GB2604332A

GB2604332A - A depilatory wax heating device

Info

Publication number: GB2604332A
Application number: GB2102457.5A
Authority: GB
Inventors: Indar Ragbir Jai
Original assignee: DEO BEAUTY PRODUCTS Ltd
Current assignee: DEO BEAUTY PRODUCTS Ltd
Priority date: 2021-02-22
Filing date: 2021-02-22
Publication date: 2022-09-07
Also published as: GB202102457D0

Abstract

A depilatory wax heater device has a housing comprising an outer wall, inner wall and a base. The inner wall of the housing and the base form a cavity within the device which may receive a container. The device further comprises a control circuit 20 connected electrically to a heating element 26. A temperature sensor 30 provides electrical signals to the controller. A clock module 24 and timer and a programme switch (not shown) also provide electrical signals to the controller to control supply of electrical power to the heating element. Pre-determined factors, such as a maximum temperature, a minimum temperature, a preferred temperature or a maximum temperature rate, also influence the control of the power supply. The heating element may control the device to supply power in accordance with a pre-determined profile, and the pre-determined factors can over-ride the pre-determined profile. The temperature sensor 30 may be located between the base of the housing and the base of the container. It may be arranged to measure the temperature of the container. The control circuit can preferably recognise a variation in the rate of change of the temperature of the container.

Description

A DEPILATORY WAX HEATING DEVICE

Field of the invention

[0001] The present inventive concept relates to a heating device for depilatory wax.

Background to the invention

[0002] Hair removal using wax is a well-established concept and method; and one of many methods for removing hair from the human body. Waxing services are generally provided by professionals due to the difficulty in removing hair from parts of the body which are not easily reached. Furthermore, efficient and safe waxing is a skill best provided by trained and experienced professionals.

[0003] While the concept of wax depilation is simple -a small amount of liquid wax is spread on the skin, allowed to harden, then removed taking underlying hair away -the wax must be prepared and handled carefully. If the wax is too cool when applied then it will not be possible to spread the wax on the subject's skin before it hardens. Alternatively, of the wax is too hot then it may burn the subject's skin [0004] Thus, it is important that a wax heater is able to precisely, reliably and predictably control the temperature of wax to be provided.

[0005] Known wax heaters of this type tend to simply have a temperature selection control and a thermostat. Thus, when such a heater is switched on, power is supplied to a heater until the heater reaches a selected temperature.

However, while such known heaters have advantages in simplicity they also present disadvantages to the professional practitioner, some of which will be discussed below.

Summary of invention

[0006] Accordingly, the present inventive concept is directed to a depilatory wax heater device having a housing comprising an outer wall, inner wall and a base at substantially a bottom of the inner wall, the base having at least an upper surface; wherein the inner wall of the housing and the upper surface of the base form a cavity within the device; the device further comprising a control circuit connected electrically to a heating element, a primary temperature sensor, a clock, a timer and a programme switch, wherein the control circuit is adapted to receive an electrical signal from each of the primary temperature sensor, clock, timer and programme switch and adapted to control supply of electrical power to the heating element according to the said electrical signals and according to one or more pre-determined factors, wherein the pre-determined factors comprise: maximum temperature; minimum temperature; preferred temperature; and maximum rate of temperature change.

[0007] The terms "base", "upper", "bottom" etc. refer in general terms relative to a preferred orientation of the device in use. However, the terms are not intended to be limited to strict horizontal arrangements, in that the device may be placed on a surface which does not provide for a strictly horizontal base -for example -but which still provides for the device to function in substantially the way intended. Similarly, the term "wall"kjm refers in general terms to a substantially vertical member but is not intended to be strictly limited. Thus in use the device will preferably have a cavity formed by a substantially vertical inner wall and a substantially horizontal base at substantially the bottom of the inner wall, and preferably the cavity will be open at substantially a top of the inner wall.

[0008] The cavity may be of substantially uniform cross-section along a vertical axis of the cavity. Preferably, the cavity has a substantially circular cross-25 section.

[0009] The cavity may be adapted to receive a container. The container may have a container base and container wall. The container may be sized and shaped appropriately to fit within the cavity. The container may be removably placed within the cavity of the device, in use.

[0010] The container may be used to contain wax for use in depilation.

[0011] The container may have a flanged portion at an end away from the container base, for example an upper end of the container in use. Such a flanged portion may provide the container with a portion which has a larger diameter than the diameter of the cavity. Thus, the container may be prevented from being lowered into the cavity beyond a certain extent.

[0012] The heater device may further be provided with a removable lid. The removable lid may be placed, in use, substantially on or at a top of the device to close an open, upper, end of the cavity. The lid may be removably attached to the heater device by way of a screw thread. Furthermore, the device and/or the lid may be provided with a resiliently deformable sealing element, such as of plastics or silicone.

[0013] The primary temperature sensor may be an infrared radiation detector.

It is well-known that objects emit electro-magnetic radiation according to their temperature. Therefore, an infrared radiation detector can be used to establish the temperature of an object. An advantage of using an infrared radiation detector as the primary temperature sensor is that such a detector need not be physically adjacent to the object, the temperature of which is being measured. Such an arrangement is advantageous as the detector itself can be to an extent protected from high temperatures by being located physically separately from the said object or can be provided with insulation material or the like. Furthermore, infrared radiation detectors may be arranged to receive radiation from a finite field of view. Thus in contrast to a regular thermometer which will generally measure the temperature of a discrete point location, an infrared radiation detector may be adapted to measure the temperature of a finite portion of a surface of the said object. In such an arrangement, an "average" temperature of the finite portion can be derived; meaning that a useful measure of a temperature can be made of an object which has a temperature distribution across a portion of a surface thereof.

[0014] The field of view of the primary temperature sensor may be selected to include a portion of the container base, when the container is arranged within the cavity.

[0015] Thus, the primary temperature sensor may be located between the base of the housing and the base of the container, for example in use. However, as noted earlier, preferably there is a finite gap between the primary temperature sensor and the base of the housing.

[0016] The container will normally be placed in the cavity when the device is in use, for example. In use, the container may have a quantity of wax arranged within it.

[0017] The primary temperature sensor may be a thermopile.

[0018] The control circuit may be adapted to receive a temperature signal from the primary temperature sensor at regular intervals. If temperature signals are provided frequently, the control circuit may be able to respond rapidly to changes in temperature. Furthermore, calculations of the rate of change of temperature may be made by the control circuit. In a preferred arrangement, the control circuit is adapted to receive a temperature signal from the primary temperature sensor at approximately 12 to 15 times per second.

[0019] The primary temperature sensor may comprise more than one discretely-located temperature sensors working in parallel to provide a temperature signal to the control circuit. Alternatively or additionally, one or more further temperature sensors may be provided.

[0020] The skilled reader will appreciate that usefully measuring and controlling a temperature of wax is difficult due to at least the latent heat of fusion of the said wax. In other words at a phase change between solid and liquid, energy will be absorbed by the wax without there necessarily being a measurable change in the temperature of the wax. Similarly, at a phase change between liquid and solid, energy will be released by the wax. In the present situation, in which the wax is desirably kept only slightly above its melting point, it is therefore advantageous to measure the temperature of a proxy such as the container.

[0021] As an example -bearing in mind that the relationship between container temperature and wax temperature will vary depending on the precise configuration of a device, the type of wax used, the amount of wax present and other factors -the container may be at approximately 70 to 80 Celsius (°C) when the wax is at approximately 50 to 60 Celsius.

[0022] At and around the phase change temperature of the wax, the rate of change of temperature of the container for a given supply of power to the heating element will vary. Thus, the control circuit may be adapted to recognise a variation in the rate of change of temperature of the container. Thus, the control circuit may be able to infer melting of the wax within the container.

[0023] In use, it is desirable for the device of the present inventive concept to provide melted wax at a preferred pre-determined temperature, so that the wax may be used in depilation.

[0024] One approach -an approach applied especially in respect of prior art wax heaters -may be to supply a constant level of electrical power to the heating element. Such an approach would lead over time to an equilibrium temperature being reached, at which the heat supplied by the heating element is in balance with the heat lost to the environment -for example by convection, conduction and/or radiation. Thus, a pre-determined preferred temperature for the wax -or the container -may be achieved by supplying electrical power to the heating element at a pre-selected constant level. However, the time it takes for wax in the container to reach the preferred temperature will inevitably vary according to the amount of wax present in the container and other factors such as the composition of the wax itself, its melting point and its latent heat of fusion, for example. Thus, this approach may have a drawback in that the time taken for the wax to reach the preferred temperature may be long and unpredictable.

[0025] The device of the present inventive concept provides for the control of electrical supply to the heating element according to pre-determined factors.

[0026] The pre-determined factors may include one or more of the following factors: maximum temperature; minimum temperature; preferred temperature; maximum rate of temperature change.

[0027] Furthermore, the control circuit may be adapted to control the heating element according to one or more pre-determined profiles. A profile may include a description of a preferred variation of temperature over a period of time. For example, a profile may describe a change of temperature from an ambient or starting temperature to a preferred temperature over the course of a number of minutes. Alternatively or in addition, a profile may describe a temperature path which increases initially to a temperature above a preferred temperature and then reduces subsequently so that the said preferred temperature may be achieved.

[0028] The higher the initial temperature' the faster wax will melt. However, in practice there is an upper limit to such an initial temperature which is governed by factors such as the characteristics of the wax itself, the heating element, the control circuit, and considerations of health and safety.

[0029] In one example, the container temperature may be increased relatively quickly to approximately 120 Celsius for 15 to 20 minutes, then subsequently reduced to and stabilised at approximately 60 to 80 Celsius. in this example, the wax is ready to use in around 35 minutes from starting the profile.

[0030] Thus, the time required to bring the wax from the ambient temperature to a preferred temperature for use may be reduced compared with the prior art.

[0031] The control circuit may further be adapted to provide one or more overrides in which pre-determined factors may override a pre-determined profile. For example, if the application of a profile results in the temperature of the container approaching or reaching a maximum temperature then the control circuit may automatically respond by reducing the electrical supply to the heating element to prevent the maximum temperature being exceeded. Similarly, if the application of a profile results in the rate of change of temperature approaching or reaching a maximum temperature then the control circuit may automatically respond by reducing the electrical supply to the heating element.

[0032] The control circuit may be adapted to activate a visual and/or aural indicium when a certain condition is met. For example, if the temperature of the container is above the preferred temperature -during implementation of a particular profile for example -then an indicium may be activated so that a user knows not to use the wax. A plurality of indicia may be provided, each indicium being activated under a pre-determined condition. Thus, by assessing the or each indicium, a user should be able to determine whether or not it is safe to use wax contained in the device.

[0033] The clock may be used to enable the control circuit to provide electrical power to the heating element at a pre-determined time of day, and/or on pre-determined days of the week. In other words, the device may be set up in advance to begin heating at a pre-determined time of day. Thus a user is able to set the device up to be at the preferred temperature at a desired time. Given the lead time usually involved in the heating of depilatory wax to a desired temperature, this enables a user to have said wax ready for use in advance. For example, the device may be set up so that the said wax is ready for use at the start of business hours without a user needing to manually switch on the device ahead of business hours to begin the heating process. Furthermore, the clock may store a weekly profile, so that the device is switched on to begin heating at different times of the day on different days of the week, or not at all -for example if the device is not to be used on certain days such as weekends, or at different times where weekly opening time differ.

[0034] Furthermore, the clock may be used to switch the device off at the end of the day. The clock may be provided with an auxiliary power supply such as batteries, so that even when the heating device is switched off, the clock maintains the correct time and date. The batteries may be rechargeable.

[0036] Therefore, the predetermined-profile may comprise a time profile, wherein the control circuit is adapted to control supply of electrical power to the heating element to switch on or off the heating element when the clock indicates one or more pre-set time.

[0036] The clock may keep time of day, and/or day of week information, and the time profile may comprise switching on and switching off times for each day 20 of the week.

[0037] The timer may be used in the implementation of a pre-determined profile. For example, a profile may include the supply of a particular level of power to the heating element for a particular period of time. The timer may enable the precise implementation of a profile.

[0038] Thus, a profile may be started at a pre-determined time of day in advance of a user's arrival at a place of business and may provide for a reduced time needed to prepare wax for use.

[0039] The heating element may comprise a substantially annular band. In other words, the heating element may be substantially a loop having a vertical height significantly larger than a horizontal thickness. The heating element may be substantially co-axial with the cavity. The heating element is preferably located at the lower end of the cavity, i.e. towards the base of the device. However, the

B

heating element is preferably not located at the base itself. Such an arrangement aims at ensuring that the heating element coincides with a location of wax within the container, while avoiding direct contact with the base thus aiming to improve the accuracy of a temperature measurement made by the primary temperature sensor.

[0040] The heating element may be a resistive device. Alternatively, the heating element and container may form an electro-magnetic induction relationship.

[0041] The heating element may be approximately between 25 and 35 mm in vertical height. The heating element is preferably arranged so that it substantially circumferentially surrounds the container when the container is place in the cavity, for example for use.

[0042] The device may further comprise a master switch to control a supply of electrical power to the device.

[0043] The device may further comprise a cut-out switch adapted to disconnect the electrical power from at least the heating element when one or more predetermined cut-out conditions are met.

[0044] The device may further comprise a cut-out temperature sensor located in close proximity to the control circuit and connected thereto. A cut-out condition may include a pre-determined threshold temperature being met by the cut-out temperature sensor. Thus, if the threshold temperature is reached the cut-out switch may disconnect the electrical power from at least the heating element if a cut-out condition is met, an indicium may be activated to alert a user.

[0045] The cut-out temperature sensor may thus override the control of supply of electrical power to the heating element. This is a safety feature to ensure that material in the heater does not reach dangerous temperatures, and furthermore to ensure that the control circuit and/or any other electrical or electronic components do not reach temperatures at which they may cease functioning temporarily or permanently. Yet further, the cut-out switch and/or cut-out temperature sensor as described may be adapted to function at temperatures well above the pre-determined threshold temperature, providing for a disconnection of the electrical power from the heating element even in a situation in which one or more components of the control circuit have failed due to an excessive temperature.

[0046] The programme switch may have a multiplicity of selectable states.

One or more selectable states may correspond to a pre-determined profile. The programme switch may comprise a multi-polar rotatable switch. Alternatively, the programme switch may be a push-button selector.

[0047] The control circuit may be located between the outer wall and inner wall of the housing. Such an arrangements provides an efficient use of available space. The housing may further comprise one or more open-ended ducts arranged between the outer wall and inner wall. Thus, air may flow through the said one or more ducts to provide a degree of cooling of the control circuit.

[0048] The housing may further comprise a stand located substantially below the base of the housing. In effect, such a stand raises the base of the housing away from a surface on which the device is placed. Such a stand may thus provide a degree of insulation to prevent such a surface from being damaged by heat from the base. Furthermore, such a stand may improve the effectiveness of the one or more ducts -in turn increasing cooling of the control circuit.

[0049] The stand may comprise a plurality of feet, spaced apart from one another. Such an arrangement may provide for air to flow between the feet into the said ducts.

Detailed description of the invention

[0050] Elements of the present inventive concept will now be described, with reference to Figure 1 which is an electronic circuit block diagram embodying certain elements described above.

[0051] Thus, in Figure 1 circuitry 10 comprises a mains power source 12 connected via a switch 14 to a transformer 18 via a thermal fuse 16. The transformer 18 acts as a power supply to the remainder of the circuitry 10, by providing power to a control circuit 20. Control circuit 20 comprises a microcontroller and optical isolator (not shown) and is connected to a display and keyboard module 22, a clock module 24 and a heater 26 via a triac 28. The control circuit 20 is further connected to a thermal sensor 30. The clock module 24 is further connected to a batter 32.

[0052] In use, the control circuit 20 controls the action of the heater 26 in accordance with preprogramed behaviours, commands entered from the display and keyboard module 22 and information received from the thermal sensor 30 and clock module 24. Much of the circuitry 10 can be isolated from the mains power source 12 by switch 14 and thermal fuse 16. Thus, a user may isolate the rest of the circuitry 10 manually, and there is additionally a safety thermal override provided by the thermal fuse 16.

Claims

CLAIMS1. A depilatory wax heater device having a housing comprising an outer wall, inner wall and a base at substantially a bottom of the inner wall, the base having at least an upper surface; wherein the inner wall of the housing and the upper surface of the base form a cavity within the device; the device further comprising a control circuit connected electrically to a heating element, a primary temperature sensor, a clock, a timer and a programme switch, wherein the control circuit is adapted to receive an electrical signal from each of the primary temperature sensor, clock, timer and programme switch and is adapted to control supply of electrical power to the heating element according to the said electrical signals and according to one or more pre-determined factors, wherein the predetermined factors comprise: maximum temperature; minimum temperature; preferred temperature; and maximum rate of temperature change.
2. A depilatory wax heater according to claim 1, further comprising a container removably disposable within the cavity, the container having a container base and container wall, and wherein the primary temperature sensor is located between the base of the housing and the base of the container.
3. A depilatory wax heater according to claim 2, wherein the container has a flanged portion at an end away from the container base.
4. A depilatory wax heater according to any preceding claim, further comprising a removable lid, wherein the device and/or the lid is provided with a resiliently deformable sealing element.
5. A depilatory wax heater according to any preceding claim, wherein the primary temperature sensor is an infrared radiation detector.
6. A depilatory wax heater according to claim 5, wherein the primary temperature sensor is a thermopile.
7. A depilatory wax heater according to any preceding claim, wherein more than one discretely-located temperature sensors are arranged in parallel to provide a temperature signal to the control circuit.
8. A depilatory wax heater according to any preceding claim, wherein the primary temperature sensor is arranged to measure the temperature of the container.
9. A depilatory wax heater according to claim 8, wherein the control circuit is adapted to recognise a variation in the rate of change of temperature of the container.
10. A depilatory wax heater according to any preceding claim wherein the control circuit is adapted to receive a temperature signal from the primary temperature sensor at regular intervals.
11. A depilatory wax heater according to claim 10, wherein the control circuit is adapted to receive a temperature signal from the primary temperature sensor at approximately 12 to 15 times per second.
12. A depilatory wax heater according to any preceding claim, wherein the control of electrical supply to the heating element is made according to one or more pre-determined profiles.
13. A depilatory wax heater according to claim 12, wherein the profile comprises a description of a preferred variation of temperature over a period of time.
14. A depilatory wax heater according claim 13, wherein the profile describes a change of temperature from an ambient or starting temperature to a preferred temperature over the course of a number of minutes.
15. A depilatory wax heater according to any of claims 12 to 14, wherein the profile describes a temperature path which increases initially to a temperature above a preferred temperature and then reduces subsequently so that the said 25 preferred temperature may be achieved.
16. A depilatory wax heater according to any of claims 12 to 15 wherein the control circuit is further adapted to provide one or more overrides in which predetermined factors may override a pre-determined profile.
17. A depilatory wax heater according to any of claims 12 to 16, wherein the predetermined-profile comprises a time profile, and wherein the control circuit is adapted to control supply of electrical power to the heating element to switch on or off the heating element when the clock indicates one or more pre-set time.18. A depilatory wax heater according to claim 17, wherein the clock keeps time of day, and day of week information, and wherein the time profile comprises switching on and switching off times for each day of the week.17. A depilatory wax heater according to any preceding claim, wherein the control circuit is be adapted to activate a visual and/or aural indicium when a certain condition is met.
18. A depilatory wax heater according to any preceding claim, wherein the heating element comprises a substantially annular band.
19. A depilatory wax heater according to any preceding claim, wherein the heating element is located at the lower end of the cavity,
20. A depilatory wax heater according to any preceding claim, wherein the heating element is a resistive device.
21. A depilatory wax heater according to any preceding claim, wherein the heating element and container form an electro-magnetic induction relationship.
22. A depilatory wax heater according to any preceding claim, wherein the device further comprises a master switch to control a supply of electrical power to the device.
23. A depilatory wax heater according to any preceding claim, wherein the device further comprises a cut-out switch adapted to disconnect the electrical 20 power from at least the heating element when one or more predetermined cutout conditions are met.
24. A depilatory wax heater according to any preceding claim, wherein the device further comprises a cut-out temperature sensor located in close proximity to the control circuit and connected thereto.