WO2025109365A1

WO2025109365A1 - Switching dual wick vaping system

Info

Publication number: WO2025109365A1
Application number: PCT/IB2023/061880
Authority: WO
Inventors: Mian Sheikh Waseem Amjad; Timothy Wong
Original assignee: 2792684 Ontario Inc
Current assignee: 2792684 Ontario Inc
Priority date: 2023-11-24
Filing date: 2023-11-24
Publication date: 2025-05-30
Anticipated expiration: 2026-05-24

Abstract

As the size of an e-liquid reservoir in a vaping system increases, the lifespan of a wick used to transport the e-liquid becomes of greater importance. To mitigate the effects of using a wick to carry large amounts of e-liquid, a dual atomizer system is provided that automates the switching between the wicks. This can be done on a per-puff basis, or based on time of use, including switching between wicks during a single puff.

Description

Switching Dual Wick vaning system

Cross Reference to Related Applications

[0001] This is the first application for the instant invention.

Technical Field

[0002] This application relates generally to a system for dynamically switching between atomizers, and more particularly to a system for making use of dual atomizers for use in conjunction with an electronic cigarette or vaporizer with a large reservoir of e-liquid.

Background

[0003] Electronic cigarettes and vaporizers are well regarded tools in smoking cessation. In some instances, these devices are also referred to as an electronic nicotine delivery system (ENDS). A nicotine based liquid solution, commonly referred to as e-liquid, often paired with a flavoring, is atomized in the ENDS for inhalation by a user. In some embodiments, e-liquid is stored in a cartridge or pod, which is a removable assembly having a reservoir from which the e-liquid is drawn towards a heating element by capillary action through a wick. In many such ENDS, the pod is removable, disposable, and is sold pre-filled.

[0004] In some ENDS, a refillable tank is provided, and a user can purchase a vaporizable solution with which to fill the tank. This refillable tank is often not removable, and is not intended for replacement. A fillable tank allows the user to control the fill level as desired. Disposable pods are typically designed to carry a fixed amount of vaporizable liquid, and are intended for disposal after consumption of the e-liquid. The ENDS cartridges, unlike the aforementioned tanks, are not typically designed to be refilled. Each cartridge stores a predefined quantity of e-liquid, often in the range of 0.5 to 3 ml. In ENDS systems, the e-liquid is typically composed of a combination of any of vegetable glycerine, propylene glycol, nicotine and flavorings. In systems designed for the delivery of other compounds, different compositions may be used. In some systems designed for the delivery of cannabinoids, different combinations of carriers may be employed, including one or both of vegetable glycerine and propylene glycol.

[0005] In the manufacturing of the disposable cartridge, different techniques are used for different cartridge designs. Typically, the cartridge has a wick that allows e-liquid to be drawn from the e-liquid reservoir to an atomization chamber. In the atomization chamber, a heating element in communication with the wick is heated to encourage aerosolization of the e-liquid. The aerosolized e-liquid can be drawn through a defined air flow passage towards a user’s mouth.

[0006] Figures 1A, IB and 1C provide front, side and bottom views of an exemplary pod 50. Pod 50 is composed of a reservoir 52 having an air flow passage 54, and an end cap assembly 56 that is used to seal an open end of the reservoir 52. End cap assembly has wick feed lines 58 which allow e-liquid stored in reservoir 52 to be provided to a wick (not shown in Figure 1). To ensure that e-liquid stored in reservoir 52 stays in the reservoir and does not seep or leak out, and to ensure that end cap assembly 56 remains in place after assembly, seals 60 can be used to ensure a more secure seating of the end cap assembly 56 in the reservoir 52. In the illustrated embodiment, seals 60 may be implemented through the use of o-rings.

[0007] As noted above, pod 50 includes a wick that is heated to atomize the e-liquid. To provide power to the wick heater, electrical contacts 62 are placed at the bottom of the pod 50. In the illustrated embodiment, the electrical contacts 62 are illustrated as circular. The particular shape of the electrical contacts 62 should be understood to not necessarily germane to the function of the pod 50.

[0008] Because an ENDS device is intended to allow a user to draw or inhale as part of the nicotine delivery path, an air inlet 64 is provided on the bottom of pod 50. Air inlet 64 allows air to flow into a pre-wick air path through end cap assembly 56. The air flow path extends through an atomization chamber and then through post wick air flow passage 54. [0009] Atop pod 50 is a mouthpiece 68, with an absorbent pad 66 between the top of the reservoir 52 and the mouthpiece 68. As post wick airflow passage 54 expands as it gets farther from the end cap 56, droplets of different sizes can be subjected to a sorting process. This can involve the placement of apertures in the mouthpiece 68 which when placed off center result in the airflow path of the droplets entrained in an airflow to bend. This can result in large droplets being prevented from exiting the mouthpiece 68. These droplets, along with others that form from condensation may be absorbed by absorptive pad 66 to prevent their delivery to the user.

[0010] Figure 2 illustrates a cross section taken along line A in Figure IB. This cross section of the device is shown with a complete (non-sectioned) wick 72 and heater 74. End cap assembly 56 resiliently mounts to an end of air flow passage 54 in a manner that allows air inlet 64 to form a complete air path through pod 50. This connection allows airflow from air inlet 64 to connect to the post air flow path through passage 54 through atomization chamber 70. Within atomization chamber 70 is both wick 72 and heater 74. When power is applied to contacts 62, the temperature of the heater increases and allows for the volatilization of e-liquid that is drawn across wick 72.

[0011] Typically the heater 74 reaches temperatures well in excess of the vaporization temperature of the e-liquid. This allows for the rapid creation of a vapor bubble next to the heater 74. As power continues to be applied the vapor bubble increases in size, and reduces the thickness of the bubble wall. At the point at which the vapor pressure exceeds the surface tension the bubble will burst and release a mix of the vapor and the e-liquid that formed the wall of the bubble. The e-liquid is released in the form of aerosolized particles and droplets of varying sizes. These particles are drawn into the air flow and into post wick air flow passage 54 and towards the user.

[0012] User experience of an ENDS is related to a number of factors including the delivery of nicotine and the flavor compounds in the e-liquid. The size of the droplets entrained by the airflow, after the bubble pops, is associated with a number of different experiences. Flavor compounds are best experienced by smaller particle sizes. Larger particles are less likely to impart flavor, and are associated with other negative experiences including an effect referred to as spitback.

[0013] Figure 3 illustrates an alternative embodiment of a pod 50. As in previous embodiments, a reservoir 52 is used to store e-liquid and has a post wick airflow path 54 defined within it. An end cap 56 is used to seal the open end of the reservoir 52. It should be understood that a mouthpiece can be attached to the end of reservoir 52 opposite the end cap 56, but is not shown here. Endcap 56 defines wick feed lines 58 that allow e-liquid from the reservoir 52 to be provided to wick 72. Wick 72 can then draw the e-liquid into atomization chamber 70 where it is atomized by heater 74. Heater 74 can be connected to electrical contacts 62 so that a device can provide power upon activation. The overall airflow path through the pod starts with the pre-wick airflow path 64 and extends to the post wick airflow path 54 after passing through the atomization chamber 70. Where in previous figures, the end cap 56 was secured using O-rings, a resilient sleeve 76 is employed in this embodiment. The resilient sleeve may be formed of a material such as silicone, and may include ribs that help to secure the endcap 56 into the open end of reservoir 52. Resilient sleeve 76 can also provide an interface to allow for the post-wick airflow passage to engage with the atomization chamber 70.

[0014] Those skilled in the art will appreciate that the sealing of the end cap 56 against the reservoir 52 is designed to prevent e-liquid from seeping out of a filled pod 50. To further reduce leakage, the design of pod 50 is often done in conjunction with the design of the e-liquid to be stored within the reservoir. Less viscous e-liquid are often difficult to store as free-liquids within a reservoir 52 because of the difficulties associated with preventing leakage from the pod 50. These less viscous e-liquid are often associated with improved flavor production, so there is a desire to make use of them despite the problems they are associated with.

[0015] Figure 4 illustrates a device 80 making use of a less viscous e-liquid stored within a cartomizer matrix. The device 80 has a reservoir 52 integrated with an electronics portion 88. The reservoir 52 is not used for storage of free e-liquid, and is instead filled with a storage matrix 82, often referred to as a cartomizer matrix 82. This may take the form of a sponge formed of any of a number of different materials including spun nylon based materials. In some embodiments it may be formed through the winding or rolling of materials such as cotton. This matrix 82 is used to store e-liquid, and due to the capillary forces of the matrix 82, a less viscous e-liquid can be stored within device 80 without undue leaking. The wick 72 is supported by airflow channel 84, so that its ends are in fluid engagement with the cartomizer matrix 82. Airflow channel 84 is often implemented as a woven fiberglass tube that has a cut-out sized to support wick 72. Heater 74 typically has leads that are routed through the cartomizer matrix 82, but in some embodiments may be routed through or adjacent to the airflow channel 84. Device 80 makes use of a pressure sensor 90, as a control to a switch. In some embodiments, pressure sensor 90 may be implemented as a pressure switch that closes a circuit upon detecting a change in pressure indicative of a user drawing (inhaling) on the device. The circuit controlled by the pressure sensor 90 includes the heater 74 and the battery 92. Thus, when a user draws on the device, the pressure sensor 90 closes a circuit allowing power from battery 92 to be applied to heater 74. This causes heater 74 to atomize e-liquid drawn across wick 72 from the cartomizer matrix 82 within reservoir 52. [0016] This style of device has become popular as an integrated device 80 that does not make use of replaceable pods. As a disposable device, device 80 is often engineered to remove cost intensive elements like processors or complex control circuitry, but it should be understood that this is done not due to practicality, but instead due to cost constraints. [0017] To suit user demands for a variety of flavors, and to increase the quantity of e-liquid provided to a user in a device, a dual flavor device 86 has been introduced, as illustrated in Figure 5. Device 86 makes use of a single electronics component 88 to support two different, and separated, cartomizer matrices 82a and 82b within reservoir 52. This allows for different flavors of e-liquid to be loaded into each of the cartomizer matrices 82a and 82b. A switch 94 is provided on the exterior of the vaping device that allows the user to select between the heaters 74a and 74b. The other components within the overall device remain consistent. This configuration allows for a single airflow passage 84 to deliver e-liquid vapor, droplets and aerosol from different cartomizer matrices 82a and 82b. One reason for dividing the reservoir 52 between two different matrices 82a and 82b is that a wick often has a lifespan defined by the number of factors. When the wick is used past its lifespan, e-liquid vapor and droplet production can be impacted by off-flavors. Some wicks have been described as imparting an off-flavor akin to a “wet sock”. The different factors that contribute to this sensation are not necessarily germane to this discussion, but it should be understood that this is an undesirable effect. [0018] The cartomizer based devices of Figures 4 and 5 are often produced with the intention of being disposed of after the cartomizer matrix is exhausted of the e-liquid. The less viscous e-liquid is also associated with greater flavor production and a looser draw, that is the pressure required to activate and use the device is quite low. These factors, along with the fact that the cartomizer matrix is known to trap e-liquid that can never be released into the wick, contributes to devices that are often exhausted more quickly than many free-liquid based equivalents. However, as noted above, increasing the capacity of the cartomizer matrix to include more liquid may result in the wick being used past its lifespan, resulting in the production of off-flavors that diminish the user experience. [0019] It would therefore be beneficial to have a mechanism to allow for increased e-liquid capacity in a reservoir without having the wick cause off-flavor generation. Summary

[0020] It is an object of the aspects of the present invention to obviate or mitigate the problems of the above-discussed prior art.

[0021] In a first aspect of the present invention, there is provided a vaping device for atomizing an atomizable liquid. The vaping device comprising a battery, a signal generator and control circuitry. The battery stores power, and in some embodiments is a rechargeable battery. The signal generator can be used to generate a signal having alternating high and low signal levels. The control circuitry switches delivery of power from the battery between a first heater and a second heater. This switching may be done in accordance with the high and low signal levels of the signal generated by the signal generator.

[0022] In an embodiment of the first aspect, the first heater is a part of a first atomizer, the second heater is part of a second atomizer. Each of the first and second atomizers draw e-liquid from a reservoir for atomization. In another embodiment, the control circuitry comprises a pressure sensor for generating a signal indicative of use of the vaping device. Optionally, the signal generated by the signal generator powers the first and second heaters, and the device may further comprise a switch, controlled by the control circuitry in accordance with the output of the pressure sensor, for switching the delivery of power from the battery between the first and second heaters. In another embodiment, each of the first and second heaters has an associated diode connected in series with the respective heater. Optionally, the signal generated by the signal generator has a high signal level above 0V and a low signal level below OV

[0023] In another embodiment, the signal indicative of use is an input to a flip flop acting as the signal generator. Optionally, the flip flop generates an output that alternates between a high voltage level and a low voltage level with each received indication of use. In a further embodiment, the output of the flip flop selects between activation of the first heater and the activation of the second heater. In a further embodiment, the control circuitry optionally comprises a first transistor associated with the first heater and a second transistor associated with the second heater, and where the output of the flip flop is connected to each of the first and second transistors. In a further embodiment, one of the first and second transistor is configured to deliver power to its associated heater when the output of the flip flop is high, and the other of the first and second transistor is configured to deliver power to its associated heater when the output of the flip flop is low. In another embodiment, the control circuitry further comprises a third transistor for controlling the delivery of power to the first and second transistor in accordance with the signal indicative of use generated by the pressure sensor.

[0024] In a further embodiment, each of the first and second transistors is a Metal Oxide Semiconductor Field Effect Transistor (MOSFET). In another embodiment, each of the first, second, and third transistors is a Metal Oxide Semiconductor Field Effect Transistor (MOSFET). Optionally, the third transistor and one of the first and second transistors are integrated in a single integrated circuit.

[0025] In another embodiment, the control circuitry comprises a programmable processor configured to execute instructions stored within an accessible memory. In another embodiment, the atomizable liquid is an e-liquid comprising at least one of vegetable glycerine, propylene glycol, nicotine and a flavorant. In another embodiment, the atomizable liquid comprises a cannabinoid. In a further embodiment, the control circuitry is configured to switch the delivery of power from a first heater to a second heater in accordance with an indicator of a last heater to be activated.

[0026] In a second aspect of the present invention, there is provided a method for execution by a vaping device having first and second heaters. This method comprises receiving an indication of use; activating the first and second heaters; deactivating the first heater; and subsequent to the deactivation of the first heater, deactivating the second heater.

[0027] In an embodiment of the second aspect, receiving the indication of use comprises receiving a signal from a pressure sensor. In another embodiment, deactivating the first heater is performed after a defined time period after the activation of the first and second heaters. In a further embodiment, the defined time period is associated with a timer initiated in response to receiving the indication of use. In another embodiment, updating a heater utilization metric associated with the first heater upon deactivation of the first heater. In another embodiment, deactivating the second heater is performed subsequent to receipt of an indication of an end use. In another embodiment, the indication of the end of use is an end of receiving a signal from a pressure sensor. Brief Description of the Drawings

[0028] Embodiments of the present invention will now be described in further detail by way of example only with reference to the accompanying figure in which:

Figure 1 A is a front view of a prior art pod for use in an electronic nicotine delivery system;

Figure IB is a side view of the pod of Figure 1A;

Figure 1C is a bottom view of the pod of Figure 1 A;

Figure 2 is a cross section of the pod of Figures 1 A and IB along cut line A in Figure IB;

Figure 3 is a cross section view of an alternate embodiment of the pod illustrated in Figures 1 A-C and 2;

Figure 4 is a cross section view of a vaping device having a reservoir with a cartomizer matrix for storing e-liquid;

Figure 5 is a cross section view of a vaping device having dual cartomizer matrices within the reservoir;

Figure 6 is a functional illustration of a device having a pair of atomizers with automated switching between heating elements;

Figure 7 is a block diagram illustrating an embodiment of a vaping device and pod cooperating to provide automated switching between first and second atomizers;

Figure 8 is a circuit diagram illustrating a further embodiment of automated switching between atomizers in a vaping system;

Figure 9 is a cross section view of a vaping device having a pair of atomizers in distinct airflow paths; and

Figure 10 is a flow chart illustrating a method according to one embodiment of the present invention..

[0029] Where possible, in the above figures, like reference numerals have been used for like elements across the figures.

Detailed Description

[0030] In the instant description, and in the accompanying figures, reference to dimensions may be made. These dimensions are provided for the enablement of a single embodiment and should not be considered to be limiting or essential. Disclosure of numerical range should be understood to not be a reference to an absolute value unless otherwise indicated. Use of the terms about or substantively with regard to a number should be understood to be indicative of an acceptable variation of up to ±10% unless otherwise noted.

[0031] To address the desire for larger reservoirs, including those filled with cartomizer matrices, without exhausting a lifespan of a wick, there are a number of different techniques that could be applied. Some of these techniques address design parameters of the wick, seeking to extend the lifespan of the wick. However, changing design parameters of the wick can result in other knock-on effects as the design parameters of the wick already seek to balance the lifespan of the wick with longevity under the repeated heating cycles, cost of material and the rate at which e-liquid can be drawn across the wick. Accordingly, there is a desire to maintain existing wick designs and materials but still address this concern. In furtherance of this desire, it should be understood that the reference to the lifespan of a wick is associated with two different factors, the length of time that a wick is engaged with e-liquid drawn from a reservoir (and possibly the length of time that such a wick is exposed to air), and the quantity of e-liquid drawn across the wick. To some extent, the first factor is difficult to design around, as a manufactured device may spend months making its way through a supply chain before it is purchased and used by an end user. However, it may be possible to control the second factor, that is the volume of e-liquid drawn across the wick during the lifespan of a device.

[0032] Increasing the volume of e-liquid within a cartomizer matrix, or within a free liquid reservoir, addresses a consumer demand for more e-liquid, but it may be possible to mitigate the amount of the e-liquid drawn across the wick by introducing more wicks. Thus, if 75% more e-liquid is provided in a device that has two wicks, neither of the wicks is required to draw additional e-liquid. Furthermore, to offset the amount of time that the wick is saturated with e-liquid and exposed to the environment, it may be possible in some embodiments, to have a lower quantity of e-liquid per wick.

[0033] Requiring a user to manually switch between wicking systems, as shown in Figure 5, provides a poor user experience and it may leave one of the wicks effectively soaking in e-liquid without being used for half the life of the device. This runs a risk that a user will not switch between wicks at the correct time, resulting in use of a wick that has been used to carry too much e-liquid. This may contribute to an off-flavoring. Instead, it would be advantageous to allow for the use of both wicks, though not necessarily simultaneously.

[0034] In the following discussion, reservoirs for the storage of e-liquid will be discussed in the context of being filled with a cartomizer matrix. This should be understood as being for the purposes of discussing example embodiments. The embodiments discussed herein can be implemented, without undue experimentation, in systems that make use of a free-liquid filled reservoir. Figure 6 illustrates a schematic representation of a device 100 according to an embodiment of the present invention. A device 100 makes use of a first heater 106 and a second heater 108. Each of the first and second heaters 106 and 108 are associated with unillustrated wicks that draw e-liquid from the same reservoir. This reservoir may store free e-liquid or it may make use of a cartomizer matrix to store the e-liquid. A pressure sensor 110 (or a pressure switch in some embodiments) detects when a user draws on the device 100, and provides a signal indicative of use to a processor 112. Processor 112 controls a switch that allows power to be delivered from battery 114 to one of the heaters 106, 108. Whereas conventional devices have used a pressure sensor to control activation of a heater, in the illustrated embodiment, the switch 116 can be controlled to engage with any one of the first heater 106, the second heater 108 or no heater. This three state switch can also be implemented as two switches, one that switches between heaters 106 and 108 and the other that switches between on and off.

[0035] During use, the processor 112 can control switch 116 to alternate between heater 106 and heater 108. This allows both wicks to be used, and allows time for each wick to draw e-liquid across from the reservoir towards the heater. The switching between heaters 106 and 108 also reduces the duration of heating that each wick is exposed to which may aid in avoiding burning or other heat related deterioration of the wick.

[0036] In some embodiments, the processor 112 can be replaced with any of a variety of different switching control circuits, as will be discussed in further detail in conjunction with the following figures.

[0037] Figure 7 illustrates an embodiment of device 100 in which signal generator 118 and a pair of diodes 124, 126 are used to replicate the functionality of the switch in the embodiment of Figure 6. It should also be noted that device 100 in Figure 7 may be a device that makes use of a detachable pod 102 and a reusable device 104. The interface between pod 102 and device 104 is a set of electrodes 120 in device 104 and electrical contacts 122 in pod 102. When a user draws on device 100, pressure sensor 110 will detect the change in pressure and will provide a signal indicative of use to the processor 112. The processor 112 (or other substitute control circuitry) will control signal generator 118 to produce a signal having a mean voltage of 0, and having positive and negative voltage peaks. Signal generator 118 receives power from battery 114 and transmits the generated voltage signal towards the heaters through electrodes 120. As the voltage varies between a positive and negative peak, the voltage differential between contacts 122 will change from a positive to a negative value. Diode 124 is paired with heater 106, and will only allow current to flow through the heater 104 in one direction. Similarly, diode 126 is paired with heater 108 and only allows current to flow through heater 108 in the opposite direction. Thus, when a varying voltage having positive and negative peaks, such as a square wave centered on a zero voltage value, is generated by signal generator 118, each of the heater coils will be activated in alternate time windows. The period of the generated signal can be tuned to allow for each of heating coils 106 and 108 to be used for periods of time long enough to generate sufficient e-liquid vapor, but not so long that the wick will dry out. Thus, the period of the signal can be selected to allow for device and e-liquid specific parameters, including the amount of time that it takes a wick to exhaust or replenish the e-liquid drawn from the reservoir, and the amount of time that a wick should be heated to release a suitable amount of e-liquid vapor.

[0038] By alternating between the heaters 106, 108 device 100 is able to use a larger e-liquid reservoir without exceeding the life cycle of the wicks. Additionally, each of the wicks can be provided with time to re-wick the atomized e-liquid so that the likelihood of damaging the wick during use is diminished. In some embodiments, processor 112 can be replaced by control circuitry which may integrate pressure sensor 110 as a pressure switch which activates the signal generator 118 in response to the detection of use of the device. [0039] It should be understood that although the signal generator 118 of the illustrated embodiment generates a signal with both positive and negative voltage levels, it should be understood that a signal that is only positive or only negative could also be used. In such an embodiment, different circuitry could be used to switch between the heater 106 and heater 108 at a given voltage level. In such embodiments because one heater is being powered with a higher voltage than the other heater, it may be desirable to have different resistances associated with each heater.

[0040] Those skilled in the art will appreciate that many different circuits can be designed using different components to arrive at the same, or a similar, effect. Figure 8 illustrates one such alternative design. In this design, a D-flip flop and a number of MOSFETs are used. The D-flip flop toggles its output between a high state and a low state, alternating on a per-puff basis (based on input form the pressure sensor). This allows the D-flip flop to function as a signal generator, the output of which is used to control which MOSFET is activated, and thus which heater is powered. In this way, the control circuitry illustrated in Figure 8 alternates which heater is activated on a per-use basis. A pressure sensor 110 within the device 104 detects changes in pressure associated with the use of the device 100. The output of the pressure sensor 110 is used as one of the inputs to IC2 130, a D-flip flop. Between successive activations of the pressure sensor 110, IC2 130 will change between a high and low level signal. IC2 130 can be thought of as a logic controller that provides an output voltage level on a signal line Q that can be used as an input to two power mosfets QI 132 and Q2 134. Alternatively, IC2 130 can be seen as generating a control signal that is used to select between activation of a heater connected to QI 132 and a heater connected to Q2 134. A variety of different elements could be used in the implementation of this function, including a CMOS digital Integrated circuit such as a TC7W74FU or TC7W74FK made by Toshiba™ Corp. It should be understood that Q2 134 can be better understood as operating as two MOSFETs. Both QI 132 and Q2 134 receive signal Q from IC2 130. They also both receive power VBAT from the battery. The second MOSFET function from Q2 134 is used to toggle the activation of either Q2 132 or the primary MOSFET function of Q2 134 in accordance with the activation signal from the pressure sensor 110. Thus, when pressure sensor 110 is activated, it provides an indication of use to IC2 130, and to Q2 134. IC2 130 generates a signal on output line Q that determines which heater should be activated. The secondary MOSFET function of Q2 134 then controls delivery of power from either QI 132 or Q2 134 to the heaters 106 and 108 based on whether it is receiving a signal from pressure sensor 110 indicating use. When pressure sensor 110 no longer detects use, the secondary MOSFET function of Q2 prevents power from being delivered from the last activated MOSFET. In this configuration, an alternating high and low voltage level on signal line Q allows for the alternating heating of the two heating elements on a per puff basis. [0041] As noted earlier, the circuit of Figure 8 should be understood to be an example of a particular implementation and should not be considered to be limiting the manner in which a vaping device can be implemented. It should be understood that the use of metal oxide semiconductor field effect transistors (MOSFET) as illustrated in Figure 8 is optional, and in other embodiments other types of transistors may be used. In the illustrated embodiment, both P-type and N-Type MOSFETs are used, but again this design choice should not be considered as limiting as other designs could also be elected. Where specific integrated circuits are illustrated in use, it should be noted that other components could be used with the required modifications that would be understood by those skilled in the art.

[0042] Those skilled in the art will appreciate to address a number of issues, including the possible facilitation of a larger e-liquid reservoir, two different heater and wick systems can be provided in a pod, or in an integrated device. Each of these heaters can be activated separately, and in some embodiments, they cannot be activated together. Using either control circuitry, or control processes carried out in a processor, power can be alternated between the first and second heaters. This ensures that over the course of the lifespan of a disposable device (or over the lifespan of a replaceable pod), neither of the wicks is used for more e-liquid than a lifespan of the wick. This alternation may be done on a time-based allocation, a general round-robin alternation, a per-puff alternation in which each wick is used for the duration of a single puff. Any reasonable way of alternating between the wicks can be supported in different embodiments. As noted above, some embodiments, such as a time based alternation, may lend themselves to implementations in dedicated circuitry, while other embodiments may more appropriately lend themselves to implementation using a programmable processor. Nonetheless, the controlled alternating of application of power to the first and second heaters allows two different wicking systems to share a common reservoir of e-liquid. In other embodiments, the two wicking systems may access different reservoirs of e-liquid. This can allow for two different cartomizers to be used to store the same e-liquid. In other embodiments, different e-liquids may be stored in different cartomizers. This could be done to generate different flavor combinations, or to have a single flavor paired with a flavorless e-liquid to produce a less pronounced flavoring. In some embodiments, a flavored e-liquid without nicotine or a cannabinoid could be stored in a first section of the reservoir, while a flavorless e-liquid with at least one of nicotine and a cannabinoid can be stored in the other section of the reservoir. There are many different variations that can be implemented for any number of reasons.

[0043] The device makes use of a switching system, responsive to use of the device to control which heater the power from the battery is directed towards. The system alternates between the heater according to a defined pattern. In vaping systems with replaceable pods, this may take the form of a pod with two electrical contacts designed to selectively deliver power to a heater based on a characteristic of the current or voltage applied (e.g. the direction of the current, or the voltage level). In other embodiments, the pod may have different electrical contacts associated with each heater, which may take the form of at least three contacts associated with the heater (assuming that the two heaters share a ground or return connection), and in some embodiments may involve four contacts. It should be understood that the activation can alternate during a single use of the device, or the alternation between the first and second heaters may be done on a per-use basis, so that during one use the first heater is activated, and during the next use the second heater is activated.

[0044] Those skilled in the art will appreciate that, as shown in Figure 9, in some embodiments, device 200 has a reservoir 202 and two airflow passages 204, 208. Each airflow passage 204, 208 has an atomizer 206, 210 respectively. In some embodiments atomizers 206, 210 are heaters that are supplied e-liquid from the reservoir 202 through a wicking system. Heaters 206 and 210 are powered by battery 212. Controller 214, which may be implemented as control routines programmed into a processor, controls switch 216 so that power can be delivered to each of the heaters independently. It should be understood that in the illustrated embodiment, switch 216 has four positions. The first position does not provide power to the heaters. This is effectively an off position. In the second position, power is delivered to heater 206. In the third position, power is delivered to heater 210. In a third position, power is delivered to both heaters 210 and 206.

[0045] This configuration allows for the heaters 210 and 206 to be activated together or separately. Figure 10 is a flow chart illustrating an exemplary method 220 of operating a device. This method 220, or variations thereof, may be implemented as instructions that can be executed by a processor or other such set of control circuitry to control two heaters, referred to as heater A and heater B. In step 222 a puff is detected. This may be carried out by a user actuating a button or switch to indicate an intention to use the vaping device 100, 200, or it may be through a signal provided by a pressure sensor. A timer is activated in step 222, and heaters A and B are activated in step 224. The activation of both heaters is continued until in step 226 it is determined that the timer has expired. [0046] Upon expiry of the time (or after a defined time period has elapsed) one of the heaters is deactivated in step 228. In some embodiments, the heater that is deactivated in one cycle is the heater that was not deactivated in the previous cycle. In some embodiments, a heater activation time can be tracked (as either an absolute value or as a differential value), and the deactivation of a heater in step 228 may include deactivating the heater with a higher utilization value in step 230. In step 232, the utilization metric for the deactivated heater can be updated and stored in step 232.

[0047] Power is delivered to the active heater until step 234 when a signal is received indicating that power to the heater should be discontinued. In some embodiments this corresponds to the detection of the end of the puff (e.g. the user is no longer pressing an activation button, or the pressure sensor no longer detects a user puff). In other embodiments, this may correspond to a timeout value that is associated with an activation, which may be designed to prevent overheating of components. Subsequently, the active heater is deactivated in step 236, and optionally, the heater utilization metric for the active heater can be updated in step 238. The process 220 can end at step 240.

[0048] This method 220, or variations thereof, allows for activation of both heaters, and then leaves one of the heaters active after deactivation of one of the heaters. This can provide a vaping experience that is more satisfactory to some users, while still providing the alternating heating discussed in earlier embodiments.

[0049] Although presented above in the context of use in an electronic nicotine delivery system such as an electronic cigarette (e-cig) or a vaporizer (vape) it should be understood that the scope of protection need not be limited to this space, and instead is delimited by the scope of the claims. Embodiments of the present invention are anticipated to be applicable in areas other than ENDS, including (but not limited to) other vaporizing applications. [0050] In the instant description, and in the accompanying figures, reference to dimensions may be made. These dimensions are provided for the enablement of a single embodiment and should not be considered to be limiting or essential. The sizes and dimensions provided in the drawings are provided for exemplary purposes and should not be considered limiting of the scope of the invention, which is defined solely in the claims.

Claims

1. A vaping device for atomizing an atomizable liquid, the vaping device comprising: a battery for storing power; a signal generator for generating a signal having alternating high and low signal levels; and control circuitry for switching delivery of power from the battery between a first heater and a second heater in accordance with the high and low signal levels of the signal generated by the signal generator.

2. The vaping device of claim 1 wherein the first heater is a part of a first atomizer, the second heater is part of a second atomizer, and wherein each of the first and second atomizers draw e-liquid from a reservoir for atomization.

3. The vaping device of any one of claims 1 and 2 wherein the control circuitry comprises a pressure sensor for generating a signal indicative of use of the vaping device.

4. The vaping device of claim 3 wherein the signal generated by the signal generator powers the first and second heaters.

5. The vaping device of claim 4 further comprising a switch, controlled by the control circuitry in accordance with the output of the pressure sensor, for switching the delivery of power from the battery between the first and second heaters.

6. The vaping device of any one of claims 4 and 5 wherein each of the first and second heaters has an associated diode connected in series with the respective heater.

7. The vaping device of claim 6 wherein the signal generated by the signal generator has a high signal level above OV and a low signal level below OV.

8. The vaping device of any one of claims 3 to 7 wherein the signal indicative of use is an input to a flip flop acting as the signal generator.

9. The vaping device of claim 8 wherein the flip flop generates an output that alternates between a high voltage level and a low voltage level with each received indication of use.

10. The vaping device of any one of claims 8 and 9 wherein the output of the flip flop selects between activation of the first heater and the activation of the second heater.

11. The vaping device of claim 10 wherein the control circuitry further comprises a first transistor associated with the first heater and a second transistor associated with the second heater, and where the output of the flip flop is connected to each of the first and second transistors.

12. The vaping device of claim 11 wherein one of the first and second transistor is configured to deliver power to its associated heater when the output of the flip flop is high, and the other of the first and second transistor is configured to deliver power to its associated heater when the output of the flip flop is low.

13. The vaping device of any one of claims 11 and 12 wherein the control circuitry further comprises a third transistor for controlling the delivery of power to the first and second transistor in accordance with the signal indicative of use generated by the pressure sensor.

14. The vaping device of any one of claims 11 to 13 wherein each of the first and second transistors is a Metal Oxide Semiconductor Field Effect Transistor (MOSFET).

15. The vaping device of claim 13 wherein each of the first, second, and third transistors is a Metal Oxide Semiconductor Field Effect Transistor (MOSFET).

16. The vaping device of claim 15 wherein the third transistor and one of the first and second transistors are integrated in a single integrated circuit.

17. The vaping device of any one of claims 1 to 16 wherein the control circuitry comprises a programmable processor configured to execute instructions stored within an accessible memory.

18. The vaping device of any one of claims 1 to 17 wherein the atomizable liquid is an e-liquid comprising at least one of vegetable glycerine, propylene glycol, nicotine and a flavorant.

19. The vaping device of any one of claims 1 to 18 wherein the atomizable liquid comprises a cannabinoid.

20. The vaping device of any one of claims 1 to 19 wherein the control circuitry is configured to switch the delivery of power from a first heater to a second heater in accordance with an indicator of a last heater to be activated.

21. A method for execution by a vaping device having first and second heaters, the method comprising: receiving an indication of use; activating the first and second heaters; deactivating the first heater; and subsequent to the deactivation of the first heater, deactivating the second heater.

22. The method of claim 21 wherein receiving the indication of use comprises receiving a signal from a pressure sensor.

23. The method of any one of claims 21 and 22 wherein deactivating the first heater is performed after a defined time period after the activation of the first and second heaters.

24. The method of claim 23 wherein the defined time period is associated with a timer initiated in response to receiving the indication of use.

25. The method of any one of claims 21 to 24 further comprising updating a heater utilization metric associated with the first heater upon deactivation of the first heater.

26. The method of any one of claims 21 to 25 wherein deactivating the second heater is performed subsequent to receipt of an indication of an end use.

27. The method of claim 26 wherein the indication of the end of use is an end of receiving a signal from a pressure sensor.