Vaporization chamber for steam diffusion hairdressing appliance.

Abstract

Vaporization chamber for steam diffusion hairdressing appliance The present invention relates to a vaporization chamber for steam diffusion hairdressing appliance, comprising a hollow body defining a free interior space capable of allowing fluid circulation between at least one inlet for supplying a liquid product to be vaporized and at least one outlet for said at least partially vaporized product, said steam chamber being characterized in that it comprises at least one heating wall intended to be placed in thermal contact with a heating element and made of a plastic material having a thermal conductivity of less than 10 W / mK at 100°C. Figure for abstract: Fig 2

Description

Description Title of the invention: Vaporization chamber for apparatus for steam diffusion hairstyle.

[0001] — The present invention relates to a vaporization chamber, in particular for steam-diffusing hairdressing appliance intended for styling or hairdressing of hair. The device is more particularly a hair brush suitable for diffuse steam on hair.

[0002] — Many types of household hairdressing appliances are known which allow the shaping of hair, in particular by straightening, curling or crimping. We can for example, straightening or curling irons or even hairbrushes hair, These devices may include one or more treatment surfaces heated or heating, The general construction of such devices is well known.

[0003] — In order to improve treatment, some devices have long provided for the dis- steam delivery to the surface to be treated, in particular a lock of hair or the hair in the case of hairdressing appliances.

[0004] — Thus, document US2880299A, for example, describes a curling iron capable of distribute steam onto a lock of hair pinched between two articulated arms and wrapped around said arms. The steam is generated directly from the tank containing liquid water, which also serves as a vaporization chamber. The tank walls are made of the same material as the arms, i.e. in a metallic material which is a good heat conductor. Document EP3097815 sets out implement a similar system, differing in that the tank is remote from the unit of portable treatment in a base housing a vaporization chamber made of stainless steel using an AISI 304 alloy, also a good heat conductor {16.2 W / mK at 100°C).

[0005] — Document US20040000319A 1 describes a device of the hair straightener type also capable of distributing steam on a wick pinched between two equipped arms each of a heating plate. Liquid water contained in a tank is brought by a porous pad in contact with an evaporation plate (32). Walls of the vaporization chamber can be made of PPS (see

[0141] ), however these walls are distinct from the vaporization plate which remains highly conductive of heat.

[0006] Finally, we can also mention brushes and combs, heated or not, capable of distribute steam when used through hair. As a For example, we can refer to documents KR20030085159A and DE19822718A1. Document DE19822718 includes a steam supply duct from the exterior of the comb. Document KR20030085159 vaporizes the water contained in a vaporization chamber formed in a central part of the brush and comprising a heat transfer plate (

[0032] ) produced by an associated heating element (26). Thus, generally speaking, steam is generated by a steam generator consisting essentially of a chamber supplied with liquid water from a separate reservoir and heated to a temperature sufficient to cause its evaporation. Such a vaporization chamber comprises walls generally formed from a heat-conducting material based, for example, on aluminum, magnesium or stainless steel. The steam thus generated is then brought into or near the treatment surface where it is distributed through one or more nozzles. For a precise description of such steam generators, reference may usefully be made to documents US3934597, US3921648, WO2017174035A1., WO2017089582A1, WO2020127851A1 and WO2020127852A 1, among others, which also implement highly heat-conducting vaporization elements. A problem with using such materials is that they have a relatively high density and that making a vaporization chamber from them makes the device significantly heavier. This is particularly important for devices integrating the vaporization chamber, and possibly the reservoir, into a portable treatment unit. Furthermore, such materials are susceptible to fouling by scale. This fouling can lead to obstruction of the liquid water inlet and / or steam outlets. There is therefore a need for a solution making it possible to produce lighter steam chambers and, where appropriate, less sensitive to fouling by scale. To this end, the present application relates to a vaporization chamber comprising a hollow body defining a free interior space capable of allowing fluid circulation between at least one inlet for supplying a liquid product to be vaporized and at least one outlet for said at least partially vaporized product. According to the invention, the vaporization chamber is characterized in that it comprises at least one heating wall intended to be placed in thermal contact with a heating element and made of a plastic material having a thermal conductivity of less than 10 W / mK at 100°C, preferably less than 1 W / mK at 100°C. By contact heating element is meant direct contact or contact via a highly heat-conducting part (thermal conduction greater than 50 W / mK, in particular greater than 150 W / mK, for example a part thin (thickness less than 1mm, better less than 0.5mm) aluminum. By free space is meant a non-full space, in particular not filled with a porous material occupying said interior volume as in document WO2017174035A1. In accordance with the present application, the vaporization chamber has, at a minimum, a free space allowing the liquid water leaving an orifice to be able to come directly into contact with at least one evaporation surface of the heating wall. Preferably, the vaporization chamber is completely free of porous materials. Indeed, it was surprisingly found that it was possible to use a relatively non-conductive material compared to the usual materials mentioned above while retaining good vaporization properties for the liquid water introduced into said chamber. More specifically, the relatively poor thermal conductivity of such a plastic material does not prevent, even if it is slower, a sufficient rise in temperature of the heating wall to allow the evaporation of the liquid water which would penetrate into the chamber, especially since the constituent walls of a vaporization chamber, and in particular the heating wall, remain relatively thin (thickness less than 5 mm, preferably less than 3 mm, in particular of the order of 2 mm) and the flow rate of introduction of liquid water is also relatively low (less than 5 g per minute, preferably less than 3 g per minute, better still less than 1 g per minute). Thus, it is possible to benefit from the advantages of these materials. The use of such materials also makes it possible to consider a reduction in the manufacturing cost of the vaporization chamber. The plastic material used may consist of a single plastic material or a mixture of plastic materials. In the case of a mixture of plastic materials, the characteristics are given for the mixture. Preferably, each constituent material of said mixture meets the given characteristics. Of course, the material used is heat-resistant and has a melting point above 150°C, preferably above 200°C. It has also been found that the use of such materials has advantages in terms of resistance to fouling and scale. Without wishing to be bound by any theory, it is likely that the use of a material with low thermal conductivity induces a slower vaporization rate, which allows for a better distribution of the liquid water in the vaporization chamber. Indeed, the fouling of the vaporization chambers is essentially due to the accumulation of scale substantially at the injection point of the liquid water, the latter being vaporized very quickly in a chamber using a standard highly conductive metallic material. Preferably, the plastic material used has a density at 25°C of less than 2000 kg / m3. The use of such a material makes it possible to significantly reduce the weight of the vaporization chamber. As previously indicated, such a weight saving is particularly significant for devices comprising a portable unit integrating the vaporization chamber. The plastic material used may include fillers, in particular fiber fillers. Preferably, the plastic material used includes less than 10% fillers. According to particular embodiments, the plastic material is chosen from polyimides (PI), polyphenolsulfones (PPSU), polyphenylene sulfides (PPS), polytetrafluoroethylene (PTFE), polyether-ether-ketones (PPEK), polyether-sulfones (PESU), and their mixture, in particular mixtures of these materials with each other. A preferred material is polyphenolsulfones (PPSU) whose thermal conductivity is about 0.35 W / mK at 100°C and whose density is around 1290 kg / m3 at 25°C, which allows a mass reduction of the walls made of this material of about 52%. Advantageously, the vaporization chamber has at least one wall other than the heating wall made of a plastic material also having a thermal conductivity of less than 10 W / mK at 100°C, preferably a material identical to that of the heating wall. It may indeed be interesting to also take advantage of the low thermal conductivity of these materials to produce other walls of the vaporization chamber so as to better insulate any adjacent parts of the device. Thus, as explained previously, the use of such materials for the production of the heating wall (relatively thin and in thermal contact with the heating element) does not substantially impact the evaporation performance of the liquid water admitted into the chamber.However, for the walls located further away from this heating element, they can fully fulfill a thermal insulation role, in particular with respect to an external shell of the device, aimed in particular at forming a gripping part. Advantageously, at least one wall other than the heating wall, preferably a wall opposite the heating wall of the vaporization chamber, is made from a plastic material having a thermal conductivity lower than that of the material used for the heating wall. The walls other than the heating wall may have a thickness of around 2 mm, and in particular close to or identical to the thickness of the heating wall. Obviously, one or more walls other than the heating wall may have a thickness greater than the thickness of the latter depending on the insulation requirements. thermal insulation of elements external to the vaporization chamber, in particular the upper wall usually close to an external shell of a grip handle. Depending on the walls made of a plastic material, all or part of said walls or even the entire vaporization chamber may be made by injection molding. According to a particular embodiment, the heating wall has a concave inner surface, in particular substantially semi-cylindrical. It has in fact been found that such a shape for the surface for receiving liquid water makes it possible to obtain more homogeneous vaporization and water vapor. The present application also relates to a steam generator, in particular for a steam diffusion hairdressing appliance, comprising at least one vaporization chamber according to the invention and at least one electrical heating element in contact with the heating wall of the vaporization chamber. According to a preferred embodiment, the heating element is arranged on an outer surface of the heating wall. Alternatively, the heating element is arranged inside the heating wall. According to another embodiment, the heating element is common to the heating wall of the vaporization chamber and to a treatment surface of the device. For an example of a common heating element, reference may be made to the applicant's application FR21 / 09775, not yet published. The present application also relates to a steam diffusion household appliance comprising at least one steam generator according to the present application and a reservoir capable of containing a quantity of a liquid product to be vaporized, said reservoir being fluidly connected to at least one liquid product supply inlet of the vaporization chamber separate from the reservoir, said vaporization chamber having at least one outlet for the at least partially vaporized product fluidly connected to steam diffusion orifices of a treatment surface of the appliance. In accordance with the present application, the vaporization chamber is a chamber according to the invention. The term household appliances refers to devices and tools using electricity and intended to meet domestic needs. Preferably, the product to be vaporized is water, in particular non-demineralized, non-distilled, and unfiltered water. In particular, the water used has a hardness (hydrotimetric title) greater than 8 °f, preferably greater than 15 °f. Preferably, the water used has a hardness less than or equal to 30 °f. If necessary, the water used may be softened so as to reduce its hardness to between 15 and 30 °f, preferably between 15 and 20 °f. In an advantageously complementary manner, the vaporization chamber is capable of be supplied with liquid product contained in the tank by at least one active pumping member. Preferably, the pumping member is an electrical member, and in particular a positive displacement pump, for example a peristaltic pump or a diaphragm pump. Preferably, the device is a hairdressing device such as a hair straightener or a hair brush. The term "brush" means a hair treatment device comprising a single arm carrying a plurality of teeth between which the hair is received as the brush passes over the hair. The brush may have a single row of teeth, in which case it is otherwise called a comb, or may have a plurality of rows of teeth. The brush may include a heated treatment surface. The teeth may also be actively heated or not. By "hair straightener" is meant a hair treatment device comprising two arms articulated relative to each other around a hinge between an open configuration and a closed configuration. At least one arm, and preferably each arm, is equipped with a treatment surface in the form of a heating plate. During the operations of treating a lock of hair, the latter is introduced between the two arms in the open position, then the two arms are manually closed over the lock of hair. The latter is then subjected, until the two arms open and the lock of hair is extracted, to the heat emitted by the heating element, the device being able to be moved along the lock. Advantageously, the vapor chamber, and preferably the reservoir, are integrated into a portable treatment unit of the device, in particular in a handle thereof. In particular, the reservoir may be integrated into a handle thereof, and the vaporization chamber may preferably be located in the immediate vicinity of a treatment surface of the device so as to minimize the vapor path from the vaporization chamber to the diffusion nozzles. As indicated previously, the resistive heating element is preferably common to the heating wall of the vaporization chamber and to heat the treatment surface. The pumping member may of course also be integrated into the handle. Other aims, characteristics and advantages of the invention will appear on reading the following description, given solely by way of non-limiting example, and made with reference to the appended drawings in which: [Fig.1] is a schematic representation in longitudinal section of a hair brush capable of delivering steam to the hair. [Fig.2] is a schematic longitudinal sectional representation of the treatment portion of the hair brush of [Fig.1] showing the vaporization chamber. [Fig. 1] is a schematic representation in longitudinal section of a brush 100 capillary capable of distributing steam to the hair. Although illustrated by way of example by a hair brush, the present application may also relate to other household appliances distributing water vapor, and in particular other household hair treatment appliances capable of distributing water vapor to the hair. An example of another appliance is a hair straightener as described in particular in document FR2967018A1. The hair brush 100 comprises a gripping handle 110 and a treatment head 120. The head 120 comprises a set of teeth 121 arranged on a support plate 122 in a plurality of rows. The rows of teeth 121 extend substantially along a longitudinal axis of the brush X. In the example shown, the support plate 122 is substantially flat and has a substantially rectangular shape extending in the extension of the gripping handle 122. It is obviously possible to have a curved support plate, the teeth 121 then being preferentially located on a concave surface of the support plate, or even a substantially cylindrical support plate. In a particular embodiment, the support plate 122 and / or the teeth 121 may be heated. Preferably, only the teeth 121, or even only part of the teeth 121, are heated. The head 120 also comprises a plurality of steam outlets 130 emerging from the support plate 122. The steam outlets or nozzles 130 may be located between teeth 121 of one or more rows or be distinct and in particular arranged along an edge of the support plate 122. Alternatively, the steam outlets 130 can be made in the teeth 121, and in particular open onto one side of these. According to the embodiment shown, the steam nozzles 130 open between the teeth 121 of the same row, in this case between the teeth of a middle row, thus forming a row of steam outlets 130 extending substantially in the extension of the handle 110. The steam is conveyed to the steam outlets from a vaporization chamber 350 integrated into the device 100 through one or more diffusion channels passing through the support plate 122, and the teeth 121 if applicable. According to the example shown, the vaporization chamber 350 is integrated into the head 120 at the rear of the support plate 122. Such elements are well known to those skilled in the art. In general, the vaporization chamber 350 comprises a hollow body forming an enclosure and defining a free interior volume, i.e. not occupied by any filling material and in particular devoid of any absorbent element, capable of allowing fluid circulation between at least one inlet for supplying liquid water 353 to be vaporized and at least one outlet for the water under vapor form. The volume of the vaporization chamber is preferably 20 to 100 cm*, better still 30 to 70 cm, for example around 45 cm. The reservoir may have a volume of between | mL and 50 mL. Preferably, the cavity has a height greater than or equal to 0.5 cm or even greater than or equal to 1 cm. Preferably, the cavity has a height less than or equal to 5 cm, or even less than or equal to 2 cm, in particular less than or equal to 1.5 cm. To do this, the vaporization chamber 350, and in particular a part with which the liquid water is intended to come into contact to be vaporized, is capable of being heated to a sufficient temperature, in particular by a resistive heating element 351 in contact with a wall 352 of said chamber. The assembly formed by the vaporization chamber and the resistive heating element forms a steam generator. More particularly, the heating temperature is greater than 180°C. The resistive heating element 351 may be common to the vaporization chamber and to a heating treatment surface 122 of the household appliance if applicable. The heating elements may also be separate, in particular so as to be able to be controlled independently. The part in contact with the heating element 351 and with which the liquid water is intended to come into contact to be vaporized is designated by the term heating wall 352, or lower wall, the latter being generally oriented so that the liquid water admitted into the chamber falls by gravity onto an inner face of said wall during use of the appliance. The vaporization chamber 350 also comprises one or more interior walls forming a set of baffles (not visible) between the liquid water inlet 353 and the water outlet in vapor form. In particular, the baffles are located close to the water outlet in vapor form. Thus, preferably, the vaporization chamber has less than 50%, preferably approximately 25%, of its interior space provided with baffles and more than 50%, preferably approximately 75%, of its interior space without baffles, the supply of liquid water taking place in the area without baffles. The steam outlet is generally in the form of one or more orifices, in particular in the form of a groove or slot provided in an upper wall of the vaporization chamber, said upper wall forming a cover for closing and sealing the vaporization chamber. Here, due to upside-down use of the device, the steam outlet is also provided in the lower wall and is not visible. The steam is then fed to a distribution groove 124 made in the treatment plate 122. The vaporization chamber 350 is supplied with liquid water from a reservoir 300 by a positive displacement pump 200, for example a peristaltic pump or a diaphragm pump, The reservoir 300 is integrated into the device that constitutes the hair brush 100, in particular in its handle 110. It can advantageously be removable so that it can be easily filled. Alternatively, a filling orifice 301 can be provided in a wall of the handle 110. The filling orifice 301 can be equipped with a valve or flap to prevent any leakage of the liquid from the reservoir 300. The pump is also integrated into the handle of the device. Preferably, the device is configured to supply the vaporization chamber 350 with liquid water so as to obtain a vapor diffusion rate greater than or equal to 0.5g.min-1 and less than or equal to 5g.min-1. Preferably, the vapor diffusion rate is less than or equal to 1g.min-1, preferably around 0.8g.min-1. The liquid water inlet 353 is in the form of a pipe or tube passing through a wall and penetrating into the interior of the vaporization chamber so as to open at a non-zero distance from the walls of said chamber. Preferably, the liquid water inlet pipe has a terminal opening (not visible). Alternatively or in a complementary manner, the pipe may have one or more orifices arranged along the latter. Generally speaking, it should be noted that the or each liquid water distribution orifice inside the vaporization chamber 350 opens at a distance from internal surfaces of the body forming said vaporization chamber, these internal surfaces including the peripheral wall surfaces and, where appropriate, the internal baffle surfaces. In particular, each orifice opens at least 1 mm from a wall of the vaporization chamber, in particular relative to a heating bottom wall and an upper opposite wall. Relative to side walls and the internal baffles of the chamber, the distance for each orifice may rather reach at least 10 mm. Preferably, the pipe passes through a side wall of the vaporization chamber extending in width, the pipe extending substantially in a longitudinal direction of the vaporization chamber, in particular inside the zone devoid of baffles. More particularly, this pipe extends over at least half, better over approximately 80% of the distance separating the wall 402 crossed and an opposite wall 404 of the vaporization chamber 400. In accordance with the present application, at least the heating wall 352 of the vaporization chamber 350 in contact with the resistive heating element 351 is made of a plastic material having a thermal conductivity of less than 10 W / mK at 100°C. Preferably, the material has a thermal conductivity of less than 1 W / mK at 100°C. In addition, the material used has a density preferably less than 2000 kg / m3 at 25°C. Examples of materials are given in the table | compared to common highly heat-conducting materials. [Tables 1] [Material Conductivity Reduction | Mass Thermal Reduction (Wm [thermal [volume mass [175 0.00% 2700 0.00% |s1 (70.86% [1810 |32.96% 14 92.00% 7500 -177.78% 6.7 96.17% 4400 -62.96% 5.077 97.10% 3970 3.107 98.22% 2980 0.52 99.70% 1420 ; (0.35 99.80% 1290 [99.83% |1350 |50.00% [99.86% |2200 |18.52% polyphenolsulfones [0.35 (PPSU) Ryton R4 (polyphenylene sulfides |0.3 - PPS) Teflon 0.251 (polytetrafluoroethylene - PTFE) 99.86% [1320 polyether-ether-keton |0.25 99.86% 1320 | 51.11% es (PEEK) polyethersulfones 0.18 99.90% 1580 41.48% (PESU) For example, using PPSU or PTFE for a 2mm thick wall with a 30W heating element set to 180°C, the PPSU will heat up to over 130°C, which is sufficient to evaporate liquid water. The temperature rise will be slower than for aluminum but will better insulate the hulls or reduce the speed of water vaporization. So, by putting such a plastic material in direct contact with the heating element or with an aluminum part which is in direct contact with the heating element, and if the latter will heat up between 180°C and 210°C, the plastic will rise in temperature between 130 and 150°C. Advantageously, all the walls, in particular the peripheral walls, and possibly the internal baffles, are made of such a plastic material. Advantageously, the same plastic material can be used for all the walls. The vaporization chamber can be made in one or more parts, for example, by injection molding, and in particular in a maximum of two parts, namely a base (preferably comprising the heating wall) and a cover. Additionally, depending on the needs, an internal surface of the heating wall can be covered in whole or in part with a hydrophobic layer as described in document WO2020127851, said layer being at least positioned under a liquid water injection point. The presence of the hydrophobic layer under the injection point will prevent the liquid from vaporizing at this precise location, by being pushed further away.

Claims

Claims

1. Vaporization chamber (350), in particular for hairdressing appliance (100) vapor diffusion, comprising a hollow body defining a free interior space capable of allowing fluid circulation between at least one supply inlet (353) of a liquid product to be vaporized and at least one outlet of said at least partially vaporized product, said steam chamber being characterized in that it comprises at at least one heating wall (352) intended to be brought into contact thermal with a heating element (351) and made of a material plastic with a thermal conductivity of less than 10 W / mK at 100°C.

2. Vaporization chamber (350) according to claim 1, characterized in that the plastic material has a density at 25°C in- less than 2000 kg / m3.

3. A vaporization chamber (350) according to any one of the claims- dications | or 2, characterized in that the plastic material is chosen among polyimides polyphenolsulfones, poly- sulfides phenylene, polytetrafluoroethylene, polyether-ether-ketones, polyethersulfones.

4. A vaporization chamber (350) according to any one of the claims- indications 1 to 3, characterized in that at least one wall other than the heating wall (352) is made of a plastic material having a thermal conductivity of less than 10 W / mK at 100°C, preferably, a material identical to that of the heating wall.

5. Vaporization chamber (350) according to claim 4, characterized in that at least one wall other than the heating wall (352), preferably entially a wall opposite the heating wall of the va- porization, is made from a plastic material having a thermal conductivity lower than that of the material used for the heating wall.

6. Steam generator, in particular for hairdressing appliance (100) with vapor diffusion, comprising at least one vaporization chamber (350) according to any one of the preceding claims, and at least one electric heating element (351) in contact with the wall of heating of the vaporization chamber.

7. Steam generator according to claim 6, characterized in that the heating element (351) is disposed on an outer surface of the heating wall (352).

8. Steam generator according to claim 6, characterized in that the heating element is arranged inside the heating wall.

9. Household appliance (100) with steam diffusion comprising at at least one steam generator according to any one of the res- indications 6 to 8 and a reservoir (300) capable of containing a quantity of a liquid product to be vaporized, said reservoir being fluidly connected to the less one supply inlet (353) for liquid product from the chamber vaporization chamber (350) separate from the reservoir, said vaporization chamber rization presenting at least one output of the product at least par- tially vaporized fluidically connected to diffusion orifices of steam (124, 130) from a treatment surface (122) of the apparatus, ca- characterized in that the vaporization chamber is a chamber according to any one of claims | to 5.

10. Household appliance (100) according to claim 9, characterized in that said appliance is a hairdressing appliance such as a hair straightener or a hairbrush.

11. Household appliance (100) according to any one of the claims- indications 9 or 10, characterized in that the steam chamber (350), and preferably the tank (300), are integrated into a portable unit of treatment of the device, in particular in a handle (110) thereof.