GB2625307A

GB2625307A - Heater

Info

Publication number: GB2625307A
Application number: GB2218746.2A
Authority: GB
Inventors: Nicholas Edwards Robert
Original assignee: Dyson Technology Ltd
Current assignee: Dyson Technology Ltd
Priority date: 2022-12-13
Filing date: 2022-12-13
Publication date: 2024-06-19
Also published as: GB202218746D0; WO2024127157A1

Abstract

A fin 100, 500a-d for dissipating heat from a heater element 152, 552 of a heater, the fin comprising a foot portion 102, 502 to attach to the heater element and a leg portion 106, 506 coupled to and extending away from the foot portion, the leg portion of the fin comprising a compressible portion 110, 510 between the foot portion and a distal end of the leg portion. The compressible portion may be coupled to the foot portion. The leg portion may comprise a dissipation body that extends in a first plane, the foot portion extends in a second plane different from the first plane, and the compressible portion comprises a first portion that extends in a further plane different to the first plane.

Description

HEATER

Technical Field

The present invention relates to a fin for dissipating heat from a heater element of a heater, and a method of manufacturing a heater thereof

Background

Heaters used in devices for heating a fluid such as air or a liquid typically include a heater element for providing the heat and a plurality of metallic fins for dissipating this heat into the fluid. The fins may have a generally L-shaped configuration with the bottom portion being pressed onto the heater element and then attached thereto by brazing, for example, using a placement system. Where the placement system is employed to attach plural fins to the heater element in one operation, it is desirous for the heater element to have a relatively flat surface to allow for a relatively even and equal application of pressure by the placement system to cause each fin to attach firmly to the heating element. In order to flatten the surface of the heater element prior to application of the fins, it is known that heater elements may undergo a smoothing process such as sintering or lapping. This step can increase manufacturing cost and time.

Summary

According to a first aspect of the present invention, there is provided a fin for dissipating heat from a heater element of a heater, the fin comprising a foot portion to attach to the heater element and a leg portion coupled to and extending away from the foot portion, the leg portion comprising a compressible portion between the foot portion and a distal end of the leg portion.

A fin having a compressible portion can improve reliability in a manufacturing process that employs a placement system to attach the fin to the heater element. For instance, the compressible portion may compress by a different amount, during attachment of the foot portion to the heater element, in dependence upon the flatness of the heater element.

For example, for a given force applied to the compressible portion, to urge the foot portion of the fin against the heater element during attachment (e.g. by brazing), the compressible portion can compress more, if the heater element is slightly closer to the placement system, or less, if the heater element is slightly further away from the placement system, thereby to account for variations in the flatness of the heater element. In addition, or alternatively, the presence of the compressible portion may mean that, for a given distance between the placement system and the heater element, the force generated between the foot portion and the heater element can be generally of a similar magnitude irrespective of whether a surface of the heater element is marginally higher or lower, relative to the position of the placement system, than anticipated. Moreover, a fin having a compressible portion may influence tolerance requirements of other aspects of the manufacturing process, thereby leading to cost reductions. For example, heater elements may not need to be as flat, and manufacturing steps that would otherwise be employed to increase heater element flatness may not be needed. In addition, or alternatively, placement systems may be simpler. For example, placement systems may need fewer (or no) sensors to sense differences in heater element flatness and/or differences in forces applied to difference fins at different heater element locations duri ng attachment.

The compressible portion may also reduce the risk of unwanted deformation to the leg portion during manufacture, for example, when a force is applied to urge the foot against the heater element. In that case, any excess force may be absorbed by the compressible portion. Since the leg portion may provide the majority of the surface area upon which heat dissipation to the surroundings can occur this may lead to improved heaters being manufactured. The compressible portion may itself also dissipate some heat, by virtue of being part of the leg portion. However, the remaining extension of the leg portion may provide a large surface area in comparison to the compressible section.

The leg portion and the compressible portion may be one integral piece with separate functions. In other words, the compressible portion may be an area of the leg portion configured to be compressed, whereas the remaining leg portion may remain uncompressed.

The compressible portion may be coupled to the foot portion. Coupling the compressible portion and the fin portion positions the compressible portion close to the portion of the fin which is attached to the heater element. As such, the forces for urging the foot against the heater element may be closer to the foot portion.

The leg portion may comprise a dissipation body that extends in a first plane, where the foot portion extends in a second plane different from the first plane, and the compressible portion comprises a first portion extending in a further plane different the first plane. The dissipation body may provide the main surface area to dissipate the heat. To this end, the dissipation body may be relatively longer than the compressible portion of the fin. Having a portion of the compressible body extend in a different plane to that of the dissipation body may provide a surface upon which the compression force can act. This may protect the dissipation body from buckling or other forms of deformation which could reduce surface area and therefore effectiveness of a heater.

Further, at least part of the compressible portion may protrude away from the plane of the dissipation body. In some examples, the compressible section may protrude from 0.1mm to 1.6mm from the plane of the dissipation body at a maximum distance. The maximum distance of this protrusion may therefore dictate a footprint of the fin. This may be advantageously smaller than in the footprint of fins in the prior art through the use of a compressible portion allowing for an improved attachment of the fin to the heater substrate.

Optionally an angle between the first plane and the second plane is greater than an angle between the second plane and the further plane. In some examples, the angle between the second plane and the further plane is less than 10 degrees. In some examples, the second plane and further plane are approximately parallel to one another, such that the angle between them is approximately zero. By having the extensions of the foot portion and the first portion correspond, the force applied to the compression portion may be substantially linear. This may make manufacture of a heater simpler and easier. In some examples the foot portion and first portion may be positioned parallel and or in line with one another, with a second portion spacing them apart. The second portion may extend from the first portion in the same plane as the dissipation body such that the foot portion is arranged below first portion. This may reduce the footprint of the fin, allowing for more fins per unit area on the substrate, which can improve the efficiency of the end heater.

Optionally, the compressible portion comprises a profile having at least one curve. Having a curve in the profile may help to distribute a compression force more evenly about the compressible portion. This may help to distribute stress between the second portion and the first portion and/or the foot portion. In some examples, the first and foot portions coupled by the second portion form a flattened C-shaped profile. Of course, other curved profiles of the second portion, for example to form an S-shape, are envisaged. The dissipation body may curve towards the first portion. This may reduce stresses at the join between the first portion (which receives the force) and the leg portion, which does not experience a direct application of force.

Optionally, one or both of the first and foot portions comprise a profile having a substantially flat section. A flat section may allow for improved engagement between the placement system and the first portion, or between the foot portion and the heater element. That is, the flat section may allow a more even contact between the placement system and the first portion or between the foot portion and the heater element. Optionally the fin comprises a metallic material. Metallic materials may comprise a level of ductility which may make forming the fin to have a compressible section easier. To this end, the compressible section may be stamped into the fin ahead of brazing. In addition, metallic materials have a high thermal conductivity, which is advantageous for distributing heat.

According to a second aspect there is provided a heater comprising a heater element and a fin as described above.

Optionally the heater comprises a further fin comprising a leg portion coupled to and extending away from a foot portion, and a compressible portion between the foot portion and a distal end of the further leg portion. Multiple fins may provide a large surface area to act as a heatsink for dissipating heat thus increasing the effectiveness of the heater. The heater may of course have a plurality of these fins, with more fins increasing the available surface area for heat dissipation. These fins may have different heights, for example respective dissipation bodies may have different length extensions.

This may allow the overall cross section of the heater to be shapable to fit into various components, for example tubes and pipes. Each of the fins may have an identical compressible portion, regardless of the height of the distribution body.

In some examples, the heater may comprise a plurality of individual fins, coupled together to form a dissipation element. The dissipation element may therefore comprise a plurality of fins, each with a respective compressible section. A first fin may be coupled to a further fin at the respective distal ends by a foot portion or top portion. In this way, the plurality of fins may together form the dissipation element which has a generally zigzag, wavelike, or sinusoidal profile. In this example, each upper region or peak corresponds with a distal end of two neighbouring/adjoining fins (e.g., fins 1 and 2 in series) and each trough corresponds with a foot shared by neighbouring/adjoining fins (e.g. fins 2 and 3 in series). This may be easier to manufacture than individual fins. A coupling between adjacent fins may itself have a compressible portion between the respective distal ends. This additional compressible portion may further protect the fins from warping etc when the force is applied. As such each fin may include a compressible portion as described above and in some examples each fin may have a plurality of compressible portions (i.e., the additional compressible portion).

The compressible portion of the fin and the compressible portion of the further fin may have an identical profile. Having identical profiles for the compressible portion of each of the plurality of fins may allow for substantially equal compression of the fins during forming the heater or different degrees of compression due to variations in flatness of the surface of the heater. Respective dissipation bodies may also be identical, but in other cases may include variations. For example, the dissipation bodies may vary in height such that the heater can be shaped for optimal heat dissipation and to fit into pipes etc. The respective fins may be arranged on the heater element such that each compressible portion is oriented facing the same way. Resultingly, the plurality of fins may compress uniformly across the heater element. This may reduce the risk of a fin contacting an adjacent fin when the compressible portion is compressed. Alternatively, the first and further fin may be arranged in a mirror configuration.

Optionally, the leg portion of the fin is less than 200 micrometres (pm) from the leg portion of the further fin.

Arranging the fins close to one another allows for a higher maximum number of fins, and so surface area for dissipating heat can be optimised. In cases where the heater has a plurality of fins, the plurality of fins may be spaced equidistantly from one another which may give a substantially uniform heating profile across the heater.

According to a third aspect of the invention the is provided a hair care appliance comprising the heater as described above.

According to a fourth aspect of the invention there is provided a method of manufacturing a heater, the method comprising: providing a fin comprising a foot portion and a leg portion coupled to and extending away from the foot portion, the leg portion comprising a compressible portion between the foot portion and a distal end of the leg portion; applying a force to the fin to urge the foot portion against a heater element, wherein the force is applied via the compressible portion; and while the force is applied, attaching the foot portion and the heater element together.

As described above, applying a force to the fin and thereby compress the compressible portion during a heater manufacturing process may improve reliability in that manufacturing process. That is, the foot may be more easily urged against the heater element via the compression of the compressible element. There may be a particular improvement when a placement system is used. For instance, the compressible portion may compress by a different amount, during attachment of the foot portion to the heater element, in dependence upon the flatness of the heater element.

The heater element may comprise a ceramic material for example, aluminium nitride, alumina, or silicon nitride, or a combination thereof The heater element may be a heat conducive element or in some cases may envelope a heat conductive element therein. As such, in use, the heater works by heating the heater element which transfers the heat to the fin for dissipation into the surroundings. The connection between the heater element and the foot (and by extension the fin) is thus an important factor in providing an efficient and effective heater. The step of compressing the compressible portion may therefore improve the connection and so efficiency and effectiveness of the heater.

Brazing the fin and the surface of the heater element may include placing the fin and heater element in a furnace at a temperature of between 550°C and 900°C. Optionally, the force is applied via a placement system. Using a placement system may allow for greater control of the compression force and or compression of the compressible fin. Further, the placement system may maintain the compression force during brazing, which may result in improved joining of the fin to the surface of the heater element. The placement system may be adapted to correspond to the shape of the compressible fin such that the placement system can provide a uniform compression force across the first portion.

Optionally, the method comprises applying the force until a flange, that approaches the heater element as the force that is applied to the fin increases, contacts the heater element. The method then comprises maintaining the placement system in that position while attaching the foot portion and the heater element together. The flange may be a projection extending from a main body of the placement system for example. The projection may therefore form a stopping mechanism to prevent over compression of the compressible section of the fin.

Optionally, the method further comprises arranging the placement system such that a dissipation body protrudes into and/or through a cavity of the placement system. In this way, the force is not applied to an upper region of the fin. By, for example, applying the compression force on only the compressible portion, the portion of the heater which dissipates the majority of the heat, the dissipation body, may be protected from any forces which could cause deformation or other damage.

Optionally, the method further comprises applying a braze filler to a surface of the heater element, and wherein attaching the foot portion and the heater element together comprises brazing. The braze filler may melt during the brazing process and cause the filler and the surface of the heater element to react together to attach the foot portion of the fin to the surface of the heater element. In this way, the braze filler may provide a medium for attaching the fin to the surface of the heater element. The braze filler may also fill in any spacing between the foot portion and the heater element. As discussed above, using a compressible section in the fin can allow for better contact between the fin and the surface of the heater element, which may require less braze filler to fill any gaps This may save on material costs during the manufacturing process and also reduce the chance of the braze filler wicking upward in the extension direction of the leg portion. Further, the placement system contacts the fin on the compressible portion, which is spaced apart from the heater element. For comparison, previous placement systems would contact a foot of an L-shaped fin, which is closer to the heater element. The compressible section may therefore allow for the placement system to apply the compression to the fin at a greater distance from the heater element than in previous manufacturing methods. As such, even if some braze filler wicks up the leg portion there is a reduced chance of the braze filler reaching the placement system. This therefore reduces the chance of the placement system erroneously becoming brazed to the heater during the brazing process.

The braze filler may be an alloy including silver, copper, and titanium. For example, the alloy is formed from an initial composition of 72% silver and 28% copper to which 1-5 weight % titanium is added. The titanium may increase reactivity and reacts with the surface of the heater element forming complex inter-metallic phases. The braze filler may at least partly adhere the fin to the surface of the heater element and then, upon brazing provide a fixed coupling therebetween.

Optionally the method further comprises providing a further fin comprising a foot portion and a leg portion coupled to and extending away from the foot portion, the leg portion comprising a compressible portion between the foot portion and a distal end of the leg portion; applying the force to the further fin to urge the foot portion against the heater element, wherein the force is applied via the compressible portion; and while the force is applied, attaching the foot portion and the heater element together.

A plurality of fins allows for the heater to effectively exchange heat with an external environment. The force may be applied to the respective compressible portion of each of the fin and the further fin simultaneously. The compression simultaneously may be achieved using one placement system for example. Simultaneous compression of the plurality of fins may speed up the manufacturing process. In these examples, the placement system may have one or more flanges to prevent over compression of the fins. The flanges may be spaced about the placement system to provide multiple stopper areas.

Optionally, the fin and further fin are provided on a first side of the heater element, and the method further comprises providing an additional fin and additional further fin on an opposite side of the heater element to the first side. The second fin may be identical to the fin described above. Having two (or more) fins on each side of the heater element may allow for a heater element to have a bar-like form with fins on either side, thereby maximising the surface area of the final heater. This may provide an efficient heater.

Optionally, the method comprises providing a plurality of first and further fins.

According to a fifth aspect there is provided a placement system for use in the method. The placement system may comprise a clamp or jig for example.

Further features and advantages of the invention will become apparent from the following description of preferred embodiments of the invention, given by way of example only, which is made with reference to the accompanying drawings.

Brief Description of the Drawings

Figure la is a schematic diagram that shows a side profile view of a heater, according to an example of the present invention; Figure lb is a schematic diagram that shows a perspective view of the heater of Figure 1 a; Figure lc is a schematic diagram that shows components of Figure la being assembled; Figure 2 is a flow diagram that shows a method of forming a heater,according to an example of the present invention; Figure 3 is a schematic diagram that illustrates how a degree of compression can vary between two fins as they are urged against a non-flat the heater element, according to an example of the method of Figure 2; Figure 4a is a schematic diagram that shows a heater with a first and second plurality of fins, respectively, being attached to first and second sides of a heater element, and a placement system that is performing the attaching, according to an example of the present invention; Figure 4b is a schematic diagram that shows the heater of Figure 4a with the placement system removed, according to an example of the present invention, and Figure 5 is a schematic diagram that shows a further example of a fin arrangement according to an example of the present invention.

Throughout the drawings arid description like reference numerals refer to like parts.

Detailed Description

Referring now to Figure 1 a and lb a heater 50 according to an example is illustrated. The heater 50 has a fin 100 attached to a surface 152 of a heater element 150 so as to dissipate heat, generated by the heater element 150, to an external environment.

To this end, the fin 100 comprises a metallic material, which has a high thermal conductivity. The fin 100 has a thickness of 0.1min to 0.3mm.

The heater element 150 comprises a ceramic material, which envelops a metallic heat member (not shown). The construction of the heater element is not pertinent to the invention, and so will not be described in any further detail herein.

The fin 100 is attached to the heater element 150 via a foot portion 102. The foot portion 102 is profiled and arranged to be in contact with the surface 152 of the heater element 150. In order to facilitate a strong attachment between the foot portion 102 and the surface 152, the foot portion 102 has a profile which has a substantially flat section 104. This flat section 104 corresponds to the surface 152 of the heater element 150, which is at least partly flat. In other words, part of the foot portion 102 (i.e., the flat section 104) and the surface 152 of the heater element 150 extend along parallel planes. In this example, the foot portion 102 has a width W of around 0.1mm and a length L of around 0.1 mm(other dimensions are envisaged). The foot portion 102 has a footprint which allows for heat transfer from the heater element 150 to the fin 100.

Extending away from the foot portion 102, the fin 100 also has a leg portion 106. The leg portion 106 provides a surface which dissipates the heat from the heater element 150. To this end, the leg portion 106 has a dissipation body 108 which extends in a plane perpendicular to the plane in which the foot portion 102 extends. Resultingly, the dissipation body 108 is substantially perpendicular to the surface of the heater element 150 and has a relatively long extension to provide as much surface area as possible within whatever space is available.

Between the leg portion 106 and the foot portion 104 there is a compressible portion 110. The compressible portion 110 couples the leg portion 106 to the foot portion 102. The compressible portion 110 has a first portion 112, which extends away from the dissipation body 108 of the leg portion 106. As illustrated, in this example, a plane in which the first portion 112 extends is substantially perpendicular to the plane in which the dissipation 108 body extends. In other words, at least part of the compressible portion 110 protrudes away from the dissipation body 108.

The first portion 112 is spaced apart from and substantially parallel to at least the flat section 104 of the foot portion 102. The first portion 112 is also in line with the foot portion 102, in so much as at least part of the first portion 112 is directly above at least part of the foot portion 102.

To couple the first portion 112 to the foot portion 110 the compressible portion 110 also includes a second portion 114. This second portion 114 curves away from the plane of the dissipation body 108, and a mid-section of the curve has a tangent that is generally parallel to the dissipation body 108.

As shown in Figure la, the first, second and foot portions have a smooth and curved profile such that they together form a flattened C-shape. The compressible portion 110 may be formed by stamping a desired profile, in this case the described flattened C-shape, into a copper or aluminium sheet which then forms the fin 100.

One method of attaching the foot portion 102 to the heater element 150 to assemble the heater 50 is shown schematically in Figure lc and as a flow chart in Figure 2 The surface 152 of the heater element 150 is coated in a braze filler 154. In this example, the braze filler 154 is a silver alloy with an initial composition of 72% silver and 28% copper to which 1-5 weight % titanium is added.

In a first step S200, a fin 100, for example of the kind described above, is provided. The foot portion 102 of the fin 100 is positioned on the braze filler 154 on the surface 152 of the heater element 150. The braze filler 154 acts as an adhesive to help retain the foot portion 102 against the fin 100 on the surface 152 of the heater element 150 during this assembly.

A force 170 is applied by a placement system 172 to the fin 100 in step S202. The force 170 is applied to the compressible portion 110 in a direction towards the surface 152 of the heater element 150. The first portion 112 of the compressible portion 110 receives the force 170. As the first portion 112 protrudes away from the dissipation body 108 the force 170 is applied away from the dissipation body 108 as well. The force 170 is transmitted to the foot portion 102 through the compressible portion 110 in order to urge the foot portion 102 against the heater element 150. The force 170 compresses the compressible portion 110 by a certain amount so that the first portion 112 moves toward the foot portion 102. The compressible section 110 is deformed by the applied force 170. More particularly, the C-shape of the compressible portion is compressed or squashed by a certain amount as the force is applied to the first portion 112.

The placement system 172 comprises an external structure which is shaped to push against the first portion 112 of the compressible portion 110. In this example, the placement system 172 comprises a clamp. The shape of the placement system 172 corresponds to the shape of the fin 100. In this way, the placement system 172 is shaped such that it does not apply pressure to the dissipation body 108 when urged against the fin 100.

During the urging of the foot portion 102 against the heater element 150, the braze filler 154 can be slightly displaced and wick upwards around the foot portion 102.By applying the force 170 to the compressible portion 110, rather than directly to the foot, the placement system 172 is less likely to come into contact with and/or become contaminated by the braze filler 154 The placement system 172 maintains the force 170 on the compressible portion 110 as the heater element 150 and fin 100 are heated. This heating is achieved by placing the heater element, fin 100 and placement system 172 (assembled as described) into a brazing furnace at approximately 900°C. The high temperature causes the braze filler 154 to react with the surface 152 of the heater element 150. This reaction attaches the foot portion 102 of the fin 100 to the surface 152 of the heater element in step S204 in a known way. The foot portion 102 is attached along the flat section 104. Once removed from the brazing furnace, the placement system 172 is removed. The heater 50 can then be placed into various devices such as a hair care appliance.

Figure 3 shows a first fin 300a and a second fin 300b mounted on a heater element 350, which has an uneven surface. The first and second fins 300a,b are of substantially identical construction to the fin 100 described above. In practice, the heater element 350 may have an uneven surface 352, for example, because of thickness variations, warping or surface undulations. In any event, the potential unevenness has been exaggerated in Figure 3 for the purposes of illustration. As shown, the surface 352 has a section 352a which is in a different plane to a further section 352b: the section 352a is lower in the figure than the further section 352b.

Due to the unevenness of the surface 352, the foot portion 302a of the first fin 300a is on a different plane to a foot portion 302b of the second fin 300b. A placement system 372 applies a force 370 towards the heater element 350. Accordingly, respective compressible portions 310a,b of each fin 300a,b are compressed. The compressible portions 310a,b compress by different amounts due to the unevenness of the surface 352. As shown, the second fin 300b is compressed more than the first fin 300a. The resulting deformation is concentrated in the compressible portions 310a,b. That is, the distance between the first portion 312b of the second fin 300b and the respective foot portion 302b is less than the distance between the first portion 312a of the first fin 300a and the respective foot portion 302a. Meanwhile, the lengths of the dissipation bodies 308a,b of the fins remain unaffected. As such, the same amount of compression force 370 applied via the placement system 372 to the first and second fins 300a,b compresses the compressible portions 310a,b differently to compensate for the uneven surface 352.

As shown in Figure 3, the placement system 372 comprises a jig 371 to support and apply pressure to the fins 300. More particularly, the jig 371 has recesses or cavities 374, in which the dissipation bodies 308 are contained, and projections or pressure regions 376, which contact with and apply pressure to the first portions 312 of the fins. In this example, the cavities 374 are sized and configured so that downward pressure is not imparted to the dissipation bodies 308 of the inserted fins 300 as the force is applied to the first portions 312. Put another way, the pressure regions 376 of the placement system 372 slots between adjacent distribution bodies 308 and applies the force 370 directly to the compressible portions 310.

Figure 4a illustrates an example of a heater 54 with a first plurality of fins 480.

Individual fins 400 have been described above, and so will not be described again here for brevity. The first plurality of fins 480 are positioned on a surface 452 of a bar shaped heater element 450.

The plurality of fins 480 are each equidistantly spaced apart along a length of the surface 452. In this way, the plurality of fins 480 are positioned along a surface 452 of the bar-shaped heater element 450. The distance by which adjacent fins are spaced apart, when taken between two distribution bodies 408 of adjacent fins, is about 0.8mm to 1.6mm. Although not shown, each individual fin 400 also extends to cover substantially all of a width of the surface 452 of the heater element 54. Other examples may have a further plurality of fins spaced apart behind those shown. The plurality of fins 480 therefore covers a large area of the surface 452 of the heater element 450.

The heater element 450 has a second surface 453 which is opposed to the surface 452 above. This second surface 453 has a second plurality of fins 482. The second plurality of fins 482 are a mirror image of the first plurality of fins 480, such that the heater 54 has a line of symmetry along a central longitudinal axis of the heater element 450.

There is a first and second placement system 472, 473 similar to that described above. These placement systems 472, 473 apply a force which clamps each of the first and second plurality of fins 480, 482, onto the surface 452 of heater element 450. The placement systems 472, 473 each have a plurality of cavities 474, 475 corresponding to a dissipation body 408 of each individual fin 400. In this example, the cavities 474, 475 are sized and configured so that pressure is not applied to any dissipation body 408 of the first and second pluralities of fins 480, 482 as the force is applied.

Each placement system 472, 473 also has a flange 478, 479. This flange 478, 479 is to prevent the placement system 472, 473 over-compressing the first and second plurality of fins 480, 482. To this end, the flanges 478, 479 protrude outwardly from the rest of the placement systems 472, 473. That is, the flanges 478, 479 extend from a jig 471 of the placement systems 472, 473 further than a pressure region 476. The pressure region 476 being the same as that described above, for contacting the compressible portion 410 of each of the fins 400. In this way, when applying the force toward the heater element 450, the placement systems 472, 473 are pushed towards the heater element 450 until the respective flange 478, 479 contacts the surface 452, 453.

This contact causes the placement systems 472, 473 to stop pushing any further toward the heater element 450.

As shown, the surface 452 is uneven, in that it includes a protuberance 484 and a depression 486 (these are illustrated in exaggerated form for the purpose of explanation). A fin 400 which is positioned on either of the protuberance 484 or depression 486 is compressed in the same manner as described in reference to Figure 3, in that a compressible portion 410 of that fin 400 absorbs any height difference of the surface 452. In the example shown by Figure 4a, all compressible portions 410 of the pluralities of fins 480, 482 are each compressed, but to different amounts at the protuberance 484 and at the depression 486. Once the placement systems 472, 473 are removed after brazing, as shown in Figure 4b, each fin 400 remains compressed. So, the respective fins 400 at the protuberance 484 and the depression 486 remain in a different state of compression to the other fins even when the placement systems 472, 473 are removed.

Turning now to Figure 5, an alternative example is illustrated, in which a plurality of fins 500a-d are coupled together forming a single dissipation element 590.

The dissipation element 590 in this example has a generally sinusoidal profile, with each fin 500 making up a peak and trough. The dissipation element 590 extends along a length of a heater element 550, and is attached to the heater element 550 at a plurality of points.

Considering individual fins 500a-d, a single fin 500b has a foot portion 502 which is positioned on the surface 552 of the heater element 550. In this example, the foot portion 502 corresponds to a trough of the sinusoidal profile.

Extending away from the foot portion 502 is a leg portion 506. The leg portion 506 extends up to a top portion 509 at a distal end of the fin 500b. The top portion 509 corresponds to the peak of the sinusoidal profile. The leg portion 506 couples to the top portion 509 at a first side, and extending from an opposite side of the same top portion 509 is a leg portion 506 of a further fin 500c. This leg portion 506 of the further fin 500c extends down to another foot portion 502. This foot portion 502 is also on the surface 552 of the heater element 550. The fins 500b and 500c are thus adjacent fins 500b,c. These adjacent fins 500b,c are mirror images of one another.

A plurality of fins 500a-d repeat this pattern to form a continuous profile of the dissipation element 509. A fin 500a-d therefore has a common foot portion 502 and common top portion 509 with adjacent fins. As such, each fin 500a-d is joined to its adjacent fins. In this example, the top portion 509 of each fin 500a-d is also the same height along the length of the dissipation element 590. The foot portions 502 and top portions 509 have curved profiles which gives the dissipation element 590 a substantially sinusoidal appearance.

In this example, each of the fins 500a-d has two compressible portions 510 which protrude away from the leg portion 506. The two compressible portions are therefore between the foot portion 502 and top portion 509 of each fin 500a-d. In this example, the two compressible portions 510 protrude from the leg portion 506 in opposite directions to one another. The compressible portions 510 are similarly shaped to those described above, with a protrusion away from a body 508 of the leg portion 506. In this example each compressible portion 510 has a curve 511 that returns back to the leg portion 506.

To attach the fins 500a-d to the heater element 550 a placement system 572 applies a force 570 to the top portion of each fin 500a-d. In this example, the placement system 572 has a substantially planar surface which contacts each top portion 509. The force 570 from the placement system 572 is transmitted down the leg portions 506 to respective compressible portions 510. This means the compression of the fin 500a-d is limited to being within the compressible portions 510 of that fin 500a-d.

When the force 570 is applied, the compressible portions 510 compress, which changes the overall length of the leg portion 506. The compression is within the compressible portions 510, such that the body 508 of the leg portion 506 does not compress or warp. This change in length absorbs any unevenness in the surface 552 of the heater element 550 because the compressible portions 510 will compress by different amounts based on the surface 552 flatness of the heater element 550.

As described above with reference to Figure 2 the placement system 572 remains clamped down on the fins 500a-d as they are placed into a braze furnace. Although not shown, braze filler is applied to the surface 552 of the heater element 550 prior to brazing. Each foot portion 502 is thus attached to the heater element 550 by a brazing process. Once brazed, the placement system 572 can be removed from the final heater. Similarly to Figure 4b, the heater element 550 may have a further dissipation element (not shown) on an opposing side to the side shown with the dissipation element 590, so that the heater element 550 is between two dissipation elements.

The above embodiments are to be understood as illustrative examples of the invention. Further embodiments of the invention are envisaged. For example, although illustrated as directly adjacent to the foot portion it is envisaged that the compressible portion may be spaced apart from the foot portion. In other words, the leg portion may have two sections either side of the compressible portion, with one of these sections being coupled to the foot portion. This may give the fin a t-shaped profile for example. Although illustrated as substantially planar the dissipation body of the leg portion of the fin may have some slight curvature or undulation (to give additional surface area), to this end a plane of extension should be considered as the average direction of extension.

Although the compressible portion arid foot portion are illustrated throughout as having a C-shaped profile, it should be understood that the profile may include further compressible shapes, for example S or Z shaped profiles.

It is envisaged that the dissipation bodies of a heater may be different extension lengths dependent on the intended use of the heater. For example, the dissipation bodies may be of shorter extension lengths towards ends of a bar shaped heater element. This can then give a circular cross-section of the heater, which may fit into tubes for example. While described as generally identical, there may also be some differences in the fin construction, other than just distribution body length. For example, fins may be arranged such that the compressible portion protrudes in different directions to that shown and or adjacent fins. Further, although the pluralities of fins are described as min-or images (such that in the images they face the same way), in other examples, the first and second plurality of fins may be rotated versions of one another (so they face opposite directions). Also, some minor variation in form may occur, for example during the manufacturing of the fins.

It is to be understood that any feature described in relation to any one embodiment may be used alone, or in combination with other features described, and may also be used in combination with one or more features of any other of the embodiments, or any combination of any other of the embodiments. Furthermore, equivalents and modifications not described above may also be employed without departing from the scope of the invention, which is defined in the accompanying claims.

Claims

CLAIMSA fin for dissipating heat from a heater element of a heater, the fin comprising a foot portion to attach to the heater element and a leg portion coupled to and extending away from the foot portion, the leg portion comprising a compressible portion between the foot portion and a distal end of the leg portion 2. The fin of claim 1, wherein the compressible portion is coupled to the foot portion 3. The fin of claim 2, wherein the leg portion comprises a dissipation body that extends in a first plane, the foot portion extends in a second plane different from the first plane, and the compressible portion comprises a first portion that extends in a further plane different to the first plane The fin of claim 3, wherein an angle between the first plane and the second plane is greater than an angle between the second plane and the further plane.5. The fin of claim 4, wherein the compressible portion comprises a profile having at least one curve.The fin of any of claims 3 to 5, wherein one or both of the first and foot portions comprise a profile having a substantially flat section.The fin of any preceding claim, wherein the fin comprises a metallic material.A heater comprising a heater element and a fin as claimed in any of claims Ito 7.The heater of claim 8, wherein the heater comprises a further fin comprising a leg portion coupled to and extending away from a foot portion, and a compressible portion between the foot portion and a distal end of the further leg portion.10. The heater of claim 8 or 9, wherein the compressible section of the fin and the compressible section of the further fin have an identical profile.11. The heater of any of claims 8 to 10, wherein the leg portion of the fin is less than 200 micrometres from the leg portion of the further fin.The heater of any of claims 8 to 11, wherein the first fin is coupled to the further fin at the respective distal ends.A hair care appliance comprising the heater of any of claims 8 to 12.A method of manufacturing a heater, the method comprising: providing a fin comprising a foot portion and a leg portion coupled to and extending away from the foot portion, the leg portion comprising a compressible portion between the foot portion and a distal end of the leg portion; applying a force to the fin to urge the foot portion against a heater element, wherein the force is applied via the compressible portion of the fin and causes at least some compression of the compressible portion, and while the force is applied, attaching the foot portion and the heater element together.The method of claim 14, wherein the force is applied by a placement system.The method of claim 15, wherein the placement system comprises a flange that approaches the heater element as the force that is applied to the fin increases, the method comprising increasing the force until the flange contacts the heaterS 13. 14. 15. 16.element, and then maintaining the placement system in that position while attaching the foot portion and the heater element together.17. The method of claim 15 or 16, further comprising arranging the placement system such that a dissipation body protrudes into and/or through a cavity of the placement system.18. The method of any of claims 14 to 17, further comprising applying a braze filler to a surface of the heater element, and wherein attaching the foot portion and the heater element together comprises brazing.19. The method of any one of claims 14 to 18, further comprising: providing a further fin comprising a foot portion and a leg portion coupled to and extending away from the foot portion, the leg portion comprising a compressible portion between the foot portion and a distal end of the leg portion; applying the force to the further fin to urge the foot portion thereof against the heater element, wherein the force is applied via the compressible portion of the fin and causes at least some compression of the compressible portion; and while the force is applied, attaching the foot portion and the heater element together.20. The method of claim 19, wherein the force is applied to the respective compressible portion of each of the fin and the further fin simultaneously.21. The method as claimed in any of claims 19 or 20, wherein the fin and further fin are provided on a first side of the heater element, and wherein the method further comprises providing an additional fin and additional further fin on an opposite side of the heater element to the first side.22. The method as claimed in any of claims 19 to 21, wherein the method comprises providing a plurality of first and further fins 23. A placement system for use in the method of claims 16 to 22.