Patent Publication Number: US-10321720-B2

Title: Electronic smoking article

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation under 35 U.S.C. § 120 of U.S. application Ser. No. 14/185,259, filed Feb. 20, 2014, which claims priority under 35 U.S.C. § 119(e) to U.S. Provisional Application No. 61/768,123, filed on Feb. 22, 2013, the entire contents of each of which are incorporated herein by reference. 
    
    
     SUMMARY 
     An electronic smoking article or vaping device is provided which includes a heater-wick element which wicks liquid and heats the liquid material to produce an aerosol or “vapor.” The heater-wick element preferably comprises at least two layers of an electrically resistive mesh material. The heater-wick element also includes a wicking portion and a heatable portion, which are integrally formed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a top planar view of an electronic smoking article according to a first embodiment; 
         FIG. 2  is a side cross-sectional view of the electronic smoking article shown in  FIG. 1  including a heater-wick element including at least two layers of mesh material; 
         FIG. 3  is an enlarged view of the heater-wick element of  FIG. 2 ; 
         FIG. 4  an enlarged view of a second embodiment of a heater-wick element including at least two layers of mesh material; 
         FIG. 5  is an enlarged view of an electrical connection with a heater-wick element; and 
         FIG. 6  is a cross-sectional view of the heater-wick element of  FIG. 3 . 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIGS. 1 and 2 , an electronic smoking article (article)  60  is provided and comprises a replaceable cartridge (or first section)  70  and a reusable fixture (or second section)  72 , which in the preferred embodiment are coupled together at a threaded connection  205  or by other convenience such as a snug-fit, detent, clamp and/or clasp. Generally, the second section  72  includes a puff sensor  16  responsive to air drawn into the second section  72  via an air inlet port  45  adjacent the free end or tip of the smoking article  60 , a battery  1  and control circuitry. The disposable first section  70  includes a liquid supply region of  22  including liquid and a heater-wick element  14  that wicks liquid from the liquid supply region  22  and heats the liquid to form an aerosol in a central air channel  21 . Upon completing the threaded connection  205 , the battery  1  is electrically connected with the heater-wick element  14  of the first section  70  upon actuation of the puff sensor. Air is drawn primarily into the first section  70  through one or more air inlets  44 . 
     In the preferred embodiment, once the liquid of the cartridge is spent, only the first section  70  is replaced. An alternate arrangement includes a layout where the entire article  60  is disposed once the liquid supply region is depleted. In such case the battery type and other features might be engineered for simplicity and cost-effectiveness, but generally embodies the same concepts as in the preferred embodiment in which the second section is reused and/or recharged. 
     In a preferred embodiment, the electronic smoking article  60  is about the same size as a conventional smoking article. In some embodiments, the electronic smoking article  60  can be about 80 mm to about 110 mm long, preferably about 80 mm to about 100 mm long and about 7 mm to about 8 mm in diameter. For example, in a preferred embodiment, the electronic smoking article is about 84 mm long and has a diameter of about 7.8 mm. 
     Preferably, at least one adhesive-backed label is applied to the outer tube  6 . The label completely circumscribes the electronic smoking article  60  and can be colored and/or textured to provide the look and/or feel of a traditional smoking article. The label can include holes therein which are sized and positioned so as to prevent blocking of the air inlets  44 . 
     The first section  70  includes an outer tube (or casing)  6  extending in a longitudinal direction and an inner tube (or chimney)  62  coaxially positioned within the outer tube  6 . Preferably, a nose portion  61  of an upstream gasket (or seal)  15  is fitted into an upstream end portion  65  of the inner tube  62 , while at the same time, an outer perimeter  67  of the gasket  15  provides a liquid-tight seal with an interior surface of the outer casing  6 . The upstream gasket  15  also includes a central, longitudinal air passage  20 , which opens into an interior of the inner tube  62  that defines a central channel  21 . A transverse channel  33  (shown in  FIG. 2 ) at a backside portion of the gasket  15  intersects and communicates with the central channel  20  of the gasket  15 . This channel  33  assures communication between the central channel  20  and a space  35  (see  FIG. 2 ) defined between the gasket  15  and a cathode connector piece  37 . In the preferred embodiment, the piece  37  includes a threaded section for effecting the threaded connection  205 . 
     The outer tube  6  and/or the inner tube  62  may be formed of any suitable material or combination of materials. Examples of suitable materials include metals, alloys, plastics or composite materials containing one or more of those materials, or thermoplastics that are suitable for food or pharmaceutical applications, for example polypropylene, polyetheretherketone (PEEK), ceramic, and polyethylene. Preferably, the material is light and non-brittle. 
     In the preferred embodiment, as shown in  FIGS. 1 and 2 , the electronic smoking article  60  includes at least one air inlet  44  formed in the outer tube  6 , preferably adjacent the threaded connection  205  to minimize the chance of a smoker&#39;s fingers occluding one of the inlets and to control the resistance to draw (RTD) during smoking. In the preferred embodiment, the air inlets  44 ,  44 ′ are sized and configured such that the electronic smoking article  60  has a RTD in the range of from about 60 mm H 2 O to about 150 mm H 2 O, more preferably about 90 mm H 2 O to about 110 mm H 2 O, most preferably about 100 mm H 2 O to about 130 mm H 2 O. 
     In the preferred embodiment, the second section  72 , includes an air inlet  45  at an upstream end  5  of the smoking article  60 , which is sized just sufficient to assure proper operation of the puff sensor  16 , located nearby. Drawing action upon the mouth end insert  8  is communicated to the air inlet port  45  through central channels provided in the anode post  47   c  of the first section  70  and the anode connection post  47   b  of the second section  72  and along space  13  between the battery  1  and the casing of the second section  72 . The air inlet port  45  is sized such that the airflow rate therethrough are much smaller than through the air inlets  44 ,  44 ′, so that the impact on RTD is minimized and consistency in RTD is maintained. For example, each air inlet can be less than about 2.0 mm in width and less than about 1.5 mm in length. For example, each air inlet can be about 0.7 mm to about 0.8 mm in width and about 0.7 mm to about 0.8 mm in length. In a preferred embodiment, 95% of the air introduced in the smoking article  60  is through the air inlets  44 ,  44 ′, whereas only 5% of the total air flow enters through the inlet  45  at the upstream end  5  of the smoking article  60 . 
     Preferably, a nose portion  93  of a downstream gasket  10  is fitted into a downstream end portion  81  of the inner tube  62 . An outer perimeter  82  of the gasket  10  provides a substantially liquid-tight seal with an interior surface  97  of the outer casing  6 . The downstream gasket  10  includes a central channel  84  disposed between the central passage  21  of the inner tube  62  and the interior of the mouth end insert  8  and which communicates aerosol from the central passage  21  to the mouth end insert  8 . 
     The space defined between the gaskets  10  and  15  and the outer tube  6  and the inner tube  62  establish the confines of a liquid supply region  22 . The liquid supply region  22  comprises a liquid material and optionally a liquid storage medium operable to store the liquid material therein. The liquid storage medium may comprise a winding of cotton gauze or other fibrous material about the inner tube  62 . 
     In the preferred embodiment, the liquid supply region  22  is contained in an outer annulus between inner tube  62  and outer tube  6  and between the gaskets  10  and  15 . Thus, the liquid supply region  22  at least partially surrounds the central air passage  21 . 
     Preferably, the liquid storage medium is a fibrous material comprising cotton, polyethylene, polyester, rayon and combinations thereof. Preferably, the fibers have a diameter ranging in size from about 6 microns to about 15 microns (e.g., about 8 microns to about 12 microns or about 9 microns to about 11 microns). The liquid storage medium can be a sintered, porous, sponge, or foamed material. Also preferably, the fibers are sized to be irrespirable and can have a cross-section which has a y shape, cross shape, clover shape or any other suitable shape. In the alternative, the liquid supply region  22  may comprise a filled tank lacking a fibrous storage medium and containing only liquid material. 
     Also preferably, the liquid material has a boiling point suitable for use in the electronic smoking article  60 . If the boiling point is too high, the heater-wick element  14  will not be able to vaporize the liquid. However, if the boiling point is too low, the liquid may vaporize even when the heater-wick element  14  is not activated. 
     Preferably, the liquid material includes a tobacco-containing material including volatile tobacco flavor compounds which are released from the liquid upon heating. The liquid may also be a tobacco flavor containing material or a nicotine-containing material. Alternatively, or in addition, the liquid may include a non-tobacco material and/or a nicotine-free material. For example, the liquid may include water, solvents, ethanol, plant extracts and natural or artificial flavors. Preferably, the liquid further includes an aerosol former. Examples of suitable aerosol formers are glycerine and propylene glycol. 
     In use, liquid material is transferred from the liquid supply region  22  and/or liquid storage medium via the heater-wick element  14 , which includes at least one wicking portion  140  and a heatable portion  141 . In the preferred embodiment, the heater-wick element  14  includes two wicking portions  140  and a heatable portion  141  therebetween. Also preferably, the wicking portions  140  and the heatable portion  141  are integrally formed and are formed of the same material. 
     As shown in  FIGS. 2, 3, and 4 , the heater-wick element  14  includes at least two layers of mesh material. The heater-wick element  14  can include three or more, four or more, or five or more layers of mesh material. The layers of mesh material can be connected along a length thereof by brazing, soldering, or other suitable connection means. Preferably, the layers are pressed together, preferably without brazing, soldering or application of adhesive, so as to avoid blocking the interstices of the mesh material. 
     The heater-wick element  14  is preferably straight, but could be coiled or formed in other geometries. Moreover, the heater-wick element  14  could be inserted in through opposing slots in the inner tube  62 . Alternatively, the inner tube  62  can be slit from an edge thereof to a location along the inner tube  62  and the heater-wick element  12  can be slid through the slit and into the desired location along the inner tube  62  such that the heatable portion  141  is in the central channel  21  and each wicking portion  141  extends outside of the inner tube  62 . 
     As shown, the heater-wick element  14  extends across the central channel  21  between opposing portions of the liquid supply region  22  and into the liquid supply region  22 . Thus, the wicking portion  140  at each end of the heater-wick element  14  extends into the liquid supply region  22  so as to wick liquid into the heatable portion  141  of the heater-wick element  14 , which is positioned within the central air passage  21 . As shown in  FIG. 6 , the wicking portions  140  can extend circumferentially about the inner tube  62  within the liquid supply region  22 , and in an embodiment, may extend in a spiral about the inner tube  62 . Moreover, the heater-wick element  14  includes a first layer of mesh  14   a  and a second layer of mesh material  14   b.    
     Since the wicking portions  140  and the heatable portion  141  are both formed of the same material, a single component is used to form the heater-wick element. Thus, advantageously, manufacture of the electronic smoking article  60  is eased because the number of materials and parts is reduced. For example, there is no need to coil a heating element, such as a heater wire, about a wicking material. 
     Preferably, the heater-wick element  14  includes multiple layers of a mesh material (e.g., at least two layers, at least three layers, at least four layers or more). Examples of suitable electrically resistive materials include titanium, zirconium, tantalum and metals from the platinum group. Examples of suitable metal alloys include stainless steel, nickel-, cobalt-, chromium-, aluminium-titanium-zirconium-, hafnium-, niobium-, molybdenum-, tantalum-, tungsten-, tin-, gallium-, manganese- and iron-containing alloys, and super-alloys based on nickel, iron, cobalt, stainless steel. For example, the heater-wick element  14  can be formed of nickel aluminides, a material with a layer of alumina on the surface, iron aluminides and other composite materials, the electrically resistive material may optionally be embedded in, encapsulated or coated with an insulating material or vice-versa, depending on the kinetics of energy transfer and the external physicochemical properties required. Preferably, the heater-wick element  14  comprises at least one material selected from the group consisting of stainless steel, copper, copper alloys, nickel-chromium alloys, superalloys and combinations thereof. In a preferred embodiment, the heater-wick element  14  is formed of nickel-chromium alloys or iron-chromium alloys. 
     In another embodiment, the heater-wick element  14  may be constructed of an iron-aluminide (e.g., FeAl or Fe 3 Al), such as those described in commonly owned U.S. Pat. No. 5,595,706 to Sikka et al. filed Dec. 29, 1994, or nickel aluminides (e.g., Ni 3 Al). Use of iron-aluminides is particularly advantageous in that they exhibit high resistivity. FeAl exhibits a resistivity of approximately 180 micro-ohms, whereas stainless steel exhibits approximately 50 to 91 micro-ohms. The higher resistivity lowers current draw or load on the power source (battery)  1 . 
     Preferably, as shown in  FIGS. 2, 3, 4 and 5 , a conductive connection region (e.g., a post)  99  formed of a low-resistance material is preferably brazed to each end or at two locations along a portion of the of the heater-wick element  14 . Preferably, the brazed connection regions  99  are formed just inside of the inner tube  62  and the heatable portion  141  extends between the brazed connections regions  99 . In another embodiment, the brazed connection regions  99  are contained entirely in the outer annulus as shown in  FIGS. 3 and 4 . By forming the brazed connection regions  99 , the electrical current is uniform across the length and width of each layer of the mesh heater-wick element  14  so as to avoid hot spots. 
     For example, the conductive connection region  99  can be formed by wrapping a gold-plated wire around the layers of mesh material and brazing the wire to the mesh at selected locations so as to form a heatable portion  141  between the brazed connection regions  99 . Electrical leads  26  are attached to each brazed connection region  99  (or post), as shown in  FIG. 5 , such that, when voltage is applied by the power supply, the heatable portion  141  heats the liquid material in the heatable portion  141  to a temperature sufficient to at least partially volatilize the liquid and form an aerosol. Alternatively, the electrical leads  26  can be attached directly to the mesh heater-wick element  14 . 
     In the preferred embodiment, the mesh material heater-wick element  14  is formed of a thermally and/or electrically conductive material. Suitable materials for forming the mesh material are selected from the group consisting of stainless steel, copper, copper alloys, Inconel® available from Special Metals Corporation, which is a nickel-chromium alloy, Nichrome®, which is also a nickel-chromium alloy, and combinations thereof. 
     In a preferred embodiment, the heater-wick element  14  is constructed from wire mesh filaments having a width in the range of about 0.5 mm to about 2 mm, preferably about 1 mm, and a length in the range of about 20 mm to about 40 mm. The heater-wick element  14  has a length in the range of about 10 mm to about 15 mm, preferably about 12 mm or less, and a width in the range of about 0.5 mm to about 2.0 mm, preferably about 1.5 mm or less. At about 1.5 mm width, the heater-wick element  14  is preferably oriented longitudinally within the electronic smoking article whereas heater-wick assemblies having a smaller width may be placed in a transverse direction within the electronic smoking article. 
     In the preferred embodiment, the mesh material can range in size from about 200 mesh to about 600 mesh. In the preferred embodiment, the mesh material is about 400 mesh and includes small voids/interstices  131  between the wires that form the mesh material and between the two or more layers of the heater-wick element  14 . Preferably, the mesh material is formed with 0.001 inch or greater diameter wire, such as wire available from Smallparts, Inc. Also preferably, the wire comprising the mesh is a solid wire of about 0.0014 inch to about 0.0016 inch diameter. 
     In the preferred embodiment, the mesh material of the heater-wick element  14  has a criss-cross, checkerboard type pattern with interstices  131  (shown in  FIG. 5 ) therein. Preferably, each layer of the heater-wick element  14  comprises a single, elongate, flat layer of mesh material. Also preferably, each layer of the mesh material achieves an electrical resistance ranging from about 0.3 Ohm to about 10 Ohms, more preferably about 0.8 Ohm to about 5.0 Ohms, more preferably about 4.0 Ohms or less. 
     In addition, liquid can be drawn into the interstices  131  of the mesh material and between the layers of mesh material in the heater-wick element  14  during a power cycle of the electronic smoking article. Thus, the liquid moves along the heater-wick element from the wicking portions  140  to the heatable portion  141 . 
     Advantageously, the mesh material provides a workable range of resistivity for applications such as in electronic smoking articles. In addition, the use of a mesh heater-wick element  14  including multiple layers of mesh material allows for the formation of an electronic smoking article having a single part that acts as both a heater and a wick instead of requiring additional components. Moreover, by layering the mesh material, capillary action of the mesh material is increased so as to provide constant aerosol when heated because the mesh continually refills itself. The increase in capillary action is a result of additional interstices within the mesh and between the different layers of mesh material. 
     Advantageously, the liquid material in the liquid supply region  22  is protected from oxygen (because oxygen cannot generally enter the liquid supply region  22  via the heater-wick element  14 ). In some embodiments, the liquid material is also protected from light so that the risk of degradation of the liquid material is significantly reduced. Thus, a high level of shelf-life and cleanliness can be maintained. 
     In the preferred embodiment, the liquid supply region  22  is sized and configured to hold enough liquid material such that the electronic smoking article  60  is operable for smoking for at least about 200 seconds, preferably at least about 250 seconds, more preferably at least 300 seconds and most preferably at least about 350 seconds. Thus, liquid supply region  22  is equivalent to about one pack of traditional smoking articles. Moreover, the electronic smoking article  60  can be configured to allow each puff to last a maximum of about 5 seconds. 
     As shown in  FIGS. 2 and 4 , the first section  70  can include a mouth end insert  8  having at least two diverging outlets  24  (e.g., 3, 4, 5 or more, preferably 2 to 10 outlets or more, more preferably 6 to 8 outlets, even more preferably 2 to 6 outlets or 4 outlets). Preferably, the outlets  24  are located off-axis and are angled outwardly in relation to the central channel  21  of the inner tube  62  (i.e., divergently). Also preferably, the mouth end insert (or flow guide)  8  includes outlets  24  uniformly distributed about the perimeter of mouth end insert  8  so as to substantially uniformly distribute aerosol in a smoker&#39;s mouth during use and create a greater perception of fullness in the mouth. Thus, as the aerosol passes into a smoker&#39;s mouth, the aerosol enters the mouth and moves in different directions so as to provide a full mouth feel. In contrast, electronic smoking articles having a single, on-axis orifice tend to direct its aerosol as single jet of greater velocity toward a more limited location within a smoker&#39;s mouth. 
     In addition, the diverging outlets  24  are arranged and include interior surfaces  83  such that droplets of unaerosolized liquid material, if any, that may be entrained in the aerosol impact the interior surfaces  83  of the mouth end insert  8  and/or impact portions of walls  305  which define the diverging outlets  24 . As a result such droplets are substantially removed or broken apart, to the enhancement of the aerosol. 
     In the preferred embodiment, the diverging outlets  24  are angled at about 5° to about 60° with respect to the longitudinal axis of the outer tube  6  so as to more completely distribute aerosol throughout a mouth of a smoker during use and to remove droplets. In a preferred embodiment, there are four diverging outlets  24  each at an angle of about 40° to about 50° with respect to the longitudinal axis of the outer tube  6 , more preferably about 40° to about 45° and most preferably about 42°. 
     Preferably, each of the diverging outlets  24  has a diameter ranging from about 0.015 inch to about 0.090 inch (e.g., about 0.020 inch to about 0.040 inch or about 0.028 inch to about 0.038 inch). The size of the diverging outlets  24  and the number of diverging outlets  24  can be selected to adjust the resistance to draw (RTD) of the electronic smoking article  60 , if desired. 
     The mouth end insert  8  may be integrally affixed within the tube  6  of the cartridge  70 . Moreover, the mouth end insert  8  can be formed of a polymer selected from the group consisting of low density polyethylene, high density polyethylene, polypropylene, polyvinylchloride, polyetheretherketone (PEEK) and combinations thereof. The mouth end insert  8  may also be colored if desired. 
     In the preferred embodiment, the power supply  1  includes a battery arranged in the electronic smoking article  60  such that the anode  47   a  is downstream of the cathode  49   a . A battery anode post  47   b  of the second section  72  preferably contacts the battery anode  47   a.    
     More specifically, electrical connection between the anode  47   a  of the battery  1  and the heater-wick element  14  in the first section  70  is established through a battery anode connection post  47   b  in the second section  72  of the electronic smoking article  60 , an anode post  47   c  of the cartridge  70  and an electrical lead  47   d  connecting a rim portion of the anode post  47   c  with the heater-wick element  14 . Likewise, electrical connection between the cathode  49   a  of the battery  1  and the other lead of the heater-wick element  14  is established through the threaded connection  205  between a cathode connection fixture  49   b  of the second portion  72  and the cathode connector piece  37  of the first section  70  and from there through an electrical lead  49   c  which electrically connects the fixture  37  to the opposite lead of the heater-wick element  14 . 
     The battery can be a Lithium-ion battery or one of its variants, for example a Lithium-ion polymer battery. Alternatively, the battery may be a Nickel-metal hydride battery, a Nickel cadmium battery, a Lithium-manganese battery, a Lithium-cobalt battery or a fuel cell. In that case, preferably, the electronic smoking article  60  is usable by a smoker until the energy in the power supply is depleted or in the case of lithium polymer battery, a minimum voltage cut-off level is achieved. 
     Alternatively, the power supply  1  may be rechargeable and include circuitry allowing the battery to be chargeable by an external charging device. In that case, preferably the circuitry, when charged, provides power for a pre-determined number of puffs, after which the circuitry must be re-connected to an external charging device. To recharge the electronic smoking article  60 , an USB charger or other suitable charger assembly can be used. 
     Preferably, the electronic smoking article  60  also includes control circuitry including a puff sensor  16 . The puff sensor  16  is operable to sense an air pressure drop and initiate application of voltage from the power supply  1  to the heater-wick element  14 . As shown in  FIG. 2 , the control circuitry can also include a heater activation light  48  operable to glow when the heatable portion  141  of the heater-wick element  14  is activated. Preferably, the heater activation light  48  comprises an LED and is at an upstream end of the electronic smoking article  60  so that the heater activation light  48  takes on the appearance of a burning coal during a puff. Moreover, the heater activation light  48  can be arranged to be visible to the smoker. In addition, the heater activation light  48  can be utilized for smoking article system diagnostics or to indicate that recharging is in progress. The light  48  can also be configured such that the smoker can activate and/or deactivate the light  48  for privacy, such that the light  48  would not activate during smoking if desired. 
     Preferably, the at least one air inlet  45  ( FIG. 1 ) is located adjacent the puff sensor  16 , such that the puff sensor  16  senses air flow indicative of a smoker taking a puff and activates the power supply  1  and the heater activation light  48  to indicate that the heatable portion  141  of the heater-wick element  14  is working. 
     A control circuit is preferably integrated with the puff sensor  16  and supplies power to the heater-wick element  14  responsive to the puff sensor  16 , preferably with a maximum, time-period limiter. 
     Alternatively, the control circuitry may include a manually operable switch for a smoker to initiate a puff. The time-period of the electric current supply to the heater-wick element may be pre-set depending on the amount of liquid desired to be vaporized. Alternatively, the circuitry may supply power to the heater-wick element  14  as long as the puff sensor  16  detects a pressure drop. 
     Preferably, when activated, the heater-wick element  14  heats and volatilizes liquid in contact with the heater-wick element  14  for less than about 10 seconds, more preferably less than about 7 seconds. Thus, the power cycle (or maximum puff length) can range in period from about 2 seconds to about 10 seconds (e.g., about 3 seconds to about 9 seconds, about 4 seconds to about 8 seconds or about 5 seconds to about 7 seconds). 
     Preferably, the heater-wick element  14  heats liquid by thermal conduction. Alternatively, heat from the heater-wick element  14  may be conducted to the liquid by means of a heat conductive element or the heater-wick element  14  may transfer heat to the incoming ambient air that is drawn through the electronic smoking article  60  during use, which in turn heats the liquid by convection. 
     When the word “about” is used in this specification in connection with a numerical value, it is intended that the associated numerical value include a tolerance of ±10% around the stated numerical value. Moreover, when reference is made to percentages in this specification, it is intended that those percentages are based on weight, i.e., weight percentages. 
     Moreover, when the words “generally” and “substantially” are used in connection with geometric shapes, it is intended that precision of the geometric shape is not required but that latitude for the shape is within the scope of the disclosure. When used with geometric terms, the words “generally” and “substantially” are intended to encompass not only features which meet the strict definitions but also features which fairly approximate the strict definitions. 
     It will now be apparent that a new, improved, and nonobvious electronic smoking article has been described in this specification with sufficient particularity as to be understood by one of ordinary skill in the art. Moreover, it will be apparent to those skilled in the art that numerous modifications, variations, substitutions, and equivalents exist for features of the electronic smoking article which do not materially depart from the spirit and scope of the invention. Accordingly, it is expressly intended that all such modifications, variations, substitutions, and equivalents which fall within the spirit and scope of the invention as defined by the appended claims shall be embraced by the appended claims.