Patent Application
20190216132
This application claims benefit under 35 USC X119 of German Application No. 10 2018 100 749.3 filed Jan. 15, 20185, the entire contents of which are incorporated herein by reference.
The invention generally relates to a porous sintered body for storing and/or vaporizing liquids. More particularly, the invention relates to a liquid storage and a vaporizer unit or vaporizer comprising a liquid storage and a heating unit for storage and controlled release of vaporizable substances. The vaporizer unit can be used in particular in electronic cigarettes, in medication administration devices, room humidifiers, and/or in heatable vaporizers for the release of substances into room air, such as fragrances or insect repellents, for example. It can also be employed in fog or haze machines.
Electronic cigarettes, also referred to as e-cigarettes below, are increasingly being used as an alternative to tobacco cigarettes. Typically, electronic cigarettes include a mouthpiece and a vaporizer unit as well as an electrical power source operatively connected to the vaporizer unit. The vaporizer unit includes a liquid storage which is connected to a heating element.
Certain medications, especially medications for treating the respiratory tract and/or oral and/or nasal mucosa, for pain therapy and psychotherapy and/or for the treatment of epilepsy as well as immunodeficiency syndromes are beneficially administered in the vaporized form, e.g. as an aerosol. The vaporizers of the invention can be used for the storage and administration of such medication, in particular in administration devices for such medication.
Thermally heatable vaporizers are increasingly utilized to provide an ambience with fragrant substances and/or with what is known as fog or haze. This may in particular be in bars, hotel lobbies, event locations and on stages, in training facilities, for example for fire protection, and/or in vehicle interiors, such as the interiors of motor vehicles, in particular automobiles. The vaporizer unit used in this case also has a liquid storage connected to a heating element. The liquid storage contains a liquid which is usually a carrier liquid such as propylene glycol and/or glycerol, in which additives are dissolved or more generally contained, such as fragrant and flavoring substances and/or nicotine and/or medications, with the use of appropriate solvents such as water and/or alcohols. The carrier liquid is bonded to the inner surface of the liquid storage by adsorption processes. Optionally, a separate liquid storage is provided to supply liquid to the liquid storage.
Generally, the liquid stored in the liquid storage is vaporized by heating the/a heating element, desorbs from the wetted surface of the liquid storage and can be inhaled by the user and/or is released into a space. Temperatures of over 200° C. may temporarily be reached in this context.
The liquid storage therefore has to exhibit high uptake capability and a high adsorption effect, however, at the same time the liquid has to be released rapidly at high temperatures.
From the prior art, liquid storages and vaporizer units are known which include a liquid storage made of porous glasses or ceramics. The higher temperature stability of such liquid storages allows to realize a more compact design of the vaporizer and thus of the electronic cigarette as a whole.
Local vaporization can be achieved in practice by a low pressure associated with a high temperature. In an electronic cigarette, the low pressure is achieved, for example, by the suction pressure when drawing on the cigarette during consumption, so it is the consumer who regulates the pressure. The temperatures required for vaporization in the liquid storage are produced by a heating unit. Usually, temperatures of more than 200° C. are reached here in order to ensure rapid vaporization.
DE 10 2015 113 124.2 describes open-pore sintered glasses as a liquid storage for electronic cigarettes. If provided with an electrically conductive layer, they can also be used as a heating element in a vaporizer head. The vaporization space is defined by the pores of the sintered body and is therefore limited. The limited vaporization volume also limits the maximum amount of vapor.
EP 2 764 783 A1 also describes liquid storages for electronic cigarettes comprising a porous sintered body. The latter is used together with a heating coil as a vaporizer.
Heating power is mostly provided by an electric heating coil powered by a disposable or rechargeable battery. The heating power required depends on the volume to be vaporized and on the efficiency of heating. In order to avoid decomposition of the liquid due to excessive temperatures, heat transfer from the heating coil to the liquid should occur through contactless radiation. For this purpose, the heating coil is mounted as close as possible to the vaporization surface, but preferably without touching it. If, however, the coil touches the surface, the liquid is often overheated and decomposes.
This is the case when a large amount of vapor is needed in operation and the liquid transport to the surface of the vaporizer does not occur fast enough. In this case, the energy supplied by the heating element cannot be consumed for vaporization, the surface dries out and might locally heat up to temperatures well above the vaporization temperature, and/or the temperature stability of the liquid storage is exceeded. Therefore, accurate temperature adjustment and/or control is essential. However, a drawback thereof is the resulting complex structure of the electronic cigarette, which manifests itself in high production costs, inter alia. In addition, vapor generation is possibly reduced due to the temperature control, and so is the maximum possible vapor intensity.
It is therefore an object of the invention to provide a porous sintered body for use as a liquid storage, which has a shape that is optimally adapted to the particular application and offers a variety of design options. Another object is to provide a vaporizer unit for hot applications, which comprises a liquid storage and a heating unit and exhibits improved efficiency over the prior art. In particular, the invention aims to provide a high amount of vapor generated with low heating power.
The liquid storage of the invention comprises a sintered glass or glass ceramic body, and the sintered body has an open porosity in a range from 10 to 90%. The liquid storage or the vaporizer unit may also comprise a sintered body in the form of a porous ceramic.
The liquid storage stores a carrier liquid by adsorptive interactions, and the carrier liquid may contain, for example, fragrant and flavoring substances and/or medications including active substances and/or nicotine dissolved in suitable liquids. If the liquid storage is used in a vaporizer device or is part of the vaporizer device, the stored liquid is vaporized, desorbs from the wetted surface of the vaporizer, and the vapor can be inhaled by the user.
Preferably, at least 90%, more particularly at least 95% of the total pore volume are open pores. Open porosity can be determined using measuring methods according to DIN EN ISO 1183 and DIN 66133.
According to one embodiment of the invention, the sintered body has an open porosity in a range from at least 20%, preferably 20% to 90%, more preferably 50% to 80%, and most preferably in a range from 60% to 80%. Due to the high porosity, high adsorption capacity of the sintered body is ensured. According to one embodiment, for example, the sintered body is able, at a temperature of 20° C. and within an adsorption time of 3 hours, to adsorb propylene glycol in an amount of at least 50% of its open pore volume. At the same time, the sintered body has a good mechanical stability. In particular sintered bodies with a relatively low porosity exhibit high mechanical stability, which can be particularly advantageous for some applications. According to another embodiment, open porosity is from 20% to 50%.
According to one embodiment of the invention, the pores have an average pore size in a range from 1 μm to 5000 μm. Preferably, the pore size of the open pores of the sintered body is in a range from 50 to 5000 μm, preferably in a range from 50 to 1000 μm, more preferably in the range from 100 to 800 μm and most preferably in a range from 200 to 600 μm. According to one embodiment of the invention, the pores have an average pore size of at least 50 μm.
Pores of such size are advantageous, as they are small enough to generate a sufficiently large capillary force to ensure resupply of the liquid to be vaporized, especially when used as a liquid storage in a vaporizer, at the same time they are large enough to allow for rapid release of the vapor.
The sintered body is a shaped body having at least two channels. According to one embodiment, the channels extend over the entire length l of the shaped body. Thus, the channels have the same length as the shaped body or as the dimension of the shaped body in the direction in parallel or at least substantially in parallel to the channels. Thus, the channels open to at least two end faces of the shaped body, i.e. the ends of the channels are open. Open channels are particularly advantageous if vapor shall escape therefrom, i.e. if they are vaporization channels.
Alternatively, at least one of the channels may have a channel length lc which is shorter than the length l of the shaped body. Depending on the arrangement of the respective channel or channels, the channel may have closed channel ends. Channels with one open end and one closed channel end are possible as well. Such channels in particular function as inflow channels for supplying the liquid to be vaporized. Liquid can thus flow into the sintered body through the open channel end. Due to the closed end of the channel, leakage of the liquid is prevented at the same time, and/or transfer of the liquid into the evaporation channels is prevented or at least minimized.
The channels increase the surface area of the sintered body, so that the liquid storage has a large contact area for uptaking the liquid. As a result, quick uptake of the liquid is possible. When the liquid storage is used in a vaporizer, the channels at the same time increase the surface area for exit of the vapor.
The channels are defined by the surrounding material of the sintered body. The channel can be completely enclosed by the material of the sintered body along its longitudinal axis. According to one embodiment, the channels are bores or slits within the sintered body.
Alternatively or additionally, the sintered body may also have channels which are only partially enclosed by the material of the sintered body. According to this embodiment, the channels may be formed in particular as grooves in one or more lateral or outer surfaces of the sintered body.
One embodiment of the invention contemplates that at least one channel is formed as a bore, preferably a circular or ellipsoidal bore, or as a slit. Depending on the application and design specifications for a vaporizer design, other geometrical shapes of holes, grooves and slits are conceivable, for example with a polygonal cross section, although these may possibly be more complex to produce.
The sintered body may have different shapes, depending on its use. The particular shape can already be determined by the shape of the green body prior to sintering. Due to the mechanical stability of the sintered body, mechanical processing following the sintering process is also possible, for example by grinding, cutting, or drilling operations.
The sintered body may be formed in one piece. Another embodiment contemplates that the sintered body is made up of at least two individual parts which can be connected to one another. Alternatively, it is also possible for the individual parts of the sintered body to be installed separately from each other, for example in a vaporizer, i.e. without being frictionally, positively, or cohesively connected to each other.
According to one embodiment of the invention, the sintered body is in the form of a cylinder having a length l. In this embodiment, the channels extend in parallel or substantially in parallel. One of the channels is defined by the inner circumferential surface of the cylinder. This channel will also be referred to as a first channel below. The liquid storage has at least one further, second channel in this case.
One embodiment contemplates that the liquid storage has at least two second channels, preferably at least three second channels, and more preferably at least four second channels. Preferably, the second channels are arranged symmetrically around a first channel.
According to one embodiment, the second channels have a closed circumferential surface which is defined by the material of the sintered body.
A further embodiment contemplates that the second channels do not have a closed circumferential surface defined by the material of the sintered body. Such second channels are thus located in the outer lateral surface of the hollow cylinder and have an opening along their longitudinal axis.
The sintered body of this embodiment preferably has a star-type or star-like shape. In this case, the number and shape of wings or points of the star is determined by the number and cross-sectional shape of the second channels. According to one embodiment, the sintered body has 2 to 20, preferably 4 to 10 star points or wings.
The second channels may have a circular or ellipsoidal cross section in this case. Alternatively, the second channels may have a triangular or substantially triangular cross section. Alternatively, the second channels may also have other polygonal shapes. Helical channels or channels in the form of annular cuts in the peripheral area of the hollow cylinder are also possible. Corners or edges of the wings or points of the star may be rounded or be not sharp, for constructive-, material- and/or manufacturing-related reasons.
The circumferential surface of the channel comprises two side surfaces of the sintered body in this case, which are defined by the wings or points of the star shape. In this case, the angle x between the center lines of the respective wings or points of the star is from 10 to 180°, preferably from 15 to 90°, more preferably from 30 to 60° and most preferably from 30 to 45°. According to one embodiment of the invention, the sectional area of the star points defined by the second channels decreases from inside outward.
In a preferred embodiment, the star-shaped sintered body has at least five, more preferably at least six, and most preferably at least eight second channels. The angle x is preferably 40° to 75° in this case.
The angle x is identical for all second channels of the sintered body. Thus, the second channels are arranged symmetrically. However, embodiments in which the second channels have different angles x and/or in which the perimeter is not completely covered by points or wings of equal or different angular spacing are also possible.
According to another embodiment, the sintered body has a cuboidal shape. In this case, the channels may be aligned parallel or perpendicular to the cuboid's edge having the greatest edge length.
For example, one embodiment contemplates a cuboid sintered body having channels that are aligned parallel or substantially parallel to the cuboid's edge with the greatest edge length. Such an arrangement allows to realize liquid storages with extra-long channels.
If, on the other hand, the channels are oriented perpendicular or substantially perpendicular to the cuboid's edge with the greatest edge length, then many channels with a comparatively short channel length can be obtained.
In this case, the channels may be formed as channels with closed lateral surface, i.e. the channels are located inside the cuboid sintered body. Vaporizers comprising a liquid storage of this embodiment can exhibit high vapor outputs, due to the long channels and the associated large vaporization surface area.
Alternatively or additionally, the sintered body may have open channels. In this case, a first channel may be arranged at an angle relative to a second channel, for example. In particular, the first and second channels may be arranged orthogonally to one another. The one or more second channels may be used to ventilate the sintered body. In this way, individual regions of the sintered body may be provided with air channels.
Another subject matter of the invention is a vaporizer unit for hot applications, which comprises a sintered body according to the invention as a liquid storage. The vaporizer is particularly suitable for use in an electronic cigarette, in medication administration devices, or in thermally heated fragrance vaporizers. The use for so-called fog machines which generate rather large amounts of vapor is possible as well. The vaporizer unit comprises a heating element. The heating element is preferably arranged directly on the surface of the sintered body.
The arrangement of the heating element directly on the sintered body is advantageous because the heating element mounted directly on the liquid storage requires less energy for vaporization. This saves battery power of the electronic cigarette. In addition, better temperature control can be achieved. Moreover, direct contact is also advantageous in terms of design options, for example in an electronic cigarette.
Furthermore, the sintered body may be shaped such that the vaporizer can be adapted to the geometric requirements of an electronic cigarette. Also, various design options are possible for the electronic cigarette in this way, which are no longer limited by the geometry of the vaporizer. For example, flat vaporizer are possible, for example in the form of a polygon or a disc.
Moreover, the electronic cigarette may have a more compact design, or the additional space available within the electronic cigarette may be used for other functions. Furthermore, the heating power can be influenced through the geometry and the dimensions of the heating element.
One embodiment contemplates for the heating element to be installed and/or applied in the form of a metal foil, a metal wire or, preferably, an electrically conductive coating. Due to the high temperature stability of the sintered body, it can be positioned very close to the heating element.
When an electrical voltage is applied, high temperatures are generated in the vaporizer by the electrically conductive coating, so that the carrier liquid is vaporized, desorbs from the wetted surface of the vaporizer, and the vapor can be inhaled by the user or is released into a space.
According to one embodiment of the invention, the heating element is in the form of an electrically conductive coating which is bonded to the surface of the sintered body, preferably by a material bond. Not only the pores on the lateral surfaces of the porous sintered body can be provided with the electrically conductive coating, but also the pores in the interior of the sintered body. Thus, the open pores throughout the volume of the sintered body are provided with the electrically conductive coating. Consequently, when a voltage is applied to the sintered body coated according to the invention, a current will flow through the entire volume of the sintered body which will therefore be heated throughout its volume. Hence, the electrically conductive coating is deposited on the surface area of the sintered body and bonded to the surface of the sintered body. The electrically conductive coating is thereby lining the pores which are located in the interior of the sintered body, so that when at least a portion or section of the sintered body is electrically contacted and powered, a current will flow at least partially through the interior of the sintered body and thereby heat the interior of the sintered body.
Thus, in this embodiment of the invention, heating is achieved throughout the entire current-carrying volume of the sintered body and accordingly the liquid to be vaporized is vaporized throughout the volume of the sintered body. Thus, the vapor is not only produced locally on the surfaces defining the lateral surfaces of the sintered body, but also inside the sintered body. The electrically conductive coating is applied on the surface area of the sintered body, at least partially and/or in sections thereof, and therefore forms at least part of the pore surface thereof.
In contrast to vaporizers which have a localized heating device such as a heating coil or an electrically conductive coating only on the lateral surfaces of the sintered body, capillary transport to the surface of the sintered body is not necessary. This prevents the vaporizer from running dry due to not enough capillary action and thus from local overheating. This has an advantageous effect on the service life of the vaporizer unit. Furthermore, in the event of local overheating of the vaporizer, decomposition processes of the liquid to be vaporized might be caused. This might be problematic, on the one hand because the content of active substance of a medication to be vaporized is reduced, for example. On the other hand, decomposition products are inhaled by the user, which may imply health risks. In the present vaporizer, by contrast, this risk does not exist.
The electrically conductive coating may in particular comprise or consist of a metal such as, for example, silver, gold, platinum, or chromium, or a metal oxide. In one embodiment of the invention, the metal oxide is a metal oxide selected from the group consisting of indium tin oxide (ITO), aluminum-doped zinc oxide (AZO), fluorine tin oxide (FTO), and antimony tin oxide (ATO). Metal oxides have proved to be particularly advantageous here, because of their good adhesion to glass and due to the good wetting behavior of the liquid to be vaporized on the metal oxide. Moreover, the aforementioned metal oxides, in particular ITO, exhibit high chemical and mechanical stability and are insoluble in water and alcohol, so that they are inert towards the solvent of the liquid to be vaporized. In addition, the metal oxides mentioned above are stable under temperatures of up to 2000° C. Preferably, the coating contains ITO and/or is an ITO coating.
According to one embodiment, the sintered body is in the form of a hollow cylinder of length l and has at least two channels. The channels extend parallel to the length l of the hollow cylinder or of the coated sintered body.
One embodiment contemplates that the coated sintered body is connected to a current and/or voltage source such that the current flows through the cylinder from one end face to the other end face. Hence, electrical connection is established on the end faces of the hollow cylinder and can be achieved by connecting two metallic contact plates, mechanically (frictionally) or by a solder connection or soldering of terminals (by a material bond), for example. In some cases, the establishing of electrical connection can be promoted or prepared by using electrically conductive pastes. For better bonds to the electrical terminals, it is also possible to apply a second electrically conductive layer to the areas of the sintered body to be electrically contacted, for example a conductive and/or solder layer or paste.
Since the two end faces lie parallel to each other, the current flows uniformly through the cylinder, so that uniform heating power is generated within the vaporizer.
The channels serve as a vaporization space in which the liquid exits from the circumferential surface of the channels and is vaporized. The amount of vapor that can be produced depends on the size of the circumferential surface and increases with increasing surface area.
Suction pressure and flow rate can be adjusted through the diameter of the channels and through the channel length. A high suction pressure can be achieved by small diameters and/or long channels. The volume flow increases accordingly with increasing diameter and decreasing channel length.
In the case of a hollow cylinder with only one centrally located channel, the wall thickness of the hollow cylinder determines the transport path of the liquid to be vaporized to the exit surface and thus also the efficiency of the vaporizer. With increasing wall thickness of the vaporizer, the transport path to the exit surface increases and the efficiency of the vaporizer decreases. This can be problematic especially in large vaporizers which have a correspondingly large wall thickness.
If large amounts of vapor and/or a high volume flow are required, it is usually possible in the case of a hollow cylinder that has one channel to increase the volume of the vaporizer and the vapor exit surface. However, increasing the circumferential surface of the channel, i.e. the inner surface of the hollow cylinder, results in a decrease of suction pressure. This may entail an unfavorable mix of little vapor with a lot of air in the interior of the hollow cylinder, which may have an adverse effect on a uniform release of the liquid to be vaporized.
An increase of the length of the vaporizer will also result in an increase of the amount of vapor, however, electrical resistance will increase as well due to such increase in length, so that electric power is reduced.
Therefore, an inventive vaporizer has at least two channels. According to one embodiment, the coated hollow cylinder has at least one first and at least one second channel, which have closed circumferential surfaces. Thus, the channels are located inside the sintered body and have openings at the end faces of the hollow cylinder. Preferably, the inner circumferential surface of the hollow cylinder is defined by the first channel. So, the first channel preferably defines the center of the hollow cylinder.
The second channels are preferably arranged symmetrically or at least substantially symmetrically with respect to the first channel. With the second channels, the vaporization surface area is increased compared to a respective cylinder that has only one channel, without need to increase the total diameter of the hollow cylinder. Accordingly, the transport path of the liquid remains short, so that the additional channels do not adversely affect the efficiency of the vaporizer. Rather, the additional channels reduce the transport path of the liquid from the outer lateral surface to the circumferential surface of the channel. This increases the amount of vapor that is released from the vaporizer and reduces energy consumption.
Furthermore, since the length of the cylinder does not have to be increased, the specific electrical power of the vaporizer remains the same. Suction pressure can be adjusted through the number of channels and the diameters of the channels.
Another embodiment contemplates a different mode of electrical contacting of the vaporizer. In this case, one electrical terminal or electrical contact, for example the positive terminal, is placed in the first channel, while the outer lateral surface of the cylinder then defines the other electrical terminal of the heating element, for example the negative terminal. In case of electrical contacting with the positive terminal inside the first channel, the current will flow from the center of the cylinder towards the outer surface thereof. Furthermore, the second channels function as exit areas for the vapor. According to one embodiment, the sintered body may additionally have a second electrically conductive layer, at least on portions of the surface, for improving electrical contacting.
If the negative terminal is disposed on the outer lateral surface, it is advantageous if the coated sintered body contacts the housing of the vaporizer since the housing is usually connected to the negative terminal of the power source or voltage source. Therefore, electrical insulation will not be necessary, in contrast to the case of electrical contacting at the end faces.
For electrical insulation, in particular in electronic cigarettes, an intermediate layer of electrically insulating material is used between the housing and the heating element, i.e. the coated vaporizer, for example nonwoven or fibrous materials such as cotton, glass wool, cellulose, or wool. However, such insulation is not stable in shape, so that the heating element might unintentionally contact the housing. This is especially the case when very large heating elements are used. If the cylinder is electrically contacted at the end faces, such heating element-to-housing contact will result in a short circuit.
The electrical contacting as described above with current flow of from the interior of the cylinder towards the outer lateral surface is therefore particularly suitable for vaporizers with large heating elements.
Another advantage of this electrical contacting is that the current flow within the heating element is independent of the length of the cylinder. Hence, the vaporization volume can be increased by increasing the length of the cylinder, without thereby increasing electrical resistivity. Thus, even with an increase in the length of the hollow body, the specific heating power will remain constant in the volume. This allows to provide very long vaporizers with small diameters and high vapor output.
In case of an electrical contacting as described above, the specific heating power is inversely proportional to the diameter of the vaporizer. Vaporizers with small diameters as used in electric cigarettes, for example, have a very high heating power in case of this electrical contacting. The heating power, in turn, may also be defined by the thickness of the electrically conductive coating and is proportional to the layer thickness. Hence, small vaporizers which shall have a heating power in a range from 8 to 80 W which is typical for electronic cigarettes, only need a comparatively thin electrically conductive coating. In particular when using expensive coating materials such as ITO, this is an economic advantage.
Another advantage of electrical contacting with one of the electrical terminals or electrical connections or contacts and in particular the positive terminal disposed in the first channel is that the current flow can be selectively directed within the coated sintered body. So, in contrast to electrical contacting end face to end face of the cylinder, it is furthermore possible to have inhomogeneous distributions of the current flow.
In this case, the current flow can be directed in particular in dependence of the position of the second channels and their cross-sectional shape. The current flow can also be spatially directed in dependence of the placement of the second electrical terminals, for example the negative terminals.
In case of a cylinder that has only one first channel and no further channels, and in which the negative terminal is formed by the entire outer lateral surface of the cylinder, the electrical currents from inside outward will be the same in all directions. Generally, the current and so the heating power as well decreases from inside outward in the vaporizer. However, an inverse power distribution, i.e. an increase in heating power from inside outward is more advantageous for vaporization. This is due to the fact that more liquid is supplied in the outer regions and so more power is required for vaporization in the outer regions.
This can be achieved, for example, by placing the negative terminal only in regions of the outer lateral surface of the cylinder which are located at a small distance from a second channel. As a result thereof, the current flow and thus also the heating power will be maximal in the regions of the sintered body around the second channels.
Concentrating the heating power in the regions around the second channels is advantageous because more heating power is required there due to the high vaporization. The remaining areas of the coated sintered body will have a lower temperature in this case.
In addition to the location of the negative terminal, the cross-sectional shape of the second channels also has an influence on current distribution in the coated sintered body. For example, channels with an elongated or ellipsoidal cross section aligned in the direction of the negative terminal will also result in a concentration of current flow in the regions of the sintered body adjacent to the second channels.
One embodiment contemplates that the second channels are only partially enclosed by the material of the sintered body. Thus, the second channels do not have a closed circumferential surface but are open on at least one side. Preferably, in this case, the second channels have a cross-sectional shape tapering towards the center of the cylinder. So, in this embodiment the second channels widen towards the outer surfaces of the sintered body.
In terms of current flow distribution in the sintered body it has been found particularly advantageous to have second channels of V-shaped or substantially V-shaped cross section. V-shaped cross section may also be understood as meaning a triangular or substantially triangular cross section in this case. The two sides of the open channel are defined by the material of the sintered body. The angle x enclosed by the center lines of the respective two star points or wings is preferably less than 45°.
According to one embodiment of the invention, the angle x is in a range between 30° and 60°.
Depending on their number, their location, and their cross section, the sintered body may thus have a star-shaped or partially star-shaped cross-sectional shape. A respective wing or point of the star shape is defined by two second channels. Sintered bodies with at least 4, preferably at least 6, and most preferably at least 8 second channels have proved to be particularly advantageous here.
In one embodiment of the invention, the cross section of the second channels is selected such that the sectional area of the star point decreases with increasing distance from the first channel.
In case of star-shaped heating elements it has been found to be particularly advantageous in terms of the spatial distribution of the heating power within the heating element to place one electrical terminal, for example the positive terminal, in the central first channel. The other electrical terminal is alternately positioned over every second of the second channels in this embodiment, so that the respective second channels are spatially closed by the other terminal. The channel thus has a closed circumferential surface. Preferably, the positive terminal is placed in the first channel. In this exemplary embodiment, part of the lateral surface of the respective channel is defined by the material of the coated sintered body, and part thereof by the material of the negative terminal. The so formed closed second channels are therefore spatially separated from the liquid in the liquid container and serve as vaporization chambers. The open second channels provide a large contact surface of the sintered body to the liquid. Thus, this embodiment provides for a rapid uptake of the liquid by the coated sintered body and for a rapid release through the large vapor exit surface, so that such vaporizers have a high efficiency. Furthermore, due to the specific placement of the electrical terminals, heating power is concentrated in the points or wings of the star shape. This is advantageous since in this way the heating power is greatest in the vicinity of the vaporization chambers.
One embodiment of the invention contemplates that the vaporizer has at least one third channel. The third channel extends transversely across the sintered body, preferably perpendicular relative to at least a first channel, and preferably it has a smaller diameter or a smaller cross-sectional area than the first channel and the second channel. The third channel in particular serves as an inlet opening for the fluid into the liquid storage. The third channel may in particular have a slit-like or circular shape. The third channel improves the uptake and transfer of the liquid into the vaporizer. In this case, the third channel is preferably not in communication with the first and second channels and is closed towards the vaporization space.
According to one embodiment of the invention, the vaporizer may have a plurality of heating zones which are defined by different terminals. These terminals may be separately connected electrically, so that the heating zones can be controlled individually. For example, the individual heating zones can be operated at different heating powers. If the heating zones are disposed at different positions of the outer lateral surface of a vaporizer in the form of a cylinder, for example, it is possible to achieve a temperature gradient in the vaporizer in this way. It is also possible to selectively connect or disconnect individual heating zones for controlling purposes, i.e. for increasing or reducing the heating power and hence the amount of vapor or dosage of active substances.
According to another embodiment of the invention, the coated sintered body has a cuboid or at least substantially cuboid or a polygonal cross section. The cuboid has edges a, b, and c, and the channels extend parallel to the edge a. The channels have a closed circumferential surface which is defined by the material of the coated sintered body. So, these are closed channels. The channels may be aligned parallel or perpendicular to the edge of the cuboid, which has the largest edge length.
For example, one embodiment contemplates a cuboid coated sintered body including channels that are aligned parallel or substantially parallel to the edge of the cuboid with the largest edge length. With this arrangement, liquid storages with extra-long channels are feasible.
If, on the other hand, the channels are aligned perpendicular or substantially perpendicular to the edge of the cuboid having the largest edge length, then many channels with a comparatively short channel length can be obtained.
In this case, the channels may be in the form of channels having a closed circumferential surface, i.e. the channels are located inside the cuboid vaporizer. Vaporizers with a liquid storage of this embodiment may have a high vapor output performance due to the long channels and therefore large vaporization surface area.
Alternatively or additionally, the coated sintered body may have open channels. In this case, a first channel may be arranged at an angle relative to a second channel, for example. In particular, the first and second channels may be arranged orthogonal to each other. In this way, individual regions of the sintered body may be provided with air channels.
Electrical contacting may be established via two opposite faces of the cuboid, which extend parallel to the channels. So, the faces serve as a positive or negative terminal.
Alternatively, two opposite faces of the cuboid serve as a negative terminal. In this embodiment, the positive terminal is located inside the sintered body. The channels serve as vaporization chambers and are preferably arranged equidistant from the first channel.
Another embodiment contemplates a coated sintered body including channels that have a closed circumferential surface, which circumferential surface is defined by the material of the coated sintered body. The terminal contacts are disposed such that when a voltage is applied the current flow in the sintered body will be locally limited to those regions of the sintered body which include the channels. This is advantageous, since in this manner the heating power is concentrated in the regions in which vaporization takes place, while the remaining regions of the sintered body are at a lower temperature. With an arrangement of the terminals on or in the sintered body it is thus possible to create zones within the sintered body, which exhibit a high heating power and so are at a higher temperature, so that it is there where vaporization preferably takes place. This includes preferably the channels of the sintered body, which present a large surface area for exit of the vapor. Other regions of the sintered body are not heated, or only weakly or less. They serve as storage regions. In this way, the liquid storage and the vaporizer can be implemented in a single materially bonded sintered body. In addition to a compact design, such vaporizer combinations are moreover leak-proof.
The channels may be arranged around a vaporization region. In a preferred embodiment, the sintered body has at least four channels. The channels are arranged in the sintered body in at least two rows, and the terminal contacts are placed such that the current flows through the regions of the sintered body around the channels and such that there is no or only a weak current flowing in the region between the rows of channels, and evaporation takes place only in the current-carrying regions of the sintered body. Alternatively, the channels may be arranged in a ring around the vaporization region. One embodiment of the invention contemplates a sintered body which has only the regions around the channels provided with an electrically conductive coating. Thus, only the coated region is electrically conductive and heatable, while the remaining regions of the sintered body serve as a storage region.
The invention will now be explained in more detail by way of exemplary embodiments and with reference to the figures, wherein:
Thus, channel 9b constitutes a vaporization zone. With that arrangement of the electrical terminals in combination with the cross-sectional shape of the second channels 9a it is possible to concentrate the heating power in the wings 70a of the vaporizer.
Channels 9a have an open V-shaped contour and thus provide for a large contact surface area to the liquid 12. Thus, the vaporizers shown in
In the vaporizer shown in
The cuboid vaporizer 1 of the invention can be adapted to the design in terms of shape and size such that it fits exactly in the position of standard wick and thus can replace the previously used wicks with heating coil by simple replacement of the components. In e-cigarettes and in vaporization chambers, the vaporizer 1 is installed such that the lateral surfaces of the vaporizer contact the wool layer (with liquid) 13 and uptake liquid 12 from the wool thereby. Liquid 12 is transported to the center, where it is heated and vaporized when the e-cigarette is switched on.
The contacting with contacts, or +/−terminals, is shown in
The region of the sintered body 7, which is close to the liquid container when used in a vaporizer, has no channels. Therefore, this portion of the sintered body is more solid. This is advantageous, since in this way the sintered body can fulfill a sealing function and can prevent leakage of the liquid. In addition, this region exhibits good thermal insulation, due to the solid construction. Due to its larger cross section, the electric current is distributed and the heating power is accordingly reduced in this region.
The vaporizers shown in
In the following optimizations, electrical currents are controlled through the placement of the terminal contacts. Although all areas have the same coating, electrical currents will only flow in the vaporization region. The storage region remains cold. Liquid will not be vaporized there and can be buffered there. Hence, liquid storage and vaporization can be achieved in a single porous body. The two regions can be partially separated by vapor exit channels 8.
Negative terminals 140, 141, and 142 can be powered separately from each other. Thus, it is possible during operation to initially apply power to only one negative terminal, for example. Accordingly, the respective adjacent region of the sintered body is then heated. If, for example, a higher heating power is required during operation, the additional negative terminals can also be powered.
Alternatively, it is also possible to power all the negative terminals 140, 141, and 142, and to apply different voltages. In this manner, different heating powers can be generated at the individual negative terminals 140, 141, 142. This can be exploited to generate a gradient in the heating power within the vaporizer, for example.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2018 100 749.3 | Jan 2018 | DE | national |
