WO2001090654A2

WO2001090654A2 - Appliance for heating a fluid such as in particular depilatory wax

Info

Publication number: WO2001090654A2
Application number: PCT/FR2001/001583
Authority: WO
Inventors: Marc Legrain; Thierry Maunier
Original assignee: Seb S.A.
Priority date: 2000-05-24
Filing date: 2001-05-22
Publication date: 2001-11-29
Also published as: AU7413301A; FR2809480A1; WO2001090654A3

Abstract

The invention concerns an appliance (1) for heating a fluid, comprising a reservoir (5) temporarily coupled to a base (2), said reservoir (5) being designed to contain said fluid to be heated; means (10) for heating said reservoir (5); means for controlling (17) said heating means (10) including a temperature sensor (20) capable of generating an information representing the temperature of the fluid to be heated, said temperature sensor comprising: means for transmitting (21) an electromagnetic wave beam; means for reflecting (22) said beam; means for receiving (23) said reflected beam, the transmitting (21) and the receiving (22) means being located on the base (2) of the appliance, and the reflecting means (22) being located on the reservoir (5), opposite said transmitting (21) and receiving (22) means. The invention is characterised in that the reflecting means change shape when the reservoir temperature varies.

Description

APPARATUS FOR HEATING A FLUID SUCH AS IN PARTICULAR EPILATORY WAX

Technical area

The invention relates to the field of household appliances in general. It relates more particularly to an apparatus intended for heating a fluid contained in a tank that can be disconnected from a base. It finds a very particular application in waxing devices. Although not limited to this particular use, the invention will be described below more specifically in its application to wax applicators.

Previous techniques

In known manner, the apparatuses of the wax applicator type comprise a reservoir which contains the molten wax. This reservoir has a nozzle for depositing the wax on the areas to be depilated. This tank is equipped with a heating resistance allowing the wax to pass from the solid state to a liquid state for the application. The wax must be kept at a temperature sufficient to remain in a liquid state necessary for its application. However, it must not be overheated, otherwise the user may be burned and the properties of the wax may be degraded. The wax applicators therefore include a temperature regulation system making it possible to limit and regulate the temperature of the body to be heated.

For practical reasons, most of the devices of the wax applicator type comprise a reservoir which is disconnectable from a base, itself connected to a source of electrical energy.

The mechanical interface between the base and the tank includes electrical connections making it possible to supply the heating resistance. Several architectures have been proposed in which the temperature regulation device can either be mounted inside the tank, or be an integral part of the base. Thus, in the case where the regulating device is located in the removable tank, it is necessary to re-establish the electrical connection between the energy source and the regulating device each time the tank is replaced in place on the base.

It is understood that this arrangement induces many drawbacks since it is necessary to ensure particularly precise alignment between the electrical connection zones of the tank and the base. When the base contains a transformer, intended to lower the mains voltage, the passage currents between the base and the tank are greater, and this induces stresses at the level of the connections of the mobile element of the base. The large currents require that the connection zones between the mobile part and the base be of larger dimensions, which results in friction during the positioning operations, and therefore an effort to be exerted on the part of the user. .

Some devices include mechanical disconnection mechanisms, ensuring a separation of the various contacts of the tank and the base before the tank is extracted. These mechanisms are generally controlled by the actuation of a push button which induces an additional operation to be carried out by the user, and reduces the advantage of having a removable tank.

In the case where the regulating device is included inside the base, it is necessary to ensure the measurement of the temperature of the wax each time the reservoir is replaced in the base. Thus, at each installation, the regulating device must detect the replacement of the tank, then generate a sequence of temperature measurements, to decide whether the heating resistor should be supplied or not. Even using temperature sensors having a very low inertia, a more or less long time is necessary to effect the acquisition of this temperature, which delays the actuation of the heating resistor and therefore the provision of the apparatus. A first problem which the invention proposes to solve is that of the rapidity of the detection of the temperature of the wax to be heated, as soon as the reservoir is placed in the base.

Furthermore, when the temperature sensor is mounted on the base, the latter does not measure the temperature of the wax itself, but rather that of the reservoir which contains it. This temperature is captured by a contact zone between the base and the corresponding part of the tank. It is understandable that variations in the force of plating of the reservoir on the base, or misalignments, generate errors or at least variations in the temperature measurement, which inevitably result in a functioning of the regulation which does not is not optimal.

Another problem which the invention sets out to solve is that of the dependence of the temperature measurement on the mechanical conditions for placing the mobile part in the base when the latter contains the means for measuring the temperature.

The objective of the invention is therefore to provide an apparatus for heating a fluid, which combines both the advantages of wireless devices, which are easy to handle, and which nevertheless remains very efficient as regards the precision of the regulation. heating while being relatively insensitive to variations in tank pressure on the base and the mechanical quality of the contact.

Statement of the invention

The invention therefore relates to an apparatus intended for heating a fluid, comprising:

. a tank temporarily coupled to a base, said tank being intended to contain said fluid to be heated;

. means for heating said tank;

. control means of said heating means including a temperature sensor capable of generating representative information the temperature of the fluid to be heated, said temperature sensor comprising:

. means for emitting a beam of an electromagnetic wave; . means for reflecting said beam; . means for receiving said reflected beam, the transmitting and receiving means being located on the base of the apparatus, and the reflecting means being located on the tank, opposite said transmitting and receiving means, and in which the reflecting properties of said reflecting means are a function of the temperature of the fluid to be heated, so that the analysis of the reflected beam received by the receiving means makes it possible to determine the temperature of the fluid to be heated.

This device is characterized in that said reflection means change geometry when the temperature of the tank varies.

In other words, the sensor allowing the detection of the temperature of the tank consists of several elements distributed both on the base and on the tank itself. Thus, when the temperature of the reservoir varies, the reflecting part which it is associated with changes its geometry, and reflects the beam which has been emitted from the base in a different manner. The receiver of the beam thus reflected, which is located on the base, receives a beam whose incidence, or intensity or another parameter, varies according to the geometry of the reflecting zone of the mobile part of the device. . Thus, the determination of the temperature of the tank is obtained without mechanical contact between the tank and the base. In this way, the detection of the temperature can be done whatever the plating force of the movable part on the base. The constraints of proximity of the mobile part relative to the base are greatly reduced, which facilitates the design and manufacture of such devices.

Thanks to the constitution of the temperature sensor, it is possible to differentiate the situations in which the movable part is absent from the base, compared to the situation where it is placed there, and whatever its temperature.

Advantageously in practice, the reflection means can be constituted by a part of the bottom or a side wall of the reservoir, on which the light beam emitted at the base is reflected.

Advantageously in practice, the reflection means can be constituted by a deformable zone incorporated in the bottom or a side wall of the tank, and the geometry of which varies as a function of the temperature of said tank so as to vary the angle of reflection of the beam. feature.

Advantageously, this deformable zone can be attached to the bottom or a side wall of the tank.

In a particular form, the deformable zone can marry a cup shape, for example marrying a shape of a spherical cap, whose geometry, and more precisely the curvature varies according to its expansion.

In other embodiments, the deformable area can be a shape memory element associated with a reflective surface. In this case, the shape memory element follows a geometry which is a function of the temperature of the medium in which it is immersed, this variation in geometry resulting in a variation in the angle of inclination of the reflecting surface and therefore a variation of the signal received at the base.

In another embodiment, the deformable zone can be constituted by a bimetallic strip which deforms as a function of temperature thanks to the difference in expansion of the components which constitute it.

In another embodiment, the reflection means can be constituted by a member located inside the tank, insofar as the walls of the tank are transparent to the waves of the light beam. The different architectures mentioned can be used, namely deformable cup or even shape memory material or bimetallic strip.

Depending on the case, the reception means may be sensitive to the presence or absence of a reflected signal, so that the regulation can operate in all or nothing. In another preferred case, the variation of the reflective properties will result in the variation of the flux received by the reception means. The received signal will therefore be proportional to the stream received, which will allow proportional regulation, for example of the PID type.

As already said, the invention will find a very particular application in devices for heating depilatory wax, but it is in no way limited to this particular application.

Brief description of the figures The manner of carrying out the invention, as well as the advantages which result therefrom, will emerge clearly from the description of the embodiment which follows, in support of the appended figures in which:

Figure 1 is an overall explanatory diagram of an apparatus according to the invention. Figure 2 is a schematic detail view of the characteristic temperature sensor, produced according to a first alternative embodiment.

FIGS. 3a and 3b are schematic diagrams illustrating the variation in the geometry of the reflected signal as a function of the variation in temperature of the reservoir, in the first alternative embodiment. FIG. 4 is a diagram showing:

. on the abscissa the temperature of the tank,. and on the ordinate the intensity of the reception signal. FIG. 5 is a detailed diagram of the characteristic sensor produced according to a second alternative embodiment. FIGS. 6a and 6b are schematic diagrams illustrating the variation in the geometry of the reflected signal as a function of the variation in temperature of the reservoir, in the second alternative embodiment. FIG. 7 is a diagram showing: . on the abscissa the temperature of the tank,

. and on the ordinate the intensity of the reception signal, in accordance with the second variant of execution. Figures 8 and 9 are detailed views of the sensor made according to two other alternative embodiments.

Way of realizing the invention

As already said, the invention relates to an apparatus intended for heating a fluid which will be described by way of example as a depilatory wax applicator.

Thus, as illustrated in FIG. 1, such an apparatus (1) comprises a base (2) having a housing (3) inside which can be placed a movable part (4) including the reservoir (5) of wax. The movable part (4) has walls (6) surrounding the tank (5) so as to protect the user from the heat of the tank (5). The movable part (4) also has an applicator member (7), which, as in the illustrated case, may consist of rollers, a part (8) of which may come into contact with the molten wax.

The reservoir (5) comprises an electrical resistance (10) which can be constituted, as in the form illustrated by a ribbon or a coil, which is placed directly inside the reservoir (5) so as to be able to exchange a maximum heat with the wax with which it comes into contact.

The two terminals (12, 13) of this resistor (10) are connected to electrical connections forming plugs which are inserted when the mobile part (4) is in place in the base (2), inside complementary female studs (14, 15) integral with the base (2). These studs (14, 15) are connected to a regulation unit (17) whose function is to supply the resistance (10) according to the phases of use of the device. This regulating device (17) is connected by a suitable cord (18) to the sector allowing the energy supply.

The determination of the different operating phases depends for essential way of measuring the temperature of the wax. The wax must in fact first be brought to a sufficient temperature so that it can be applied to the areas to be depilated. It must then be maintained at a determined temperature so that it can retain its depilatory properties.

The invention relates more precisely to the measurement of this temperature which is carried out by a particular sensor (20) including a light source (21), a reflecting area (22) and a receiver (23) of the reflected beam.

As can be seen in FIG. 2, the sensor (20) therefore comprises a light source (21) which may consist of a light-emitting diode, or even any other form of light source and more generally of a wave electromagnetic, which may be outside the visible spectrum. The light source (21) is installed so that its preferred axis (24) has a certain incidence (β) relative to the general plane (26) forming the bottom of the tank. This light source (21) is supplied by the regulation device (17). The light source (21) can be supplied either continuously or alternatively sequentially, depending on the type of regulation and the refresh rate of the temperature information. The base (2) also includes a light receiver (23), sensitive to the same range of waves as that emitted by the source (21).

The privileged axis (29) of sensitivity of the receiving element (23) is oriented in such a way that it corresponds substantially to the reflection relative to the bottom (26) of the reservoir of the privileged axis (24) of the source. (21).

As illustrated in FIG. 2, the bottom (26) of the tank comprises an area on which the beam coming from the source (21) is reflected. In the form illustrated in Figure 2, this area consists of a spherical cup (27) or of substantially similar geometry. As illustrated in FIG. 2, when the cup (27) is at a temperature, the incident beam is reflected in such a way that it is substantially centered around the privileged axis (29) of the receiving element (23).

The different geometric parameters, namely:. the radius of curvature of Ri of the cup (27); . the distance (a) between the light source (21) and the bottom of the cup (27); . the distance (b) between the bottom of the cup (27) and the receiving element

(23); . the half-angle (α) of opening of the emitted beam (30); . the incidences (β) and (χ) of the privileged axes (24, 29) of the source (21) and of the receiver (23); are determined according to the different laws of optics, the type of transmitter and receiver, and the reflecting materials.

The cup (27) disposed in the bottom (26) of the tank is deformed according to a known temperature law. When the reservoir is cooler, the cup (27) is in a concave configuration illustrated in FIG. 3a, so that the reflected beam (30) is almost centered on the receiving element (23). When the tank (5) is warmer, the cup (27) tends to deform so that it adopts a convex configuration as illustrated in FIG. 3b. The reflected beam (30 ') is then divergent and the receiving element (23) receives less light.

The radius of curvature Ri of the cup (27) therefore varies as a function of the temperature. The reflected beam (30) therefore sees its geometry also vary depending on the temperature. The light flux received by the receiving element (23) therefore varies as a function of the temperature. The signal from the receiving element (23) is therefore representative of the temperature of the tank (5). The various dimensional parameters listed above are chosen according to the law of deformation of the cup (27) in temperature so that the information reaching the receiving element (23) is relevant over the largest part of the temperature range. . FIG. 4 illustrates the variation of the signal (S) generated by the receiving element (23) as a function of the temperature of the cup (27). Thus, when the substantially spherical cup (27) is deformed, there is a temperature Ti above which the increase in temperature does not cause additional deformation on the cup, so that the signal received by the receiving element ( 23) is identical for all higher temperatures.

The variation of the signal (S) generated can be linear (curve 34 in dotted lines) or non-linear (curve 35 in solid lines) depending essentially on the law of temperature deformation of the cup (27).

FIG. 5 illustrates a second alternative embodiment in which the cup has been replaced by a bimetallic strip (40) placed under the tank (5). This bimetallic strip (40) has a junction zone (41) with the bottom (26) of the tank. This bimetallic strip (40) is chosen so that its range of deformation corresponds to the temperature range of the tank. The face (42) of the bimetallic strip oriented towards the base (2) is reflective, so as to ensure the reflection of the signal (30) emitted by the source. In the same way as with the cup in FIG. 2, the different dimensional parameters concerning the distance of the sources from the reservoir and the angles of opening and incidence of the beams are determined according to the law of deformation with the temperature of the bimetallic strip.

As can be seen in Figures 6a and 6b, when the tank (5) rises in temperature, the bimetallic strip (40) which is thermally connected to it deforms by moving away from the bottom (26) of the tank. It follows that the reflected beam (43 ') deflects differently, to an angle in which it no longer reaches the receiving element (23) (see Figure 6b).

Thus, as illustrated in FIG. 7, beyond the temperature Ti corresponding to this maximum deviation, the output signal (S) of the reception element (23) is almost zero, or corresponding substantially to the level of the light room. Different geometries and constitutions of bimetal can be chosen so that the output signal of the reception element varies according to the two curves illustrated in FIG. 7. Thus, in a first geometry, (corresponding to the curve (46) in solid lines), the variation is not linear. Conversely, the curve (47) in dotted lines in FIG. 7 illustrates an almost linear variation as a function of the temperature.

FIG. 8 illustrates a third alternative embodiment derived from that of FIG. 2 in which the reflecting cup (50) does not constitute a part of the bottom (26) of the tank, but is on the contrary embedded in the inside of the tank (5 ). In this case, the beam (30) emitted by the light source (21) crosses the bottom (26) of the tank to be reflected on the reflecting surface of the cup (50), and, after having crossed the bottom (26) from the tank, move towards the receiving element (23). In this case, the bottom (26) of the tank must not oppose the passage of the light beam, and must therefore be transparent for the range of waves used. More generally, the source can emit electromagnetic waves in a very broad spectrum, not only limited to the visible spectrum, and the bottom of the reservoir must have a very good transmission coefficient in the range of waves considered.

In this case, the various dimensional parameters of the sensor are also a function of the material used for the bottom (26) of the tank and of the possible wax located between the cup (50) and the bottom (26) of the tank.

In a fourth alternative embodiment in FIG. 9, provision can be made for placing the bimetallic strip (54) used in the mode illustrated in FIG. 5, inside the tank. In this case, the face (55) of the bimetallic strip (54) facing the bottom (26) of the tank is reflective.

Referring again to FIGS. 1 and 2, when the user connects the appliance to the mains, and there is no wax cartridge, the output signal (S) from the receiving element ( 23) depends on the ambient brightness, since the transmitted signal is not reflected. The regulating device can therefore detect the absence of the removable tank. As soon as the user deposits the mobile part on the base, the reflective cup reflects a large part of the signal emitted. The receiving element (23) therefore sends a signal to the regulating device (17) corresponding to a situation in which the temperature of the reservoir is at a low level since the wax is cold. Consequently, the regulating device supplies the heating resistor with a maximum power, corresponding to the heating phase. As the temperature rises, the cup (27) deforms, and by an analysis of the variation of the output signal, typically with a PID regulator, it is possible to measure the energy to reach in time the shorter the setting of the wax at the right temperature.

When the cup (27) is strongly deformed, the emitted beam is reflected so that a minimum of light reaches the receiving element (23). The regulating device therefore detects the temperature value reached and supplies the heating resistor corresponding to a maintenance and temperature-maintaining heating.

Note that as soon as the mobile part is replaced on the base, the receiving element (23) is immediately turned on by the beam (30) which is reflected. The regulating device (27) therefore knows the temperature of the tank without delay, and can therefore determine the amount of energy necessary for optimal operation.

Advantageously, it is possible to set up several different removable parts, comprising for example several specific dispensing tips dedicated to different depilation zones (legs, armpits, bikini line, down, eyebrows), without disturbing the feeding cycle. , since the regulating device immediately knows the temperature at which the corresponding mobile part is located.

It appears from the above that the device according to the invention has multiple advantages, and in particular instant determination the temperature of the tank to be heated. The supply of the heating resistor is therefore almost immediate as soon as the mobile part is replaced on the base. The supply of this electrical resistance is ensured at the optimum value according to the temperature thus detected. In addition, depending on the signal received, it is possible to possibly detect a state of cleanliness of the underside of the tank.

Industrial applications Although more specifically described in the application to depilatory apparatuses with wax, the invention relates to multiple apparatuses for heating a fluid such as in particular fryers, kettles, coffee makers, etc.

Claims

1 / Apparatus (1) intended for heating a fluid, comprising:

. a tank (5) temporarily coupled to a base (2), said tank (5) being intended to contain said fluid to be heated;

. means (10) for heating said tank (5); . control means (17) of said heating means (10) including a temperature sensor (20) capable of generating information representative of the temperature of the fluid to be heated, said temperature sensor comprising:

. means for emitting (21) a beam (30) of an electromagnetic wave; . means for reflecting (22) said beam (30); . means for receiving (23) said reflected beam (31), the transmitting (21) and receiving (23) means being located on the base (2) of the apparatus, and the reflecting means (22) being located on the tank (5), facing said emission (21) and reception (23) means, and in which the reflective properties of said reflection means (22) are a function of the temperature of the fluid to be heated, so that the analysis of the reflected beam (31) received by the reception means (23) makes it possible to determine the temperature of the fluid to be heated, characterized in that said reflection means change geometry when the temperature of the reservoir varies.

2 / Apparatus according to claim 1, characterized in that the reflection means are constituted by a part of the bottom or by a part of a side wall of the tank (5).

3 / Apparatus according to claim 1, characterized in that the reflection means are constituted by a deformable zone incorporated in the bottom or in a side wall of the tank (5).

4 / Apparatus according to claim 3, characterized in that the deformable zone is attached to the bottom or one of the side walls of the tank.

5 / Apparatus according to claim 3, characterized in that the deformable area follows a cup shape (27).

6 / Apparatus according to claim 3, characterized in that the deformable area is a shape memory element associated with a reflective surface.

Il Apparatus according to claim 3, characterized in that the deformable area is a bimetallic strip (40).

8 / Apparatus according to claim 1, characterized in that the reflection means are constituted by a member (50, 54) located inside the tank, the walls of the tank being transparent to the waves of the beam emitted by the means of program.

9 / Apparatus according to claim 1, characterized in that the control means (17) comprise means capable of determining the variation of the signal from the reception means.

10 / Apparatus according to one of claims 1 to 9, characterized in that it is intended to heat depilatory wax.