Patent Publication Number: US-2022232892-A1

Title: Inhaler and replaceable liquid reservoir for an inhaler

Description:
The present invention relates to an inhaler having the features of the preamble of claim  1  and to a replaceable liquid reservoir for an inhaler having the features of the preamble of claim  7 . 
     Such inhalers with a receptacle for a replaceable liquid reservoir are known, for example, as electronic cigarette products. 
     The inhalers comprise a vaporizer device with at least one electric vaporizer for vaporizing liquid supplied to the vaporizer, at least one electrical line for supplying the vaporizer with electric current, and a receptacle for retaining a replaceable liquid reservoir which can be fluidically connected to the vaporizer via an opening. 
     Conventional electronic cigarette products or inhalers comprise a vaporizer device based, for example, on wick-coil technology, in which the liquid is transported by capillary forces from the liquid reservoir along a wick until the liquid is heated by an electrically heatable coil and thus vaporized. The wick serves as a liquid-conducting connection between the liquid reservoir and the heating coil, which serves as the vaporizer. 
     One disadvantage of wick-coil technology is that a lack of liquid supply leads to local overheating, which can produce pollutants. This so-called “dry puff” must be avoided. In addition, such vaporizer devices are often leaky due to the manufacturing process, so that liquid can escape in undesirable ways, for example via the air supply and/or vapor discharge. 
     To avoid the problems of wick-coil technology, DE 10 2017 111 119 A1 describes a vaporizer device with a vaporizer in which liquid is transported from the liquid reservoir by a wick structure to an inlet side of the vaporizer by capillary forces. The vaporizer vaporizes the liquid, and the vaporized liquid can be added to an air stream as a vapor and/or aerosol. The vaporizer is electrically connectable to an energy storage device via an electrical line for the supply of electrical energy. 
     In this context, the invention is based on the task of providing an inhaler and a replaceable liquid reservoir for an inhaler, in which unintentional escape of the liquid is reliably prevented, or is reduced to the lowest possible level. 
     The invention solves the task with the features of the independent claims. 
     According to claim  1 , for solving the task an inhaler comprising a vaporizer device with at least one electric vaporizer for vaporizing liquid supplied to the vaporizer, at least one electrical line to an electrical voltage supply of the vaporizer, and a receptacle for retaining a replaceable liquid reservoir, which is fluidically connectable to the vaporizer via an opening, is proposed, wherein according to the basic idea of the invention it is proposed that the receptacle comprises means which force the replaceable liquid reservoir with the opening into direct abutment with the vaporizer. 
     With the proposed solution, the liquid reservoir with the opening is in direct contact with the vaporizer without a formation of a gap, and the liquid inevitably exits through the vaporizer when exiting the liquid reservoir. Further, when the liquid exits, the liquid is directly vaporized in the vaporizer, so that the vaporization is realized with a very good overall efficiency and the lowest possible losses. 
     It is further proposed that a seal sealing the opening to the outside is provided between the vaporizer and the liquid reservoir. The provided seal can further reduce the likelihood of accidental leakage of the liquid from the vaporizer device without passing through the vaporizer in the process. In this regard, the seal encloses the contact area between the vaporizer device and the opening of the liquid reservoir through which the liquid passes from the liquid reservoir into the vaporizer device, such that the seal prevents lateral escape of the liquid or vapor at the surface from the vaporizer device. In this regard, the seal may be provided on both the liquid reservoir and the vaporizer. However, an arrangement on the liquid reservoir has the advantage that it is immediately replaced with a new seal when the liquid reservoir is changed. 
     In this context, the device can preferably comprise a clamping device actuated by magnetic force, which enables reversible release and replacement of the liquid reservoir, in particular without the use of a tool. 
     Further, the device may alternatively or also additionally comprise a spring-loaded pressing piece which is spring-loaded in the direction such that it forces the replaceable liquid reservoir against the vaporizer. 
     It is further proposed that the pressing piece is spring-loaded in the direction of an intended flow direction in the inhaler. The intended direction of flow is defined by the flow of air caused in the inhaler when the consumer draws on the mouthpiece according to the intended use, thereby creating a negative pressure in the inhaler. Due to the proposed direction of the spring loading, it is in the same direction as the pressure gradient generated during drawing, so that the pressure force acting between the liquid reservoir and the vaporizer during drawing can be increased and the tendency of the liquid reservoir to detach from the vaporizer can be counteracted. 
     It is further proposed that the pressing piece is spring-loaded point-symmetrically with respect to its longitudinal axis. Due to the point-symmetrical spring loading, the liquid reservoir is forced against the vaporizer with a compressive force that is distributed as uniformly as possible over the circumference. 
     Further, to solve the problem according to claim  7 , a replaceable liquid reservoir for an inhaler with a hollow space, which is filled with at least one liquid and is releasable via an opening, and a wick structure for transporting the liquid out of the hollow space, is proposed, in which the opening is enclosed by a seal, and is closed via a foil bonded to the seal. 
     The proposed solution can reduce or prevent accidental leakage of the liquid both before the liquid reservoir is inserted into the inhaler and when the liquid reservoir is inserted. In this regard, the seal is specifically used, prior to insertion, for bonding the foil sealing the opening and, in the inserted state, for sealing the contact zone between the opening of the liquid reservoir and the vaporizer. 
     It is further proposed that the wick structure in the liquid reservoir is formed by a sponge filling at least the opening. The sponge forms a wick through its capillaries, which causes the liquid to be conveyed from the hollow space through the opening towards the vaporizer, wherein the sponge enables the liquid to be supplied independently of the position and orientation of the inhaler by the regularly repeated filling of the capillary and the liquid to be completely emptied from the hollow space. 
     This also allows the sponge to completely fill the hollow space so that the liquid is stored exclusively in the capillaries. In addition, this allows a low pressure to be applied to the sponge in the inserted state via the abutting vaporizer, without allowing the sponge to escape into the hollow space. Through this pressure, the liquid can again be actively sucked in similar to the principle of felt pens, wherein the liquid is safely stored in the sponge in the case that no pressure is exerted. 
     This exertion of pressure can be effected by drawing on the inhaler or also by a spring-loaded receptacle in the inhaler. 
     Further, the sponge may preferably be flexible in itself so that it can adjust slightly to the geometry and irregularities of a mating surface such as a vaporizer when inserted into a vaporizer device. This can avoid voids and improve the transfer of liquid from the liquid reservoir to, for example, a vaporizer. Furthermore, the advantageous pressure described above can thereby be converted into a compression of the sponge, by which the suction and onward transport of the liquid is further facilitated. 
     It is further proposed that the sponge is thermally stable up to a temperature of 300° C. The proposed material property prevents the material from melting under the effect of temperature and the capillaries from melting down. Furthermore, it can prevent components of the sponge from outgassing and being added to the liquid to be vaporized. 
     The invention is explained below on the basis of preferred embodiments with reference to the accompanying figures. Thereby shows 
    
    
     
         FIG. 1  a schematic view of an inhaler; 
         FIG. 2  a perspective section through a schematic vaporizer-tank unit; 
         FIG. 3  a replaceable liquid reservoir as an individual part; 
         FIG. 4  an enlarged view of a vaporizer tank unit with a replaceable liquid reservoir. 
     
    
    
       FIG. 1  schematically shows an inhaler  10  or an electronic cigarette product. The inhaler  10  comprises a housing  11  in which an air channel  30  or vent is provided between at least one air inlet opening  231  and an air outlet opening  24  at a mouth end  32  of the cigarette product  10 . The mouth end  32  of the inhaler  10  thereby denotes the end at which the consumer draws for the purpose of inhalation, thereby applying a negative pressure to the inhaler  10  and generating an air flow  34  in the air channel  30 . 
     Advantageously, the inhaler  10  comprises a base part  16  and a vaporizer tank unit  20  that comprises a vaporizer device  1  having a vaporizer  60  and a liquid reservoir  18 , which is in particular in the form of a replaceable interchangeable cartridge. The liquid reservoir  18  can be replaced by the user of the inhaler  10 , for which purpose the inhaler  10  comprises a suitable closable access opening  2 . The air drawn through the air inlet opening  231  is directed in the air channel  30  to the at least one vaporizer  60 . The vaporizer  60  is connected or connectable to the liquid reservoir  18 , in which at least one liquid  50  is stored. For this purpose, a porous and/or capillary liquid-conducting wick structure  19  is advantageously arranged at an inlet side  61  of the vaporizer  60 . 
     The vaporizer  60  vaporizes liquid  50  supplied to the vaporizer  60  from the liquid reservoir  18  by the wick structure  19  by means of capillary forces, and adds the vaporized liquid as an aerosol/vapor to the air stream  34  at an outlet side  64 . 
     The electronic cigarette  10  further comprises an electrical energy storage device  14  and an electronic control device  15 . The energy storage device  14  is generally disposed in the base part  16  and may be, in particular, a disposable electrochemical battery or a rechargeable electrochemical battery, for example, a lithium-ion battery. The vaporizer tank unit  20  is disposed between the energy storage device  14  and the mouth end  32 . The electronic control device  15  comprises at least one digital data processing device, in particular microprocessor and/or microcontroller, in the base part  16  (as shown in  FIG. 1 ) and/or in the vaporizer tank unit  20 . 
     Advantageously, a sensor, for example a pressure sensor or a pressure or flow switch, is arranged in the housing  11 , wherein the control device  15  can determine, based on a sensor signal output by the sensor, that a consumer is drawing on the mouth end  32  of the cigarette product  10  to inhale. In this case, the control device  15  controls the vaporizer  60  to add liquid  50  from the liquid reservoir  18  as an aerosol/vapor into the air stream  34 . 
     The at least one vaporizer  60  is arranged in a portion of the vaporizer tank unit  20  facing away from the mouth end  32 . This allows for effective electrical coupling and control of the vaporizer  60 , particularly with the base part  16 . Advantageously, the air flow  34  passes through an air channel  30  extending axially through the liquid reservoir  18  to the air outlet opening  24 . 
     The liquid  50  stored in the liquid reservoir  18  to be dispensed is, for example, a mixture of 1,2-propylene glycol, glycerol, water and preferably at least one aroma (flavor) and/or at least one active ingredient, in particular nicotine. However, the indicated components of the liquid  50  are not mandatory. In particular, aroma and/or active ingredients, in particular nicotine, may be omitted. 
       FIG. 2  shows a perspective section through a schematic vaporizer tank unit  20 . The vaporizer tank unit  20  comprises a block-shaped, preferably monolithic heating body or vaporizer  60  preferably made of an electrically conductive material, in particular a semiconductor material, preferably silicon. It is not necessary that the entire vaporizer  60  be made of an electrically conductive material. It may be sufficient, for example, that the surface of the vaporizer  60  is electrically conductive, for example metallically coated or preferably suitably doped. In this case, the entire surface need not be coated; for example, metallic or preferably non-metallic or non-metallically laminated metallic conductor tracks may be provided on a non-conductive or semi-conductive base body. It is also not essential that the entire vaporizer  60  heats; for example, it may be sufficient if a section or heating layer of the vaporizer  60  heats in the region of the outlet side  64 . The vaporizer  60  is heated by electrical energy based on its electrical resistance, and thus may be referred to as a resistance heater. 
     Advantageously, the vaporizer  60  is provided with a plurality of microchannels or fluid channels  62  that fluidly connect an inlet side  61  of the vaporizer  60  to an outlet side  64  of the vaporizer  60 . 
     The average diameter of the liquid channels  62  is preferably in the range between 5 μm and 200 μm, further preferably in the range between 30 μm and 150 μm, still further preferably in the range between 50 μm and 100 μm. Due to these dimensions, a capillary effect is advantageously created so that liquid entering a liquid channel  62  at the inlet side  61  rises upwardly through the liquid channel  62  until the liquid channel  62  is filled with liquid. The number of liquid channels  62  is preferably in the range of four to 1000. In this way, the heat input into the liquid channels  62  can be optimized and an ensured high vaporization performance and a sufficiently large vapor outlet area can be realized. 
     The liquid channels  62  are advantageously arranged in the form of an array. The array can be in the form of a matrix with s columns and z rows, wherein s advantageously lies in the range between 2 and 50 and further advantageously lies in the range between 3 and 30 and/or z advantageously lies in the range between 2 and 50 and further advantageously lies in the range between 3 and 30. In this way, an effective and easily producible arrangement of the liquid channels  62  with ensured high vaporization performance can be realized. 
     The vaporizer tank unit  20  comprises a carrier  4  with a passage opening  104  for the liquid-conducting connection of the vaporizer  60  and a liquid reservoir  18 . The carrier  4  and the vaporizer  60  are components of a vaporizer device  1 , which realizes the electrical and mechanical connection of the vaporizer  60 . A wick structure  19  is arranged in the passage opening  104  for supplying liquid  50  to the vaporizer  60 . 
     The inlet side  61  of the vaporizer  60  is liquid-conductingly connected to the liquid reservoir  18  via the wick structure  19 . The wick structure  19  is used to passively feed liquid  50  from the liquid reservoir  18  to the vaporizer  60  by means of capillary forces. The wick structure  19  advantageously contacts the inlet side  61  of the vaporizer  60  in a planar manner and covers all liquid channels  62  of the vaporizer  60  on the inlet side. On the side opposite the vaporizer  60 , the wick structure  19  is connected to the liquid reservoir  18  in a liquid-conducting manner. 
     An advantageous volume of the liquid reservoir  18  is in the range between 0.1 ml and 5 ml, preferably between 0.5 ml and 3 ml, further preferably between 0.7 ml and 2 ml or 1.5 ml. 
     The vaporizer tank unit  20  is preferably connected and/or connectable to a heating voltage source  71  controllable by the control device  15 , which is connected to the vaporizer  60  for an electrical voltage supply via electrical lines  105   a ,  105   b  in a contact area  131  at opposite edge sections of the vaporizer  60 , so that an electrical voltage Uh generated by the heating voltage source  71  results in a current flow through the vaporizer  60 . Due to the ohmic resistance of the electrically conductive vaporizer  60 , the current flow causes heating of the vaporizer  60  and therefore vaporization of liquid contained in the liquid channels  62 . Vapor/aerosol generated in this manner escapes to the outlet side  64  from the liquid channels  62  and is mixed with the air flow  34 . More specifically, upon detecting an air flow  34  through the air channel  30  caused by drawing of the consumer, the control device  15  controls the heating voltage source  71 , wherein the liquid contained in the liquid channels  62  is driven out of the liquid channels  62  in the form of vapor/aerosol by spontaneous heating. 
     The vaporization temperature is preferably in the range between 100° C. and 400° C., more preferably between 150° C. and 350° C., even more preferably between 190° C. and 290° C. 
     Advantageously, the vaporizer  60  may be fabricated from portions of a wafer having thin film layer technology which comprises a layer thickness preferably less than or equal to 1000 μm, further preferably 750 μm, still further preferably less than or equal to 500 μm. Surfaces of the vaporizer  60  may advantageously be hydrophilic. 
     The vaporizer tank unit  20  is adjusted to dispense an amount of liquid preferably in the range between 1 μl and 20 μl, further preferably between 2 μl and 10 μl, still further preferably between 3 μl and 5 μl, typically 4 μl per puff of the consumer. Preferably, the vaporizer tank unit may be adjustable with respect to the amount of liquid/vapor per puff, i.e., from 1 s to 3 s per puff duration. 
     The drive frequency of the vaporizer  60  generated by the heating voltage source  71  is generally advantageously in the range of 1 Hz to 50 kHz, preferably in the range of 30 Hz to 30 kHz, still more advantageously in the range of 100 Hz to 25 kHz. 
     The vaporizer  60  is preferably based on MEMS technology, in particular silicon, and is therefore advantageously a micro-electro-mechanical system. 
     In  FIG. 3 , the liquid reservoir  18  is shown in an enlarged view as a single component. The liquid reservoir  18  is in the form of a replaceable interchangeable cartridge and comprises a housing  6  with a hollow space  5 , in which the liquid  50  is stored. The housing  6  further comprises an opening  25 , which is encompassed by a seal  7  and is closed via a foil  8  bonded to the seal  7 . The hollow space  5  is preferably completely filled with a sponge. However, if the hollow space  5  is not completely filled with the sponge, it is at least arranged so that it completely fills the opening  25 . The sponge comprises a plurality of capillaries which are filled with the liquid and thereby form the wick structure  19  required for supplying the liquid. The sponge is preferably inherently flexible and thermally stable up to a temperature of 300° C. 
       FIG. 4  shows the vaporizer tank unit  20  with the liquid reservoir  18  inserted. The vaporizer tank unit  20  comprises a tubular draw member  22  having an air channel  30  provided therein and a mouthpiece  26  attached thereto. Further, the vaporizer  60  is retained in the air channel  30  of the draw member  22  such that the consumer draws air through the vaporizer  60  when the mouthpiece  26  is pulled in the direction of the arrow. Further, the vaporizer tank unit  20  comprises a pressing piece  21  which comprises a receptacle  27  in which the liquid reservoir  18  is retained. The pressing piece  21  is pulled against the pulling piece  22  by two springs  23 . The two springs  23  are arranged diametrically to a longitudinal axis L of the pressing piece  21 , so that the pressing piece  21  is spring-loaded in cross-section point-symmetrically to its longitudinal axis. The pressing piece is thereby spring loaded uniformly in the direction of its longitudinal axis L toward the vaporizer  60 . Here, the spring-loaded pressing piece  21  forms a device by means of which the liquid reservoir  18  is pressed against the vaporizer  60 . Alternatively or additionally, the pressing piece  21  could also be pressed against the vaporizer  60  by a magnetic force. The only important aspect of the pressure applying device is that the liquid reservoir  18  can be removed from the receptacle  27  and reinserted without the aid of a tool, if possible. 
     The liquid reservoir  18  is sealed via the foil  8  prior to use, i.e., the liquid  50  cannot unintentionally escape or outgas from the opening  25 . To use the liquid reservoir  18 , the foil  8  is removed and the liquid reservoir  18  is inserted into the receptacle  27 , wherein insertion can be facilitated by stretching the springs  23  and enlarging the receptacle  27 . The receptacle  27  is shaped in such a way that its shape determines the insertion direction of the liquid reservoir  18 . The liquid reservoir  18  can thus only be inserted in such a way that it comes into contact with the free opening  25  and the seal  7  on the vaporizer  60 . In doing so, the sponge, due to its inherently flexible nature, allows its surface to conform to the surface of the vaporizer  60 . Furthermore, the seal  7  is also inherently flexible and is forced against the surface of the vaporizer  60  in a sealing manner by the exertion of pressure via the springs  23  so that the liquid  50  cannot escape laterally from the opening  25  without passing through the vaporizer  60 . The sponge that is the wick structure  19  is lightly forced against the vaporizer  60  by the spring loading, so that reliable contact of the wick structure  19  with the vaporizer  60  is always realized with as few voids as possible. In addition, this allows the sponge to be slightly compressed, assisting in the discharge of the liquid from the capillaries and the delivery of the liquid toward the opening  25 . The liquid reservoir  18  is thus in fluid communication with the vaporizer  60  in the inserted state, i.e., the liquid  50  can flow from the hollow space  5  of the liquid reservoir  18  into the vaporizer  60  via the opening  25 . 
     LIST OF REFERENCE SIGNS 
     
         
           1  vaporizer device 
           2  access opening 
           4  carrier 
           5  hollow space 
           6  housing 
           7  seal 
           8  foil 
           10  inhaler 
           11  housing 
           14  energy storage device 
           15  control device 
           16  base part 
           18  liquid reservoir 
           19  wick structure 
           20  vaporizer tank unit 
           21  pressing piece 
           22  pulling piece 
           23  spring 
           24  air outlet opening 
           25  opening 
           26  mouthpiece 
           27  receptable 
           30  air channel 
           32  mouth end 
           34  air flow 
           50  liquid 
           60  vaporizer 
           61  inlet side 
           62  liquid channel 
           64  outlet side 
           71  heating voltage source 
           104  passage opening 
           105   a ,  105   b  electrical lines 
           131  contact area 
           231  air inlet opening