ELECTRONIC CIGARETTE

[0001] 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.

[0002] Embodiments relate to an electronic cigarette.

[0003] 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.

[0004] 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.

[0005] 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.

[0006] 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.

[0007] 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.

[0015] 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.

[0016] 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.

[0017] The housing 2 contains a battery 8, sensor circuitry 9 and a vaporizer 10 that produces a vapor to be supplied to the user.

[0018] 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 14a,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 11a. 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 11a of the tube 11 towards both its inlet end 12 and outlet end 13. In this example, fibers 15a extending out of side opening 14a are wound in a spiral towards the outlet end 13 and fibers 15b extending out of side opening 14b are wound in a spiral towards the inlet end 12, with the same hand as fibers 15a. However, other winding patterns can be used. For example as shown in FIG. 5B, the fibers 15a, 15b are both wound in a spiral pattern towards the outlet end 13 of the tube 11, with opposite hands.

[0019] Other winding patterns can be used such as a serpentine pattern around the outer surface 11a of tube 11. Also the fibers 15a and/or 15b 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.

[0020] The wrapping of the fibers 15 around the outer surface 11a of the tube improves the operation of the vaporizer 10, as will be explained in more detail hereinafter.

[0021] An electrical heater coil 16 extends diametrically across the tube 11, with the wicking fibers 15 passing axially within the coil 16. Electrical leads 17a, 17b supply electrical power to the coil 16 from the battery 8 under the control of the sensor circuitry 9 shown in FIG. 2.

[0022] 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.

[0023] 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 t0 the wicking fibers 15 so that the liquid is wicked along the core of the heater coil 16.

[0024] 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.

[0025] Spigot 23 includes a through hole to provide an air inlet passageway 23a into the tube 11.

[0026] 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.

[0027] 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.

[0028] An advantage of winding the fibers 15a, 15b around the outer surface 11a 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.

[0029] 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 17a, 17b. The tubular housing 2 thus is relatively rigid to the touch of the user'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.

[0030] 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.

[0031] 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.

[0032] 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 17a, 17b 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.

[0033] 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.

[0034] 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.

[0035] 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 15b 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.

[0036] 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.

[0037] 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.