Apparatus and method for applying liquids to sheet materials

Abstract

An apparatus for applying a liquid to a sheet material, the apparatus comprising: a nozzle for spraying a liquid onto the sheet material, the nozzle being positionable below the nozzle; and a concave shield disposed around the nozzle, the concave shield including a collection channel disposed on an inner periphery of the shield, and at least one drain hole disposed within the collection channel for draining collected liquid from the collection channel.

Description

[Technical Field]

[0001] FIELD OF THE DISCLOSURE The present disclosure relates to an apparatus and method for applying a liquid to a sheet material. More particularly, the present invention relates to an apparatus and method for applying a liquid to a sheet material and collecting the sprayed liquid. [Background technology]

[0002] In particular, for consumables in the smoking industry, sheet materials are treated with flavorings before use in the consumable. The spraying process is typically carried out in a chamber to limit contamination of nearby machinery and personnel. Irregular application of liquid to the sheet material is undesirable because it can lead to inconsistent product and discoloration of the outer material of the consumable. Applying liquid under high pressure appears to have a positive effect on the uniformity of the spray pattern. However, spraying under high pressure likely causes the formation of very small droplets, resulting in increased dispersion that contaminates the environment. This is undesirable from the perspective of surrounding machinery and personnel, as well as from the perspective of increased liquid waste.

[0003] There is a need for an apparatus and method for applying liquid to sheet materials that limits or eliminates the above-mentioned drawbacks of prior art liquid application apparatus and methods. In particular, there is a need for an apparatus and method for applying liquid to sheet materials that reduces the impact of the sprayed liquid on the environment. Summary of the Invention

[0004] According to one aspect of the present invention, there is provided an apparatus for applying a liquid to a sheet material. The apparatus is preferably an apparatus that can be used in the tobacco industry. The apparatus includes a nozzle for spraying a liquid onto a sheet material that can be disposed below the nozzle. The apparatus also includes a concave shield disposed around the nozzle, the concave shield including a collection channel disposed on an inner periphery of the shield. The collection channel is provided to collect liquid that accumulates on an inner wall of the concave shield and slide against the inner wall. At least one drain hole is disposed in the collection channel to drain the collected liquid from the collection channel.

[0005] Providing a concave shield around the nozzle can prevent droplets generated by the nozzle, such as an aerosolizer or nebulizer, from being directed toward the sheet material or dispersed into the air and not reaching the sheet material, resulting in the droplets being trapped inside the concave shield. The trapped liquid accumulates inside the concave shield and eventually flows downward along the inside of the concave shield. A collection channel on the inner periphery collects the liquid, which is then drained through one or more drainage holes. Therefore, the dispersed liquid that does not reach the sheet material is not further distributed to the environment, such as the chamber wall of the chamber where the liquid application process takes place. Contamination of other machine components or, for example, the possibility of clogging a filtration system can be prevented or reduced. Additionally, overflow of the collection channel can be prevented, and the collected liquid can be reused within the liquid application system, reducing liquid waste.

[0006] It has been discovered that by providing the apparatus described herein, a waste reduction of 50% or more can be achieved. Additionally, the amount of liquid contaminating not only the mechanical components within the liquid application device but also adjacent mechanical components is reduced, thereby reducing system downtime and further saving time and costs. In particular, downtime of liquid application devices often leads to liquid crystallization and subsequent nozzle clogging, which additionally leads to material waste and increased equipment maintenance needs. Furthermore, liquid can condense on the chamber walls and form large droplets that can fall onto the sheet material due to gravity. These liquid spots can lead to discoloration of materials in contact with the sheet material and can lead to inconsistencies in products manufactured from the sheet material. While discoloration is a visual quality issue, crystallization and droplet formation can compromise accurate and uniform liquid deposition. For example, these effects are known to cause problems in liquid application when the liquid is flavored, especially menthol. These undesirable effects can be reduced or prevented by controlling liquid capture and collection of the dispersed liquid in a controlled manner. In particular, the device according to the present invention can reduce the above-mentioned adverse effects even when using a nebulizer with a wide spray distribution and operating under high pressure to form highly volatile droplets. These types of nebulizers are preferably used due to their ability to produce a uniform spray distribution. Furthermore, the concave shield including the collection channel is a simple element and can be manufactured at low cost. Existing liquid application equipment can be equipped with a concave shield or shielding device, as further described below in this application, without requiring significant modifications to the existing application equipment.

[0007] The concave shape of the concave shield supports the direction of flow of captured and accumulated liquid downward or sideways and downward toward the periphery of the concave shield and into collection channels located at the periphery.

[0008] Preferably, the collection channel is disposed along the entire inner circumference of the shield, which allows liquid to be collected along the entire periphery of the concave shield, and most preferably, the collection channel is disposed so as to extend circumferentially along the inner circumference of the concave shield.

[0009] The collection channel may be a separate channel element attached to one or more parts forming the walls of the concave shield, preferably the collection channel is an integral part of the concave shield, and most preferably is formed by a part of the shield.

[0010] The collection channel is preferably formed by an inwardly bent periphery of the shield.

[0011] For efficient liquid collection, the liquid is guided within the collection channel to at least one drain hole, preferably by using gravity and locating the at least one drain hole at the lowest point within the collection channel.

[0012] This can be achieved by arranging the collection channels in an inclined manner around the nozzle. The concave shield can be provided in an inclined manner around the nozzle so that at least one drain hole is located in the lowest position when the shield is attached around the nozzle. Alternatively, or additionally, the collection channels themselves can be arranged in an inclined manner within the concave shield. It is preferred that the collection channels extend in an inclined manner along the periphery of the concave shield, in particular along the circumference.

[0013] The collection channels are preferably arranged around the nozzle in an angled manner so that the shield has a lowest portion, and the at least one drain hole is located in the lowest portion.

[0014] A drain conduit may be provided in at least one of the drain holes. Via the drain conduit, liquid collected in the collection channel and directed to the drain hole can be directed away from the concave shield, for example, to a liquid recycling system. The drain conduit can protect the collected liquid from environmental contamination and can deliver the collected liquid to a location away from the concave shield.

[0015] The device may include a collection reservoir, e.g., disposed away from the shield, for receiving liquid collected in and drained from the collection channel. A drain conduit, preferably provided in the at least one drain hole, extends from the at least one drain hole to the collection reservoir. A larger amount of collected liquid can be stored in the collection reservoir, allowing the liquid to be prepared for further reuse.

[0016] The collection channel may include two or more drain holes. Multiple drain holes may be advantageous when large amounts of collected liquid are drained from the collection channel. Thus, overflow of the collection channel at undesirable locations may be limited or prevented. Additionally, multiple drain holes in the collection channel may potentially compensate for clogged or blocked drain holes.

[0017] If two or more drain holes are provided in the collection channel, a drain conduit may be provided for each of the two or more drain holes. Several collection reservoirs may be provided, for example, one for each drain conduit. Preferably, several drain conduits lead to one collection reservoir. Preferably, all drain conduits extend from two or more drain holes to one collection reservoir.

[0018] In a preferred embodiment, the concave shield has a round circumference, e.g., circular or elliptical. A circular concave shield symmetrically shields droplets around the nozzle. Typically, nozzles are used that spray liquid onto the sheet material in a rotationally symmetric manner, so a rotationally symmetric concave shield for shielding the nozzle is preferred.

[0019] However, the concave shield may also have other perimeters, for example, a rectangular perimeter. Because the sheet material is generally and preferably provided as a band material that is guided through the apparatus below the nozzle, the shield may also have a rectangular configuration. A particular symmetry of the shield may also be achieved with a rectangular shape, for example, by a concave shield having a square shape.

[0020] The concave shield forms a cavity therein, the cavity being closed on one side by the top of the shield, the nozzle being disposed in an opening in the top of the shield, and the concave shield being open on the other side of the top of the shield, and therefore the cavity being open on its opposite end.

[0021] The concave shape of the shield may be continuous or discontinuous. In particular, the concave shield may include a top wall and side walls. Typically, the interface between the top wall and the side walls is not continuous. Preferably, the concave shield includes one or more continuous side walls. The interface between the side walls may be discontinuous.

[0022] The concave shield may include, for example, a dome shape, which provides an inner surface for efficiently capturing and directing liquid downward into the collection channel. The dome shape may be provided in circular and elliptical shapes, but may also be provided in, for example, a rectangular shaped concave shield.

[0023] The concave shield is preferably bell-shaped. The bell-shaped shield preferably has a circular circumference. The bell-shaped shield preferably comprises one continuous wall that forms the concave shield or at least forms the entire side wall of the concave shield.

[0024] The bell-shaped shield provided very good results in liquid capture and collection, and experiments have shown that in an apparatus for applying liquid to sheet materials, liquid waste can be significantly reduced, for example, from 1.6 percent liquid waste in an application without the bell-shaped concave shield to 0.7 percent liquid waste in an application with the bell-shaped concave shield.

[0025] The concave shield preferably comprises a curved wall portion, which allows for continuous and smooth guidance of liquid over the curved wall portion as well as deflection of accumulated liquid over the curved wall portion. The concave shield may also comprise only the curved wall portion.

[0026] Alternatively, or additionally, the concave shield may comprise a flat wall portion. The concave shield may comprise only a flat wall portion. A flat wall portion may be easier to manufacture and may be advantageous, for example, for mounting the concave shield to a nozzle.

[0027] The flat wall portion preferably forms the upper wall of the concave shield, which is preferably horizontally disposed in the installed state of the concave shield.

[0028] The flat wall portion may form a lower sidewall of the concave shield. In particular, the flat wall portion or portions may form the lowest sidewall of the concave shield or the most peripherally disposed sidewall of the concave shield.

[0029] A flat wall portion is understood herein to be flat in at least one direction, in particular in only one direction. The flat wall portion may, for example, be flat in the exact vertical or up-down direction of the concave shield in the installed state of the shield. The flat wall portion may, in particular, be flat in a first direction, and may be curved in a second direction perpendicular to the first direction, for example if the flat wall portion forms a side wall of the concave shield.

[0030] The flat wall portions are flat in a cross-sectional view of the concave shield. The flat wall portions forming the side walls are preferably vertically linear or oriented radially outward and downward in a cross-sectional view of the concave shield. For example, the concave shield may have a substantially triangular cross-sectional shape, in which the side walls of the shield represent the sides of the triangle.

[0031] The lower wall of the concave shield is generally angled or oriented more vertically than the upper wall of the concave shield. For example, the lower wall of the concave shield may be disposed at an angle between 40 degrees and 90 degrees, with 90 degrees corresponding to the vertical in the installed state of the shield. The lower wall may be disposed at an angle between 45 degrees and 90 degrees, with 90 degrees preferably corresponding to the vertical in the installed state of the shield.

[0032] Generally, the wall portion of the concave shield preferably includes a slope angle of between 4 degrees and 90 degrees, preferably between 6 degrees and 50 degrees, e.g., 7 degrees or 45 degrees, with 90 degrees corresponding to the vertical in the installed state of the shield. Thus, the slope angle is measured between horizontal and vertical.

[0033] Preferably, the majority of the wall portions of the concave shield include a slope angle of at least 30 degrees.

[0034] In a flat concave shield embodiment, the majority of the wall portion is flat and includes a slope angle of, for example, 5 to 10 degrees.

[0035] The above given ranges of tilt angles have been shown to provide concave shield shapes that provide good results in terms of liquid collection, and in particular good liquid guidance into the collection channel without large droplet formation and without the droplets accidentally dropping off before reaching the collection channel. These shapes have also provided good results in capturing dispersed droplets but not interfering with the droplet trajectories of droplets directed towards the sheet material.

[0036] The inside of the concave shield is preferably continuous, preferably continuously curved. The continuous inner wall of the concave shield supports smooth and safe guidance of the liquid into the collection channel. The continuity can prevent liquid accumulation at discontinuities on the inside of the concave shield, which can lead to the formation and fall of large droplets.

[0037] The size of the concave shield is preferably adapted to the area sprayed by the nozzle and the size of the sheet material to which the liquid is applied. The size of the concave shield is preferably such that the outer lateral extension of the concave shield is greater than the width of the sheet material to which the liquid is being applied, so that the concave shield does not interfere with the lateral extension of the nozzle's spray area.

[0038] The concave shield captures scattered droplets, especially light, highly volatile droplets that drift away from the spray direction and almost certainly will not reach the sheet material. However, the concave shield may not capture droplets that would typically reach the sheet material, especially heavy droplets.

[0039] The concave shield may also be sized such that the collection channels located at the periphery of the concave shield are at least partially located outside the sheet material, and the drain holes may therefore be located laterally outside the sheet material, so that liquid draining from the drain holes does not inadvertently spray onto the sheet material, and optional drain conduits for the drain holes do not interfere with the transport of the sheet material through the apparatus.

[0040] The concave shield may have a maximum lateral extension, preferably a diameter, of 0.10 meters to 1 meter. Preferably, the concave shield has a maximum lateral extension, preferably a diameter, of 0.15 meters to 0.7 meters, more preferably 0.2 meters to 0.5 meters.

[0041] Concave shields having a maximum lateral extension within the above size ranges have provided good results in shielding and collecting atomized liquids in the tobacco industry, particularly for sheet materials used in the manufacture of aerosol-forming substrates, such as smoking articles or heat-and-burn articles, in which tobacco or nicotine-containing substrates are heated rather than combusted.

[0042] The device may further comprise a temperature control system adapted to control the temperature of the atomized liquid. Preferably, the temperature of the liquid is controlled in an indirect manner, for example by a temperature control system adapted to control the temperature of at least one of the recessed shield, in particular the collection channel, the drain conduit if provided, and the collection reservoir if provided.

[0043] The temperature control of the liquid supports the continuous flow of the liquid and therefore the liquid application process, but may also particularly support the capture and collection of the liquid.

[0044] Temperature control may in particular prevent crystallization of the liquid and thereby prevent loss of liquid or contamination or clogging of machine parts, such as drainage channels, drainage holes or drainage conduits, as well as filtration systems or nozzles.

[0045] In some embodiments, the temperature control system is preferably adapted to control only the atomized liquid, independently of the temperature of the liquid in the nozzle. The atomization result may depend on the type of atomized liquid, in particular its viscosity, so that temperature control of the atomized liquid preferably does not interfere with the atomization process itself.

[0046] However, the temperature control system may also be adapted to control the temperature of the nozzle. Because the formation of crystals in the nozzle can reduce the atomization efficiency of the nebulizer, controlling the temperature of the nozzle can prevent or limit crystallization of the liquid in the nozzle, and therefore prevent or limit uneven distribution of the liquid on the sheet material, particularly system downtime. For example, the thermal radiation of a heated concave shield can be directed at the nozzle to heat it.

[0047] The temperature control system preferably includes a heater and a temperature sensor. The heater may be, for example, a resistive heating element. The temperature control system may include a feedback loop connected to the temperature sensor to control the heater.

[0048] The temperature control system may preferably include a cooling element for cooling the concave shield. By cooling the concave shield or a portion of the concave shield, the capture of liquid on the cooled shield wall and the crystallization of the liquid on the wall may be enhanced. Subsequent heating of the respective shield wall can re-liquefy the captured and crystallized liquid, which can then be directed into the collection channel. The cooling element may include, for example, a thermoelectric element.

[0049] The temperature control system may be adapted to perform heating and cooling cycles. For example, a cooling cycle may increase the capture of liquid by the concave shield. A subsequent, preferably short heating cycle melts the captured droplets and supports collection of the liquid.

[0050] The apparatus may further comprise vibration means for vibrating at least a portion of the concave shield. For example, by vibrating the sidewalls of the concave shield, crystallization of the trapped liquid may be limited or prevented, while flow of the trapped liquid may be supported, while gravity and the orientation of the sidewalls of the concave shield direct the trapped liquid towards the periphery of the shield and into the collection channel.

[0051] The vibration means may be provided and adapted to be more effective on the periphery of the concave shield than on the top of the concave shield.

[0052] When vibration means are provided, the concave shield and nozzle may be mechanically decoupled so that the nozzle and the atomized liquid are not affected by the vibration means.

[0053] Alternatively, vibration means may be directed at the nozzle to prevent or reduce crystallization of the liquid within the nozzle, for example the sonic vibrations of a vibrating concave shield may be directed at the nozzle to prevent or reduce crystallization within the nozzle.

[0054] To further maintain the collected liquid in a liquid state, the collection reservoir may include a stirring mechanism. Continuous movement of the liquid may prevent crystallization and keep the liquid homogeneous. Alternatively, or additionally, the collection reservoir may include a heater for heating the collection reservoir or the liquid collected in the collection reservoir.

[0055] The apparatus may further comprise a conveying device adapted to convey the sheet material past the nozzle having the concave shield. The conveying device may comprise at least one roller rotatable in the conveying direction. The roller is adapted to support the sheet material being conveyed in the conveying direction and to pass the apparatus under the nozzle.

[0056] The liquid is applied to the sheet material as it passes through the nozzle. The sheet material can be transported through the device continuously or in stages. The sheet material is preferably transported through the device continuously, preferably at a constant speed. In a continuous liquid application process, the sheet material can be provided with a uniform and consistent amount of liquid across the entire surface area of ​​the sheet material. This allows for the production of products from the sheet material with consistent and reproducible results. Furthermore, continuous operation of the spray nozzle is advantageous because it can reduce or prevent crystallization of the liquid in the nozzle and thereby clogging of the nozzle.

[0057] Preferably the nozzle is a nebulizer nozzle.

[0058] Two or more nozzles may be used, preferably arranged in series or in an array, preferably a regular array.

[0059] The device may further comprise a housing that encases the device. The housing protects the liquid application process. Additionally, the housing may prevent further environmental contamination with the sprayed liquid and prevent the spray process from being affected by environmental influences such as dirt or drafts.

[0060] According to another aspect of the present invention, providing a sheet material and a nozzle for liquid application; conveying the sheet material past the nozzle whereby liquid is applied to the sheet material by the nozzle; capturing liquid not applied to the sheet material with a concave shield disposed around the nozzle, particularly liquid sprayed by the nozzle but deflected or otherwise dispersed to the periphery; allowing the trapped liquid to accumulate and flow along the inner wall of the concave shield, preferably using gravity to cause the liquid to flow downward; collecting the trapped liquid in a collection channel disposed on the inner periphery of the concave shield; and draining the collected liquid from the collection channel through at least one drain hole disposed in the collection channel.

[0061] The method preferably includes collecting the liquid along the entire inner periphery of the shield. To maximize waste collection, the maximum area of ​​the concave shield is preferably used to capture, accumulate, and collect the liquid that is sprayed but not applied to the sheet material.

[0062] The method preferably includes designing the collection channel in an inclined manner so that the collection channel has a lowest portion and arranging at least one drain hole within the lowest portion, so that a certain amount of liquid collected throughout the collection channel can be directed to the at least one drain hole and the entire amount of liquid can be drained from the at least one drain hole at a central point.

[0063] Preferably, the method further comprises draining the collected liquid through a drain conduit into a collection reservoir. The drain conduit and collection reservoir allow for centralized collection of the liquid.

[0064] The method may include draining the collected liquid from the collection channel through a plurality of drain holes.

[0065] Preferably, the method includes flowing the trapped liquid along the continuously formed sidewall of the concave shield.

[0066] The method may include controlling the temperature of the liquid to control evaporation or crystallization of the trapped or collected liquid. These measures may facilitate waste collection and reduce the frequency of maintenance of the device.

[0067] Preferably, the method includes heating the liquid trapped or collected by the recessed shield. In particular, this may include heating the liquid on the shield sidewall, in the collection channel, in the drain conduit if provided, or in the collection reservoir if provided. Heating the trapped or collected liquid may limit or prevent crystallization of the liquid and this contamination or clogging of machine parts.

[0068] Controlling the temperature of the liquid may also include cooling the concave shield, particularly the sidewalls of the concave shield. Arranging the device components, particularly the concave shield, may promote droplet capture in specific locations intended and desired for liquid capture.

[0069] To support movement of the liquid trapped in the concave shield towards the collection channel, the method may include vibrating the concave shield.

[0070] The method may also include moving the liquid in the collection reservoir, and in particular agitating the liquid in the collection reservoir.

[0071] The liquid applied to the sheet material using the apparatus and method according to the present invention can be essentially any liquid and any sheet material, where reduced liquid waste and homogeneous liquid application are desired.

[0072] The apparatus and method are particularly suitable for liquid and sheet materials used in the tobacco industry.

[0073] Preferably, the liquid is a flavor, an aerosol former, an aerosol-enhancing compound, or nicotine.

[0074] The sheet material may be, in particular, a sheet material used in the manufacture of tobacco industry products. These products may be smoking articles or non-smoking articles, such as heat-and-burn articles or parts of such articles. For example, the sheet material may then be used in its sheet form, or may be compressed, gathered, or formed into a rod shape. The sheet material may be, for example, a tobacco-containing sheet, such as a tobacco cast leaf containing homogenized tobacco material, and an aerosol former, such as glycerin, which is formed into a sensory medium plug. The sheet material may also be a tobacco-free cellulosic aerosol-forming substrate, for example, containing nicotine or flavor. The sheet material may also be, for example, a plastic foil, such as a polylactic acid foil, which may be formed into a cooling plug. The sheet material may also be, for example, a tow material formed into a plug, such as a hollow acetate tube or plug.

[0075] The sheet material is preferably a filter material, a tobacco-containing material, a non-tobacco-containing cellulosic material, a packaging material, or a foil.

[0076] Preferably, the sheet material is acetate filter tow, polylactic acid foil, homogenized tobacco-containing sheet, hydroxypropylmethylcellulose and carboxymethylcellulose-containing sheet, wrapping paper, or tipping paper.

[0077] Preferably, the sheet material made from or containing homogenized tobacco material is a cast leaf, as described, for example, in WO 206 / 050470.

[0078] The tobacco-free cellulosic aerosol-forming substrate may in particular be a hydroxypropylmethylcellulose and carboxymethylcellulose-containing sheet, as described, for example, in WO 2022 / 248378.

[0079] The sheet material used in the apparatus and method according to the present invention is preferably provided as a continuous sheet material, for example a strip of material, however individual pieces of sheet material may also be fed to the apparatus.

[0080] The apparatus according to the invention and described herein is preferably used to carry out the methods according to the invention and described herein, and the features and advantages described in relation to the apparatus are also applicable to the methods and vice versa.

[0081] According to another aspect of the present invention, there is provided a shielding device for an apparatus according to the present invention and as described herein, the shielding device comprising a concave shield having a central opening for accommodating a spray nozzle therein, the concave shield further comprising a collection channel disposed on an inner periphery of the shield and at least one drain hole disposed within the collection channel.

[0082] The collection channel may be disposed along the entire inner circumference of the shield.

[0083] The collection channel may be disposed to extend circumferentially along the inner circumference of the concave shield.

[0084] The collection channel is preferably formed by an inwardly bent periphery of the shield.

[0085] The collection channel may extend in an inclined manner along the periphery of the shield, preferably along the circumference of the shield, such that the at least one drain hole is located at the lowest portion and the shield has the lowest portion.

[0086] A drain conduit may be provided in at least one drain hole.

[0087] The collection channel may include two or more drain holes, and a drain conduit may be provided in each of the two or more drain holes.

[0088] The concave shield may have a round circumference, for example may be circular or oval, or may have a rectangular perimeter.

[0089] The concave shield may include a dome shape.

[0090] The concave shield is preferably bell-shaped.

[0091] The concave shield may include curved wall portions or flat wall portions.

[0092] The flat wall portion may, for example, form the top wall of the concave shield, which is preferably arranged horizontally in the installed state of the concave shield.

[0093] The flat wall portion may form the lower wall of the concave shield.

[0094] The lower wall of the concave shield may be disposed at an angle of, for example, between 40 and 90 degrees, with 90 degrees corresponding to the vertical in the installed state of the shield. The lower wall may be disposed at an angle of, for example, between 45 and 90 degrees, with 90 degrees preferably corresponding to the vertical in the installed state of the shield.

[0095] In general, it is preferred that the wall portion of the concave shield include an inclination angle of, for example, 4 degrees to 90 degrees, more preferably 6 degrees to 50 degrees.

[0096] In a preferred embodiment of the concave shield, a majority of the wall portions of the concave shield include a slope angle of at least 30 degrees.

[0097] In a flat concave shield embodiment, the majority of the wall portion is flat and includes a slope angle of, for example, 5 to 10 degrees.

[0098] The concave shield may have a maximum lateral extension, preferably a diameter, for example, of 0.10 meters to 1 meter. More preferably, the concave shield has a maximum lateral extension, preferably a diameter, of 0.15 meters to 0.7 meters, even more preferably 0.2 meters to 0.5 meters.

[0099] The shielding device may comprise a temperature control system adapted to control the temperature of the recessed shield, in particular the shield sidewalls, the collection channels or the drainage conduits, if provided.

[0100] The temperature control system preferably includes a heater and a temperature sensor.

[0101] The temperature control system may include a cooling element for cooling the recessed shield.

[0102] The shielding device may comprise vibration means for vibrating at least a portion of the concave shield.

[0103] The features and advantages of the shielding device have been mentioned in connection with the device and will not be repeated.

[0104] The term "nozzle" is used to define a device part for generating a liquid spray. A nozzle is understood to be part of a nebulizer, and "nebulizer" generally refers to any device suitable for forming droplets for liquid distribution. In particular, a nebulizer can be a device for generating a liquid spray using, for example, an air jet, an atomizer, a vibrating mesh, ultrasonic vibrations, a piezoelectric element, etc. [Brief explanation of the drawings]

[0105] [Figure 1] FIG. 1 shows a flavor application system. [Figure 2] FIG. 2 shows crystallization on a liquid application system. [Figure 3] FIG. 3 illustrates the problem of liquid application on tobacco sheets. [Figure 4] FIG. 4 shows droplet formation on a liquid application chamber. [Figure 5] FIG. 5 shows a schematic diagram of an apparatus for liquid application with a bell-shaped shield. [Figure 6] FIG. 6 shows a perspective top view of another embodiment of a concave shield. [Figure 7] FIG. 7 shows the shield of FIG. 6 in a perspective cross-sectional view. [Figure 8] FIG. 8 shows another embodiment of a recessed shield. [Figure 9] FIG. 9 shows an apparatus for liquid application having a substantially flat concave shield. [Figure 10] FIG. 10 shows a flavor application chamber with an open housing. DETAILED DESCRIPTION OF THE INVENTION

[0106] The present invention is defined in the claims. However, below is provided a non-exhaustive list of non-limiting examples. Any one or more of the features of these examples may be combined with any one or more features described above, for example, with any one or more features of another example, embodiment, or aspect described herein.

[0107] Example 1: 1. An apparatus for applying a liquid to a sheet material, the apparatus comprising: a nozzle for spraying a liquid onto the sheet material, the nozzle being positionable below the nozzle; and a concave shield disposed around the nozzle, the concave shield comprising a collection channel disposed on an inner periphery of the shield, and at least one drain hole disposed in the collection channel for draining liquid collected from the collection channel.

[0108] Example 2: 2. The device of example 1, wherein the collection channel is disposed along the entire inner circumference of the shield.

[0109] Example 3: 3. The device of any one of Examples 1-2, wherein the collection channel is disposed to extend circumferentially along the inner circumference of the concave shield.

[0110] Example 4: 4. The device of any one of Examples 1 to 3, wherein the collection channel is formed by an inwardly bent periphery of the shield.

[0111] Example 5: 5. The device of any one of Examples 1 to 4, wherein the collection channel is arranged around the nozzle in an inclined manner such that at least one drain hole is located at its lowest portion and the shield has its lowest portion.

[0112] Example 6: 6. The device of any one of Examples 1 to 5, wherein a drainage conduit is provided in at least one drainage hole.

[0113] Example 7: 7. The device of any one of Examples 1 to 6, comprising a collection reservoir disposed away from the shield and configured to receive liquid collected in and discharged from the collection channel.

[0114] Example 8: 8. The device of any one of Examples 6 or 7, wherein a drainage conduit extends from the at least one drainage hole to the collection reservoir.

[0115] Example 9: 9. The device of any one of Examples 1-8, wherein the collection channel comprises two or more drainage holes.

[0116] Example 10: 10. The apparatus of example 9, wherein a drainage conduit is provided in each of the two or more drainage holes.

[0117] Example 11: The device of example 10, with reference again to example 7, wherein the drainage conduit extends from the two or more drainage holes to the collection reservoir.

[0118] Example 12: 12. The device of any one of Examples 1-11, wherein the concave shield has a round circumference, for example, is circular or oval.

[0119] Example 13: 12. The apparatus of any one of Examples 1-11, wherein the concave shield has a rectangular perimeter.

[0120] Example 14: 14. The apparatus of any one of Examples 1-13, wherein the concave shield comprises a dome shape.

[0121] Example 15: The device of any one of Examples 1 to 14, wherein the concave shield is bell-shaped.

[0122] Example 16: The device of any one of Examples 1-15, wherein the concave shield comprises a curved wall portion.

[0123] Example 17: The device of any one of Examples 1 to 16, wherein the concave shield comprises a flat wall portion.

[0124] Example 18: 18. The apparatus of example 17, wherein the flat wall portion forms the top wall of the concave shield.

[0125] Example 19: 19. The apparatus of example 18, wherein the top wall is positioned horizontally with the concave shield attached.

[0126] Example 20: 20. The device of any one of Examples 17-19, wherein the flat wall portion forms a lower wall of the concave shield.

[0127] Example 21: 21. The device of example 20, wherein the lower wall of the concave shield is disposed at an angle between 40 degrees and 90 degrees, with 90 degrees corresponding to vertical in the installed state of the shield.

[0128] Example 22: 22. The device of example 21, wherein the lower wall is disposed at an angle of 45 degrees to 90 degrees.

[0129] Example 23: 23. The device according to any one of Examples 1 to 22, wherein the wall portion of the concave shield comprises an inclination angle of between 4 degrees and 90 degrees, preferably between 6 degrees and 50 degrees, for example 7 degrees or 45 degrees.

[0130] Example 24: 24. The apparatus of any one of Examples 1-23, wherein a majority of the wall portion of the concave shield comprises a slope angle of at least 30 degrees.

[0131] Example 25: 25. The device of any one of Examples 1-24, wherein the interior of the concave shield is continuous, preferably continuously curved.

[0132] Example 26: 26. The apparatus of any one of Examples 1 to 25, wherein the concave shield has a maximum lateral extension, preferably a diameter, of 0.10 meters to 1 meter.

[0133] Example 27: 27. The apparatus of any one of Examples 1-26, wherein the concave shield has a maximum lateral extension, preferably a diameter, of 0.15 meters to 0.7 meters.

[0134] Example 28: 28. The apparatus of any one of Examples 1 to 27, comprising a temperature control system adapted to control the temperature of the atomized liquid.

[0135] Example 29: 29. The device of embodiment 28, wherein the temperature control system is adapted to control the temperature of at least one of the recessed shield, in particular the collection channel, if provided, the drainage conduit, and if provided, the collection reservoir.

[0136] Example 30: 30. The apparatus of any one of Examples 28-29, wherein the temperature control system is adapted to control the temperature of the nozzle.

[0137] Example 31: The apparatus of any one of Examples 28 to 30, wherein the temperature control system comprises a heater and a temperature sensor.

[0138] Example 32: 32. The apparatus of any one of Examples 28 to 31, wherein the temperature control system preferably comprises a cooling element for cooling the concave shield.

[0139] Example 33: 33. The apparatus of any one of Examples 1 to 32, comprising vibration means for vibrating at least a portion of the concave shield.

[0140] Example 34: The device of any one of Examples 7-33, wherein the collection reservoir comprises a stirring mechanism.

[0141] Example 35: 35. The apparatus of any one of examples 1-34, comprising a conveying device adapted to convey the sheet material past the nozzle using a concave shield.

[0142] Example 36: 36. The apparatus of example 35, wherein the conveying device comprises at least one roller rotatable in the conveying direction and adapted to support a sheet material conveyed in the conveying direction and to pass the apparatus under the nozzle.

[0143] Example 37: The device of any one of Examples 1 to 36, further comprising a housing covering the device.

[0144] Example 38: 1. A method for applying a liquid to a sheet material, comprising: providing a sheet material and a nozzle for liquid application; conveying the sheet material past the nozzle whereby liquid is applied to the sheet material by the nozzle; capturing any liquid not applied to the sheet material with a concave shield disposed around the nozzle; allowing the trapped liquid to accumulate and flow along an inner wall of the recessed shield; collecting the trapped liquid in a collection channel disposed on the inner periphery of the concave shield; and draining the collected liquid from the collection channel through at least one drain hole disposed within the collection channel.

[0145] Example 39: The method of example 38, wherein the liquid is collected along the entire inner circumference of the shield.

[0146] Example 40: 40. The method according to any one of Examples 38-39, wherein the collection channel is designed in an inclined manner to have a lowest part, and at least one drainage hole is located in the lowest part.

[0147] Example 41: 41. The method of any one of Examples 37-40, wherein the collected liquid is further drained into a collection reservoir through a drain conduit.

[0148] Example 42: 42. The method of any one of Examples 37-41, wherein the collected liquid is drained from the collection channel through a plurality of drain holes.

[0149] Example 43: 43. The method of any one of Examples 37-42, wherein the trapped liquid is allowed to flow along the continuously formed sidewall of the concave shield.

[0150] Example 44: 44. The method of any one of Examples 37-43, wherein the temperature of the trapped or collected liquid is controlled to control evaporation or crystallization of the liquid.

[0151] Example 45: The method of Example 44, wherein the liquid captured or collected by the concave shield is heated, in particular the liquid on the shield side wall, in the collection channel, in the drainage conduit if provided, or in the collection reservoir if provided.

[0152] Example 46: 46. ​​The method of any one of embodiments 44-45, wherein the concave shield, particularly the sidewall of the concave shield, is cooled.

[0153] Example 47: The method of any one of Examples 38 to 46, wherein the concave shield is vibrated.

[0154] Example 48: 48. The method of any one of Examples 38 to 47, comprising moving the liquid in the collection reservoir, in particular agitating the liquid in the collection reservoir.

[0155] Example 49: The method of any one of Examples 38-48, wherein the liquid is a flavor, an aerosol former, an aerosol-enhancing compound, or nicotine.

[0156] Example 50: 50. The method of any one of Examples 38 to 49, wherein the sheet material is a sheet material used in the manufacture of products for the tobacco industry.

[0157] Example 51: 51. The method of any one of Examples 38 to 50, wherein the sheet material is a filter material, a tobacco-containing material, a non-tobacco-containing cellulosic material, a packaging material, or a foil.

[0158] Example 52: The method of example 51, wherein the sheet material is acetate filter tow, polylactic acid foil, a homogenized tobacco-containing sheet, a hydroxypropylmethylcellulose and carboxymethylcellulose-containing sheet, wrapping paper, or tipping paper.

[0159] Example 53: The method according to any one of Examples 38 to 52, wherein the device according to any one of Examples 1 to 37 is used.

[0160] Example 54: 38. A shielding device for the apparatus of any one of Examples 1-37, the shielding device comprising a concave shield having a central opening for accommodating a spray nozzle within the central opening, the concave shield further comprising a collection channel disposed within an inner periphery of the shield and at least one drain hole disposed within the collection channel.

[0161] Example 55: 55. The shielding device of example 54, wherein the collection channel is disposed along the entire inner circumference of the shield.

[0162] Example 56: 56. The shielding device of any one of Examples 54-55, wherein the collection channel is disposed to extend circumferentially along the inner circumference of the concave shield.

[0163] Example 57: 57. The shielding device of any one of Examples 54-56, wherein the collection channel is formed by an inwardly bent periphery of the shield.

[0164] Example 58: 58. A shielding device as described in any one of Examples 54 to 57, wherein the collection channel extends in an inclined manner along the periphery of the shield, preferably along the circumference of the shield, such that at least one drainage hole is located at the lowest portion and the shield has the lowest portion.

[0165] Example 59: 59. The shielding device of any one of Examples 54-58, wherein a drainage conduit is provided in at least one drainage hole.

[0166] Example 60: 60. The shielding device of any one of Examples 54-59, wherein the collection channel comprises two or more drainage holes.

[0167] Example 61: 61. The shielding device of Example 60, wherein a drainage conduit is provided in each of the two or more drainage holes.

[0168] Example 62: 62. The shielding device of any one of Examples 54-61, wherein the concave shield has a round circumference, for example, is circular or elliptical.

[0169] Example 63: 62. The shielding device of any one of Examples 54-61, wherein the concave shield has a rectangular perimeter.

[0170] Example 64: 64. The shielding device of any one of Examples 54-63, wherein the concave shield comprises a dome shape.

[0171] Example 65: 65. The shielding device of any one of Examples 54 to 64, wherein the concave shield is bell-shaped.

[0172] Example 66: 66. The shielding device of any one of Examples 54-65, wherein the concave shield comprises a curved wall portion.

[0173] Example 67: 67. The shielding device of any one of Examples 54-66, wherein the concave shield comprises a flat wall portion.

[0174] Example 68: 68. The shielding device of example embodiment 67, wherein the flat wall portion forms an upper wall of the concave shield.

[0175] Example 69: 69. The shielding device of Example 68, wherein the top wall is positioned horizontally with the concave shield attached.

[0176] Example 70: 70. The shielding device of any one of Examples 67-69, wherein the flat wall portion forms a lower wall of the concave shield.

[0177] Example 71: 71. The shielding device of embodiment 70, wherein the lower wall of the concave shield is disposed at an angle between 40 degrees and 90 degrees, with 90 degrees corresponding to vertical when the shield is installed.

[0178] Example 72: 72. The shielding device of Example 71, wherein the lower wall is disposed at an angle of 45 degrees to 90 degrees.

[0179] Example 73: 73. The shielding device according to any one of Examples 67 to 72, wherein the wall portion of the concave shield comprises an inclination angle of 4 degrees to 90 degrees, preferably 6 degrees to 50 degrees.

[0180] Example 74: 74. The shielding device of any one of Examples 67-73, wherein a majority of the wall portion of the concave shield comprises a slope angle of at least 30 degrees.

[0181] Example 75: 75. The shielding device of any one of Examples 67 to 74, wherein the concave shield has a maximum lateral extension, preferably a diameter, of 0.10 meters to 1 meter. 76. The shielding device of any one of Examples 67 to 75, wherein the concave shield has a maximum lateral extension, preferably a diameter, of 0.15 meters to 0.7 meters.

[0182] Example 76: A shielding device according to any one of Examples 67 to 76, comprising a temperature control system adapted to control the temperature of the concave shield, in particular the collection channel or the drainage conduit, if provided.

[0183] Example 77: 78. The shielding device of Example 77, wherein the temperature control system comprises a heater and a temperature sensor.

[0184] Example 78: 79. The shielding device of any one of Examples 77-78, wherein the temperature control system includes a cooling element for cooling the concave shield.

[0185] Example 79: 80. The shielding device of any one of Examples 67 to 79, comprising a vibration means for vibrating at least a portion of the concave shield.

[0186] The embodiments will now be further described with reference to the figures.

[0187] FIG. 1 illustrates the principle of a liquid application system on a sheet material 1, for example, flavor application to a tobacco sheet.

[0188] A continuous sheet 1, e.g., cast tobacco leaf, is conveyed through rollers 20 along a conveying direction 100. The sheet 1 passes under a nozzle 60, where a liquid 3, e.g., a flavor, is sprayed onto the sheet 1. The sheet 1, now provided with a flavor coating 11, is then guided into a funnel-shaped tool 21, where the flavored sheet 1 is compressed and formed into a continuous rod.

[0189] The liquid 3 to be applied to the sheet 1 is provided in a reservoir 50. A pump 51 drives the liquid 3 from the reservoir 50 through a tube 52 to a nozzle 60 of a nebulizer 6. The nozzle 60 creates a spray 30 that is directed toward the sheet 1. Typically, gravity alone acts on the liquid spray 30 such that droplets of the spray 30 are directed toward the sheet 1. However, the spray 30 may also be pressurized to provide smaller droplets of liquid.

[0190] In Figure 2, a continuous sheet 1 is directed over a roller 20 beneath a nozzle 60. A liquid spray 30 is provided, for example, by the nozzle 60 of a nebulizer 6, spraying the liquid onto the sheet 1. In one embodiment, the sheet 1 is a homogenized tobacco sheet, in particular cast tobacco leaf. In the embodiment shown in Figure 2, the liquid is a flavor, namely menthol. Menthol is a popular flavor often used in the tobacco industry, but has a high tendency to crystallize.

[0191] As can be seen in Figure 2, the sprayed liquid crystallizes on the equipment components, particularly on and around the nozzle 60. The crystallized liquid 31 on the equipment components primarily becomes waste and is lost in the application process. Additionally, the crystallized liquid 31 can clog the nozzle 60, resulting in reduced nozzle 60 efficiency, inconsistent flavor application results, and process interruptions to perform necessary maintenance. Process interruptions also mean interruptions to the flow and static state of the liquid within the nozzle 60, which can result in further crystallization within the nozzle 60.

[0192] FIG. 3 shows a tobacco sheet 1 having a width 10 of approximately 17 cm onto which liquid 3 is sprayed unevenly. In the embodiment of FIG. 3, the liquid is sprayed with no or low pressure in a narrow spray jet distribution. As shown, more liquid is applied to the sheet 1 along a central band 35. This portion of the sheet 1 was positioned directly under the nozzle 1 as the sheet 1 was guided through the liquid application device. Additionally, larger droplets are formed that are applied to the sheet 1 in discrete spots 34. In these spots 34, the liquid concentration is too high. This can lead to inconsistent flavor release in the final product, particularly in tobacco products. This can also lead to liquid migration into the outer wrapper and "staining" of the wrapper, for example, by capillary action.

[0193] These effects can be reduced or prevented by using a nebulizer that produces a broad spray and by spraying under high pressure.

[0194] High-pressure nebulizers are preferred for liquid applications because they typically produce small droplets, which can homogenize the liquid distribution. However, small droplets are more volatile and tend to move in all directions. Therefore, many small droplets may not be available for application to the sheet 1 and may contaminate the environment.

[0195] 4 shows the effect of droplets spreading onto sheet 1 as it is transported from nebulizer 6 through application chamber 9. Droplets also move laterally and accumulate on the chamber walls. Droplets 32 so formed slide along the chamber walls (indicated by vertical arrows) and eventually fall onto sheet 1 as it passes through chamber 9 in transport direction 100. These droplets 32 may also form discrete spots 34 on sheet 1, as shown in FIG. 3, particularly with increasing amounts of liquid, such as flavors.

[0196] FIG. 5 shows a schematic cross-sectional front view of an apparatus for liquid application having a concave shield 4 in the form of a bell 40 disposed around a nozzle 60 .

[0197] A sheet 1, for example a homogenized tobacco sheet, is conveyed over a roller 20 (perpendicular to the direction of the drawing station) and passes under a nebulizer 6. A nozzle 60 of the nebulizer 6 sprays a liquid 3, for example a flavor, onto the sheet 1.

[0198] Bell 40 is positioned above nozzle 60 of the nebulizer with its upper portion 400 at the level of nebulizer body 62. Bell 40 has a central axis 150, which may also be an axis of rotation that substantially corresponds to the central axis of spray 30 of nozzle 60.

[0199] The upper portion 400 of the bell 40 is formed by downwardly curved wall portions. The walls 41 of the bell 40 are gradually curved more strongly until the lower wall portions are substantially flat or straight and parallel to the central axis 150 of the shield 4. These lower wall portions are vertically disposed in the installed state of the shield 4, as shown in FIG. 5. The shield walls 41, including the upper portion 400, are continuous and provide good droplet capture, coalescence, and particularly good downward guidance of accumulated liquid along the inner wall.

[0200] Bell 40 is placed around the nozzle 60 of the nebulizer and around the top of spray 30. Bell 40 then points downwards towards sheet 1, tightly surrounding spray 30 without obstructing the main distribution area of ​​the spray.

[0201] Some of the particles of the spray 30 travel toward the sheet 1, where they receive the desired liquid application. Other particles 33, typically more volatile particles, drift away from the direction of the sheet 1. These particles 33 eventually contact the inside of the shield wall 41 and are captured by the wall. These particles 33 accumulate on the shield wall 41 and, due to gravity, eventually slide along the inner wall of the shield toward a collection channel 42 located at the periphery 43 or bottom of the shield 4.

[0202] The collection channel 42 is formed by the inwardly and upwardly bent end regions of the shield wall. The collection channel 42 is provided with a drainage opening 420 having a drainage pipe 44, e.g., a plastic pipe, attached to the drainage opening 420. The drainage pipe 44 leads to a collection reservoir 46 in which flavor droplets 45 that do not reach the seat 1 but are captured by the concave shield 4 are collected. The collected liquid 39 can be reused directly by reintroducing the collected liquid 39 into the liquid reservoir of the nebulizer 6, or after passing through a cleaning process.

[0203] In Figure 5, the concave shield 4 is positioned above the sheet 1 so that the collection channel 42, and therefore the periphery of the shield 4, is located laterally outside the sheet 1. For example, the outer diameter of the bell 40 is about 18 cm and the width of the sheet 1 is about 17 cm.

[0204] Furthermore, the shield 4 is disposed immediately above the sheet 1, for example, at a distance of 25 cm to 40 cm, for example, about 33 cm, so that the spray 30 of the nozzle 60 is not hindered from applying the liquid onto the sheet 1, at least not to the sides of the sheet 1. Furthermore, most particles 33 of the liquid mist that would otherwise drift into the environment are collected by the shield 4.

[0205] The shield wall 41 captures most of the volatile flavor mist, reducing environmental, safety, and security concerns. Additionally, the captured liquid is directed to a collection channel 42 and then to a collection reservoir 46, from which the collected liquid 39 may be recovered and reused, thus reducing waste.

[0206] The collection of diffused droplets can also prevent the formation of large droplets on the chamber walls, as shown and described in Figure 4, thereby avoiding leakage of liquid onto the passing sheet 1. In addition, a longer operating time is ensured before the device must be shut down for a cleaning operation. Since crystallization of liquids, particularly flavors, inside the nozzle 60 occurs mainly during shutdown, i.e., when there is no flow through the nozzle 60, the provision of a concave shield 4 around the nozzle 60 also reduces crystallization inside the nozzle 60.

[0207] 6 and 7 show a circular concave shield 4, also in the shape of a bell. In the perspective view of FIG. 6, a circular flat top 400 can be seen, with an opening 48 in the center of the top 400 for accommodating a nebulizer within the opening 401. Sidewalls 49 of the shield 4 are bent downward and radially outward to connect with the top 400 of the shield. The lower portion of the sidewalls 49 are oriented straight outward and radially downward, so that the concave shield is more open than a bell-shaped shield, as shown in the embodiment of FIG. 5. Thus, the concave shield 4 shown in FIGS. 6 and 7 allows a broader spray of liquid to be applied to the sheet 1. In the cross-sectional view of FIG. 7, the inwardly bent lowest or most peripheral portion of the sidewalls 49 can be seen, forming a circumferentially extending collection channel 42. A drain hole 420 is located within the collection channel 42. A portion of the drain pipe 44 is integrally formed with the shield 4. A drain pipe can be attached to a portion of the drain pipe and lead to a collection reservoir.

[0208] The shield 4 may be attached to the nebulizer or the nozzle of the nebulizer, preferably with the drain hole 420 located at the lowest point of the shield 4. This allows any liquid collected in the collection channel 42 to flow through the collection channel to the drain hole 420.

[0209] The collection channel 42 may also be formed by the lowest portion of the sidewall 49 in an angled manner (inclined relative to a plane parallel to the plane of the flat top 400) so that the drain hole 420 is located at the lowest point within the shield. Providing the drain hole 420 at the lowest point of the collection channel helps to drain any liquid that reaches the collection channel 42.

[0210] In FIG. 8, a cross section of a concave shield 4 is shown in the form of a flat shield having only flat walls.

[0211] Nozzle 60 is disposed within opening 48 in flat top 400 of shield 4. Flat sidewalls 49 are oriented radially and downwardly at angles of approximately 45 degrees relative to flat top 400 or the horizontal, respectively. Shield 4 is preferably circular. However, the cross section shown in FIG. 8 could also pertain to a rectangular shield, with the longitudinal extension of the shield oriented perpendicular to the plane of the drawing.

[0212] The collection channels 43 are formed at the outermost periphery of the concave shield 4 .

[0213] 9 shows a liquid application device having a flat concave shield 4. The flat top 400 of the flat concave shield 4 is positioned horizontally, and the side walls 49 of the shield are flat, straight downward, and positioned perpendicular to the top 400. The diameter of the flat top 400 corresponds to the diameter of the shield 4. A drain pipe 44 is fluidly connected to a drain hole in the collection channel 43.

[0214] A continuous sheet 1 supported by two rollers 20 is positioned below a concave shield 4 and a nebulizer 6 .

[0215] Such a large flat shield 4 is preferably used with large droplets formed by the nebulizer 6. Large droplets tend to fall primarily downwards or even sideways, but eventually fall by gravity towards the sheet 1. Thus, the flat shield 4 captures only the most volatile droplets, but does not prevent droplets that would otherwise reach the sheet 1.

[0216] Figure 10 shows a liquid application device having an open chamber housing 9. In Figure 10, the recessed shield has been removed for better visibility of the individual parts of the device.

[0217] The two rollers 20 are disposed parallel to one another. The nozzle 60 is disposed above and between the rollers 20 when viewed vertically. The collection reservoir 46 is disposed below the rollers 20 within the bottom 90 of the housing 9.

[0218] For purposes of this specification and the appended claims, unless otherwise indicated, all numbers expressing amounts, quantities, percentages, and the like are understood to be modified in all instances by the term "about." Also, all ranges include the disclosed maximum and minimum values, as well as any intermediate ranges contained therein, whether or not specifically recited herein. Thus, in this context, the number A is understood as A ± 10% of A. Within this context, the number A can be considered to include values ​​that are within the typical standard error for measurement of the property that the number A modifies. In some instances, as used in the appended claims, the number A may deviate by the percentages recited above, so long as the amount by which A deviates does not materially affect the basic and novel characteristics of the claimed invention. Also, all ranges include the disclosed maximum and minimum values, as well as any intermediate ranges contained therein, whether or not specifically recited herein.

Claims

1. 1. An apparatus for applying a liquid to a sheet material, comprising: a nozzle for spraying a liquid onto a sheet material positionable below the nozzle; and a concave shield disposed around the nozzle, the concave shield comprising a collection channel disposed on an inner periphery of the shield, the collection channel disposed to extend circumferentially along the inner periphery of the concave shield, and at least one drain hole disposed in the collection channel for draining liquid collected from the collection channel.

2. The device of claim 1 , wherein the collection channel is formed by an inwardly bent periphery of the shield.

3. 3. The device according to claim 1, wherein the collection channel is arranged around the nozzle in an inclined manner such that the shield has a lowest portion, and the at least one drain hole is arranged in the lowest portion.

4. 4. The device of claim 1, further comprising a collection reservoir disposed away from the shield and disposed to receive liquid collected in and drained from the collection channel.

5. The device according to any one of claims 1 to 4, wherein the concave shield has a round circumference, for example is circular or oval.

6. The apparatus of any one of claims 1 to 5, wherein the concave shield comprises a curved wall portion.

7. The apparatus of any one of claims 1 to 6, wherein the concave shield comprises a flat wall portion.

8. 8. Apparatus according to any one of the preceding claims, wherein the wall portion of the concave shield comprises an inclination angle of between 4 degrees and 90 degrees, preferably between 6 degrees and 50 degrees, for example 7 degrees or 45 degrees.

9. The apparatus of any one of claims 1 to 8, wherein a majority of the wall portions of the concave shield include an angle of inclination of at least 30 degrees.

10. A device according to any one of the preceding claims, wherein the inside of the concave shield is continuous, preferably continuously curved.

11. Apparatus according to any one of the preceding claims, wherein the concave shield has a maximum lateral extension, preferably a diameter, of between 0.10 metres and 1 metre.

12. An apparatus according to any one of the preceding claims, comprising a temperature control system adapted to control the temperature of the atomised liquid.

13. 1. A method for applying a liquid to a sheet material, comprising: providing a sheet material and a nozzle for liquid application; conveying the sheet material past the nozzle, whereby liquid is applied to the sheet material by the nozzle; capturing any liquid not applied to the sheet material with a concave shield disposed around the nozzle; allowing trapped liquid to accumulate and flow along an inner wall of said recessed shield; collecting the trapped liquid in a collection channel disposed in the inner periphery of the concave shield along the entire inner periphery of the shield; and draining the collected liquid from the collection channel through at least one drain hole disposed within the collection channel.

14. 14. The method of claim 13, wherein the liquid is a flavor, an aerosol former, an aerosol-enhancing compound, or nicotine.

15. 13. A shielding device for an apparatus according to any one of claims 1 to 12, the shielding device comprising a concave shield having a central opening for accommodating a spray nozzle within the central opening, the concave shield further comprising a collection channel disposed on an inner periphery of the shield, the collection channel being disposed to extend circumferentially along the inner periphery of the concave shield, and at least one drain hole being disposed within the collection channel.

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