X) of the opening/bore  2500  defined by the nozzle  2300 . As a consequence, the non-amplified airflow emitted from the second air outlet  2320  will be directed substantially perpendicularly away from the central axis (X) of the opening/bore  2500  defined by the nozzle  2300 . As illustrated in  FIGS. 17 a  and 17 b   , the duct  2321  of the second air outlet  2320  extends from the interior passage  2330  that carries the primary airflow received from the body  1100  to the external periphery of the nozzle  2300  in a direction that is substantially perpendicular to the direction of the air drawn through the bore  2500 . 
     In the embodiment illustrated in  FIGS. 17 a  and 17 b   , a baffle  2420  is provided within the interior passage that defines a second airflow channel  2322  within the interior passage  2330  that is arranged to direct the primary airflow towards the second air outlet  23200 . The baffle  2420  extends into the interior passage  2330  from an interior surface of the nozzle  2300  that at least partially defines the interior passage  2330 , with the second airflow channel  2322  being a section of the interior passage  2330  that is on one side of the baffle  2420 . In particular, the second airflow channel  2332  comprises a section of the interior passage  2330  that is bounded by the baffle  2420  and by a portion of the interior surface of the nozzle  2300  that is adjacent to the second air outlet  2320 . 
     The baffle  2420  is provided by a baffle wall that extends into the interior passage  2330  from the curved rear casing section  2380 . The baffle wall  2420  is connected to the outer end of the curved rear casing section  2380  and has a front portion  2421  and a rear portion  2422 . The rear portion  2422  of the baffle wall  2420  is angled inwardly from the outer end of the curved rear casing section  2380  towards the central axis (X) of the bore  2500 . The front portion  2421  is then angled relative to the rear portion  2422  so that the front portion  2421  is parallel to the outer casing section  2360 , with the majority of the front portion  2421  overlapping the outer casing section  2360 . The portion of the interior passage  2330  that is located between the front portion  2421  of the baffle wall  2420  and the overlapping portion of the outer casing section  2360  therefore forms the second airflow channel  2322  within the interior passage  2330 , with the angled rear portion  2422  of the baffle wall  2420  providing the duct  2321  of the second air outlet  2320  that is substantially perpendicular relative to the central axis (X) of the opening/bore  2500  defined by the nozzle  2300 . The air inlet into the second airflow channel  2322 , as defined by front end of the baffle wall  2420  and the inner surface of the outer casing section  2360 , is substantially parallel to the central axis (X) of the opening/bore  2500  defined by the nozzle  2300 . 
     In the embodiment illustrated in  FIGS. 17 a  and 17 b   , the baffle wall  2420  extends around the majority of the interior passage  2330 . The lower ends of the baffle wall  2420  are angled away from the central axis (X) of the opening/bore  2500  so that they meet the interior surface of the lower section of the interior passage  2330  so that the primary airflow cannot enter the second airflow channel  2322  via this lower end. 
     In this third embodiment, the nozzle  2300  comprises a valve  2400  that is arranged to direct the primary airflow to one or both of the first air outlet  2310  and the second air outlet  2320 . To do so, the valve  2400  comprises a single valve member  2410  that is arranged to direct the primary airflow to one or both of the first air outlet  2310  and the second air outlet  2320  in dependence upon the position of the valve member  2410 . The valve member  2410  is therefore arranged to be moveable between a first end position in which the valve member  2410  directs the primary airflow to the first air outlet  2310  and prevents/obstructs the airflow from reaching the second air outlet  2320 , and a second end position in which the valve member  2410  directs the primary airflow to the second air outlet  2320  and prevents/obstructs the airflow from reaching the first air outlet  2310 . When the valve member  2410  is located in-between the first end position and the second end position, the valve member  2410  directs a first portion of the primary airflow to the first air outlet  2310  and a second portion of the primary airflow to the second air outlet  2320 . The closer the valve member  2410  to the first end position the greater the proportion of the primary airflow that comprises the first portion that is directed to the to the first air outlet  2310 . Conversely, the closer the valve member  2410  to the second end position the greater the proportion of the primary airflow that comprises the second portion that is directed to the to the second air outlet  2320 . 
     In this third embodiment, the valve  2400  is provided within the interior passage  2330  of the nozzle  2300 . Consequently, the valve member  2410  is arranged to close-off the second airflow channel  2322  from the remainder of the interior passage  2330  when in the first end position so as to substantially prevent the airflow from entering the second airflow channel  2322 , and to close-off a first airflow channel  2312  from the remainder of the interior passage  2330  when in the second end position so as to substantially prevent the airflow from entering the first airflow channel  2312 . 
     In order to move the valve member  2410  to any position from the first end position to the second end position the fan assembly  1000  is provided with a valve motor  2430  that is arranged to cause movement of the valve member  2410  in response to signals received from the main control circuit  1170 . As shown in  FIG. 18 , the valve motor  2430  is arranged to rotate a pinion  2431  that engages with an arc-shaped rack  2440 , with rotation of the valve motor  2430  causing rotation of both the pinion  2431  and the rack  2440 , and with the valve  2400  being configured such that rotation of the rack  2440  results in movement of the valve member  2410 . 
     The valve motor  2430  is mounted on the baffle wall  2420  within the interior passage  2330  at the peak/top of the interior passage  2330 , with the baffle wall  2420  then being attached to the rear casing section  2380 . A rotating shaft  2432  of the valve motor  2430  then projects towards the rear casing  2380 , with the axis of the rotation of the shaft  2432  being parallel to the centre axis (X) of the bore/opening  2500 . The pinion  2431  is mounted upon the rotating shaft  2432 , with the teeth of the pinion  2431  engaging the arc-shaped rack  2440  whose shape substantially corresponds to/conforms with/correlates with that of the interior passage  2330  of the annular/cylindrical nozzle  2300 . 
     As the nozzle  2300  is annular/cylindrical in shape, the rack  2440  has the shape of a major arc wherein the rack  2440  subtends an angle that is greater than 180 degrees. Specifically, the arc-shaped rack  2440  will extend around the majority of the interior passage  2330  defined by the nozzle  2300 , with the space between the ends of the arc-shaped rack  2440  being aligned with the air inlet  2340  when mounted within the interior passage  2330  of the nozzle  2300   
     The inlet into the first airflow channel  2312  and the inlet of the second airflow channel  2322  are aligned with one another and are substantially parallel to the central axis (X) of the opening/bore  2500  of the nozzle  2300 . Consequently, in order for the valve member  2410  to close off the second airflow channel  2322  when in the first end position and to close off the first airflow channel  2312  when in the second end position, the valve member  2410  is each arranged to move in a direction that is substantially parallel to the central axis (X) of the opening/bore  2500 . The valve  2400  is therefore configured such that the rotation of the rack  2440  is translated into movement of the valve member  2410  in a direction that is parallel to the central axis (X) of the opening/bore  2500 . 
     In order to translate the rotation of the rack  2440  into movement of the valve member  2410  in a direction that is parallel to the central axis (X) of the bore  2500 , the arc-shaped rack  2440  illustrated in  FIGS. 18 and 19  is provided with a single surface  2441  that projects from the rack  2440  in a direction that is parallel to the centre axis (X) of the bore  2500 , and that extends along the length of the arc-shaped rack  2440 . The projecting surface  2441  is then provided with five linear cams distributed evenly around the length of the arc-shaped rack  2440 , each linear cam being in the form of a cam slot  2442   a - e  that extends across the curved surface at an angle of approximately 45 degrees relative to the axis of the rotation of the rack  2440 . In this third embodiment, the rack  2440  is configured such that one of the five the cam slots  2242   a  is located at the mid-point along the length of the rack  2440 , adjacent to the location at which the pinion  2431  engages in the rack  2440  and opposite to the air inlet  2340 . The four further cam slots  2442   b ,  2442   c ,  2442   d ,  2442   e  are then distributed on either side of the middle cam slot  2442   a  such that two of these cam slots are located on each half of the rack  2440 , such that there are two slots located either side of the pinion  2431  when the pinion  2431  is engaged in the rack  2440 . The cam slots  2442   a - e  are each arranged to be engaged by a corresponding follower pin  2411   a - e  that projects from the valve member  2410 , with all of the cam slots  2442   a - e  being angled in the same direction. 
     In order to move the valve member  2410  to any position from the first end position to the second end position, the main control circuit  1170  sends a signal to the valve motor  2430  that causes the motor to rotate the shaft  2432  in one direction or the other, thereby causing rotation of the pinion  2431  provided on the shaft  2432 . Engagement of the pinion  2431  with the arc-shaped rack  2440  therefore causes the rack  2440  to rotate in the same direction as the shaft  2432 . Rotation of the arc-shaped rack  2440  therefore causes the angled cam slots  2442   a - e  provided on the curved surface  2441  of the rack  2440  to move relative to the corresponding follower pins  2411   a - e  of the valve member  2410 , with the angle of the cam slots  2442   a - e  translating the rotational movement of the arc-shaped rack  2440  into linear movement of the valve member  2410  in a direction that is parallel to the centre axis (X) of the bore  2500 . 
     The valve  2400  is therefore arranged so that, in the second end position, the valve member  2410  abuts/is seated against the surface of the airflow guide member  2331  and against a surface of the arc-shaped rack  2440  that is located within the interior passage  2330  adjacent to the inner surface of the outer casing  2360 , to thereby substantially close-off the first airflow channel  2312  from the remainder of the interior passage  2330 , as illustrated in  FIG. 17 a   . In addition, the valve  2400  is arranged so that, in the first end position, the valve member  2410  abuts/is seated against both the front end of the baffle wall  2420  and against the surface of the arc-shaped rack  2440  that is adjacent to the second air outlet  2320  to thereby substantially close-off the second airflow channel  2322  from the remainder of the interior passage  2330 , as illustrated in  FIG. 17   b.    
     When the valve member  2410  is located in-between the first end position and the second end position, the valve member  2410  directs a first portion of the primary airflow to the first air outlet  2310  and a second portion of the primary airflow to the second air outlet  2320 . The closer the valve member  2410  to the first end position the greater the proportion of the primary airflow that comprises the first portion that is directed to the first air outlet  2310 . Conversely, the closer the valve member  2410  to the second end position the greater the proportion of the primary airflow that comprises the second portion that is directed to the to the second air outlet  2320 . 
     The emission of the primary airflow or a portion of the primary airflow from the first air outlet  2310  in a direction that is substantially parallel to a central axis (X) of the opening/bore  2500  defined by the nozzle  2300  causes a secondary airflow to be generated by the entrainment of air from the external environment, specifically from the region around the nozzle  2500 . This secondary airflow combines with the primary airflow emitted from the first air outlet  2310  to produce a combined, amplified airflow that is projected forward from the nozzle  2300 . In contrast, emission of the primary airflow from the second air outlet  2320  such that the primary airflow substantially radiates/divaricates away from the fan assembly  1000  prevents this airflow from drawing air from outside the fan assembly  1000  through the opening/bore  2500  defined by the nozzle  2300 , thereby producing a non-amplified airflow. 
     The fan assemblies described herein can therefore deliver either an amplified airflow or a non-amplified airflow or simultaneously deliver both an amplified airflow and a non-amplified airflow, and in doing so provides the user of the fan assembly with various options as to how air is delivered by the fan assembly. This is particularly useful when the fan assembly is configured to provide purified air as the user of a fan assembly may wish to continue to receive purified air from the fan assembly without the cooling effect produced by the provision of the amplified airflow. For example, this may be the case in winter when the user may consider the temperature to be too low to make use of the cooling effect provided by the amplified airflow. Similarly, if the fan assembly is configured to provide heated air, then the user of a fan assembly may wish to continue to receive purified air from the fan assembly without the need for a focussed, amplified airflow, with a non-directional, non-amplified airflow then being delivered by the second air outlet. 
     For example, should the user wish to receive purified air from the fan assembly without the cooling effect produced by the provision of the amplified airflow, then the user can control the air delivery mode by manipulating the user interface. In response to these user inputs, the main control circuit would then cause the one or more valve members to prevent or obstruct the airflow from reaching the one or more first air outlets, so that the entirety of the primary airflow is directed out through one or more second air outlets. The fan assembly would then produce only the non-amplified airflow. Alternatively, the user may wish to only partially reduce the cooling effect produced by the provision of the amplified airflow. In this case, the user inputs would instruct the main control circuit to cause the valve member to move so as to reduce the proportion of the primary airflow that is directed to the one or more first air outlets, whilst increasing the proportion of the primary airflow that is directed to the one or more second air outlets. 
     Moreover, in the above described embodiments the one or more second air outlets of the fan assembly are configured to direct the non-amplified airflow such that it substantially radiates/divaricates perpendicularly away from a central axis of the bore defined by the nozzle. These embodiments therefore also provide that the non-amplified airflow is emitted diffusely, thereby providing for indirect delivery of the primary airflow to the user. In contrast, the one or more first air outlets of the fan assembly is configured to direct the emitted the airflow so that it is substantially parallel to a central axis of the bore defined by the nozzle, thereby providing for a more direct, focussed delivery of the amplified airflow to the user. The more diffuse delivery of the non-amplified airflow by the one or more second air outlets may also be desirable so as to further minimise the cooling effect produced by the provision of the focussed, amplified airflow. 
     It will be appreciated that individual items described above may be used on their own or in combination with other items shown in the drawings or described in the description and that items mentioned in the same passage as each other or the same drawing as each other need not be used in combination with each other. In addition, the expression “means” may be replaced by actuator or system or device as may be desirable. In addition, any reference to “comprising” or “consisting” is not intended to be limiting in any way whatsoever and the reader should interpret the description and claims accordingly. 
     Furthermore, although the invention has been described in terms of preferred embodiments as set forth above, it should be understood that these embodiments are illustrative only. Those skilled in the art will be able to make modifications and alternatives in view of the disclosure which are contemplated as falling within the scope of the appended claims. For example, those skilled in the art will appreciate that the above-described invention might be equally applicable to other types of environmental control fan assemblies, and not just free standing fan assemblies. By way of example, such a fan assembly could be any of a freestanding fan assembly, a ceiling or wall mounted fan assembly and an in-vehicle fan assembly. 
     By way of further example, whilst the above described embodiments all provide that the nozzle comprises the second air outlet, the second air outlet could be provided on the body/stand of the fan assembly or in the neck of the of the nozzle that connects to the body/stand of the fan assembly, with the valve then be arranging to direct the airflow accordingly. 
     As a yet further example, whilst the first embodiment illustrated in  FIGS. 1 to 9  includes heater assemblies within the first airflow channel that are configured to heat the primary airflow as it passes through the first airflow channel to the first air outlets, the fan assemblies described herein could alternatively or in addition be provided with one or more heater assemblies within the second airflow channel that would then be configured heat the primary airflow as it passes through the second airflow channel to the second air outlets. 
     In addition, whilst the above described embodiments all provide a valve motor for driving the movement of the valve member of the valve, the nozzles described herein could alternatively include a manual mechanism for driving the movement of the valve member, wherein the application of a force by the user would be translated into movement of the valve member. For example, this could take the form of a rotatable dial or wheel or a sliding dial or switch, with rotation or sliding of the dial by a user causing rotation of the shaft, pinion and rack. 
     Furthermore, from the above described embodiments it is clear that the fan assembly could comprise one or more first outlets and/or one or more second air outlets. In the case that the fan assembly comprises more than one first air outlet and/or more than one second air outlet, the fan assembly could then comprise either a single valve member for directing the primary airflow to one or both of the first air outlet(s) and second air outlet(s) or could comprise a plurality of valve member that between them direct the primary airflow to one or both of the first air outlet(s) and second air outlet(s). For example, the fan assembly could comprise a valve member corresponding to each of the first air outlets and/or each of the second air outlets.