Patent Publication Number: US-10314335-B2

Title: Electronic cigarette

Description:
RELATED APPLICATIONS 
     The present application is a National Phase entry of PCT Application No. PCT/GB2014/051332, filed Apr. 30, 2014, which claims the benefit of GB Application No. 1307960.3, filed May 2, 2013, each of which is incorporated herein by reference in its entirety. 
     TECHNICAL FIELD 
     Embodiments relate to an electronic cigarette. 
     SUMMARY 
     Embodiments of electronic cigarette described herein comprise a generally cylindrical housing with a proximal mouth end and a distal end, and within the housing: a vaporizer to produce vapor to be delivered to the mouth end, a battery, and sensor circuitry to detect a user drawing on the mouth end and to connect the battery to power the vaporizer to produce vapor, the vaporizer comprising: a tube having inlet and outlet ends and extending longitudinally of the housing, supports at opposite ends of the tube for directing airflow into and out of the tube from the inlet to the outlet, a porous matrix containing a vaporizable liquid extending around the tube, wicking extending through side openings in the tube and configured to wick the vaporizable liquid from the porous matrix into the tube, and an electrical heater coil in the tube configured to be powered by the battery to vaporize liquid on the wicking fibers in the tube, so that vapor is supplied along the tube to the outlet end when the user draws thereon, wherein the wicking fibers are wrapped around the outer surface of the tube so as to contact and receive the vaporizable liquid by capillary action from the matrix. 
     The wicking fibers may be wrapped around the tube in a spiral pattern. The wicking fibers may extend towards the inlet or the outlet end of the tube or both ends. 
     Furthermore, the wicking fibers may emanate from at least one of the side openings in first and second bundles which are wrapped in different wrapping patterns around the tube, for example in different directions and/or with different hands. 
     The supports for the tube may include a mouth end stopper that is push-fitted into the mouth end of the housing, which includes a mouthpiece spigot onto which the outlet end of the tube is received, and an outlet passageway extending through the spigot to provide an outlet for vapor from the tube. 
     Also, the supports for the tube may include an annular support member that includes a peripheral surface to engage with the interior of the housing, an inlet spigot on which the inlet end of the tube is mounted, and an inlet passageway extending through the inlet spigot to provide an inlet for air into the tube. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments of electronic cigarette will now be described in more detail by way of example with reference to the accompanying drawings, in which: 
         FIG. 1  is a schematic perspective view of an electronic cigarette. 
         FIG. 2  is a longitudinal section through the electronic cigarette shown in  FIG. 1 . 
         FIG. 3  is an exploded, partial perspective view of the vaporizer illustrated in  FIG. 2 , showing its heater element in a tube. 
         FIG. 4  is an enlarged portion of the sectional view shown in  FIG. 2  in the region of its heater element. 
         FIGS. 5A and 5B  illustrate alternative wrapping patterns for the wicking fibers around the tube. 
         FIG. 6  is a schematic view of portions of an alternative embodiment of vaporizer. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIGS. 1 and 2 , an electronic cigarette  1  includes a generally cylindrical housing  2  conveniently in the form of a tube of plastics material that extends from a proximal or mouth end  3  to distal end  4 . An end cap  5  of translucent plastics material is push-fitted into the distal end  4  and a mouth end stopper  6  is similarly fitted into the mouth end  3 . The tube  2  is flexible and given rigidity in part by its internal components, as will be described in more detail hereinafter. The tube in one example is made of polypropylene. 
     As shown in  FIG. 2 , the end cap  5  includes an air inlet  7  so that when the user draws on the mouth end  3 , air is drawn into the housing  2  and vapor is supplied to the user through the mouth end  3  as will be described hereinafter. 
     The housing  2  contains a battery  8 , sensor circuitry  9  and a vaporizer  10  that produces a vapor to be supplied to the user. 
     The vaporizer  10  is illustrated in more detail in  FIGS. 3 and 4 . The vaporizer  10  includes a tube  11 , conveniently made of fiberglass material which extends from an inlet end  12  to outlet end  13 . The tube  11  includes diametrically opposed side openings  14   a,b  through which wicking fibers  15  extend, so as to extend diametrically across the interior of the tube  11  and lie along its outer surface  11   a . The wicking fibers  15  are conveniently made of heat resistant material such as fiberglass. In the example shown in  FIGS. 3, 4 and 5A , the fibers  15  are wrapped in a spiral pattern around the outer surface  11   a  of the tube  11  towards both its inlet end  12  and outlet end  13 . In this example, fibers  15   a  extending out of side opening  14   a  are wound in a spiral towards the outlet end  13  and fibers  15   b  extending out of side opening  14   b  are wound in a spiral towards the inlet end  12 , with the same hand as fibers  15   a . However, other winding patterns can be used. For example as shown in  FIG. 5B , the fibers  15   a ,  15   b  are both wound in a spiral pattern towards the outlet end  13  of the tube  11 , with opposite hands. 
     Other winding patterns can be used such as a serpentine pattern around the outer surface  11   a  of tube  11 . Also the fibers  15   a  and/or  15   b  could be divided into bunches and each wound differently around the tube  11 , with the same or different winding patterns in the same or different directions along the tube  11 , with the same or different hands. 
     The wrapping of the fibers  15  around the outer surface  11   a  of the tube improves the operation of the vaporizer  10 , as will be explained in more detail hereinafter. 
     An electrical heater coil  16  extends diametrically across the tube  11 , with the wicking fibers  15  passing axially within the coil  16 . Electrical leads  17   a ,  17   b  supply electrical power to the coil  16  from the battery  8  under the control of the sensor circuitry  9  shown in  FIG. 2 . 
     A porous matrix that comprises first and second sheets of fibrous material  18 ,  19  is loaded with a vaporizable material, for example a nicotine and glycerol solution. 
     The sheet  18  has a lower surface area and absorbency than the surrounding sheet  19  which can retain a larger volume of the liquid. Typically, the sheet  19  has a larger pore size than the sheet  18 . The sheet  18  however facilitates transfer of the liquid t 0  the wicking fibers  15  so that the liquid is wicked along the core of the heater coil  16 . 
     One end of the vaporizer  10  includes an annular support member  20  that has a peripheral surface  21  that engages with the interior surface of the cylindrical housing  2 . The annular support member  20  has a generally circular end face  22  extending diametrically across the housing  2  from which an axial inlet spigot  23  extends towards the mouth end  3  and receives the inlet end  12  of tube  11 . The overlying ends of the sheets  18 ,  19  are retained between an annular, depending flange  24  and the inlet spigot  23  at the inlet end of tube  11 , and generally fill the space between the interior surface of housing  2  and the tube  11 . The annular support member  20  is conveniently flexible and made of silicon for example, so that it can be easily manipulated into housing  2  during manufacture. The sheets  18 ,  19  are wrapped around the tube  11  and thereby locate the wicking fibers  15  along the length of the outer surface of the tube  11 . 
     Spigot  23  includes a through hole to provide an air inlet passageway  23   a  into the tube  11 . 
     A mouth end stopper  6  includes a mouthpiece spigot  25  that receives the outlet end  13  of tube  11 . The mouth end stopper  6  includes an axial outlet passageway  26  through the spigot to pass vapor to a user through the mouth end  3  of housing  2 . Also, the mouth end stopper  6  includes a depending flange  27  so that the mouth end stopper  6  can be push-fitted into the mouth end  3  of housing  2 . The outlet end  13  of tube  11  may extend slightly beyond the matrix  18 ,  19 . Thus there is a gap between the matrix  18 ,  19  and the mouth end  3  of the housing  2 . Also, the mouthpiece spigot  25  which extends into the tube outlet end  13  is longer than the depending flange  27  that engages with the housing  2 , so as to provide a gap between the porous matrix  18 ,  19  and the end stopper  6 . This arrangement prevents or reduces leakage of the liquid held in the sheets  18 ,  19  through the mouth end  3  of the housing  2 . 
     Thus, the annular support member  20  and the mouth end stopper  6  with their respective spigots  23 ,  25  cooperate with the tube  11  and the housing  2  to provide a closed plenum containing the porous sheets  18 ,  19  so as to retain the nicotine containing liquid in the sheets  18 ,  19  without leakage from the housing  2 , and to allow the liquid to wick along wicking fibers  15  to be vaporized on operation of the heater coil  16 . 
     An advantage of winding the fibers  15   a ,  15   b  around the outer surface  11   a  of the tube  11  for example in a spiral pattern, is that the wicking fibers  15  receive the nicotine containing liquid from porous matrix layers  18 ,  19  all around the circumference of the tube  11  rather than from just two longitudinal regions as would occur if the fibers  15  run in a straight line longitudinally of the outer surface of the tube  11 . Thus a more reliable and complete transfer of the liquid to the wicking fibers  15  occurs by capillary action from the matrix  18 ,  19  as result of the fiber winding pattern. 
     A washer  28 , conveniently made of rigid plastics material such as polypropylene, is provided between the vaporizer  10  and battery  8  to provide rigidity to the housing  2  in the region of the annular support member  20 . The washer  28  includes an air passageway opening  29  and also openings  30  which receive the electrical leads  17   a ,  17   b . The tubular housing  2  thus is relatively rigid to the touch of the user&#39;s fingers in the region of the battery  8  and the washer  28  but is more resilient to the touch in the region containing the vaporizer  10  to provide characteristics of tactility that are similar to those of a conventional tobacco containing cigarette. 
     An air passageway extends from the inlet opening  7  in the end cap  5  between the sensor circuitry  9  and battery  8  to the air passageway  29  in the washer  28  and thence to the inlet  12  of tube  11 . 
     The sensor circuitry  9  may include a light source in the form of LED  31  which, when operated is visible through the translucent end cap  5 . 
     When the user draws on the mouth end  3 , air is drawn through the air inlet  7  in the direction of arrow A past the battery  8  and into the tube  11 . The drawing action reduces the air pressure within the housing  2 , which is sensed by the sensor circuitry  9 . In response, electrical power from the battery  8  is switched by the sensor circuitry  9  to pass through leads  17   a ,  17   b  and energize heater coil  16 . As a result, liquid which has been wicked by the wicking fibers  15  from the surrounding porous matrix layers  18 ,  19  is heated and thereby vaporized so that a stream of nicotine containing vapor is passed through the outlet passageway  26  for the user. Also, in response to the pressure reduction, the sensor circuitry illuminates the LED  31  to mimic the burning of a conventional tobacco containing cigarette. 
     Also, referring to  FIGS. 3 and 4 , atomization apertures  32  are formed in the tube  11  so that when the user draws on the mouth end  3 , the resulting pressure reduction in tube  11  draws liquid from the surrounding porous matrix layers  18 ,  19  through the apertures  32  and as a result, the liquid is atomized, thereby producing an atomized stream  33  shown in  FIG. 4 . In this example, the atomization apertures  32  are provided between the inlet end  12  of tube  11  and the heater coil  16  so that the atomized droplets  33  then pass the heater  16 , which encourages further vaporization of the atomized liquid. 
     Typically, the atomization apertures  32  are of a diameter between 0.1-0.5 mm. In the example of  FIG. 3 , the atomization apertures  32  are shown diametrically opposite one another but other configurations are possible, for example a distributed arrangement along the tube  11 , which may be spatially uniform or otherwise. Also, one or more of apertures  32  may be provided downstream of the heater coil  16 , towards the outlet end of the tube  11 . 
     A modified arrangement is illustrated in  FIG. 6  with an alternative form of side openings to receive the wicking fibers  15 . The coil  16  can be slid into an elongate slot  34  formed in tube  11  which is then closed by means of an overlying cylindrical sheath  35  that is conveniently is made of fiberglass material and slid into place from the outlet end  13  of tube  11 . In this example, the wicking fibers  15   b  extend in a spiral towards the inlet opening  12  of tube  11 , with the advantage that their ends can be sandwiched between the tube  11  and the porous matrix sheet, and held firmly between the region of the tube  11  on spigot  23  and the depending flange  24  of the annular support member  20 . 
     In another modification, the device shown in  FIGS. 1 and 2  may have a two part housing  2  so that the vaporizer  10  is attached to the battery  8  and sensor circuitry  9  by a releasable coupling (not shown) along hatched line X shown in  FIG. 2 . 
     In order to address various issues and advance the art, the entirety of this disclosure shows by way of illustration various embodiments in which that which is claimed may be practiced and provide for a superior electronic cigarette. The advantages and features of the disclosure are of a representative sample of embodiments only, and are not exhaustive and/or exclusive. They are presented only to assist in understanding and teach the claimed features. It is to be understood that advantages, embodiments, examples, functions, features, structures, and/or other aspects of the disclosure are not to be considered limitations on the disclosure as defined by the claims or limitations on equivalents to the claims, and that other embodiments may be utilized and modifications may be made without departing from the scope and/or spirit of the disclosure. Various embodiments may suitably comprise, consist of, or consist essentially of, various combinations of the disclosed elements, components, features, parts, steps, means, etc. In addition, the disclosure includes other inventions not presently claimed, but which may be claimed in future.