GB2575621A

GB2575621A - Hand held appliance

Info

Publication number: GB2575621A
Application number: GB1808450.9A
Authority: GB
Inventors: Haruna Waters Imhasly Nathan; Mark Brett Coulton Robert; Farrar Smith Stephen; Papotti Gabor
Original assignee: Dyson Technology Ltd
Current assignee: Dyson Technology Ltd
Priority date: 2018-05-23
Filing date: 2018-05-23
Publication date: 2020-01-22
Anticipated expiration: 2038-05-23
Also published as: GB2575621B; WO2019224508A1; CN214711012U; GB201808450D0; CN217364923U

Abstract

A hair care appliance comprises a housing (200, fig 1) and a fluid flow path extending from a fluid inlet (212, fig.1) to a fluid outlet (202, fig. 2a). A heater 80 comprises a heater element 82, a former 86 around which the heater element is wound and an outer wall (180, fig.8b) which extends around the heater element. The former provides a central region which is devoid of the heater element. The heater element provides an intermediate region which extends around the central region. An outer region extends between the intermediate region and the outer wall and is devoid of the heater clement. The appliance may comprise an attachment (20, fig.1) having a second fluid flow path extending from a second fluid inlet to a second fluid outlet (22, fig.1), wherein the attachment extends along an axis, preferably parallel to the housing axis, and the second fluid outlet extends at least partially along that axis. Also disclosed is an appliance having flow guides (130, fig.5a; 30, fig.4a) to direct fluid to an inlet of a fan unit (70, fig 2a).

Description

Hand held Appliance

This invention relates to a heater for a hand held appliance and in particular for a hair care appliance.

In a conventional hot styling appliance, air is drawn into an inlet by a fan unit, heated by a heater and directed towards the hair by an outlet. Often, one appliance is provided with different attachments, each having a different outlet and thus a different function, for example drying, curling or volumising. Depending on the style desired, the air may or may not be heated. The attachment may include bristles onto which hair is wrapped and held for styling.

The present invention seeks to provide a hair care appliance having improved performance.

Conventional heaters form the shape of a truncated cone having a diameter which changes along the whole length in order to heat fluid across the fluid outlet; each coil of the resistive wire of the heater has a slightly different diameter.

The invention provides a hair care appliance comprising a housing, a fluid flow path extending from a fluid inlet into the housing to a fluid outlet from the housing.

Thus, according to an aspect, the invention provides a hair care appliance comprising a housing, a fluid flow path extending from a fluid inlet into the housing to a fluid outlet from the housing, a heater extending at least partially along the housing wherein the heater comprises a heater element, a former around which the heater element is wound and an outer wall which extends around the heater element wherein the former provides a central region of the heater which is devoid of the heater element, the heater element provides an intermediate region which extends around the central region and the former provides an outer region extending between the intermediate region and the outer wall which is devoid of the heater element.

The former is a scaffold of an insulating material such as Mica which is generally formed as sheets which are subsequently slotted together to provide a 3D structure around which the heating element is wound. The former ensures that the heating element, which is resistive wire made from a metal such as tungsten, is retained in a desired location so each winding of the wire is separated to avoid creating hot spots.

The resistive wire is shaped into undulations similar to a sine wave to maximise the amount of heat that can be generated. The devoid regions are parts of the heater within the outer wall which free from the resistive wire.

Preferably, the hair care appliance comprises an attachment which can be attached and removed from the appliance and the attachment comprises a second fluid flow path extending from a second fluid inlet which is in fluid communication with the fluid outlet of the housing and a second fluid outlet wherein the attachment extends along an axis and the second fluid outlet extends at least partially along the axis.

Preferably, the axis along which the attachment extends is parallel to an axis along which the housing extends.

In conventional appliances, the heater shape is varied to try to get an even temperature across the fluid outlet in contrast, in this invention a temperature gradient has been introduced across the fluid outlet. This is so that the temperature gradient along the second fluid outlet - that of the attachment - is improved and minimised.

Preferably, the heater comprises a region of constant diameter. It is preferred that the region of constant diameter is positioned at an inlet end of the heater i.e. towards the fluid inlet into the appliance.

It is preferred that the heater comprises a region of varying diameter. It is preferred that the region of varying diameter is positioned at an outlet end of the heater i.e. towards the fluid outlet from the appliance. Preferably, the diameter increases from the constant diameter to a larger diameter.

By increasing the diameter for a period of the heater length, the heated fluid in the intermediate region mixes with the fluid in the outer region. This provides a more even temperature distribution along the length of the second fluid outlet.

Also disclosed is a hair care appliance comprising a housing, a fluid flow path extending from a fluid inlet into the housing to a fluid outlet from the housing, a fan unit extending at least partially along the housing wherein an inner flow guide is provided to direct fluid flowing through the fluid flow path to an inlet of the fan unit.

Preferably, the inner flow guide comprises a curved surface that extends from the housing towards the fan unit. It is preferred that the inner flow guide comprises fins that extend from the curved surface into the fluid flow path.

The fan unit comprises a fan and a motor.

Also disclosed is a hair care appliance comprising a housing, a fluid flow path extending from a fluid inlet into the housing to a fluid outlet from the housing, a fan unit extending at least partially along the housing wherein a further flow guide is provided to direct fluid flowing through the fluid flow path to an inlet of the fan unit.

Preferably, the further flow guide extends from the housing towards the fan unit and curves around a portion of an inner diameter of the housing and curves between the housing and the fan unit.

Preferably, the further flow guide forms part of a seal.

Preferably, the housing comprises an inner wall extending within the housing which includes an enclosure for the fan unit and the seal comprises a first branch which extends around the inner wall adjacent the enclosure.

It is preferred that the seal further comprises a second branch which extends from the first branch towards the housing.

In a preferred embodiment, the appliance is a hot styling device.

The invention will now be described by way of example, and with reference to the accompanying drawings, of which:

Figure 1 shows an example of an appliance according to the invention;

Figure 2a shows a cross-section through the appliance of Figure 1;

Figure 2b shows an enlarged portion of the cross-section of Figure 2;

Figure 3a shows a side view of a filter mesh according to the invention;

Figure 3b shows an isometric view of a filter mesh according to the invention cross section through of the grille shown in Figure 2;

Figures 4a and 4b show two isometric views of an internal flow guide;

Figures 5a and 5b show isometric views of an internal seal;

Figure 5c shows a cross-section through the internal seal of Figures 6a and 6b;

Figure 6a shows an exploded isometric view of part of a switch mechanism;

Figure 6b shows the switch mechanism of Figure 6a assembled;

Figure 6c shows a cross-section through the handle and switch mechanism of Figure 6a;

Figures 7a and 7b show side views of internal components of the appliance;

Figure 8a shows components of a heater according to the invention;

Figure 8b show schematically a cross section through the heater of Figure 8a; and

Figures 9a and 9b show stages in manufacture of a thermal fuse;

Referring to Figures 1, 2a and 2b, an example of a hand held appliance 10 is shown. The appliance has a handle 210 and an attachment 20 for styling hair. In order to enable a user to create different styles and to give the appliance multi functionality, the attachment 20 is removable and can be replaced with an alternative attachment. In addition, the attachment 20 can be removed to allow easier storage of the appliance when not in use. The handle 210 includes a UI (user interface) 230 comprising number of different user operated buttons 38, 138 enabling the user to select between a number of different heat and flow settings. The handle 210 includes a fan unit 70 and heater 80. The fan unit 70 has a motor 76 and a fan 78 which rotates when the motor is activated. In use the fan unit 70 draws fluid in through a fluid inlet 212, along a fluid flow path 100, through the heater 80 which optionally heats the fluid which is then emitted by the fluid outlet 22 in the attachment 20.

The UI 230 has externally accessible user operated buttons 38, 138 and these engage with internal switches located on a UI board 232. The UI board 232 is additionally used to provide housing for various other components such as an ion generator 40.

The handle 210 has an outer wall 200 which extends along a longitudinal axis X-X from the fluid inlet 212 towards the fluid outlet 202 and an inner wall 220 which houses the fan unit 70 and the heater 80. At the fluid inlet 212, the inner wall 220 extends radially inwards of the outer wall 200. However, in this embodiment, the outer wall 200 does not extend to the fluid outlet 202 thus for a portion 214 of the length of the handle 210, the inner wall 220 is an external wall of the appliance 10. For this portion of the length of the handle 210, the inner wall 220 is substantially the same diameter as the outer wall 200.

The fluid inlet 212 to the handle 210, fdters fluid that enters the fluid flow path 100.The outer wall 200 provides a filter grille 204 and the inner wall 220 a filter mesh 224. The filter mesh 224 is finer than the filter grille 204 and is adapted to catch dust and fluff. The filter grille 204 is removable to enable the filter mesh 224 to be cleaned periodically. Both the filter grille 204 and the filter mesh 224 have an array of apertures that extend continuously radially around the circumference of the handle 210.

In order to assist a user in understanding when the filter mesh 224 requires cleaning an indicator in the form of an LED 50 is provided (Figure 2b). In this example, the LED is located on a PCB (printed circuit board) 120 provided within the handle 210. A light pipe 52 extends from adjacent the LED 50 within a supporting rib 216 towards the outer wall 200 and an aperture 54 provided in the outer wall 200.

If the filter grille 204 is blocked then when the appliance 10 is turned on the fan unit 70 and in particular the motor 76 will not perform as expected. This is flagged as an error and the LED 50 is activated. In one embodiment, the LED 50 has three different modes: off indicating no problem; on with a first colour indicating to the user that the filter needs cleaning; and on with a second colour indicating to the user that there is a fault that cannot be remedied by the user so the product should be returned or assistance

e.g. by ringing a user help line should be sought. The first colour may be white and it may flash to catch the attention of the user. The second colour may be red.

Once fluid has entered the appliance 10, it is directed passed the PCB. The inner wall 220 conveniently provides a housing 222 for the PCB 120 which limits the position of the PCB 120. As the PCB 120 has differently sized and shaped electrical components mounted on it, having the PCB 120 contained within a housing 222 reduces turbulence, noise and pressure losses within the appliance 10. At a downstream end 120b of the PCB, the inner wall 220 curves around the end of the PCB 120 towards the fan unit 70. The shape of the downstream end 120b is designed to reduce separation of flow from the surface of the housing 222.

Referring now to Figures 3a and 3b, the PCB 120 includes an access port 122 which enables software updates to be applied to an appliance or data to be collected from an appliance. In order that this can be achieved without dismantling the appliance 10, the filter mesh 224 is provided with an aperture 228 which enables a connector (not shown) to plug into the access port 122. The aperture 228 is provided within a frame 226 which delimits and supports the filter mesh 224 and the aperture 228 is covered with a cover 124 during normal use of the product so that in use fluid that is drawn into the fluid inlet 212 must pass through both the filter mesh 204 and the filter grille 204. To utilise the access port 122, the filter grille 204 is removed which exposes the filter mesh 224 and the cover 124. The cover is removed using a tool such as an awl allowing a data cable to be plugged into the access port 122.

Between the PCB 120 and the fan unit 70 a grille 60 is provided. The grille 60 is provided to even out the fluid flow prior to fan unit 70 and its’ use reduces the noise produced within the appliance. The grille 60 and the fan unit 70 are the same crosssectional area and are both circular.

In order to accommodate features of the UI board 232, the fan unit 70 is off centre within the handle 210. The grille 60 is also off-centre as it aligns to the fan unit 70. The handle 210 has an oval cross sectional area which accommodates the fan unit 70 and the UI board 232 thus, the fluid flow path 100 is not straight through the handle 210. The fluid flow path 100 is non-parallel to the longitudinal axis X-X of the outer wall 200. At the fluid inlet 212, fluid enters the fluid flow path 100 and is directed around the housing 222 for the PCB 120 forming two generally semi-circular flows within the elliptical handle. A pair of reinforcing ribs 226 (Figure 2b) extends one from each side of the housing 222 for the PCB120 towards the outer wall 200 to protect components housing on the PCB 120 in the event of damage to the outer wall 200.

There is a gap 166 between the downstream end 120b of the housing 222 and the grille 60 and this gap 166 is provided to allow mixing of the fluid that flowed on either side of the PCB 120. There is a velocity mismatch between the fluid that flowed on either side of the PCB 120 and allowing space for these to mix reduces the mismatch, then the grille 60 evens the flow further and reduces the overall velocity.

To prevent fluid from hitting the part of the inner wall that contains the UI board 232, an inner flow guide which includes a curved wall section 30 is provided. (Figures 4a and 4b) The curved wall section 30 curves from an inner surface 200b of the outer wall 200 radially inwardly towards the fan unit 70 and the grille 60 and directs fluid within the fluid flow path 100 towards the fan unit 70. The curved wall section 30 compresses the fluid flow path, removing large eddies from the fluid. As the fluid flowing within the fluid flow path 100 prior to the fan unit 70 has been directed by the housing 222 of the PCB 120 and the curved wall section 30, the grille 60 is provided to even out the flow that is compressed towards the fan unit 70.

The inner flow guide includes two features to assist in the turning of the fluid flowing in the fluid flow path 100, the curved wall section 30 forms an arc extending between the inner surface 200b of the outer wall 200 and the grille 60. The curvature of the arc turns fluid flowing within the fluid flow path 100 so it smoothly enters the grille 60 and subsequently the fan unit 70. The second feature comprises a number of fins 32 that extend from the curved wall section 30 into the fluid flow path 100. The fins 32 maintain and straighten the flow as the flow is bent by the curved wall section 30. The fins 32 help reduce the introduction of turbulence as the flow is turned into the grille 60.

The inner flow guide is positioned on the same side as the UI 230 and the UI board 232. On the opposite side of the handle 210, there is a small gap between the outer wall 200 and the inner wall 220 and this transition is managed by a further flow guide 36 (Figures 5a to 5c). The further flow guide 36 curves in two dimensions; it curves around an inner surface 200b of the outer wall; and it curves between the outer wall 200 and the inner wall 220 where the inner wall provides a fan unit housing 218. The further flow guide 36 provides a curved surface which directs flow in the fluid flow path 100 into the grille 60 and the fan unit 70.

In this embodiment, the further flow guide 36 is provided as part of a seal 130 that extends around an inner surface 200b of the outer wall 200. The seal 130 bifurcates or forks and a first branch 132 extends around an outer surface 220a of the inner wall at a downstream end of the fan unit housing 224 and a second branch 134 extends from the first branch 132 to engage with an inner surface 200b of the outer wall 200. The seal 130 stops fluid flowing through the fluid flow path from flowing between the inner wall 220 and the outer wall 200 thus preventing recirculation around the fan unit 70.

The UI board 232 is located in a cavity between the outer wall 200 and the inner wall 220 and in order to fit the user operated buttons 38, 138 and the on off switch 150 in the available space they are longitudinally spaced within the cavity (Figures 6a to 6c).

An actuator 140 which includes an arm 144 extends between the button 138 and the switch 150. The actuator 140 has a protrusion 42 for engaging with the button 138. The protrusion 42 is housed within a housing 146. The housing 146 has an aperture 48 through which the protrusion 42 extends. The actuator 140 actually engages with two switches (one not shown) which are offset along the length of the arm 144 so the force along the length of the arm 144 is not necessarily balanced. To avoid any difficulties that would be caused by a displacement of the arm 144 and one of the switches not being properly activated the arm 144 is provided with torsion spring 148 adapted to push against another part and bias the arm 144 towards the switch 150. The torsion spring 148 is seated within a spring housing 142 which engages with the arm 144 and a UI board cover 236 this biases the arm 144 towards the switch 150 to ensure good engagement over life. The UI board cover 236 includes an arm 238 which extends radially inwards of the UI board cover 236 and a radially internal surface 238a engages with the spring housing 142.

The UI board cover 236 has three main functions: a first is to provide a fixed surface to engage with the spring housing 142; a second is to aid manufacture as wiring for various components such as the heater 80 are secured either partially between the inner wall 220 and the UI board cover 236 or within a channel or recess 240 provided on a radially outer surface 238b of the UI board cover 236.

Referring now to Figures 7a and 7b, in order to maintain the UI board 232 in the correct position, a pair of clips 250 is provided. The pair of clips 250 engages with both the UI board 232and the inner wall 220. One of the pair of clips 250 is provided at each side of the UI board 232where a side extends parallel to the longitudinal axis X-X of the appliance. The pair of clips 250 include a first recess (not shown) adapted to receive a protrusion 252 from the UI board 232and a second recess (not shown) adapted to retain a projection 254 that extends outwardly from an outer surface 220b of the inner wall 220. The pair of clips 250 snap fit into the protrusion 252 and projection 254 respectively.

The fluid outlet 22 from the attachment 20 is elongate and extends along a substantial length of the attachment 20. It is desirable to have consistent flow exiting along the length of the fluid outlet 22 and an even or consistent temperature of fluid that exits along the length. This assists in drying and styling the hair as different portions and tresses of hair are exposed to similar drying conditions. However, even when the flow exiting from the fluid outlet 22 along the length of the attachment 20 is consistent, the temperature of fluid exiting from the fluid outlet 22 may vary significantly. The former is controlled by features within the attachment 20 e.g. turning vanes whereas the latter is a function of the heater and the fluid flow path through the inner wall 220.

The heater 80 is formed from a resistive wire 82 which is formed into undulations 84 or zig zags and then wound around a former 86 made from a heat resistant material such as

Mica. An insulating wall 180 extends around the outer periphery of the heater 80. Where the heater is essentially cylindrical, the most efficient way to exchange heat into fluid flowing through the heater 80 is to have a large diameter heater with resistive wire 82 formed with a large pitch or depth of undulation. This maximises surface contact between fluid and the resistive wire 82 across a cross-section through the heater 80. However, there is a minimum radius for the resistive wire 82 as each undulation 84 must not touch an adjacent undulation. Thus, there is a central section 88 which is devoid of resistive wire 82. This leads to having a hot region H and a cool region C within the cross-sectional area of the fluid flow path. This translates into a temperature gradient along the fluid outlet 22 from the attachment 20. There is an outer ring of hot fluid and a central ring of cool fluid. At and adjacent the end 20a of the attachment 20 which is adjacent the fluid outlet 202 from the handle 210 the temperature of fluid will be at its’ hottest and the temperature will gradually reduce to a minimum at the end 20b of the attachment distal to the fluid outlet 212 from the handle 210.

The hot and cool fluid will also travel through the heater 80 at different velocities. The cool fluid has minimal restriction through the heater - due to friction from the surface of the former 86 whereas the hot fluid encounters more restriction due to interaction with the resistive wire 82 and an outer wall 180 which surrounds the heater 80. This difference in velocity along with the fact that the hot fluid is the outer ring of fluid exiting the fluid outlet 202 cause the temperature variance along the length of the fluid outlet 22 from the attachment 20.

In order to regulate the temperature of the fluid exiting the fluid outlet 22 of the attachment 20 along the length of the fluid outlet 22, the temperature profile at the fluid outlet 202 from the handle 210 must be changed. The inventors found that having a power dense heater with a relatively small pitch sandwiched between unheated zones provided better control of the temperature across the length of the fluid outlet 22 of the attachment 20. A first unheated zone 182 is at the centre of the heater 80 and a second unheated zone 184 is between the resistive wire 82 and the outer wall 180. This provides a temperature profile which whilst cooler at each end 20a, 20b of the attachment 20 has less variation than previously. Also having the hotter region near the centre of the attachment length is advantageous for styling and drying as more hair is exposed to the heated fluid.

In order to further improve the temperature characteristics of the attachment 20, the heater 80 does not have constant diameter. As a result of establishing that having a space between the resistive wire 82 and the outer wall 180 was advantageous, the inventors further realised that this space could be utilised to provide a greater diameter of heated fluid and to encourage mixing between cool fluid and heated fluid. Thus, the heater 80 has a first portion 110 which has constant diameter and a second portion 112 which extends toward the outer wall 180. In this embodiment, the first portion 110 is adjacent the fan unit 70 and the second portion 112 extends from the first portion 100 towards the fluid outlet 202 from the handle 210.

By extending the resistive wire 82 radially outwards towards the outer wall 180, the cool fluid flowing between the outer wall 180 and the first portion 110 i.e. in the first unheated zone 182 is forced to mix with the heated fluid. This provides a central cool region C, an intermediate hot region H and then an outer warm region W. The resulting temperature profile is flatter giving less variation long the length of the fluid outlet 22 from the attachment 20.

It is not just the temperature of the fluid that must be considered. Frictional losses and the temperature gradient through the appliance impact velocity causing a velocity gradient across the fluid outlet 202. As previously described, the central cool region C has less restriction through the heater 80 as the fluid only interacts with the former 86 and thermal safety devices. The fluid in the hot region H experiences more friction as the fluid passes around each winding of the resistive wire 82 thus, has a lower velocity than the fluid flowing through the cool region C. The outer warm region W has surface contact with the outer wall 180 and an outer surface of the resistive wire 82 in the first portion 110 but in the second portion 112 in addition to this, fluid flowing through the warm region W flows through some of the windings of the resistive wire 82. For this reason, the cross -sectional area of the warm region W is not necessarily the same as that of the central cool region C.

Referring to Figures 8a and 8b, features of the thermal safety system will now be discussed. There are three thermal safety devices an internal fuse 282, an exit fuse 284 and a bimetallic strip 286. The internal fuse 282 and the bimetallic strip 286 are provided within the heater 80 and are attached to the former 86 and this positioning is conventional. The bimetallic strip 286 is a first and resettable switch to cut power to the heater when it starts to overheat and the internal fuse 282 is a non-resettable circuit breaker which is rated to a higher temperature than the bimetallic strip 282.

As the internal fuse 282 is within the heater 80, it may not detect problems that occur between it and the fluid outlet 202 for that reason an exit fuse 284 is provided and it is provided across the face of the heater 80. In order to accurately locate the exit fuse 284 with respect to the heater the exit fuse 284 is initially assembled orthogonal to its final position. Referring to Figures 9a and 9b, in a first position 284a, the exit fuse 284 extends from connecting legs 286 away from heater 80 parallel, to a central axis of the heater. The connecting legs 286 are bent by 90° to place the fuse 284 in the operating position 284 b across a downstream face of the heater 80. This simplifies manufacture of the heater 80 and means the fuse can be positioned in the operating position 284b at the end of assembling the heater when all the windings of the resistive wire 82 are fixed in position.

Whilst the invention has been described with reference to a hot styling device, the rotatable connector can be used in any hand held appliance in which a relative rotation of the appliance with respect to a user occurs including, but not limited to straighteners and curling devices such as tongs, wands or irons. In these examples, as a fluid flow is not used in the styling process, the handle 210 would not include a fan unit but would include a heater or heated surface with which to style hair.

Claims

1. A hair care appliance comprising a housing, a fluid flow path extending from a fluid inlet into the housing to a fluid outlet from the housing, a heater extending at least partially along the housing wherein the heater comprises a heater element, a former around which the heater element is wound and an outer wall which extends around the heater element wherein the former provides a central region of the heater which is devoid of the heater element, the heater element provides an intermediate region which extends around the central region and the former provides an outer region extending between the intermediate region and the outer wall which is devoid of the heater element.

2. An appliance according to claim 1, wherein the appliance comprises an attachment which can be attached and removed from the appliance and the attachment comprises a second fluid flow path extending from a second fluid inlet which is in fluid communication with the fluid outlet of the housing and a second fluid outlet wherein the attachment extends along an axis and the second fluid outlet extends at least partially along the axis.

3. An appliance according to claim 2, wherein the axis along which the attachment extends is parallel to an axis along which the housing extends.

4. An appliance according to any preceding claim, wherein the heater comprises a region of constant diameter.

5. An appliance according to claim 4, wherein the region of constant diameter is positioned at an inlet end of the heater.

6. An appliance according to any preceding claim, wherein the heater comprises a region of varying diameter.

7. An appliance according to claim 6, wherein the region of varying diameter is positioned at an outlet end of the heater.

8. An appliance according to claim 6 or claim 7, wherein the diameter increases from the constant diameter to a larger diameter.

9. A hair care appliance comprising a housing, a fluid flow path extending from a fluid inlet into the housing to a fluid outlet from the housing, a fan unit extending at least partially along the housing wherein an inner flow guide is provided to direct fluid flowing through the fluid flow path to an inlet of the fan unit.

10. An appliance according to claims 9, wherein the inner flow guide comprises a curved surface that extends from the housing towards the fan unit.

11. An appliance according to claim 10, wherein the inner flow guide comprises fins that extend from the curved surface into the fluid flow path.

12. A hair care appliance comprising a housing, a fluid flow path extending from a fluid inlet into the housing to a fluid outlet from the housing, a fan unit extending at least partially along the housing wherein a further flow guide is provided to direct fluid flowing through the fluid flow path to an inlet of the fan unit.

13. An appliance according to claim 12, wherein the further flow guide extends from the housing towards the fan unit and curves around a portion of an inner diameter of the housing and curves between the housing and the fan unit.

14. An appliance according to claim 11 or claim 12, wherein the further flow guide forms part of a seal.

15. An appliance according to claim 14, wherein the housing comprises an inner wall extending within the housing which includes an enclosure for the fan unit and the seal comprises a first branch which extends around the inner wall adjacent the enclosure.

16. An appliance according to any preceding claim, wherein the seal further

5 comprises a second branch which extends from the first branch towards the housing.

17. An appliance according to any preceding claim, wherein the appliance is a hot styling device.