Method for operating a product for spray-dispensing a flowable cosmetic preparation

Abstract

The invention relates to a method for operating a product designed as a hand-held device (1) for spray-dispensing a flowable cosmetic preparation, comprising: - a receptacle (25) for a storage container (13) in which the cosmetic preparation is stored; - a pressure chamber (14) having a flow channel (24) extending between an inlet (15) and an outlet (16), wherein the flow channel (24) has an average flow cross-sectional area and a channel inner wall area, - a conveying device (12) for conveying the cosmetic preparation from the storage container (13) into the pressure chamber (14); - a heating device (23) for heating the preparation in the pressure chamber (14); - a valve device for opening and closing the inlet (15) and the outlet (16); - a control unit for actuating the valve device in order to be able to generate a plurality of spray pulses per unit of time, after both a heating power for the heating device (23) and a first closing time T2 of the pressure chamber, during which the outlet (16) and the inlet (15) are closed, have been defined by the control unit depending on the viscosity of the cosmetic preparation, wherein the first closing time T2 is shorter for a low-viscosity preparation, having a viscosity of less than 1000 mPas, than for a high-viscosity preparation, having a viscosity of more than 1000 mPas, and wherein the heating power is higher for the low-viscosity preparation than for the high-viscosity preparation.

Description

[0001] "Method for operating a product for spraying a flowable cosmetic preparation"

[0002] Description

[0003] The invention relates to a method for operating a product designed as a handheld device for spraying a flowable cosmetic preparation.

[0004] German patent DE 10 2007 030 155 A1 discloses a handheld device for the cosmetic treatment of hair. This device has a receptacle for a reservoir containing the cosmetic preparation. A gas from a small gas tank is added to the cosmetic preparation. The gas-enriched preparation is then sprayed onto the hair through a nozzle. With this handheld device, both the cosmetic preparation and the propellant gas must be kept on hand.

[0005] WO 2021 / 028542 A1 discloses a mobile spraying system comprising a pressure chamber with an inlet and an outlet. A pump within the spraying system serves to transfer a fluid from the reservoir into the pressure chamber, which forms a flow channel for the fluid between the inlet and outlet. A heating device acting on the pressure chamber transfers thermal energy to the flow channel between the inlet and outlet, as well as to the fluid within it. Thus, with both the inlet and outlet closed, the heating device increases the pressure and temperature within the pressure chamber and the flow channel, respectively. Since the temperature in the pressure chamber is above the boiling point of the fluid at ambient pressure, a portion of the fluid evaporates instantly when the outlet is opened. This creates a spray jet of vapor and small droplets at the outlet.Although the pressure chamber and heating device make the spray system complex to set up, it eliminates the need to store an additional propellant gas.

[0006] A control unit for the spray system operates a valve assembly comprising an inlet valve and an outlet valve. The inlet and outlet are periodically opened and closed, with the pressure chamber being filled when the inlet is open and fluid flowing out of the pressure chamber in the form of a spray jet when the outlet is open. This allows for the generation of multiple spray pulses per unit of time.

[0007] In cosmetic hair or skin treatments, it would be advantageous if the spray system could be used in the form of a handheld device similar to a conventional aerosol can. This would allow the spray system to replace the aerosol can without requiring the user to change their established treatment practices. The invention therefore aims to provide a method for operating a handheld device for dispensing a free-flowing cosmetic preparation, enabling efficient and simple cosmetic treatment of hair and / or skin.

[0008] The object underlying the invention, namely the provision of a method for operating a handheld device for spraying a cosmetic preparation for the treatment of hair and / or skin, is achieved by the combination of features of claim 1. Exemplary embodiments of the invention can be found in the dependent claims to claim 1.

[0009] The inventive method is based on the fact that the handheld device allows the user to operate it in the most user-friendly way possible while also enabling a particularly precise spray result. For the purposes of this invention, "user" can be understood to mean both private end consumers and professional cosmetic service providers, including beauticians and hairdressers.

[0010] The handheld device includes, among other things, a pressure chamber with a flow channel for cosmetic preparation running between an inlet and an outlet, the flow channel adhering to defined geometric design features. Specifically, the ratio of the channel's inner wall area AK to the mean cross-sectional area of ​​the flow channel Ast is in the range of 200–2000, preferably in the range of 500–1500, and particularly in the range of 700–1000.

[0011] The mean cross-sectional area of ​​the flow channel is to be set as the average of the individual cross-sectional areas if the flow cross-sectional area is not constant along the length of the flow channel and different cross-sectional areas result for different longitudinal sections of the flow channel. The mean value is calculated from the sum of the cross-sectional areas weighted by the length of the respective longitudinal section. For example, if the cross-sectional area of ​​a first longitudinal section (with a length of 200 mm) is 4 mm² 2 and the flow cross-sectional area of ​​a second longitudinal section (with a length of 300 mm) 3 mm 2 , so the average flow cross-section is 3.4 mm 2 (= (200 mm * 4 mm 2 + 300 mm * 3 mm 2) / (200 mm + 300 mm)). With a consistently constant flow cross-sectional area, the mean flow cross-sectional area corresponds to this constant flow cross-sectional area.

[0012] The flow channel design described above allows for the emission of only very small quantities of preparation per spray pulse, as desired. Furthermore, the relatively narrow and long flow channel makes it possible to quickly heat the preparation within it, enabling the generation of multiple spray pulses per second. This closely approximates the continuous spray pattern of a conventional aerosol can in practical application.

[0013] The flow channel can be formed, for example, by a spirally wound tube or a meandering tube assembly, such that the largest external dimension of the tube or tube assembly is significantly smaller than the length of the flow channel. Here, the length of the flow channel refers to the distance the liquid preparation must travel through the flow channel between the inlet and outlet. For example, if a constant circular flow cross-sectional area with a diameter of 2 mm is maintained along the length of the flow channel, and the flow channel length (distance traveled by the fluid through the flow channel) is 400 mm, then the ratio AK / ASI = 800. The corresponding calculation is: AK / ASI = (3.14 * 2 mm * 400 mm) / (3.14 * (1 mm) 2 ) = 800.

[0014] Due to the high AK / ASI ratio, the cosmetic preparation can absorb a significant amount of heat in a relatively short time. The small cross-sectional area of ​​the flow channel results in a high flow velocity even at low throughput rates, enabling a large heat transfer from the heat-emitting surface of the channel's inner wall to the preparation flowing through it. Consequently, several spray pulses per second can be delivered. Each spray pulse is preceded by a heating phase in which both the outlet and inlet are closed, and the pressure and temperature within the flow channel or pressure chamber increase.

[0015] The product, designed as a handheld device according to the invention, thus enables a virtually continuous spray jet composed of a multitude of spray pulses per second. The number of spray pulses per second is preferably greater than 5, 10, or 15, corresponding to a frequency greater than 5, 10, or 15 Hz, respectively. Therefore, the handheld device can be used similarly to a conventional aerosol can, for example, to apply hairspray. The user, such as a hairdresser or private individual, can move the handheld device along the hair with a familiar motion using one hand to apply a comparable amount of hair cosmetic preparation.Based on the parameter control according to the invention, 1 to 3.5 g of the pure (propellant-free) hair cosmetic preparation can be applied in 10 seconds, which, assuming a frequency of 10 Hz (10 spray pulses per second), corresponds to an output of 0.01 g to 0.035 g per spray pulse.

[0016] The mean cross-sectional area of ​​the flow channel can be less than 9 mm². 2 and preferably smaller than 5 mm 2 The length of the flow channel can be greater than 200 mm.

[0017] In a preferred embodiment, the device is designed so that the reservoir can be replaced. An empty reservoir can thus be replaced with a full one. It is also possible to supply the handheld device with a different cosmetic preparation by replacing the reservoir. In addition to the hair cosmetic preparations already mentioned above, including styling, conditioning, bleaching, and coloring preparations, the cosmetic preparation can also be a skin cosmetic preparation (including conditioning, deodorant, sunscreen, and decorative preparations).

[0018] Based on the inventive method, in a handheld spray dispenser of the generic type, the control unit determines both a heating power for the heating device and a first closing time T2 of the pressure chamber, in which the outlet and inlet are closed, depending on the viscosity of the cosmetic preparation. For a low-viscosity preparation with a viscosity of less than 1000 mPas, the first closing time T2 is shorter than for a high-viscosity preparation with a viscosity greater than 1000 mPas. The heating power is also higher for the low-viscosity preparation than for the high-viscosity preparation.

[0019] The value of 1000 mPas given here refers to a viscosity of the liquid preparation at 20°C. In this context, the viscosity is preferably determined at a temperature of 20°C according to Haake (e.g., Haake Viscotester 550, measuring device MV2).

[0020] The low-viscosity preparation flows through the flow channel at a higher velocity than the high-viscosity preparation due to lower flow losses. This results in intensive heat transfer within the flow channel in a correspondingly shorter time. Therefore, the heating power required for the low-viscosity preparation must be higher compared to heating the high-viscosity preparation. The high-viscosity preparation requires more time to flow through the channel, but absorbs less heat per unit of time. Consequently, the heating power can be reduced for the high-viscosity preparation.

[0021] In one embodiment, the inlet is open and the outlet is closed during a first opening time T1, with the first closing time T2 being 1 to 3 times longer than the first opening time T1 for low-viscosity preparations and 3 to 5 times longer for high-viscosity preparations. The first opening time T1, i.e., the time during which the pressure chamber is loaded, can take values ​​between 10 and 50 ms for both low-viscosity and high-viscosity preparations. For a low-viscosity preparation with a first opening time T1 of, for example, 25 ms, the first closing time T2, during which the temperature and pressure of the preparation increase, would take a value of 50 ms with a factor of 2.

[0022] In one embodiment, during a second opening time T3, the inlet is closed and the outlet is open. The second opening time T3, which corresponds to the time of the individual spray pulse, can be longer than the first opening time T1. The ratio of T3 to T1 can take values ​​from 1.0 to 1.5.

[0023] The second opening time T3 can be followed by a second closing time T4, during which the outlet and inlet are closed. The second closing time T4 can be less than 10 ms, preferably less than 5 ms. In one embodiment, the second closing time T4 is 1 ms. The second closing time T4 provides a sharp separation between the second opening time T3 (spray pulse) and the first opening time T1 of a subsequent cycle.

[0024] The sum of the first opening time T1, first closing time T2, second opening time T3, and second closing time T4, which describes the entire cycle time, can be less than 150 ms. With a total time of 100 ms, this results in 10 cycles or 10 spray pulses per second.

[0025] Preferably, the heating device is powered by electricity. The electrical power supplied to the heating device fundamentally determines the heating power applied to the pressure chamber or flow channel, and thus ultimately the temperature in the flow channel. Depending on the application, the temperature in the flow channel can therefore be adjusted as needed via the control unit by means of the electrical power supplied to the heating device. The level of electrical heating power, which is preferably constant over a cycle and over a sequence of several cycles and is not only applied during the heating phase or the initial closing time T2, depends on how well the electrical energy is converted into heating energy and how efficiently this heating energy can be transferred to the flow channel and thus to the preparation contained therein.Preferred values ​​for the electrical heating power of the heating device are 200 to 400 watts for treatment with a low-viscosity preparation and 100 to 200 watts for treatment with a high-viscosity preparation.

[0026] The handheld device according to the invention essentially comprises a conveying system for transporting the cosmetic preparation from the storage container into the pressure chamber. This conveying system is preferably designed as an electrically operated pump, the pumping capacity of which, and thus also the delivery capacity, can be controlled as required by the electrical voltage applied to the pump. For low-viscosity preparations, the pumping capacity of the conveying system can be higher than for high-viscosity preparations. In one embodiment, an electrical voltage of 5 to 7.5 V is set for low-viscosity preparations. For high-viscosity preparations, the electrical voltage can be 7.5 to 10 V.

[0027] For low-viscosity preparations, the temperature in the flow channel can be between 110 and 140°C, preferably between 110 and 130°C. The temperature in the flow channel should be significantly above the boiling point of the preparation at ambient pressure so that, when the outlet valve is opened, the heated and pressurized preparation at least partially evaporates and, together with the unevaporated portion, forms the spray jet in the form of small droplets. If the temperature is set too high, there is a risk that the droplets will be too small and could lead to inhalation toxicity. It should also be noted that the preparation may contain ingredients such as fragrance oils, etc., whose effectiveness can be impaired at excessively high temperatures.

[0028] For highly viscous preparations, the temperature in the flow channel can be 130 to 160°C, preferably 140 to 150°C. It has been shown that a higher temperature is necessary for highly viscous preparations to prevent the spray droplets from becoming too large. Excessively large droplets can be perceived as unpleasant or, in the worst case, can cause burns upon contact with the skin, as a large droplet contains a significant amount of heat.

[0029] The invention is explained in more detail with reference to an embodiment illustrated in the drawing. The single figure 1 schematically shows a product according to the invention, designed as a handheld device for spraying a free-flowing cosmetic preparation. The handheld device as a whole is designated by 1.

[0030] The handheld device 1 has a housing 10, which is indicated by a dashed line in Figure 1. The housing 10 has a handle 11 and is designed in such a way that the handheld device 1 can be easily guided by a human hand, similar to a hairdryer.

[0031] The housing 10 contains an electrically driven pump 12, which pumps a cosmetic preparation (for example, a liquid hairspray solution or a liquid hair care product) contained in a reservoir 12 into a pressure chamber 14. The pressure chamber 14 has an inlet 15 and an outlet 16, with a flow channel 24 running between the inlet 15 and outlet 16, through which the cosmetic preparation is guided. The inlet 15 can be closed by an inlet valve 17. The inlet valve 17 is designed as a solenoid valve with a movable core 18 and a coil 19. When a current flows through the coil 19, a magnetic field is generated, which moves the core 18 to the left in the illustration of Figure 1 to open the inlet 15. Thus, it is a solenoid valve that keeps the inlet 15 closed (normally closed) when no current is supplied.Figure 1 shows the inlet valve 15 in a closed position.

[0032] An outlet valve 20 for opening and closing the outlet 16 is also designed as a solenoid valve with a movable core 21 and coil 22. Figure 1 shows the outlet valve 20 in an open position, in which the outlet 16 is open. The inlet valve 17 and the outlet valve 20 are part of a valve assembly that allows the inlet 15 and outlet 16 of the pressure chamber 14, and thus also of the flow channel 24, to be opened and closed.

[0033] A heating device 23, acting directly on the pressure chamber 14, heats the preparation in the pressure chamber 14 or in the flow channel 24. The heating device 23 is adjacent to the flow channel 24, which, viewed in the direction of flow, is located between the inlet 15 and the outlet 16 of the pressure chamber 14. The flow channel 24 has several channel sections arranged one after the other. The cross-sectional area (Ast) of the flow channel 24 is generally quite small, while the length of the flow channel 24, i.e., the distance the preparation travels in the flow channel 24, is comparatively large. According to the invention, the ratio of the channel's inner wall area (AK) to the cross-sectional area (Ast) is in the range of 200–2000, preferably 500–1500, and particularly 700–1000.

[0034] Pump 12 has a receptacle 25 which allows the storage container 13 to be replaced by another storage container with a different preparation.

[0035] As explained above, Figure 1 shows the inlet valve 17 in a closed position and the exhaust valve 20 in an open position. A second opening time T3 can be assigned to this configuration, which will be discussed in more detail later.

[0036] With inlet 15 open and outlet 16 closed, the pressure chamber 14 is filled with the preparation by pumping it from the reservoir 13 into the pressure chamber 14 via pump 12. This period, during which the inlet is open and the outlet is closed, is referred to here as the first opening time T1. The first opening time T1 can be, for example, 10 to 50 ms. The first opening time T1 ends when the inlet valve 17 closes the inlet 15. A first closing time T2 then begins, during which the preparation in the pressure chamber 14 or the flow channel 24 is heated by the heating device 23, thereby increasing the pressure in the pressure chamber. A temperature is reached in the pressure chamber that is significantly higher than the boiling point of the preparation at ambient pressure. The opening of outlet 16 initiates the second opening time T3, which can be, for example, 50 ms.Since the pressure in the pressure chamber 14 drops abruptly when the outlet 16 is opened, at least some of the preparation contained therein evaporates. The vapor and the unevaporated portion of the preparation, in the form of small droplets, create a fine spray that exits the pressure chamber 14 through the outlet 16. It is important that the vapor and the unevaporated portion are in the correct ratio and that the size of the individual droplets is neither too small nor too large.

[0037] The second opening time T3 (for example, 20 ms) is followed by a second closing time T4, during which, as with the first closing time T2, the inlet 15 and the outlet 16 are closed. The closing time T4 can be only one millisecond (1 ms). The sum of the times T1 to T4 constitutes a total cycle time, with one spray pulse occurring at each of the second opening times T3. The total cycle can be repeated any number of times, resulting in a sequence of pulsed spray pulses. If the total cycle time is, for example, 100 ms, the handheld device 1 emits 10 spray pulses per second.

[0038] Depending on the viscosity of the preparation contained in the reservoir 13, a control unit (not shown) of the handheld device 1 uses stored data to determine the opening times T1, T3 and closing times T2, T4 of inlet valve 17 and outlet valve 20. The electrical heating power of the heating device 23 is also determined depending on the viscosity of the preparation. For a low-viscosity preparation, the control unit specifies opening times T1, T3 and closing times T2, T4 that differ from those for a high-viscosity preparation. This ensures that a spray jet of the desired quality is produced in each case, regardless of the preparation. Thus, the handheld device 1 according to the invention...The inventive method makes it possible to provide different cosmetic preparations for the treatment of hair and / or skin as a fine spray jet in the form of spray pulses with a comparatively high frequency.

[0039] Not shown in Figure 1 is an electrical source that supplies the conveying device 12, the valves 17 and 20, the heating device 23, and the control unit (not shown) with electrical energy. The electrical source can be a rechargeable battery, which, for example, can be housed in the handle 11 or another suitable location within the housing 10. Alternatively, it can also be an external source that is connected to the handheld device 1 via a cable at the handle 11 and thus provides its power supply.

[0040] Reference numeral list

[0041] I Handheld device

[0042] 10 cases

[0043] II Handle

[0044] 12 Pump

[0045] 13 stocks older

[0046] 14 Pressure chamber

[0047] 15 Admission

[0048] 16 Outlet

[0049] 17 Inlet valve

[0050] 18 core

[0051] 19 coil

[0052] 20 Exhaust valve

[0053] 21 core

[0054] 22 coil

[0055] 23 Heating device

[0056] 24 Flow channel

[0057] 25 recording

Claims

Patent claims 1. A method for operating a product designed as a handheld device (1) for spraying a free-flowing cosmetic preparation, wherein the handheld device (1) comprises: a receptacle (25) for a reservoir (13) in which the cosmetic preparation is stored; a pressure chamber (23) with a flow channel (24) extending between an inlet (15) and an outlet (16), wherein the flow channel (24) has a mean flow cross-sectional area and an inner wall area of ​​the channel; a conveying device (12) for conveying the cosmetic preparation from the reservoir (13) into the pressure chamber (14); a heating device (23) for heating the preparation in the pressure chamber (14); a valve device for opening and closing the inlet (15) and the outlet (16);A control unit for controlling the valve device in order to generate several spray pulses per unit of time, characterized in that, depending on the viscosity of the cosmetic preparation, a heating power for the heating device (23) and a first closing time T2 of the pressure chamber, in which the outlet (16) and the inlet (15) are closed, are determined, wherein, for a low-viscosity preparation having a viscosity of less than 1000 mPas, the first closing time T2 is shorter than for a high-viscosity preparation having a viscosity greater than 1000 mPas, and wherein, for the low-viscosity preparation, the heating power is greater than for the high-viscosity preparation.

2. Method according to claim 1, characterized in that at a first opening time T1 the inlet (15) is open and the outlet (16) is closed, wherein the first closing time T2 is greater than the first opening time T1 by a factor of 1 to 3 in the case of the low viscosity preparation and by a factor of 3 to 5 in the case of the high viscosity preparation.

3. Method according to claim 1 or 2, characterized in that at a second opening time T3 the inlet (15) is closed and the outlet (16) is open, wherein the second opening time T3 is greater than the first opening time T1.

4. Method according to claim 3, characterized in that the second opening time T3 is followed by a second closing time T4, during which the outlet (16) and the inlet (15) are closed.

5. Method according to claim 4, characterized in that the second closing time T4 is less than 10 ms, preferably less than 5 ms.

6. Method according to claim 4 or 5, characterized in that the sum of first opening time T1, first closing time T2, second opening time T3 and second closing time T4 is less than 150 ms.

7. Method according to one of claims 1 to 6, characterized in that the pumping capacity of the conveying device (12) is greater in the case of a low-viscosity preparation than in the case of a high-viscosity preparation.

8. Method according to one of claims 1 to 7, characterized in that for the low viscosity preparation the temperature in the flow channel (24) is 110 to 140°C, preferably 110 to 130°C.

9. Method according to one of claims 1 to 8, characterized in that the temperature in the flow channel (24) is 130 to 160°C, preferably 140 to 150°C, for the highly viscous preparation.

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