Infrared hair dryer

Abstract

An infrared hair dryer comprises a shell having an air inlet and an air outlet, the shell comprising a fan driven by a motor; an infrared radiation source for emitting infrared radiation heat; a rear reflector positioned between the fan and the infrared emitter; a filter positioned at the air outlet of the infrared hair dryer, allowing infrared wavelengths contained between 1.2 μm and 15 μm, preferably between 2 μm and 8 μm to leave the infrared hair dryer, and blocking infrared wavelengths not within this range; wherein the thermal inertia of the infrared source allows the infrared source to achieve a temperature of 1000°C in less than 10 seconds, preferably in less than 5 seconds.

Description

Technical Field

[0001] The present invention relates to an infrared hair dryer using infrared (IR) radiation, in particular of a selected wavelength range, and having an improved, low-inertia infrared emitter. Background Art

[0002] Hair dryers using infrared radiation have been used in the past, but they have not been very successful on the market for a variety of reasons. Hair dryers of this type are equipped with large, bulky infrared lamps, which makes it difficult to operate these devices. In addition, prior art infrared hair dryers often produce excessively high temperatures, i.e., up to 230 degrees, thereby damaging the structure of the hair.

[0003] Document FR 2428991 attempted in 1976 to avoid the drawbacks of these infrared lamp hair dryers by proposing a less bulky infrared hair dryer that emits a specific wavelength in a lower temperature range. This document discloses a hair dryer comprising a fan for blowing an air flow out of the hair dryer at a low speed, an infrared energy source for emitting infrared radiation, an anodized parabolic reflector that modifies the energy of the radiation by reflecting only selected wavelengths, and a transparent infrared radiation filter for further narrowing the emitted infrared radiation to a desired wavelength range. The hair dryer of this document uses infrared radiation in a selected wavelength range to produce a lower temperature, which is about 90° C. when the hair dryer is placed at a distance of 25 cm. The preferred wavelength ranges disclosed in this document are about 2 μm to 3 μm and 6 μm to 8 μm, because water absorbs the main energy of this wavelength. The maximum infrared absorption spectrum of wet hair and the most effective drying occur when these wavelengths are emitted from the hair dryer. An advantage of the present invention is that when the hair is dried, the dry hair protects the scalp because it does not absorb the selected infrared wavelengths.

[0004] However, the downside of the device is that the emitter takes a long time to heat up, at 80 seconds, and the user must wait for the hairdryer to reach its optimal temperature before using it.

[0005] Purpose of the Invention

[0006] The present invention aims to provide an infrared hair dryer which uses infrared (IR) radiation of a narrow range of wavelengths and which has an infrared emitter with low thermal inertia to be able to reach its operating temperature within seconds, thereby achieving precise temperature regulation to optimize drying.

[0007] Another object of the present invention is to provide an infrared hair dryer having an improved airflow adapted to the specific configuration of the infrared hair dryer. Summary of the invention

[0008] The invention discloses an infrared hair dryer, which comprises:

[0009] - a housing having an air inlet and an air outlet, the housing comprising a fan driven by a motor;

[0010] - an infrared radiation source for emitting infrared radiation heat;

[0011] - a rear reflector positioned between the fan and the infrared emitter;

[0012] a filter positioned at the air outlet of the infrared hair dryer, allowing infrared wavelengths comprised between 1.2 μm and 15 μm, preferably between 2 μm and 8 μm, to leave the infrared hair dryer, and blocking infrared wavelengths not within this range;

[0013] The infrared source has a thermal inertia that allows the infrared source to achieve a temperature of 1000° C. in less than 10 seconds, preferably less than 5 seconds.

[0014] According to a preferred embodiment of the present invention, the infrared hair dryer is further defined by one of the following features or by a suitable combination thereof:

[0015] - The infrared radiation source is in the form of a mesh or etched foil;

[0016] - the thickness of the etched foil is comprised between 30 μm and 150 μm, preferably between 50 μm and 120 μm, most preferably around 100 μm;

[0017] - a mesh or etched foil is arranged in a disc-shaped surface;

[0018] - Etching foil is made of FeCrAl gold;

[0019] - the etched foil is maintained in the blower by a holder made of mica which allows electrical insulation;

[0020] - Infrared radiation source with a power range of 5 to 15 W / m 3 between 10W / m 3 Power density;

[0021] - The filter is a silicon window filter;

[0022] - The rear reflector is an anodized parabolic reflector made of aluminum;

[0023] - a side reflector arranged to reflect peripheral radiation emitted by the emitter, said side reflector being in the shape of a ring;

[0024] - The infrared hair dryer includes a deflector for deflecting the air flow along the wall of the housing to the peripheral air flow;

[0025] - The infrared hair dryer further includes an air flow separator having a central channel for separating the air flow into two sub-air flows, namely a central sub-air flow and a peripheral sub-air flow;

[0026] - The infrared hair dryer includes an air outlet grille located at the air outlet for preventing the user from contacting the filter;

[0027] - The fan driven by the motor of the infrared hair dryer is a radial fan. Description of the Drawings

[0028] Figure 1 is a perspective view of an embodiment of a hair dryer according to the present invention.

[0029] Figures 2 to 5 shows a detailed cross-sectional view of the hair dryer according to the present invention, in which the air flow provided by the fan is deflected to the peripheral air flow by the deflector and impinges on the wall of the hair dryer housing.

[0030] Figure 6 shows a detailed view of the etched emitter of the hair dryer according to the present invention.

[0031] Figure 7 and Figure 8 shows another embodiment of the hair dryer according to the present invention, which has a deflector that separates the air flow into a central sub-air flow and a peripheral sub-air flow.

[0032] Reference numerals

[0033] 1 Hair dryer

[0034] 2 Infrared emitter (infrared source)

[0035] 3 Fan motor

[0036] 4 Fan

[0037] 5 Rear reflector

[0038] 6 Filter (silicon window)

[0039] 7 Housing

[0040] 8 Air inlet

[0041] 9 Air outlet

[0042] 10 Air outlet grille

[0043] 11 Deflector

[0044] 12 Central channel

[0045] 13. Mica holder (infrared emitter support)

[0046] 14 Side reflectors

[0047] 15 Air flow separator DETAILED DESCRIPTION

[0048] The present invention relates to Figures 1 to 5 and Figure 7 , Figure 8 The infrared hair dryer 1 is shown.

[0049] The infrared hair dryer comprises a housing 7 having an air inlet 8 and an air outlet 9. The housing comprises a motor 3 which operates a fan 4 which blows air out of the hair dryer through the air outlet 9. An infrared source 2 is located between the fan 4 and the air outlet 9 for emitting infrared radiant heat. As explained in more detail below, in order to operate, the infrared hair dryer comprises a rear reflector 5 disposed between the fan 4 and the infrared source 2 and a filter 6 at the air outlet 9 of the hair dryer to obtain the emitted infrared wavelengths of about 1.2 μm to about 15 μm, preferably about 2 μm to 8 μm. The airflow provided by the fan is diverted by a diverter 11 to avoid cooling of the infrared emitter and to maintain the infrared emitter at an operating temperature while removing excess heat from the hair dryer body.

[0050] The infrared source 2 has a low thermal inertia, which allows temperatures up to 1000° C. to be achieved in less than 10 seconds, preferably in less than 6 seconds, less than 5 seconds, less than 4 seconds, and most preferably in less than 3 seconds. The thermal inertia of a material represents the resistance of the material to temperature changes when the thermal equilibrium of the material is disturbed. If the disturbance brings the material to a new equilibrium temperature, the thermal inertia is the time required to reach this new equilibrium point. The infrared emitter has a power comprised between 5 and 15 W / m 3 Between 8 and 12 W / m 3 For example, 10W / m 3 The low thermal inertia of the infrared emitter allows the infrared hair dryer to operate within seconds.

[0051] The Stefan-Boltzmann law describes the relationship between the radiant power from a black body and the temperature of the black body, and states that the total energy j* (also called the black body radiance) of all wavelengths radiated per unit surface area of ​​the black body per unit time is proportional to the fourth power of the thermodynamic temperature T of the black body:

[0052] J*=σ·S·T 4

[0053] (σ is the Stepan-Boltzmann constant, equal to 5670373x 10 -8 W·m-2 ·K -4 , S is the radiation coefficient relative to a black body).

[0054] Therefore, the total energy depends on the surface area (to the first power) and the temperature (to the fourth power) of the infrared source. In order to obtain the maximum total energy output, the area of ​​the emitter must be maximized.

[0055] The infrared emitter 2 may be a mesh or etched foil arranged on a disk-shaped surface, such as Figure 6 The purpose is to maximize the emission area within the disk surface. The surface area of ​​the disk is greater than 30cm 2 , preferably greater than 50cm 2 .

[0056] The mesh has the property that for the same heating surface, the mass of the mesh is smaller than that of the wire. Therefore, the mesh heats up faster.

[0057] A preferred alternative to the mesh is an etched foil, such as Figure 6 As shown. A pattern is etched from a metal foil, preferably made of a FeCrAl alloy and having a thickness comprised between 30 μm and 150 μm, preferably between 40 μm and 150 μm, for example a thickness of 100 μm. The etching technique allows making specific geometries that create concentrated locations where heating occurs in the foil. In fact, in the thinner parts of the etched foil, the thermal resistance increases, thereby increasing the heating of these parts of the foil. The thermal inertia of the foil can be reduced by making an optimized design while avoiding overheating of the fragile parts of the foil. As Figure 6 As shown, the elements at the edges or turns are fuller than the rest of the foil. There is no thermal resistance pattern at the corners and legs of the foil and therefore no heating in undesired areas. The etched foil is maintained in the blower by a holder 13 made of a material resistant to high temperatures, for example mica, which allows electrical insulation.

[0058] A rear reflector 5 is disposed between the fan 4 and the infrared emitter 2 to maximize infrared radiation of a desired wavelength in the forward direction and to minimize radiation in the visible spectrum. The reflector is preferably an anodized parabolic reflector made of aluminum with a dark anodized coating on its reflective surface. In use, the infrared emitter 2 heats up and emits infrared radiation. The wavelength of the infrared radiation from the infrared emitter 2 reflected by the parabolic reflector 5 is primarily in the range of about 0.8 μm and above, and substantially all of the remaining visible radiation and infrared radiation is absorbed. A side reflector 14 is also provided to reflect peripheral radiation emitted by the emitter. The side reflector may have a ring-shaped shape and is preferably made of aluminum.

[0059] The hair dryer also includes a filter 6 to further narrow the wavelength and remove unpreferred radiation. The filter is preferably a silicon window filter, located at the air outlet 9. Preferably, the filter filters out most of the infrared radiation from the hair dryer, except for infrared wavelengths greater than about 1.2 μm. The filter can be selected to allow only infrared wavelengths of about 1.2 μm to about 15 μm, or preferably about 2 μm to about 8 μm, to be emitted, depending on the specific filter used. In order to obtain these results, the silicon resistivity must be between 0.25 μΩcm and 25 μΩcm.

[0060] In a preferred embodiment of the present invention, the hair dryer comprises a diverter 11, which is located in the housing to direct the flow. Figures 2 to 5 As shown, the diverter 11 has an elliptical shape to deflect the airflow provided by the fan to the peripheral airflow so as to hit the wall of the housing. The airflow is blown out of the hair dryer from the periphery without passing through the emitter, thereby keeping it at operating temperature. When the airflow provided by the fan is diverted by the diverter 11 to hit the housing wall, the aluminum parts of the hair dryer are cooled to avoid overheating.

[0061] In the second embodiment, the hair dryer further comprises an airflow separator 15 having a central channel 12 for separating the airflow into two sub-airflows, namely a central sub-airflow and a peripheral sub-airflow. Figure 7 and Figure 8 As shown, the central sub-flow passes through the flow separator 15 through the central channel 12, while the peripheral sub-flow hits the walls of the housing and the diverter.

[0062] An air outlet grille 10 is provided at the air outlet 9 to prevent the user from contacting the filter 6 at about 400° C. Therefore, the grille must be made of a thin material that is as transparent as possible to prevent the energy transfer of the hair dryer and to keep the temperature as low as possible.

[0063] The hair dryer of the invention has the following advantages: due to the combined use of infrared radiation of a selected wavelength and the low thermal inertia of the emitter, it is possible to dry the hair efficiently and relatively quickly at low temperatures. During the drying process, the hair temperature reaches 30-60° C. instead of 60-105° C. for conventional hair dryers. In addition, the short heating time of the emitter avoids waiting before the user uses the hair dryer at the optimal temperature for the hair dryer and allows a more precise adjustment of the temperature.

Claims

1. An infrared hair dryer (1), include: - a housing (7) having an air inlet (8) and an air outlet (9), the housing (7) comprising a fan (4) driven by a motor; - an infrared radiation source (2) for emitting infrared radiation heat; - a rear reflector positioned between the fan (4) and the infrared radiation source (2); a filter (6) positioned at the air outlet (9) of the infrared hair dryer, allowing infrared wavelengths between 1.2 μm and 15 μm to leave the infrared hair dryer and blocking infrared wavelengths outside this range; The thermal inertia of the infrared radiation source (2) allows the infrared radiation source (2) to achieve a temperature of 1000° C. in less than 10 seconds; The infrared radiation source (2) is a mesh or an etched foil arranged in a disk-shaped surface.

2. The infrared hair dryer according to claim 1, It is characterized in that The thickness of the etched foil is between 30 μm and 150 μm.

3. An infrared hair dryer according to any one of claims 1 to 2, It is characterized in that The surface area of ​​the disk-shaped surface is greater than 30 cm 2 .

4. An infrared hair dryer according to any one of claims 1 to 2, It is characterized in that The etching foil is made of FeCrAl alloy.

5. An infrared hair dryer according to any one of claims 1 to 2, It is characterized in that The etching foil is maintained in the hair dryer (1) by a holder (13) made of mica which allows electrical insulation.

6. An infrared hair dryer according to any one of claims 1 to 2, It is characterized in that The infrared radiation source has a power of 5 to 15 W / m 3 The power density between .

7. An infrared hair dryer according to any one of claims 1 to 2, It is characterized in that The filter (6) is a silicon window filter.

8. An infrared hair dryer according to any one of claims 1 to 2, It is characterized in that The rear reflector (5) is an anodized parabolic reflector made of aluminum.

9. An infrared hair dryer according to any one of claims 1 to 2, It is characterized in that A side reflector (14) is provided to reflect peripheral radiation emitted by the infrared radiation source, and the side reflector (14) is in a ring shape.

10. An infrared hair dryer according to any one of claims 1 to 2, It is characterized in that The infrared hair dryer comprises a deflector (11) for deflecting the airflow along the wall of the housing (7) to a peripheral airflow.

11. The infrared hair dryer according to claim 10, It is characterized in that The infrared hair dryer further comprises an airflow separator (15), which has a central channel (12) for separating the airflow into two sub-airflows, namely a central sub-airflow and a peripheral sub-airflow.

12. An infrared hair dryer according to any one of claims 1 to 2, It is characterized in that The infrared hair dryer comprises an air outlet grille (10) located at the air outlet (9) to prevent a user from contacting the filter (6).

13. An infrared hair dryer according to any one of claims 1 to 2, It is characterized in that The fan (4) driven by the motor is radial.

14. The infrared hair dryer according to claim 1, It is characterized in that The filter is positioned at the air outlet (9) of the infrared hair dryer, allowing infrared wavelengths between 2 μm and 8 μm to leave the infrared hair dryer and blocking infrared wavelengths outside this range.

15. The infrared hair dryer according to claim 1, It is characterized in that The thermal inertia of the infrared radiation source (2) allows the infrared radiation source (2) to achieve a temperature of 1000° C. in less than 5 seconds.

16. The infrared hair dryer according to claim 2, It is characterized in that The thickness of the etched foil is between 50 μm and 120 μm.

17. The infrared hair dryer according to claim 2, It is characterized in that The thickness of the etched foil was 100 μm.

18. The infrared hair dryer according to claim 3, It is characterized in that The surface area of ​​the disc-shaped surface is greater than 40 cm 2 .

19. The infrared hair dryer according to claim 6, It is characterized in that The infrared radiation source has a power of 10 W / m 3 power density.

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