EP3247234B1

EP3247234B1 - Electronic delivery unit and cartridge, an e-cigarette comprising the unit and cartridge, and method for delivering a delivery fluid

Info

Publication number: EP3247234B1
Application number: EP16710020.5A
Authority: EP
Inventors: Ray STORY; Gerhard Hendrik MULDER; Sybrandus Jacobus METZ; Johannes Kuipers; Hans Hendrik Wolters
Original assignee: Utvg Global Ip BV
Current assignee: Utvg Global Ip BV
Priority date: 2015-01-22
Filing date: 2016-01-18
Publication date: 2021-09-08
Anticipated expiration: 2036-01-18
Also published as: CN107427084A; EP3247234A1

Description

The present invention relates to a personal electronic delivery unit capable of receiving a cartridge with a delivery fluid. Such unit with a cartridge includes so-called E-cigarettes.
Delivery systems, such as E-cigarettes, are known and comprise an inhaling device with an inlet and an outlet that is shaped as a mouth piece. E-cigarettes further comprise a battery and a heater that is provided with energy from the battery. The heater is winded around a so-called wicking material that acts as a buffer, wherein the heater is switched on and off with a flow detector located in the inlet, for example. A buffer comprises the delivery fluid, such as a so-called E-liquid, usually being a mixture of propylene glycol, glycerine, nicotine, and flavourings. The heater vaporises and/or atomises the E-liquid to enable inhaling of the liquid.
Conventional E-cigarettes often comprise a first part with a battery and an air inlet, and a second part with the E-liquid and a heater element for atomizing and/or vaporizing the E-liquid. This second part is often disposable, such that a user is required to provide a new second part after having used substantially all the E-liquid.
EP 2 810 570 A1 discloses a personal delivery with a primary housing, a fluid path and a heater element.
Document WO 2016/108694 A1 (published on 07 July 2016 ) discloses a personal electronic delivery system with a heater comprising a metal conductor that is provided with a porous ceramic layer. The porous ceramic layer is configured to control the atomizing and/or vaporization. A buffer substantially surrounds the heater, wherein the buffer is provided with openings configured for transferring delivery fluid to the heater. The ceramic layer is provided on or at the conductor with plasma electrolytic oxidation.
The present invention has for its object to provide a personal electronic delivery unit, specifically capable of receiving a cartridge and to be used as personal electronic delivery system, including E-cigarettes, that provides a more efficient unit.
This object is achieved with the personal electronic delivery unit according to claim 1.
Providing a fluid path from the inlet towards the outlet, preferably embodied as a mouth piece, of the secondary housing enables inhaling at the outlet to draw/suck in ambient air, for example. When the primary housing is provided with a secondary housing comprising a cartridge with the E-liquid as a delivery liquid, there is provided a personal electronic delivery system, such as an E-cigarette that also include so-called E-cigars.
The heater or heater element that is included in and/or attached to the primary housing of the unit atomises and/or vaporizes the delivery fluid when the heater is switched on. Switching on the heater can be achieved with the use of a flow controller close to the inlet, for example. Energy is provided to the heater, by an energy source, for example a (rechargeable) battery. The delivery fluid can relate to a mixture of liquids and/or solids, including so-called E-liquids that may comprise a mixture of propylene glycol, glycerine, nicotine and flavourings. It will be understood that other ingredients can also be applied and/or nicotine can be omitted from the mixture. The delivery fluid is contained in a cartridge that can be refilled or is disposable. The cartridge is optionally integrated in the secondary housing and can be refilled or be disposes as a unit.
According to the invention the heater element is provided in the primary housing of the unit. Therefore, the heater element is not provided in a disposable cartridge. This obviates the need for providing a heater element in every (disposable) cartridge and enable re-use of the heater element with a further (disposable) cartridge. This contributes to a more sustainable unit.
By providing the heater element together with the energy source, such as a battery, preferably a rechargeable battery, in the primary housing a robust connection and energy supply can be achieved. This prevents malfunctioning of the unit due to an incorrect connection of the different parts of the system, such as an E-cigarette. Such malfunction due to non-optimal coupling of circuit parts is a problem in conventional systems.
A further advantage of providing the heater element in the primary housing instead of in a secondary housing with the cartridge is that the production process of the cartridges can be performed more efficiently. In fact, filling the cartridges with delivery fluid can be performed much faster when the heater element is provided in the primary housing. This renders the overall production process more efficient.
The heater element according to the invention preferably comprises a conductor that can be shaped as a plate, wire, foil, tube, foam, rod or any other suitable shape, preferably of a so-called resistance heating material that can be heated by applying an electric current to the conductor of the heater element. The conductor can be of a suitable material, including aluminium, FeAl, NiC, FeCrAl (Kanthal), titanium, and their alloys. Especially the use of the metal titanium provides good results.
In one of the presently preferred embodiments according to the present invention, the heater comprises a spiralled metal wire as the conductor with the wire being provided with the ceramic layer. Providing the heater with a spiralled metal wire an effective atomisation and/or vaporisation of delivery fluid can be achieved. The spiralled metal wire is preferably provided in the fluid path. This achieves an effective heating of the E-fluid.
Alternative configurations for the heater in a wire configuration include a straight wire, single or multiple layer solenoid wire, toroid single or multiple layer, and flat coil. Alternative configurations for the heater in a foil or plate configuration include a flat, round, rectangular shape, spiral wound, and folded configuration. Further alternative configuration for the heater in a tube configuration include a metallic tube with coated porous ceramic layer and optionally provided with a (static) mixing structure or helix structure, tube shape of foil/plate, and spiral wound foil/plate. An even further alternative configuration of the heater in a foam configuration includes a sponge structure.
In a spiralled embodiment of the heater element the central axis, or longitudinal direction of the spiralled metal wire, is positioned substantially transversally to the main fluid flow direction in the fluid path. In a presently preferred embodiment according to the invention the spiralled heater element has a central axis that is provided substantially transversely to the fluid path. Even more preferably, the fluid path is designed such that the inhaled fluid passes through the spiralled wire in a direction transverse to the central axis of the heater element. This enhances the atomisation and/or vaporisation of the delivery fluid, thereby improving control of these processes and/or reducing the amount of the required energy to perform these processes. This improves the lifetime of the unit according to the invention. Optionally, air guides are provided in the primary housing to direct the air in a substantially transverse direction towards the heater element.
In a presently preferred embodiment the heater element comprises a conductor and a porous ceramic layer that is configured to control the atomizing and/or vaporization.
The ceramic layer that is provided on or adjacent the conductor enables effective control of heater temperature, thereby preventing burning of components in the delivery fluid and/or other elements of the system, such as buffer material. This improves the quality of the inhaled fluid by preventing undesirable components being present therein.
It may seem counterintuitive to use a ceramic for the heater, as ceramics are known to be thermal insulators, or at least poor thermal conductors. Surprisingly however, the ceramic layer does have a positive effect on the heating of the delivery fluid. The inventors found that the ceramic layer is able to even out spikes in the temperature of the conductor, thereby preventing burning of the delivery fluid. Importantly, the pores of the ceramic layer allow the delivery fluid to come close to the electrical conductor, i.e. the pores can be said to reduce the effective thickness of the layer from a thermal point of view. Therefore, the pores mitigate the negative effect on the heat transfer of the normally poorly conducting ceramic. Moreover, the pores increase the contact surface between the ceramic and the delivery fluid, thereby further enhancing the heat transfer from the heater to the fluid. Therefore, the porous ceramic layer achieves an effective heating of the delivery fluid for vaporizing and/or atomising thereof, even though the ceramic material in itself is a poor thermal conductor.
As a further effect the ceramic layer provides structure and stability to the conductor thereby increasing the strength and stability of the heater as a whole. This is especially relevant in case the system is applied as an E-cigarette. Such E-cigarette is subjected to many movements, vibrations and/or other impacts. For example, the increased stability prevents malfunctioning and/or prevents contact of the heater with other components of the system, including buffer material such as a cloth that is drenched in delivery fluid such as E-liquid. This prevents undesired burning of components. Furthermore, the ceramic layer prevents the release of heavy metals.
Providing the heater element with a conductor and a ceramic layer enhances the possibilities for re-use of the heater element for further (disposable) cartridges. It was shown that such heater element was less sensitive to fouling as compared to convention heater elements, for example.
Also, the ceramic layer enables adsorption and/or absorption of the delivery fluid, such as the E-liquid, in the pores of the ceramic layer. This enables an effective transfer of energy from the conductor to the delivery fluid, including the E-liquid.
In a presently preferred embodiment according to the invention the ceramic layer has a thickness in the range of 5-300 µm, preferably 10-200 µm, more preferably 15-150 µm and most preferably a thickness is about 100 µm.
By providing the ceramic layer with a sufficient thickness the stability and strength of the heater is improved. Furthermore, the insulation is increased, enabling control of heat transfer and/or heat production. The thickness of the ceramic layer can be adapted to the type of E-liquid and/or the specific system and/or the desired characteristics. This flexibility during production provides a further advantage of the system according to the invention. According to claim 1, the ceramic layer is provided on or at the conductor with plasma electrolytic oxidation. The heater element is preferably made from a titanium material and/or another suitable material, on which a porous metal oxide layer, such as titanium oxide, is grown with plasma electrolytic oxidation. Plasma electrolytic oxidation enables that a relatively thick titanium oxide layer is grown from the titanium (>130 µm) by oxidizing (part of) the titanium to titanium oxide. Especially the use of titanium provides good results. The resulting layer is a porous, flexible and elastic titanium oxide ceramic. Plasma electrolytic oxidation (>350 - 550 V) requires much higher voltage compared to standard anodizing (15-21 V). At this high voltage, micro discharge arcs appear on the surface of the titanium, or other material, and cause the growth of the thick (titanium) oxide layer. Other metals, such as aluminium or nichrome, may also be used for the heater element of the system according to the present invention. For example, results have shown that a ceramic layer can be achieved on an aluminium foil of about 13 µm thickness, resulting in a flexible and elastic ceramic layer. One of the advantageous effects of using plasma electrolytic oxidation to provide the ceramic layer is that due of the growth of the layer from the metal during oxidation the adherence of the ceramic layer to the metal is excellent.
In a presently preferred embodiment the structure of the heating element comprises a thin wire of titanium, aluminium, or any other valve metal, such as magnesium, zirconium, zinc, niobium, vanadium, hafnium, tantalum, molybdenum, tungsten, antimony, bismuth, or an alloy of one or more of the preceding metals. Such valve metal is capable of forming an oxide layer which forms a protective layer on its surface and then stops it to oxidize further. In a presently preferred embodiment titanium is used for the heating element considering its relatively high resistance achieving a relatively fast heating process. The wire is coated on the other side through plasma electrolytic oxidation. Plasma electrolytic oxidation is done by placing the titanium wire in an electrolyte. For example, the electrolyte comprises 15 g/l (NaPO₃)₆ and 8 g/l Na₂SiO₃.5H₂O. The electrolyte is maintained at a temperature of 25°C through cooling. The wire is used as an anode and placed in a container containing the electrolyte. Around the wire a stainless steel cathode is positioned. A current density is maintained between the wire and cathode of about 0.15 A/cm². The current is applied in a pulsed mode of about 1000 Hz. The potential increases rapidly to about 500 Volt between the wire and the cathode. This creates a plasma electrolytic oxidation process on the anode wire and creates a ceramic layer. As the wire is small sized (100 micron) it has a relative high electrical resistance 61 Ohm/m. By applying a current to the wire during use of the personal electronic delivery system, the wire heats up. It will be understood that process parameters may depend on the structure of the heating element and/or the dimensions thereof.
In an alternative embodiment a plate of metal, for example aluminium, titanium or other valve metal, is coated on at least one side with a ceramic layer using plasma electrolytic oxidation, for example. Due to metal plate resistance its temperature increases when a current is applied. Also, a structure can be etched into the metal providing metal strips of metal having a relatively high resistance. The etching can be performed using electrochemical machining, for example.
Alternative manufacturing methods for the heater element include sintering or spark plasma sintering, oxidation of the surface layer of the metal by heating in oxygen rich environment, anodizing, and plasma spraying. Also, it would be possible to deposit an aluminium, or other material, coating on the conductor of the heater element, for example with arc spraying, and to oxidize the deposited material to an oxide with plasma electrolytic oxidation.
Further alternative manufacturing methods for the heater element include chemical vapour deposition, physical vapour deposition, electrochemical machining (ECM), chemical and/or electrochemical oxidation, thermo-treatment involving high temperatures of above 200°C or 300°C and exposure to oxygen, and coating or dipping involving a slurry with titanium particles, for example, followed by a sintering step. Also, the core of the heater element can be provided with a layer of titanium or aluminium or similar material (plating) where after one or more of the foregoing manufacturing methods is performed.
In a presently preferred embodiment the ceramic layer is provided with porosity such that the delivery fluid is transferred from the buffer to the vicinity of the conductor.
By providing a porous ceramic layer it is possible to configure the ceramic layer such that the delivery fluid is transferred through or along the ceramic layer enabling delivery fluid to transfer from a buffer to the conductor. This prevents the need to provide a separate buffer such as a buffer cloth.
Preferably, the ceramic layer has a porosity in the range of 10-80%, preferably 15-50%, more preferably 20-30% and most preferably the porosity is about 25%. It was shown that especially the porosity in a range of 20-30% provides an optimum in the performance of specifically the ceramic layer and the heater as a whole. Furthermore, it is shown that using plasma electrolytic oxidation to provide the ceramic layer is beneficial in that it enables control of the porosity of the produced layer.
In a presently preferred embodiment according to the invention the delivery fluid transfer element comprises the porous ceramic layer of the heater element that is configured to control the atomizing and/or vaporizing of the delivery fluid.
By using the porous ceramic layer to transfer delivery fluid towards the conductor of the heater element an effective transfer of delivery fluid becomes possible. This obviates or at least reduces the need for separate transfer means thereby rendering the unit more efficient.
In a presently preferred embodiment according to the invention the delivery fluid transfer element comprise a cartridge penetrating element.
By providing the transfer means with a penetrating element the transfer means extend from the housing of the unit in the (disposable) cartridge. Preferably the penetrating element penetrates a seal or sealing element of the cartridge when inserting the cartridge and/or connecting the primary and secondary housings.
In a presently preferred embodiment according to the invention the unit further comprises a power and/or current increasing circuit configured for providing a power increase when the heater is switched on.
By providing the power and/or current increasing circuit the power can temporarily be increased when switching on the heater. Such circuit may comprise one or more capacitors and/or one or more coils. The circuit enhances the effect of the heater and/or reduces the requirements for the power supply.
In a presently preferred embodiment a capacitor, preferably a so-called super-capacitor, is included in a circuit that provides a peak current, preferably when a user of an E-cigarette starts to inhale. When activating the heater to atomize and/or vaporize the fluid, the heater temperature has to be increased. By providing a (super) capacitor this temperature increase can be performed faster and almost instantaneously. This enables the device, for example an E-cigarette, to almost directly provide a fluid at its outlet comprising atomized and/or vaporized delivery fluid. The current increase/peak when activating the heater element leads to heat development in het heater element that is used to atomize and/or vaporize the delivery fluid. The heater element according to the invention comprises a porous ceramic layer that is preferably capable of absorbing and/or adsorbing delivery fluid. This enables the heater element to start directly with the atomizing and/or vaporizing. As a further advantageous effect the battery is not required to provide the peak current when activating the heater element. This enables providing a smaller battery, thereby enabling dimensioning an E-cigarette in conformity with the size of a conventional cigarette, for example. Furthermore, with the additional circuit comprising a (super) capacitor the battery is not subjected to peak demands and can, therefore, be operated at a more constant level. This improves the lifetime of the battery. The capacitor can be charged by the battery after the heater element is deactivated. In an advantageous embodiment the heater element is made from a titanium material that has a relatively low resistance at low temperature (e.g. 20°C) and a high resistance at a higher temperature. This enables providing a higher current to the heater element when activating the heater element, while after the heater element reached its optimal operating temperature the applied current is lower. In fact, the resistance of titanium at the vaporisation and/or atomisation temperature is optimal for the battery. With the use of the (super) capacitor the battery is no longer limiting the (minimum) resistance of the heater element, thereby enabling an improved design of the heater element and the device comprising this heater element. Especially the combination of a super capacitor with titanium wire conductor appears beneficial.
In one of the presently preferred embodiments according to the invention the super capacitor is connected to a charge-connector configured for connecting the super capacitor to an external power source for charging the super capacitor. This enables external charging of the super capacitor without the need for the battery to supply the power for charging the super capacitor. In a further preferred embodiment system does not include a battery. In this embodiment the super capacitor supplies all required energy and is charged from an external power supply. Preferably, the super capacitor has a capacity of 12 Farad, or more. This reduces the number of components of the system, reduces system weight, and immediately provides energy for vaporization/atomization. Optionally, the system is charged in the cigarette box, for example using a rechargeable battery.
In a presently preferred embodiment the conductor of the heater element is made of NiCr and preferably of Titanium. The resistance of Titanium increases more rapidly with temperature as compared to NiCr.
According to an embodiment of the present invention the power and/or current increasing circuit can be provided, together with the heater element, in the primary housing. This guarantees an effective coupling of the circuit elements that are not hindered by connecting manoeuvres with the cartridge, for example. This provides a robust unit. Furthermore, by providing the circuit and the heater element in the primary unit re-use is made possible, thereby enabling the use of stronger en more sustainable materials, for example.
The present invention further also relates to an E-cigarette assembly comprising a personal electronic delivery unit and a cartridge as described earlier.
The E-cigarette assembly provides the same effects and advantages as described for the unit.
In a presently preferred embodiment of the invention the cartridge of the assembly comprises:

a container configured for holding a delivery fluid;
a seal configured for sealing the container, wherein the seal is configured to be penetrated or removed when inserting the cartridge in the housing; and
a delivery fluid pathway arranged to transfer the delivery fluid from the cartridge to a heater element that is provided in the unit.

Preferably, the cartridge comprises a cartridge fluid transfer element configured for transferring delivery fluid from the cartridge container towards the heater element. Such cartridge fluid transfer element may comprise a wick. When in use, the delivery fluid is transferred with this wick towards the heater element that is provided in the housing, preferably in the primary housing, to enable re-use of the heater element with a further (disposable) cartridge.
Preferably, the cartridge fluid transfer element comprises a swelling wick that swells when in contact with the delivery fluid. More preferably, the swelling wick is brought in contact with the fluid when inserting the cartridge in the secondary housing and/or connecting the secondary housing to the primary housing. When swelled the swelling wick is capable of transferring delivery fluid from the cartridge container towards the heater element. Preferably, the cartridge container is configured such that the swelling brings the wick closer to the heater element.
In a further embodiment according to the invention the wick comprises a seal. The seal preferably seals the container before inserting and/or connecting the cartridge in the unit. In one embodiment the seal is penetrated when connecting the cartridge to a housing of the unit, for example by the cartridge penetrating element mentioned earlier. In another embodiment the seal is melted when connecting the cartridge to a housing of the unit. Melting can be achieved by supplying current from the battery and/or a circuit that may comprise a (super) capacitor to the seal. This provides an efficient means to remove the seal after inserting and/or connecting the cartridge to the unit and enabling transfer of delivery fluid from the cartridge container towards the heater element.
The present invention further also relates to the use of a personal electronic delivery unit and/or cartridge as described herein for delivering the delivery fluid to a person, comprising the steps of:

providing said E-cigarette assembly comprising a unit and cartridge as described earlier;
inhaling at the outlet or mouth piece to provide a subnormal pressure in the fluid path such that ambient air is sucked into the inlet; and
atomizing and/or vaporizing at least a part of the delivery fluid with the heater element that is provided in the unit and delivering atomized and/or vaporized delivery fluid at the outlet or mouth piece.

Said use provides the same effects and advantages as described for the unit, cartridge and/or assembly thereof. The use preferably involves the use of an E-cigarette assembly. Said use provides effective means to deliver a delivery fluid to a person, for example to provide the feel of tobacco smoking, without increasing health problems by burning components of the delivery fluid and/or system.
Preferably, the heater comprises a conductor with a ceramic layer. More preferably, the ceramic layer is provided using plasma electrolytic oxidation. Plasma electrolytic oxidation is preferably used as it enables control of the porosity and/or thickness of the ceramic layer.
Preferably, in use, the heater reaches a temperature in the range of 50-300°C, preferably 100-200 °C, and more preferably 120-180°C. As shown, at these temperatures a good atomisation and/or vaporisation of the delivery fluid can be achieved.
In an advantageous embodiment according to the invention the use further comprises the step of providing the delivery fluid from the cartridge container to the heater element in the housing. In fact, the delivery fluid is brought from the (disposable) cartridge to the heater element that is provided in the unit and can be used also for future cartridges. The transfer can be achieved using a wick, for example. Examples of such wick have been described earlier in relation to the cartridge.
Preferably, the use further comprises the step of providing a power and/or current increasing circuit comprising a super-capacitor. As described earlier this improves the effective operation of the unit with the cartridge, thereby providing an efficient delivery of fluid to a person.
The invention further relates to a method for producing a personal electronic delivery system and/or cartridge as described herein, the method comprising:

providing said E-cigarette assembly comprising a unit and cartridge as described earlier.

Said method provides the same effects and advantages as described for the unit, cartridge, assembly and/or use thereof. Moreover, the production method may include the steps as described herein with respect to the personal delivery system and/or the atomizing assembly.
Preferably, the production method further comprises providing an energy source configured for providing energy to the heater.
Preferably, the heater is provided as a conductor with a ceramic layer. More preferably, the ceramic layer is provided using plasma electrolytic oxidation. Plasma electrolytic oxidation is preferably used as it enables control of the porosity and/or thickness of the ceramic layer.
Preferably, the ceramic layer produced has a thickness in the range of 5-300 µm, preferably 10-200 µm, more preferably 50-150 µm, and most preferably the thickness is about 100 µm.
In an example of a plasma electrolytic oxidation process, the thickness of the ceramic layer is controlled by controlling the voltage, duration of the process, current density, electrolyte concentration and composition.
Preferably, the conductor of the heater is provided as a valve metal, preferably titanium.
In an embodiment, the conductor is provided as a spiralled metal wire, wherein the wire is provided with the ceramic layer. The spiralled heater may be provided with its central axis substantially in the longitudinal direction of the fluid path.
Preferably, the ceramic layer is provided with a porosity such that the delivery fluid is transferred from the buffer to the vicinity of the conductor by the ceramic layer. In an example of a plasma electrolytic oxidation process, the porosity of the ceramic layer is controlled by controlling the voltage and the duration of the process. Preferably, the ceramic layer is provided with a porosity in the range of 10-80%, preferably 15-50%, more preferably 20-30%, and most preferably the porosity is about 25%.
In an embodiment, the buffer is provided substantially surrounding the heater, wherein the buffer is provided with openings configured for transferring delivery fluid to the heater. The buffer may be formed by a tubular container, wherein the openings are provided in the wall of said container for transferring delivery fluid from the buffer to the fluid path, and to the heater. Preferably, the openings are configured to enable a venturi effect for transferring delivery fluid to the heater. Optionally, the openings may be provided in a groove. For example, the openings or holes may be formed by laser cutting, drilling, machining, electrochemical machining, punchen, stamping, pressing, die cutting, puncturing or otherwise. Moreover, the buffer may be produced including the opening by moulding.
The production method may optionally comprise providing a power and/or current increasing circuit configured for providing a power and/or current increase when the heater is switched on. Preferably, the circuit comprises a super-capacitor. Preferably, the super-capacitor is connected to a charge-connector configured for connecting the super-capacitor to an external power source for charging.
Further advantages, features and details of the invention are elucidated on the basis of preferred embodiments thereof wherein reference is made to the accompanying drawings, in which:

Figure 1 shows an E-cigarette according to the invention;
Figure 2A-V shows configurations of the heater element according to the invention;
Figure 3A-B shows a setup of a plasma electrolytic oxidation chamber to produce the heater element of figure 2; and
Figure 4 shows the Voltage as function of time in the manufacturing of the heater element in the chamber of figure 3;
Figure 5 shows a heater element according to the invention;
Figure 6A-B shows embodiments of a power/current increasing circuit;
Figure 7A-C shows embodiments of the cartridge according to the invention;
Figure 8 shows the resistance of electric heater elements in relation to temperature titanium and NiCr; and
Figure 9 an alternative embodiment of an E-cigarette according to the invention.

E-cigarette 2 (Figure 1) comprises primary housing 4 and secondary housing 6 with cartridge 8. In the illustrated embodiment secondary housing 6 is re-usable and cartridge 8 can be changed by opening and/or removing mouth piece 10. It will be understood that the invention can also be applied to units with other configurations and that the illustrated embodiments is for exemplary purposes only. For example, secondary housing 6 can be disposable, preferably together with cartridge 8.
Details, including connections between components, that are known to the skilled person from conventional E-cigarettes have been omitted from the illustration to reduce the complexity of the drawing.
Primary housing 4 comprises (LED) indicator 12 with air inlet 14, air flow sensor 16, switch 18 and battery 20. Air from inlet 12 is provided along air path 22 to sensor 16. Switch 18 comprises an electronic circuit board that is connected to the relevant components of cigarette 2. From sensor 16 inhaled air follows air path 22 in air gap 24 between battery 20 and the inside of primary housing 4 towards the other end 26 of primary housing 4. Optional air guides 28 guide the air towards heater element 30, preferably such that the air is provided in a substantially transverse direction to the central axis 32 of heater element 30. Connectors 34 connect heater element 30 to battery 20. In the illustrated embodiment current increasing circuit 36 is provided. Connector 38a of primary housing 4 connects primary housing 4 to connectors 38b of secondary housing 6.
Fluid transfer element 40 enables transfer of delivery fluid from cartridge 8 towards heater element 30. In the illustrated embodiment transfer element 40 is a wick 41 from wicking material such as silica, cotton, etc.
Battery 20 can be a rechargeable battery including the required connections to enable recharging.
Cartridge 8 comprises the delivery fluid such as the E-liquid (for example a mixture of glycerol, propylene glycol, nicotine). B
In one of the preferred embodiments heater element 30 comprises a wire of metallic titanium core 30a with ceramic titanium oxide layer 30b around metallic core. The E-liquid is absorbed and/or adsorbed in the porous ceramic layer. Wire 30 is heated by passing an electric current through metallic titanium core. Wire 30 is heated and the E-liquid is evaporated and/or atomized. The mixture is provided to outlet 10b of air path 22 at mouth piece 10.
Heater 30 achieves an improved temperature control and the ability to control the amount of E-liquid evaporating in time by varying the characteristics of the porous ceramic layer, such as thickness, size of pores, and porosity.
When inhaling at outlet 10b an under pressure in air paths 22, 24 is achieved. Air is sucked in through inlets 14. Sensor 16 detects an air flow and circuit board of switch 18 sends an indication signal to indicator 12. Battery 20 provides electricity to heater 30 that heats the E-liquid supplied from cartridge 8 and vaporizes and/or atomizes the liquid such that a user may inhale the desired components therein.
In the illustrated embodiment heater 30 has its longitudinal axis 32 substantially transverse to air path 22. It will be understood that other configurations are also possible in accordance with the invention.
Several embodiments of a heater element according to the invention will be illustrated. Heater 42 (Figure 2A) comprises a resistance heating material 44a as conductor and porous ceramic layer 44b. Heater 46 (Figure 2B) is wound as a solenoid 48 (Figure 2C) similar to heater 28 as illustrated in Figure 1. In an alternative configuration heater 50 is configured as a toroid (Figure 2D), or flat coil 51 (Figure 2E), or flat spiral 52 (Figure 2F), for example.
In the illustrated embodiment of system 2 buffer 30 is provided around air path 28 and heater 32 (see also Figure 2G). In an alternative embodiment liquid reservoir 54 is provided inside the solenoid of heater 56 (Figure 2H).
A further alternative configuration includes heater 58 (Figure 2I) wound as toroid structure with liquid passing through the inside of the toroid structure and air flow passing around toroid structure. Another alternative configuration includes heater 60 (Figure 2J) formed as a flat coil. Also, heater 62 (Figure 2K) may comprise a layer of path of resistance heating material 64 as conductor on coated porous ceramic layer 66, or alternatively heater 68 may comprise a conductor layer 70 with coated porous ceramic elements or spots 72 provided thereon (Figure 2L). Alternatively, heater 74 comprises conductor layer 76 and ceramic layer 78 (Figure 2M), and optionally additional ceramic spots 80 (Figure 2N). Another embodiment comprises porous ceramic layer 82 with conductor 84 wound in a spiral configuration (Figure 2O).
Other embodiments include conductor tube 86 with static mixing form 86a coated with ceramic layer 88 (Figure 2P and 2Q). As a further alternative, conductor 90 is a tube (Figure 2R) with a ceramic layer 92. Tube 90a can be filled with liquid on the inside and having air flow on the outside (Figure 2S) or tube 90b has air flow on the inside and liquid buffer on the outside (Figure 2T). Optionally, a ceramic layer is provided on the inside and the outside of tube 90. Also, tube 90 may comprise a number of smaller tubes or wires 94 with resistance heating material and ceramic material (Figure 2U). A further alternative configuration (Figure 2V) involves resistance heating metallic foam or sponge 96 coated with porous ceramic material 98.
The disclosed embodiments for heater 32 provide examples of heaters according to the invention that can be applied to systems 2.
Heater elements according to the invention are preferably manufactured using plasma electrolytic oxidation. As an example, for illustrative reasons only, below some manufacturing methods for some of the possible configurations for the heater element according to the invention will be disclosed.
In a first embodiment of the heater element, plasma electrolytic oxidation of titanium wire that is directly connected to an anode is performed.
For the plasma electrolytic oxidation use is made of a plasma electrolytic chamber 102 (Figure 3 A). Work piece 104 is connected to the anode 106. Work piece 104 is clamped/fixed between two screws or clamps 108 that are connected to the ground/earth (anode 104) of a power supply. In the illustrated embodiment cathode 110 comprises stainless steel honeycomb electrode 112 that, in use, is placed at close distance above work piece 104. Electrolyte 114 flows between electrode 112 and anode 106, and effectively flows upwards through honeycomb electrode 112 together with the produced oxygen and hydrogen. Electrolyte effluent 116, together with the hydrogen and oxygen, is then cooled and optionally returned to chamber 102. In the illustrated embodiment the temperature of electrolyte 114 increases from around 11°C entering plasma electrolytic oxidation chamber 102 to 25°C exiting chamber 102 and is then cooled off using a heat exchanger (not shown).
In the illustrated chamber 102 two power supplies (Munk PSP family) are connected in series: one of 350 Volt and 40 Ampere and a second of 400 Volt and 7 Ampere resulting in a maximum of 750 Volt and 7 Ampere with resulting maximum power of 5.25 kW. The power supplies can be connected directly to anode 106 and cathode 110 resulting in direct current (DC) operation of the plasma. An optionally added switching circuit provides the option to operate the plasma with DC pulses. The frequency of the pulses can be set between DC and 1 kHz and different waveforms can be chosen (block, sine, or triangle). Plasma electrolytic oxidation is preferably performed in a pulsed current mode with a frequency (on-off) of about 1000 Hz, preferably with the current set at a fixed value and the voltage increases in time as a result of growing of the porous oxide layer. Current between 1 and 7 Ampere can be used to produce a ceramic layer.
To produce a heater element according to the invention, in chamber 102 titanium wire 202 (Figure 3 B) is placed as work piece 104 on top of a titanium plate 204 that is connected to the stainless steel anode. Optionally, the anode is directly connected to wire 202. The electrolyte comprised 8 g/l NaSiO₃*5H₂O and 15 g/l (NaPO3)₆. Titanium wire is used made from titanium grade 1, with a diameter of 0.5 mm and 60 cm in length. The wire is coiled and connected to the anode. A potential higher than 500 volts is applied between the anode and cathode resulting in micro arc discharges on the surface of the titanium wire. On the surface of the wire, the metallic titanium is oxidized to titanium oxide with addition of silicates and phosphates from the electrolyte. The metallic layer is converted to a porous ceramic layer containing titanium oxides, phosphates and silicates. This results in a heater element 302 (Figure 5) according to the invention.
Current increasing circuit 402 (Figure 6A) comprises battery 404, trafo 406, heater element 408 and (super) capacitor 410. Other components in circuit 402 include diode 412, resistance 414, switch 416 responding to inhaling, transistor 418. It will be understood that components in circuit 402 can be replaced with other components and/or additional components can be applied. For example, alternative circuit 420 (Figure 6B) comprises battery 422, heater element 424, capacitor 426, switch 428, resistor 430 and diode 432.
When starting to inhale capacitor 410, 426 supplies additional current to heater element 408, 424 to accelerate the temperature increase of heater element 408, 424 and to start atomizing and/or vaporizing almost immediately. Preferably, the heater element is of a titanium material that exhibits a relatively low resistance at room temperature and a higher resistance at an increased temperature thereby enabling a fast response time to the activation signal.
Different embodiment for cartridge 8 can be envisaged. In one embodiment cartridge 502 (Figure 7A) is provided with container 504 filled with E-liquid. Seal 506 seals container 504 before connecting container 504 to primary housing 4. Wick element 508 penetrates seal 506 when connecting primary and secondary housings 4, 6. In the illustrated element wick element 508 acts as cartridge penetrating element and can be integrated with delivery fluid transfer element/wick 40 that is connected to heater element 30. Optionally, wick 40 can be provided as an extension to porous layer 30b. In the illustrated embodiment edge 510 is provided to support wick element 508 after connecting primary and secondary housings 4, 6.
In another embodiment cartridge 602 (Figure 7B) comprises container 604 filled with E-liquid and wick element 606. Wick element 606 is provided with seal 608 at least at a part of its outer surface. Seal 608 is penetrated when connecting secondary housing 6 to primary housing 8 with a penetrating element, for example provided in combination with wick 40. Optionally, seal 608 is melted by providing current from battery 20 and/or a (super) capacitor when connecting secondary housing 6 to primary housing 8.
In a further embodiment cartridge 702 (Figure 7C) comprises container 704 filled with E-liquid. Swelling wick 706 is provided above seal 708 and below ball or ball valve 710. After connecting primary and secondary housings 4, 6 wick 706 comes into contact with the E-liquid swells and moves towards heater element 30 to transfer E-liquid in that direction.
In a presently preferred embodiment the conductor of the heater element is made of NiCr and preferably of Titanium. The resistance of Titanium (Figure 8) increases more rapidly with temperature as compared to NiCr. This is illustrated with the linear relation for NiCr (y=0.0011x+2.164) as compared to the linear relation for Titanium (y=0.0104x+1.5567) defining the linear relation of the measured resistances at specific temperatures.
In a further embodiment of E-cigarette 802 (Figure 9) heater 32 is supplied with energy through connector 804 from super capacitor 806. Capacitor 806 is charged via external connector 808. Capacitor 806 can be charged (semi)-directly and/or indirectly. Such indirect charging can be performed in connection with cigarette box 810 having cigarette storage compartment 812 and battery compartment 814 with battery 816. In a charging state charge connector 818 contacts connector 808 and super capacitor 806 is being charged. In the illustrated embodiment battery 816 is rechargeable through connector 820.

To illustrate the manufacturing of heater element 30 three experiments will be discussed: 1) 0.5 Ampere for 15 minutes, 2) 1 Ampere for 15 minutes and 3) 2 Ampere for 15 minutes. The mass and diameter of the wire was measured before and after plasma electrolytic oxidation. The wire was placed in water for 5 minutes and the mass was measured as an indication of the amount of water adsorbed on the wire. The voltage as a function of time of the three different current settings can be seen in Figure 4, and some further material information before and after oxidation is presented in Table 1.

Table 1: Material information

	Weight (mg)
	1	2	3
Before PEO (mg)		525.49	529.82
After PEO (mg)	528.37	539.42	548.71
After heating (mg)	528.09	539.23	547.67
After 5 min in water (mg)	675.7	692.23	705.42
Thickness (µm)	36	71	113
Volume geads (ml)	0.15	0.15	0.16
Volume oxide layer (ml)	0.45	0.51	0.59
Porosity (%)	32.71	29.87	26.73

Ceramic wires were manufactured at different process conditions, including with 5 Ampere (wire 1) and 1 Ampere (wire 2) for processing time of an hour. The results are shown in Table 2.

Table 2: Thickness of ceramic layer porosity and adsorption of two ceramic titanium wires

	Time + current	Ceramic thickness	Porosity	Adsorption	Resistance
Wire
1	1hr @ 5A	55 µm	45%	21 µl	1.4 Ω
Wire
2	1 hr @ 1A	30 µm	50%	13 µl	1.3 Ω

Wire 1: Before plasma electrolytic oxidation (PEO)
L = 0.5 m, D = 0.500 mm, R = 1.2 Ω, R_calculated = 2.44 Ω/m, Adsorption (water) = 4 µl Wire 1: After PEO (5 A for 60 minutes)
L = 0.5 m, D = 0.610 mm, R = 1.3-1.4 Ω, Adsorption (water) = 21 µl, Porosity = 44 %
Wire 2: Before PEO:
L = 0.5 m, D = 0.500 mm, V = 9.8 e-8 m³, m = 4.2992 e-4 kg, ρ = 4379 kg/m³
Wire 2: After PEO (1 A for 60 minutes)
L = 0.5 m, D = 0.5610 mm, V = 1.236 e-8 m',m = 4.512 e-4 kg, ρ = 3650 kg/m³, m_{oxide layer} = 2.13 e-5 kg, V_{oxide layer} = 2.56 e-8 m³, M_{estimate without porosity} = 4.452 e-5 kg, Porosity = 50 (%, Calculated adsorption = 12.8 µl

It will be understood that for alternative wires other conditions would apply. For example, for a wire having a diameter of 0.1 mm R_calculated = 61 Ω/m. Such wire with a length of 6.5 cm will give a resistance of 4 K2. With an oxide thickness of 100 µm an amount of 1.3 µl is adsorbed. 150 µm gives 3.1 µl and 200 µm gives 5.4 µl.
The experiments illustrate the manufacturing possibilities of the heater element for the system according to the present invention.
Further experiments have been conducted to produce other configurations for the heater. In one such further experiment a metal foil, preferably an aluminium foil, was used as starting material on which a porous metal (aluminium) oxide layer is provided, preferably in a plasma electrolytic chamber that is described earlier. Table 3 shows measured values of plasma electrolytic oxidation with constant current at 5 ampere for 9 minutes. Aluminium foil of 13 µm thickness was oxidized with a resulting thickness of aluminium oxide of 13 µm. Table 3: Voltage, current, temperature of electrolyte going in the plasma electrolytic oxidation chamber (Tin) and going out the plasma electrolytic oxidation chamber (Teff) for constant current of 5 A.

t min. Voltage V Current A Tin °C Teff °C

0,167 434 5

0,5 447 5

1 461 5

2 476 5 10.1 18.8

4 487 5 10.9 20.4

6 499 5 11.3 21.4

9 515 5
Table 4 shows the reproducibility of the process. Table 4: Voltage, current, temperature of electrolyte going in the plasma electrolytic oxidation chamber (Tin) and going out the plasma electrolytic oxidation chamber (Teff) for constant current of 5 A.

t min. Voltage V Current A Tin °C Teff °C

0,167 435 5

0,5 448 5

1 460 5

2 474 5 11.3 19.7

4 488 5

6 495 5

8 505 5
Table 5 shows the voltage and current for plasma electrolytic oxidation of aluminium foil at constant current of 2 A. Result was a 13 µm thick aluminium oxide layer. Table 5: Voltage and current of plasma electrolytic oxidation with constant current of 2A.

t min. Voltage V Current A

1 380 2

2 415 2

3 429 2

4 437 2

5 443 2

6 448 2

7 452 2
Table 6 shows the voltage and current of the plasma electrolytic oxidation of aluminium foil with pulsed constant current of 1 kHz at 5 Ampere. Table 6: Voltage and current of pulsed constant current of 1 kHz

T min. Voltage V Current A

0.167 470 5

0.5 485 5

1 491 5

2 502 5

4 514 5

6 523 5
In a further experiment, plasma electrolytic oxidation was used to provide a porous, flexible and elastic ceramic layer of >70 µm on titanium foil. Plasma electrolytic oxidation grows a titanium oxide layer which is known to be ceramic (TiO₂). Electrolyte was used with 8 g/l Na₂SiO₃*5H₂O (Natrium metasilicate pentahydrate) and 15 g/l (NaPO₃)₆, (Natrium hexametaphosphate). The electrolyte is pumped into the reaction chamber to act as the electrolyte and as a coolant. Titanium foil was used from titanium grade 2 with a thickness of 124 µm. In the manufacturing process the voltage increases as a function of time. This increase signifies an increased resistance and can possibly be explained by the growth of the titanium oxide (TiOx) layer. A thicker TiOx layer acts like an insulating layer between the metal and electrolyte. The resulting Voltage development in time can be seen in Table 7. Table 7: Voltage and current as function of time for production of ceramic layer on titanium foil with plasma electrolytic oxidation

Time min. Voltage V Current A

0.166667 435 6

0.5 510 6

1 540 6

2 551 6

3 553 6

4 554 6

5 556 6

6 556 6

7 557 6

10 557 6
The resulting foil structure can be processed further involving electrochemical machining. For example, use can be made of dissolution of Titanium grade 2 to make perfect squared shaped channels. With electrochemical machining (ECM) Titanium grade 2 is locally dissolved in a very controlled manner until the ceramic layer is reached. The finished result has to be well defined channels with squared edges and no residue on top of the ceramic layer. The ECM process is used with a cathode with the inverse shape of the product placed on top of a Titanium plate that serves as the anode. A potential is placed between the cathode and anode causing the anode to dissolve. Electrolyte concentration is 5 MNaNO₃. Current density can be varied from 20-150 A/cm². The best results were realized with current densities of >60 A/cm². Current is operated in a pulsed mode with the time the current is on and off can be varied. Best results were realized with on/off ratio of 16 - 80 and pulse on from 0.05 until 10 ms and pulse off from 1 ms until 160 ms. This additional processing step may also be applied to other configurations for the heater.
In a presently preferred embodiment the heater element is made from a titanium wire, or less preferably from NiCr wire. Figure 8 shows the resistance of electric heater elements in relation to temperature for both materials. As mentioned earlier the use of titanium for the heater element is beneficial.
The above described experiments illustrate the possibility to manufacture the different configurations of the heater element and to implement such configuration in an E-cigarette, for example. Many modifications can be envisaged. For example, the system may be provided with a solar panel on its outer surface, e.g. the outer surface of the housing. The solar panel may be configured for charging the battery or capacitor.
The present invention is by no means limited to the above described preferred embodiments thereof. The scope of the invention is defined by the following claims.

Claims

Personal electronic delivery unit, comprising:
- a primary housing (4) comprising an energy source (20) and having a first end with an air inlet (12) and a second end with a primary connector configured for connecting to a secondary housing (6) configured for holding a cartridge (8) with a delivery fluid and having an outlet or mouth piece (10);

- a fluid path substantially extending between the air inlet (12) and the outlet or mouth piece (10);

- a heater element (30 that is provided in, at or close to the fluid path configured for heating the delivery fluid such that at least a part of a delivery fluid atomises and/or vaporises in the fluid path, wherein the heater element (30) is in use connected to the energy source (20) configured for providing energy to the heater element (30), and wherein the heater element (30) is provided in and/or attached to the primary housing (4); and

- a delivery fluid transfer element (40) that is configured for transferring delivery fluid from the cartridge (8) to the fluid path; and
wherein the heater (30) comprises a conductor (30a) and a porous ceramic layer (30b) that is configured to control the atomizing and/or vaporizing, characterised in that the ceramic layer is provided on or at the conductor (30a) with plasma electrolytic oxidation.
Personal electronic delivery unit according to claim 1, wherein the ceramic layer has a thickness in the range of 5-300 µm, preferably 10-200 µm, more preferably 50-150 µm, and most preferably the thickness is about 100 µm.
Personal electronic delivery unit according to one or more of the foregoing claims, wherein the ceramic layer is provided with a porosity such that it is capable of absorbing and/or adsorbing the delivery fluid, and wherein preferably the ceramic layer has a porosity in the range of 10-80%, preferably 15-50%, more preferably 20-30%, and most preferably the porosity is about 25%.
Personal electronic delivery unit according to one or more of the foregoing claims, wherein the heater (30) comprises a valve metal, preferably titanium.
Personal electronic delivery unit according to one or more of the foregoing claims, wherein the delivery fluid transfer element (40) comprises the porous ceramic layer.
Personal electronic delivery unit according to one or more of the foregoing claims, wherein the delivery fluid transfer element (40) comprises a cartridge penetrating element.
Personal electronic delivery unit according to one or more of the foregoing claims, further comprising a power and/or current increasing circuit configured for providing a power and/or current increase when the heater is switched on, wherein the circuit preferably comprises a super-capacitor, and wherein the super-capacitor preferably is connected to a charge-connector configured for connecting the super-capacitor to an external power source for charging.
E-cigarette assembly comprising a personal electronic delivery unit according to one or more of the foregoing claims and a cartridge.
E-cigarette assembly according to claim 8, the cartridge (8, 502) comprising:
- a container (504) configured for holding a delivery fluid;

- a seal (506) configured for sealing the container (504), wherein the seal (506) is configured to be penetrated or removed when inserting the cartridge (502) in the secondary housing (6) of the personal electronic delivery unit; and

- a delivery fluid pathway arranged to transfer the delivery fluid from the cartridge to a heater element that is provided in the personal electronic delivery unit.
E-cigarette assembly according to claim 9, the cartridge further comprising a cartridge fluid transfer element (508) configured for transferring delivery fluid from the cartridge container towards the heater element, wherein the cartridge fluid transfer element preferably comprises a swelling wick that swells when in contact with the delivery fluid
E-cigarette assembly according to claim 10, wherein the wick comprises a seal, wherein preferably the seal is penetrated when connecting the cartridge to a housing of the unit, and wherein preferably the seal is melted when connecting the cartridge to a housing of the unit.
Method for delivering a delivery fluid to a person, comprising the steps of:
- providing an E-cigarette assembly according to one or more of the claim 8-11;

- inhaling at the outlet or mouth piece to provide a subnormal pressure in the fluid path such that ambient air is sucked into the inlet; and

- atomizing and/or vaporizing at least a part of the delivery fluid with the heater element that is provided in the unit and delivering atomized and/or vaporized delivery fluid at the outlet or mouth piece.
Method for producing a personal electronic delivery unit and/or cartridge, comprising the steps of providing an E-cigarette assembly according to one or more of the claims 8 - 11, wherein preferably, in use, the heater reaches a temperature in the range of 150-750°C, preferably 200-500°C, more preferably 250-400°C.
Method according to claim 13, further comprising the step of providing the heater element with a conductor having a ceramic layer, wherein providing the ceramic layer preferably comprises performing plasma electrolytic oxidation, and after providing the ceramic layer on one side of the conductor, preferably removing at least a part of the conductor material with the use of electrochemical machining, preferably wherein, in use, the heater reaches a temperature in the range of 150-750°C, preferably 200-500°C, more preferably 250-400°C.
Method according to one or more of the claims 13-14, further comprising one ore more of the steps of:
- providing the delivery fluid from the cartridge container to the heater element in the housing; and

- providing a power and/or current increasing circuit comprising a super-capacitor.