WO2007141656A1

WO2007141656A1 - Dispensing device, method to dispense a substance and use of a dispensing device

Info

Publication number: WO2007141656A1
Application number: PCT/IB2007/002175
Authority: WO
Inventors: Jozef A. F. Baeten
Original assignee: Pss Belgium Nv
Priority date: 2006-06-08
Filing date: 2007-06-08
Publication date: 2007-12-13
Also published as: EP2037970A1

Abstract

Device for dispensing at least one substance (11), the device (1) comprising at least one holder (9) which is configured to hold the substance (11) to be dispensed, and at least one acoustic transducer (3) configured to generate both heat and sound during operation, wherein the holder (9) and transducer (3) are arranged such, that heat, generated by the transducer (3) during use, can induce and/or enhance the release of the mentioned substance (11). The invention further relates to a method to dispense at least one substance and to the use of a transducer a heating device, in particular to induce or enhance the release of at least one substance. The dispensing device is capable of dispensing a substance substantially homogeneously to the surrounding environment, as well nearly as farther away with respect to the device.

Description

DISPENSING DEVICE, METHOD TO DISPENSE A SUBSTANCE AND USE OF A DISPENSING DEVICE

The invention relates to a device for dispensing at least one substance, the device comprising at least one holder, which is configured to hold the substance to be dispensed.

Such devices are known from practice. The known devices can be different devices such as plug-in diffusers, automatic perfuming, thermal conduction devices, etc. Some of these known devices, like for instance a plug-in diffuser or a thermal conduction device may use volatizable product, provided in for instance a solid tablet or in liquid form, that is inserted into the device. The volatizable product can be heated by a resistor and releases particles into the device surrounding. A disadvantage of these known devices is that they are based on passive diffusing of particles into the device surrounding. For example, a plug-in diffuser in operation is plugged in a socket. An air treatment product like for instance an insect repellent or an air refresher is arranged inside the plug in diffuser and can be heated by a resistor. Release and dispersion of the particles of the air treatment product is based on thermal conduction, which results in a slow spreading of the air mixture in the device surrounding.

Another disadvantage is that the concentration of the released particles of the air treatment product like for instance perfume, chemicals or other particles, is relatively high in the direct surrounding of the device, for instance resulting in a strong odour, which can be unpleasant for users of the device.

Furthermore, because the passive release of the particles, the spreading of the particles farther away from the device takes a long time and a relatively large amount of particles to be released. Another disadvantage is that some of these devices after inserting a new air treatment product, such as a new tablet or liquid container, disperse air comprising a relatively large concentration of the air treatment product first. After the product has been in the device for a certain period of time, the released concentration of air treatment product has decreased, thereby reducing the effectiveness of the dispensing device.

It is therefore an object of the invention to provide a dispensing device of the abovementioned type, wherein the disadvantages of the known devices are minimized. More particularly, it is an object of the invention to provide a dispensing device that is capable of dispensing a substance substantially homogeneously to the surrounding environment, as well nearby as farther away with respect to the device, for example such that the device can dispense a substantially equal concentration of said substance.

In order to achieve this object, the device comprises at least one holder which ^' is configured to hold the substance to be dispensed, and at least one acoustic transducer configured to generate both heat and sound during operation, wherein the holder and transducer are arranged such, that heat, generated by the transducer during use, can induce and/or enhance the release of the mentioned substance.

The invention is based on the insight ttiat an acoustic transducer normally transforms a relatively large part of electrical energy supplied to the transducer to operate the transducer, into heat. Approximately 95% of the input of electrical energy can be transformed into heat by the transducer, and only a remaining circa 5% is transformed into acoustical radiated energy. Due to this output, a transducer voice coil can reach a temperature of approximately 150°C (in the case that such a voice coil is present) which makes it efficient to use the transducer to heat the substance in the device.

For example, the sound can include different types of sound, for example acoustical pressure, or pressure waves, audible sound and/or inaudible sound (infrasound). In an embodiment, the device can comprise a housing holding or enclosing a volume of air, wherein the housing is provided with the transducer, such that the device can be brought into resonance by operating the transducer at a suitable resonance frequency, the resonance frequency being below 100 Hz and particularly below 50 Hz.

The mentioned device resonance is also known as the fundamental device resonance, or a first resonance or first series resonance.

For example, the transducer can be operable below the mentioned resonance frequency during use, to generate both heat and sound. Also, the transducer can be adapted to operate at a frequency lower than 50 Hz. Besides, the transducer can be configured to operate at a frequency between 10 Hz and the mentioned resonance frequency. For example, the mentioned sound, or acoustical pressure, can be sound in a frequency range between circa 10 Hz until a first or lowest acoustic resonance frequency of the device, particularly in the case the transducer has been provided in a housing. In a further embodiment, the sound can at least comprise infrasound, and particularly substantially ^• consists of infrasound, which is non-audible to the human hearing. For example, the sound at least does not include ultra-sound, or sound waves with a frequency above 20000 Hz.

According to a further elaboration of the invention, the substance holder and transducer are arranged such, that sound, generated by the transducer during use, can enhance the dispensing of substance released from the holder. The transducer can provide pressure variations, thereby enabling the substance to disperse in the device surrounding, and thereby resulting in a homogenously spreading of substance in the device surrounding.

According to a further aspect of the invention, the transducer is thermally connected or connectable with the substance holder. For example, such a thermal connection can include thermal radiation, thermal convection and/or thermal conduction. For example, the substance holder can be is mounted on the back side of a magnet system of the transducer. Also, for example, in an embodiment, the transducer and the substance holder can be integrated with each other, or be made in one part.

As mentioned before, in certain embodiments, about 95% of the electrical energy that is put in the transducer may be transformed into heat. For example, in operation, the windings of the voice coil of the transducer heat up, and so for example a transducer magnet system. In case of a thermal connection between the transducer magnet system and the substance holder, substance being held by the substance holder can be heated up. Preferably, the substance holder is of a thermally conductive material, for instance steel, or aluminium. For example, the transducer can thermally contact the substance holder, hereby heating substance provided the in said holder. Due to the heating, particles of the substance leave the product and disperse in the air, thereby generating a substance-air mixture. Furthermore, using the transducer for heating the substance holder results in a simple construction of the device, which is favourable in terms of production time and costs of the device.

As an example, in a non-limitative embodiment, during use, a transducer voice coil can heat up to temperatures around 150°C. A transducer flux guide, for example steel, that can be responsible for guiding the flux lines of a transducer magnet system, can heat up towards temperatures around 80-110°C on its outside (for example in case of application of classical small neodymium loudspeakertransducers). Also, in an embodiment, the operating temperature on the flux guide parts of the magnet system can be adjusted by tuning the volume of the flux guide material (for example steel) as well the radiating surface of the flux guide part. A thermal conductor, for example a thin metal or aluminium plate, can be part of the substance holder, and may be in direct mechanical contact with the magnet system, for example using thermal conductive pasta. For example, a surface of the thermal conductor can be heated up like other parts of the transducer magnet system, wherein the thermal conductor can be configured to hold a tablet with the substance to be heated and dispersed. For example, experiments have shown that a good thermal conductor can be made of aluminium, since it has been found that aluminium can be really fast in taking over the temperature of other parts of the magnet system.

Also, in an embodiment a heat conductive transducer housing can be thermally connected or connectable to said substance holder. For example, the substance holder can be arranged separate from a transducer housing, but can be situated such that the substance is heated by the transducer housing via a thermal connection during operation of the device.

According to another aspect of the invention, the device housing comprises a membrane provided in a housing wall, which membrane is part of the transducer. Such a membrane can generate relatively large pressure variations, for example longitudinal waves, to enable an air/product-mixture to leave the device. The mixture can be actively distributed into the device surrounding, thereby providing an efficient spread of the mixture in the room to be treated.

In an embodiment, the transducer can operate on an infrasound level, which is favourable because said frequencies are not audible for human hearing. Consequently, the device is very silent during operation. Furthermore, said frequencies have proven to disperse the air mixture efficiently into the device surrounding, thereby covering a substantially large area around the device with a minimum concentration of air mixture. Also, an infrasound- transducer can generate relatively large amounts of heat during operation, which can enhance the desired dispersion of the substance.

Preferably, the transducer may be a loudspeaker, thereby providing a simple structure of the device, which is favourable with respect to the manufacturing costs of the device.

According to a further elaboration of the invention, a substance releasing opening in a device housing can comprise an open cell structure. When using an open cell structure in a releasing opening in the device housing, the device housing comprising the loudspeaker can act as a substantially closed box with increased mechanical damping (friction). Therefore, the impedance in a preferable frequency range between 10 Hz and a first device resonance frequency can be kept as low as possible and the corresponding current through the voice coil, hence power dissipation inside the voice coil, may be as high as possible with respect to the drive voltage of transducer. Due the implementation of this mechanical resistance that could be realised in the transducer as well in the outlet, the mechanical Q-factor can become dominant,(or the back-EMF from the electrical Q-factor is decreasing). Consequently the impedance from 10Hz up till a resonance can stay very low and so the current through the voice coil high and the loudspeaker can heat the substance efficiently.

According to a further aspect of the invention, the transducer is controllable to adjust the sound frequency and/or the spectrum and/or the amplitude during operation. This can be very favourable when a large quantity of substance is needed in a short time period, for instance in a bathroom or in a kitchen right after cooking a meal. The transducer can be controlled to operate such that the transducer moves the membrane during a short period of time at a higher frequency ( for example close to the resonance frequency so that velocity as well excursion of the air show a big increase) than a dispersion frequency of substantially 20 Hz. A relatively large amount of mixture is released in the room that enables fast masking of smell in a room. After the first large amount of mixture is released, the transducer is controlled to change the frequency into a certain dispersion frequency again, thereby constantly providing air mixture with a lower concentration of volatizable product particles in the room to treat the air in said room over a longer time period.

According to another aspect of the invention, the substance holder is adapted to hold an insertable carrier comprising substance, for instance a volatile product. Such a holding element holds the insertable carrier on a desired location in the device, thereby providing a maximum heat transmission between the transducer and the substance holder in order to enable efficient release of particles from the volatizable product into the air inside the device housing. Consequently, in operation, the device is able to effectively create a mixture out of the available air and substance available in said carrier. According to a further elaboration, said substance comprises at least one of: a perfume or other odour, a medicine, a chemical and an insect repellent. Preferably, the substance is an oil based, a gel based, an alcohol based or a solid product receivable in a carrier. Commonly known air treatment products like nice smelling fragrances can be used to for instance refresh a bathroom, kitchen or living room. Also smell masking chemicals to mask, for instance cigarette smoke can be diffused, or insect repellent to provide an insect free area. Furthermore, medicinal mixtures may be dispersed into the device surrounding in hospitals to provide medicine to a patient. Chemicals can be dispersed in industrial surroundings for instance to treat air when it is contaminated or to provide a specific chemical mixture for instance to condition of disinfect rooms.

In further elaboration of the invention, the substance holder is adapted to hold a plurality of insertable carriers, which can be interchanged to alternatingly provide different mixtures. Thanks to such substance holder it is possible to easily switch between desired mixtures to be released in a device surrounding. For instance, different perfumes to be used for air refreshment can be provided according to different user's preferences.

The invention also relates to a method for dispensing at least one substance, wherein a dispensing device according to the invention is provided, wherein a mixture is generated by releasing a substance into a volume of air by heating said substance, wherein the heating is at least partly effected by the at least one acoustic transducer. Such a method provides similar advantages as described with the abovementioned dispensing device.

Furthermore, the invention relates to use of a transducer, particularly an electro-mechanical-acoustic transducer or loudspeaker, as a heating device, which also provides similar advantages as the dispensing device.

The invention will be further elucidated by means of exemplary embodiments with reference to the accompanying drawings in which:

Fig. 1 shows a schematic view of an embodiment of a dispensing device;

Figs. 2-6 depict simulation results concerning an embodiment.

In figure 1 a dispensing device 1 is shown. The device 1 comprises a housing 2 holding or enclosing a volume of air A. The housing 2 further comprises a substance holder 9 adapted to release particles P of the substance 11 into the volume of air A (illustrated by arrows R2) to generate a mixture with the air. The release can be, for example, release by evaporation, diffusion, convection and/or via other ways. The substance 11 can be a perfume, fragrance or other odour, a medicine, a chemical like an odour masking chemical, a disinfectant or an insect repellent, a product for treating air, and or combinations of these and/or other products. The substance 11 is receivable in a removable carrier 10 and can, for example, be gel based, oil based, alcohol based or provided in solid form. The housing 2 further comprises a releasing opening 12 that enables the mixture to be released into the device surrounding S.

Furthermore, the housing 2 comprises an acoustic transducer, in this embodiment a loudspeaker 3. The transducer can bring the device into resonance when being operated at a suitable frequency, for example a frequency below 100 Hz.

The loudspeaker 3 is provided in the device housing 2 and comprises a loudspeaker membrane 4. The membrane 4 is provided in a housing wall 2a, or at least extends in an opening of the housing wall 2a. The membrane is arranged movable subsequently into and out of said volume of air A, presented by arrow Rl . More specific, the loudspeaker includes a voice coil 8 that is connected to the membrane 4, and a magnet system 20 comprising a permanent magnet and suitable flux guides (known as such to the skilled person) . In the present embodiment, in the housing 2, a signal generator 5 is provided that is adapted to drive the loudspeaker 3 with a suitable electric driving signal. A control 13 is provided (schematically shown) that is able to control the signal generator 5 in order to control the frequency and/or amplitude of the loudspeaker 3, consequently to control the frequency and/or amplitude of the membrane movements. The signal generator 5 can be configured to provide the transducer 3 with and alternating driving signal having at least one or more frequency components below 50 Hz. Increasing a driving signal frequency and/or driving signal amplitude can result in a larger amount of mixture dispensed into the device surrounding S in a certain period of time, while a decreasing of the frequency and/or of the signal amplitude provides less mixture into said surrounding S in the same period of time. Before operating the loudspeaker 3, the substance carrier 10 can be inserted into a substance holder 9 (illustrated by arrow R3) provided in the device housing 2. During operation of the device 1, the loudspeaker 3 is preferably operated at a dispensing frequency that is lower than 50 Hz. Preferably, the dispensing frequency has a value in the range of 10 Hz to a frequency at which the device 1 resonates.

The loudspeaker 3 is driven by the signal generator 5 that provides a suitable AC signal, for example a sinusoidal or pulsating voltage. During the time period that the generator 5 is driving the loudspeaker 3, the current in the voice coil 8 is transformed into heat. For example, the loudspeaker can be a commonly known loudspeaker 3 which transforms approximately 95% of the energy input into heat.

Also, during use, the loudspeaker 3 transforms part of an energy input into a mechanical stroke of the voice coil 8. The current in the voice coil 8 that is situated in a permanent magnetic field of a permanent magnet system 20 of the transducer is transferred such, that the voice coil 8 moves in and out of the volume of air A, as indicated by arrow Rl, thus generating acoustic pressure in the air volume A. Due to the fact that the voice coil 8 is connected to the membrane 4, said membrane 4 will move in a similar way as the voice coil 8. The voice coil 8 is centred in an air gap during the movement with aid of two suspensions 6, 7.

The transducer 3 is thermally connected to the substance holder through the magnet system 20, and preferably by a suitable thermal connection 21. For example, the thermal connection 21 can comprise a thermally conductive material, for instance steel, aluminium and/or thermal conductive pasta. The substance holder 9 is preferably made of thermal conductive material, for instance steel, or aluminium.

In operation, the mentioned heat generated by the voice coil 8 can be transferred into the magnet system 20, which can heat the substance holder 9 (via the thermal connection 21), thus the earner 10 and thus the substance 11 that is provided in the carrier 10. By heating the substance 11 , particles P can be released that mix with the air in the housing 2 and generate a resulting air/product-mixture.

During use, the moving membrane 4 generates pressure variations in the volume of air A. Due to the pressure variations, which in fact may be longitudinal waves, the mentioned air/product-mixture passes through the releasing opening 12 out of the housing 2 into the device surrounding S. The mixture passes through an open cell structure 12a that is arranged in the releasing opening 12. The open cell structure 12a enables the mixture to leave the housing 2 but at the same time acts as a mechanical resistance used to optimise mechanical Q-factor (quality factor), and thus current as well power dissipation in the voice coil . This results in low impedance at a dispensing frequency in the range of 10 Hz up to the mentioned resonance frequency and so a relatively high current in the voice coil 8, and therefore high power dissipation in the voice coil 8 providing an efficient operation of the device 1.

The housing 2 with the transducer 3 can act as a quasi closed box, thereby providing an above- mentioned resonance frequency, which frequency preferably is higher than the mentioned dispensing frequency.

If in a room S, quick refreshment is desired, for instance when cooking or smoking smell is dominating, the transducer 3 can be operated at a start up frequency that is higher than 30 Hz and preferably lower than the mentioned resonance frequency and/or at a higher amplitude during a short time period in order to generate acoustic pressure (sound) to dispense a relatively large amount of substance into the room S. After that short period of time, the transducer 3 is controlled to adjust the frequency of membrane movement to a lower frequency, and/or at a lower amplitude. The control 13 can also control the signal generator 5 based on a predetermined time interval, a predetermined start time and a predetermined end time. Especially in case of medicine dispensing for instance in a hospital, or during sleep of a patient, it can be favourable to operate the device at certain times during certain time intervals.

Figures 2-6 depict computer simulation results concerning a device that can be suitable for use in small living rooms, a bed room or similar locations. The simulated device is similar to the embodiment shown in Fig. 1 and comprised a loudspeaker having a membrane with a surface area of 130cm² . The netto internal volume of the device was 2 litres. A relatively small substance releasing opening, having an area of 8cm², was applied. A voltage of 8V Rms was used, in a frequency range between 0-100 Hz.

Figure 2 depicts a resulting transducer impedance (Ohm) versus the frequency (Hz). Figure 3 depicts a resulting excursion opening (m) versus frequency. The excursion opening is the excursion or displacement of the air enclosed in the releasing opening. Figure 4 shows the velocity (m/s) of air through the releasing opening 12, versus frequency. The current (A) through the transducer coil versus frequency is shown in Fig. 5. Fig. 6 shows the power dissipation(Watt) in the transducer coil. As follows from the simulation results, a first device resonance is found at a transducer frequency just about 40 Hz (peak P in Fig. 2). Near this resonance, the air speed through the device's releasing opening is relatively high (see Fig. 4). At lower transducer frequencies (below the resonance peak), the air velocity drops. However, at lower transducer frequencies, the power dissipation increases (to almost 30 Watt in the present embodiment). A large part of the dissipated power can be used to heat up the substance to be dispersed.

Although illustrative embodiments of the present invention have been described in greater detail with reference to the accompanying drawings, it is to be understood that the invention is not limited to these embodiments. Various changes or modifications may be effected by one skilled in the art without departing from the scope or the spirit of the invention as defined in the claims.

For example, the housing of the dispensing device can be of different kinds of designs and shapes. The transducer does not have to be a loudspeaker, but can be a different kind of transducer that has the same kind of properties as described before. Also a dispensing device operated by a generator that is battery driven is possible according to the invention. A battery driven dispensing device can be very useful in situations that no electricity supply is available, for instance when camping in a tent or a mobile home, on a boat, in a car, in case of power failure and many other situations. Furthermore, the dispensing device can have different dimensions for example for use in a consumer environment than for use in an industrial environment. Accordingly, also the demand for a certain quantity of air per time period can vary in different fields of application, as well as the quantity of substance to be released per time period resulting in use of different sizes of transducers and volumes of air. Finally, the dispensing device, either electrically driven or battery driven, can be used as a handheld body and cloth-perfuming device or as a medical handheld inhaler. It is to be understood that in the present application, the term "comprising" does not exclude other elements or steps. Also, each of the terms "a" and "an" does not exclude a plurality. Any reference sign(s) in the claims shall not be construed as limiting the scope of the claims. Also, a single processor, controller or other unit may fulfill functions of several means recited in the claims.

Claims

CLAIMS:

1. Device for dispensing at least one substance, the device (1) comprising at least one holder (9) which is configured to hold the substance (11) to be dispensed, and at least one acoustic transducer (3) configured to generate both heat and sound during operation, wherein the holder (9) and transducer (3) are arranged such, that heat, generated by the transducer (3) during use, can induce and/or enhance the release of the mentioned substance (11).

2. Device according to claim 1, wherein the substance holder (9) and transducer (3) are arranged such that sound, generated by the transducer (3) during use, can enhance the dispensing of substance (11) released from the holder.

3. Device according to claim 1 or 2, wherein the mentioned sound is infrasound.

4. Device according to anyone of claims 1-3, wherein the transducer (3) is thermally connected or connectable to the substance holder (9).

5. Device according to anyone of claims 1-4, wherein the transducer (3) comprises a magnet system (20), wherein the substance holder (9) is thermally connected or connectable to the magnet system.

6. Device according to anyone of the preceding claims, wherein the substance holder (9) is a part of the transducer (3), or integrated therewith.

7. Device according to any of the preceding claims, wherein the device comprises a housing (2) holding or enclosing a volume of air, wherein the housing is provided with the transducer (3), such that the device can be brought into resonance by operating the transducer (3) at a suitable resonance frequency, the resonance frequency being below 100 Hz and particularly below 50 Hz.

8. Device according to claim 7, wherein the transducer (3) is operable below the mentioned resonance frequency during use, to generate both heat and sound.

9. Device according to claim 7 or 8, wherein the at least one substance holder (9) is arranged within the device housing, or can be moved to a position within the device housing.

10. Device according to claim 9, wherein the device housing comprises a substance releasing opening (12) to release substance (11) to an environment, wherein the releasing opening (12) preferably comprises an open cell structure.

11. Device according to anyone the preceding claims, wherein the transducer (3) is controllable to adjust the sound frequency and/or the spectrum and/or the transducer amplitude during operation.

12. Device according to anyone of the preceding claims, wherein the substance holder (9) is adapted to hold an insertable carrier comprising substance (11), for instance a volatile product.

13. Device according to anyone of the preceding claims, wherein the substance holder (9) is adapted to hold a plurality of insertable carriers, which can be interchanged to altematingly provide different mixtures.

14. Method for dispensing at least one substance, wherein a dispensing device according to anyone of the preceding claims is provided, wherein a mixture is generated by releasing a substance (11) into a volume of air by heating said substance, wherein the heating is at least partly effected by the at least one acoustic transducer (3).

15. Use of a transducer, particularly an electro-mechanical-acoustic transducer or loudspeaker, as a heating device.

16. Use according to claim 15, wherein heat, generated by the transducer (3), is used to induce and/or enhance the release of at least one substance (11).