WO2017072112A1

WO2017072112A1 - Hair dryer with improved acoustic performance

Info

Publication number: WO2017072112A1
Application number: PCT/EP2016/075665
Authority: WO
Inventors: Frédéric GILSOUL; Olivier Smal; Barry Dobson; Kunal Vyas
Original assignee: Babyliss Faco Sprl
Priority date: 2015-10-27
Filing date: 2016-10-25
Publication date: 2017-05-04
Also published as: EP3367840B1; CN108348060A; ES2817535T3; EP3367840A1

Abstract

The present invention relates to a hair dryer (1) which includes a tubular body along a longitudinal axis with, at the opposite ends thereof, an air inlet and an air outlet, and a turbine (2) located inside said tubular body which, during use, is rotated by a motor (8) about the direction of the longitudinal axis, making it possible to suck in air via the inlet and to discharge air via the outlet of said tubular body, the hair dryer (1) comprising an air-inlet bend (3) comprising one or more blades (4).

Description

HAIR DRYER WITH IMPROVED ACOUSTIC PERFORMANCE Object of the invention

The present invention relates to a hair dryer with improved acoustic performance, and more particularly to a hair dryer with low noise having at its air inlet a hollow tubular elbow equipped with one or more blades.

State of the art

[0002] The hairdryers on the market continue to be relatively noisy despite many efforts on the part of manufacturers to make them quieter. There is therefore a real demand on the part of customers to reduce the noise level and make the spectrum of sound frequencies emitted more pleasant to the ear.

Many attempts have been made in this direction with mixed success because the means available to achieve this goal are limited, especially by budget constraints that do not allow to introduce active noise reduction technologies, such as sound generators in phase opposition, and because of the size and weight of the devices which must remain acceptable to the user.

One of the possible approaches to reduce the noise level of a hair dryer is the positioning at the air intake of a silencer generally consists of a hood equipped with open cell foams or pleated surfaces susceptible to absorb the noise generated by the engine and the flow of air. FR 2 926 704; FR 2 983 043; WO 2010/045698 A1 as well as EP 2 412 272 A1 and EP 2 327 327 A1 belong to this category.

Another approach is that of the decrease in air speed because the noise generated by an air flow in a hollow body is proportional to the speed of power 8 (jet noise). To control this phenomenon, we imagined the use of several successive turbines. This type of arrangement is disclosed in WO 98/49500. US 2015/0237984 A1 discloses a high performance hair dryer with a reduced noise level having an insulating coating lining the inside of the housing. The flow of air at the inlet of the turbine undergoes a particular deviation and the turbine comprises a ring with fins for rectifying a turbulent air flow.

[0007] DE 88 05 910 U1 discloses a hair dryer with a device designed to reduce the noise. The air flow, before passing through the turbine, enters a housing comprising baffles. The housing comprising the baffles is aligned along the same axis as the body of the hair dryer comprising the turbine.

[0008] JP S53 164377 U describes a hair dryer comprising an antechamber located at the rear of a main body including a turbine. The flow from the antechamber to the main body of the device is through baffles to deflect the flow of air before entering the turbine.

To our knowledge, there is currently no on the market a hairdryer constituting a satisfactory compromise between weight, size and manufacturing cost, and acceptable acoustic performance.

Goals of the invention

The present invention aims to provide a hair dryer quieter than the devices of the state of the art, with a sound spectrum whose most troublesome frequencies have been eliminated, and constituting a good compromise between weight, l 'footprint and the cost of manufacture.

Summary of the invention

The present invention discloses a hair dryer comprising:

a tubular body along a longitudinal axis with, at its opposite ends, an inlet and an outlet of air;

- A turbine located in said tubular body which, in use, is rotated by a motor in the direction of the longitudinal axis, which allows to suck the air through the inlet and expel the air by the outlet of said tubular body, characterized in that the hairdryer comprises an air inlet bend having one or more vanes.

Preferred embodiments of the invention comprise at least one or any suitable combination of the following features:

the blades are generally parallel to the curvature of the elbow; the air intake elbow comprises between 3 and 6 vanes, preferably 4 or 5 vanes;

the air intake elbow further comprises one or more partitions dividing the vanes;

the outlet end of said air inlet bend, at the entrance of the core of the hair dryer casing, includes a section restriction, compensating for the section occupied in said bend by said blades; the distance between the blades is set such that the airflow at the outlet of the air inlet elbow and at the entrance of the core of the hair dryer casing has substantially the same speed distribution on all opening diameter;

the turbine has curved blades positioned on a base of substantially conical or frustoconical shape;

between the core of the shell and the turbine, there is a constriction C restricting the passage of air and forcing the air to enter the turbine;

the blades of the turbine are curved at an angle ω between 40 and 60 °, preferably between 45 and 55 °, and particularly preferably between 48 and 53 °;

the turbine is driven by a motor that can be housed at least partially in the hollow portion of the cone supporting the blades of the turbine;

the region of reorganization of the flow (L-organize) of the hair dryer comprises the fins for rectifying the flow of air at the outlet of the turbine;

the air intake elbow has on its inner wall a wall-shaped sound absorption means having openings; the motor is of the brushless motor type. By "generally" parallel means that the vanes are substantially parallel to the curvature of the elbow. At most the blades are parallel to the curvature, the more the air inlet velocity profile is linear over the entire width of the inlet diameter just before the turbine. The ideal position of the blades to reduce the noise of the flow is therefore this parallel position which must be approached to the maximum for an optimal result. The terms "core of the envelope" and "flux reorganization region" define regions of the tubular body of the hair dryer. According to the invention, the tubular body is composed of 3 regions. These are named, starting from the end of the body allowing the entry of air towards the exit end of air, the "heart of the envelope", the "reorganization region of the flow" and the "Air heating zone". The region of the "core of the envelope" (named "L-shroud" in Figure 13) is the region comprising the turbine and which is contiguous to the outlet of the air intake elbow. This region directs the flow of air around the turbine. The "airflow reorganization" region (named "L-organize" in Figure 13) is located at the outlet of the turbine 2, between the core area of the envelope and the heating zone of the 'air. It makes it possible to straighten, thanks to fins, the flow of turbulent air leaving the turbine. Finally, the air flow enters the heating zone to be heated before it leaves the appliance.

By "noise absorption means in the form of a wall", it is meant that the different internal surfaces may comprise means that absorb the noise. The inner parts of the hair dryer may, for example, be coated or lined with sound-absorbing elements, or even wall-like surface effects, such as perforations, openings, open-cell foam or non-fibrous fibers. -woven, etc.

Brief description of the figures

Figure 1 shows a three-dimensional view of the hair dryer according to the invention. The air intake elbow is here integrated into a decorative element drawn in the open position.

Figure 2 shows a simplified drawing of the three-dimensional air intake elbow with three vanes. The part to open the elbow is not shown for the sake of clarity of the figure.

Figures 3 and 4 show the two-part air intake elbow with a central blade for separating the two elements constituting the air inlet elbow.

Figure 5 shows air inlet bends with blades varying in number and positioning. The figure shows examples with 3, 4 and 5 blades which are optimally positioned to generate an approximately linear air inlet velocity profile over the entire width of the inlet diameter just before the turbine. Figures 6 to 10 show different types of air inlet bends according to the invention. These can have shapes ranging from simple geometries to complex geometries that do not meet any precise geometric criteria.

[0021] Figure 1 1 shows an example of possible turbines according to the present invention.

Figure 12 shows the inner casing of the hair dryer housing according to the present invention with fins for rectifying air leaving the turbine. The interior of the ferrule may be lined with a sound absorption coating such as a perforated wall for example.

Figure 13 is a schematic representation of the hair dryer according to the invention which shows the main parameters influencing the flow of air through the device.

Figure 14 is a sectional representation of a preferred embodiment of the hair dryer according to the invention.

List of reference symbols

1. Hair dryer

2. Turbine

3. Air inlet elbow

4. Air inlet elbow vanes

5. Partition dividing the vanes

6. Turbine cone

7. Handle

8. Engine

9. Blades

10. Straightening fins

1 1. Section restriction at the outlet of the elbow and at the inlet of the turbine

Detailed description of the invention

The present invention discloses a hair dryer 1 with improved sound performance including an air inlet bend 3 to reduce certain unpleasant frequencies to the ear, as well as the overall sound level up to 5 dB, of preferably up to 10 dB.

Figure 13 shows all the parameters defined for the construction of the hair dryer 1 according to the invention. For simplification of the illustration of the invention, the apparatus has a symmetry of revolution about a central axis. he It is obvious that another configuration than that of a symmetry of revolution about a central axis is also possible and can be envisaged according to the present invention. This is the reason why we will speak rather of longitudinal axis.

The inlet bend 3 is compartmentalized by one or more blades 4 which substantially follow the curvature of the elbow 3. These vanes are generally 3 to 6. The best results have however been obtained with 4 or 5 blades. Although the air velocities are such as to obtain a Reynolds number classifying the flow of the turbulent flux among the turbulent flows, the vanes 4 straighten the flow of air to make it as laminar and parallel as possible before it does not enter the tubular body of the hair dryer 1. The blades (n = 1; 2; 3; 4; 5; 6 ...) also constitute a sound barrier between the turbine / engine compartment and the outside of the hair dryer 1.

One or more partitions 5 dividing the curved vanes 4 can also have a beneficial effect on the decrease in sound level. A partition 5 vertically dividing the vanes 4 also allows an easier realization of the manufacturing mold which avoids undercuts.

The inlet bend 3 may take different shapes and different regular or irregular curvatures, non-limiting examples are shown in Figures 6 to 10. When the elbow 3 is part of a circle, the angle of the arc formed by the air inlet bend generally varies from 20 to 120 °, preferably from 25 to 90 °, or from 30 to 80 ° and particularly preferably from 40 to 75 °. The axis of the radius of the air inlet elbow may be located near or even far from the apparatus, which directly influences the length of the elbow 3. The elbow 3 may also have a diameter varying along its length and that it can go up or down. All these parameters obviously can vary only by respecting the constraints of space acceptable in practice for a hair dryer.

To straighten the flow of air at the inlet of the turbine 2, the air intake elbow 3 is compartmentalized by the presence of the vanes 4. The distance between the vanes 4 located in the inlet elbow 3 is preferably chosen in such a way that the pressure drop of the air flow through the compartments is the same, which makes it possible to obtain a substantially homogeneous air velocity profile over the entire section. at the air inlet, where there is a section restriction 1 1 to compensate for the section occupied by the vanes 4 and any partitions 5, just in front of the turbine 2.

It is known that the pressure drop in a pipe for a laminar flow depends at least on the length, the section and the perimeter as well as the surface roughness, which is assumed to be the same for all compartments. . This Pressure drop can be calculated by complex formulas involving surface roughness, temperature, flow velocity, etc. The formulas are generally reductive because they are based on simple geometries. In the present invention, however, we are not in the case of a laminar flow and homogeneous air velocity profiles at the outlet of the elbow 3 compartmentalized by vanes 4 could only be obtained experimentally by arranging them. blades 4, and in particular the distances between vanes, empirically by trial and error.

In one example, the air intake elbow 3 is defined in the following table. The value refers to the diameter D = 2R of the base of the cone 6 supporting the blades 9 of the turbine 2. (see Figure 13 where the radius of the cone is indicated)

Table 1: Air Inlet Elbow

As already mentioned above, the air intake in front of the turbine 2 further comprises a restriction of section 1 1 to compensate for the loss of section due to the presence of blades 4 which reduce the effective diameter of the elbow. air intake and which also constitute an obstacle to the flow of air at the entrance of the hair dryer, the aim being that the air flow does not enter a larger effective diameter after having crossed the inlet bend 3.

The turbine 2 has curved blades 9 positioned on a base

6 of substantially conical or frustoconical shape (see Fig.1 1). The level of curvature of the blades is determined by the angle ω (see Fig.13). This angle generally varies from 20 to 50 °, preferably from 25 to 40 ° or from 28 to 37 °, and particularly preferably from 30 to 35 °.

The cone 6 supporting the blades 9 is defined in particular by the angle Θ1 formed with respect to the central axis. It may vary from 45 to 65 °, preferably from 50 to 60 °, and particularly preferably from 53 to 58 °.

A non-limiting example of a turbine 2 for a specific embodiment of a hair dryer 1 is given in the following table. It gives dimension reports and an actual dimension example for the execution mode represented in FIG. 13 with a right cone 6 and a shrinkage C of the envelope around the turbine 2:

Table 2: Turbine

n = the minimum radius of the lower edge of the turbine blades

r ₀ = the maximum outside radius

h = maximum height of the blade from the base of the cone

Θ = semi-angle of the cone with respect to the longitudinal axis of the hair dryer

ω = angle of inclination of the blade relative to the radial direction

The turbine 2 is driven by a motor 8 can be housed at least partly in the hollow portion of the cone 6 supporting the blades 9 of the turbine 2. It will preferably use a brushless motor 8 which will be less noisy than an ordinary engine.

The core of the envelope is the region defined by the exit of the air inlet elbow (L-shroud) before the reorganization of the air flow (L-organize) at the outlet of the turbine 2. This region is very important. It comprises the turbine 2 and determines the flow of air around it. According to a non-limiting example, the core of the envelope is defined as follows:

Table 3: Heart of the envelope

At the outlet of the turbine 2, the air flow is very turbulent, which is unfavorable to the objective of reducing noise. For this reason, the region of reorganization of the flow (L-organize), which starts at the exit of the core of the envelope (L-shroud) and goes to the entrance of the air-heating zone (L-heater), includes fins 10 for rectifying the air flow at the outlet of the turbine 2. These fins 10 are curved towards the direction of introduction of the air leaving the turbine 2 (see Fig.12).

The fins have an angle φ relative to the plane passing through the central axis of about 45 ° (see Figure 13). The function of these fins 10 is to reduce the rotational airflow around the central axis without adding substantial turbulence.

According to a non-limiting example, the reorganization region of the stream is defined as follows:

Table 4: Flux Reorganization Region [0042] The region where the air is heated (L-heater) comprises heating resistors and their support structure. This region begins at the end of the reorganization region of the flow (L-organize) to the exit plane of the device. Insofar as this region is of frustoconical shape and characterized by a diameter decrease at an angle β with respect to the central axis, it accelerates the flow of air.

Table 5: Heating zone

Different inner parts of the housing of the hair dryer according to the invention and in particular the air inlet bend 3 can be upholstered with surfaces or walls absorbing the noise of the air flow and the turbine 2. These surfaces may be perforated partition type, open cell foam or nonwoven fibers etc.

Claims

Hair dryer (1) comprising:

- a turbine (2) located in said tubular body which, in use, is rotated by a motor (8) in the direction of the longitudinal axis, which allows to suck air through the inlet and d expelling the air through the outlet of said tubular body, characterized in that the hair dryer (1) comprises:

- An air inlet bend (3) comprising one or more vanes (4).

2. Hair dryer according to claim 1 wherein the blades (4) are generally parallel to the curvature of the elbow (3).

3. Hair dryer according to claim 1 or 2 wherein the elbow (3) air inlet comprises between 3 and 6 blades (4), preferably 4 or 5 blades (4).

4. Hair dryer according to any one of the preceding claims, characterized in that the elbow (3) of air inlet further comprises one or more partitions (5) dividing the vanes (4).

5. Hair dryer according to any one of the preceding claims, characterized in that the outlet end of said elbow (3) air inlet at the entrance of the heart of the envelope of the hair dryer, comprises a section restriction (1 1), compensating the section occupied in said elbow (3) by said vanes (4).

Hair dryer according to one of the preceding claims, characterized in that the distance between the vanes (4) is set in such a way that the air flow at the outlet of the inlet elbow (3) air and at the entrance of the heart of the hair dryer casing (1) has substantially the same speed distribution over the entire opening diameter.

7. Hair dryer according to any one of the preceding claims, characterized in that the turbine (2) has blades (9) curved positioned on a base of substantially conical or frustoconical shape.

8. Hair dryer according to any one of the preceding claims, characterized in that between the core of the casing and the turbine (2), there is a constriction C restricting the passage of air and forcing the air to enter the turbine (2).

9. Hair dryer according to any one of the preceding claims, characterized in that the blades (9) of the turbine (2) are curved according to an angle ω between 40 and 60 °, preferably between 45 and 55 °, and particularly preferably between 48 and 53 °.

10. Hair dryer according to any one of the preceding claims, characterized in that the turbine (2) is driven by a motor (8) which can be housed at least partially in the hollow portion of the cone (6) supporting the blades of the turbine (2).

11. Hair dryer according to any one of the preceding claims, characterized in that the reorganization region of the flow (L-arrange) of the hair dryer comprises the rectifying fins (10) of the air flow at the outlet of the turbine (2).

12. Hair dryer according to any one of the preceding claims, wherein the elbow (3) of air inlet has on its inner wall wall-like sound absorption means having openings.

13. Hair dryer according to any one of the preceding claims wherein the motor (8) is of the brushless motor type.