GB2484671A

GB2484671A - A fan assembly comprising an adjustable surface for control of air flow

Info

Publication number: GB2484671A
Application number: GB201017552A
Authority: GB
Inventors: Nicholas Gerald Fitton; James John Thorn; Timothy Nicholas Stickney
Original assignee: Dyson Technology Ltd
Current assignee: Dyson Technology Ltd
Priority date: 2010-10-18
Filing date: 2010-10-18
Publication date: 2012-04-25
Also published as: GB201105688D0; GB201017552D0; GB2486749A

Abstract

A fan assembly includes a mouth 18 and comprises a nozzle 16 and a surface 72 located adjacent the mouth and over which the mouth directs the air flow. The surface comprises a diffuser portion. To allow a parameter of an air flow to be adjusted by a user, the surface is movable relative to the mouth. The fan is typically a bladeless fan. The surface may be adjusted between a number of different settings and comprises a set of moveable parts which may be rotated and/or slid and/or a section of cutaway parts which may be covered by adjusting the surface configuration and/or surface parts which may be changed between stowed and deployed positions. The surface may be a Coanda surface.

Description

A FAN ASSEMBLY

FIELD OF THE INVENTION

The present invention relates to a fan assembly. Particularly, but not exclusively, the present invention relates to a floor or table-top fan assembly, such as a desk, tower or pedestal fan.

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 air flow. The movement and circulation of the air flow 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 air flow to pass through the housing while preventing users from coming into contact with the rotating blades during use of the fan.

WO 2009/030879 describes a fan assembly which does not use caged blades to project air from the fan assembly. Instead, the fan assembly comprises a cylindrical base which houses a motor-driven impeller for drawing a primary air flow into the base, and an annular nozzle connected to the base and comprising an annular mouth through which the primary air flow 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 air flow emitted from the mouth, amplifying the primary air flow. The nozzle includes a Coanda surface over which the mouth is arranged to direct the primary air flow. The Coanda surface extends symmetrically about the central axis of the opening so that the air flow generated by the fan assembly is in the form of an annular jet having a cylindrical or frusto-conical profile.

I

SUMMARY OF THE INVENTION

The present invention provides a fan assembly comprising a nozzle and means for creating an air flow through the nozzle. The nozzle includes an interior passage, a mouth for receiving the air flow from the interior passage, and a surface located adjacent the mouth and over which the mouth is arranged to direct the air flow. The surface includes a diffuser portion downstream from the mouth and a guide portion downstream from the diffuser portion and angled thereto. To vary at least one parameter of an air flow generated by the fan assembly, at least part of the surface is moveable relative to the mouth or other part of the nozzle.

The at least one parameter of the combined air flow may comprise at least one of the profile, orientation, direction, flow rate (as measured, for example, in litres per second), and velocity of the combined air flow. Thus, through adjusting the surface over which the air flow emitted from the mouth is directed, a user may adjust the direction in which the air flow is projected forward from the fan assembly, for example to angle the air flow towards or away from a person in the vicinity of the fan assembly. Alternatively, or additionally, the user may expand or restrict the profile of the air flow to increase or decrease the number of users within the path of the air flow. As another alternative the user may change the orientation of the air flow, for example through the rotation of a relatively narrow air flow to provide a relatively wide air flow for cooling a number of users.

The part of the surface may adopt one of a number of discrete configurations. The part of the surface may be locked in a selected configuration so that the configuration of the surface cannot be adjusted later by a user. However, it is preferred that the part of the surface may be releasable or otherwise moveable from a selected configuration to allow a user to adjust the configuration of the surface as required during the use of the fan assembly.

The part of the surface may be adjusted manually by the user, or it may be adjusted automatically by an automated mechanism of the fan assembly, for example in response to a user operation of a user interface of the fan assembly. This user interface by be located on a body of the fan assembly, or it may be provided by a remote control connected wirelessly to the fan assembly.

The part of the surface may be rotated, translated, pivoted, extended, retracted, expanded, contracted, slid or otherwise moved relative to another part of the nozzle, for example the mouth of the nozzle.

The part of the surface may be moveable relative to another part of the nozzle between a stowed position and at least one deployed position to vary a parameter of the air flow generated by the fan assembly. In the stowed position the moveable part of the surface may be shielded from the air flow, whereas in each of the deployed positions the moveable part of the surface may adjust a parameter of the air flow generated by the fan assembly by a respective amount. For example, in each of the deployed positions the moveable part of the surface may be exposed to the air flow by a respective different amount.

Preferably, the surface over which the mouth is arranged to direct the air flow comprises a Coanda surface. A Coanda surface is a known type of surface over which fluid flow exiting an output orifice close to the surface exhibits the Coanda effect. The fluid tends to flow over the surface closely, almost clinging to' or hugging' the surface. The Coanda effect is already a proven, well documented method of entrainment in which a primary air flow is directed over a Coanda surface. A description of the features of a Coanda surface, and the effect of fluid flow over a Coanda surface, can be found in articles such as Reba, Scientific American, Volume 214, June 1966 pages 84 to 92.

Through use of a Coanda surface, an increased amount of air from outside the fan assembly is drawn through the opening by the air emitted from the mouth.

In a preferred embodiment an air flow is created through the nozzle of the fan assembly.

In the following description this air flow will be referred to as the primary air flow. The primary air flow is emitted from the mouth of the nozzle and preferably passes over a Coanda surface. The primary air flow entrains air surrounding the nozzle, which acts as an air amplifier to supply both the primary air flow and the entrained air to the user.

The entrained air will be referred to here as a secondary air flow. The secondary air flow is drawn from the room space, region or external environment surrounding the mouth of the nozzle and, by displacement, from other regions around the fan assembly, and passes predominantly through the opening defined by the nozzle. The primary air flow directed over the Coanda surface combined with the entrained secondary air flow equates to a total air flow emitted or projected forward from the opening defined by the nozzle.

The diffuser portion located downstream from the mouth may thus form part of a Coanda surface. The diffuser portion preferably extends about an axis, and preferably tapers towards or away from the axis. The angle subtended between the diffuser portion and the axis is preferably in the range from 5 to 35°.

The surface of the nozzle includes a guide portion located downstream of the diffuser portion and angled thereto for channelling the combined air flow generated by the fan assembly. The guide portion may comprise a first section connected to, and preferably integral with, the diffuser portion, and a second section which is moveable relative to the first section. The second section may be moveable about the first section.

The first section of the guide portion may comprise a cutaway portion, with the second section being moveable relative to the first section between a stowed position to allow air to pass through the cutaway portion and a fully deployed position to prevent air from passing through the cutaway portion.

Alternatively, the first section of the guide portion may comprise a plurality of cutaway portions, with the second section of the guide portion being moveable relative to the first section between a stowed position to allow air to pass through at least one of the cutaway portions, and a deployed position to prevent air from passing through at least one of the cutaway portions. For example, the second section may be moveable to cover a selected one of the cutaway portions by a desired amount. Alternatively, the second section may be moveable to cover simultaneously each of the cutaway portions when in its fully deployed position.

The cutaway portions may be regularly or irregularly spaced about the guide portion.

The cutaway portions are preferably arranged in an annular array. The cutaway portions may have the same or different sizes and/or shapes. The, or each, cutaway portion may have any desired shape. In a preferred embodiment the, or each, cutaway portion has a shape which is generally arcuate, but the, or each, cutaway portion may be circular, oval, polygonal or irregular.

The, or each, cutaway portion is preferably located at or towards a front edge of the nozzle. For example, the second section may comprise cutaway portions located on opposite sides thereof These cutaway portions may be located at side extremities of the guide portion, and/or at upper and lower extremities of the guide portion. The second section of the guide portion may be generally annular in shape, and rotated relative to the first section by the user to selectively cover one or more of the cutaway portions.

Preferably, the nozzle defines an opening through which air from outside the fan assembly is drawn by the air flow emitted from the mouth. The interior passage preferably extends continuously about the opening so that the opening is an enclosed opening which is surrounded by the interior passage. The mouth and the surface preferably extend about the opening, more preferably continuously about the opening.

The nozzle is preferably in the form of a loop extending about the opening. The mouth is preferably continuous about the nozzle, and may be substantially circular in shape.

Preferably, the mouth has one or more outlets, and the spacing between opposing surfaces of the nozzle at the outlet(s) of the mouth is preferably in the range from 0.5 to mm.

The nozzle is preferably mounted on a base housing said means for creating an air flow.

In the preferred fan assembly the means for creating an air flow through the nozzle comprises an impeller driven by a motor.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred features of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a front perspective view, from above, of a fan assembly, with a nozzle of the fan assembly in a first configuration; Figure 2 is a left side view of the fan assembly of Figure 1; Figure 3 is a top view of the fan assembly of Figure 1; Figure 4 is a front view of the fan assembly of Figure 1; Figure 5 is a side sectional view of the fan assembly, taken along line A-A in Figure 4; Figure 6 is a front perspective view, from above, of a fan assembly, with the nozzle in a second configuration; Figure 7 is a front perspective view, from above, of a fan assembly, with the nozzle in a third configuration; Figure 8 is a front perspective view, from above, of another fan assembly, with a nozzle of the fan assembly in a first configuration; and Figure 9 is a front perspective view, from above, of the fan assembly of Figure 8 with the nozzle in a second configuration.

DETAILED DESCRIPTION OF THE INVENTION

Figures ito 4 are external views of a fan assembly 10. The fan assembly 10 comprises a body 12 comprising an air inlet 14 through which a primary air flow enters the fan assembly 10, and a nozzle 16 in the form of an annular casing mounted on the body 12, and which comprises a mouth 18 for emitting the primary air flow from the fan assembly 10.

The body 12 comprises a substantially cylindrical main body section 20 mounted on a substantially cylindrical lower body section 22. The main body section 20 and the lower body section 22 preferably have substantially the same external diameter so that the external surface of the upper body section 20 is substantially flush with the external surface of the lower body section 22. In this embodiment the body 12 has a height in the range from 100 to 300 mm, and a diameter in the range from 100 to 200 mm.

The main body section 20 comprises the air inlet 14 through which the primary air flow enters the fan assembly 10. In this embodiment the air inlet 14 comprises an array of apertures formed in the main body section 20. Alternatively, the air inlet 14 may comprise one or more grilles or meshes mounted within windows formed in the main body section 20. The main body section 20 is open at the upper end (as illustrated) thereof to provide an air outlet 23 through which the primary air flow is exhausted from the body 12.

The main body section 20 may be tilted relative to the lower body section 22 to adjust the direction in which the primary air flow is emitted from the fan assembly 10. For example, the upper surface of the lower body section 22 and the lower surface of the main body section 20 may be provided with interconnecting features which allow the main body section 20 to move relative to the lower body section 22 while preventing the main body section 20 from being lifted from the lower body section 22. For example, the lower body section 22 and the main body section 20 may comprise interlocking L-shaped members.

The lower body section 22 comprises a user interface of the fan assembly 10. The user interface comprises a plurality of user-operable buttons 24, 26, a dial 28 for enabling a user to control various functions of the fan assembly 10, and user interface control circuit 30 connected to the buttons 24, 26 and the dial 28. The lower body section 22 is mounted on a base 32 for engaging a surface on which the fan assembly 10 is located.

Figure 5 illustrates a sectional view through the body fan assembly. The lower body section 22 houses a main control circuit, indicated generally at 34, connected to the user interface control circuit 30. In response to operation of the buttons 24, 26 and the dial 28, the user interface control circuit 30 is arranged to transmit appropriate signals to the main control circuit 34 to control various operations of the fan assembly 10.

The lower body section 22 also houses a mechanism, indicated generally at 36, for oscillating the lower body section 22 relative to the base 32. The operation of the oscillating mechanism 36 is controlled by the main control circuit 34 in response to the user operation of the button 26. The range of each oscillation cycle of the lower body section 22 relative to the base 32 is preferably between 60° and 120°, and in this embodiment is around 80°. In this embodiment, the oscillating mechanism 36 is arranged to perform around 3 to S oscillation cycles per minute. A mains power cable 38 for supplying electrical power to the fan assembly 10 extends through an aperture formed in the base 32. The cable 38 is connected to a plug (not shown) for connection to a mains power supply.

The main body section 20 houses an impeller 40 for drawing the primary air flow through the air inlet 14 and into the body 12. Preferably, the impeller 40 is in the form of a mixed flow impeller. The impeller 40 is connected to a rotary shaft 42 extending outwardly from a motor 44. In this embodiment, the motor 44 is a DC brushless motor having a speed which is variable by the main control circuit 34 in response to user manipulation of the dial 28. The maximum speed of the motor 44 is preferably in the range from 5,000 to 10,000 rpm. The motor 44 is housed within a motor bucket comprising an upper portion 46 connected to a lower portion 48. The upper portion 46 of the motor bucket comprises a diffuser 50 in the form of a stationary disc having spiral blades.

The motor bucket is located within, and mounted on, a generally frusto-conical impeller housing 52. The impeller housing 52 is, in tum, mounted on a plurality of angularly spaced supports 54, in this example three supports, located within and connected to the main body section 20 of the base 12. The impeller 40 and the impeller housing 52 are shaped so that the impeller 40 is in close proximity to, but does not contact, the inner surface of the impeller housing 52. A substantially annular inlet member 56 is connected to the bottom of the impeller housing 52 for guiding the primary air flow into the impeller housing 52. An electrical cable 58 passes from the main control circuit 34 to the motor 44 through apertures formed in the main body section 20 and the lower body section 22 of the body 12, and in the impeller housing 52 and the motor bucket.

Preferably, the body 12 includes silencing foam for reducing noise emissions from the body 12. In this embodiment, the main body section 20 of the body 12 comprises a first foam member 60 located beneath the air inlet 14, and a second annular foam member 62 located within the motor bucket.

A flexible sealing member 64 is mounted on the impeller housing 52. The flexible sealing member prevents air from passing around the outer surface of the impeller housing 52 to the inlet member 56. The sealing member 64 preferably comprises an annular lip seal, preferably formed from rubber. The sealing member 64 further comprises a guide portion in the form of a grommet for guiding the electrical cable 58 to the motor 44.

Returning to Figures 1 to 4, the nozzle 16 has an annular shape, extending about a central axis X to define an opening 70. The mouth 18 is located towards the rear of the nozzle 16, and is arranged to emit the primary air flow towards the front of the fan assembly 10, through the opening 70. The mouth 18 surrounds the opening 70. In this example, the nozzle 16 defines a generally circular opening 70 located in a plane which is generally orthogonal to the central axis X. The innermost, external surface of the nozzle 16 comprises a Coanda surface 72 located adjacent the mouth 18, and over which the mouth 18 is arranged to direct the air emitted from the fan assembly 10. The Coanda surface 72 comprises a diffuser portion 74 tapering away from the central axis X. In this example, the diffuser portion 74 is in the form of a generally fmsto-conical surface extending about the axis X, and which is inclined to the axis X at an angle in the range from 5 to 35°, and in this example is around 28°.

The nozzle 16 comprises an annular front casing section 76 connected to and extending about an annular rear casing section 78. The annular sections 76, 78 of the nozzle 16 extend about the central axis X. Each of these sections may be formed from a plurality of connected parts, but in this embodiment each of the front casing section 76 and the rear casing section 78 is formed from a respective, single moulded part. The rear casing section 78 comprises a base 80 which is connected to the open upper end of the main body section 20 of the body 12, and which has an open lower end for receiving the primary air flow from the body 12.

With reference also to Figure 5, during assembly, the front end 82 of the rear casing section 78 is inserted into a slot 84 located in the front casing section 76. Each of the front end 82 and the slot 84 is generally cylindrical. The casing sections 76, 78 may be connected together using an adhesive introduced to the slot 84.

The front casing section 76 defines the Coanda surface 72 of the nozzle 16. The front casing section 76 and the rear casing section 78 together define an annular interior passage 88 for conveying the primary air flow to the mouth 18. The interior passage 88 extends about the axis X, and is bounded by the internal surface 90 of the front casing section 76 and the internal surface 92 of the rear casing section 78. The base 80 of the front casing section 76 is shaped to convey the primary air flow into the interior passage 88 of the nozzle 16.

The mouth 18 is defined by overlapping, or facing, portions of the internal surface 92 of the rear casing section 78 and the external surface 94 of the front casing section 76, respectively. The mouth 18 preferably comprises an air outlet in the form of an annular slot. The slot is preferably generally circular in shape, and preferably has a relatively constant width in the range from 0.5 to 5 mm. In this example the air outlet has a width of around 1 mm. Spacers may be spaced about the mouth 18 for urging apart the overlapping portions of the front casing section 76 and the rear casing section 78 to control the width of the air outlet of the mouth 18. These spacers may be integral with either the front casing section 76 or the rear casing section 78. The mouth 18 is shaped to direct the primary air flow over the external surface 94 of the front casing section 76.

The external surface of the nozzle 16 also comprises a guide portion 96 located downstream from the diffuser portion 74 and angled thereto. The guide portion 96 similarly extends about the axis X. The guide portion 96 may be inclined to the axis X by an angle in the range from -30 to 30°, but in this example the guide portion 96 is generally cylindrical and is centred on the axis X. The depth of the guide portion 96, as measured along the axis X, is preferably in the range from 20 to 80% of the depth of the diffuser portion 74, and in this example is around 60%.

The guide portion 96 comprises a first section 98 which is connected to, and preferably integral with, the diffuser portion 74 of the Coanda surface 72, and a second section 100 which is moveable relative to the first section 98 to adjust a parameter of the air flow generated by the fan assembly 10. In this example, the first section 98 of the guide portion 96 of the nozzle 16 comprises an upper portion 102 and a lower portion 104.

Each of the upper portion 102 and the lower portion 104 is in the form of a partially cylindrical surface centred on the axis X, and which extends about the axis X by an angle which is preferably in the range from 30 to 150°, and in this example is around 1200. The upper and lower portions 102, 104 are separated by a pair of cutaway portions 106, 108 of the first section 98. In this example each cutaway portion 106, 108 is located at a respective side of the first section 98, and extends from the front edge 110 of the first section 98 to the substantially circular front edge 112 of the diffuser portion 74. The cutaway portions 106, 108 have generally the same size and shape, and in this example each extend around 60° about the axis X. The second section 100 of the guide portion 96 is generally annular in shape, and is mounted on the external surface of the nozzle 16 so as to extend about the first section 98 of the guide portion 96. The second section 100 has a generally cylindrical curvature, and is also centred on the axis X. The front edge 114 of the second section is substantially co-planar with the front edge 110 of the first section 98, whereas the substantially circular rear edge 116 is located rearwardly of the first section 96 so as to surround the diffuser portion 74 of the Coanda surface 72.

The depth of the second section 100 of the guide portion 96, as measured along the axis X, varies about the axis X. The second section 100 comprises two forwardly extending portions 118, 120 which are connected by arcuate connectors 122, 124. The forwardly extending portions 118, 120 of the second section 100 have generally the same size and shape as the upper and lower portions 102, 104 of the front section 98. The connectors 122, 124 are relatively narrow, and are located behind the front edge 112 of the diffuser portion 74 of the Coanda surface 72 so that these connectors 122, 124 are not exposed to the air flow generated by the fan assembly 10.

As mentioned above, the second section 100 of the guide portion 96 is moveable relative to the first section 98 of the guide portion 96. In this example, the second section 100 is located about the first section 98 so as to be rotatable about the axis X. The second section 100 comprises a pair of tabs 126 which extend radially outwardly to allow a user to grip the tabs to rotate the second section 100 relative to the first section 98. In this example, the second section 100 slides over the first section 98 as it is moved relative thereto. The inner surface of the second section 100 may comprise a radially inwardly extending ridge, which may extend partially or fully about the axis X, which is received within an annular groove formed on the outer surface of the front casing section 76 and which guides the movement of the second section 100 relative to the first section 98.

To operate the fan assembly 10 the user the user presses button 24 of the user interface.

The user interface control circuit 30 communicates this action to the main control circuit 34, in response to which the main control circuit 34 activates the motor 44 to rotate the impeller 40. The rotation of the impeller 40 causes a primary air flow to be drawn into the body 12 through the air inlet 14. The user may control the speed of the motor 44, and therefore the rate at which air is drawn into the body 12 through the air inlet 14, by manipulating the dial 28 of the user interface. Depending on the speed of the motor 44, the primary air flow generated by the impeller 40 may be between 10 and 30 litres per second. The primary air flow passes sequentially through the impeller housing 52 and the air outlet 23 at the open upper end of the main body portion 20 to enter the interior passage 88 of the nozzle 16. The pressure of the primary air flow at the air outlet 23 of the body 12 may be at least 150 Pa, and is preferably in the range from 250 to 1.5 kPa.

Within the interior passage 88 of the nozzle 16, the primary air flow is divided into two air streams which pass in opposite directions around the opening 70 of the nozzle 16.

As the air streams pass through the interior passage 70, air is emitted through the mouth 18. The primary air flow emitted from the mouth 18 is directed over the Coanda surface 72 of the nozzle 16, causing a secondary air flow to be generated by the entrainment of air from the external environment, specifically from the region around the mouth 18 and from around the rear of the nozzle 16. This secondary air flow passes through the central opening 70 of the nozzle 16, where it combines with the primary air flow to produce a combined, or total, air flow, or air current, projected forward from the nozzle 16.

As part of the nozzle 16, in this example the second section 100 of the guide portion 96 of the nozzle 16, is moveable relative to the remainder of the nozzle 16, the nozzle 16 may adopt one of a number of different configurations. Figures 1 to 5 illustrate the nozzle 16 in a first configuration, in which the second section 100 of the guide portion 96 is in a stowed position relative to the other parts of the nozzle 16. In this stowed position the forwardly extending portions 118, 120 of the second section 100 are located radially behind the upper and lower portions 102, 104 of the front section 98 so that the second section 100 is substantially fully shielded from the air flow. This allows part of the combined air flow to pass through the cutaway portions 106, 108 of the first section 96 without being channelled or focussed towards the axis X by the guide portion 96 of the nozzle 16.

As the angle of the diffuser portion 74 of the Coanda surface 72 is relatively wide, in this example around 28°, the profile of the combined air flow projected forward from the fan assembly 10 will be relatively wide. However, in view of the partial guiding of the combined air flow towards the axis X, the profile of the air current generated by the fan assembly 10 is non-circular. The profile is generally oval, with the height of the profile being smaller than the width of the profile. This flattening, or widening, of the profile of the air current in this nozzle configuration can make the fan assembly 10 particularly suitable for use as a desk fan in a room, office or other environment to deliver a cooling air current simultaneously to a number of users in proximity to the fan assembly 10.

By gripping the tabs 126 of the second section 100 of the guide portion 96, a user may rotate the second section 100 relative to the first section 98 to change the configuration of the nozzle 16. Figure 6 illustrates the fan assembly 10 in a second configuration in which the second section 100 is in a partially deployed position relative to the other parts of the nozzle 16 following a partial rotation of the second section 100 about the first section 98. In this partially deployed position, the forwardly extending portions 118, 120 of the second section 100 partially cover the cutaway portions 106, 108 of the first section 96, changing the profile of the combined air and increasing the proportion of the combined air flow which is channelled towards a user located in front of the fan assembly 10.

Figure 7 illustrates the fan assembly 10 in a third configuration in which the second section 100 is in a fully deployed position relative to the other parts of the nozzle 16 following a further partial rotation of the second section 100 about the first section 98.

In this fully deployed position, the forwardly extending portions 118, 120 of the second section 100 cover fully the cutaway portions 106, 108 of the first section 96, again changing the profile of the combined air so that all of the combined air flow is channelled towards a user located in front of the fan assembly 10. The upper and lower portions 102, 104 of the front section 98 and the forwardly extending portions 118, 120 of the second section 100 provide a substantially continuous, substantially cylindrical guide surface for channelling the combined air flow towards the user, and so the profile of the combined air flow, in this nozzle configuration, is generally circular. This focussing of the profile of the air flow can make the fan assembly 10 particularly suitable for use as a desk fan in a room, office or other environment to deliver a cooling air current simultaneously to a single user in proximity to the fan assembly 10.

The movement of the nozzle 16 between these configurations also varies the flow rate and the velocity of the combined air flow generated by the fan assembly 10. When the second section 100 is in the stowed position, the combined air flow has a relatively high flow rate but a relatively low velocity. When the second section 100 is in the fully deployed position, the combined air flow has a relatively low flow rate but a relatively high velocity.

As an altemative to locating the portions 102, 104 of the front section 98 at the upper and lower extremities of the guide portion 96, these portions may be located at the side extremities of the guide portion 96. Thus, when the second section 100 is in its stowed position, the height of the profile of the air current may be greater than the width of the profile. This stretching of the profile of the air current in a vertical direction can make the fan assembly particularly suitable for use as a floor standing tower or pedestal fan.

In the fan assembly 10, the second section 100 is arranged to cover simultaneously both of the cutaway portions 106, 108 when in its fully deployed position. Figures 8 and 9 illustrate another fan assembly 10', which differs from the fan assembly 10 in that the forwardly extending portion 120 has been omitted from the second section 100 of the guide portion 96. In view of this, the second section 100 is moveable from a stowed position in which, similar to the fan assembly 10, air can flow through both of the cutaway portions 106, 108 of the first section 98, to one of a first fully deployed position and a second fully deployed position. In the first fully deployed position, illustrated in Figure 8, only the cutaway portion 108 is covered fully by the second section 100 whereas in the second fully deployed position, illustrated in Figure 9, only the cutaway portion 106 is covered fully by the second section 100. The movement of the second section 100 between these fully deployed positions thus not only changes the profile of the combined air flow, but also changes the direction and the orientation of the combined air flow.

In this example, the change in the orientation of the combined air flow between the first and second fully deployed positions is around 180°. Thus, the movement of the nozzle 16 between these two configurations, in which the second section 100 is in the first fully deployed position and the second fully deployed position respectively, can produce an effect which is similar to that produced by oscillating the lower body section 22 relative to the base 32, that is, a sweeping of the combined air flow over an arc during the use of the fan assembly 10. Mechanising the movement of the second section 100 relative to the first section 98 can thus provide an alternative means of sweeping the combined air flow over an arc.

Claims

CLAIMS1. A fan assembly comprising a nozzle and means for creating an air flow through the nozzle, the nozzle comprising an interior passage, a mouth for receiving the air flow from the interior passage, and a surface located adjacent the mouth and over which the mouth is arranged to direct the air flow, the surface comprising a diffuser portion downstream from the mouth and a guide portion downstream from the diffuser portion and angled thereto, characterised in that at least part of the surface is moveable relative to the mouth.
2. A fan assembly as claimed in claim 1, wherein said at least part of the surface is rotatable relative to the mouth.
3. A fan assembly as claimed in claim 1 or claim 2, wherein said at least part of the surface is slidably moveable relative to the mouth.
4. A fan assembly as claimed in any preceding claim, wherein said at least part of the surface is moveable relative to the mouth between a stowed position and at least one deployed position.
5. A fan assembly as claimed in claim 4, wherein, in said stowed position, said at least part of the surface is shielded from the air flow.
6. A fan assembly as claimed in any preceding claim, wherein the guide portion comprises a first section connected to the diffuser portion, and a second section which is moveable relative to the first section.
7. A fan assembly as claimed in claim 6, wherein the second section is moveable about the first section.
8. A fan assembly as claimed in claim 6 or claim 7, wherein the first section comprises a cutaway portion, and wherein the second section is moveable relative to the first section to allow air to pass through the cutaway portion.
9. A fan assembly as claimed in claim 6 or claim 7, wherein the first section comprises a plurality of cutaway portions, and wherein the second section is moveable relative to the first section to allow air to pass through at least one of the cutaway portions.
10. A fan assembly as claimed in claim 9, wherein the second section is moveable relative to the first section to allow air to pass through each of the cutaway portions simultaneously.
11. A fan assembly as claimed in claim 9 or claim 10, wherein the cutaway portions are regularly spaced about the guide portion of the surface..
12. A fan assembly as claimed in any of claims 8 to 11, wherein the, or each, cutaway portion is located at or towards a front edge of the nozzle.
13. A fan assembly as claimed in any of claims 7 to 12, wherein the first section of the guide portion is annular in shape.
14. A fan assembly as claimed in any of claims 7 to 13, wherein the second section of the guide portion is annular in shape.
15. A fan assembly as claimed in any preceding claim, wherein the mouth is annular in shape.
16. A fan assembly as claimed in any preceding claim, wherein the nozzle is mounted on a base housing said means for creating an air flow.
17. A fan assembly as claimed in any preceding claim, wherein said at least part of the surface is moveable manually.