FR2784274A1 - Hair dryer comprises electric motor contained in a streamlined shell defining with an inner surface of the housing an air channel with annular cross section continuously and gradually widening, from the turbine towards the heating element - Google Patents

Abstract

The hair dryer (1) has a housing (2) consisting of a suction case (3) containing a centrifuge fan including a turbine (7) associated with an electric motor (8). The housing is connected to a blow nozzle (9) containing a heating element (10). The electric motor (8) is at least contained in a streamlined shell (14) defining with an inner surface (21) of the housing (2) an air channel with annular cross section continuously and gradually widening, from the turbine (7) or from a specific distance (23) from the turbine, towards the heating element (10). The shell (14) is formed by a cylindrical casing extended by a tapered or substantially profiled end part towards the heating element, and the casing external diameter is equal or substantially equal to the turbine external diameter.

Description

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HAIR DRYER

  The present invention relates to a dryer apparatus.

  hair comprising a housing formed by a suction casing containing a centrifugal fan comprising a turbine associated with an electric motor, said casing being connected to a spout

  blowing containing a heating element.

  It finds a particularly important although not exclusive application in the field of professional and / or user hair dryers.

  having fragile hair and scalp.

  Hair dryers with a centrifugal fan and an element are already known

heating.

  The element is made of resistant metal wire wound on a support of insulating material in the form of a cross. To favor the transfer of heat energy, the surface of exchange of the resistant wire with the air current generated by the fan is increased by bending the wire in accordion on itself

  prior to its winding on the support.

  The turns thus formed are then part of a volume delimited on the one hand by a surface of revolution tangent to the outside of the turns, and on the other hand by a surface of revolution tangent to

inside the turns.

  The inside and outside diameters of these surfaces of revolution are also dimensioned.

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  so that the heating element is in the area of

  higher flow rate of the air flow channel.

  This has a first annular cross-section, reduced, delimited by the internal wall of the apparatus and the external ends of the blades of the turbine, a second, annular section, suddenly increased, delimited by the internal wall of the apparatus and the external surface of the engine and, at the interface between the engine and the heating element, a third circular section, still suddenly increased, corresponding overall to the internal section of

the unit there.

  Such hair dryers have

disadvantages.

  Their internal configuration is indeed at the origin of aerodynamic turbulence generating pressure losses which are detrimental to the performance of the device, in terms of air flow.

and noise.

  In addition, with these devices of the prior art, the centrifugal effect of the turbine results in higher air flow velocities near the interior wall of the device, which involves winding the resistant wire of the 'heating element closest to this wall to be in the sections of higher flow. It is then necessary to provide a thermal protection of the wall

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  internal of the device, for example by coating

with mica sheet.

  Furthermore, the evacuation of the calories dissipated by the heating element in an air stream of narrow annular section results in "hot spots" at the outlet orifice of the blow nozzle of the hair dryer. Such hot spots are detrimental to the comfort of the user and the behavior of plastic materials

  constituting the device and its accessories.

  The present invention aims to provide a hair dryer device which meets the requirements of practice better than those previously known, in particular in that it allows the improvement of the air flow inside the device, in particular by reducing the pressure drops, in that it reduces the noise generated and improves the heat exchanges between the heating element and the drying air, which increases the comfort of use of the device, at a cost. lower and a lower requirement on the temperature resistance of materials

of the device.

  To this end, the invention proposes in particular a hair dryer device comprising a box formed by a suction casing, containing a centrifugal fan comprising a turbine associated with an electric motor, said casing being connected to a blowing nozzle containing an element heating, characterized in that the electric motor is at

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  less partly included in a streamlined shell delimiting with the internal face of the housing an air flow channel of annular transverse section increasing continuously and gradually from the turbine or from a determined distance from the turbine, in the direction of the heating element. It will be noted in particular that by providing a faired shell forming a cover for guiding the air flows, the electric motor is isolated and thereby its cooling is reduced, which could have

  cause deterioration by overheating.

  In fact, due in particular to the significant gains observed with the invention, with equal heating power, it has been possible to reduce the power of the

engine and therefore overheating.

  In advantageous embodiments, recourse is had to one and / or the other of the following arrangements: - the shell is formed by a cylindrical shell extended by a conical or substantially conical end portion, faired in the direction of the heating element; the conical or substantially conical end portion is truncated; - The outer diameter of the ferrule is equal to or substantially equal to the outer diameter of the turbine directly located near the ferrule;

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  - The shell is pierced with at least one communication orifice between the space surrounding the engine and the air flow channel; - the faired end portion penetrates at least partially inside the heating element; - The cylindrical shell of the faired shell has on its external face, regularly arranged, blades for rectifying the flow of air, advantageously of length substantially equal to the width of the shell; - the equivalent radius RA (defined below) of the annular section SA located between the cylindrical shell of the shell and the internal wall of the housing, and the equivalent radius RX of the annular section SX, located between the conical end portion , faired, and the internal wall of the housing, at a distance X from the junction between the cylindrical shell and said conical portion, are linked by the following formula: RX2 = RI2 - (RA + kX) 2 with RI: internal radius of the housing at distance X RA2 = Rp2 - RV2 o RP: internal radius of the casing to the right of the ferrule RV: external radius of the ferrule

k: constant.

  - the constant k is such that 0.01 <k <0.125.

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  The invention will be better understood on reading the

  description which follows of given embodiments

  below by way of nonlimiting examples. The

  description refers to the accompanying drawings

  in which: - Figure 1 is a schematic sectional view of a first embodiment of an apparatus according to the invention. - Figure 2 is a cutaway view, in

  perspective, of the apparatus of FIG. 1.

  - Figure 3 is an exploded perspective view of a second embodiment of an apparatus according to the invention.

  Figures 1 and 2 show a dryer

  hair 1 comprising a housing 2, of plastic material of a type known for hair dryers, formed by a suction casing 3 cylindrical or slightly

  tapered towards the rear end of the appliance.

  The casing is open at this end where it has a cylindrical orifice 4 for suction, for example provided with a guide collar 5 of low

  taper formed in one piece with the housing.

  The casing also contains a centrifugal fan 6 of known type, comprising a thin cylindrical turbine 7 (for example 15 mm),

  associated with an electric motor 8.

  The motor is a rotary electric motor, for example with a useful power of 30 Watts, advantageously with a power of between

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  around 15 Watts and around 45 Watts,

  supplied with alternating current from the mains.

  On the other side of the orifice 4, the casing 3 is connected to a blowing nozzle 9 for example formed by a cone with walls flared inwards. The spout 9 contains a heating element 10 constituted by a resistant metallic wire, wound in an accordion on a support 11 made of insulating material and in the form of a cross with four radial branches,

  arranged at right angles to each other.

  The heating element 10 also fits between an outer cone, truncated, with an apex angle between 10 and 80, for example 30 and a

  internal cone with similar taper.

  According to the embodiment of the invention more particularly described here, the heating element is hollow on at least one part 13 located on the side of the engine. The housing of the device contains a shell shell 14 in the form of a shell, made of plastic, which entirely contains the engine.

electric 8.

  Advantageously, the plastic material used is flexible, for example made of elastomer, for example of

SHORE A hardness from 60 to 70.

  This results in excellent noise filtration

and engine vibration.

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  By being integral with the engine mounting lugs, the elastic fairing shell also plays

a role of shock absorber.

  More specifically, the shell 14 is formed of a cylindrical shell 15 in the end of an adjoining side, that is to say is substantially near or directly near the upper edge of the turbine 7, and which is extended on the other side by a substantially conical end portion 16, the walls of which are slightly convex, that is to say at

large radius of curvature.

  The conical portion 16 is directed towards the heating element 10 inside which it penetrates, into

the hollow part 13.

  The cylindrical shell 15 comprises blades 17 regularly arranged around the periphery of the shell, for example twelve or fourteen blades in the form of curved pallets arranged to convert kinetic energy, corresponding to the tangential component of the air flow turbine in turbine outlet, in potential energy of static pressure, usable to overcome the pressure losses of the circuit and consequently improve the aeraulic efficiency in term

air flow.

  The blades also serve as blocking and fixing shims of the ferrule, i.e. the shell

faired in the housing.

  To further improve said flows, the outside diameter of the shell 15 is equal to or

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  substantially equal to the external diameter of the turbine 7. The cylindrical shell 15 also comprises two perforated parts 18, for example rectangular, located on either side of the axis 19 of the device 1, between two blades, and allowing the communication between the space 20 located in the immediate vicinity of the electric motor 8 and / or of its fixing part (not shown) which keeps it in place, and the air flow channel defined by the faired shell 14

  and the internal face 21 of the housing opposite.

  In the embodiment of the invention more particularly described here, the streamlined shell has a profile determined as a function of the profile of the wall

internal device.

  FIG. 2 shows the annular section SA between the turbine 7 and the internal wall 22 of the casing 3 of the apparatus, and the annular section SX located at a distance X from the junction line 23 between the ferrule 15 and the conical portion 16, said annular section being delimited by the external wall 24 of said portion and the internal wall 21

of the beak.

  In other words, this section SX is limited by the circle of radius RX, formed by the external surface of the conical end portion 16 and the radius RI formed by the surface of the internal wall 21

  from the appliance spout to the right of this section.

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  Let RV be the external radius of the cylindrical shell and RP the internal radius of the device in line with the shell, we define a radius RA of a circular section equivalent to the annular section SA such that

RA = RP2- RV2

  We define a coefficient of progression k.

  In the embodiment of the invention more particularly described here, the evolution of the radius RX of the streamlined conical portion as a function of the distance X and the radius RI of the internal wall is then expressed by the formula: = pJ2 - (RA + k) 2 Advantageously, the values of k are less than or equal to 0.13, and for example between 0.075 and 0.125, for example 0.1, which makes it possible to obtain a significant improvement in

air flow.

  Figure 3 shows a hair dryer 30

  according to another embodiment of the invention.

  It comprises a housing 31 formed by a suction casing in two parts 32 and 33, namely a hollow cylindrical part 32, open on either side, provided with an end orifice 34 and a shell 33 in bell-shaped, perforated by regularly distributed grids and detachably snapped onto said cylindrical part 32 opposite

of the opening 34.

  il 2784274 The housing includes a half handle 36 'of

  preemption arranged to cooperate with another half

  36 '' handle as will be described below.

  The apparatus comprises a centrifugal fan composed of a turbine 37 known in itself, adjoining a small substantially cylindrical part 38 supporting the electric motor 39 provided with a shaft

  central actuation of said turbine.

  More specifically, the support comprises two lateral tabs 38 ′ which are inserted into two recesses of complementary shapes themselves formed in two lateral wings integral with the faired shell, extending radially outward from said shell and themselves attached to the body of the

hair dryer housing.

  Thus the two support legs are entirely encompassed by the elastic material of the faired shell of the lateral wings, which allows a

  excellent vibration damping.

  Advantageously, the supports are further extended by profiled ribs in the blade (not

  shown) to improve flows.

  Various elements 40 are associated with the turbine, which will allow its connection to an electric power cable 41 via the handle formed after assembly by the two half-handles 36 ', 36' 'According to the embodiment of the invention more particularly described, the electric motor 39 is included at least in part in a faired shell 42

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  formed of a cylindrical shell 43, comprising blades 44 for straightening the air flow and fixing the shell in the device, and an end portion 45 in substantially conical shape, with a slightly convex wall, as previously described. The substantially conical shape comprises, for example, an openwork part 46 putting the space located near the motor 39 in communication with the air flow channel formed between the faired shell and the internal face of the device, which improves the cooling of the motor 39, without significantly disturbing the air flows and allowing the passage of the electrical supply from the

engine.

  In another embodiment of the invention, the end of the faired hull is open, for example truncated, and connects the space located around the engine with the area external to said

shell.

  Such an arrangement allows better cooling of the engine due to the existence of a low pressure area at the nose of the hull. The device 30 further comprises a blowing nozzle 47 provided with a first cylindrical or substantially cylindrical part 48 arranged to be fixed on the cylindrical part 32 of the casing, the turbine assembly, the motor and the cylindrical shell of the shell.

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  fairing being included in the part of the apparatus formed by the parts or part of part 32 and 48, and a part 49 of frustoconical shape with slightly concave wall. This part 49 advantageously comprises a removable accessory 50 at its end for directing the air jet coming from the drying apparatus

  substantially parallel to a plane.

  The other half-handle 36 '' arranged to cooperate with the half-handle 36 'of the part 32 is also provided to form an entire handle by

  fitting and screwing during assembly.

  The spout 47 internally comprises a heating element 51 comprising a support 52 for example formed by four star branches, on which is wound a heating resistor (not shown), of the type

  that described with reference to FIGS. 1 and 2.

  A part 53 for thermal protection and preventing access to the active parts by a user is

  moreover provided in a manner known per se.

  We will now describe more precisely the operating method of a hair dryer device.

  according to the invention with reference to Figure 1.

  The turbine 7 actuated in rotation by the electric motor 8 sucks the air from the suction opening 4 and rejects it at its

periphery 54.

  The air (arrow 55) is then directed and refocused by the blades 17 in a laminar manner in the channel

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  flow delimited by the internal wall of the housing

  of the device and the faired shell according to the invention.

  The annular section SA at the level of the cylindrical shell and of the turbine, increases for example at first, due to the diverging cone-shaped inclination of the housing above the shell, and then, in the spout of blowing, due to the steeper hull slope than

  that of the wall of the blowing nozzle.

  The laminar nets 56 then lick the heating resistance and make it possible to obtain at the outlet 57 of the spout a laminar air flow.

substantially without hot spots.

  As is obvious and as also follows from the above, the present invention is not limited to the embodiments more particularly described. On the contrary, it embraces all the variants thereof and in particular those where the heating element is constituted by a resistance of a shape different from that more particularly described, that where the blowing nozzle is not in frustoconical shape but is of cylindrical shape, that o the shell shell is not cylindrical

but slightly conical.

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Claims (9)

  1. Hair dryer apparatus (1, -30) comprising a housing (2, 31) formed by a suction casing (3; 32, 33), containing a centrifugal fan comprising a turbine (7, 37) associated with an electric motor (8, 39), said casing being connected to a blowing nozzle (9, 47) containing a heating element (10, 53), characterized in that the electric motor (8, 39) is at least partly included in a faired shell (14, 42) delimiting with the internal face (21) of the housing an air flow channel of annular cross section increasing continuously and gradually, from the turbine (7, 37) or from a determined distance (23) from the turbine,   in the direction of the heating element (10, 53).   2. Apparatus according to claim 1, characterized in that the shell (14, 42) is formed by a cylindrical ferrule (15, 43) extended by an end portion (16, 45) conical or substantially conical,   shrouded in the direction of the heating element.   3. Apparatus according to claim 2, characterized in that the conical end portion or   substantially conical, is truncated.   4. Apparatus according to claims 2 and 3,   characterized in that the external diameter of the ferrule (15, 43) is equal to or substantially equal to the   external diameter of the turbine (7, 37).   5. Apparatus according to any one of   previous claims, characterized in that the   shell (14, 42) is pierced with at least one orifice (18, 46) for communication between the space surrounding the engine and the air flow channel. 6. Apparatus according to any one of   claims 2 to 5, characterized in that the   faired end portion (16, 45) penetrates at least   partly inside the heating element.   7. Apparatus according to any one of   Claims 2 to 6, characterized in that the ferrule   (15, 43) cylindrical of the shell (14, 42) faired has on its outer face of the blades (17, 44) air flow rectifiers, of width   substantially equal to that of the ferrule.   8. Apparatus according to any one of   Claims 2 to 7, characterized in that the radius   equivalent RA of the annular section SA situated between the cylindrical shell (15, 43) of the shell (14, 42) and the internal wall (21) of the housing (2, 31), and the equivalent radius RX of the annular section SX , located between the conical, faired end portion (16, 45) and the internal wall (21) of the housing, at a distance X from the junction (23) between the cylindrical shell and said conical portion, are linked by the following formula: RX2 = RI2 (RA + kX) 2 with RI: internal radius of the housing at distance X 17 2784274 RA2 = RP2 - RV2   or RP: internal radius of the casing to the right of the ferrule RV: external radius of the ferrule k: constant.   9. Apparatus according to claim 8, characterized in that the constant k is such that 0.01 S k 0.125.