The present invention relates to a cartridge for a personal electronic delivery system that is used for delivery of a delivery fluid to a person. Such system 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 mouthpiece. E-cigarettes further comprise a battery and a heater that is provided with energy from the battery. In conventional E-cigarettes a cartridge or reservoir comprises a heater that is winded around a so-called wicking material that acts as a buffer. The heater is switched on and off with a flow detector that is located in the inlet, for example. The delivery fluid is vaporised and/or atomised by the heater to enable inhaling of the liquid.

A problem with conventional E-cigarettes is the insufficient control of supply of the E- liquid, or other delivery liquid to the heater when the heater is in use. This may result in providing an insufficient amount of E-liquid to the heater element, or providing too much E-liquid. A further problem is that the supply is not constant and depends on the frequency of inhaling/atomizing and/or conditions like surrounding temperature etc. This results in vaporizing and/or atomizing of the E-liquid having a varying quality. In addition, such insufficient control may lead to an E- cigarette that is uncomfortably warm to hold, burning of the E-liquid that may cause undesirable components to be present in the inhaled flow, thereby possibly posing a problem in relation to a person's health. Due to the insufficient temperature control using conventional E-cigarettes may even result in release of heavy metals.

The present invention has for its object to provide a cartridge for a personal electronic delivery system, such as an E-cigarette, and enable a more controllable atomization and/or vaporization thereby reducing and/or preventing the aforementioned problems.

This object is achieved with the cartridge for a personal electronic delivery system according to the present invention, the cartridge comprising:

- a cartridge housing having a first end with an inlet and a second end with an outlet, and comprising a tubular element that is provided in the cartridge housing;

- a fluid path in the tubular element substantially extending between the inlet and the outlet;

- a reservoir for holding a delivery fluid, the reservoir comprising a number of openings that are configured to transfer delivery fluid to the fluid path, wherein the number of openings is at least two, and the reservoir is configured to hold an amount of delivery fluid and an amount of gas; and - a heater that is substantially provided in the tubular element and is configured for heating the delivery fluid such that at least a part of the delivery fluid atomises and/or vaporises in the fluid path,

wherein, when activated, the heater is configured to heat the gas in the reservoir such that the temperature of the gas in the reservoir rises with a temperature increase in the range of 1.5 to

7.5 °C and delivery fluid is transferred from the reservoir to the fluid path with the heater. Providing a fluid path from the inlet to the outlet, preferably embodied as a mouth piece, enables inhaling at the outlet to draw/suck in ambient air into the system and/or cartridge, for example. This provides a personal electronic delivery system, such as E-cigarettes that also include so-called E-cigars, and vaporizers for pharmaceutical and nutraceutical applications (examples are vaporizers for CBD and THC vaporization ). The heater that is included in the system 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 heater element 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.

The cartridge housing has a first end with an inlet and a second end with an outlet. The outlet is preferably shaped as or connected to a mouthpiece. The cartridge inlet is provided with connecting means, for example screw thread, enabling connecting the cartridge to the battery or energy assembly of a personal electronic delivery system. The connecting means are preferably provided at the first end of the cartridge. When connected to a battery assembly, the inlet of the cartridge is in fluid communication with an outlet of the battery assembly. The connecting means are preferably suitable for a releasable connection to the battery assembly, i.e. the cartridge may be disposable.

The cartridge according to the invention is also referred to as the atomiser assembly. In use an air flow is provided from the cartridge inlet to the outlet thereby defining a fluid path. In the cartridge according to the present invention the fluid path substantially extends between inlet and outlet of a tubular element that is provided in the cartridge housing. The heater or heater element is substantially provided in the tubular element and in use heats the delivery fluid such that at least a part of the delivery fluid atomises and/or vaporises in the fluid path. Preferably, the heater is provided as part of the cartridge. Alternatively, the heater is part of an energy assembly that together with the cartridge builds the personal electronic delivery system, such as an E-cigarette.

Optionally, the cartridge is filled with delivery fluid (E-liquid) using an ampule. Such ampule is place in or on the cartridge and provides the cartridge with the fluid. For example, if the ampule is punched when assembling the device its contents may fill the reservoir. It will be understood that other configuration can also be envisaged.

Experiments showed that the specific temperature increase of the gas was responsible for providing a desired amount of E-liquid through the openings into the fluid path such that the heater was capable of atomizing/vaporizing the liquid. Surprisingly, as a further effect, it was noticed that the cartridge according to the invention was capable of producing more vape (aerosols), having more particles in the range of 1 to 5 micron which is beneficial for the uptake in the blood stream. Users experienced higher nicotine delivery.

In a presently preferred embodiment the number of openings is between 2 and 15, preferably between 3 and 13, more preferably between 5 and 10, such as 6 or 8 openings, for example.

Providing a number of openings further improves the overall quality of the atomizing/vaporizing.

Preferably, the diameter of the openings is in the range of 0.15 to 0.5 mm, more preferably in the range of 0.2 to 0.35 mm, and most preferably in the range of 0.25 to 0.30 mm. It was shown that in combination with the E-liquid characteristics these diameters effectively provided a desired amount of E-liquid to the fluid path in response to an activation of the cartridge.

In presently preferred embodiments of the invention the temperature increase of the gas in the reservoir, when the heater is activated, is in the range of 2 to 5 °C, and more preferably in the range of 2.5 to 4.5 °C. It was shown that this specific temperature increase effectively provided a desired amount of E-liquid to the fluid path in response to an activation of the cartridge.

In some of the embodiments of the present invention the inner surface of the tubular element is at least partly provided with an insulating layer such as a coating or plating, or insulating element, such as another tubular element. According to the present invention also an embodiment of a tubular element that is entirely, or at least substantially, made from an insulating material is envisaged. The heater is positioned such that at least a part of the heater extends within the tubular element, and more specifically within that part of the tubular element that is provided with the aforementioned insulating layer or insulating element.

Positioning the heater at least partly within the insulated part of the tubular element significantly improves the temperature control of the cartridge when in use. The insulating prevents the outer surface of the cartridge becoming uncomfortably warm for a person to hold the cartridge and possibly the personal electronic delivery system as a whole. Furthermore, providing the insulated tubular element substantially around at least a part of the heater element maintains the energy, specifically the heat, within the heater and its direct surrounding. This reduces the energy demand for the personal electronic delivery system such as an E-cigarette and is provided with a cartridge according to the present invention. Furthermore, providing the heater at least partly within an insulating part of the tubular element enables an improved temperature control thereby optimizing the atomization and/or vaporization. The fluid is transported towards the heater and/or the vicinity of the heater by fluid transfer means that are specifically configured for this transfer of fluid from the reservoir to the fluid path. The tubular element is preferably shaped as a tube, pipe, conduit, case or the like. Optionally, the insulating layer contributes to the correct positioning of the heater.

The material of the cartridge may comprise metal, such as stainless steel and/or aluminium and/or brass, and/or also plastic materials that are relatively easy to manufacture.

The reservoir may comprise a container, i.e. a holder, and/or a buffer material acting as a buffer, such as a cloth or wicking material. In a presently preferred embodiment the reservoir is provided as a container, and openings formed in the walls of said buffer enable fluid to pass from the buffer through the openings to the fluid path.

Preferably, the heater comprises a conductor and a ceramic layer that is configured to control the atomizing and/or vaporization, and wherein the ceramic layer is a porous ceramic layer.

Also preferably, the heater element comprises a wire with a diameter in the range of 0.15 to 0.60 mm, preferably in the range of 0.15 to 0.50 mm, more preferably in the range of 0.20 to 0.30 mm, and most preferably is about 0.25 mm. Preferably, the wire diameter is designed in view of other characteristics such as the battery power and cartridge size. For example, small size wires can be used in combination with relatively small devices. Large size wires can be used in combination with larger devices and/or larger batteries that may deliver more than 20 Watt, for example.

In the preferred embodiments of the invention the heater element comprises a 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.

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 E-liquid. This prevents undesired burning of components. Furthermore, the ceramic layer prevents the release of heavy metals. As a further advantage of such heater element when used in combination with the cartridge and/or device according to the invention is that the heater element can be re-used several times. This provides an effective heater element. Also the ceramic layer enables adsorption and/or absorption of the E-liquid in the pores of the ceramic layer. In addition, the pores enable direct evaporation when the heater is activated. Also, the pores adsorb the liquid and provide the liquid over substantially the whole surface. Furthermore, the heater is cooled by the evaporation process thereby preventing overheating the element.

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. Another advantage of providing a porous layer is that it allows windings of the heater element to be closer to each other while still preventing electrical shortcuts between the different windings. This further improves the heater element that can be used in an embodiment of the invention.

In a presently preferred embodiment according to the invention the ceramic layer has a thickness in the range of 5-300 μπι, preferably 10-200 μπι, more preferably 15-150 μπι and most preferably a thickness is about 100 μπι.

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.

Preferably, the ceramic layer is provided on or at the conductor with plasma oxidation. The heater element is preferably made from a titanium material, or other suitable material, on which a porous metal oxide layer, such as titanium oxide, is grown with plasma electrolytic oxidation (PEO). Plasma electrolytic oxidation enables that a relatively thick titanium oxide layer is grown from the titanium (>130 μπι) by oxidizing (part of) the titanium to titanium oxide. 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 μπι thickness, with resulting in a flexible and elastic ceramic layer. One of the advantageous effects of using plasma 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 electrical resistance achieving a relatively fast heating process. The wire is coated on the other side through plasma oxidation. Plasma oxidation is done by placing the titanium wire in an electrolyte. For example, the electrolyte comprises 15 g/1 (NaP03)6 and 8 g/1 Na2Si03.5H20. 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 oxidation process on the anode wire and creates a ceramic layer.

As the wire is small sized (for example about 250 micron) it has a relative high electrical resistance of about 61 Ohm/m, for example. 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 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 according to the present invention, the heater comprises a spiralled metal wire as the conductor with the wire being provided with the ceramic layer. It will be understood that other configurations and/or shapes of the heater are possible in accordance with the present invention.

In a presently preferred embodiment 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 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 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 present invention the transfer means comprise openings that are provided in a tubular element, wherein the openings are configured for transferring delivery fluid from the reservoir to the heater.

The reservoir may be formed by a tubular container with an outer surface and an inner surface, wherein the openings are provided in the inner surface or inner wall of the container to transfer delivery fluid from the reservoir to the fluid path wherein the heater is positioned.

Preferably, the E-liquid/delivery fluid is substantially transported from the buffer to the heater by the pressure caused by the temperature increase of the gas in the container, instead of being substantially transported by a so-called venturi effect when a user inhales and an air flow is started. This obviates the need for a wick or similar element and enables effective control of the process.

Providing the buffer substantially around the heater enables fluid to be delivered through a number of small openings in the inner surface (area) of the buffer compartment which is filled with liquid. The heating element with porous ceramic layer is positioned on the other side of the opening(s). Liquid is transferred to the heating element by capillary action. Alternatively, or in addition thereto, liquid can be transferred by gravity. A low temperature the relative high viscosity and surface tension prevents the liquid from leaking or dripping. When the liquid is heated, the drop in viscosity and surface tension causes the liquid to drip on the heater. If the heating element is heated by an electric current, liquid is evaporated from the ceramic layer and the liquid in the opening(s) is heated by the element. Due to the higher temperature caused by the heating elements the viscosity decreases and the liquid is adsorbed on the ceramic layer through the openings or holes. The holes are preferably made in a metal tube since this withstands the heat. This provides a robust supply of delivery fluid to the heater.

In a presently preferred embodiment the tubular element is a stainless steel or aluminium tube having a diameter of about 4 mm with a wall thickness of about 0.3 mm having a tube length of about 29 mm. In alternative embodiments the tubular element is made of ceramic material, glass, polymer material. This is optionally also possible for other components.

For example, the openings or holes may be formed by laser cutting, drilling, machining, electrochemical machining, punching, stabbing, pressing, die cutting, puncturing or otherwise. Moreover, the buffer may be produced including the opening by moulding.

The heater element enables an improved temperature control as compared to conventional systems. This provides an optimal temperature thereby maintaining viscosity of the e- liquid/delivery fluid around its desired value. This improves the evaporation process.

The openings acting as transfer means can be shaped as openings having a diameter, with the diameter in the earlier described range(s). Alternative shapes of the opening are also possible in accordance with the present invention including slots, slits and/or grooves. Optionally, the opening in the tubular element are provided with small tubes having a desired through flow diameter. In a presently preferred embodiment the size and/or shape of the openings is designed in close relation to the characteristics of the delivery fluid or E-liquid.

In a presently preferred embodiment the design of the openings and the E-liquid composition is such that at a first low temperature when the delivery system is not in use the E-liquid remains in the reservoir due to the relatively high viscosity of the E-liquid. The glycerol/propylene glycol ratio preferably is in the range of 70/30 to 100/0, such as 90/10.

Reducing the diameter of the openings to about 0.2 mm enabled a different ratio for the glycerol/propylene glycol in a range of about 50/50 to 90/10, preferably 2/1. Further reducing the diameter of the opening to about 0.15 showed a ratio for the glycerol/propylene glycol in the range of 1/1 to 0/1. In the examples the E-liquid may comprise nicotine in the range of 20 mg/ml.

Optionally, nicotine is dissolved in the glycerol with a preferred concentration of about 18 mg/ml or E-liquid. Flavouring is provided in the glycerol and/or propylene glycol. This design was tested with eight openings having a diameter of 0.25 mm. Fluid remained in the cartridge when the system was not in use. When the heater element was heated the cartridge liquid was also heated and due to the temperature sensitivity of the viscosity of the E-liquid the viscosity was significantly lower in use. This enabled the E-liquid to be transferred from the reservoir through the openings to the heater and fluid path. This resulted in a stable and reduced atomization and vaporization.

Optionally, a thickening agent can be used to adjust the viscosity of the e-liquid. Examples of thickening agents are carbomers (more specific sodium carboxy methyl cellulose), agar, gelatin, coconut oil, polysacharides, acacia, alginic acid, bentonite, carboxymethyl cellulose,

ethylcellulose, gelatin, hydroxyethyl cellulose, hydroxypropyl cellulose, magnesium aluminum silicate, methylcellulose, poloxamers, polyvinyl alcohol, sodium alginate, tragacanth, and xanthan gum. The viscosity can be increased such that the E-liquid behaves like a gel. In use it would act like a solid at room temperature and as a liquid at higher temperatures, such as above 50°C.

In use the temperature of the tubular element vastly increases after switching on the system or E-cigarette. After a few seconds, for example about six seconds, at the openings the tubular elements is about 100°C. Therefore, the E-liquid in the direct vicinity of the opening is also increased in temperature such that the viscosity and surface tension decreases enabling transfer of E-liquid from the reservoir through the opening to the heater and fluid path.

The composition preferably comprises glycerol and propylene glycol according to one of the aforementioned ratios. Optionally, as an alternative or in addition thereto, other components can be applied, including painkillers, antibiotics, anti-cancer medicines, vaccines, cardiovascular medicines, anti-infectives, anti-rheumatic medicines, anti-inflammatories, anti-obstipation medicines, anti-asthma medicines, and anti-allergy medicines. This may involve linaclotide, paracetamol, artemisinine, acyclovir, zidovudine, aspirin, for example. Also, other pharmaceuticals and/or nutraceuticals can be applied. An advantage of the present invention is the possibility to evaporate components with relatively high viscosity. In conventional e-cigarettes this is limited due to the use of a wick, for example. Optionally, the size and/or shape of the openings in the cartridge according to the invention can be adapted to the composition.

In a presently preferred embodiment according to the present invention the cartridge further comprises control means such as a flow regulator that are configured for controlling the fluid flow through the openings.

By providing a controlled fluid flow the atomisation and/or vaporisation is better controlled thereby enabling a stable and substantially constant operation. This improves the quality of the entire system. The control means or flow regulator can be provided as an electronic controller controlling the position of one or more valve elements or valves that are blocking an opening at least a part of the one or more openings. This further improves control of the atomisation and/or vaporisation of the E-liquid by the heater. In a presently preferred embodiment the control means or flow regulator comprises a moveable insulating layer or insulating element. For example, this layer or element can be provided as a tubular element that is moveably provided within the main tubular element. When inhaling, fluid is transferred from the reservoir through the openings towards the heater and fluid path. When initiating the inhaling, the moveable element starts to move thereby opening and/or blocking the openings. This enables control of the fluid delivery to the heater and fluid path. Optionally, the valve element involves a so-called bi-metal. When heating the heater, the valve opens or closes depending on the configuration of the valve element.

As a further example of the control means, in use the E-liquid in the opening is heated and evaporates. The evaporated material, such as a gaseous bubble, pushes the E-liquid towards the heater. Optionally, an additional heater is provided to heat the liquid in or close to the openings. This heater may involve an additional conductor and resistor to produce the vapour bubble. This will be explained in relation to one of the illustrated embodiments. The opposite may also be possible, wherein the heating element heats up the liquid in the opening, creates a gas bubble that pushes the liquid back into the reservoir. When the heating element cools, the gas bubble collapses and draws an amount of liquid on the heating element. This amount of liquid is then evaporated the next time the user is taking a puff.

In a further preferred embodiment according to the present invention the cartridge comprises a pump element that is configured for pumping delivery fluid to and through the opening.

The pump element improves the delivery of E-liquid to the heater and thereby a control of the overall process.

In one of the preferred embodiments the pump element comprises a piston element. By providing a piston or piston element in the reservoir the fluid is pushed towards the opening in a controlled manner. The piston can be moved actively by a controller and actuator or passively using spring elements providing a constant pressure to the fluid.

In another preferred embodiment according to the present invention the pump element comprises a pressing element configured for pressing delivery fluid through at least one of the openings. An example of such pressing element the pressing element may use the principles of a thermal inkjet printer by providing an electrical current to a thin film resistor heating up the E- liquid such that it evaporates and pushing the liquid through the opening. By cooling the vapour bubble pressure reduces and a new liquid is transported from the reservoir to the passing element.

The present invention further relates to a personal electronic delivery system, the system comprising:

a cartridge as mentioned earlier;

- an energy assembly having a housing having a first end with an air inlet and a second end with an outlet that in use is connected to the inlet of the cartridge; a fluid path substantially extending between the air inlet and the cartridge outlet. This system provides similar effects and advantages as described above with respect to the cartridge.

In a presently preferred embodiment according to the invention the system 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 according to the invention preferably 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 an embodiment of the invention, 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 also relates to the use of a cartridge and/or personal electronic delivery system as described herein, for delivering the delivery fluid to a person, comprising:

- providing a cartridge and/or system as described earlier in this description;

- inhaling at the second end of the housing to provide a subnormal pressure in the fluid path such that ambient air is sucked into the inlet;

- heating the gas in the reservoir such that in use the temperature of the gas in the reservoir rises with a temperature increase in the range of 1.5 to 7.5 °C and delivery fluid is transferred from the reservoir to the fluid path with the heater; and

- atomizing and/or vaporizing at least a part of the delivery fluid with the heater and delivering at the outlet.

Said use provides the same effects and advantages as described for the system.

The 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, 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 a presently preferred embodiment according to the present invention the delivery fluid that is provided in the reservoir has a composition with a viscosity having a temperature dependency that is adapted to the configuration of the openings in the tubular element such that at a first non-use temperature the fluid is substantially maintained in the housing and that at the second temperature of use the fluid is capable of flowing through the one or more openings. This was explained in relation to the cartridge. This adaptation of number of the design of the openings involving amount, size, shape and characteristics of the E-liquid involving composition, viscosity and temperature dependency thereof, reduces leakage of E-liquid when the cartridge is not in use and improves the transfer or liquid from the reservoir through the openings to the heater and the fluid path when the cartridge is in use. Also, the cartridge according to the invention may use alternative and/or additional components as was mentioned earlier in relation to the cartridge.

The invention further relates to a method for producing a cartridge for a personal electronic delivery system as described earlier, the method comprising the steps of:

- providing a cartridge and/or personal electronic delivery system as described earlier in this description;

- heating the gas in the reservoir such that in use the temperature of the gas in the reservoir rises with a temperature increase in the range of 1.5 to 7.5 °C and delivery fluid is transferred from the reservoir to the fluid path with the heater; and

- atomizing and/or vaporizing at least a port of the delivery fluid.

The same effects and advantages apply to the method as described above with respect to the personal electronic delivery system, the use thereof and the atomizer assembly. 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 oxidation. Plasma 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 μπι, preferably 10-200 μπι, more preferably 50-150 μπι, and most preferably the thickness is about 100 μπι.

In an example of a plasma oxidation process, the thickness of the ceramic layer is controlled by controlling the voltage, the 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 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.

Optionally, the openings may be provided in a groove.

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.

It will be understood that further alternative manufacturing methods could be applied that was mentioned earlier in relation to the cartridge.

Preferably, the metal oxide layer formed by anodizing or plasma oxidation is sealed by a sealing process. In one of the preferred embodiments the metal conductor is made of aluminium or an aluminium alloy, wherein the metal oxide layer is provided by anodizing or plasma oxidation of the conductor, preferably anodizing, after which a sealing process is applied, such as hydrothermal sealing and/or precipitate sealing.

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 A-E shows embodiments of an E-cigarette according to the invention comprising connecting openings;

figure 2 shows an E-cigarette according to the invention;

figure 3 shows a further preferred embodiment of a cartridge or atomizer assembly according to the invention;

figures 4-5 show a further preferred embodiment according to the invention;

figures 6-8 show further alternative embodiments of a cartridge according to the present invention;

figure 9 A-B shows embodiments of a power/current increasing circuit; figure 10 shows an alternative embodiment of an E-cigarette according to the invention;

figure 11 shows a further alternative embodiment of an E-cigarette according to the invention;

figure 12 shows a particle size comparison of aerosols;

figure 13 A-B shows a setup of a plasma oxidation chamber to produce a preferred embodiment of the heater;

figure 14 shows the Voltage as function of time in the manufacturing of the heater in the manufacturing process in the chamber of figure 11 ; and figure 15 shows a heater according to the invention.

E-cigarette 2002 (Figure 1A-B) comprises cartridge housing 2004, inner tube 2006 defining fluid path 2008 extending from first end 2010 to second end 2012 of housing 2004. In the illustrated embodiment heater 2014 is placed in fluid path 2008. Heater 2014 can be provided as element of cartridge housing 2004 or, alternatively, as element of energy assembly 2015

(schematically illustrated in Figure 1A). Assembly 2015 and cartridge 2004 together define E- cigarette 2002 as a personal electronic delivery system with heater 2014 that, 2004 in the illustrated embodiment, is provided in cartridge housing. Container 2016 holds delivery fluid 2018, such as E-liquid and gas 2019, such as air. Inner tube 2006 comprises a number of connecting openings 2020 to enable supply of delivery fluid 2018 from container 2016 to fluid path 2008 with heater 2014. Tube 2006 comprises air flow tube part 2022 and air flow outlet part 2024. In the illustrated embodiment tube part 2022 has an inner diameter of about 2.4 mm and outlet part has an inner diameter of about 2 mm. In use, air is provided through air inlet holes 2026. In the illustrated embodiment holes 2026 have an inner diameter of about 1.1 mm. Via air flow guide part 2028 air is provided to fluid path 2008. In the illustrated embodiment air flow guide part 2028 has an inner diameter of about 1.6 mm. It will be understood that the present invention allows for some variations of the mentioned values and designs.

When activated, heater 2014 provides heat to gas 2019 leading to a temperature increase of gas 2019. Gas 2019 "pushes" an amount of E-liquid 2018 through openings 2020 in fluid path 2008. Heater 2014 atomizes/vaporizes a substantial part of this E-liquid.

In an alternative embodiment, E-cigarette 1002 (Figure 1C) is schematically illustrated and comprises housing 1004, inner tube 1006 defining fluid path 1008 extending from first end 1010 to second end 1012 of housing 1004. Heater 1014 is provided in fluid path 1008. In the illustrated embodiment container 1016 surrounds fluid path 1008. Container 1016 hold delivery fluid 1018, such as E-liquid. Inner tube 1006 comprises a number of connecting openings 1020 to enable supply of delivery fluid 1018 from container 1016 to fluid path 1008 with heater 1014.

In the illustrated embodiment gas room 1021 is provided with an expandable gas. On the other end of container 1016 a further room 1022 is provided in the illustrated embodiment. Gas room 1020 is connected to the delivery fluid chamber with gas pressure element or tube 1024.

Gas, such as air, in gas room 1020 is heated when delivery fluid 1018 needs to be supplied to heater 1014, such as when a user starts inhaling. A battery or other source may provide energy to heater 1014 such that the gas is heated directly or semi-directly. The gas starts to expand and provides a pressure force to delivery fluid 1018. In the illustrated embodiment the pressure force is achieved with the aid of element 1024. It will be understood that also other embodiments to provide a force to delivery fluid 1018 can be envisaged in accordance with the present invention. A small amount of delivery fluid 1018 is pushed through the one or more openings 1020 towards fluid path 1008 and heater 1014. After the user stopped inhaling heater element 1014 is switched of and the gas is allowed to cool off thereby removing the pressure force acting on delivery fluid 1018. In the illustrated embodiment housing 1004 is providing with cooling ribs of fins 1026 to accelerate cooling of the gas.

Assembly 1028 (Figure ID) can be included in E-cigarette 1002 or in another embodiment of such E-cigarette. Assembly 1028 comprises heat transfer guide 1030, such as a tube. First end 1032 of guide 1030 is provided in or close to heater 1014. Second end 1034 of guide 1030 extends in gas room 1021. This enables an effecting heating of the gas in gas room 1020 having a fast response time when inhalation starts.

Another embodiment of the invention that can optionally be applied in combination with one or more of the other embodiments that are described and/or illustrated involves a further modification of inner tube 1006 (Figure IE). In this embodiment inner tube 1006 comprises different parts, for example heat conductive part 1036 to enable effective heat transfer to gas room 1021 and heat insulating part 1038 to reduce heat transfer from heater 1014 to delivery fluid 1018 to prevent temperature changes of delivery fluid 1018 and third part 1040.

It will be understood that other embodiments in accordance with the present invention can be envisaged to provide a pressure force to enable supply of delivery fluid 1018 to fluid path 1008, including mechanical, electromechanical and/or electrical elements, for example. Also, it will be understood that the supply element can be applied to different types of e-cigarettes or other inhaling devices, including the embodiments that will be described next.

E-cigarette 2 (Figure 2) comprises battery assembly 4 and atomizer assembly 6. In the illustrated embodiment atomizer assembly 6 is disposable. It will be understood that the invention can also be applied to systems with other configuration and that the illustrated embodiments is for exemplary purposes only. Details, including connections between parts that are known to the skilled person from conventional E-cigarettes have been omitted from the illustration to reduce the complexity of the drawing.

Battery assembly 4 comprises housing 8, (LED) indicator 10 with air inlet 12, air flow sensor 14, circuit 16 and battery 18. Air from inlet 12 is provided with air path 20 to sensor 14.

Circuit 16 comprises an electronic circuit board that is connected to the relevant components of system 2. Battery 18 can be a rechargeable battery including the required connections to enable recharging. Battery assembly 4 has air inlets 22 and connector 24 to connect battery assembly to atomizer assembly 6.

Atomizer assembly 6 comprises housing 26 with air path 28 that is surrounded with buffer 30 comprising the E-liquid (for example a mixture of glycerol, propylene glycol, nicotine). The buffer may comprise a container. Alternatively or additionally the buffer may comprise a buffer material which may include wicking material such as silica, cotton, etc. or buffer 30 can be provided by other buffer means. In the illustrated embodiment heater element 32 is provided at or around the perimeter of air path 28. In one of the preferred embodiments heater element 32 comprises a wire of metallic titanium core 34 with ceramic titanium oxide layer 36 around metallic core 34. The E-liquid is absorbed and/or adsorbed in the porous ceramic layer. Wire 32 is heated by passing an electric current through metallic titanium core 34. Wire 32 is heated and the E-liquid is evaporated and/or atomized. The mixture is provided to outlet 38 of air path 28 at mouth piece 40.

Heater 32 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 36, such as thickness, size of pores, and porosity.

When inhaling at outlet 38 an under pressure in air paths 20, 28 is achieved. Air is sucked in through inlets 12, 22. Sensor 14 detects an air flow and circuit board 16 sends an indication signal to indicator 10. Battery 18 provides electricity to heater 32 that heats the E-liquid supplied from buffer 30 and vaporizes and/or atomizes the liquid such that a user may inhale the desired components therein.

In the illustrated embodiment heater 28 has its longitudinal axis substantially parallel to air path 28. It will be understood that other configurations are also possible according to the invention.

Optionally, heater 28 is surrounded by buffer 30. The surface area of buffer 30 is preferably provided with (small) openings that are filled with E-liquid from the buffer. Capillary action transfers liquid from the openings to heater element 30. For example, buffer 30 may include a tubular element wherein the openings are provided. A buffer material may or may not be present in the tubular structure. Preferably, such tubular structure is made from metal.

Cartridge or atomizer assembly 102 (Figure 3) comprises housing 104. At end 106 housing 104 and seal 133 is provided with end ring 108 that is preferably pressed in housing 104. End cap 110 is pressed in ring 108. Housing 104 comprises buffer or reservoir 112 and metal tube 114.

Flow path 116 extends through tube 114. Reservoir 112 is positioned around outer surface 118 of tube 114. In the illustrated embodiment inner surface 120 of tube 114 is provided with ceramic layer 122. Ceramic layer 122 is provided over a part of inner surface 120. In particular, openings 126 are provided in a part of tube 114 not provided with a ceramic layer 122. The ceramic layer extends from a position close to the heater to a position close to or at the end of tube 114 facing end 106. Tube 114 further comprises heater element 124. Openings 126 in tube 114 enable transport of fluid from reservoir 112 towards heater element 124. In the illustrated embodiment tube 114 has eight openings 126 with a diameter of about 0.2 mm. It will be understood that other dimensions and shapes can also be envisaged in accordance with the present invention. At end 128 housing 104 is provided with connector 130. Connector 130 with opening(s) 131 comprises seal 132 and screw thread 134. Edge or stop 136 of connector 130 is used for positioning tube 114. In addition, stop 136 prevents leakage of liquid from reservoir 112. In the illustrated embodiment connector 130 is manufactured from brass material. Optionally, connector 130 comprises separate connector part 138 having screw thread 134. Assembly 102 further comprises ring 140 with opening(s) 141. Rubber ring 142 separates connector 130 from metal pin 144. First leg 146 of heater element 124 is connected to pin 144. Second leg 148 of heater element 124 is connected to connector 130 and/or ring 140 thereof.

It will be understood that other configurations of the legs and/or other components can be envisaged in accordance with the present invention, including combining different elements in a single part and/or separating a part into several sub-parts.

In aforementioned preferred embodiments of the system according to the invention, the electronic cigarette comprises two main parts, a first part with a battery with an airflow switch and electronic control equipment for the correct operation of an electronic cigarette, and a second part with a cartridge capable of containing the e-liquid, heating element and parts for the transportation of e-liquid onto the heating element. Cartridge 602 (Figure 4-5) comprises metallic tube 604, in the illustrated embodiments of stainless steel, with eight holes 606 of about 0.25 mm diameter situated about 2.75 mm from the beginning A of the tube that in use is closest to the mouth piece of the electronic cigarette. In the illustrated embodiment tube 604 is about 29.1 mm in length with an outer diameter of about 4 mm and wall thickness of about 0.3 mm. Ceramic tube 608, preferably of zirconium oxide, is provided inside metallic tube 604 at a position about 2.5 mm from openings with a length of about 22 mm, an outer diameter of about 3.4 mm and a wall thickness of about 0.35 mm.

Ceramic coated titanium heating element 610 is placed in the metallic tube 604 with holes 606. Heating element 610 is preferably made of a titanium wire (grade 1) coated with a ceramic layer and wound as a solenoid. The diameter of the titanium wire with the ceramic layer is about 0.25 mm, the total length of the wire used in the heating element is about 90 mm having about ten closely spaced windings 612 with a diameter of about 2.2 mm, and a total length of heating element 610 of about 1.4 mm. Heating element 610 is placed inside metallic tube 604 such that the first windings are positioned in ceramic tube 608 preventing heating element 610 to contact metallic tube 604.

Metallic tube 604 with holes 606 is pressed into a screw cap with connector(s) (not shown) and electrical insulator 618 on side A, and into an end cap (not shown) on the other side. Metallic housing 614, preferably a tube of stainless steel, extends between the screw cap and the end cap, with the tube having a length of about 3.8 mm, diameter of about 9.2 mm and wall thickness of about 0.2 mm. The space, room or compartment 616 between outer metallic tube 614 and inner metallic tube 604 with holes 606 can be filled with e-liquid. For example, the e-liquid comprises about 60% vegetable glycerine, about 30% propylene glycol and about 10% containing nicotine, flavouring and water. The ratio between nicotine, flavouring and water can be adjusted to the preferred amount.

The screw cap of cartridge 602 is connected to the battery of the electronic cigarette thereby connecting the positive and negative poles of the battery to the positive and negative connector of heating element 610. This enables an electric current to flow from the positive pole to the negative pole through the titanium wire to increase the temperature of the titanium wire by joule heating. The electric current is controlled by the flow switch that is activated by the user. For example, a flow sensor detects sucking air and switches the electric current. In use, air flows through metallic tube 604 with holes 606 and e-liquid is transported towards heating element 610. By increasing the temperature of heating element 610, e-liquid evaporates in the air flow and the evaporated e-liquid is transported to the user.

In an alternative embodiment cartridge 620 (Figure 5) is provided with similar components with the exception that holes 606 are provided in groove 622.

It will be understood that components of cartridges 602, 620 can be combined in further embodiments. Cartridges 602, 620 and alternative embodiments can be used in electronic cigarettes 2, and other embodiments thereof.

In a further alternative embodiment cartridge 702 (figure 6) comprises tubular element 703 with a moveable insulating element 704 that is configured for opening and/or blocking opening 705 in tubular element 703. In the illustrated embodiment moveable insulating element 704 is moveable in a direction A that is collinear with the central axis of the tubular element 703. Two abutments for stops 706 limit movement of insulating element 704. Spring element 708 pushes moveable insulating element 704 is a rest position. The rest position in a first embodiment is the blocking position or alternatively in a second embodiment the opening position depending on the configuration of these spring configuration 708. When inhaling the moveable insulating element 704 moves in the direction A to open opening 705, while after inhaling the spring 708 forces the element back to block opening 705.

In a further alternative embodiment 802 (figures 7A-C) tubular element 803 is provided with insulating layer 804 at the opening 805. A valve or valve element 806 opens or blocks opening 805 (figure 7A) e.g. depending on whether the user inhales or activates a switch. In an open position of valve 806 (figure 7B), E-liquid can be transferred from the reservoir to the heater. In a closed position valve element 806 (figure 7C) of opening 805 is closed. This enables controlled transfer of E-liquid from the reservoir to the heater. The valve 806 may comprise a bimetal.

In an even further embodiment 902 according to the invention (figures 8A-B) tubular element 903 is provided with insulating layer 904. In the illustrated embodiment opening 905 are provided with a decreasing diameter in the direction of heater 908. Optionally, (electrical) heating elements 906 are provided in or adjacent to openings 905 (figure 8A). In the illustrated embodiment E-liquid in opening 905 evaporates and the vapour bubble pushes an air bubble towards the heater 908, when cooling opening 905 and its surroundings. The dimensions and shape of opening 905 determines the amount of E-liquid that is transferred to the heater can be controlled effectively (Figure 8B). Alternatively or in addition, the vapour bubble pushes the liquid into the reservoir when heater 908 is heated. When temperature of heater 908 decreased the vapour bubble will collapse and the vacuum/under pressure will provide an amount of liquid to heater 908. This liquid will evaporate the next time heater 908 is heated.

Cartridge 952 (Figure 9) comprises reservoir 954, and tubular element 956 with openings 958. Piston 960 is provided in reservoir 954. Spring element(s) 962 provide pressure to liquid in reservoir 954 pressing liquid through opening 958. Optionally, a controller may activate movement of piston 960 enabling active pressure control, or alternatively spring element(s) 962 push constantly providing a passive pressure control.

Current increasing circuit 402 (Figure 10A) 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 10B) 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.

In a further embodiment of E-cigarette 502 (Figure 11) heater 32 is supplied with energy through connector 504 from super capacitor 506. Capacitor 506 is charged via external connector 508. Capacitor 506 can be charged (semi)-directly and/or indirectly. Such indirect charging can be performed in connection with cigarette box 510 having cigarette storage compartment 512 and battery compartment 514 with battery 516. In a charging state charge connector 518 contacts connector 508 and super capacitor 506 is being charged. In the illustrated embodiment battery 516 is rechargeable through connector 520.

Experiments have been performed with several design of the personal electronic delivery system according to the present invention. Table A shows several of the tested designs.

Table A: Tested designs according to the invention

Results indicated that dosage of E-liquid particularly depends on gas (air) temperature in the reservoir (and therefore not on a so-called venturi -effect). This is confirmed by comparing pressure differences due to an air flow and a temperature rise of the gas. In the tests a temperature rise of about 3 degrees was shown to provide an effective system that was appreciated by its users.

The aforementioned designs according to the invention are tested and compared with the vape of existing electronic cigarettes. The new developed cartridges and systems according to the invention do not contain a wick. Liquid is supplied through the holes of the inner tube to the heating element. Therefore, it offers more possibilities to adjust the liquid to the desired properties. The heating element can be tuned according to the liquid properties. The particle size of in the vape of e-cigarettes has been determined by a CEM DT-9880 particle counter. The vape is measured in the air where it also mixes with the air before measuring. The relative size of the aerosols in different vapes can be compared. This has been done for a conventional electronic cigarette and the for the cartridge and system according to the present invention. Tests have been performed with different E-liquids.

The background of the fraction of particles in the air is included in the figure (bottom line) together with the fraction of particles for a conventional electronic cigarette (second line from bottom). All cigarettes have a high fraction of aerosols smaller than 1 micron, but the new vaporizer according to the invention has a higher fraction of aerosols in the region 1-5 micron (about 2 times higher compared to traditional e-cigarettes) (upper three lines in Figure 12). The amount of particles in the 1-5 micron region increases when the viscosity of the liquid increases (glycerol vg has the highest viscosity). A visual observation during the experiments was that the new vaporizer produces more vape compared to the traditional e-cigarette. The new design has been tested with a so-called wannavape liquid, a mixture of 65% VG with 35% PG, and with glycerol, as seen from third to fifth line from the bottom in Figure 12, respectively).

Results showed that the new design produces more vape (aerosols) (Figure 12). In addition, the design according to the present invention produces relatively more particles in the range of 1 -5 micron (2 times more compared to traditional e-cigarettes), which is beneficial for the uptake in the blood stream through the alveola. This has also been confirmed by vaping tests: a higher nicotine delivery is experienced. Furthermore, the liquid properties for the new heating element can be tuned giving more particles in the 1 - 5 micron range. 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. This is illustrated with the linear relation for NiCr (R=0.0011T+2.164) as compared to the linear relation for Titanium (R=0.0104T+1.5567) defining the linear relation of the measured resistances R at specific temperatures T.

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 13A). Work piece 1104 is connected to the anode 1106. Work piece 1104 is clamped/fixed between two screws or clamps 1108 that are connected to the ground/earth (anode 1104) of a power supply. In the illustrated embodiment cathode 1110 comprises stainless steel honeycomb electrode 1112 that, in use, is placed at close distance above work piece 1104. Electrolyte 1114 flows between electrode 112 and anode 1106, and effectively flows upwards through honeycomb electrode 1112 together with the produced oxygen and hydrogen. Electrolyte effluent 1116, together with the hydrogen and oxygen, is then cooled and optionally returned to chamber 1102. In the illustrated embodiment the temperature of electrolyte 1114 increases from around 11°C entering plasma oxidation chamber 1102 to 25 °C exiting chamber 1102 and is then cooled off using a heat exchanger (not shown).

In the illustrated chamber 1102 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 1106 and cathode 1110 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 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 1102 titanium wire 1202 (Figure 13B) 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/1 NaSi03*5H20 and 15 g/1 (NaP03)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 1302 (Figure 15) according to the invention.

Three experiments were done: 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 14, 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 (μπι) 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

Wire 1: Before plasma electrolytic oxidation (PEO)

L = 0.5 m, D = 0.500 mm, R = 1.2 Ω, Rcalculated = 2.44 Ω/m, Adsorption (water) = 4 μΐ

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 μΐ, 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, p = 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 m3, m = 4.512 e-4 kg, p = 3650 kg/m3, Moxide layer = 2.13 e-5 kg, Voxide layer = 2.56 e-8 m3, Mestimate without porosity = 4.452 e-5 kg, Porosity = 50 %, Calculated adsorption = 12.8 μΐ

It will be understood that for alternative wires other conditions would apply. For example, for a wire having a diameter of 0.1 mm Rcalculated = 61 Ω/m. Such wire with a length of 6.5 cm will give a resistance of 4 Ω. With an oxide thickness of 100 μπι an amount of 1.3 μΐ is adsorbed. 150 μπι gives 3.1 μΐ and 200 μπι gives 5.4 μΐ.

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 μπι thickness was oxidized with a resulting thickness of aluminium oxide of 13 μπι and Table 4 shows the reproducibility of the process. Both tables show voltage, current, temperature of electrolyte going in the plasma oxidation chamber (Tin) and going out the plasma oxidation chamber (Teff) for constant current of 5 A.

Table 3

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

4

0.167 5

34

Table 4

4

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

0.5 47 5

0.16

4 435 5

7

1 61 5

0.5 448 5

4

1 460 5

2 76 5 10.1 18.8

2 474 5 11.3 19.7 4

4 488 5

4 87 5 10.9 20.4

6 495 5

4

8 505 5

6 99 5 11.3 21.4

5

9 15 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 μπι thick aluminium oxide layer. Table 5: Voltage and current ofPEO with Table 6: Voltage and current of pulsed constant current of 2 A. constant current of 1 kHz t min. Voltage V Current A T min. Voltage V Current A

1 380 2 0.1

2 415 2 67 470 5

3 429 2 0.5 485 5

4 437 2 1 491 5

5 443 2 2 502 5

6 448 2 4 514 5

7 452 2 6 523 5

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.

In a further experiment, plasma electrolytic oxidation was used to provide a porous, flexible and elastic ceramic layer of >70 μιη οη titanium foil. Plasma electrolytic oxidation grows a titanium oxide layer which is known to be ceramic (Ti02). Electrolyte was used with 8 g/1 Na2Si03*5H20 (Natrium metasilicate pentahydrate) and 15 g/1 (NaP03)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 μιη. 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

0.167 435 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 M NaN03. 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. 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.

The present invention is by no means limited to the above described preferred

embodiments thereof. The rights sought are defined by the following claims, wherein the scope of which many modifications can be envisaged.