Electromagnetic detector for detecting characteristics of tobacco industry products

Abstract

An electromagnetic detector (1) for detecting one or more characteristics of a semi-finished product, for example a capsule of a rod-shaped article (3) in the tobacco field, of a product (2) is proposed, the electromagnetic detector (1) comprising a detection channel (4) which is open on three sides so as to allow the product (2) to pass through the detector (1) along a transport line (D), the detection channel (4) being a seat of an electromagnetic field. The electromagnetic detector (1) comprises a hollow body (5) made of a conductive material and having an interruption configured to define the detection channel (4), and a dielectric structure (601, 602) housed in the body (5) and made of a non-conductive material and configured to at least partially cover the detection channel (4). The dielectric structure (601, 602) comprises at least one first component (601) having a first dielectric constant and at least one second component (602) having a second dielectric constant. The first dielectric constant and the second dielectric constant are different from each other, preferably the first dielectric constant is smaller than the second dielectric constant.

Description

Technical Field

[0001] The present invention relates to an electromagnetic detector for detecting one or more characteristics of a product, for example, an additional element contained in a rod-shaped article such as a cigarette or a filter in the tobacco industry, or a semi-finished product of the tobacco industry intended to be packaged, for example.

[0002] In particular, the present invention aims to manufacture an electromagnetic detector that is a seat of an electromagnetic field, and the electromagnetic detector is provided with a detection channel that is open on three sides so as to allow the product to pass through the electromagnetic detector itself along a conveying line.

[0003] The rod-shaped article containing an additional element whose characteristics must be detected may be made of a fibrous material, and in the present text, the term fibrous material means a material containing fibers that can be selected from the group consisting of tobacco and cellulose acetate. In fact, the article may be, for example, a filter piece or a continuous filter in a machine for manufacturing cigarette filters, or a piece containing tobacco, or a tobacco rod for manufacturing cigarettes, and an additional element may be contained therein.

[0004] Alternatively, the product may be a semi-finished product in the tobacco field intended to be packaged, containing tobacco particles, which can be held by a suction belt. In this case, the detection channel may be configured to slidably receive at least a part of the suction belt and at least a part of the semi-finished product held by the suction belt along the conveying line.

Background Art

[0005] Cigarettes containing flavoring substances that consumers can decide whether to activate during use have been widely circulated in the market recently. These flavoring substances (such as menthol) may be in liquid form and are contained in one or more mechanically destructible capsules placed in the filter. Consumers can crush the capsules contained in the filter immediately before smoking each cigarette to disperse the contents into the filter itself and decide whether to flavor it during use. Therefore, an additional element can be a capsule intended to be crushed during use.

[0006] It should be added that currently, it is possible to manufacture very complex cigarettes with a series of portions of various types and compositions. For this reason, generally, the term "cigarette" refers to an article for the tobacco industry with an active part intended to release the substance to be inhaled.

[0007] An additional element, one or more of whose characteristics must be detected, can in this case be a composite part with a composition different from that of the tobacco composition, or a filter in which it may be contained.

[0008] Therefore, in order to ensure that the smoking articles provided to consumers always have a predetermined quality, it is important to conduct quality checks while the rod-shaped articles are being manufactured and packaged to confirm that the products contained in the rod-shaped articles, whether they are capsules or composite parts, meet the quality requirements and satisfy the predetermined acceptance criteria.

[0009] Each product, whether it is a capsule or a composite part, must be included in the corresponding article at a reference position, which must lie within a preset longitudinal tolerance range, i.e., within the tolerance range considered along the longitudinal axis of the rod-shaped article, in order for the product to be considered present and of satisfactory quality. For example, if the capsule is in a position outside the tolerance range, or if the capsule is present in an amount less than a predetermined amount because, for example, the capsule has broken during the manufacture of a cigarette or a filter and has already completely dispersed in the article, the article must be rejected as it does not meet the required quality requirements.

[0010] Thus, in the present text, the term "characteristics of the product" means, when the product is an additional element included in a smoking article, the presence or absence of the product in the smoking article, correct quantity / correct filling, and, if necessary, breakage during the manufacture of the smoking article itself, the longitudinal position, weight, dimensions in the smoking article, and, if necessary, the materials used to manufacture the product, selected from the group consisting of these features.

[0011] In contrast, when the product is a semi-finished product in the tobacco field intended for manufacturing a tobacco rod, the term "characteristics of the product" can be understood to mean features such as density and / or moisture content so as to be able to evaluate the correct quantity of tobacco inside the semi-finished product and to ensure that the rod, and thus the final finished product obtained from that rod, is correctly manufactured.

[0012] An example of a system for checking a smoking article containing a capsule is shown in document EP2848133B1, which discloses an assembly for checking a capsule containing a liquid content in an article such as a tobacco filter, the check being carried out when the article is conveyed through a microwave detection device having at least one side inlet. The protrusion of the article housed in each cavity of the conveyor protrudes from the cavity and passes through a microwave detection area for checking the liquid content of the capsule contained in the protrusion.

[0013] The microwave detection device is a waveguide resonator, and the waveguide resonator is coupled to the transmitting antenna by the transmitting iris and further coupled to the receiving antenna by the receiving iris. In this way, in the microwave resonator, there is a microwave measurement region supplied from the transmitting iris, and the measurement region is maximum at the central part of the resonator and exits from the receiving iris.

[0014] The presence of the two irises determines the measurement sensitivity of the resonator. In fact, the distance between the two irises determines the resonance frequency of the resonator, the resonance frequency determines the quality factor of the microwave resonator, which represents the measurement sensitivity of the resonator, and thus determines the ability of the resonator to accurately determine the characteristics of the capsule in the article.

[0015] Even if the presence of the two irises enables the microwave resonator to operate at a low resonance frequency, thereby avoiding the dispersion of the electromagnetic field outside the detection channel, the two irises bring complexity to the manufacture of the microwave resonator itself. In that case, the microwave resonator is composed of three separate parts (transmitting iris, receiving iris, resonator body), and it is difficult to assemble them accurately. In fact, special attention is required for the three parts when coupling the transmitting iris to the transmitting antenna and the receiving iris to the receiving antenna in order to ensure correct measurement.

[0016] On the other hand, when there is no iris and the purpose is to operate at a low resonance frequency, the electromagnetic detector extends substantially perpendicular to both the product conveyance line and the depth of the detection channel, so it may be relatively bulky. For this reason, in a machine for manufacturing smoking articles, it is necessary to secure a considerable amount of space for the electromagnetic detector, and thus it is impossible to freely select a preferred installation position for the detector.

[0017] Document EP2965640 relates to a rotary conveyor drum for rod-shaped articles, comprising one or more measuring devices associated with the drum, each measuring device comprising a passage channel open on one side to allow passage of a portion of the rod-shaped article.

[0018] Document WO2020058868 shows an electromagnetic detector comprising an emission probe for generating an electromagnetic field and a reception probe for receiving the electromagnetic field changed by the presence of a product, the probes being arranged inside the electromagnetic detector and having an angled shape, i.e., having at least one angle.

SUMMARY OF THE INVENTION

[0019] An object of the present invention is to provide an electromagnetic detector for detecting one or more characteristics of a product, such as a capsule of a rod-shaped article or a semi-finished product intended to be packaged, which has no above-mentioned problems and is at the same time easy and inexpensive to manufacture.

[0020] Another object of the present invention is to manufacture an electromagnetic detector having limited dimensions so that it can be easily installed at any position of a machine for manufacturing rod-shaped articles in the tobacco industry.

[0021] A further object of the present invention is to provide an electromagnetic detector which is a seat of an electromagnetic field and has a detection channel open on three sides, which enables a product to be conveyed through the electromagnetic detector along a conveying line, and which can check the characteristics of the product with a high level of measurement sensitivity whether the product is a filter or a capsule contained in a cigarette or a semi-finished product intended to be packaged. All these objects and other objects are achieved by the electromagnetic detector according to the present invention described in any of the following independent claims or claims directly or indirectly dependent on the described independent claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Further features and advantages of the present invention will become more apparent from the following schematic, and thus non - limiting, description of a preferred non - limiting embodiment of the electromagnetic detector as shown in the accompanying drawings.

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

[0023] Hereinafter, the same elements are referred to using the same numbers in various figures.

[0024] FIGS. 1-10 show an electromagnetic detector 1 (hereinafter more simply referred to as the detector) for detecting one or more characteristics of a product 2 in the tobacco industry.

[0025] The product 2 can be a capsule contained in an article 3, such as a cigarette as shown in FIG. 10. Generally, the product 2 can be an additional element contained in a rod-shaped article 3 such as a cigarette or a filter in the tobacco industry, or can be a semi-finished product in the tobacco industry.

[0026] What the term "product" means has been explained in detail previously and will not be repeated here for the sake of brevity.

[0027] Accordingly, in the present text, the term "characteristics of the product" means a characteristic selected from the group consisting of the presence or absence of the product in the article 3, correct quantity / correct filling, and if necessary, breakage during the manufacture of the article 3 itself, longitudinal position in the article 3, weight, dimensions, and if necessary, the material used to manufacture the product 2, when the product 2 is an additional element contained in a smoking article 3.

[0028] When the product 2 is a semi-finished product intended to be packaged, the electromagnetic detector 1 can detect the following "characteristics of the product", i.e., for example, the weight or density of the semi-finished product before being packaged with metallized paper (or paper containing metal particles).

[0029] As already described in detail, the detector 1 according to the invention can advantageously be used in various machines of the tobacco industry and even in other automatic machines of other industrial fields which have to detect one or more characteristics of the product 2.

[0030] The detector 1 comprises a detection channel 4 which is a seat of an electromagnetic field open on three sides so as to allow the product 2 to pass through the detector 1 along the transport line D.

[0031] The electromagnetic field is changed by the presence of the product 2 in the detection channel 4 and makes it possible to detect one or more characteristics of the product 2 during the passage of the product 2.

[0032] In fact, the change in the electromagnetic field can be measured and from this measurement value it is possible to identify the characteristics of the product 2 by subsequent processing.

[0033] The detector 1 comprises a hollow body 5 made of a conductive material and having an interruption configured to define the detection channel 4. Thus, a cavity is defined inside the body.

[0034] The detector 1 comprises a dielectric structure housed inside the body 5 and made of a non-conductive material, the dielectric structure being configured to at least partially cover the detection channel 4.

[0035] The dielectric structure comprises at least one first component 601 having a first dielectric constant, for example as shown in FIG. 7, and at least one second component 602 having a second dielectric constant, for example as shown in FIG. 8.

[0036] It should be noted that the first dielectric constant of the first component and the second dielectric constant of the second component are different from each other.

[0037] Thanks to the fact that the first dielectric constant and the second dielectric constant are different, they can be selected in an appropriate way and it is possible to obtain a detector 1 having an electromagnetic field of a predetermined resonance frequency with compact dimensions.

[0038] Actually, advantageously, it is possible to use a resonance frequency of 100 MHz or more and 3 GHz or less, preferably 100 MHz or more and 2 GHz or less, more preferably 1 GHz or more and 1.9 GHz or less, preferably equal to 1.9 GHz. At this resonance frequency of the electromagnetic field, it is possible to concentrate the electromagnetic field itself inside the detection channel 4, and the merit factor and measurement sensitivity of the electromagnetic detector 1 can be increased.

[0039]

[0038] The first component 601 includes an outer portion 603 configured to at least partially cover the detection channel 4, the outer portion 603 having two side panels 603a, 603b facing each other and a rear panel 603c defining the rear surface of the detection channel 4. The rear panel 603c is disposed between the two side panels 603a, 603b. The detection channel is open on the side opposite to the rear panel 603c.

[0040] As shown in the attached FIGS. 1 to 10, the side panels 603a, 603b may be parallel to each other, and in contrast, are perpendicular to the rear panel 603c.

[0041] The first component 601 includes an inner portion 604 housed inside the main body 5.

[0042]

[0039] It should be noted that the second component 602 is completely housed inside the main body 5.

[0043] Thanks to the fact that the second component 602 is completely housed inside the main body 5 and has no portion exposed to the detection channel 4, the second component 602 can be manufactured using any dielectric material (even a dielectric material not permitted for use in food, and thus a dielectric material that cannot be used to at least partially cover the detection channel 4).

[0044] The first dielectric constant of the first component 601 made of the first dielectric material is smaller than, preferably much smaller than, the second dielectric constant of the second component 602 made of the second dielectric material.

[0045] This simplifies the selection of the second dielectric material in that it is possible to use a material having a very high dielectric constant that can concentrate the electric field in the detection channel 4 and ensure the compact dimensions of the electromagnetic detector 1 itself without being restricted to selecting one of the dielectric materials permitted for use in food.

[0046] In fact, the first dielectric material of the first component 601 must be an acceptable inert material among those intended for contact with food, and may be a plastic type of material, and may be selected from the group consisting of high density polyethylene (abbreviated as HDPE), polystyrene (abbreviated as PS), polytetrafluoroethylene (a polymer belonging to the class of perfluorocarbons abbreviated as PFC known through the trade name Teflon®), and any combination thereof as required.

[0047] In fact, the plastic materials shown above are known not to have an adverse effect on the health of consumers and not to affect the quality of the smoking articles they may come into contact with.

[0048] In contrast, the second dielectric material of the second component 602 may be selected from the group consisting of ceramic materials (e.g., aluminum oxide Al2O3, or alumina, barium titanate BaTO3), crystalline materials (e.g., aluminum oxide Al2O3 in mineral form as corundum, or sapphire), and any combination thereof as required.

[0049] Thus, the second dielectric material can have a very high dielectric constant, thereby promoting the concentration of the electromagnetic field. As a result, the detector 1 can be manufactured inexpensively with the sensitivity specifications required to detect the characteristics of the product 2.

[0050] Advantageously, the second component 602 may be received inside the inner part 604 of the first component 601.

[0051] In this case, the first component 601 may also function as a protective case for the second component 602, hold the second component 602 in place, and absorb vibrations that the detector 1 may be subject to during operation of the smoking article machine in which the detector 1 is installed.

[0052] In fact, although a part of the selectable dielectric material of the second component 602 may be fragile, thanks to the accommodation provided by the second component 602, the dielectric structure comprising the first component 601 and the second component 602 is very robust in any case.

[0053] The inner part 604 of the first component 601 comprises two separating elements 604a and 604b, which starting from the side panels 603a and 603b respectively, extend laterally, in particular vertically, and are arranged on both sides of the detection channel 4.

[0054] It should be understood that the two separating elements 604a and 604b are configured and arranged to divide the cavity of the body 5. In particular, the two separating elements 604a and 604b are configured and arranged to divide the cavity defined by the body 5 into an emission cavity 505 and a reception cavity 506.

[0055] It should be noted that each separating element 604a, 604b comprises corresponding sheets 605a and 605b configured to receive the corresponding blocks 602a and 602b of the second component 602.

[0056] In fact, the second component 602 comprises at least two blocks 602a and 602b, and each block 602a or 602b may be separate from the other block 602b or 602a, as also shown in FIGS. 8 and 9.

[0057] Alternatively, according to a variant (not shown), each block 602a or 602b may be joined to another block 602b or 602a by a connection part (not shown) configured to connect the two blocks 602a and 602b to each other, and the connection part may also be received in the first component 601, for example in a sheet made at least in part on the rear panel 603c.

[0058] It should be noted that although blocks 602a and 602b are shown as prismatic blocks, in particular blocks having the shape of a parallelepiped, they may also be formed in different shapes, for example cylindrical.

[0059] In the case shown, each sheet 605a or 605b of the corresponding separating elements 604a, 604b is defined by respective outer walls 604a' or 604b' facing each other and at least one intermediate wall 604a'', 604b'' arranged between the outer walls 604a', 604b'. The rear walls facing the intermediate walls 604a'', 604b'' may be arranged to delimit the sheets 605a and 605b on three sides in order to effectively accommodate the respective blocks 602a, 602b. According to a variant (not shown), the rear walls of the separating elements 604a, 604b do not exist and each sheet 605a and 605b is open on two sides.

[0060] According to a variant (not shown), the dielectric structure may comprise a plurality of components having respective different dielectric constants and made of respective different dielectric materials to form a composite dielectric structure.

[0061] Such a composite dielectric structure can increase the merit factor and the measurement sensitivity of the detector 1 itself.

[0062] If there are multiple components, there may be a first component 601 having an outer portion 603 configured to at least partially cover the detection channel 4, but there may be both a second component 602 that is completely housed in the main body 5 and other components.

[0063] In other words, the dielectric structure may include a first component 601 made of a first dielectric material, the first component 601 having an outer portion 603 that at least partially covers the detection channel 4 and an inner portion 604 housed in the main body 5, a second component 602, and a plurality of additional components made of respective dielectric materials different from each other, and the second component 602 and the plurality of additional components are completely housed in the main body 5, particularly completely housed in the inner portion 604 of the first component 601.

[0064] In addition or alternatively, the dielectric structure may include a first component 601 and a plurality of other components made of respective dielectric materials different from each other, and the first component 601 and those other components may be present so as to partially cover the detection channel 4.

[0065] In the latter case, the first component 601 and those other components must be made of respective inert dielectric materials that are permitted for use in food. For example, each side panel 603a, 603b may be made using two different plastic dielectric materials combined with each other.

[0066] The dielectric structure may include an inner portion 604 made only in the first component 601, and the second component 602 and a plurality of additional components made of respective dielectric materials different from each other may still be completely housed in the main body 5, particularly housed in the inner portion 604.

[0067] In one embodiment, both side panels 603a and 603b may each have a respective central zone 606 that faces each other, and the respective central zone 606 protrudes further into the detection channel 4 than the remaining zone 607 surrounding each central zone 606. The passage cross-section of the detection channel 4 between the central zones 606 is smaller than the passage cross-section between the remaining zones 607.

[0068] The side panels 603a and 603b are substantially planar in the sense that both the central zone 606 and the remaining zone 607 are planar, but each central zone 606 protrudes with respect to the remaining zone 607. The central zones 606 of both side panels 603a and 603b are parallel to each other, and the remaining zones 607 of side panels 603a and 603b are also parallel to each other.

[0069] However, since it is sufficient for the central zone 606 to be present in only one of the two side panels 603a or 603b, it is not necessary for both side panels 603a and 603b to have a central zone 606 that protrudes with respect to the remaining zone 607.

[0070] One of the two side panels 603a or 603b may have a central zone 606, and the central zone 606 protrudes further into the detection channel 4 than the remaining zone 607 surrounding the central zone 606. The other side panel 603b or 603a may be completely planar.

[0071] Also in this case, the passage cross-section of the detection channel 4 in the central zone 606 is smaller than the passage cross-section of the detection channel 4 in the remaining zone 607.

[0072] It should be noted that the distance between the product 2 and the detector 1 in the central zone 606 decreases during the passage of the product 2 in the detection channel 4. This enables an improvement in the measurement sensitivity and enables the movement of the product 2 towards the detector 1 in the central zone 606 to be promoted as much as possible.

[0073] Along the conveying line D, it should be noted that the central zone 606 has rounded or inclined edges 606a so as to facilitate the entry or discharge of the product 2 along the conveying line D. This is optional and can be advantageous in the case of products 2 such as capsules contained in elongated smoking articles 3 such as cigarettes or filters, and that section can pass through the detection channel 4 along the conveying line D as will be described in more detail below.

[0074] According to another embodiment, the electromagnetic detector 1 may comprise at least one electric field concentrator 902a or 902b, and at least one electric field concentrator 902a or 902b is associated with one of the two side panels 603a or 603b and has at least one terminal arranged along a path for conveying the product 2 in the detection channel 4 along the conveying line D.

[0075] The electric field concentrators 902a, 902b are configured to concentrate the electromagnetic field on the terminal so as to promote a further improvement in the measurement sensitivity and thus an improvement in the accuracy of the measurement itself when the product 2 is conveyed in the detection channel 4.

[0076] It should be noted that preferably the electromagnetic detector 1 comprises two electric field concentrators 902a and 902b respectively associated with the side panels 603a and 603b. For example, the terminals of each electric field concentrator 902a and 902b on the respective side panels 603a and 603b are arranged along the conveying path of the capsule 2 in the cigarette 3 so as to concentrate the electromagnetic field on the capsule 2 during the passage of the capsule 2 in the detection channel 4 and the detection of the characteristics of the capsule 2 itself, that is, along the trajectory described by the capsule 3 inside the detection channel 4.

[0077] Each of the electric field concentrators 902a, 902b is made of a conductive material, is housed in the corresponding side panels 603a, 603b, has an elongated shape, for example, a strip shape. Each of the electric field concentrators 902a, 902b is arranged transversely, particularly perpendicularly, to the transport line D. Thus, since each of the electric field concentrators 902a, 902b is housed inside the corresponding side panels 603a, 603b, it is associated with the corresponding side panels 603a, 603b. Optionally, each of the electric field concentrators 902a, 902b may be fixed to the corresponding side panels 603a, 603b.

[0078] Specifically, each of the electric field concentrators 902a, 902b may be housed in the central zone 606 of the side panels 603a, 603b, for example, along the transport line D and on the center line of the same central zone 606.

[0079] Each of the electric field concentrators 902, 903 having an elongated shape is provided with two terminals where the electromagnetic field is concentrated. One of the two terminals is near the rear panel 603c, and the other is arranged towards the opening of the detection channel 4.

[0080] Thus, advantageously, the side panels 603a, 603b may have two separate zones where the electromagnetic field can be concentrated. Thereby, when two separate capsules 2 are present in the cigarette 3 and their characteristics need to be measured, the measurement becomes easier. In fact, each of the electric field concentrators 902a, 902b may have a length equal to the longitudinal distance between the two capsules 2 in the cigarette 3 in order to concentrate the electromagnetic field along the respective transport paths of each of the capsules 2 in the cigarette 3.

[0081] It should be noted that each of the side panels 603a, 603b, specifically each central zone 606, has a respective sheet that is not a through sheet (such as shown in FIGS. 3 and 5) for housing the corresponding electric field concentrators 902a, 902b such that the outer surfaces of the corresponding electric field concentrators 902a, 902b are in the same plane as the central zone 606.

[0082] However, according to a modification example not shown in the drawings, each of the electric field concentrators 902a and 902b can even extend over the entire thickness of the side panels 603a and 603b, that is, each zone 606 may have a through-sheet, whereby each electric field concentrator accommodated therein may have an outer surface that is in the same plane as the central zone 606 and a further outer surface on the side opposite to the said outer surface and in contact with the second component 602.

[0083] In particular, the further outer surfaces of the electric field concentrators 902a and 902b can be arranged in contact with the corresponding blocks 602a and 602b inserted into the corresponding sheets 605a and 605b.

[0084] The first component 601 shown in FIG. 7 has a complex three-dimensional shape and can be produced by injection molding a first dielectric material that is a plastic material. However, advantageously, the first component 601 can even be produced by 3D printing, provided that the first dielectric material allows it. Considering that it is easy to produce the first component 601 and the second component 602 made using the two blocks 602a and 602b, the dielectric structure can be produced at low cost.

[0085] The body 5 has a rear wall 501 and a front wall 502 interrupted by the detection channel 4, which face each other and are parallel.

[0086] Considering the detection channel 4, it extends along the longitudinal axis X parallel to the transport line D.

[0087] The detector 1 has a first lateral axis Y particularly perpendicular to the longitudinal axis X that is also perpendicular to the rear wall 501, and a second lateral axis Z particularly perpendicular to both the longitudinal axis X and the first lateral axis Y.

[0088] The body 5 includes two housings 503a and 503b extending from the rear wall 501 along respective axes parallel to the first lateral axis Y.

[0089] The inner part 604 of the first component 601, which is arranged inside the body 5, divides the cavity defined by the body 5 into an emission cavity 505 provided with an emission source 701 for generating an electromagnetic field and a reception cavity 506 provided with a reception source 702 for receiving the electromagnetic field changed by the presence of the product 2 in the detection channel 4.

[0090] It should be noted that the two separation elements 604a and 604b are arranged on both sides of the detection channel 4, and each separation element 604a and 604b is accommodated in the corresponding housing 503a and 503b.

[0091] More specifically, the two separation elements 604a and 604b are aligned with each other along an axis parallel to the second lateral axis Z. Thereby, the first component is symmetric with respect to the symmetry plane perpendicular to the longitudinal axis X, but this is not essential since the two separation elements 604a and 604b can be offset with respect to the symmetry plane.

[0092] Along a line parallel to the first lateral axis Y, each separation element 604a and 604b extends from the rear wall 501 to the front wall 502 and divides the cavity into the emission cavity 505 and the reception cavity 506.

[0093] This means that the outer wall 604a' or 604b' of each separation element 604a or 604b extends from the rear wall 501 to the front wall 502, and each intermediate wall 604a'' and 604b'' is arranged in contact with the front wall 502, or rather, the part of the front wall 502 that is a part of the corresponding housing 503a or 503b, as shown in FIG. 5. In this way, each block 602a or 602b is protected from contact with the front wall 502 by interposing the intermediate walls 604a'' and 604b'', that is, the vibration that the body 5 may receive can be filtered or at least attenuated, thereby increasing the robustness of the dielectric structure.

[0094] The side panels 603a, 603b extend in respective planes parallel to each other and are also parallel to the plane X-Y defined by the longitudinal axis X and the first transverse axis Y. It should be noted that each of the electric field concentrators 902a, 902b has a longitudinal axis arranged parallel to the first transverse axis Y and is arranged on the center line of the corresponding side panels 603a, 603b.

[0095] The main body 5 may have the shape of a parallelepiped and may include, as shown in FIGS. 1 to 10, two side walls 507 that are parallel to each other, face each other, and have a "C" shape, and two end walls 508 that face each other.

[0096] It should be noted that along a line parallel to the second transverse axis Z, each of the separation elements 604a, 604b extends from the corresponding side panel 603a, 603b until it contacts the corresponding end wall 508. Therefore, both the outer walls 604a', 604b' and the intermediate walls 604a'', 604b'' extend along an axis parallel to the second transverse axis Z until they contact the end wall 508.

[0097] Alternatively, according to a modification not shown, the main body 5 may have the shape of a cylinder having a symmetry axis parallel to the first transverse axis Y.

[0098] The rear wall 501 and the front wall 502 exist, but the side walls 507 and the end walls 508 do not exist in this case, and there is a curved wall that externally defines the detector 1. What was shown previously regarding the shape of the dielectric structure still applies, but since the shapes of the separation elements 604a, 604b are different, the shape of the dielectric structure is different, and it will appropriately extend along the second transverse axis Z so as to contact the curved wall when the curved wall exists.

[0099] The emission source 701 and the reception source 702 are fixed to the rear wall 501 at positions that are transverse, particularly perpendicular, to the longitudinal axis X of the detection channel 4 and are exactly opposite to the symmetry plane. The symmetry plane is parallel to the first transverse axis Y and the second transverse axis Z.

[0100] The positions of the emission source 701 and the reception source 702 are such that the electromagnetic field is parallel to the first lateral axis Y, as will be examined in more detail below.

[0101] It should be noted that the detector 1 comprises at least one temperature sensor 801a fixed to the rear wall 501 and arranged inside the body 5 for measuring the temperature of the housing 503a or 503b.

[0102] According to a variant, the detector 1 comprises a pair of temperature sensors 801a, 801b fixed to the rear wall 501, each being arranged inside the body 5, in particular inside the corresponding housing 503a or 503b, for measuring the temperature of these housings. In fact, each housing 503a and 503b has respective openings in which the temperature sensors 801a, 801b are received.

[0103] The temperature sensor 801a, or the pair of temperature sensors 801a and 801b, if they exist, performs a temperature measurement that can correct the detection of the characteristics of the manufactured product 2 when the detected electromagnetic field is affected by the internal temperature and thus the measurement values obtained from the electromagnetic field are also affected.

[0104] The temperature sensor 801a, or the two temperature sensors 801a and 801b if they exist, are arranged at positions diametrically opposite to the emission source 701 or the reception source 702.

[0105] Advantageously, the detector 1 may comprise a heating device 802 fixed to the rear wall 501 for heating the body 5 to a preset operating temperature T.

[0106] The preset operating temperature T is, for example, a few degrees higher than the maximum temperature that the detector 1 can reach when the detector 1 is installed and used in a machine in the tobacco field. This reachable maximum temperature may depend on the outside air temperature of the factory where the tobacco field machine is installed or may be selected in an appropriate manner through the stages of training and detection of the average operating temperature.

[0107] Thanks to the heating device 802, the stability of the measurements performed by the detector 1 is ensured. Therefore, when the detected electromagnetic field is affected by the internal temperature of the detector 1 itself, the correction of the detection of the characteristics of the manufactured product 2 is avoided as much as possible.

[0108] One of the two temperature sensors 801a or 801b may be used to detect the temperature of the detector 1 for the purpose of feedback checking of the heating device 802, and the other temperature sensor 801b or 801a may be used for correction according to the measurement temperature of the detection of the characteristics of the manufactured product 2 in the presence of the two temperature sensors 801a and 801b. It should be noted that when only the temperature sensor 801a is present, the temperature sensor 801a may be used for the correction of the detection of the characteristics of the manufactured product 2, and the feedback check of the heating device 802 may optionally be entrusted to a temperature sensor integrated in the heating device 802 itself.

[0109] The detector 1 further comprises at least one mode selector made of a conductive material and fixed to the body 5 in order to remove unnecessary resonance modes of the electromagnetic field.

[0110] It can be seen that the mode selector is rod-shaped and arranged parallel to the transport line D of the detection channel 4.

[0111] As shown in FIGS. 8 and 9, each housing 503a and 503b comprises respective mode selectors 901a, 901b configured to penetrate the emission cavity 505, the inner part 604 of the first component 601, and the reception cavity 506. Therefore, the detector 1 may comprise a pair of mode selectors 901a, 901b. Each mode selector 901a, 901b also penetrates the corresponding second component 602, and the second component 602 is completely housed in the inner part 604 of the first component 601.

[0112] Specifically, each mode selector 901a or 901b is configured to penetrate the corresponding separation element 604a or 604b, and the corresponding block 602a or 602b is accommodated in the sheet 605a or 605b. In FIG. 8, each mode selector 901a or 901b is shown disassembled at the insertion position into the corresponding separation element 604a, 604b.

[0113] Therefore, it should be noted that the end of each mode selector 901a or 901b is fixed to the side wall 507 of the detector 1 at a part that is part of the housing 503a or the other housing 503b. The fixing to the side wall 507 is shown as an example in FIG. 9 with reference to the housing 503a shown as being associated with the mode selector 901a. In contrast, the mode selector 901b is shown at the insertion position into the separation element 604b as in FIG. 8.

[0114] The fixing of each mode selector 901a or 901b to the corresponding housing 503a, 503b can be performed by coupling with a screw part in a manner not shown, or by holding the sheet with a washer that closes each respective hole 509 existing in the housing 503a, 503b itself for inserting each mode selector 901a, 901b.

[0115] It should be noted that each separation element 604a or 604b is also provided with respective holes 608 to enable the insertion of the corresponding mode selector 901a or 901b. Similarly, each block 602a or 602b is provided with holes 609 so that the mode selector 901a or 901b can penetrate them.

[0116] As already shown, preferably, the detector 1 is a microwave resonator operating at a resonance frequency of 100 MHz or more and 3 GHz or less, preferably 100 MHz or more and 2 GHz or less, more preferably 1 GHz or more and 1.9 GHz or less, preferably equal to 1.8 GHz.

[0117] The microwave electromagnetic field has an electric field oriented parallel to the transport plane in which the transport line of product 2 is located, and this transport plane is defined by the longitudinal axis X and the first transverse axis Y.

[0118] In fact, as shown in FIG. 10 which shows a cylindrical article 3 for smoking such as a cigarette, since the electromagnetic field strikes the cigarette 3 itself longitudinally and avoids detecting one or more characteristics of the capsule 2 from the longitudinal position of the capsule 2 itself within the cigarette 3, it is possible to easily inspect product 2 such as a capsule contained therein.

[0119] In other words, the electric field is oriented parallel to the longitudinal axis of the cigarette 3.

[0120] When product 2 is a capsule contained in a rod-shaped article 3 for smoking such as a cigarette, it is possible to propose a device comprising the above-described detector 1 and a transport device (not shown) comprising a sheet configured to hold each article 3 to be inspected and to transport them successively perpendicular to their longitudinal axes.

[0121] In this case, the section of each article 3 containing product 2 to be inspected can protrude with respect to the transport device in order to pass through the detection channel 4 along the transport line so that the detector 1 can detect the characteristics of product 2 during its passage. The electromagnetic field of the detection channel 4 has an electric field oriented parallel to the longitudinal axis of the article 3 being transported, i.e., parallel to the longitudinal axis of the cigarette 3 being transported by the transport device.

[0122] In use, the emission source 701 and the reception source 702 each generate and receive an electromagnetic field in the detection channel 4.

[0123] Thanks to the dielectric structure comprising the first component 601 and the second component 602 each having a different dielectric constant, the second component 602 has a dielectric constant greater than that of the first component 601, and can generate an electromagnetic field with a low resonance frequency in the range of 100 MHz to 3 GHz, preferably in the range of 100 MHz to 2 GHz, more preferably in the range of 1 GHz to 1.9 GHz, preferably equal to 1.8 GHz, and can concentrate the electromagnetic field inside the detection channel 4, making it possible to increase the merit factor of the detector 1 and the measurement sensitivity of the characteristics of the product 2.

[0124] Therefore, it is possible to obtain a detector 1 with a compact size and a predetermined resonance frequency that can be easily installed without causing problems due to bulkiness in machines in the tobacco field.

[0125] It is possible to detect the characteristics of the capsule 2 present in the cigarette 3 along the transport path of the product 2 in the detection channel 4, for example, during the transport of the cigarette 3 in the transport channel 4.

[0126] Thanks to the presence of a passage cross-section of the detection channel 4 that is smaller than the remaining zone 607 between the central zones 606, the measurement sensitivity is improved, and the movement of the product 2 towards the detector 1 is promoted as much as possible in the central zone 606.

[0127] Furthermore, due to the presence of the electric field concentrator 902a or 902b, it is possible to form a concentrated electric field zone arranged along the transport path of each capsule 2, further increasing the measurement sensitivity and making it possible to increase the merit factor of the detector 1.

[0128] Despite being a composite material, the dielectric structure comprising the first component 601 and the second component 602 is robust, easy to manufacture, thereby making the detector 1 itself inexpensive.

Prior Art Documents

Patent Documents

[0129] [Patent Document 1] EP2848133B1 [Patent Document 2] EP2965640 [Patent Document 3] WO2020058868

Claims

1. An electromagnetic detector (1) for detecting one or more characteristics of a product (2), for example, a capsule of a stick-shaped article (3) in the tobacco field, or a semi-finished product in the tobacco field intended to be packaged, The electromagnetic detector (1) is equipped with a detection channel (4) that is the seat of the electromagnetic field and has openings on three sides to allow the product (2) to be transported along the transport line (D) through the detector (1), and the electromagnetic detector (1) is A hollow body (5) made of a conductive material and having an interrupted portion configured to define the detection channel (4), The system comprises a dielectric structure (601, 602) housed in the main body (5), made of a non-conductive material, and configured to at least partially cover the detection channel (4), The dielectric structure (601, 602) comprises at least one first component (601) having a first dielectric constant and at least one second component (602) having a second dielectric constant, An electromagnetic detector (1) wherein the first dielectric constant and the second dielectric constant are different from each other, and preferably the first dielectric constant is smaller than the second dielectric constant.

2. The electromagnetic detector (1) according to claim 1, wherein the first component (601) is an outer portion (603) configured to at least partially cover the detection channel (4), and comprises an outer portion (603) having two opposing side panels (603a, 603b) and a back panel (603c) defining the back of the detection channel (4), and an inner portion (604) housed inside the main body (5), and the second component (602) is completely housed inside the main body (5), and in particular housed in the inner portion (604) of the first component (601).

3. The electromagnetic detector (1) according to claim 2, wherein the inner portion (604) of the first component (601) comprises two separation elements (604a, 604b), the two separation elements (604a, 604b) extending laterally, particularly vertically, starting from their respective side panels (603a, 603b), and positioned on both sides of the detection channel (4).

4. The electromagnetic detector (1) according to claim 3, wherein the second component (602) comprises at least a pair of blocks (602a, 602b), each separating element (604a, 604b) comprises a sheet (605a, 605b) configured to accommodate the corresponding block (602a, 602b), each block (602a, 602b) being separate and distinct from the other block (602b, 602a), or each block (602a, 602b) being coupled to the other block (602b, 602a) by a connecting portion configured to connect the two blocks (602b, 602a) to each other.

5. The electromagnetic detector (1) according to any one of claims 2 to 4, wherein at least one of the two side panels (603a, 603b) has a central zone (606), the central zone (606) protrudes further into the detection channel (4) than the remaining zone (607) surrounding the central zone (606), and the passage cross-section of the detection channel (4) in the central zone (606) is smaller than the passage cross-section of the detection channel (4) in the remaining zone (607).

6. The electromagnetic detector (1) according to any one of claims 2 to 4, comprising at least one field concentrater (902a, 902b) associated with one of the two side panels (603a, 603b), wherein the at least one field concentrater (902a, 902b) has at least one terminal positioned along a path for transporting the product (2) in the detection channel along the transport line (D), and the field concentrater (902a, 902b) is configured to concentrate the electromagnetic field at the terminal.

7. comprising at least one field centrifuge (902a, 902b) associated with one of the two side panels (603a, 603b), wherein the at least one field centrifuge (902a, 902b) has at least one terminal positioned along a path for transporting the product (2) in the detection channel along the transport line (D), and the field centrifuge (902a, 902b) is configured to concentrate the electromagnetic field at the terminal, The electromagnetic detector (1) according to claim 5, wherein the electric field concentraters (902a, 902b) are made of a conductive material and housed in the side panels (603a, 603b), the electric field concentraters (902a, 902b) have an elongated shape, for example, a strip shape, and are arranged laterally, particularly perpendicular to, the transport line (D), optionally additionally, the electric field concentraters (902a, 902b) are housed in the central zone (606) of the side panels (603a, 603b), and optionally additionally, the electric field concentraters (902a, 902b) extend over the entire thickness of the side panels (603a, 603b) until they contact the second component (602).

8. The main body (5) has a front wall (502) and a rear wall (501) that are opposite to and parallel to each other and interrupted by the detection channel (4), the main body (5) comprises two housings (503a, 503b) extending from the rear wall (501), the detection channel (4) extends along a longitudinal axis (X) parallel to the transport line (D), and the electromagnetic detector (1) has a first transverse axis (Y) which is particularly perpendicular to the longitudinal axis (X) perpendicular to the rear wall (501), and the longitudinal axis (X) and the first transverse axis of the detection channel (4) The electromagnetic detector (1) according to any one of claims 1 to 4, having a second transverse axis (Z) which is particularly perpendicular to both Y, wherein the first component (601) comprises an inner portion (604) located inside the body (5), the inner portion (604) is configured to divide the cavity defined by the body (5) into an emission cavity (505) comprising an emission source (701) for generating an electromagnetic field and a receiving cavity (506) comprising a receiving source (702) for receiving an electromagnetic field altered by the presence of the product (2) in the detection channel (4).

9. The electromagnetic detector (1) according to claim 8, wherein the first component (601) comprises an outer portion (603) configured to at least partially cover the detection channel (4), the outer portion (603) comprising two opposing side panels (603a, 603b) and a back panel (603c) defining the back of the detection channel (4), and an inner portion (604) housed inside the main body (5), the inner portion (604) comprising two separation elements (604a, 604b) which extend laterally, particularly vertically, starting from each side panel (603a, 603b) and are arranged on both sides of the detection channel (4), and each separation element (604a, 604b) is housed in a corresponding housing (503a, 503b).

10. The electromagnetic detector (1) according to claim 9, wherein each separation element (604a, 604b) extends from the rear wall (501) to the front wall (502) along a line parallel to the first lateral axis (Y), dividing the cavity into the emission cavity (505) and the receiving cavity (506).

11. The electromagnetic detector (1) according to claim 9, wherein the main body (5) has the shape of a parallelepiped and comprises at least two parallel, opposing and "C"-shaped side walls (507) and two opposing end walls (508), and each separating element (604a, 604b) extends along a line parallel to the second transverse axis (Z) from the corresponding side panel (603a, 603b) to the corresponding end wall (508).

12. The electromagnetic detector (1) according to claim 8, wherein the emission source (701) and the receiving source (702) are fixed to the rear wall (501) at positions opposite to the plane of symmetry perpendicular to the longitudinal axis (X) of the detection channel (4).

13. The electromagnetic detector (1) according to claim 8, comprising at least one temperature sensor (801a) fixed to the rear wall (501) and disposed within the main body (5) for measuring the temperature of the housings (503a, 503b), or comprising two temperature sensors (801a, 801b) fixed to the rear wall (501) and disposed within the main body (5) for measuring the temperature of each of the housings (503a, 503b).

14. comprising at least one temperature sensor (801a) fixed to the rear wall (501) and disposed within the main body (5) for measuring the temperature of the housings (503a, 503b), or comprising two temperature sensors (801a, 801b) fixed to the rear wall (501) and disposed within the main body (5) for measuring the temperature of each of the housings (503a, 503b), The electromagnetic detector (1) according to claim 10, wherein the temperature sensor (801a) is positioned in a position directly opposite to the emission source (701) and the receiving source (702), or the temperature sensors (801a, 801b) are positioned in a position directly opposite to the emission source (701) and the receiving source (702).

15. The electromagnetic detector (1) according to claim 8, further comprising a heating device (802) fixed to the rear wall (501) and heating the main body (5) to a preset operating temperature T.

16. The electromagnetic detector (1) according to any one of claims 1 to 4, comprising at least one mode selector, the mode selector being made of a conductive material and fixed to the body (5) to remove unwanted resonant modes of the electromagnetic field, the mode selector being rod-shaped and positioned parallel to the transport line (D) of the detection channel (4).

17. comprising at least one mode selector, the mode selector being made of a conductive material and fixed to the body (5) to remove unwanted resonant modes of the electromagnetic field, the mode selector being rod-shaped and positioned parallel to the transport line (D) of the detection channel (4), The electromagnetic detector (1) according to claim 8, wherein each housing (503a, 503b) comprises a mode selector (901a, 901b) configured to penetrate the emission cavity (505), the inner portion (604) of the first component (601), and the receiving cavity (506), and each mode selector (901a, 901b) also penetrates a corresponding second component (602), the second component (602) being fully housed in the inner portion (604) of the first component (601).

18. comprising at least one mode selector, the mode selector being made of a conductive material and fixed to the body (5) to remove unwanted resonant modes of the electromagnetic field, the mode selector being rod-shaped and positioned parallel to the transport line (D) of the detection channel (4), Each housing (503a, 503b) comprises a mode selector (901a, 901b) configured to penetrate the emission cavity (505), the inner portion (604) of the first component (601), and the receiving cavity (506), and each mode selector (901a, 901b) also penetrates a corresponding second component (602), the second component (602) being fully housed in the inner portion (604) of the first component (601), The electromagnetic detector (1) according to claim 9, wherein the second component (602) comprises a pair of blocks (602a, 602b), each separation element (604a, 604b) comprises each sheet (605a, 605b) configured to accommodate the corresponding blocks (602a, 602b), and each mode selector (901a, 901b) penetrates the corresponding separation element (604a, 604b) and the blocks (602a, 602b) housed therein.

19. The electromagnetic detector (1) is a microwave resonator operating at a resonant frequency equal to 100 MHz or more and 3 GHz or less, preferably 100 MHz or more and 2 GHz or less, more preferably 1 GHz or more and 1.9 GHz or less, preferably equal to 1.8 GHz, and the electromagnetic field has an electric field oriented parallel to the transport plane on which the transport line (D) of the product (2) is located, according to any one of claims 1 to 4.

20. The electromagnetic detector (1) according to any one of claims 1 to 4, wherein the first component (601) is made of a first dielectric material, and the second component (602) is made of a second dielectric material, wherein the dielectric constant of the first is less than that of the second, and the first dielectric material is an inert material, which may be a plastic type material selected from the group consisting of: high-density polyethylene (abbreviated as HDPE), polystyrene (abbreviated as PS), polytetrafluoroethylene (a polymer belonging to the class of perfluorocarbons abbreviated as PFC, known through the trade name Teflon®), and optionally any combination thereof, and the second dielectric material may be selected from the group consisting of: ceramic materials (e.g., aluminum oxide Al2O3, or alumina, barium titanate BaTO3), crystalline materials (e.g., aluminum oxide Al2O3 in mineral form as corundum, or sapphire), and optionally combination thereof.

21. The dielectric structure comprises a first component (601) made of a first dielectric material, a second component (602), and a plurality of further components, each made of a different dielectric material, wherein the second component (602) and the plurality of further components are completely housed within the body (5), as described in any one of claims 1 to 4.

22. The electromagnetic detector according to claim 21, wherein the first component (601) comprises an outer portion (603) that at least partially covers the detection channel (4) and an inner portion (604) that is housed inside the main body (5), and the second component (602) and the plurality of further components are completely housed in the inner portion (604) of the first component (601).

23. The electromagnetic detector (1) according to any one of claims 1 to 4, wherein the dielectric structure comprises the first component (601) and a plurality of other distinct components made of different dielectric materials, the first component (601) and the plurality of other components are arranged to partially cover the detection channel (4).

24. The electromagnetic detector (1) according to claim 3 or 4, wherein the main body (5) defines a cavity, and the two separation elements (604a, 604b) are configured and arranged to divide the cavity into an emission cavity (505) and a receiving cavity (506).

25. An apparatus for detecting one or more characteristics of a product (2) in the tobacco field, wherein the product is a capsule contained in a rod-shaped article (3), the system comprising an electromagnetic detector (1) according to any one of claims 1 to 4, and a transport device having a sheet configured to hold each article (3) to be inspected and to transport the articles (3) successively perpendicular to their respective longitudinal axes, wherein each section of the article (3) containing the product (2) protrudes from the transport device so as to pass through the detection channel (4) so ​​that the electromagnetic detector (1) can detect characteristics of the product (2), and the electromagnetic field of the detection channel (4) has an electric field oriented parallel to the longitudinal axis of the transported product (3).

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