Hair care appliance

Abstract

A hair care appliance 100 comprising an airflow generator 110 configured to direct air along an airflow pathway 124 towards a user in use, and a thermoelectric cooler (TEC) module 112 with a first side 114 for absorbing heat and a second side 116 for emitting heat, wherein at least the first side is in thermal communication with the airflow pathway for absorbing heat from the air in the airflow pathway to cool the air directed towards the user in use. The airflow pathway may comprise a first branch (226, fig.3) and a second branch (228, fig.3), where a heater 120 is in thermal communication with the second branch. In response to a user input selecting a first temperature or a second temperature higher than the first, a controller 122 may adjust the power to the heater and the TEC module and transition a diversion mechanism (234, fig.3) at a joint segment (232, fig.3) between a first configuration directing air along the first branch and a second configuration directing air along the second branch. The TEC module may absorb heat from the air in the first branch and emit heat to the air in the second branch.

Description

BACKGROUND It is known for a hair dryer to have a plurality of temperature settings for varying the temperature of a heater that heats airflow through the hair dryer. It is also known for a hair dryer to include a “cold shot” setting which, when selected, turns off the heater so that the hair dryer provides cooler airflow. The cold shot may be used to set hair into a particular style. SUMMARY According to a first aspect of the invention, there is provided a hair care appliance comprising: an airflow assembly comprising an airflow generator and an airflow pathway, the airflow generator being configured to direct air along the airflow pathway towards a user in use; a thermoelectric cooler, TEC, module having a first side for absorbing heat and a second side for emitting heat, at least the first side of the TEC module being in thermal communication with the airflow pathway for absorbing heat from the air in the airflow pathway to cool the air that is directed towards the user in use. The TEC module helps to cool down the air in an active manner. This may provide an advantage over existing appliances which rely only on passive cooling (by turning off the heater and blowing unheated air over the heater). In these passive arrangements, even after the heater is turned off, the thermal mass of the heater limits the rate at which the airflow can be cooled, and the power consumption of the hair appliance (e.g. a motor thereof) contributes heat that limits the minimum temperature that can be reached. By implementing a TEC module in thermal communication with the airflow pathway, hair care appliances actively absorb heat from the air in the airflow pathway, thereby supporting a quicker reduction in temperature and / or allowing the airflow to reach cooler temperatures than those of existing appliances. For example, appliances can even reach temperatures below room temperature, which can be particularly desirable for users in hot climates (e.g. Asia) who often find the excess heat from hair dryers uncomfortable, and may often use the “cold shot” setting purely as a means for cooling down their body temperature. As used herein, the term “hair care appliance” may refer to any appliance for providing airflow to hair. For example, the hair care appliance may be embodied as a hair dryer, airflow straightener, airflow curler, or multi-styler. As used herein, the term “thermoelectric cooler” or “TEC” takes its usual meaning to refer to a solid-state active heat pump which transfers heat from one side of the device to the other (i.e. from the first side to the second side) when electrical energy is applied to the TEC module, e.g. to a semiconductor layer between the first and second sides. The semiconductor layer may also be referred to as a “central zone” or “central layer”. The “first side” of the TEC module may also be referred to as a “cold side” or “heat-absorber side”. The “second side” of the TEC module may also be referred to as a “hot side”, “heatemitter side”, or “heat-rejector side”. It will be appreciated that the temperatures of these sides will vary in use (e.g. in dependence of an amount of power supplied to the TEC module), and thus the terms “cold side” and “hot side” are used purely as labels to relate to the relative temperature between these two sides when power is supplied to the TEC module. When no power is supplied to the TEC module, the two sides may be in thermal equilibrium, or the “cold side” could be hotter than the “hot side”. The airflow generator may include a fan and a motor configured to move (rotate, spin) the fan to direct air along the airflow pathway. The appliance may include means for supplying power to the TEC module. The means for supplying power may comprise a battery or an input for receiving mains power. Optionally, the hair care appliance further includes a controller configured to adjust a power supplied to the TEC module in response to receiving a user input, to control the TEC module to vary a temperature of the first side and / or second side based on the user input. For example, the controller may be configured to turn the TEC module on or off in response to the received user input. The user input may include a desired temperature (e.g. hot, warm, cold). In some instances, the user input may also include a desired airflow speed (e.g. on / off, high / medium / low). The hair care appliance may include a user interface (e.g. on the housing) for receiving the user input. For example, the user interface may comprise one or more buttons and / or a touch screen. Optionally, the hair care appliance further includes a heater in thermal communication with the airflow pathway, wherein the controller is configured to adjust a power supplied to the heater to vary a temperature of the heater for heating air (e.g. varying a temperature of air) in the airflow pathway. The hair care appliance can therefore controllably adjust the temperature of air in the airflow pathway, across a range of temperatures (e.g. hot, warm, cold). The heater may be configured in any suitable manner, e.g. as a resistive heater. Optionally, the controller is configured to: activate the TEC module in response to receiving a user input selecting a first temperature to cool air in the airflow pathway; and activate the heater in response to receiving a user input selecting a second temperature to heat air in the airflow pathway, wherein the second temperature is higher than the first temperature. The controller therefore selectively activates the TEC module or heater to help achieve a desired temperature setting. As used herein, the phrase “activate” may refer to an increase in an amount of power supplied e.g. to the TEC module or heater. For example, activating the TEC module may comprise turning on a supply of power to the TEC module or, in the case where the TEC module is already turned on, increasing the supply of power to the TEC module to increase a temperature differential between the first and second sides. Likewise, activating the heater may comprise turning on a supply of power to the heater or, in the case where the heater is already turned on, increasing the supply of power to the heater so that the heater reaches an even higher temperature than the heater’s starting temperature. Optionally, the controller is further configured to deactivate the heater in response to receiving the user input selecting the first temperature. Alternatively or in combination, optionally, the controller is further configured to deactivate the TEC module in response to receiving the user input selecting the second temperature. By deactivating the heater and / or TEC module in this manner, the controller can help to conserve power consumption of the appliance, while providing active heating / cooling when desired. As used herein, the phrase “deactivate” may refer to a reduction in an amount of power supplied e.g. to the TEC module or heater. For example, deactivation of the TEC module may comprise turning off the TEC module, or reducing an amount of power supplied to the TEC module e.g. to such an extent that the TEC module only provides zero or negligible active cooling to air in the airflow pathway. Likewise, deactivation of the heater may comprise turning off a supply of power to the heater, or reducing the amount of power supplied to the heater e.g. to such an extent that the heater has an overall reduction in temperature over time. Optionally, the second side of the TEC module is in thermal communication with the heater for emitting heat to the heater. This allows energy from the TEC module to be used to help increase the temperature of the heater, thereby supporting a quicker increase in temperature when the appliance is switched from the first temperature to the second temperature. Likewise, energy from the heater can be applied to the TEC module to induce a thermal gradient in the TEC module. Optionally, the airflow pathway comprises a first branch and a second branch; wherein the heater is in stronger thermal communication with the second branch than the first branch for heating air in the second branch; wherein the airflow assembly further comprises a diversion mechanism configured to transition between a first configuration in which the diversion mechanism directs air along the first branch and a second configuration in which the diversion mechanism directs air along the second branch; and wherein the controller is further configured to: transition the diversion mechanism to the first configuration in response to receiving the user input selecting the first temperature; and transition the diversion mechanism to the second configuration in response to receiving the user input selecting the second temperature. This arrangement helps to support a quick transition between the first and second temperatures. Because the heater is in stronger thermal communication with the second branch than the first branch, the second branch can be heated more quickly and can retain a higher temperature than the first branch. Conversely, by diverting the air along the first branch (away from thermal communication with the heater) in response to the first temperature, the effect of the heater’s thermal mass on air temperature can be reduced, thereby enabling airflow to be cooled more quickly and to a greater extent in response to the first temperature selection. As used herein, the “second branch” may also be referred to as a “hot” branch, whereas the “first branch” may be referred to as a “cold” branch. Similarly to the “cold” and “hot” sides of the TEC module, these terms are intended as labels to refer to the relative temperatures of the branches in use. It will be appreciated that, when the appliance is turned off, the two branches may be in thermal equilibrium. Optionally, the heater may provide negligible or no heating to air in the first branch. Optionally, the heater may be thermally isolated (thermally independent) from the first branch, to inhibit heat transfer from the heater to air in the first branch. For example, the appliance may comprise a thermal insulator or thermal shield to inhibit heat transfer between the heater and the first branch. The diversion mechanism may be configured in any suitable manner to alternate airflow between the first and second branches. For example, the diversion mechanism may comprise a valve assembly (having one or more valves) or an assembly of one or more movable walls (or ducts or barriers or physical structures), which are switchable to divert airflow between the first and second branches. Optionally, the airflow pathway further comprises a joint segment upstream of the first branch and second branch, the joint segment comprising the diversion mechanism. As used herein, a “joint segment” may refer to a portion of the airflow pathway that terminates in a junction or a point at which the airflow pathway branches into two or more portions (which may be referred to as “branched portions”). The diversion mechanism may comprise one or more switching valves, one or more moveable flaps, or one or more deflectors for changing the direction of flow of the airflow from one branch to another (and vice versa). Optionally, the first side of the TEC module is in thermal communication with the joint segment of the airflow pathway for absorbing heat from air in the joint segment. Accordingly, the TEC module can be located upstream of the diversion mechanism. The TEC module can therefore be used to affect temperatures on either branch, by virtue of the TEC module’s thermal communication with the joint segment of the airflow pathway. This can also provide further benefits in combination with a phase change module (discussed below). The first side of the TEC module may be in stronger thermal communication with the joint segment than the first and / or second branches. Optionally, the first side of the TEC module may be thermally isolated from the first and / or second branches (e.g. using thermal insulation / a thermal shield), so as to provide only minimal cooling to the first and / or second branches. Optionally, the first side of the TEC module is in stronger thermal communication with the first branch than the second branch for absorbing heat from air in the first branch. The TEC module can therefore selectively cool down the airflow in the first branch (to a greater extent than the second branch) to help provide a quick and effective reduction in temperature when the first temperature is selected. The TEC module (or the first side thereof) may be located downstream of the diversion mechanism. Optionally, the first side of the TEC module may be thermally isolated from the second branch of the airflow pathway (e.g. using thermal insulation / a thermal shield). This may help to prevent the TEC module from cooling down air in the second branch in use. Optionally, the second side of the TEC module is in stronger thermal communication with the second branch than the first branch for emitting heat into air in the second branch. The TEC module can therefore be used to provide active heating (along the second branch) as well as for providing active cooling when desired (along the first branch or joint segment). Optionally, the appliance further comprises a phase change material, PCM, module in thermal communication with the second side of the TEC module for absorbing heat from the TEC module. When the TEC module is activated, the PCM module can help to draw heat away, thereby improving the cooling effect. Conversely, when the TEC module is deactivated, the PCM module can help release heat and thereby increase the temperature of air. The PCM can therefore be particularly beneficial when the TEC module is in thermal communication with a portion of the airflow pathway that is used both in response to the first temperature setting and the second temperature setting (e.g. a “joint segment” of the airflow pathway, if in a branched configuration). As used herein, the phrase “phase change material” or “PCM” takes its usual meaning to refer to a substance which releases / absorbs sufficient energy at phase transition to provide useful heating or cooling. For example, the PCM may be configured to change phase between liquid and solid to thereby store and release heat. According to another aspect, there is provided a hair care appliance that incorporates a branched airflow pathway without requiring a TEC module. Accordingly, there is provided a hair care appliance comprising: an airflow assembly comprising an airflow generator and an airflow pathway, the airflow generator being configured to direct air along the airflow pathway towards a user in use; a heater in thermal communication with the airflow pathway; a controller configured to adjust a power supplied to the heater to vary a temperature of the heater for heating air in the airflow pathway; wherein the airflow pathway comprises a first branch and a second branch; wherein the heater is in stronger thermal communication with the second branch than the first branch for heating air in the second branch; wherein the airflow assembly further comprises a diversion mechanism configured to transition between a first configuration in which the diversion mechanism directs air along the first branch and a second configuration in which the diversion mechanism directs air along the second branch; wherein the controller is configured to: transition the diversion mechanism to the first configuration in response to receiving a user input selecting a first temperature; and transition the diversion mechanism to the second configuration in response to receiving a user input selecting a second temperature; wherein the second temperature is higher than the first temperature. By diverting airflow using the branched portions, the air can be more quickly heated / cooled, by mitigating the impact that the heater’s thermal mass has on air temperature in the first (low) temperature setting. The invention includes the combination of the aspects and features described except where such a combination is clearly impermissible or expressly avoided. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 shows a side view of a hair care appliance having a TEC module, PCM module, and a heater in thermal communication with a non-branched airflow pathway. Figures 2A-2D are schematic drawings depicting the temperatures of the TEC module, PCM module, heater, and airflow during operation of the hair care appliance of Figure 1. Figure 3 shows a side view of a hair care appliance having a branched airflow pathway, in which a diversion mechanism is in a second configuration to direct air along a second branch that is in closer thermal communication with a heater. Figure 4 shows a side view of the hair care appliance of Figure 3, with the diversion mechanism transitioned to the first configuration to direct air along a first branch that is thermally isolated from the heater. Figures 5A-5D are schematic drawings depicting the temperatures of the TEC module, PCM module, heater, and airflow during operation of the hair care appliance of Figures 3 and 4. Figure 6 shows a side view of a hair care appliance having a branched airflow pathway, in which the first side of the TEC module is in thermal communication with the first branch, and the second side of the TEC module is in thermal communication with the heater, and showing the diversion mechanism in the second configuration. Figure 7 shows a side view of the hair care appliance of Figure 6, with the diversion mechanism in the first configuration to direct air along the first branch which is in thermal communication with the first side of the TEC module. Figures 8A-8B are schematic drawings depicting the temperatures of the TEC module, heater, and airflow during operation of the hair care appliance of Figures 6 and 7. Figure 9 is a graph depicting a change in temperature over time for different hair care appliances. DETAILED DESCRIPTION Figure 1 shows a hair care appliance 100 according to a first example. The hair care appliance has a housing comprising a handle 102 and a body 104. The body 104 is generally annular surrounding a cylindrical through bore 105. An inlet 106 is provided in the handle 102 at a distal end from the body 104. An outlet 108 is provided in the body 104 at a distal end from the handle 102. In this example, the hair care appliance 100 is embodied as a hair dryer. The appliance 100 includes an airflow assembly comprising an airflow pathway that extends through the housing of the appliance, from the inlet 106 to the outlet 108. In this example, the airflow pathway is generally circular within the handle 102 but becomes annular within the body 104. The airflow assembly further comprises an airflow generator 110, which in this example comprises a fan and motor. The airflow generator 110 is provided in the handle 102, between the body 104 and the inlet 106. The handle 102 is in fluid communication with the body 104. The handle 102 has an internal passage that extends from the inlet to 106 to the body 104. The airflow generator 110 is located in the internal passage. The appliance 100 further includes a thermoelectric cooler (TEC) module 112 that has a first side 114 for absorbing heat and a second side 116 for emitting heat. The second side 116 of the TEC module is in thermal communication with a phase change material (PCM) module 118. In this example, the TEC module 112 and PCM modules 118 are both in the body 104 of the hair care appliance 100 and have an annular shape. In variant examples, the TEC module 112 may be configured differently, e.g. located in another portion of the hair care appliance in thermal communication with the airflow pathway (e.g. within the handle 102) and / or having a different shape (e.g. planar). The hair care appliance 100 further includes a heater 120 which, in this example, is located downstream of the TEC module 112 (between the TEC module 112 and the outlet 108). A controller 122 is configured to adjust a power supplied to the heater 120 in use to vary a temperature of the heater 120 for heating air in the airflow pathway. The controller 122 is also configured to adjust a power supplied to the TEC module 112, to control the TEC module to vary a temperature of the first side 114 and / or second side 116. The appliance 100 may have a user interface (not shown) for receiving a user input that selects a desired temperature (e.g. first or second temperature) to be relayed to the controller 122, which adjusts the power supplied to the TEC module 112 and / or heater 120 accordingly. In use, fluid (denoted by arrows in the drawing) is drawn into the inlet 106 by the action of the airflow generator 110 and flows within the airflow pathway along the handle 102 into the body 104, past the first side 114 of the TEC module 112, through the heater 120, and out the fluid outlet 108. Figures 2A to 2D show schematic diagrams of the temperatures of the heater 120, TEC module 112, PCM module 118 during operation, as well as the resulting temperatures on air (denoted by arrows) flowing through the airflow pathway 124. The schematic temperature diagrams throughout this application are colour-coded using darker shading to correspond to higher temperatures, and lighter / white shading to correspond to lower temperatures. Figure 2A shows the relative temperatures when the appliance 100 is operating normally (at steady state) according to a second (hot) temperature setting. Under this setting, the TEC module 112 is deactivated and therefore has no cooling effect on the air in the airflow pathway 124. Conversely, the heater 120 is activated and hot, so heats up air in the airflow pathway 124 as the air passes the heater 120. If the temperature setting is then changed to the first (cooler) temperature, the controller 122 (shown in Figure 1) will activate the TEC module 112, by increasing a power supplied to a semiconductor layer 115 of the TEC module 112 between the first side 114 and second side 116. This causes the temperature distribution to change, as shown in Figure 2B, so that the first side 114 of the TEC module 112 decreases in temperature and the second side 116 of the TEC module 112 increases in temperature. As this occurs, the PCM module 118 begins to heat up, storing energy from the second side 116 of the TEC module within the PCM. At the same time, the controller also deactivates the heater 120 upon selection of the first temperature setting, and thus the heater 120 starts to cool down. As shown in Figure 2C, after some time operating in the first temperature setting, the PCM module 118 will become fully saturated, reaching a maximum temperature. Likewise, the first side 114 of the TEC module 112 will reach a minimum available temperature, which may be lower than room temperature. The heater 120 can completely cool, e.g. to room temperature. This arrangement therefore provides cold air through the airflow pathway 124. As shown in Figure 2D, when a user returns to the second (hot) temperature setting, TEC module 112 is deactivated such that the PCM module 118 can freely feed the PCM module’s stored energy back through the TEC module 112 and into the airflow pathway 124, effectively pre-heating the air before the air even reaches the heater 120. Meanwhile, the heater 120, which is re-activated and therefore increasing in temperature, further heats the air for delivery to a user. Because the air has been pre-heated due to the PCM module 118, less power is required to re-heat the air, as the energy is effectively recycled from the cooling step. Figures 3 and 4 show different configurations of a hair care appliance 200 according to a second example. The hair care appliance 200 of the second example has similar features to those of the first example except where discussed otherwise below. In this example, the airflow pathway 224 comprises a first branch 226 and a second branch 228. The heater 220 is in stronger thermal communication with the second branch 228 than the first branch 226, for heating air in the second branch 228. The airflow assembly also comprises a diversion mechanism 234 configured to transition between a first configuration (shown in Figure 4) in which the diversion mechanism 234 directs air along the first branch 226 and a second configuration (shown in Figure 3) in which the diversion mechanism 234 directs air along the second branch 226. The controller 222 is configured to transition the diversion mechanism 234 to the first configuration in response to receiving a user input selecting a first (lower) temperature, and to transition the diversion mechanism 234 to the second configuration in response to receiving a user input selecting a second (higher) temperature. The airflow pathway 224 further comprises a joint segment 232 upstream of the first branch 226 and second branch 228. The joint segment 232 comprises the diversion mechanism 234 at an end thereof. The first side 214 of the TEC module 212 is in thermal communication with the joint segment 232 of the airflow pathway 124 for absorbing heat from air in the joint segment 232 in use. In this example, the airflow pathway 224 also comprises a further joint segment 236 downstream of the first branch 226 and second branch 228, the further joint segment 236 comprising the outlet 108 and an outlet diversion mechanism 238. The outlet diversion mechanism 238 is similar to the diversion mechanism 234 of the joint segment 232, and helps to prevent backflow through the second branch 228 when in the first configuration (Figure 4), or through the first branch 226 when in the second configuration (Figure 3), under control of the controller 222. It will be appreciated that in variant examples, the airflow pathway may not include a further (downstream) joint segment, e.g. the second branch and first branch may have separate outlets. Alternatively, in some examples, the airflow pathway may include the further (downstream) joint segment but may not include the outlet diversion mechanism 238 for preventing backflow. Figures 5A to 5D show the relative temperatures in the arrangement of Figures 3 of 4 during use. Figure 5A shows an initial phase when a second (hot) temperature setting is in operation. The heater 220 is activated and hot, and the TEC module 212 is deactivated and with the first and second sides 214, 216 in thermal equilibrium (e.g. at room temperature). The PCM 218 is likewise at room temperature. Airflow travels from the joint segment 232, to the second branch 228 for heating by the heater 220, and through the further (downstream) joint segment 236 that has the outlet. As shown in Figure 5B, when a first (cooler) temperature setting is received, airflow is diverted between the joint segments 232 and 236 to flow through the first branch 226 rather than the second branch 228. At the same time, the heater 220 is deactivated and therefore begins to cool down. The TEC 212 is activated and therefore the first side 214 begins to cool down, in turn reducing the temperature of the air in the joint segment 232. Since the airflow in the first branch 226 circumvents the heater 220 (e.g. is thermally insulated from the heater 220), air is not re-heated as the air passes the heater 220. The air therefore is cooled down relatively quickly. As shown in Figure 5C, as operation continues in the first temperature setting, the first side 214 of the TEC module 212 reaches a maximum cold setting (e.g. lower than room temperature), and the PCM module 218 reaches a maximum (saturated) heat storage. The heater 220 cools down e.g. to room temperature. As shown in Figure 5D, when the appliance is returned to the second (hot) temperature setting, heat is released from the hot PCM module 218, through the (de-activated) TEC module 212, to pre-heat air in the joint segment 232 of the airflow pathway 224. The diversion mechanisms 234 and 238 are returned to the second configuration (as shown in Figure 3), thereby allowing the preheated air to travel through the second branch 228 past the heater 220, which is re-activated and therefore hot. Because the PCM module is feeding energy back into the airflow, a reduced amount of power is required to change the temperature. Figures 6 and 7 show a hair care appliance 300 according to a third example. Figures 8A and 8B show schematic diagrams of the operation of the hair care appliance 300 of Figures 6 and 7 in use. The hair care appliance 300 of the third example has similar features to the first and second examples except where discussed otherwise. As shown in Figures 6 and 7, the hair care appliance 300 has an airflow pathway 324 comprising a first branch 326 and a second branch 328. Again, the heater 320 is in stronger thermal communication with the second branch 328 than the first branch 326, for heating air in the second branch 328. In contrast to the second example, in the third example, the heater 320 is also in thermal communication with the second side 316 of the TEC module 312. The second side 316 of the TEC module is in thermal communication with the second branch 328 for emitting heat into air in the second branch in use. In this example, the hair care appliance 300 does not include a PCM module 118 or 218 for absorbing heat from the TEC module 312. Instead, heat from the TEC module 312 can be fed into the heater 320 in use, and vice versa. In contrast to the first and second examples, the first side 314 of the TEC module is in thermal communication with the first branch 326 for absorbing heat from air in the first branch 326 in use, rather than being in thermal communication with a joint segment of the airflow pathway. Figure 8A shows the relative temperatures of the TEC module 312 and heater 320 of the third example when the appliance 300 is operating normally according to the second (hot) temperature setting. Under this temperature setting, the TEC module 312 and heater 320 are both activated. The second side 316 is hot and the first side 314 is cold (e.g. at or near freezing temperature). Air flowing along the joint segment 332 is unheated and then increases in temperature as the air passes through the second branch 328 in thermal communication with the second side 316 and the heater 320. When the temperature setting is changed to the first (cooler) temperature, the controller 322 (shown in Figures 6 and 7) deactivates the heater 320, which begins to cool down (as shown by shading in Figure 8B). The controller 322 also transitions the diversion mechanism 334 and the outlet diversion mechanism 338 from the second configuration (shown in Figure 6) to the first configuration (shown in Figure 7), causing the airflow assembly to direct air from the joint segment 332 along the first branch 326 rather than the second branch 328. The TEC module 312 may remain activated. Air flowing from the joint segment 332 through the first branch 326 is then cooled as the air is brough into thermal communication with the first side 314 of the TEC module 312. When the temperature setting is returned to the second (hot) temperature (i.e. the configuration of Figures 6 and 8A), the second side 316 of the TEC module 312 helps to boost the rate at which air flowing through the second branch 328 can be heated. Because the air is diverted around the heater 320 along the first branch 326, the thermal mass of the heater 320 does not limit the rate of cooling in the first temperature setting. Indeed, the thermal mass of the heater 320 keeping the heater warm or hot during the first temperature setting can allow a quicker return to hot airflow when changed to the second temperature setting. In some examples, the heater 320 can remain on even while in the first temperature setting, to provide an even quicker return to hot airflow when returning to the second temperature setting. In this arrangement, some power from the heater 320 can be used to power the TEC module 312, which can enable an even larger temperature differential to be obtained between the first and second sides 314 and 316 of the TEC module 312. Figure 9 shows a graph of the temperature over time for different hair care appliances, when starting from a styling temperature Ts and after switching to a cool setting at time tc. For reference, room temperature is depicted along the y-axis as Tr. The graph shows a series of curves 140A-E corresponding to different appliances. A first curve 140A corresponds to a known hair dryer having a resistive heater. In this arrangement, cooling is achieved by turning off the heater and allowing unheated air to travel over the heater. As can be seen from Figure 9, this results in relatively slow cooling, as a result of the thermal mass of the heater continuing to heat airflow even after the cool air setting is selected. Additionally, it is difficult to obtain temperatures below room temperature Tr because the motor of the air generator continually outputs power (and thus heat) during operation. A second curve 140B corresponds to an example which further implements a TEC module, e.g. according to the first example. The TEC module allows a greater reduction in temperature, to below room temperature Tr. A third curve 140C corresponds to an example which implements a TEC module as well as a branched airflow passageway for circumventing the heater, e.g. according to the second example. The circumvented airflow allows a quicker reduction in temperature compared to the first and second curves 140A-B which have only a single airflow pathway, although there is still a slight delay while the TEC powers on. A fourth curve MOD corresponds to an example which does not implement a TEC module, but which does include a circumvented (branched) passageway, e.g. similar to the second example but without the TEC module 212 or PCM module 218. This provides a quick reduction in temperature, but does not reach the very cold temperatures that are possible with a TEC module. A fifth curve MOE corresponds to an example having a TEC module that can be used both for heating and cooling using a branched passageway, e.g. according to the third example. Because the TEC module 312 always remains on, and has its first side 314 in thermal communication with the first branch 326 and its second side 316 in thermal communication with the second branch 328, no delay is caused from the TEC module powering on or off when switching between the temperature settings. This allows an extremely rapid change in temperature, as well as allowing very low temperatures to be reached.

Claims

1. A hair care appliance comprising:an airflow assembly comprising an airflow generator and an airflow pathway, the airflow generator being configured to direct air along the airflow pathway towards a user in use;a thermoelectric cooler, TEC, module having a first side for absorbing heat and a second side for emitting heat, at least the first side of the TEC module being in thermal communication with the airflow pathway for absorbing heat from the air in the airflow pathway to cool the air that is directed towards the user in use.

2. The hair care appliance of claim 1, further including a controller configured to adjust a power supplied to the TEC module in response to receiving a user input, to control the TEC module to vary a temperature of the first side and / or second side based on the user input.

3. The hair care appliance of claim 2, further comprising a heater in thermal communication with the airflow pathway, wherein the controller is configured to adjust a power supplied to the heater to vary a temperature of the heater for heating air in the airflow pathway.

4. The hair care appliance of claim 3, wherein the controller is configured to:activate the TEC module in response to receiving a user input selecting a first temperature to cool air in the airflow pathway; andactivate the heater in response to receiving a user input selecting a second temperature to heat air in the airflow pathway, wherein the second temperature is higher than the first temperature.

5. The hair care appliance of claim 4, wherein the controller is further configured to deactivate the heater in response to receiving the user input selecting the first temperature.

6. The hair care appliance of claim 4 or 5, wherein the controller is further configured to deactivate the TEC module in response to receiving the user input selecting the second temperature.

7. The hair care appliance of claim 4 or 5, wherein the second side of the TEC module is in thermal communication with the heater for emitting heat to the heater.

8. The hair care appliance of any one of claims 3 to 7, wherein the airflow pathway comprises a first branch and a second branch;wherein the heater is in stronger thermal communication with the second branch than the first branch for heating air in the second branch;wherein the airflow assembly further comprises a diversion mechanism configured to transition between a first configuration in which the diversion mechanism directs air along the first branch and a second configuration in which the diversion mechanism directs air along the second branch; andwherein the controller is further configured to:transition the diversion mechanism to the first configuration in response to receiving the user input selecting the first temperature; andtransition the diversion mechanism to the second configuration in response to receiving the user input selecting the second temperature.

9. The hair care appliance of claim 8, wherein the airflow pathway further comprises a joint segment upstream of the first branch and second branch, the joint segment comprising the diversion mechanism.

10. The hair care appliance of claim 9, wherein the first side of the TEC module is in thermal communication with the joint segment of the airflow pathway for absorbing heat from air in the joint segment.

11. The hair care appliance of claim 8 or 9, wherein the first side of the TEC module is in stronger thermal communication with the first branch than the second branch for absorbing heat from air in the first branch.

12. The hair care appliance of any one of claims 8 to 11, wherein the second side of the TEC module is in stronger thermal communication with the second branch than the first branch for emitting heat into air in the second branch.

13. The hair care appliance of any preceding claim, further comprising a phase change material, PCM, module in thermal communication with the second side of the TEC module for absorbing heat from the TEC module.

14. A hair care appliance comprising:an airflow assembly comprising an airflow generator and an airflow pathway, the airflow generator being configured to direct air along the airflow pathway towards a user in use;a heater in thermal communication with the airflow pathway;a controller configured to adjust a power supplied to the heater to vary a temperature of the heater for heating air in the airflow pathway;wherein the airflow pathway comprises a first branch and a second branch;wherein the heater is in stronger thermal communication with the second branch than the first branch for heating air in the second branch;wherein the airflow assembly further comprises a diversion mechanism configured to transition between a first configuration in which the diversion mechanism directs air along the first branch and a second configuration in which the diversion mechanism directs air along the second branch;wherein the controller is configured to:transition the diversion mechanism to the first configuration in response to receiving a user input selecting a first temperature; andtransition the diversion mechanism to the second configuration in response to receiving a user input selecting a second temperature;wherein the second temperature is higher than the first temperature.Application No: GB2315684.7Examiner: Mark MorgansClaims searched: 1-13Date of search: 11 April 2024Patents Act 1977: Search Report under Section 17Documents considered to be relevant:Category Relevant to claims Identity of document and passage or figure of particular relevance X 1-8& 11- WO 2009 / 074788 A2 13 (HOT STIXX LTD) See figure 19; page 24, line 1 - page 25, line 26 X 1-8& 11- KR 1020210025194 A 13 (KO JUNG CHAN) See figure 7; WPI abstract (accession no. 2021-23928Q); and paragraphs 0043 &0055-0070 X 1-7 &13 KR 101974316 Bl (KANG SU JIN) See figure 1; WPI abstract (accession no. 2019-75383T); and paragraphs 0027-0033, 0048 &0049 X 1-7 &13 JP 2013022251 A (IZUMI PROD CO) See figures 1 &3; WPI abstract (accession no. 2012-E25759); and paragraphs 0019, 0020, 0023 &0028Categories:X Document indicating lack of novelty or inventive step A Document indicating technological background and / or state of the art. Y Document indicating lack of inventive step if P Document published on or after the declared priority date but combined with one or more other documents of same category. before the filing date of this invention. & Member of the same patent family E Patent document published on or after, but with priority date earlier than, the filing date of this application.Field of Search:International Classification:Subclass Subgroup Valid From A45D 0020 / 12 01 / 01 / 2006 A45D 0020 / 10 01 / 01 / 2006 F25B 0021 / 02 01 / 01 / 2006 Hl ON 0010 / 80 01 / 01 / 2023Application No: GB2315684.7Examiner: Mark MorgansClaims searched: 14Date of search: 24 October 2024Patents Act 1977Further Search Report under Section 17Documents considered to be relevant:Category Relevant to claims Identity of document and passage or figure of particular relevance v A 14 US 2021 / 0307478 Al (CONRAD) See figures 9 &10; and paragraphs 0488, 0497, 0498 &0513-0517 X 14 US 6011903 A (NOSENCHUCK) See figures 1-3; column 4, lines 27-37; column 5, lines 44-55; and column 9, lines 32-42 v A 14 WO 2009 / 074788 A2 (HOT STIXX LTD) See figure 19; and page 24, line 1 - page 25, line 26 X 14 KR 20210025194 A (KO JUNG CHAN) See figure 7; and paragraphs 0043, 0044 &0055-0070Categories:v Au Document indicating lack of novelty or inventive step A Document indicating technological background and or state of the art. Y Document indicating lack of inventive step if combined with one or more other documents of same category. P Document published on or after the declared priority date but before the filing date of this invention. & Member of the same patent family E Patent document published on or after, but with priority date earlier than, the filing date of this application.Field of Search:International Classification:Subclass Subgroup Valid From A45D 0020 / 12 01 / 01 / 2006 A45D 0020 / 10 01 / 01 / 2006 F25B 0021 / 02 01 / 01 / 2006Subclass Subgroup Valid From Hl ON 0010 / 80 01 / 01 / 2023

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