Filters for tobacco products

Abstract

Filters (1) for tobacco products, with a filter body (2) comprising a tubular mantle body (3) radially surrounding a filling of filter material (5), where the mantle body (3) has a cylindrical inner circumference (9) and a substantially conical outer circumference (10) and is formed from a planar cutout (4).

Description

[0001] The invention relates to a filter for tobacco products, comprising a filter body which has a tubular outer body radially surrounding a filling of filter material.

[0002] Such filters are known in various designs and can either be pre-installed in smoking products, such as cigarettes, or be provided as loose filters for use by the end consumer in the customer's own manufacturing of the smoking product. The present invention relates in particular to the latter loose filters.

[0003] Such filters typically have a cylindrical shape, especially with a constant diameter along their entire length. Accordingly, these filters usually have a circular diameter. Filters with a conical outer shape are also known. Such conical filters are typically made from a solid material and do not have a separate outer shell.

[0004] In solid-material filters, the entire filter body typically consists of a single filter material. Filter bodies are also known that have a sleeve body in which the filter material is contained or arranged internally. Such sleeve bodies are typically designed as a cylindrical tube with end caps. The filter material is arranged within the tube between these end caps. These end caps usually have the same diameter.

[0005] Particularly with consumer-produced smoking products, it has been shown that when using cylindrical filters and with only a slight deviation from twisting the cigarette paper straight around the filter, a gap can form between the filter and the cigarette paper, which is often undesirable and can lead to a reduced or completely absent filtering effect.

[0006] Furthermore, it has been shown that the manufacturing effort, especially for conical filters and their shaping, as well as the correct alignment of conical filters during factory insertion in the production of smoke products, is considerable, and such filters are therefore still relatively complicated and costly in their manufacture and further processing, especially in handling.

[0007] From WO 2020 / 200808 A1, a filter for an aerosol-generating object is known. The filter has a tubular outer body radially surrounding a filling of filter material. The outer body has a cylindrical inner circumference in sections, namely in the region of a first axial end, and a conically tapered outer circumference, namely in the region of the other, second axial end. However, such a conical filter is relatively complex and expensive to manufacture.

[0008] US patent 2008 / 0137792 discloses a hand-rolled cigarette with a wound filter. The filter is wrapped in cigarette paper, which surrounds the tobacco strand of the cigarette. The outer diameter of the cigarette widens in an area adjacent to the filter. The filter itself is not conical.

[0009] German patent DE 1 268 417 B discloses a filter for cigars, comprising a frustoconical plastic housing part with a cylindrical bore into which a cylindrical filter element can be inserted. However, such a conical filter comprises a large number of components and is therefore relatively complex and expensive to manufacture, as well as relatively complicated to handle.

[0010] From DE 10 2017 005 510 A1, a filter for a water pipe is known, wherein in a particular embodiment the filter can comprise a conical plastic sleeve. Here too, the filter comprises a large number of individual components, which makes its manufacture relatively complex and expensive.

[0011] German patent DE 10 2018 075 U1 discloses a trapezoidal cigarette paper sheet whose edges are not parallel to each other. When a cigarette is made with this cigarette paper, the two longitudinal edges overlap over a length of constant width, giving the cigarette a conical shape.

[0012] The object of the present invention is therefore to provide a filter for tobacco products which is improved with regard to at least one of the aforementioned disadvantages, and in particular enables uncomplicated application and cost-effective production.

[0013] The invention solves the stated problem by means of a filter with the features of the main claim. Advantageous embodiments and further developments of the invention are disclosed in the dependent claims, the description, and the figures.

[0014] According to the invention, the outer body, which is formed separately, radially surrounds the filter material filling and has a cylindrical inner circumference and a substantially conical outer circumference along its longitudinal axis. It is formed from a flat blank, particularly a paper blank. Specifically, the outer body has a cylindrical inner shape and a substantially conical outer shape. This ensures consistent filter effectiveness, especially even with cigarette paper produced by the end user that is not perfectly twisted.Furthermore, a first, preferred embodiment enables particularly cost-effective manufacturing by first producing the casing body and then attaching a closing element to a first axial end of the casing body. Next, filter material is introduced into the interior space surrounded by the casing body from a second axial end, and finally, to complete the filter, the interior volume is closed by attaching a second closing element to a second axial end. Since the casing body has a cylindrical interior shape, the first and second closing elements can be identical, which minimizes manufacturing effort. In another conceivable embodiment, where the filter material is dimensionally stable and cylindrical, for example,If the filter body is made of a porous material, it can be formed by directly applying the outer casing radially around the filter material, thereby creating the conical outer shape of the filter. In this way, a cylindrical filter body can be given a conical outer shape in a particularly simple manner by applying the casing directly around the filter material filling and, optionally, around two end elements.

[0015] Typically, the axial end of the conical filter body, hereinafter also referred to as the first axial end, which has the comparatively smaller outer diameter, is located on the axial side facing the end user or smoker, and the other axial end of the filter, hereinafter also referred to as the second axial end, which has the comparatively larger outer diameter, is located on the axial side of the filter facing away from the end user.

[0016] The filter body can have a total length between 10 mm and 40 mm, preferably between 20 mm and 30 mm, and particularly preferably about 25 mm. The filter body can, in particular, have a length corresponding to the length of the entire filter. The outer diameter of the filter body can vary along its longitudinal extent, for example, between 5 mm and 8 mm, and in particular increase in an axial direction. Preferably, the diameter of the filter body at the first axial end is about 6 mm and at the second axial end is about 7 mm. The filter body is preferably formed exclusively by the casing body and the two end caps.

[0017] The filter material is located in an interior space formed between the inner circumference of the filter body and the two optional end elements. These end elements are designed to be air-permeable and may also be dimensionally stable. For example, the end elements may be made of ceramic. Both end elements of a filter can have the same construction and design, including identical dimensions.

[0018] The outer casing is relatively thin-walled, allowing the filter body to be designed as a tube. In particular, the casing's thickness in the radial direction is significantly less than the overall diameter of the filter. This radial thickness of the casing varies along the filter's length. Specifically, the casing is thinner at the first axial end of the filter than at the second. For example, the thickness of the casing is approximately 0.11 mm at the first end and approximately 0.6 mm at the second. The casing can be constructed in layers, at least in sections, along the filter's length, particularly towards the outer circumference. The increasing thickness of the casing along the filter's length can therefore be achieved by layers of varying thickness along their length.For example, the casing material at the first axial end can consist of only a single layer, while at the second axial end it can consist of several radially stacked layers. In particular, the number of layers of the casing material can increase stepwise and / or essentially continuously from the first axial end to the second axial end. This allows the casing body to have a cylindrical shape on its inner circumference and a conical shape on its outer circumference.

[0019] The filter material can be, for example, granular and / or porous. In particular, the filter material can consist of activated carbon or contain activated carbon components.

[0020] The smoking material may contain or be composed of plant components, such as tobacco. The smoking material may also contain medically active substances. While activated carbon filters can remove a significant portion of harmful substances from inhaled smoke, a large number of medically active substances can still pass through the filter.

[0021] Preferably, the outer casing is formed by winding a blank into a rigid sleeve to accommodate the filter material within its interior. This enables effective filtration and particularly cost-effective filter production. The blank can be a thin, flat body, for example, made of paper. The outer casing can also be at least partially, and preferably completely, wrapped around the filter material filling.

[0022] Particularly preferably, the outer casing is arranged or wound in a way that overlaps at least partially, especially overlapping itself. At the beginning of the winding, the casing can extend over essentially the entire length of the filter body. The casing can abut the end elements and / or the filter material filling and, as the windings progress, be arranged to overlap itself, particularly with increasing overlap. This allows the overall thickness of the casing to be increased radially along the longitudinal extent of the filter body in a particularly simple manner, so that the casing acquires an overall conical shape due to the increasingly overlapping windings along the longitudinal extent of the filter.

[0023] The outer casing is preferably formed from a paper blank. This provides a material particularly suitable for the lateral, especially radial, sealing of the filter material, ensures a precise and snug fit of the casing to the outer surfaces of the filter, particularly at the axial ends, and allows for cost-effective filter production. The paper blank can, for example, be produced as a section or piece of a paper strip. The paper blank preferably has a total length between 80 mm and 300 mm, preferably between 100 mm and 200 mm, and most preferably around 150 mm, especially for the overlapping wrapping around the filter material filling and the optionally provided sealing elements. The paper blank or paper strip preferably has a width that corresponds to the length of the filter body.Thus, the paper blank can be precisely aligned with the filter material filling and the optional end elements along its broad side and wrapped around the filter material filling in the circumferential direction of the filter body to be formed. The paper thickness is preferably approximately 0.11 mm. This allows for both effective filtration and an aesthetically pleasing filter.

[0024] In a preferred embodiment of the invention, the paper blank comprises a first area, which is essentially rectangular in shape or corresponds to a rectangle, and a second area, which is essentially triangular in shape or corresponds to a triangle and adjoins the first area. The paper blank thus preferably extends continuously over both the first and second areas.

[0025] Preferably, the second area has a section on one longitudinal side, particularly on the longitudinal side opposite the rectangular area, which, when the jacket body is completely wrapped around the filter material filling and the optionally provided end elements, forms an outer circumferential surface of the jacket body, also called the visible area. The section of paper forming the visible area has a width that is preferably between 1 mm and 5 mm, more preferably between 2 mm and 4 mm, and particularly preferably about 3.5 mm. Particularly preferably, the circumferential surface of the jacket body or filter is formed exclusively by a section of paper forming the visible area. This section or visible area can be printed, in particular with a continuous print.

[0026] Preferably, the outer casing of the filter body rests against an end-face closure element of the filter with its cylindrical inner circumference in the region of at least one of the axial ends of the filter body. This allows the filter body to be given dimensional stability in a particularly simple and suitable manner, while simultaneously enabling a particularly effective filtration action.

[0027] Preferably, only the outer casing surrounds the filter material and the optional end elements. This means that the tubular part of the filter body can be formed solely by the outer casing. This allows for a filter with very few individual parts and consequently, particularly cost-effective manufacturing. Furthermore, the outer casing can be flush with the axial ends of the filter body in a particularly suitable manner, enabling a visually appealing design that is recognizable as a single unit. It can also be provided that the outer casing is connected to the end elements located at the filter body, particularly at least in one end region.The jacket body, in particular a jacket body designed as a paper blank, can be adapted in a particularly simple way to a preferred, in particular standardized, length of the filter.

[0028] Preferably, the outer casing with its cylindrical inner circumference forms the interior space for the filter material and, together with its substantially conical outer circumference, forms a circumferential outer surface of the filter body, and in particular of the entire filter. In particular, the casing can define an interior space for the filter material over almost the entire length of the filter body and may also abut the filter material filling. This allows the interior space available for the filter material to be particularly large, resulting in a particularly effective filtering action.

[0029] Particularly preferably, at least one of the axial ends of the shell body is force-fitted to an end-face closure element. In particular, the closure element can be pressed into the axial end of the shell body.

[0030] Furthermore, the outer casing can be bonded to itself—particularly preferably—by adhesive bonding, especially in the area of ​​its overlapping windings. For this purpose, adhesive can be applied to at least part of a flat side of the blank. Alternatively or additionally, adhesive can also be applied to at least one of the end elements, particularly to a radial outer surface or circumferential area of ​​the end element. This allows for particularly effective fixation of the end element to the outer casing, resulting in exceptional dimensional stability and filtration performance, as well as an aesthetically pleasing filter. Moreover, this makes the filter body particularly easy to handle during both manufacturing and use.

[0031] A method for manufacturing such a filter may be provided in which, to form a filter body with a conical outer circumference, a blank is wound increasingly overlapping towards the jacket body in the direction of one of the axial ends of the filter and bonded to itself, a closing element is preferably attached to a first of the axial ends by means of a force-fit connection, a filling of filter material is introduced into an interior enclosed by the jacket body and the closing element, and a further closing element is preferably attached to a second of the axial ends by means of a force-fit connection.

[0032] An embodiment of the invention is explained in more detail below with reference to the figures. The same reference numerals denote the same components. The figures schematically show: Fig. 1 - a side view of a filter according to the invention; Fig. 2 - a cross-sectional view of the filter according to Fig. 1; and Fig. 3 - a top view of a paper blank for the filter body.

[0033] In the Fig. 1 and Fig. Figure 2 shows an embodiment of a filter 1 according to the invention for use on smoking products, such as cigarettes. Such a filter 1 can either be installed in smoking products at the factory or provided as a loose filter for use by the end consumer for customer-side assembly of the smoking product.

[0034] The filter 1 serves, in particular, to filter out harmful substances, or at least some of them, from the smoke inhaled by a smoker. In a finished smoking product, such as a cigarette, the filter 1 is advantageously located in and surrounded by a portion of the smoking product (not shown), such as a paper blank, in the area facing the smoker. The area of ​​the smoking product (not shown) facing away from the smoker can, for example, surround tobacco.

[0035] The filter 1 has a tubular filter body 2 comprising a filling of filter material 5, a closing element 6a, 6b at each of the axial ends 7a, 7b of the filter 1 which limits the filling of filter material 5, and a outer shell body 3 which radially surrounds the filling of filter material 5. The outer shell body 3 is designed such that the filter body 2 has a conical outer shape.

[0036] As in Fig. As shown in Figure 2, the outer body 3 and the end elements 6a, 6b form a supporting structure of the filter body 2. The filter body 2 is thus advantageously dimensionally stable. The filter material 5 is arranged in an interior space 8 surrounded by the outer body 3 and the end elements 6a, 6b.

[0037] The first closing element 6a is arranged, in particular, at a first axial end 7a of the filter 1 facing the smoker, and a second closing element 6b is arranged at a second axial end 7b of the filter 1 facing away from the smoker, and in particular towards the tobacco. The closing elements 6a, 6b advantageously have holes so that they are permeable to air, at least in the axial direction of the filter 1. An interior space 8 for the filter material 5 is arranged between its two axial ends.

[0038] Filter material 5 serves to filter out harmful substances during smoking. Filter material 5 can comprise several different filter components. Particularly preferably, filter material 5 comprises activated carbon, which enables selective filtration, a feature often preferred.

[0039] To achieve particularly effective filtration, it is advantageous if the tubular part of the filter body 2 has a cylindrical shape on an inner circumference 9 facing the filter material 5 and a conical shape along the longitudinal extent of the filter 1 on an outer circumference 10 facing away from the filter material 5. In particular, it is advantageous if the outer diameter D1 of the filter 1 at the first axial end 7a of the filter 1 facing the smoker is smaller than the outer diameter D2 of the filter 1 at a second axial filter end 7b facing away from the smoker. For example, the diameter D1 is approximately 6 mm and the diameter D2 is approximately 7 mm.

[0040] According to the invention, the part of the filter body 2 that gives the filter 1 a conical outer shape, or that forms a conical outer shape of the filter 1, is realized by the jacket body 3 arranged around the filter material 5. In particular, the conical shape is achieved by a winding of the jacket body material 3 that increasingly overlaps along the longitudinal extent of the filter 1. For this purpose, the jacket body 3 is wound from a thin-surface blank 4, such as a paper blank, in particular such that the jacket body 3 has a substantially conical outer circumference or a conical circumferential surface 10 along the longitudinal extent of the filter 1.

[0041] The outer casing 3 has a substantially cylindrical shape on its inner circumference 9, particularly at the first winding. The cylindrical inner circumference 9 of the outer casing 3 abuts the first end element 6a in the region of the first axial end 7a and the second end element 6b in the region of the second axial end 7b, such that the end elements 6a and 6b are positively connected to the outer casing 3. Due in no small part to the cylindrical inner circumference 9 of the outer casing 3, both end elements 6a and 6b of the filter 1 can be identical in construction and design, and in particular, have the same dimensions. With its substantially conical outer circumference 10, the outer casing 3 forms the circumferential outer surface of the filter body 2, and in particular of the entire filter 1.

[0042] The cutout 4 can be an elongated paper strip which tapers in its longitudinal extent and is wound around itself in its longitudinal extent and is bonded together in a material-coherent manner, in particular by gluing.

[0043] One such paper blank 4 is, for example, in the Fig. 3 shown.

[0044] The paper blank 4 shown comprises a first area 4a, which in itself resembles a rectangle, and a second area 4b, which in itself resembles a triangle and adjoins the first area 4a on one side. The second area 4b has a section 4c on one long side, which, in a state where the outer body 3 is completely wrapped around the end elements 6a, 6b and the filter material filling 5, forms the outer circumferential surface 10 of the outer body 3, in particular a viewing area. This section 4c, or viewing area, is in Fig. Section 3 is marked with hatching. Section 4c may be printed, in particular with continuous printing. In the aforementioned finished state of the filter 1, the circumferential surface 10 of the casing body 3 is formed exclusively by section 4c. The paper blank 4 thus extends continuously over areas 4a and 4b, including 4c.

[0045] In the example shown, the paper blank 4 has a total length L2 of approximately 150 mm. The first section 4a extends over a length L3 of approximately 36 mm. The paper blank 4 has a width B1 of approximately 25 mm, which advantageously corresponds to the length of the filter body 2. Section 4c has a width B2 of approximately 3.5 mm.

[0046] Thus, the paper blank 4 can be wound to form the outer body 3. With the filter 1 completed, the first winding completely covers the filter material 5 with the first section 4a. During subsequent windings of the paper blank 4, particularly with the second section 4b, the windings overlap increasingly along the longitudinal axis of the filter 1, whereby the section at the first axial end 7a may also be formed without any overlap of the paper blank 4. In this way, the paper blank 4 with the second section 4b overlaps at least partially first the first section 4a and then at least partially the second section 4b with itself. Section 4c ultimately remains as the visible circumferential surface; that is, section 4c is neither covered nor overlapped.

[0047] The conical outer circumference of the filter 1 is thus formed by winding the material forming the outer body 3, in this case, in particular, the paper blank 4, such that the outer body material 3, that is, in particular, the paper blank 4, is wound with increasing overlap towards one of the axial ends, in particular towards the second axial end 7b facing away from the smoker. Specifically, the windings of the paper blank 4 overlap at least partially and increasingly along the length of the filter 1. The conical shape is thus achieved by the increasing number of windings. The overlapping part of the outer body 3 is formed in particular by the second region 4b of the paper blank 4.

[0048] The overlapping windings are preferably evenly distributed over the longitudinal extent of the filter 1, so that a uniformly increasing thickness of the outer body 3 and consequently an overall uniformly conical outer shape of the filter 1 is formed in the longitudinal extent of the filter 1.

[0049] Depending on requirements, the number of superimposed windings can be adjusted in a particularly simple manner to form a larger or smaller diameter of the filter 1 at the second end 7b, in particular by adjusting the number of windings. The latter is made possible in particular by changing the length of the second area 4b of the paper blank 4 and / or the angle at the Fig.The end of the second area 4b, shown on the right, is adjusted, in particular by being enlarged and / or reduced in size. After the formation of the outer body 3, a closing element 6a is attached, in particular by pressing it into the first axial end 7a. Subsequently, filter material 5 is filled into the interior 8, and this is then closed by another closing element 6b, which can also be pressed in. Reference symbol list: 1 filter 2 filter bodies 3 mantle bodies 4. Cutting 4a first area 4b second area Section 4c 5 filter material 6a Final element 6b Final element 7a first axial end 7b second axial end 8 Interior 9 Inner circumference 10 External circumference L1 length L2 length L3 length B1 width B2 width D1 diameter D2 diameter QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] WO 2020 / 200808 A1

[0007] US 2008 / 0137792

[0008] DE 1 268 417 B

[0009] DE 10 2017 005 510 A1

[0010] DE 10 2018 075 U1

[0011]

Claims

[1] Filters (1) for tobacco products, with a filter body (2) comprising a tubular mantle body (3) radially surrounding a filling of filter material (5), where the mantle body (3) has a cylindrical inner circumference (9) and a substantially conical outer circumference (10) and is formed from a planar cutout (4). [2] Filter (1) according to claim 1, characterized by , that the cut (4) is wound at least partially overlapping. [3] Filter (1) according to any one of the preceding claims, characterized by , that the cut (4) is a paper cut. [4] Filter (1) according to any one of the preceding claims, characterized by , that the cut (4) has a first area (4a) which is essentially rectangular and a second area (4b) which is essentially triangular and adjoins the first area (4a). [5] Filter (1) according to claim 4, characterized by , that the second area (4b) has a section (4c) on a longitudinal side which forms an outer circumferential surface (10) of the mantle body (3), in particular a visible area which may be printed. [6] Filter (1) according to any one of the preceding claims, characterized by , that the mantle body (3) in the region of an axial end (7a, 7b) of the filter body (2) rests against an end-side termination element (6a, 6b) of the filter body (2) with the cylindrical inner circumference (9). [7] Filter (1) according to any one of the preceding claims, characterized by , that the mantle body (3) with the cylindrical inner circumference (9) rests against the filling of filter material (5) and with the essentially conical outer circumference (10) forms a circumferential outer surface of the filter body (2), in particular of the entire filter (1). [8] Filter (1) according to any one of the preceding claims, characterized by, that the mantle body (3) is force-fitted to at least one end element (6a, 6b) of the filter body (2) and / or at least partially materially bonded to itself.

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