The present invention relates to a device, system and method for the delivery of aerosols. In particular, but not exclusively, one or more embodiments in accordance with the present invention relate to the delivery of aerosols comprising different active components.
Nicotine replacement therapies are aimed at people who wish to stop smoking and overcome their dependence on nicotine. One form of nicotine replacement therapy is an inhaler or inhalator. These generally have the appearance of a plastic cigarette and are used by people who crave the behaviour associated with consumption of combustible tobacco—the so-called hand-to-mouth aspect—of smoking tobacco. An inhalator comprises a replaceable nicotine cartridge. When a user inhales through the device, nicotine is atomised or aerosolised from the cartridge and is absorbed through the mucous membranes in the mouth and throat, rather than travelling into the lungs. Nicotine replacement therapies are generally classified as medicinal products and are regulated under the Human Medicines Regulations in the United Kingdom.
In addition to passive nicotine delivery devices such as the Inhalator, active nicotine delivery devices exist in the form of electronic cigarettes. The inhaled aerosol mist or vapour typically bears nicotine and/or flavourings. In use, the user may experience a similar satisfaction and physical sensation to those experienced from combustible tobacco products, and exhales an aerosol mist or vapour of similar appearance to the smoke exhaled when using such combustible tobacco products.
A smoking-substitute device generally uses heat and/or ultrasonic agitation to vaporize/aerosolise a solution comprising nicotine and/or other flavouring, propylene glycol and/or glycerol formulation into an aerosol, mist, or vapour for inhalation. A person of ordinary skill in the art will appreciate that the term “smoking-substitute device” as used herein includes, but is not limited to, electronic nicotine delivery systems (ENDS), electronic cigarettes, e-cigarettes, e-cigs, vaping cigarettes, pipes, cigars, cigarillos, vaporizers and devices of a similar nature that function to produce an aerosol mist or vapour that is inhaled by a user. Some electronic cigarettes are disposable; others are reusable, with replaceable and refillable parts.
Smoking-substitute devices may resemble a traditional cigarette and are cylindrical in form with a mouthpiece at one end through which the user can draw the aerosol, mist or vapour for inhalation. These devices usually share several common components; a power source such as a battery, a reservoir for holding the liquid to be vaporized (often termed an e-liquid), a vaporization component such as a heater for atomizing, aerosolising and/or vaporizing the liquid and to thereby produce an aerosol, mist or vapour, and control circuitry operable to actuate the vaporization component responsive to an actuation signal from a switch operative by a user or configured to detect when the user draws air through the mouthpiece by inhaling.
The popularity and use of smoking-substitute devices has grown rapidly in the past few years.
Aspects and embodiments of the invention were devised with the foregoing in mind.
According to a first aspect, there is provided An aerosol delivery device comprising: a first aerosol generator to generate a first aerosol from a first aerosol precursor and to introduce the first aerosol into a first fluid flow pathway, wherein the first aerosol is sized for pulmonary penetration; a second aerosol generator to generate a second aerosol from a second aerosol precursor and to introduce the second aerosol into a second fluid flow pathway, wherein the second aerosol is sized to inhibit pulmonary penetration; wherein the second aerosol is transmissible within at least one of: a mammalian oral cavity and a mammalian nasal cavity, and the second aerosol comprising an active component for activating at least one of: one or more taste receptors in the oral cavity and one or more olfactory receptors in the nasal cavity.
Advantageously, the second aerosol is at least one of: sized to inhibit penetration to the trachea; sized to inhibit penetration to the larynx; sized to inhibit penetration to the laryngopharynx; and sized to inhibit penetration to the oropharynx.
Advantageously, the second aerosol has a mass median aerodynamic diameter that is greater than or equal to 15 microns, in particular greater than 30 microns, more particularly greater than 50 microns, yet more particularly greater than 60 microns, and even more particularly greater than 70 microns.
Advantageously, the second aerosol has a maximum mass median aerodynamic diameter that is less than 300 microns, in particular less than 200 microns, yet more particularly less than 100 microns.
Advantageously, the first aerosol precursor comprises components such that the first aerosol comprises a pulmonary deliverable active component.
Advantageously, the first aerosol has a mass median aerodynamic diameter less than or equal to 10 microns, preferably less than 8 microns, more preferably less than 5 microns, yet more preferably less than 1 micron.
Advantageously, the first aerosol generator is configured to heat the first aerosol precursor.
Advantageously, the first aerosol generator is configured to agitate the first aerosol precursor.
Advantageously, the first fluid flow pathway further receives the first aerosols from a first aerosol inlet of the device.
Advantageously, the first aerosol inlet is configured to inject the first aerosol into the first fluid flow pathway.
Advantageously, the second fluid flow pathway further receives the second aerosol from a second aerosol inlet of the device.
Advantageously, the second aerosol inlet is configured to inject the second aerosols into the second fluid flow pathway.
Advantageously, the first fluid pathway and the second fluid flow pathway merge together.
Advantageously, the first fluid pathway and the second fluid flow pathway are contiguous.
Advantageously, the second fluid flow pathway is disposed along a longitudinal axis of the first fluid flow pathway.
Advantageously, the first fluid flow pathway is disposed proximal to a gas inlet of the device and the second fluid flow pathway is disposed proximal to an aerosol outlet of the device.
Advantageously, the second fluid flow pathway is disposed proximal to a gas inlet of the device and the first fluid flow pathway is disposed proximal to an aerosol outlet of the device.
Advantageously, the second fluid flow pathway is disposed co-axially relative to the first fluid flow pathway.
Advantageously, the second fluid flow pathway is disposed adjacent the first fluid flow pathway in a side by side relationship therewith.
Advantageously, the first fluid flow pathway is separated from the second fluid flow pathway by a wall member.
Advantageously, the first fluid flow pathway comprising a first housing to constrain the fluid flow and the second fluid flow pathway comprising a second housing to constrain the second fluid flow, the first housing to receive the first aerosol; and the second housing to receive the second aerosol.
Advantageously, the first housing comprising the first aerosol generator and/or the second housing comprising the second aerosol generator.
Advantageously, the first housing comprises a removable module of the delivery device.
Advantageously, the first housing comprises a replaceable module of the delivery device.
Advantageously, the first housing comprises a refillable module of the delivery device.
Advantageously, the second housing comprises a removable module of the delivery device.
Advantageously, the second housing comprises a replaceable module of the delivery device.
Advantageously, the second housing comprises a refillable module of the delivery device.
Advantageously, the first aerosol precursor comprises nicotine, or a nicotine derivative, or a nicotine analogue.
Advantageously, the first aerosol precursor comprises a pulmonary deliverable active component that is a free nicotine salt comprising at least one of: nicotine hydrochloride; nicotine dihydrochloride; nicotine monotartrate; nicotine bitartrate; nicotine bitartrate dihridrate; nicotine sulphate; nicotine zinc chloride monohrydrate; and nicotine salicylate.
Advantageously, the second aerosol being transmissible to activate at least one of: one or more taste receptors in the oral cavity; and one or more olfactory receptors in the nasal cavity.
Advantageously, the first aerosol generator is configured to generate the first aerosol from a first aerosol precursor comprising at least one of: glycol; polyglycol; and water.
Advantageously, the second aerosol generator is configured to introduce the second aerosol into the fluid flow pathway at a pre-set period of time following an actuation of the first aerosol generator.
Advantageously, the second fluid flow pathway comprises at least one baffle configured such that a portion of the second aerosol impinges on the baffle.
Advantageously, the aerosol inlet port is configured to introduce the second aerosol of a mass median aerodynamic diameter to inhibit pulmonary penetration.
Advantageously, the second aerosol generator comprises a Venturi aperture to dispense and aerosolise the second aerosol precursor in the second aerosol generator, wherein the second aerosol precursor is a liquid.
Advantageously, the second aerosol generator comprises a piezoelectric element to dispense and aerosolise the second aerosol precursor in the second aerosol generator, wherein the second aerosol precursor is a liquid.
Advantageously, the second aerosol generator comprises a precursor substrate for the second aerosol precursor, wherein the precursor substrate comprises a hydrophobic surface.
Advantageously, the second aerosol generator comprises a plurality of capillary tubes configured to draw the second aerosol precursor from a reservoir of second aerosol precursor to a free end of the plurality of capillary tubes.
Advantageously, the free end of the plurality of capillary tubes is hydrophobic.
Advantageously, the first aerosol is of a size suitable for deep lung penetration.
Advantageously, the first aerosol has a mass median aerodynamic diameter less than 2 μm.
Advantageously, the second fluid flow pathway terminates in a second fluid flow pathway mouthpiece.
Advantageously, the first fluid flow pathway terminates in a first fluid flow pathway mouthpiece.
Advantageously, the first and second fluid flow pathways terminate in a combination mouthpiece.
Advantageously, the combination mouthpiece comprises separate pathways corresponding to the first and second fluid flow pathways respectively.
Advantageously, the merged first and second fluid flow pathways terminate in a mouthpiece.
Advantageously, the active component comprises a physiologically active component.
According to a second aspect, a first fluid pathway housing is provided, the first fluid pathway housing being for an aerosol delivery device according to the first aspect.
Advantageously, the first fluid pathway housing comprises the first aerosol precursor.
Advantageously, the first fluid pathway housing comprises the first aerosol generator.
According to a third aspect, a second fluid pathway housing is provided, the second fluid pathway housing being for an aerosol delivery device according to the first aspect.
Advantageously, the second fluid pathway housing comprises the second aerosol precursor.
Advantageously, the second fluid pathway housing comprises the second aerosol generator.
According to a fourth aspect, a kit of parts is provided, the kits of parts being for an aerosol delivery device according to the first aspect, the kit of parts including a first fluid pathway housing according to the second aspect and a second fluid flow pathway housing according to the third aspect.
One or more specific embodiments in accordance with aspects of the present invention will be described, by way of example only, and with reference to the following drawings in which:
By way of general overview,
Smoking substitute devices, such as an e-cigarette, may be refillable to replace consumed e-liquid. An example of the heating, e-liquid reservoir and mouthpiece regions of an e-cigarette 10, known as a clearomiser, is illustrated in
Flavour is experienced by a user through taste and/or olfactory receptors located in their oral and nasal cavities. The inventors have recognised that flavour aerosols may penetrate into the oral and nasal cavities to deliver the flavour component to the user without penetrating any further. However, physiologically active substances such as pharmaceutical compounds and nicotine may be more effectively delivered through the pulmonary system, in particular through deep lung penetration.
Turning now to
A user is to place the mouthpiece 30 into their mouth with side B protruding from their mouth and to draw air to side A from side B to cause an airflow from side B through the flavour element 38 and consequently to draw flavour aerosols into the user's mouth. The user may activate the vaping apparatus 34 to generate an aerosol mist from the e-liquid precursor in the vaping apparatus by drawing air on the A side of mouthpiece 30. By activating the vaping apparatus 34 while drawing air through mouthpiece 30 a user will take both aerosols from the vaping apparatus containing an active component and flavour aerosols from flavour element 38.
The aerosols generated in vaping apparatus 34 are formed by the heating of a vapour pre-cursor liquid such that they are typically of a size with a mass median aerodynamic diameter less than or equal to 10 microns, preferably less than 8 microns, more preferably less than 5 microns, yet more preferably less than 1 micron. Such sized aerosols tend to penetrate into a human user's pulmonary system. The smaller the aerosol the more likely it is to penetrate deeper into the pulmonary system and the more effective the transmission of the active component into the user's blood stream. Such deep lung penetration is something that is desirable for the active component but unnecessary for the flavour component. The flavour component may enter a user's oral and or nasal cavities in order to activate taste and or olfactory receptors and not penetrate the pulmonary system.
The flavour component is configured such that it is typically forms an aerosol with a mass median aerodynamic diameter that is greater than or equal to 15 microns, in particular, greater than 30 microns, more particularly greater than 50 microns, yet more particularly greater than 60 microns, and even more particularly greater than 70 microns. Without being bound by any theory, such a size of aerosol may be formed by drawing liquid droplets from a substrate at the ambient temperature of a user's environment, e.g. room temperature, by an airflow over the substrate. The size of aerosol formed without heating is typically smaller than that formed by condensation of a vapour. The size of the aerosols formed without heating such as drawing air over a substrate supporting the liquid may be influenced by the ambient temperature, the viscosity and or density of the liquid. However, it is generally, and most likely to be the case, that aerosols formed without heating are of a considerably larger size than those formed through heating. The flavour aerosols may be formed with a maximum mass median aerodynamic diameter that is less than 300 microns, in particular less than 200 microns, yet more particularly less than 100 microns. Such a range of mass median aerodynamic diameter will produce aerosols which are sufficiently small to be entrained in an airflow caused by a user drawing air through the flavour element 38 and to enter and extend through the oral and or nasal cavity to activate the taste and/or olfactory receptors.
As a brief aside, it will be appreciated that the mass median aerodynamic diameter is statistical measurement of the size of the particles/droplets in an aerosol. That is, the mass median aerodynamic diameter quantifies the size of the droplets that together form the aerosol. The mass median aerodynamic diameter may be defined as the diameter at which 50% of the particles/droplets by mass in the aerosol are larger than the mass median aerodynamic diameter and 50% of the particles/droplets by mass in the aerosol are smaller than the mass median aerodynamic diameter. The “size of the aerosol”, as may be used herein, refers to the size of the particles/droplets that are comprised in the particular aerosol. The size of the particles/droplets in the aerosol may be quantified by the mass median aerodynamic diameter, for example.
The size of the aerosol generated by an aerosol generator may depend on, for example, the temperature of the liquid precursor, the density of the liquid precursor, the viscosity of the liquid precursor, or a combination. The size of the aerosol generated by an aerosol generator may also depends on the particular parameters and configuration of the aerosol generating apparatus, which are described in more detail below.
Flavour element 38 may be formed of any suitable porous material for providing the substrate. For example, it may be formed of a material typically used as a filter for a cigarette or the substrate material for a Nicorette Inhalator™, i.e. a porous polypropylene or polyethylene terephthalate. A liquid flavour component may then be dripped on to the flavour element 38. Flavour element 38 substrate may comprise a porous material where pores of the porous material hold, contain, carry, or bear a flavour compound. Optionally or additionally, the porous material may comprise a sintered material such as, for example, BioVyon™ (by Porvair Filtration Group Ltd).
In the embodiment illustrated in
Flavour element 54 is disposed in flavour pod 50 so as to rest on helical spring 56. A piezo-electric vibration unit 60 is disposed in contact with an end of flavour element 54 and is powered through electrical connection 62. Piezo-electric element 60 comprises a piezo-electric crystal electrically couplable to a power supply, such as an electrical battery, through connection 62. The piezo-electric element 60 includes a perforated membrane vibrated by a piezo-electric crystal or formed of the piezo-electric crystal itself. The perforations in the vibratable membrane form small droplets of liquid flavour component adsorbed in flavour element 54 when the membrane is vibrated. The vibration is typically in the range 100 kHz to 2.0 MHz, in particular between 108 kHz and 160 kHz, and more particularly at substantially 108 kHz, for example. Such vibration frequencies may be used to form aerosols of the liquid flavour component which may be drawn by airflow from the flavour element 54 to the terminal end of mouthpiece 50 and are of a size as set out in the ranges above.
Electrical connection 62 may be coupled to a power supply through a switch operative by a user or responsive to a pressure drop in the fluid pathway 42/cavity 58 as a user draws air from the mouthpiece 40. Optionally, electrical connection 62 may be coupled through a switch on the vape apparatus (SMP) so that the piezo-electric element 60 is actuated when a user actuates the vape apparatus.
Another configuration for apparatus which comprises separate flavour and nicotine aerosol delivery is illustrated in
For the avoidance of doubt, in the following description of
A cross-sectional side view of the apparatus 150 is schematically illustrated in
Vaporizer portion 164 of aerosol generation unit 162 comprises a reservoir 176 configured to contain a vapour precursor material, a vaporizing arrangement 178 configured to vaporize the vapour precursor material and a fluid flow pathway passage 180 for delivery of aerosols formed from the vapour precursor material to the fluid flow pathway passage 170 of the aerosol outlet conduit 168.
The vapour precursor material may be in liquid form and may comprise one or more of glycol, polyglycol, propylene glycol and water.
The vaporizing arrangement 178 comprises a chamber (not shown) for holding vapour precursor material received from the reservoir 176 and a heating element (not shown) for heating vapour precursor material in the chamber.
The vaporizing arrangement 178 further comprises a conduit (not shown) in fluid communication with the chamber and configured to deliver aerosols formed from heated vapour precursor material in the chamber to the vapour passage 180.
The vaporizing arrangement 178 further comprises control circuitry (not shown) operative by a user, or upon detection of air and/or aerosols being drawn though the aerosol outlet conduit 168, i.e. when the user sucks or inhales.
Battery portion 166 of the aerosol creation system 162 comprises a battery 182 and a coupling 184 for mechanically and electrically coupling the battery portion 166 to the vaporizer portion 164. When the battery portion 166 and vaporizer portion 164 are coupled as shown in
Responsive to activation of the control circuitry of vaporizing arrangement 178, the heating element heats vapour precursor material in the chamber of the vaporizing arrangement 178. Vapour formed as a result of the heating process forms an aerosol of liquid condensate which passes through the conduit into the fluid pathway passage 180 of the vaporizer portion 164. This aerosol comprising fluid then passes into an upstream region of aerosol fluid pathway 170 of the aerosol outlet conduit 168, through the flavour element 172, where flavour from the substrate 174 becomes entrained in the aerosol stream, and then onwards through the downstream region of aerosol fluid pathway 170 for delivery to the user.
This process is illustrated in
Flavour element 70 may also be disposed in apparatus 150 in place of the flavour element 172 illustrated in
The capillary filaments are of a diameter to form aerosol-sized droplets within the ranges set out above. Generally, an open-end aperture of a diameter around the desired median diameter of the aerosol to be generated produces an aerosol of such median diameter. The exact size of the particles/droplets comprised in the aerosol will depend on the surface tension and temperature of the liquid flavour component as well as the pressure exerted on it, amongst other things. In the described embodiment the capillary filaments, or at least there open-end, are of a hydrophobic material in order to generate release of droplets of liquid.
In the embodiment schematically illustrated in
A further embodiment in accordance with the present invention is schematically illustrated in
In an optional embodiment, active component aerosol generator 106 may be disposed in a circumferential arrangement about the flavour aerosol generator 102/104.
In the embodiment schematically illustrated in
The flavour aerosol generators of any of the embodiments disclosed in
For clarification, the active component aerosol generators in the foregoing described embodiments are configured to generate aerosols sized for pulmonary penetration, in particular deep lung penetration, and generally to generate active component aerosols sized to have a mass median aerodynamic diameter less than or equal to 10 microns, preferably less than 8 microns, more preferably less than 5 microns, yet more preferably less than 1 micron. It is the case that aerosols formed from a vapour condensate, i.e. an aerosol mist, such as occurs in a typical E-cigarette or vaping apparatus are likely to fall within the defined size ranges, or at least a significant proportion of them will fall within the defined size ranges. For example, 50% of the active component aerosols falling within the defined size ranges may be reasonably expected. It is preferable if a greater percentage falls within the defined size range, for example 75% or even higher. However, it may be acceptable to have a lower percentage such as down to 25% of the active component aerosols within the defined size ranges.
Flavour component aerosols may be generated in a number of ways of which some have been described above. The creation of aerosols (sometimes referred to as “atomisation”) has been described in technical and scientific literature and such techniques may be applied, adapted to or modified for the flavour aerosol generators and elements the utilisation embodiments in accordance with the present invention. An overview of aerosolisation and techniques and methods for generating aerosols will now be provided. For the avoidance of doubt, references to droplet or particle are also references to aerosols may comprise a droplet such as a vapour condensate and/or a solid particle.
Aerosols are formed initially from atomisation or from the condensing of vapour. Atomisation is the process of breaking up bulk fluids into droplets or particles. The process of breaking up the bulk fluids into a spray or aerosol that carries particles is commonly achieved using a so-called atomizer. Common examples of atomizers include shower heads, perfume sprays, and hair or deodorant sprays.
An aerosol is a collection of moving particles that are the result of atomization; for most non-naturally occurring applications of atomization the aerosol moves the particles in a controlled fashion and direction. Typically, for most everyday applications the aerosol comprises a range of particle sizes depending upon various intrinsic and environmental parameters as discussed below.
A droplet or particle of fluid has a more or less spherical shape due to the surface tension of the fluid. The surface tension causes sheets or ligaments of fluid to be unstable; i.e. to break up into particles and/or atomize. As a general rule, as the temperature of the fluid increases its surface tension tends to correspondingly decrease.
A variety of properties and factors affect the size of the droplets or particles and how easily the fluid may be atomized after being ejected from an aperture; these include surface tension, viscosity, and density.
Surface Tension: surface tension tends to stabilize a fluid preventing it from separating into droplets of particles. Fluids with a higher surface tension tend to produce droplets or particles with a larger average droplet size or diameter upon atomization.
Viscosity: the viscosity of a fluid has a similar effect on the size or diameter of the droplet or particle formed during atomization as surface tension. The viscosity of fluid resists agitation preventing the bulk fluid from breaking into droplets or particles. Consequently, fluids with a higher viscosity tend to produce droplets or particles with a larger average droplet size or diameter upon atomization.
Density: density causes the fluid to resist acceleration. Consequently, once again fluids with a higher density tend to produce droplets or particles with a larger average droplet size or diameter upon atomization.
The process of atomisation, i.e. the process that may lead to the formation of aerosols, may take a number of different forms.
Also known as airless, air-assisted airless, hydrostatic, and hydraulic atomization, the pressure atomization process involves forcing fluid through a small nozzle or orifice at high pressure so that the fluid is ejected at high speed as a solid stream or sheet. The friction between the fluid and air disrupts the stream, causing it to break into fragments initially and ultimately into droplets.
A number of factors affect the stream and droplet size including the diameter of the orifice, the external atmosphere (temperature and pressure), and the relative velocity of the fluid and air. As a general rule, the larger the diameter of the nozzle orifice, the larger the average droplet diameter in the spray.
The external atmosphere resists the spray and tends to break up the stream of fluid; this resistance tends to partially overcome the surface tension, viscosity and density of the fluid.
The relative velocity between the fluid and air has the greatest influence on the average diameter of the droplets in the aerosol. Since the velocity of the fluid ejected through the nozzle orifice is dependent upon pressure, as fluid pressure in the nozzle increases the average diameter of the droplets correspondingly decreases. Conversely, as fluid pressure decrease, the velocity is lower and the average diameter of the droplets increases.
In air atomization, fluid is ejected from a nozzle orifice 210 at relatively low speed and low pressure and is surrounded by a high-velocity stream of air 212. Friction between the fluid and air accelerates and disrupts the fluid stream and causes atomization. As the principal energy source for atomization is air pressure, the fluid flow rate can be regulated independently of the energy source. Accordingly, air atomization has been adopted as the principal technology for atomization in medical inhalation and device technologies.
At the same rotational speed, at alow fluid flow rates droplets form closer to the edge of the disk than with higher flow rates. The fluid is ejected from the edge of the disk and moves radially away from the disk in all directions (i.e. 360º). Accordingly, where the droplets may be entrained in a directional air flow or shaping bell to cause the aerosol to travel in an axial direction.
Both the flow rate of the fluid introduced onto the spinning disk or cone, and the disk speed can be controlled independently of each another.
Ultrasonic atomization relies on an electromechanical device that vibrates at high frequency. The high-frequency oscillation causes fluid passing over or through the vibrating surface to break into droplets.
There are a number of types of ultrasonic nebulisers including ultrasonic wave atomizers and vibrating mesh atomizers.
a. Ultrasonic Wave Atomizers
A thin layer of liquid is deposited on the surface of a resonator (typically a resonating surface connected to a piezo-electric element) which is then mechanically vibrated at high-frequency along direction A. The vibrations cause a pattern of standing capillary waves having a standing wavelength λ when the vibration amplitude exceeds a threshold value. Upon increasing the vibration amplitude above the threshold ligament break-up of the liquid occurs and droplets are expelled from the crests/peaks of the capillary waves.
As schematically illustrated in
The nozzle is designed so that excitation of the piezo-electric crystal comprised in the transducer create a standing wave along the length of the nozzle. The ultrasonic energy from the crystals located in the large diameter of the nozzle body undergoes a step transition and amplification as the standing wave as it traverses the length of the nozzle.
Since the wavelength is dependent upon operating frequency, nozzle dimensions are governed by frequency. In general, high-frequency nozzles are smaller, create smaller droplets, and consequently have a smaller maximum flow capacity than nozzles that operate at lower frequencies.
The nozzle is preferably fabricated from titanium because of its good acoustical properties, high tensile strength, and excellent corrosion resistance. Liquid is introduced onto the atomizing surface through a feed tube running the length of the nozzle that absorbs some of the vibrational energy, setting up a wave motion in the liquid on the surface. For the liquid to atomize, the vibrational amplitude of the atomizing surface must be carefully controlled. Below the so called critical amplitude, the energy is insufficient to produce atomized droplets and if the amplitude is excessively high the liquid is ripped apart and ‘chunks’ of fluid are ejected (a condition known as “cavitation”).
Since the ultrasonic atomization relies only on liquid being introduced onto the atomizing surface, the rate at which liquid is atomized depends solely on the rate at which it is delivered to the surface.
Ultrasonic wave atomizers are particularly suited to low pressure/low velocity applications and provide an aerosol spray that is highly controllable. Accordingly, since the atomization process is not reliant upon fluid pressure the volume of liquid that is atomized can be controlled by the liquid delivery system and can range from a few microliters upwards. In addition the aerosol spray can be precisely controlled and shaped by entraining the low-velocity aerosol spray in an ancillary air stream to produce a spray pattern that is as small as around 1.8 mm wide.
Furthermore, droplets produced by ultrasonic vibration have a relatively narrow average diameter distribution. Median droplet sizes range from 18-68 microns, depending upon the operating frequency of the nozzle. For example, Sono-tek claim that their ultrasonic spray nozzles can produce a median droplet diameter of around 40 microns with 99.9% of the droplets having a diameter falling in the range 5-200 microns.
b. Static Mesh Atomization
Static mesh atomizers apply a force to the liquid to force it through a static mesh as shown in
c. Vibrating Mesh Atomization
Vibrating mesh atomisers use mesh deformation or vibration to push liquid through the mesh as schematically shown in
The size of the droplet and aerosol produced is dependent on the size of the holes in the mesh and the physiochemical properties of the liquid. However, one of the drawbacks to vibrating mesh devices is the potential for the holes in the mesh to clog particularly with solutions that are too viscous to pass through the mesh.
More detail concerning the various techniques for generating aerosols via atomisation may be found in the following publications.
The techniques, methods and processes for atomising liquids to generate aerosols described above may be adapted or modified for use in one or more embodiments in accordance with the present invention.
In view of the foregoing description it will be evident to a person skilled in the art that various modifications may be made within the scope of the invention. For example, the helical spring of
The terms “fluid”, “fluid flow”, “air” and “airflow” refer to any suitable fluid composition, including but not limited to a gas or a gas mixed with an atomized, volatilized, nebulized, discharged, or otherwise gaseous phase or aerosol form of an active component.
The term “active component” includes “physiologically active” or “biologically active” and to comprise any single chemical species or combination of chemical species having desirable properties for enhancing an inhaled aerosol that is suitable for adsorption upon or absorption into media suitable for use in the present invention. Furthermore, a functional component in non-liquid form, which may for example be crystalline, powdered or otherwise solid, may be substituted for a functional component without departing from the scope of the invention.
As used herein any reference to “one embodiment” or “an embodiment” means that a particular element, feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. The appearances of the phrase “in one embodiment” or the phrase “in an embodiment” in various places in the specification are not necessarily all referring to the same embodiment.
As used herein, the terms “comprises,” “comprising,” “includes,” “including,” “has,” “having” or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a process, method, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Further, unless expressly stated to the contrary, “or” refers to an inclusive or and not to an exclusive or. For example, a condition A or B is satisfied by any one of the following: A is true (or present) and B is false (or not present), A is false (or not present) and B is true (or present), and both A and B are true (or present).
In addition, use of the “a” or “an” are employed to describe elements and components of the invention. This is done merely for convenience and to give a general sense of the invention. This description should be read to include one or at least one and the singular also includes the plural unless it is obvious that it is meant otherwise.
The scope of the present disclosure includes any novel feature or combination of features disclosed therein either explicitly or implicitly or any generalisation thereof irrespective of whether or not it relates to the claimed invention or mitigate against any or all of the problems addressed by the present invention. The applicant hereby gives notice that new claims may be formulated to such features during prosecution of this application or of any such further application derived therefrom. In particular, with reference to the appended claims, features from dependent claims may be combined with those of the independent claims and features from respective independent claims may be combined in any appropriate manner and not merely in specific combinations enumerated in the claims.
The following numbered clauses contain statements of broad combinations of technical features in accordance with various aspects of devices and methods disclosed herein:
Number | Date | Country | Kind |
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1715386.7 | Sep 2017 | GB | national |
This application is a continuation of U.S. patent application Ser. No. 18/191,820, filed Mar. 28, 2023, which is a continuation of U.S. patent application Ser. No. 16/648,483, filed Mar. 18, 2020, now U.S. Pat. No. 11,633,556, which is a 35 USC § 371 national stage of PCT/EP2018/075697, filed Sep. 21, 2018, which claims priority from GB1715386.7 filed Sep. 22, 2017. These applications are herein incorporated by reference.
Number | Date | Country | |
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Parent | 18191820 | Mar 2023 | US |
Child | 18733777 | US | |
Parent | 16648483 | Mar 2020 | US |
Child | 18191820 | US |