BR122023019691B1 - DEVICE FOR CONTROLLING ELECTRICAL POWER SUPPLY AND AEROSOL SUPPLY SYSTEM - Google Patents

Abstract

A device for controlling the delivery of electrical power in response to air pressure measurement includes an air flow path, a chamber having an opening, a liquid flow limiter configured to inhibit the entry of liquid into the chamber through the opening, a pressure sensor located in the chamber and operable to detect, in the presence of the liquid flow limiter, air pressure changes caused by airflow in the airflow path, and a circuit for converting the detected air pressure changes by the pressure sensor to control signals to control the power output of a battery.

Description

[0001] This request is divided from BR 11 2019 005634 3, of September 11, 2017.

Technical Field

[0002] The present invention relates to devices for controlling the supply of electrical energy in response to air pressure measurement, for example, for use in aerosol delivery systems.

Background

[0003] Aerosol delivery systems, such as electronic cigarettes, generally contain a reservoir of a source liquid containing a formulation, typically including nicotine, from which an aerosol is generated, such as through vaporization or other means. Thus, an aerosol source for an aerosol delivery system may comprise a heating element coupled to a portion of the reservoir source liquid. When a user inhales into the device, the heating element is activated to vaporize a small amount of the source liquid, which is thus converted into an aerosol for inhalation by the user. More particularly, such devices are normally provided with one or more air inlet holes located away from a nozzle of the system. When a user sucks on the mouthpiece, air is drawn through the inlet holes and passes through the aerosol source. There is an airflow path that connects the inlet ports to the aerosol source and an opening in the nozzle so that air drawn past the aerosol source continues along the flow path to the nozzle opening, carrying some of the aerosol from the aerosol source with it. Aerosol-carrying air exits the aerosol delivery system through the mouthpiece opening for inhalation by the user.

[0004] To enable “on-demand” delivery of aerosol, in some systems, the airflow path is also in communication with an air pressure sensor. Inhalation by the user through the airflow path causes a drop in air pressure. This is detected by the sensor, and an output signal from the sensor is used to generate a control signal to activate a battery housed in the aerosol delivery system to provide electrical power to the heating element. Thus, the aerosol is formed by vaporization of the source liquid in response to inhalation by the user through the device. At the end of the puff, the air pressure changes again, to be detected by the sensor so that a control signal to stop the supply of electrical energy is produced. In this way, the aerosol is generated only when required by the user.

[0005] In such a configuration, the airflow path communicates with both the pressure sensor and the heating element, which is itself in fluid communication with the source liquid reservoir. Therefore, there is a possibility that the source liquid may find its way to the pressure sensor, for example, if the electronic cigarette is dropped, damaged or mishandled. Exposing the pressure sensor to liquid may prevent the sensor from functioning properly, temporarily or permanently.

[0006] Therefore, approaches to mitigate this problem are of interest.

summary

[0007] According to a first aspect of certain embodiments described herein, there is provided a device for controlling the supply of electrical energy in response to measuring air pressure, the device comprising: an air flow path; a chamber with an opening; a liquid flow limiter configured to inhibit liquid from entering the chamber through the opening; a pressure sensor located in the chamber and operable to detect, in the presence of the liquid flow limiter, air pressure changes caused by airflow in the airflow path; and a circuit for converting air pressure changes detected by the pressure sensor to control signals for controlling power output from a battery.

[0008] The pressure sensor may be operable to detect, in the presence of the liquid flow limiter, an air pressure change in the range of 155 Pa at an air flow in the air flow path of 5 ml per second at 1400 Pa an airflow in the airflow path of 40 ml per second.

[0009] The airflow path may be outside the chamber and in communication with the opening. With the exception of the opening, the chamber can be airtight.

[0010] Alternatively, the opening is an air outlet for the chamber, the chamber further comprises an air inlet, and the airflow path passes through the chamber and includes the opening and the air inlet.

[0011] The liquid flow limiter may be disposed in or through the opening, or in or through the airflow path, or may be the opening itself if appropriately sized.

[0012] The liquid flow limiter may comprise a mesh, for example, a mesh that has a surface layer of hydrophobic material or is made from hydrophobic material, and/or a mesh with a pore size of 100 μm or less and a caliber of 200 or greater.

[0013] In other embodiments, the liquid flow limiter may comprise a nozzle with an orifice. The nozzle may be made from or have a surface coating of hydrophobic material. For example, the nozzle may be made of polyether ether ketone. Alternatively, the nozzle may be hydrophilic. For example, the nozzle may be made of metal, such as stainless steel. The nozzle orifice may have a diameter of 0.5 mm or less, such as 0.3 mm.

[0014] In other embodiments, the liquid flow limiter may comprise a one-way valve configured to open under the pressure of the air flow in the air flow path in a first direction and be closed against the liquid flow in an opposite direction.

[0015] The device may further comprise a battery that reacts to control signals from the circuit. The device may be a component of an aerosol delivery system.

[0016] In accordance with a second aspect of certain embodiments provided herein, there is provided an aerosol delivery system comprising a device for controlling the supply of electrical energy in response to measuring air pressure in accordance with the first aspect.

[0017] According to a third aspect of certain embodiments provided herein, there is provided a device for controlling the supply of electrical energy in response to measuring air pressure, the device comprising: an air flow path; a chamber; an opening that opens from the airflow path into the chamber; a liquid flow limiter disposed in or through the opening and configured to inhibit the entry of liquid into the chamber through the opening, the liquid flow limiter comprising a mesh or a nozzle with an orifice; a pressure sensor located in the chamber and operable to detect, in the presence of the liquid flow limiter, air pressure changes caused by airflow in the airflow path; and a circuit for converting air pressure changes detected by the pressure sensor to control signals for controlling power output from a battery.

[0018] According to a fourth aspect of certain embodiments provided herein, there is provided a device for controlling the supply of electrical energy in response to measuring air pressure, the device comprising: an air flow path; a chamber; an opening that opens from the airflow path into the chamber; a liquid flow restrictor disposed in or through the opening and configured to be air permeable and liquid impermeable so as to inhibit the entry of liquid into the chamber; a pressure sensor located in the chamber and operable to detect, in the presence of the liquid flow limiter, air pressure changes caused by airflow in the airflow path; and a circuit for converting air pressure changes detected by the pressure sensor to control signals for controlling power output from a battery.

[0019] These and other aspects of certain embodiments are presented in the attached independent and dependent claims. It should be noted that features of the dependent claims may be combined with each other and features of the independent claims in combinations other than those explicitly set out in the claims. Furthermore, the approach described herein is not restricted to specific embodiments, as set forth below, but includes and contemplates any appropriate combinations of features set forth herein. For example, a device may be provided in accordance with the approaches described herein, which includes any one or more of the various features described below, as appropriate.

Brief Description of the Drawings

[0020] Various embodiments will now be described in detail, by way of example only, with reference to the attached drawings, in which:

[0021] Figure 1 shows a schematic representation of an aerosol delivery system in which embodiments of the invention can be used;

[0022] Figure 2 shows a schematic cross-sectional representation of part of an aerosol delivery system in which embodiments of the invention can be used;

[0023] Figure 3 shows a first example of a device configuration according to embodiments of the invention;

[0024] Figure 4 shows a second example configuration of a device according to embodiments of the invention;

[0025] Figure 5 shows a third example of a device configuration according to embodiments of the invention;

[0026] Figure 6 shows graphs of pressure measurements recorded using a mesh embodiment of a liquid flow limiter in a flow-through configuration;

[0027] Figure 7 shows graphs of pressure measurements recorded using a mesh embodiment of a liquid flow limiter in a flow diversion configuration;

[0028] Figure 8 shows a cross-sectional perspective view of an exemplary device according to a mesh embodiment of a liquid flow limiter;

[0029] Figure 9 shows a graph of the pressure measurements recorded from the device of Figure 8 before and after the leak test;

[0030] Figure 10 shows graphs of pressure measurements recorded using a nozzle embodiment of a liquid flow limiter in a flow diversion configuration;

[0031] Figure 11 shows a perspective cross-sectional view of an example device according to a nozzle embodiment of a liquid flow limiter;

[0032] Figure 12 shows graphs of pressure measurements recorded from the device of Figure 8 with different nozzles;

[0033] Figure 13 shows a graph of the pressure measurements recorded from the device of Figure 11 before and after the leak test; It is

[0034] Figure 14 shows a schematic cross-sectional representation of an example device, according to a valve embodiment of a liquid flow limiter.

Detailed Description

[0035] Aspects and characteristics of certain examples and embodiments are discussed/described here. Some aspects and features of certain examples and embodiments may be conventionally implemented and these are not discussed/described in detail for the sake of brevity. It will thus be understood that aspects and features of apparatus and methods discussed herein which are not described in detail may be implemented in accordance with any conventional techniques for implementing such aspects and features.

[0036] As described above, the present disclosure relates to (but is not limited to) aerosol delivery systems, such as electronic cigarettes. Throughout the following description, the term “e-cigarette” may sometimes be used; however, it should be noted that this term may be used interchangeably with aerosol (steam) delivery system.

[0037] Figure 1 is a highly schematic diagram (not to scale) of an aerosol/vapor delivery system such as an electronic cigarette 10 to which some embodiments are applicable. The electronic cigarette has a generally cylindrical shape, extending along a longitudinal axis indicated by dashed line, and comprises two main components, namely, a body 20 and a cartridge assembly 30.

[0038] The cartridge assembly 30 includes a reservoir 38 containing a source liquid comprising a liquid formulation from which an aerosol is generated, e.g., containing nicotine, and a heating element or heater 40 for heating the source liquid to generate the aerosol. The source liquid and heating element 40 may be collectively referred to as an aerosol source. The cartridge assembly 30 further includes a mouthpiece 35 having an opening through which a user can inhale the aerosol generated by the heating element 40. The source liquid may comprise about 1 to 3% nicotine and 50% glycerol, with the remainder comprising approximately equal measures of water and propylene glycol, and possibly also comprising other components, such as flavorings. The body 20 includes a rechargeable cell or battery 54 (referred to hereinafter as a battery) for providing power to the electronic cigarette 10, and a printed circuit board (PCB) 28 and/or other electronic components for generally controlling the electronic cigarette. In use, when the heating element 40 receives power from the battery 54, as controlled by the circuit board 28 in response to pressure changes detected by an air pressure sensor (not shown), the heating element 40 vaporizes the source liquid. in the heating location to generate the aerosol, and this is then inhaled by a user through the opening in the mouthpiece 35. The aerosol is transported from the aerosol source to the mouthpiece 35 along an air channel (not shown) that connects the aerosol source to the mouthpiece opening as the user inhales into the mouthpiece.

[0039] In this particular example, the body 20 and the cartridge assembly 30 are detachable from each other by separation in a direction parallel to the longitudinal axis, as shown in Figure 1, but are joined together when the device 10 is in use by engaging elements. cooperators 21, 31 (e.g., a screw or bayonet fitting) to provide mechanical and electrical connectivity between the body 20 and the cartridge assembly 30. An electrical connector interface on the body 20 used to connect to the cartridge assembly 30 may also serve as an interface for connecting the body 20 to a charging device (not shown) when the body 20 is detached from the cartridge assembly 30. The other end of the charging device may be connected to an external power source, e.g. a USB socket, for charging or recharging the battery 54 in the body 20 of the electronic cigarette. In other implementations, a separate charging interface may be provided, for example, so that the battery 54 can be charged while still connected to the cartridge assembly 30.

[0040] The electronic cigarette 10 is provided with one or more holes (not shown in Figure 1) for air intake, the inward air flow is generally shown by arrows 36. These holes, which are on an outer wall of the body 20 , connect to an airflow path through the electronic cigarette 10 to the mouthpiece 35. The airflow path includes a pressure sensing region (not shown in Figure 1) in the body 20 and then connects from the body 20 to the cartridge assembly 30 to a region around the heating element 40 such that when a user inhales through the mouthpiece 35, air is drawn into the airflow path through one or more air intake holes. This airflow (or the resulting change in pressure) is detected by a pressure sensor (not shown in Figure 1) in communication with the airflow path which, in turn, activates the heating element (through operation of circuit board 28) to vaporize a portion of the source liquid to generate the aerosol. The air flow passes through the air flow path, and combines with the vapor in the region around the heating element 40, and the resulting aerosol (combination of the air flow and condensed vapor) travels along the air flow path. airflow connecting from the heating element region 40 to the mouthpiece 35 to be inhaled by a user, the outward airflow (into the user's mouth) is shown at 37.

[0041] In some examples, the detachable cartridge assembly 30 may be discarded when the source liquid supply is exhausted, and replaced with another cartridge assembly, if so desired. The body 20, however, may be intended to be reusable, for example, to provide operation for a year or more by connecting to a series of disposable cartridge sets. Therefore, it is of interest that the functionality of the components in the body 20 is preserved.

[0042] Figure 2 shows a schematic longitudinal cross-sectional view through a central part of an example electronic cigarette similar to that in Figure 1, where the cartridge assembly 30 and the body 20 come together. In this illustration, the cartridge assembly 30 is shown attached to the body 20; the side walls 32, 22 of these components being shaped to permit a press fit (push fit, bayonet or screw fits may also be used). The side wall 22 of the body 24 has a pair of holes 24 (more or fewer holes may be used) that allow air to enter, shown by arrows A. The holes connect to a first part of an airflow path center or channel 66 located in the body 20, which is connected to a second part of the airflow channel 66 located in the cartridge assembly 30 when the cartridge assembly 30 and the body 20 are connected, to form an airflow channel continuous 66. The heating element 40 is located within the air flow channel 66 so that air can be drawn through it to collect the vaporized source liquid when a user inhales through the nozzle to draw air through the holes 24.

[0043] The body 20 also includes a pressure sensor 62 operable to detect changes in air pressure within the airflow channel 66. The sensor 62 is in a chamber 60 that connects to the first part of the airflow path 66 through an opening 64. Changes in air pressure in channel 66 are communicated to chamber 60 through opening 64 for detection by sensor 62. In alternative arrangements, sensor 62 may be located within the air flow channel (discussed further below ). The circuit board 28 or other previously mentioned electronic is also located in the chamber 60 in this example (it may be located elsewhere in the electronic cigarette) and receives the output from the sensor 62 when responding to the change in air pressure. If an air pressure drop that exceeds a predetermined threshold is detected, this indicates that a user is inhaling through the airflow channel, and the circuit board generates a control signal to the battery 54 to supply electrical current to produce heating of the heating element. These various components can be thought of as a device for controlling the supply of electrical power in response to air pressure measurement.

[0044] The heating element 40 receives a supply of source liquid from the electronic cigarette reservoir (not shown in Figure 2), for example, through capillarity (depending on the structure of the material of the heating element). As can be seen from Figure 2, this brings the source liquid closer to the pressure sensor. Under normal operating conditions this will generally not be problematic; the heating element is capable of retaining the source liquid, and the source liquid is regularly removed from the area as it is vaporized. However, a leak, rupture, or other failure of the reservoir, an impact to the electronic cigarette, or similar incident, may force or allow the source liquid to travel along the airflow channel 66 past the heating element 40 in a direction opposite to the inhalation direction of the air flow, as indicated by arrow L. Liquid may then be able to enter chamber 60 and disrupt the operation of pressure sensor 62.

[0045] Embodiments of the invention refer to arrangements intended to inhibit exposure of the pressure sensor to the source liquid, while still allowing acceptable operation of the pressure sensor. Various configurations are considered.

Device geometries

[0046] Figure 3 shows a highly schematic representation (not to scale) of a first example of an air pressure sensing arrangement in accordance with embodiments of the invention. The arrangement is similar to that shown in Figure 2. No significance is attached to the orientation of the features as variously illustrated. In the example of Figure 3, the pressure sensor 62 is located in a chamber 60 adjacent to part of the airflow path or channel 66, which is defined by the side walls formed within the structure of the electronic cigarette and in communication with the airflow holes. air inlet described previously. The canal may or may not be straight as it passes through the chamber. Upon inhalation by a user, air flows along the path as indicated by arrow A. The chamber 60 has an opening 64 in a wall that opens into the air flow path 66, the air flow path being outside the chamber. and not flowing through it. Changes in air pressure occurring in the airflow path are communicated to the interior of the chamber 60 through the opening 64, so that the pressure sensor 62 is able to detect the changes and send a corresponding output to the control electronics or circuit board (not shown in Figure 3). In accordance with embodiments of the invention, the device further includes a liquid flow limiter 70 (also referred to as a limiter) positioned in, over or through the opening 64 which acts to prevent, reduce or inhibit any liquid L that may be in the path of air flow 66 from entering chamber 60 and compromising sensor 62. Various configurations of liquid flow limiter 70 are contemplated; these are described further below. However, the common properties of the configurations are that each device is permeable to airflow in that pressure changes in the airflow path 66 are fully or largely communicated in chamber 60 for successful detection by sensor 66. while also being completely or significantly impermeable to the flow of liquid so that the entry of liquid into the chamber 60 and the proximity of the sensor 66 is inhibited or prevented. To this end, in this example, the liquid flow limiter 70 will typically be sized and shaped to fill the opening 64, whether inserted into the opening or fixed over the opening 64. In the particular arrangement of the example of Figure 3, the operation of the flow limiter Liquid flow 70 is facilitated if the chamber 60 is substantially airtight, with the exception of the opening. This creates a backpressure from the chamber 60 compared to the pressure in the airflow channel during an inhalation that acts against the flow of any liquid at or near the restrictor 70 into the chamber 60. Furthermore, the arrangement of Figure 3 keeps the airflow channel in a clear and unrestricted condition so that the user's experience of inhaling through the electronic cigarette is unaffected. Airflow A bypasses limiter 70. Additionally, the example configuration of Figure 3 provides an alternative and easier flow path for any liquid that finds the path along the airflow path as the opening. Liquid is more easily able to continue along the airflow path past the opening than it is to penetrate the stopper and enter the chamber, so this is the more likely outcome, and liquid is kept out of the chamber by this mechanism as well. .

[0047] Figure 4 shows a highly schematic representation (not to scale) of a second example air pressure sensing arrangement in accordance with embodiments of the invention. The chamber 60, sensor 62, opening 64, and airflow path 66 are arranged as in the example of Figure 3, with the airflow path 66 external to the chamber 60. In this example, however, the liquid flow limiter 70 is located in and extends through the airflow path 66, rather than the opening 64. It is located downstream of the opening taking into account the direction of inhalation air flow A, but upstream of the opening taking into account the direction of possible liquid flow L. Thus, the air pressure in the air flow path 66 is communicated directly to the chamber 60 and to the sensor 62 through the opening without any hindrance, while the liquid is inhibited or prevented from reaching the opening by the presence of stopper 70. As before, stopper 70 is permeable to airflow so that air can pass freely along the airflow path 66. Note that in this example, however, stopper 70 is directly in airflow A along path 66; it is in a flow-through configuration, in contrast to the flow-bypass configuration of Figure 3. The presence of the limiter may therefore be apparent to a user inhaling through the e-cigarette, e.g. inhalation required to activate the device may increase. The limiter can be designed to solve this problem, as discussed below.

[0048] Figure 5 shows a highly schematic representation (not to scale) of a third example of an air pressure sensing arrangement in accordance with embodiments of the invention. This example has similarities to the example of Figure 4 in that it is a through-flow arrangement, where air flow A passes through restrictor 70. In contrast to the examples of Figure 3 and Figure 4, however, the path of airflow 66 is arranged to pass through chamber 60. Chamber 60 has an opening 64 as before, but in this example opening 64 is an outlet or opening from chamber 60 for airflow path 66. Chamber 60 has an additional opening 68, being an inlet to chamber 60 for airflow path 66. During inhalation by the user, airflow A enters chamber 60 through inlet 68 and exits through outlet opening 64. Pressure sensor 62 is located in chamber 60 as before, but the configuration of Figure 5 exposes sensor 62 more directly to the air flow and resulting pressure changes. Chamber 60 is illustrated as a box substantially wider than the inlet and outlet portions of the airflow path; this is not necessary. A path enlargement just sufficient to accommodate the volume of the sensor can be used instead, or the sensor can be located directly in the airflow path so that the path acts as the chamber. The chamber can be shaped to facilitate smooth airflow through it. In this example, the liquid flow limiter 70 is positioned in or through the opening 64 at the air outlet of the chamber. This location is upstream of the sensor 62 taking into account the direction of possible liquid flow L, so that the sensor 62 is protected from exposure to liquid by the liquid flow inhibiting character of the limiter 70. The limiter 70 is preferably configured for minimal impact on the airflow passing through it so that its presence is not easily detectable by the inhaler user.

[0049] Although the examples in Figures 3, 4 and 5 differ in the relative positioning of components and features, it should be noted that in each case the limiter is arranged to keep fluid from the sensor by inhibiting the entry of liquid into the chamber through of an opening in the chamber, although it will not prevent the sensor from functioning.

[0050] Three liquid flow limiter designs will now be described. Respectively, these are a mesh limiter, a nozzle limiter and a valve limiter.

Mesh limiter

[0051] A mesh sheet can be employed as a liquid flow limiter in the present context. The openings or pores between the warp and weft of the mesh allow air to flow, but if the openings are small enough, the passage of liquid can be greatly impeded due to the surface tension in the liquid. The liquid will not be able to form droplets small enough to pass through the openings. The mesh can be considered as a membrane permeable to gas (including air) but impermeable to liquid. Liquid impermeability can be increased if the mesh is provided with a surface layer of a hydrophobic material, or manufactured from a hydrophobic material. An appropriately sized and/or treated sheet of mesh may be affixed in place to fully or substantially cover the chamber opening 64 (Figures 3 and 5) or extend wholly or substantially through the airflow channel orifice 66 (example of Figure 4, or example of Figure 5 in a location further upstream than described).

[0052] Possible mesh materials include stainless steel and polymer (such as nylon). Tests of various fine meshes were carried out. In each case, the mesh was formed from a regular set of fibers or threads interwoven in a square grid pattern. Different wire thicknesses and different gauges (giving different pore sizes) were tested, including 80-gauge stainless steel mesh (pore size about 280 μm, wire thickness about 150 μm); 200 gauge stainless steel mesh (pore size about 64 μm, wire thickness about 30 μm); 400 gauge stainless steel mesh (pore size about 37 μm, wire thickness about 27 μm); 500 gauge stainless steel mesh (pore size about 22 μm, wire thickness about 28 μm); and fine nylon mesh (pore size about 162 μm, wire thickness about 53 μm). Samples of each mesh type were treated with a hydrophobic spray application treatment, an example of a commercially available product being NeverWet (RTM) from Rust-Oleum (RTM) which repels surface liquid. Vapor deposition is an application technique for hydrophobic treatment. Furthermore, the selection of a suitable hydrophobic material must be made taking into account the intended purpose of the device. Inclusion in an aerosol delivery system intended for oral use by humans would require the hydrophobic material to be tested or certified for use in the food and/or medical industry.

[0053] The meshes were tested on test equipment with pass-through and bypass flow configurations, with airflow pass-through and chamber geometries comparable to those found in real electronic cigarettes. A vacuum pump was used to generate airflow through the test equipment, monitored with a flow meter and pressure gauge. To mimic the flow conditions inside a real e-cigarette device, an air flow of 50 ml/s was produced with a total pressure drop of approximately 1.3 kPa. The airflow was run for a period of approximately 3 seconds.

[0054] The test equipment included two pressure sensors, one on each side of the mesh, to measure the pressure drop across the mesh. Measurements can be evaluated to determine whether the presence of the mesh adversely affects the pressure change in the chamber such that a measurement taken in the chamber would not correctly reflect airflow during an inhalation, and whether the presence of the mesh is greatly interfering with the airflow through the device.

[0055] Figure 6 shows experimental results from the test equipment for a flow-through configuration, as graphs of the measured differential pressure. Lines A are from a sensor on the upstream side of the loop and lines B are from a sensor on the downstream side of the loop. The data is normalized over the atmospheric pressure value, so only the differential pressure relative to the atmosphere is shown. Figure 6(a) shows measurements from a control test, with a 2 mm diameter opening and no mesh. This result indicates a pressure drop of about 0.1 kPa across the opening at a flow rate of 50 ml/s. Figure 6(b) shows measurements from a test of a 5 mm diameter opening covered with the hydrophobic coated 80 gauge steel mesh. A similar pressure drop of about 0.1 kPa is observed, indicating that the presence of the mesh does not affect the airflow and pressure behavior. In contrast, for smaller gauge meshes, the pressure drop required to maintain a flow rate of 50 ml/s becomes much greater. Figure 6(c) shows measurements for 200 gauge steel mesh with hydrophobic coating (5 mm diameter), which indicates a pressure drop of about 0.7 kPa, and Figure 6(d) shows measurements for 400 gauge steel mesh with hydrophobic coating (5 mm diameter) and indicate a pressure drop of about 6 kPa. The finer meshes are therefore contributing high airflow resistance, which would likely be considered high suction resistance in a real aerosol delivery system.

[0056] It may be that the high strength of the finer meshes was in part caused by clogging of the pores by the applied hydrophobic spray coating. For some applications this may not be problematic. Otherwise, it is possible to adopt a coating process that applies a thinner layer of hydrophobic material, or omit the hydrophobic material, or increase the diameter of the opening and the mesh covering it (options for this will depend on the desired geometry of the device), or use mesh with larger pores if it can still provide adequate restriction to liquid flow.

[0057] Figure 7 shows the experimental results of the test equipment for a flow diversion configuration with a mesh limiter. In this arrangement, a first sensor was in an enclosed chamber behind a mesh-covered opening, and a second sensor was in the main airflow passage. The first sensor therefore measures the pressure drop across the passage as experienced by the loop. Figure 7(a) shows measurements from a control test, with an opening of 10 mm and no mesh. Measurements from both sensors are plotted, but they are substantially overlapping, indicating the same pressure inside and outside the chamber, with little or no decrease in magnitude or time delay. Similar results are observed for a 10 mm diameter 500 gauge steel mesh (without hydrophobic coating) and for a 10 mm diameter polymer mesh (without hydrophobic coating), shown in Figures 7(b) and 7(c ), respectively. These results indicate that a pressure sensor in a separate chamber communicating through an opening with the airflow path and protected by a mesh over the opening is capable of accurately detecting pressure changes in the flow path and the mesh. does not interfere with air flow. An advantage of this geometry (corresponding to the example in Figure 3) is that, because the limiting device, in the form of a mesh, is not placed in the airflow path, a much finer mesh can be used without any increase in airflow resistance. suction compared to a pass-through flow geometry. A finer mesh will likely be more effective in resisting liquid flow and therefore preventing liquid from entering the chamber, and may provide adequate protection without a hydrophobic coating.

[0058] The various meshes, with and without hydrophobic coating, were further tested to evaluate their ability to resist liquid infiltration through them. Using tubes closed at a lower end with a disc of each type of mesh, several infiltration tests were carried out, of increasing rigor. The liquid used was a nicotine solution for use in electronic cigarettes. The untreated polymer mesh and untreated 80-gauge steel mesh withstood a drop of added liquid plus minor agitation without infiltration. Adding more drops caused seepage. When treated with a hydrophobic coating, these meshes were initially able to withstand five more drops, but showed infiltration after a 10-minute delay. This also applies to all larger gauge steel meshes when hydrophobic treatment is lacking. When receiving a hydrophobic coating, the 200, 400 and 500 gauge steel meshes did not show infiltration after the 10 minute delay, but allowed the liquid to pass when subjected to a positive pressure of 1.3 kPa, which was able to push the liquid through the mesh pores. This applied pressure corresponds to a user actively blowing into an e-cigarette (as opposed to the usual sucking, inhaling action), which may be done in an attempt to clear a perceived blockage. This blockage could be a source liquid leak from the reservoir, so blowing on the e-cigarette could propel the liquid through any mesh barriers placed along the airflow path. In this context, therefore, a flow diversion geometry, such as the example in Figure 3, may be preferred. The results of other tests are relevant to this.

[0059] Figure 8 shows a cross-sectional perspective view through additional test equipment 80, designed to more accurately model parts of an electronic cigarette, and utilizing a mesh limiter in a flow diversion configuration, as may be noted by a comparison with Figure 2. A chamber 60 has mounted on its upper inner surface a pressure sensor 62. The upper wall of the chamber 60 is illustrated with a hole; this was used in tests concerning air leaks and air tightness, but was closed for the current example to provide an airtight chamber. The chamber 60 has an opening with a diameter of 4 mm in a wall, which is covered by a mesh limiter 70a. The mesh in this example was a 5 mm diameter disc of 500 gauge stainless steel with a hydrophobic surface coating, glued over the opening. An airflow path 66 passes through the opening so that the interior of the chamber is in air communication with the airflow path 66 through the mesh 70a. The path is formed by a first tube 66a arranged vertically to simulate the air intake through the hole 24 in the body of an electronic cigarette, and a second tube 66b arranged horizontally to simulate the airflow channel leading to the heating element in the cartridge assembly of an electronic cigarette, but, in the test equipment 80, terminating in an outlet 25. The two tubes join at a right angle in the vicinity of the mesh 70a and the opening.

[0060] To simulate a leak and an attempt to unlock it by a user, the test equipment 80 was rotated to position the tube 66b vertically, and this tube 66b was flooded with nicotine solution (the same liquid used in the infiltration tests ). This equates to an extreme leak caused by complete failure of the cartridge assembly. Positive pressure was applied to outlet 25 to imitate a user puffing on a blocked electronic cigarette; this propelled the nicotine solution along the tube 66a and out through the air inlet 24. Next, pressure measurements were recorded during a 3 second air flow at 50 ml/s (as before) and compared with measurements under the same conditions taken before the leak simulation.

[0061] Figure 9 shows a graph of these measurements, normalized to atmospheric pressure as before. Line A and line B are respectively the pressure signal recorded before and after the leak simulation. As can be seen, the two recorded pressure profiles are very similar, indicating that the mesh was successful in protecting the sensor from the liquid in this bypass arrangement (which provides an alternative path for the liquid, rather than it being forced through the mesh), and also that any residual liquid in and around the mesh does not adversely affect the pressure transferred to the chamber and detected by the sensor.

[0062] For the particular application of an aerosol delivery system, such as an electronic cigarette, the results indicate that a mesh with a pore size of about 25 μm or less at a gauge of about 500 would be effective. Larger pores and gauges may also be considered suitable for this application, such as a pore size of less than 100 μm, less than 75 μm, or less than 50 μm, in a 200 or 400 gauge. For other applications, meshes of other dimensions may be preferred.

nozzle limiter

[0063] A second example of a liquid flow limiter that may be employed is a nozzle, or tube, by which is meant an element that has a narrow, possibly cylindrical, orifice passing through it. The orifice can be straight, which reduces the impact of the presence of the nozzle on transmitting the air pressure change through the limiter to the sensor. Furthermore, the orifice may have a constant or substantially constant diameter, width and/or cross-sectional area. When placed in an opening or air flow path as in the configurations of Figures 3, 4 and 5, the nozzle has the effect of reducing or narrowing the width or diameter of the opening or path to the width of the orifice. Alternatively, the opening or path may be formed with a narrow diameter (the orifice) at the appropriate point to avoid the need for a separate component. Air can still pass through the hole, but the passage of liquid will be quite restricted; surface tension will prevent the liquid-forming droplets from being small enough to pass through the hole. Any positive pressure on the far side of the nozzle, for example from within a sealed chamber, will also resist liquid flow. Thus, a barrier is formed that is permeable to air but impermeable or almost impermeable to liquid, which can be placed to protect the sensor from exposure to liquid. In the context of a pass-through flow geometry (Figures 4 and 5, for example), the nozzle may restrict airflow too much for a particular application, although it can sometimes be useful. In this case, a nozzle may be more usefully employed in a flow diversion geometry, such as the configuration in Figure 3.

[0064] Several nozzles were tested on a bypass flow test rig similar to that used in the mesh test, with a first sensor located within a narrow orifice chamber as an opening and a second sensor located in a flow path. air outside the chamber. As before, a vacuum pump was applied to the equipment for periods of about three seconds, producing a flow rate of about 50 ml/s.

[0065] Figure 10 shows the results of these tests, according to graphs of the measurements recorded by the two sensors, normalized to atmospheric pressure as before. Lines A are from the sensor in the chamber and therefore behind the nozzle, and lines B are from the sensor in the airflow path. Figure 8(a) shows measurements for a 1.2mm internal diameter hole or hole, Figure 8(b) shows measurements for a 0.51mm internal diameter hole or hole, Figure 8(c) shows measurements for a 0.26 mm internal diameter hole or orifice and Figure 8(d) shows measurements for a 0.21 mm internal diameter hole or orifice. Evaluation of these results reveals how much of the external pressure (airflow in the airflow path) is transmitted through the nozzle orifice and detected by the sensor in the chamber (lines A). For the larger 1.2 mm nozzle, approximately 90% of the external signal is detected. The proportion of signal detected inside the chamber decreases with decreasing nozzle orifice, until with the 0.21 mm nozzle only about 10% of the external airflow pressure is detected. This is not entirely as expected; the reduction in signal is greater than expected. A likely explanation is that there were imperfections in the manufacture and assembly of the equipment such that the chamber containing the sensor was not completely sealed against the external atmosphere. As the size of the nozzle decreases, the effect of any leakage becomes proportionally greater and produces equalization of the pressure in the chamber to the atmosphere; This will mask a low pressure signal generated by the airflow on the other side of the nozzle (in the airflow path). Ensuring a good seal against atmospheric pressure for a chamber housing a sensor and protected by a small diameter nozzle will overcome this. This also applies to embodiments using a mesh limiter instead of a nozzle limiter. High-quality manufacturing and testing to achieve a sealed chamber can provide greater measured signals from inside the chamber and therefore more reliable device operation. Other tests verified this.

[0066] Figure 11 shows a perspective view of the cross section through another test rig constructed to test nozzle limiters. The equipment 82 is of the same construction as the mesh test equipment 80 shown in Figure 8, with the exception that the mesh limiter 70a is replaced by a nozzle limiter 70b. Several nozzles were tested, each filling the opening with chamber 60. The nozzles had internal orifice diameters of 0.5 mm, 0.25 mm and 0.125 mm. Other inner diameters can be used, such as 0.4mm, 0.3mm, 0.2mm and 0.1mm. The nozzles were made from polyether ether ketone (PEEK), which is an inherently hydrophobic material. Other hydrophobic materials can also be used to manufacture nozzles for limiter applications. Metals can also be used to manufacture the nozzle, such as stainless steel. Furthermore, the chamber can be formed with an integrated nozzle. For example, the chamber may be formed with an opening that is suitably sized to function as a nozzle limiter. The chamber was sealed to make it airtight to the nozzle orifice. During the test, air was sucked through the airflow path 66 at a rate of 50 ml/s for about 3 seconds using a vacuum pump.

[0067] Figure 12 shows the results of these tests, according to graphs of the pressure recorded by sensor 62, normalized to atmospheric pressure. Figure 12(a) shows the measurement of a control test in which no nozzle 70b was used, the opening open to the chamber 62 having a diameter of 2 mm. Figures 12(b), 12(c) and 12(d) show, respectively, the results for nozzle holes of 0.25 mm, 0.5 mm and 0.125 mm. These results show that for a chamber sealed against air leaks, the nozzles do not attenuate the pressure signal that can be recorded by the sensor in the chamber, even for the smallest diameter nozzle orifice that will provide the greatest protection against liquid ingress. . An accurate measurement of the pressure in the airflow passage can be made by the sensor in the chamber.

[0068] In contrast, additional tests carried out with air leaks deliberately introduced into the chamber showed a much reduced pressure signal compared to those in a sealed chamber. The effect is greater for a larger leak compared to the nozzle orifice size; for example, a leak from a 0.25 mm orifice reduced the magnitude of the signal recorded with a 0.125 mm nozzle by about 95%, but reduced the magnitude of the signal recorded with a 0.5 mm nozzle by about 20%. %. A leak comparable to or greater than the inlet to the chamber is capable of equalizing or nearly equalizing the chamber to atmospheric pressure, so that little of the airflow pressure can be detected in the chamber. A smaller leak allows only partial equalization, so a greater proportion of the airflow pressure can be measured in the chamber. In conclusion, a chamber properly sealed for airtightness ensures that the maximum amount of pressure signal can be detected in the chamber.

[0069] The ability of the nozzle stops to resist liquid infiltration was also tested. Holes with diameters ranging from 0.5 mm to 2.0 mm were drilled into the Perspex sheet (RTM). A first set of holes was closed at the end, that is, it did not pass through the sheet. A second set of holes was also closed, and the surrounding sheet material was treated with a spray coating of hydrophobic material (NeverWet (RTM)). A third and fourth set of holes were opened at the end, that is, passed through the sheet, in untreated and treated material, respectively. Liquid in the form of nicotine solution for electronic cigarettes was deposited into each hole, and the degree of Penetration into the hole was observed.

[0070] Closed holes without hydrophobic treatment showed little penetration, with more for larger diameter holes. Open holes without hydrophobic treatment showed penetration of all holes. Surface treatment has greatly improved the performance of the holes. For the open holes, the larger diameter holes showed penetration, but the hydrophobic material was able to resist liquid penetration into the narrower holes. For the closed holes, only the largest showed any liquid penetration, and that was only partial. The hydrophobic material causes the liquid to force into a bead or droplet, whose surface tension prevents it from flowing into the hole. More energy would be required to overcome this and force the liquid into the orifice so that the energy balance is tilted against liquid entry. The effect will be improved if the inner surface of the hole also has a hydrophobic surface. Although a more elaborate surface coating can be used to achieve this, an alternative is to make a nozzle stopper from an inherently hydrophobic material, such as the PEEK nozzles discussed above.

[0071] Furthermore, closed holes were much more effective in preventing liquid entry than open holes. This is because the liquid acts to seal a volume of air at the bottom of the hole, and as the liquid tries to penetrate further into the hole, this air is compressed and creates back pressure to resist the liquid, balancing the weight of the liquid to prevent more entry. This effect is absent in an open orifice where no air is trapped. In the context of protecting a sensor inside a chamber, closed and open holes are similar to an airtight chamber and a leaky chamber. The volume of the chamber will be larger than the volume of the test holes, however, less back pressure will be generated and the shielding effect may be reduced. It will still provide some effect, however, so it is beneficial to attempt an airtight seal of a used chamber with a nozzle limiter.

[0072] Additional infiltration tests were performed using the nozzle test equipment 82 shown in Figure 11. The nozzle orifice diameter was 0.25 mm and the nozzle was made from PEEK. A leak simulation test protocol as described in relation to Figures 8 and 9 was applied.

[0073] Figure 13 shows the results of this test. Lines A and B respectively show the pressure detected in the chamber before and after the leak simulation. The pressure recorded is very similar for each test, indicating no damage to the sensor from liquid inlet, and no effect on sensor performance from any residual liquid remaining on, around, or in the nozzle after pouring.

[0074] For the particular application of an aerosol delivery system, such as an electronic cigarette, the results indicate that a nozzle with an orifice width of about 0.5 mm or less will be effective, including 0.3 mm or less , 0.25 mm or less and 0.125 mm or less. For other applications, nozzles of other sizes may be preferred.

valve limiter

[0075] Alternatively, a valve can be used as a liquid flow limiter. A one-way valve, configured to open and allow flow (of gas or liquid) in one direction but remain closed to block flow in an opposite direction, can be positioned in the airflow path to allow air to pass through in the inhalation inlet direction (from the inlet holes 24 to the mouthpiece 35 in Figure 1), but to block the flow of liquid in the opposite direction (from the reservoir 38 and the heating element 40 towards the chamber 60 and air inlets 24 in Figure 1). If placed downstream of the sensor relative to the airflow direction and upstream of the sensor relative to the liquid flow direction, any leaking liquid will be prevented from reaching the sensor while still allowing the sensor to detect the airflow and detect corresponding pressure changes.

[0076] In such an arrangement, one can consider the “break pressure”, which is the amount of incident airflow pressure that is required to open the valve. The device on which the liquid flow limiter is to be used may have an operating pressure corresponding to the air flow during normal operation of the device, and if the breakdown pressure exceeds this operating pressure, the device may become inoperable or more difficult to use. For example, in an electronic cigarette, the airflow generated by a user's inhalation produces the operating pressure. Typically, this is on the order of 155 Pa to 1400 Pa at an air flow rate of 5 to 40 ml/s. If a valve with an opening pressure above this is installed in the airflow path, the user will have to inhale with more force to get the valve to open, which may be considered undesirable. The valve will also take up space in the airflow path, providing resistance to airflow so that when open, greater pressure may be required to generate the desired flow rate than if the valve were absent. Furthermore, if the valve has an obvious step change in its operating characteristics, such that it is closed below the breakdown pressure and almost or fully open immediately after the breakdown pressure is exceeded, an undesirable effect visible to the user may be produced. A valve that opens more gradually with increasing pressure may be preferred, to avoid noticeable burst pressure.

[0077] Any type of one-way valve of a suitable size and operating characteristic for a particular device and its intended use can be employed as a liquid flow limiter in the context of embodiments of the invention. For example, a spring valve or a duckbill valve can be used.

[0078] Figure 14 shows a schematic cross-sectional representation of part of an electronic cigarette equipped with a valve, such as a duckbill valve, similar to the device shown in Figure 2. Air enters through one or more holes 24 on the side of the device and flows along an airflow path 66 to a heating element 40. A chamber 60 houses a sensor 62 for detecting pressure changes in the airflow path 66 through an opening 64. Subsequent to opening, relative to the air flow direction A, a one-way valve 70c is fitted in the air flow path 66, in front of the heating element 40. Under the action of sufficient air inlet pressure, the valve 70c opens to allow the air in the heating element 40. Without air flow, the valve 70c remains closed, and prevents or inhibits the flow of liquid L from the heating element 40 to the chamber 60.

[0079] Each of the various embodiments of the liquid flow limiter can be used in the example configurations of Figures 3, 4 and 5, or similar configurations of chamber, sensor, airflow path and limiter arranged to have the same function or similar function. Furthermore, two or more limiters may be employed together to enhance the effect of protecting the sensor from exposure to liquid. For example, a single device may include a mesh and a nozzle. Two stops may be situated in a common location with the airflow path, such as both in the opening in a device of Figure 3 to provide a combined bypass flow arrangement, or both in the airflow path in a device of Figure 4 to provide a combined flow-through arrangement. Alternatively, they may be separated with one in a flow diversion position and one in a flow passage position.

[0080] The various embodiments described here are presented solely to help understand and teach the claimed features. These embodiments are provided as a representative sample of embodiments only and are not exhaustive and/or exclusive. It should be understood that the advantages, embodiments, examples, functions, characteristics, structures and/or other aspects described herein should not be considered limitations on the scope of the invention as defined by the claims or limitations in equivalents of the claims, and that other embodiments may be used. and modifications may be made without departing from the scope of the claimed invention. Various embodiments of the invention may suitably comprise, consist of, or consist essentially of appropriate combinations of the elements, components, features, parts, steps, means, etc., other than those specifically described herein. Additionally, this disclosure may include other inventions not currently claimed but which may be claimed in the future.

Claims (15)

1. Device for controlling the supply of electrical energy in response to air pressure measurement comprising: an air flow path (66); a chamber (60) having an opening (64); a liquid flow limiter (70) configured to inhibit liquid from entering the chamber through the opening; a pressure sensor (62) located in the chamber and operable to detect, in the presence of the liquid flow limiter, air pressure changes caused by air flow in the air flow path; and a circuit (28) for converting air pressure changes detected by the pressure sensor to control signals for controlling the power output of a battery (54) characterized by the fact that the liquid flow limiter comprises a mesh (70a ). 2. Device according to claim 1 characterized by the fact that the pressure sensor is operable to detect, in the presence of the liquid flow limiter, an air pressure change in the range of 155 Pa at an air flow in the trajectory from airflow of 5 ml per second at 1400 Pa to an airflow in the airflow path of 40 ml per second. 3. Device according to claim 1 or 2 characterized by the fact that the opening opens from the air flow path to the chamber. 4. Device according to any one of claims 1 to 3 characterized by the fact that the air flow path is outside the chamber and is in communication with the opening. 5. Device according to claim 4 characterized by the fact that, with the exception of the opening, the chamber is airtight. 6. Device according to any one of claims 1 to 3 characterized by the fact that the opening is an air outlet for the chamber, the chamber further comprises an air inlet (68), and the air flow path passes through of the chamber and includes the opening and air inlet. 7. Device according to any one of claims 1 to 6 characterized by the fact that the liquid flow limiter is disposed in or through the opening. 8. Device according to any one of claims 1 to 6 characterized by the fact that the liquid flow limiter is disposed in or through the air flow path. 9. Device according to any one of claims 1 to 8 characterized in that the mesh has a surface layer of hydrophobic material or is made of hydrophobic material. 10. Device according to any one of claims 1 to 9 characterized by the fact that the mesh has a pore size of 100 μm or less. 11. Device according to any one of claims 1 to 10 characterized by the fact that the mesh is configured to be air permeable and liquid impermeable. 12. Device according to any one of claims 1 to 11 characterized in that the mesh is formed from stainless steel or from a polymer. 13. Device according to any one of claims 1 to 12 characterized by the fact that it further comprises a battery that responds to control signals from the circuit. 14. Device according to any one of claims 1 to 13 characterized by the fact that the device is a component of an aerosol delivery system. 15. Aerosol delivery system (10) characterized by the fact that it comprises a device for controlling the supply of electrical energy in response to air pressure measurement as defined in any one of claims 1 to 14.