EP3384728A1

EP3384728A1 - A heating element for a hairdryer and a method of manufacturing the same

Info

Publication number: EP3384728A1
Application number: EP15804118.6A
Authority: EP
Inventors: Alper YESILCUBUK; Simge TARKUC; Pinar YAVUZ; Oguzhan KAYA
Original assignee: Arcelik AS
Current assignee: Arcelik AS
Priority date: 2015-12-02
Filing date: 2015-12-02
Publication date: 2018-10-10
Also published as: WO2017092800A1

Abstract

The present invention relates to a heating element (1) for a hairdryer comprising: - a body (2) having a plurality of through holes (3) along which an air flow generated by air generating means of an hairdryer is susceptible of passing; - a controlled and tunable resistant film (4) deposited on at least a surface (6) of the body (2) and suitable to get hot when an electric current flows through it thus heating the body (2); and - electrically conductive means (5) arranged on the body (2) in contact with the film (4) and aimed to receive an electrical current from a power supply and to transfer it to the film. The present invention further relates to a method of manufacturing a heating element (1) for a hairdryer.

Description

A HEATING ELEMENT FOR A HAIRDRYER AND A METHOD OF MANUFACTURING THE SAME

The present invention relates to a heating element for a hairdryer and to a method of manufacturing the same.
Hairdryers comprise a body having a case-like shape and comprising a blowing outlet, a motor-driven fan arranged in the body for generating an air flow and a heating element, generally arranged in a blowing portion of the body, through which the air is guided toward the blowing outlet, and aimed to heat the air generated by the fan.
Traditionally the heating element comprises, as a resistant component, a metal wire, generally made of a nickel-chrome alloy, which is a poor conductor of electricity getting easily hot when an electric current flows through it and that does not oxidize when heated, wrapped around a support core, made of an insulating material such as ceramic, fiberglass or plastic.
These known heating elements have however the main disadvantage of emitting UV radiation which damage the molecular structure of the hair. A further disadvantage of the above mentioned heating elements resides on the fact that they do not provide an homogeneous and stable heating. Moreover these heating elements have generally a short life.
In order to overcome these disadvantages, different heating elements have been developed which comprise, as a resistant component, a perforated body generally made of ceramic or glass-ceramic.
Such a heating element is for instance described in the patent application n. EP 2238856 A1 and it comprises a ceramic perforated body having a surface coated with a heat-emitting film and having an upper end surface and a lower end surface coated with a silver paste films for configuring electrodes (electrical conductors aimed to receive an electric current from a power source). When a power supply is provided to the electrodes, the heat-emitting film obtains power so that the heat-emitting ceramic is heated up.
This heating element allows to reach a more homogeneous heating and it is characterized by a longer life compared with the heating elements using wires as resistant components.
However, such heating element requires a longer interval of time and a higher energy consumption to get heated with respect to the heating elements using metal wires as resistant components.
The aim of the present invention is therefore to provide a heating element for a hairdryer which is completely safe to be used, avoiding damages to the hair being dried or styled, and which is time and energy efficient.
A further aim of the present invention is to provide a method of manufacturing such heating element which is easy and accurate to be performed.
These aims have been achieved by the heating element for a hairdryer as defined in claim 1 and by the method of manufacturing such heating element as defined in claim 9. Further achievements have been attained by the subject-matters respectively defined in the dependent claims.
The heating element for a hairdryer realized in order to attain the aim of the present invention is illustrated in the attached figures, where:
Figure 1 – is a perspective view of a heating element for a hairdryer according to the invention.
Figure 2 – is a plan view of the heating element of Figure 1.
Figure 3 – is a cross-sectional view of the heating element of Figure 2 taken from the line A-A.
Figure 4 – is a cross-sectional view of an enlarged portion of the body of the heating element of Figure 2 taken from the line B-B.
Figure 5 – is a perspective view of the cross-section of the heating element of Figure 3.
The elements illustrated in the figures are numbered as follows:

Heating element
Body
Through holes
Film
Electrically conductive means
Surface
Oxide layer
Partitions

The heating element 1 for a hairdryer according to the invention is intended to be arranged inside a case-like shaped body of a hairdryer, in particular in a blowing portion of the body upstream of a blowing outlet, and it is aimed to heat an air flow generated by air generating means, such as a motor-driven fan, also arranged in the body of the hairdryer, before such air flow is emitted through the blowing outlet.
The heating element 1 comprises a body 2, having a plurality of through holes 3 along which the air flow generated by the air generating means of the hairdryer is susceptible of passing. For instance, according to an embodiment illustrated in the attached figures, the body 2 may have a cylindrical hollow shape and being provided with a plurality of partitions 8 intersecting the hollow volume delimited by the cylinder.
The heating element 1 further comprises a film 4, deposited on at least a surface 6 of the body 2 and suitable to get hot when an electric current flows through it thus heating the body 2.
In the embodiment illustrated in the attached pictures, the film 4 could be for instance deposited only on the partitions 8 of the body 2, instead of on the whole surface of the body 2.
The heating element 1 comprises also electrically conductive means 5 arranged on the body 2 in contact with the film 4 and aimed to be connected to a power supply in order to let an electric current flow through the film 4. The film 4 has a controlled and tunable resistivity depending on its composition and thickness which are selected accordingly by the producer.
In particular, the film is selected in order to have an electrical resistivity as higher as possible, while allowing electric current to flow through it.
To this aim, in a preferred embodiment, the electrical resistivity of the film 4 is between 10 Ω/sq and 100 Ω/sq.
In a further preferred embodiment, the thickness of the film 4 is between 1 μm and 100 μm.
According to the present invention, the body 2 is made of aluminium or an aluminium alloy. The fact that the body 2 is made of a metallic material and in particular of an aluminium based metallic material allows it to get quickly heated, thus requiring a minor time and energy consumption compared with heating elements having the body made of a ceramic or glass-ceramic material.
According to an embodiment, at least the surface 6 of the body 2 coated with the film 4 comprises a precoating oxide layer 7. This oxide layer 7 of aluminium oxide is made grown at least on the surface 6 of the body 2 intended to be coated with the film 4 and it has the aim of protecting the substrate material, i.e. the aluminium or aluminium alloy, from the direct contact with the film 4 which may cause adverse chemical reactions.
To this aim an oxide layer 7 having a sufficient thickness to efficiently protect the substrate material is grown on the surface 6 of the body 2. In an embodiment, the thickness of the oxide layer is between 1 µm and 500 µm.
According to an embodiment, the oxide layer 7 can be grown on the whole surface of the body 2, thus rendering the manufacturing process easier to be performed.
In an embodiment, the precoating oxide layer 7 is obtained by means of anodizing. This allows obtain a thick oxide layer 7 on the surface 6 of the body 2.
In an embodiment the film 4 comprises one or more of the following compounds: fluorine doped tin oxide (FTO), indium tin oxide (ITO), graphene, aluminium-doped zinc oxide (AZO) or silver nano wires. These compounds and material, in fact, allow the thin film 4 to reach the desired tunable resistivity property, thus allowing to efficiently convert the electrical energy provided to the film 4 in thermal energy and to hence quickly heat the body 2.
In a further embodiment, the film 4 is obtained by means of a spray deposition technic, such as for instance spray pyrolysis, which allows to obtain a film 4 having high homogeneity and characterized by a high purity of the compounds or material which is made of.
In an alternative embodiment, the film 4 is obtained by means of a vapour deposition technic, such as chemical or physical vapour deposition.
According to an embodiment, the electrically conductive means 5 are defined by busbars attached on the surface of the body 2, as illustrated in the attached figures. The busbars, by creating an extended contact area with the film 4, where an electrical contact between the electrically conductive means 5 and the film 4 occurs, allow to efficiently transmit electrical current to the film 4 and hence to efficiently promote the heating of the film 4 and, as a consequence, of the body 2.
In an embodiment, the busbars are obtained by depositing a metal layer on the body 2. The deposition of the metal layer can be obtained by means of an electroless plating or by means of a vapour deposition technic, such as chemical or physical vapour deposition.
The present invention comprises also a method of manufacturing a heating element 1 for a hairdryer, in particular as above described, for which the same reference numbers will be maintained.
The method according to the invention comprise at first providing a body 2 having a plurality of through holes 3 and made of aluminium or an aluminium alloy and growing an oxide layer 7 on at least a surface 6 of the body 2. This allows to grow on the desired surface 6 of the body 2 or on the whole surface of the body 2 an oxide layer 7 thicker than the oxide layer naturally present on the surface of a body made of aluminium or of an aluminium alloy and in particular having the desired thickness.
The method further comprises depositing a film 4 on the surface 6 of the body 2 where the oxide layer 7 was grown or just on a portion of it and providing electrically conductive means 5 on the body 2, in contact with the film 4.
According to a version of the method, growing the oxide layer 7 on the surface 6 of the body 2 is made by anodizing.
According to this technic, the body 2 is put in contact and preferably immersed in an electrolytic solution and a direct current is passed through an electrolytic solution, with the body 2 serving as the anode. By selecting accordingly the electrolytic solution it is possible to obtain an oxide layer 7 having the desired physical property, such as porosity, and the desired thickness.
In a version of the method, the film 4 is deposited on the surface 6 of the body 2 covered with the oxide layer 7 by means of spray deposition technic, such as for instance spray pyrolysis or ambient spray. Such spray technics have generally the advantage of good applicability in industry since it can be applied on complex shapes easily.
In an alternative version of the method, the high-resistivity film 4 is deposited on the surface 6 of the body 2 covered with the oxide layer 7 by means of a vapour deposition, such as chemical or physical vapour deposition, which beside allowing to obtain high purity and high density film, has the advantage of being more environmental friendly compared with other deposition technics.
Differently the film could be deposited on the surface 6 of the body 2 by means of film-casting technics, such as Doctor Blade or Meyer rod, or by means of dip coating or spin coating.
According to a version of the method, the electrically conductive means 5 are provided on the body 2 by depositing a metal coating, in particular defining busbars on the body 2.
In a further embodiment, the metal coating defining the electrically conductive means 5 is deposited on the body 2 by means of vapour deposition, and in particular by means of chemical or physical vapour deposition.
This has the advantages, compared with other deposition technics, such as for instance the deposition of a strip of electrically conductive paste, to ensure more regular dimensions and in particular thickness of the metal coating, i.e. of the busbar, thus ensuring a more homogeneous transmission of electrical energy to the high-resistivity film 4 and hence a more homogeneous heating of the latter and of the body 2.
In an alternative version of the method according to the invention, the metal coating defining the electrically conductive means 5 is deposited on the body 2 by means of an electroless plating.
The heating element 1 for a hairdryer according to the present invention ensures an efficient and homogeneous heating of the air generated by air generating means of the hairdryer and emitted through the blowing opening of the latter, in a time and energy effective manner, since it can be heated up more quickly and requiring a less energy consumption with respect to the heating element 1 currently available in the state of the art and in particular with respect to the known heating elements comprising a body made of ceramic or glass-ceramic.
Moreover the heating element 1 according to the invention allows to limit the emission of UV radiation, thus preventing damages to the hair being dried or shaped by means of a hairdryer incorporating it.

Claims

A heating element (1) for a hairdryer comprising:

- a body (2) having a plurality of through holes (3) along which an air flow generated by air generating means of an hairdryer is susceptible of passing;

- a film (4) deposited on at least a surface (6) of the body (2) and suitable to get hot when an electric current flows through it thus heating the body (2);

- electrically conductive means (5) arranged on the body (2) in contact with the film (4) and aimed to be connected to a power supply in order to allow an electric current to flow through the film (4);

characterized in that the body (2) is made of aluminium or an aluminium alloy.
A heating element (1) for a hairdryer as in Claim 1, characterized in that at least the surface (6) of the body (2) coated with the film (4) comprises a precoating oxide layer (7).
A heating element (1) for a hairdryer as in Claim 3, characterized in that the precoating oxide layer (7) is obtained by means of anodizing.
A heating element (1) for a hairdryer as in any of the preceding claims, characterized in that the film (4) comprises one or more of the following compounds: fluorine doped tin oxide (FTO), indium tin oxide (ITO), graphene, aluminium-doped zinc oxide (AZO) or silver nano wires.
A heating element (1) for a hairdryer as in any of the preceding claims, characterized in that the film (4) is obtained by means of a spray deposition technic.
A heating element (1) for a hairdryer as in any of the claims 1-4, characterized in that the film (4) is obtained by means of a vapor deposition technic.
A heating element (1) for a hairdryer as in any of the preceding claims, characterized in that the electrically conductive means (5) are defined by busbars attached on the surface of the body (2).
A heating element (1) for a hairdryer as in Claim 6, characterized in that the busbars are obtained by depositing a metal layer on the body (2) by means of a vapor deposition technic or an electroless plating technic.
A method of manufacturing a heating element (1) for a hairdryer comprising:

- providing a body (2) having a plurality of through holes (3) and made of aluminium or an aluminium alloy;

- growing an oxide layer (7) on at least a surface (6) of the body (2);

- depositing a film (4) on the at least a surface (6) of the body (2) covered with the oxide layer (7); and

- providing on the body (2), in contact with the film (4), electrically conductive means (5).
A method of manufacturing a heating element (1) for a hairdryer as in claim 9 wherein the growing of an oxide layer (7) on at least a surface (6) of the body (2) is made by anodizing.
A method of manufacturing a heating element (1) for a hairdryer as in claim 9 or 10, wherein the film (4) is deposited on the at least a surface (6) of the body (2) covered with the oxide layer (7) by means of a spray deposition technic.
A method of manufacturing a heating element (1) for a hairdryer as in claim 9 or 10, wherein the film (4) is deposited on the at least a surface (6) of the body (2) covered with the oxide layer (7) by means of vapour deposition.
A method of manufacturing a heating element (1) for a hairdryer as in any of the claims 9-12, wherein the electrically conductive means (5) are provided on the body (2) by depositing a metal coating.
A method of manufacturing a heating element (1) for a hairdryer as in claim 13 wherein the metal coating defining the electrically conductive means (5) is deposited on the body (2) by means of vapour deposition.
A method of manufacturing a heating element (1) for a hairdryer as in claim 13 wherein the metal coating defining the electrically conductive means (5) is deposited on the body (2) by means of an electroless plating technic.