The present invention relates to a delivery system for liquid aerosol-forming substrate for use in an aerosol-generating system, such as a handheld electrically operated aerosol- generating system. The invention relates also to an aerosol-generating system comprising such delivery system and a method of generating an aerosol in an aerosol-generating system.

Handheld electrically operated aerosol-generating systems are known that consist of a device portion comprising a battery and control electronics, a cartridge portion comprising a supply of aerosol-forming substrate held in a liquid storage portion, and an electrically operated vaporiser, and a mouthpiece, from which the user inhales aerosol. The vaporiser typically comprises a coil of heater wire wound around an elongate wick soaked in the liquid aerosol- forming substrate held in the liquid storage portion.

EP 0 957 959 B1 discloses an electrically operated aerosol generator for receiving liquid material from a source, the aerosol generator comprising an electrical pump for pumping the liquid material in metered amounts from the source through a tube with an open end. A heating element is provided which surrounds the tube. The liquid material within the tube is volatilized upon activation of the heater. Upon volatilization the liquid material expands and exits the open end of the tube in gaseous form.

It would be desirable to provide an aerosol-generating system with a low-maintenance liquid delivery system and with a desirable atomization effect.

According to a first aspect of the present invention there is provided an aerosol generating system, comprising a heater assembly, and a manually operated pump. The manually operated pump defines a pumping volume having an inlet portion and an outlet portion. The inlet portion of the manually operated pump is configured to be connectable to a liquid storage portion. The outlet portion of the manually operated pump is in fluid connection with a dispensing assembly, for dispensing the liquid aerosol-forming substrate onto the heater assembly. The manually operated pump is operable to pump the liquid aerosol-forming substrate from the liquid storage portion via the dispensing assembly onto the heater assembly.

With examples of the present invention the liquid aerosol-forming substrate can be provided onto the heater assembly without the need for any electrically driven pumping system. Thus, the number of electric or electronic components, which might be prone to electromechanical malfunction, is reduced. Further, the wiring scheme of such delivery systems is less complex, such that not only maintenance, but also assembly of the aerosol-generating system is simplified.

The pumping volume of the manually operated pump may be defined by a hollow member having at least one wall, and wherein at least a portion of this wall is flexible. Alternatively, the pumping volume of the manually operated pump may be defined by a hollow member having at least one wall and a plunger moveable within the hollow member. The term "pumping volume" as used herein is defined as the internal volume of the hollow member extending between the inlet and the outlet of the hollow member. In some embodiments, the hollow member defining the pumping volume may be a hollow flexible member, such as a hollow flexible tube. Using a hollow flexible tube with its two ends forming the inlet and the outlet portion, results in a particularly simple and reliable design that may be produced in a cost-efficient manner.

The manually activated pump may comprise a volume modifier being configured to change the pumping volume of the manually operated pump. The volume modifier may be configured to be operated manually by the user. The volume modifier may comprise a moveable element that engages with the at least one flexible portion of the wall or plunger of the pumping volume. When the user operates the volume modifier, the moveable element may be pressed against the at least one flexible portion or plunger of the hollow member such that the internal volume of the hollow member is changed. When the moveable element is pressed against the at least one flexible portion or plunger of the hollow member, the internal volume of the hollow member is reduced creating an overpressure in the pumping volume. Due to this overpressure excess liquid aerosol-forming substrate contained in the pumping volume is ejected through the outlet portion of the pump volume. When the moveable element is released from the at least one flexible portion or plunger of the hollow member, the internal volume of the hollow member expands to its original size, thereby creating an underpressure in the pumping volume. Due to this underpressure liquid aerosol-forming substrate is pumped from the liquid storage portion into the pumping volume of the hollow member.

The inlet portion and the outlet portion of the hollow member of the manually operated pump may each comprise a one-way valve. The one way valve at the inlet portion of the hollow member may only allow liquid flow from a connected liquid storage portion into the pumping volume. The one-way valve at the outlet portion of the hollow member may only allow liquid flow from the pumping volume to the dispensing assembly.

Any commercially available one-way valves with adequate size and liquid flows may be used, including mini and micro flutter valves, duckbill valves, or check valves. The valves may be made for example of materials resistant to aggressive chemicals or materials which may be used for food industry and medical applications.

In an embodiment of the invention the pumping volume is defined by a hollow flexible tube having an outlet portion and an inlet portion, which are each provided with a one-way valve. The volume modifier comprises a movable element and a fixed element. The flexible tube is positioned between the fixed element and the movable element of the volume modifier, such that by moving the movable element towards the fixed element, the internal volume of the tube is reduced.

The moveable member of the volume modifier may be connected to a button provided in the housing of the aerosol-generating system, such that a user can readily operate the volume modifier.

A resilient member may be provided, which ensures that the moveable member is returned to its original position, once the user releases the volume modifier.

The size of the hollow element and its collapsible proportions during operation of the pumping unit are directly related to the volume of liquid dispensed onto the heater assembly for creation of the aerosol and may be limited to specify a maximum liquid volume per pumping pulse. In embodiments employing a flexible hollow tube, the external diameter of the tube may range from 2 to 8 millimeters, and may preferably range from 3 to 5 millimeters.

The maximum amount of liquid to be pumped as a dose for a puff may be a small volume of 0.010 to 0.060 microliters, preferably of about 0.0125 microliters.

The force and the displacement required to squeeze the hollow member of the manually operated pump are very small. The resilient member may therefore also be used in order to define a minimum required force for operating the volume modifier. This force can generally be freely chosen and may be adapted to user habits or expectations. The force may be adjusted to range between 0.1 to 1 .0 newton, and to preferably range between 0.5 to 0.8 newtons.

The displacements of the moveable member may also be freely chosen and may be adapted to the design of specific embodiments. The displacement may be adjusted to vary from 0.4. to 5.0 millimeters and may preferably vary from 0.7 to 3.0 millimeters.

The inlet portion of the manually operated pump is configured for connection to a liquid storage portion. The connection between the manually operated pump and the liquid storage portion may be a permanent connection or a releasable connection. In some embodiments the liquid storage portion may be refillable. In some embodiments the liquid storage portion may be replaceable and may be exchanged when it is empty or when the user would like to use a different type of liquid for aerosol-generation. The releasable connection between the manually operated pump and the liquid storage portion may be established by any suitable connection means, including a Luer taper connection (either the locking or fitting type).

The pump may be configured to pump liquid aerosol-forming substrates that are characterized by a relatively high viscosity as compared to water. The viscosity of a liquid aerosol-forming substrate may be in the range from about 10 to 500 millipascal seconds, preferably in the range from about 17 to 86 millipascal seconds.

At the outlet end of the dispensing assembly a nozzle may be provided via which the liquid aerosol-forming substrate may be sprayed onto the heater assembly for volatilization and aerosol creation. The nozzle converts the flow of the liquid aerosol-forming substrate into a plurality of small droplets. The spray pattern of the droplets may be adapted to the shape of the heater assembly.

The delivery device may comprise a classic type atomizer spray nozzle, in which case a flow of air is supplied through the nozzle by the action of puffing from the user, creating a pressurized air flow that will mix and act with the liquid creating an atomized spray in the outlet of the nozzle. Several systems are available on the market including nozzles that work with small volumes of liquid, in sizes that meet the requirements to fit in small portable devices. Another class of nozzle that may be used is an airless spray nozzle, sometimes referred to as a micro-spray nozzle. Such nozzles create micro spray cones in very small sizes. With this class of nozzles, the airflow management inside the device, namely inside the mouth piece, surrounds the nozzle and the heating element, flushing the heater assembly towards the outlet of the mouth piece, preferably including a turbulent air flow pattern of the aerosol exiting the mouth piece.

For either class of nozzle, the distance of the air gap between the delivery device and the sheet heater assembly facing the nozzle, is preferably within a range from 2 to 10 millimeters, more preferably from 3 to 7 millimeters. Any type of available spraying nozzles may be used. Airless nozzle 062 Minstac from manufacturer "The Lee Company" is an example of a suitable spray nozzle.

The heater assembly may comprise any type of heating element suitable for evaporating the liquid aerosol-forming substrate. The heater assembly may be substantially flat in some examples and may have any desired shape. The heater assembly for example may have a rectangular, polygonal, circular or oval shape and may have width and length dimensions of between 3 to 10 millimeters.

The heating element may comprise a thin, preferably substantially flat, electrically conductive material, such as a mesh of fibers, a conductive film, or an array of heating strips, suitable for receiving and heating an aerosol-forming substrate for use in an aerosol generating system.

The heating element may comprise a plurality of openings. For example, the heating element may comprise a mesh of fibers with interstices between them. The heating element may comprise a thin film or plate, optionally perforated with small holes. The heating element may comprise an array of narrow heating strips connected in series.

The heater assembly may comprise a heat resistive substrate and a heating element provided in the heat resistive substrate or on a surface of the heat resistive substrate. The heat resistive substrate of the heater assembly may be made from glass, heat resistive glass, ceramics, silicon, semiconductors, metals or metal alloys.

The heat resistive substrate may be substantially flat and may have any desired shape. The heat resistive substrate may have a rectangular, polygonal, circular or oval shape with for example width and length dimensions of between 3 to 10 millimeters. The thickness of the heat resistive substrate may range between 0.2 and 2.5 millimeters. In some embodiments the heat resistive substrate may be have a rectangular shape with a size of about 7 x 6 millimeters or 5 x 5 millimeters (L x W).

The heating element may be provided as a thin film coating provided to the surface of the heat resistive substrate. The heating element can be impregnated, deposited or printed the surface of the heat resistive substrate. The material of the thin film heating element can be any suitable material which has convenient electrical properties and a sufficiently high adherence to the heat resistive substrate.

The heating element may be provided within the volume of the heat resistive substrate, may be sandwiched between two elements of the heat resistive substrate or may be covered with a protective layer of heat resistive material.

In some embodiments the liquid aerosol-forming substrate may be delivered to a front side of the heat resistive substrate and the heating element may be provided on a backside of the heat resistive substrate.

The heater assembly may be spaced apart from the dispensing assembly. By providing the heater assembly spaced apart from the delivery assembly, the amount of liquid aerosol-forming substrate delivered to the heater assembly can be better controlled compared to a vaporizer having a tubing segment for carrying flow of the liquid aerosol-forming substrate from the delivery assembly to the heater assembly. Undesired capillary actions due to such tubing segment can be avoided. When passing the air gap, the delivered amount of the liquid aerosol-forming substrate will be transformed into a jet of droplets before hitting the surface of the heater assembly. Thus, a uniform distribution of the delivered amount of the liquid aerosol- forming substrate on the heater assembly can be enhanced in some examples, leading to better controllability and repeatability of generating an aerosol with a predetermined amount of vaporized aerosol-forming substrate per inhalation cycle.

The operating temperature of the heater assembly may be between 120 to 210 degrees Celsius, preferably between 150 to 180 degrees Celsius. In some examples, the operating temperature can be varied.

The aerosol-generating system may be configured such that upon activation of the pumping unit by the user, an electrical signal is generated and transmitted to the control unit. To this end the moveable member of the volume modifier may be connected to an electromechanical switch which is in electrical communication with the control unit. Activation of the pumping unit may therefore simultaneously also trigger the control unit to activate the heater assembly.

The electrical communication with the control unit can be established via corresponding wiring between the switch and the control unit. The electrical communication with the control unit may also be established via a wireless interface, such as the switch remotely sending signals to the control unit, which can for example be disposed at the other end of the device relative to the position of the switch.

The switch may be designed as kinetic self-powered electronic component. Such kinetic electronic switches do not need wiring connection to the control unit and the power source, because the required electric energy for producing and sending the signals is generated by the action of pressing the switch button. Kinetic electronic switches for single button activation of remote signals are commercially available. Applicable solutions existing in the market include very compacted, small and thin electronics, including thin film flexible electronics. Eliminating or reducing wires and electrical contacts simplifies the design and assembly of the aerosol-generating system and improves overall reliability.

The kinetic electronic component may also communicate with further surrounding devices and in particular also with further electronic components, such as sensors, used in the aerosol-generating system.

The aerosol-generating system may be an electrically operated aerosol-generating system. Preferably, the aerosol-generating system is portable. The aerosol-generating system may have a size comparable to a conventional cigar or cigarette. The aerosol-generating system may have a total length between approximately 30 millimeters and approximately 150 millimeters. The aerosol-generating system may have an external diameter between approximately 5 millimeters and approximately 30 millimeters.

According to a second aspect of the present invention there is provided a method for generating an aerosol, comprising the steps of providing a heater assembly, and providing a manually operated pump, comprising a hollow member with an inlet portion and an outlet portion. The inlet portion of the hollow member is configured to be connected to a liquid storage portion and the outlet portion of the hollow member is in fluid connection with a dispensing assembly. The method further includes operating the manually operated pump to pump a liquid aerosol-forming substrate from the liquid storage portion via the dispensing assembly onto a heater assembly.

Features described in relation to one aspect may equally be applied to other aspects of the invention.

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

Fig. 1 is a side view of an exemplary embodiment of an aerosol-generating system in standby mode;

Fig. 2 shows the delivery system of Fig. 2 during manual operation of the volume modifier; Fig. 3 shows the delivery system of Fig. 2 after manual activation of the volume modifier; and

Figure 4 is a schematic illustration of an alternative mechanism for modifying the internal volume of the hollow member.

Fig. 1 shows the components of an aerosol-generating system of the present invention in an initial or stand-by mode. The aerosol-generating system 10 comprises a housing 12, a power source 14, a control unit 16, a liquid storage portion 18, a manually operated pump 20, a dispensing assembly 22 and a heater assembly 24. The housing comprises an air inlet 26 and a mouthpiece 28 at its proximal end. In use, a user sucks or puffs at the mouthpiece creating an air stream from the air inlets 26, via the heater assembly 24 towards the mouthpiece 28.

The manually operated pump 20 is configured to collect the liquid from the liquid storage portion 18 and to pump it in a controlled way onto the heater assembly 24. The pump 20 comprises a flexible hollow tube 30, having an inlet portion 32 and an outlet portion 34, and defining a pumping volume 36 there between. At both ends of the tube 30, a one-way valve 38, 40 is provided, wherein the one-way valve 38 at the inlet portion 32 allows entry of liquid aerosol-forming substrate into the pumping volume 36 and wherein the one-way valve 40 at the outlet portion 34 allows exit of liquid aerosol-forming substrate out of the pumping volume 36. A volume modifier comprising a fixed element 44 and a moveable element 46 is provided at opposite sides of the flexible hollow tube 30. The moveable element 46 is connected to a button 48 provided in the housing 12 of the aerosol-generating system 10.

In Fig.1 the manually operated pump is depicted in the initial position in which the pumping volume is completely filled with liquid aerosol-forming substrate.

When a user presses button 48, as depicted in Fig. 2, hollow tube 30 is squeezed between moveable element 46 and fixed element 44. Thereby the pumping volume 36 is decreased and an overpressure is created in the pumping volume 36. In order to compensate the overpressure, a portion of the liquid aerosol-forming substrate is ejected through the outlet portion 34 of hollow tube 30. This is indicated by arrow 50 in Fig. 2. Outlet portion 34 is in fluid connection with dispensing assembly 22. Dispensing assembly 22 comprises a tubing 52 and a spray nozzle 54. Spray nozzle 54 is an airless spray nozzle that creates a spray cone 56 of small droplets of liquid aerosol-forming substrate that is uniformly delivered to the heater assembly 24.

Heater assembly 24 is electrically connected via wiring 58 with power source 14 and is controlled by control unit 16. Control unit 16 is in communication via wiring 60 with electrical switch 62 that is coupled to button 48. Thus, simultaneously with activating the manually operated pump via button 48, the user creates an electrical signal via electrical switch 62, whereupon control unit 16 activates heater assembly 24 for volatilization of the delivered liquid aerosol-forming substrate.

While pressing button 48 a user may draw a puff at the mouthpiece 28, creating an airstream between air inlet 26 and mouthpiece 28. The volatilized liquid aerosol-forming substrate mixes with the airstream creating an aerosol to be inhaled by the user.

When button 48 is released, as depicted in Fig. 3, the moveable element 46 is returned to its original position by resilient spring member 64. Hollow tube 30 resumes its original size creating an underpressure in the pumping volume 36. In order to compensate the underpressure, fresh liquid aerosol-forming substrate is pumped from the liquid storage portion 18 via inlet valve 38 into the pumping volume 36. This is indicated by arrow 66 in Fig. 3. In this embodiment the liquid storage portion 18 comprises a collapsing bag. The volume of the collapsing bag reduces as the liquid aerosol-forming substrate is pumped out of the liquid storage portion 18.

The embodiment described above relies on a flexible wall to allow the internal volume of the hollow member to be modified. However, other ways of modifying the volume of a hollow member are possible.

Figure 4 is a schematic illustration of an alternative mechanism for modifying the internal volume of a hollow member in a manually operated pump. The hollow member 100 comprises a rigid wall 105 containing a volume of liquid. The hollow member 100 is connected to a liquid storage portion through an inlet valve 1 10 and to a heater assembly through an outlet valve 1 15, in the manner described with reference to Figures 1 to 3. A plunger 120 is movable within the hollow member 100 and maintains a liquid tight seal with the rigid wall 105 as it moves. The internal volume 108 of the hollow member is defined between the rigid wall 105, the inlet valve 1 10, the outlet valve 1 15 and the plunger 120. Movement of the plunger within the hollow member changes the internal volume. The plunger is fixed to a button 125 that can be pressed by a user to move the plunger to move the plunger to reduce the internal volume of the hollow member. A return spring 130 is provided between the button and the rigid wall 105 to return the plunger to an initial position when the button is released. When the button is pressed by a user, liquid in the hollow member is forced out through the outlet valve 1 15 and when the button is released, the plunger returns to its initial position and liquid is drawn into the hollow member through the inlet valve 1 10.

The exemplary embodiments described above illustrate but are not limiting. In view of the above discussed exemplary embodiments, other embodiments consistent with the above exemplary embodiment will now be apparent to one of ordinary skill in the art.