Electromagnetic detector for detecting properties of products of the tobacco industry

Abstract

What is proposed is an electromagnetic detector for detecting one or more properties of a product of the tobacco industry, wherein the product has a longitudinal axis. The electromagnetic detector comprises a body internally provided with a cavity, which is made of a conductive material and has an interruption configured to define a detecting channel which is open on three sides to allow the product to be conveyed through the detector along a conveying direction. The electromagnetic detector also comprises a coupling component, configured to create an electromagnetic field in a detecting zone of the detecting channel and to receive said electromagnetic field disturbed, in use, by the product present in the detecting channel, and a dielectric structure housed in the cavity and made of non-conductive material. The body comprises an outer body and an inner body which, at least partly, delimit the detecting channel, the dielectric structure comprising a dielectric component, which is also configured to at least partly delimit the detecting channel and is interposed, at least in the detecting zone, between the outer body and the inner body.

Description

[0001] DESCRIPTION ELECTROMAGNETIC DETECTOR FOR DETECTING PROPERTIES OF PRODUCTS OF THE TOBACCO INDUSTRY

[0002] This invention relates to an electromagnetic detector for detecting one or more properties of a product of the tobacco industry.

[0003] In particular, this invention is intended for making an electromagnetic detector, the seat of an electromagnetic field, which comprises a detecting channel, which is open on three sides to allow the product to be conveyed through the electromagnetic detector itself along a conveying direction.

[0004] In detail, the product has a longitudinal axis and the conveying direction is transversal to that longitudinal axis.

[0005] The product may be a tobacco industry article, elongate and having the shape of a rod, such as a traditional cigarette or of the heated tobacco type (for example HNB Heat Not Burned or NGP New Generation Product), or a filter; the article may also optionally contain an additional element whose properties may have to be detected.

[0006] In detail, the additional element may be included in an article made of a fibrous material. In this text, the term fibrous material means a material containing fibres which may be selected in the group consisting of: tobacco, cellulose-based material, other materials. In fact, the article for smoking may be, for example, a segment of filter made of cellulose acetate, or a continuous filter, in a machine for making cigarette filters; or a segment containing tobacco, or a rod of tobacco for making cigarettes; or a segment containing sheets of cellulose-based crimped material, in which balls made of tobacco, or carbon are dispersed.

[0007] Alternatively, the product may be a semi-finished product of the tobacco industry, intended to be wrapped, containing tobacco particles.

[0008] For some time now there has been a widespread presence on the market of articles for smoking containing flavouring substances which the consumer can decide whether or not to activate at the moment of use. Those flavouring substances, for example menthol, may be in liquid form (menthol), or solid, or powdered, and are contained in one or more mechanically breakable capsules positioned in the filters in such a way that the consumer can decide, immediately before smoking each cigarette, or subsequently, whether or not to crush the capsule contained in the filter and disperse the contents in the filter itself to flavour it at the moment of use. The additional element may therefore be a capsule present in the filter, which is intended to be crushed at the moment of use.

[0009] It should be added that, at present, it is possible to make very complex cigarettes comprising series of portions of different types and composition. For this reason, generically, the term “cigarette” refers to the generic elongate article for smoking for the tobacco industry comprising an active portion intended to release a substance to be inhaled. The additional element whose one or more properties must be detected could be, in this case, a composite portion, which has a composition different from that of tobacco, or the filter, in which it may be included.

[0010] While those articles of the tobacco industry are being made and packaged, it is therefore important to carry out checks on quality in order to verify that the additional elements contained in them, whether they are capsules or composite portions, comply with quality requirements and meet predetermined acceptability criteria in order to guarantee that the articles for smoking offered to the consumer are always of a predetermined quality.

[0011] In order to carry out those checks, there is increasingly widespread use, as an electromagnetic detector, of a microwave detecting device configured to generate in the detecting channel a microwave detecting electromagnetic field by means of a coupling component. The coupling component is configured to create an electromagnetic field in a detecting zone of the detecting channel and to receive the electromagnetic field disturbed, in use, by the product present in the detecting channel.

[0012] Of particular interest is the possibility of operating the microwave resonator at a low resonance frequency, thereby avoiding dispersing the electromagnetic field outside the detecting channel. However, prior art electromagnetic resonators may be particularly complex to make, in order to be able to guarantee correct detection, or they may be relatively bulky in their extent substantially perpendicular both to the product conveying direction and to the depth of the detecting channel.

[0013] In the case of large microwave resonators, an equally large space must be reserved in the machine for making the articles for smoking, and therefore it is practically impossible to freely select a preferred position for installation of the microwave resonator.

[0014] The aim of this invention is to make an electromagnetic detector for detecting one or more properties of a product of the tobacco industry, which is free of the problems described above and which at the same time is easy and inexpensive to make.

[0015] Another aim of this invention is to make an electromagnetic detector which has small dimensions in such a way that it can easily be installed in any position in a machine for making articles for smoking.

[0016] A further aim of this invention is to make an electromagnetic detector having a detecting channel which is the seat of an electromagnetic field and is open on three sides to allow a product to be conveyed through the electromagnetic detector along a conveying direction, which is capable of checking with a high level of measuring sensitivity the features of the product, whether it is a cigarette, or a filter, or an additional element included in a filter, or in a cigarette, or whether it is a semi-finished product intended to be wrapped.

[0017] These aims and others are all achieved by an electromagnetic detector according to this invention as set out in the independent claims below or in any of the claims directly or indirectly dependent on the independent claims mentioned.

[0018] Further features and advantages of this invention will be more apparent from the approximate, and therefore non-limiting description of a preferred, non-limiting embodiment of an electromagnetic detector, as illustrated in the accompanying drawings in which:

[0019] - Figure 1 is a front perspective view of the electromagnetic detector of this invention which comprises a body, internally provided with a cavity and made of a conductive material, which has an interruption configured to define a detecting channel which is open on three sides; and wherein a dielectric structure, housed in the cavity, has a dielectric component configured to at least partly delimit the detecting channel; and wherein a coupling component, fixed to the body, is configured to create an electromagnetic field in the detecting channel;

[0020] - Figure 2 is a rear perspective view of the electromagnetic detector of Figure 1 , which comprises a heating device, and two temperature sensors, which are all fixed to a rear wall of the body;

[0021] - Figure 3 is a front view of the body of Figure 1 ;

[0022] - Figure 4 shows the dielectric structure of Figure 1 , made of a dielectric material in the solid state which is placed so that it completely fills the cavity of the body;

[0023] - Figure 5 is a front perspective view in cross-section of the electromagnetic detector of Figure 1 , showing a source of emission and a source of reception of the coupling component which are positioned in the dielectric structure and in which the cross-section plane passes through a central plane of symmetry of the body;

[0024] - Figure 6 is a cross-section of the electromagnetic detector of Figure 5, showing the electric field lines present in the detecting zone;

[0025] - Figure 7 is a front perspective view in cross-section of a variant of the electromagnetic detector of Figure 1 , in which the electromagnetic detector comprises a variant of the dielectric structure of Figure 1 and in which the cross-section plane passes through the central plane of symmetry of the body;

[0026] - Figure 8 is a perspective view of another variant of the electromagnetic detector of Figure 1 , in which the electromagnetic detector comprises a version of the body of Figure 1 and a version of the dielectric structure of Figure 1 , in which the body and the dielectric structure define respective regions which project into the detecting channel and are opposite each other, in such a way that a passage section of the detecting zone in the detecting channel between the above-mentioned regions is smaller than a remaining section of the detecting channel;

[0027] - Figure 9 is a cross-section of the electromagnetic detector of Figure 8, showing the projecting regions of the detecting zone and electric field lines present in the detecting zone, which is defined between the projecting regions, and in which the cross-section plane passes through the central plane of symmetry of the body;

[0028] - Figure 10 is a perspective view of the body of Figure 8;

[0029] - Figure 1 1 is a perspective view of the dielectric structure of Figure 8. Hereinafter, the same elements will be referred to using the same numbers in the various figures.

[0030] Figures 1 to 11 show an electromagnetic detector 1 , 1 ’, 1 ” hereinafter indicated more simply as a detector, for detecting one or more properties of a product 2 of the tobacco industry.

[0031] The product 2 may be an elongate rod-shaped article, such as a cigarette, or a filter, and it may optionally contain an additional element 3 whose properties may have to be detected, such as for example a capsule included in a cigarette, as shown in Figures 1 , 5, 6, 7 and 9.

[0032] The product 2 has a longitudinal axis A.

[0033] The additional element 3 may, for example, be the capsule containing a flavouring substance (in liquid form, or solid, or in the form of pressed powder) present in the filter, which is intended to be crushed at the moment of use, but the additional element 3 may also be an active portion of a plurality of composite portions of a cigarette, which has a composition different from that of tobacco, or the filter, in which it may be included.

[0034] In this text the term “property of the product” therefore means, if the product 2 is a rod-shaped article which has an additional element 3, a feature selected in the group consisting of: presence, or absence, of the additional element 3 in the article, correct quantity / correct filling, and possible breakage during production of the article itself, longitudinal positioning in the article, moisture, weight, dimensions, and possibly the material used to make the additional element 3.

[0035] If the product 2 is a semi-finished product intended to be wrapped, the electromagnetic detector 1 can detect the following “properties of the product”: moisture, weight or density of the semi-finished product, for example before it is wrapped with metallized paper (or paper containing metal particles).

[0036] As has already been described in detail, the electromagnetic detector 1 , 1 ’, 1 ” according to this invention may advantageously be used in various machines of the tobacco industry, and even in other automatic machines of other industrial sectors, where one or more properties of a product 2 must be detected.

[0037] Figures 1 to 6 show an electromagnetic detector 1 which comprises a body 4 which is internally hollow, made of a conductive material. Therefore, the body 4 is provided with a cavity 401 which is delimited inside the body 4.

[0038] The body 4 is preferably made of aluminium.

[0039] The body 4 has an interruption configured to define a detecting channel 5 which is open on three sides to allow the product 2 to be conveyed through the electromagnetic detector 1 along a conveying direction D.

[0040] It should be noticed that the conveying direction D, shown in Figure 1 , is transversal to the longitudinal axis A of the product 2.

[0041] The detecting channel 5 extends longitudinally and has a longitudinal axis of extension Y which may be parallel to the conveying direction D.

[0042] In addition, the detector 1 comprises a coupling component, configured to create an electromagnetic field in a detecting zone 501 of the detecting channel 5 and to receive said electromagnetic field disturbed, in use, by the product 2 present in the detecting channel 5.

[0043] In fact, the electromagnetic field is altered by the presence of the product 2 in the detecting channel 5 and that allows detection of one or more properties of the product 2 during said conveying of the product 2.

[0044] That disturbance can be measured and from this measurement, by means of subsequent processing, it is possible to determine the properties of the product 2, and also the properties of any additional element 3 present in the product 2, if the additional element 3 is present.

[0045] If we consider an axis Z, it is perpendicular to that longitudinal axis of extension Y and to the longitudinal axis A of the product 2, when the product is in the detecting zone 501 .

[0046] The electromagnetic detector 1 also comprises a dielectric structure 9, which is housed in the cavity 401 and is made of a non-conductive material. The body 4 comprises an outer body 7 and an inner body 8, which, at least partly, delimit the detecting channel 5.

[0047] The dielectric structure 9, shown in Figure 4, comprises a dielectric component which is also configured to at least partly delimit the detecting channel 5 and is interposed, at least in the detecting zone 501 , between the outer body 7 and the inner body 8.

[0048] Thanks to the fact that the dielectric component is interposed, at least in the detecting zone 501 between the outer body 7 and the inner body 8, it is possible to concentrate the electromagnetic field in the detecting zone 501.

[0049] This makes it possible to have an electromagnetic resonator 1 with a high level of measuring sensitivity, but which is simple to make, in which the dielectric component is placed in the detecting channel 5 so that it closes the cavity 401 , in such a way that the latter is sealed and cannot be contaminated by extraneous particles present in the machines of the tobacco industry.

[0050] For this reason, the dielectric component is made of a dielectric material in the solid state which may be an inert material, accepted amongst those intended for contact with food, for example a material of the plastic type, which may be selected in 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 by its brand name Teflon™); and if necessary any combination of them.

[0051] In fact, it is known that plastic materials do not negatively impact consumer health and do not affect the quality of the products with which they may come into contact and therefore they are particularly used for products intended for consumption.

[0052] It should be noticed that, in detail, in the detecting zone 501 the dielectric component is interposed between the outer body 7 and the inner body 8 at least along an axis parallel to the longitudinal axis A of the product 2, when in use the product 2 is in the detecting zone 501 .

[0053] The detecting channel 5 has a first wall 502 and a second wall 503 which are opposite each other.

[0054] The distance between the first wall 502 and the second wall 503 defines a passage section of the detecting channel 5, which corresponds to a height of the detecting channel 5 along the axis Z.

[0055] In detail, the first wall 502 and the second wall 503 may be planar, as shown in the accompanying Figures 1 to 7, parallel with each other and perpendicular to the axis Z. However, according to an embodiment not illustrated, that is not necessary. In fact, advantageously, the first wall 502 and the second wall 503 may be curved, or slightly inclined relative to each other and transversal to the axis Z, if this shape facilitates the passage of the product 2 in the detecting channel 5.

[0056] The electromagnetic detector 1 is “C”-shaped and if it is installed in the machine of the tobacco industry as illustrated in Figure 1 , the axis Z is the vertical axis.

[0057] A back wall 504, interposed between the first wall 502 and the second wall 503, delimits a back of the detecting channel 5. The back wall 504 may be transversal to the first wall 502 and to the second wall 503, in particular the back wall 504 may be perpendicular to them.

[0058] The dielectric component comprises a first dielectric element 901 positioned in the first wall 502 and a second dielectric element 902 positioned in the second wall 503. The first dielectric element 901 and the second dielectric element 902 are opposite each other and define the detecting zone 501 between them.

[0059] The inner body 8 extends along a respective longitudinal axis K which is parallel to a longitudinal axis A of the product 2 when, in use, the product 2 is in the detecting zone 501 . As shown in Figure 3, the inner body 8 has a lateral wall 804, provided with an end and an end wall 805, which is transversal to that longitudinal axis K and extends from that end.

[0060] If we now consider the interruption caused by the detecting channel 5, it defines in the inner body 8 a first part 801 and a second part 802.

[0061] The first part 801 has a first surface 801 a which at least partly delimits the detecting channel 5, the second part 802 has a second surface 802b which at least partly delimits the detecting channel 5.

[0062] In detail, the first part 801 and the second part 802 of the inner body 8 project from a back part 803.

[0063] The first surface 801 a is positioned on the first wall 502 of the detecting channel 5, whilst the second surface 802b is positioned on the second wall 503 of the detecting channel 5.

[0064] The first surface 801 a and the second surface 802b may be planar, or follow the shape of the first wall 502 and of the second wall 503, if the first wall 502 and the second wall 503 have a different shape and for example are curved.

[0065] It should be noticed that the first dielectric element 901 and the second dielectric element 902 define respectively in the first wall 502 and second wall 503 a first outline and a second outline, wherein the first outline delimits inside it the first surface 801 a of the inner body 8, and wherein the second outline delimits inside it the second surface 802b of the inner body 8. In other words, the first outline and the second outline delimit the perimeter respectively of the first surface 801 a and the second surface The first outline extends for the entire extent of the first wall 502 and the second outline extends for the entire extent of the second wall 503 so that the outer body 7 and the inner body 8 are never in contact.

[0066] Similarly, the interruption of the detecting channel 5 defines in the outer body 7 a first outer portion 701 , on the same side as the first wall 502, and a second outer portion 702, on the same side as the second wall 503, which towards the outside delimit the detecting channel 5 and are delimited, on the inside, respectively by the first outline and by the second outline which are respectively defined by the first dielectric element 901 and by the second dielectric element 902.

[0067] The first outer portion 701 has a first area 701 a, for example planar, which at least partly defines the first wall 502. The second outer portion 702 has a second area 702b, for example planar, which at least partly defines the second wall 503.

[0068] The first area 701 a and the second area 702b may be planar, or follow the shape of the first wall 502 and of the second wall 503, if the first wall 502 and the second wall 503 have a different shape and for example are curved.

[0069] The first outline is externally delimited at the perimeter by the first area 701 a of the first outer portion 701 whilst the second outline is externally delimited at the perimeter by the second area 702b of the second outer portion 702.

[0070] The dielectric structure 9 may be made of the dielectric material in the solid state, which is placed so that it completely fills the cavity 401 of the body 4, as shown in Figure 4.

[0071] It should be noticed that the cavity 401 comprises a first recess 402, which extends along a respective longitudinal axis, which is coaxial with the longitudinal axis K of the inner body 8, has a curved shape and extends as far as the detecting channel 5. In detail, the first recess 402 comprises two curved sections deriving from a cylindrical cavity, each of which extends as far as the detecting channel 5. The cavity 401 also comprises a second recess 403 which extends from one end of the first recess 402 and is transversal to the longitudinal axis K. The second recess 403 also extends as far as the detecting channel 5. The dielectric structure 9, shown in Figure 4, may have a lateral panel 903, which is provided with an end, and an end panel 904, which extends from said end.

[0072] The lateral panel 903 extends along a respective longitudinal axis W, which is parallel to the longitudinal axis A of the product 2 when, in use, the product 2 is in the detecting zone 501 . The end panel 904 is transversal to that longitudinal axis W, in particular it is perpendicular to it.

[0073] The lateral panel 903 is placed so that it completely fills the first recess 402, whilst the end panel 904 is placed so that it completely fills the second recess 403.

[0074] It should be noticed that both the lateral panel 903, and the end panel 904 are interrupted by the detecting channel 5 and that this interruption defines in the lateral panel 903 a niche 903’ and another niche 903” and defines in the end panel 904 a first zone 904a and a second zone 904b.

[0075] The niche 903’ and the other niche 903” are positioned on opposite sides of the lateral panel 903 along the conveying direction D. In other words, they are respectively positioned upstream and downstream of the detecting zone 501 along the conveying direction D.

[0076] The lateral panel 903 also has a first curved portion 903a and a second curved portion 903b, for example deriving from a cylindrical tubular shape of the lateral panel 903, which are adjacent respectively to the first zone 904a and to the second zone 904b.

[0077] The dielectric component, made of the dielectric material in the solid state which at least partly delimits the detecting channel 5, is defined by respective final edges of the lateral panel 903 and of the end panel 904 which are identified by the niche 903’, by the other niche 903”, by the first zone 904a and by the second zone 904b.

[0078] In fact, the first dielectric element 901 of the dielectric component is defined by the final edges of the lateral panel 903 and of the end panel 904 facing the first wall 502.

[0079] It can be seen how the first dielectric element 901 is defined by a final stretch of the first zone 904a, by a pair of lateral final stretches, which are adjacent to that first zone 904a, wherein one lateral final stretch is defined by the niche 903’ whilst the other lateral final stretch is defined by the other niche 903”.

[0080] Similarly, the second dielectric element 902 of the dielectric component is defined by the final edges of the lateral panel 903 and of the end panel 904 facing the second wall 503.

[0081] In detail, the second dielectric element 902 is defined by a respective final stretch of the second zone 904b, and by another pair of lateral final stretches, which are adjacent to that second zone 904b, wherein one final stretch is defined by the niche 903’ whilst the other lateral final stretch is delimited by the other niche 903”.

[0082] It should be noticed that the final stretch of the first zone 904a and the final stretch of the second zone 904b are those directed further outwards in the detecting channel 5, if we consider the longitudinal axis W of the dielectric structure, and are those between which the detecting zone 501 is defined, in the electromagnetic detector 1 , when the dielectric structure 9 is housed in the cavity 401 of the body 4.

[0083] However, the first dielectric element 901 and the second dielectric element 902 are opposite each other in the detecting channel 5, in the entire first wall 502 and in the entire second wall 503.

[0084] The lateral wall 804 of the inner body 8 externally delimits the first part 801 and the second part 802, which are defined by the interruption caused by the detecting channel 5.

[0085] In particular, the first part 801 is externally delimited by means of a first lateral wall 804a of the lateral wall 804, whilst the second part 802 is respectively delimited by means of a second lateral wall 804b. A first end wall 805a of the end wall 805 frontally delimits the first part 801 , whilst a second end wall 805b of the end wall 805 frontally delimits the second part 802.

[0086] The lateral wall 804 of the inner body 8 may have a curved shape, for example deriving from a cylindrical tubular shape, which is interrupted by the detecting channel 5.

[0087] The lateral panel 903 of the dielectric structure 9 is coaxial with the inner body 8 and surrounds the inner body 8, and, that is to say, the respective longitudinal axes W and K of the dielectric structure 9 and of the inner body

[0088] 8 coincide in the electromagnetic detector 1 , when the dielectric structure

[0089] 9 is housed in the cavity 401 .

[0090] Moreover, the lateral wall 804 of the inner body 8 is in contact with the lateral panel 903 of the dielectric structure 9, the end wall 805 of the inner body 8 is in contact with the end panel 904 of the dielectric structure 9.

[0091] In detail, the first end wall 805a is in contact with the first zone 904a, whilst the second end wall 805b is in contact with the second zone 904b.

[0092] As regards the outer body 7, the first outer portion 701 is in contact with the first zone 904a of the end panel 904, whilst the second outer portion 702 is in contact with the second zone 904b of the end panel 904.

[0093] The first outer portion 701 is also in contact with the first curved portion 903a of the lateral panel 903 whilst the second outer portion 702 is also in contact with the second curved portion 903b of the lateral panel 903.

[0094] Now considering the back wall 504 of the detecting channel 5, it can be seen how in the back wall 504 the dielectric component has a back dielectric element 905’ and another back dielectric element 905” which are also interposed between the outer body 7 and the inner body 8.

[0095] They are defined by a respective final stretch of the lateral panel 903, placed on a back of the niche 903’, by another respective final stretch placed on a back of the other niche 903”.

[0096] Along the conveying direction D, the back part 803 of the inner body 8 is interposed, on one side between the back dielectric element 905’ and the outer body 7, whilst on the other side the back part 803 of the inner body 8 is interposed between the other back dielectric element 905” and the outer body 7.

[0097] Thanks to the fact that the outer body 7 substantially surrounds the dielectric structure 9, which in turn surrounds the inner body 8, the interruption defined by the detecting channel 5 defines the first dielectric element 901 and the second dielectric element 902, which in turn define respectively in the first wall 502 and second wall 503 the first outline and the second outline, but the latter are also respectively connected to the back dielectric element 905’ and to the other back dielectric element 905”. Consequently, the dielectric component of the dielectric structure 9 is interposed in the entire detecting channel 5 between the outer body 7 and the inner body 8, although the detecting zone 501 is identified between the first dielectric element 901 and the second dielectric element 902 at the final edges of the first zone 904a and of the second zone 904b, in particular along the longitudinal axis K of the inner body 8.

[0098] Figure 7 shows an electromagnetic detector 1 ’ which is a variant of the electromagnetic detector 1 of Figures 1 to 6 and differs from the latter exclusively because it comprises a dielectric structure 9’ which differs from the dielectric structure 9, comprising a dielectric material in the gaseous state, that is to say, air, which partly fills the first recess 402 of the cavity 401.

[0099] Everything previously said with reference to the electromagnetic detector 1 remains valid, for example relative to the cavity 401 , the outer body 7 and the inner body 8.

[0100] In addition to the dielectric material in the gaseous state, the dielectric structure 9’ comprises a dielectric material in the solid state which has a first closing element (not illustrated) of the first recess 402, positioned in the first wall 502, and a second closing element (not illustrated) of the first recess 402, positioned in the second wall 503, and a further end panel 904’ completely filling the second recess 403.

[0101] The first closing element and the second closing element are such that they prevent extraneous bodies such as tobacco particles from being able to enter the cavity 401 inside the body 4, in such a way that the latter is sealed and cannot be contaminated.

[0102] Differently from the first curved portion 903a and the second curved portion 903b of the lateral panel 903 of the dielectric structure 9, which is placed so that it completely fills the first recess 402, the first closing element and the second closing element of the dielectric structure 9’ may have limited thickness.

[0103] The further end panel 904’ is interrupted by the detecting channel 5, and the latter defines in the further end panel 904’ a further first zone 904a’ and a further second zone 904b’.

[0104] It should be noticed that the dielectric component comprises a first dielectric element 901 ’ defined by a final edge of the further first zone 904a’ and by the first closing element, and a second dielectric element 902’, defined by the respective final edge of the further second zone 904b’ and by the second closing element.

[0105] Similarly to what was previously said, which remains valid, the first dielectric element 90T and the second dielectric element 902’ define respectively in the first wall 502 and second wall 503 the first outline and the second outline, wherein the first outline delimits inside it the first surface 801 a of the inner body 8, and wherein the second outline delimits inside it the second surface 802b of the inner body 8.

[0106] In other words, the first outline and the second outline delimit the perimeter respectively of the first surface 801 a and the second surface 802b.

[0107] It continues to be the case that the final stretch of the further first zone 904a’ and the final stretch of the further second zone 904b’ are those directed further outwards in the detecting channel 5, if we consider the longitudinal axis W of the dielectric structure, and are those between which the detecting zone 501 is defined, in the electromagnetic detector 1 , when the dielectric structure 9’ is housed in the cavity 401 of the body 4.

[0108] The first closing element and the second closing element extend, respectively, from the opposite ends of the further first zone 904a’, considering the ends along the conveying direction D, towards the back wall 504 and from the opposite ends of the further second zone 904b’, considering the ends along the conveying direction D, towards the back wall 504. In other words, both the first closing element and second closing element comprise respective parts positioned upstream and downstream of the detecting zone 501 along the conveying direction D, which project towards the back wall 504 to define the first dielectric element and the second dielectric element, in combination with the final stretch of the further first zone 904a’ and with the final stretch of the further second zone 904b’, respectively in the first wall 502 and in the second wall 503.

[0109] The further end panel 904’, is shaped like an interrupted disk, which is placed in the second recess 403’ in such a way as to prevent extraneous bodies such as tobacco particles from being able to enter the cavity 401 inside the body 4.

[0110] Thanks to the fact that the electromagnetic structure 9’ comprises only the further end panel 904’ made of the dielectric material in the solid state, the first closing element and the second closing element, it is simple to make and guarantees a good level of measuring sensitivity for the product 2. The first recess 402, filled with air, surrounds the inner body 8.

[0111] In fact, the lateral wall 804 of the inner body 8 delimits the first recess 402 whilst the end wall 805 of the inner body 8 is in contact with the further end panel 904’.

[0112] In detail, the first end wall 805a is in contact with the further first zone 904a’, whilst the second end wall 805b is in contact with the further second zone 904b’.

[0113] The first outer portion 701 of the outer body 7 is in contact with the further first zone 904a’ of further end panel 904’, whilst the second outer portion 702 of second wall 503 is in contact with the further second zone 904b’ of the further end panel 904’.

[0114] According to another variant of the electromagnetic detector 1 of Figures 1 to 6 and of Figure 7, not illustrated, the electromagnetic detector comprises a dielectric structure which differs from the dielectric structure 9 and also from the dielectric structure 9’, since it comprises a dielectric material in the gaseous state, that is to say, air, which partly fills the first recess 402 and the second recess 403 of the cavity 401 . In this case, the dielectric structure comprises a dielectric material in the solid state which has a first protective element (not illustrated) for the first recess 402, and for the second recess 403, positioned in the first wall 502, and a second protective element (not illustrated) for the first recess 402 and for the second recess 403, positioned in the second wall 503. The first protective element and the second protective element may have limited thickness since they must only guarantee that the cavity 401 is sealed and cannot be contaminated by any extraneous particles.

[0115] In this case, the dielectric component comprises a first dielectric element defined by the first protective element and a second dielectric element defined by the second protective element, which define respectively in the first wall 502 and second wall 503 the first outline and the second outline. With reference to Figures 8 to 1 1 , they show an electromagnetic detector 1 ” which is another variant of the electromagnetic detector 1 of Figures 1 to 6 and differs from the latter since it comprises a body 4” which is another embodiment of the body 4 of Figure 1 , and a dielectric structure 9” which is another embodiment of the dielectric structure 9. In fact, the interruption defined by the detecting channel 5 defines a first wall 502” and a second wall 503’ which differ from those described above.

[0116] The body 4” and the dielectric structure 9” are such that together they define in the detecting channel 5 a detecting zone 501 ” where a passage section of the detecting channel 5, between the first wall 502” and the second wall 503”, is smaller than the remaining passage sections of the detecting channel 5.

[0117] In detail and as shown in Figure 8, the first wall 502” has a first region 505, which projects relative to the other zones of the first wall 502”, and the second wall 503” has a respective second region 506, which projects relative to the other zones of the second wall 503”, which extend, parallel to the conveying direction D, for the entire extent of the detecting channel 5.

[0118] The first region 505 and the second region 506 are opposite each other and therefore, between the first region 505 and the second region 506 a detecting zone 501 ” is defined in which the passage section of the detecting channel 5 is smaller.

[0119] For example, the first region 505 may project relative to the other zones of the first wall 502” by a height of between 1 / 10 and 1 / 2 of the passage section of the detecting channel 5, that is to say, of the height of the detecting channel 5.

[0120] Similarly, for example, the second region 506 may also project relative to the other zones of the second wall 503” by a height of between 1 / 10 and 1 / 2 of the passage section of the detecting channel 5, that is to say, of the height of the detecting channel 5.

[0121] It should be noticed that the height of the first region 505 may be different from the height of the second region 506, even if, preferably, the height of the first region 505 is equal to the height of the second region 506.

[0122] However, it is not necessary for the first wall 502” and the second wall 503” to have the respective first region 505 and the respective second region 506, since it is sufficient for the respective first region 505 or the respective second region 506 to be present in order to reduce the passage section of the detecting channel 5.

[0123] It should be noticed that, although shown with substantially planar final ends, the first region 505 and the second region 506 may respectively follow the shape of the first wall 502” and of the second wall 503”, that is to say, they may even be curved, or slightly inclined relative to each other, as already indicated.

[0124] In this embodiment of the electromagnetic detector 1 ”, a dielectric structure 9” is present which has the same lateral panel 903 as the dielectric detector 1 , placed so that it completely fills the first recess 402 of the cavity 401 , and an end panel 904”, which differs from the end panel 904 since not only is it placed so that it completely fills the second recess 403 but it also projects from it.

[0125] In this case, whilst the lateral panel 903 is interrupted by the detecting channel 5 for the entire passage section of the detecting channel 5, and the interruption defines in the lateral panel 903 a niche 903’ and another niche 903”, the end panel 904” is interrupted by a smaller passage section, thereby defining a first zone 904a” and a second zone 904b”, which project along the axis Z towards the detecting channel 5 and also project, respectively, relative to the first curved portion 903a and to the second curved portion 903b, defined in the lateral panel 903 by the interruption of the detecting channel 5.

[0126] In this way a first dielectric element 901 ” is defined which differs from the first dielectric element 901 since it is defined by a final edge of the of the first zone 904a”, which projects from the first wall 502”, and by the pair of lateral final stretches, which are adjacent to that first zone 904a”, of the first curved portion 903a, wherein one lateral final stretch is defined by the niche 903’ whilst the other lateral final stretch is defined by the other niche 903”.

[0127] The first region 505 of the first wall 502” comprises a central part which is defined by the final edge of the first zone 904a”.

[0128] A second dielectric element 902” is also similarly defined, which differs from the second dielectric element 902 since it is defined by a final edge of the second zone 904b”, which projects from the second wall 503”, and by the pair of lateral final stretches, which are adjacent to that second zone 904b”, of the second curved portion 903b, wherein one lateral final stretch is defined by the niche 903’ whilst the other lateral final stretch is defined by the other niche 903”.

[0129] The second region 506 of the second wall 503” comprises a central part which is defined by the final edge of the second zone 904b”. The body 4” has the same inner body 8 as the electromagnetic detector 1 but differs from the body 4 of the electromagnetic detector 2 since it has an outer body 7” in which there are defined, by the interruption of the detecting channel 5, a first outer portion 701 ” and a second outer portion 702” wherein the first outer portion 701 ” has a first pair of lateral teeth 703 which project from the first wall 502” and the second outer portion 702” has a second pair of lateral teeth 704 which project from the second wall 503”.

[0130] The two lateral teeth 703 of the first outer portion 701 ” are positioned at the sides of the final edge of the first zone 904a”, to define the lateral parts of the first region 505, and are aligned with the first zone 904a” along the conveying direction D.

[0131] The two lateral teeth 704 of the second outer portion 702” are positioned at the sides of the final edge of the second zone 904b” to define the lateral parts of the second region 506, and are aligned with the second zone 904b” along the conveying direction D.

[0132] However, it should again be emphasised that it is not necessary for the first wall 502” and the second wall 503” to both have a projecting region, since it is sufficient for the projecting region to be present only in one of the two lateral walls 502”, or 503” in order to reduce the passage section of the detecting channel 5. In this case, the other lateral wall 503, or 502, may have the same shape as the embodiment of Figures 1 to 6, without projections.

[0133] In this case too, a passage section of the detecting channel 4 at the projecting region is smaller than the passage section of the detecting channel 4 at the remaining zones.

[0134] It should be noticed that it is at the detecting zone 501 ” between the first wall 502” and the second wall 503”, that the passage section of the detecting channel 5 is smaller than the remaining passage sections of the detecting channel 5.

[0135] In this way, the distance between the product 2 and the electromagnetic detector 1 ” is reduced during the passage of the product 2 in the detecting channel 5. This allows a further increase in the intensity of the electric field in the detecting zone 501 ”, the electric field being parallel to a longitudinal axis A of the product 2, as is indicated in more detail below.

[0136] Increasing the intensity of the electric field consequently increases the measuring sensitivity, movement of the product 2 closer to the electromagnetic detector 1 ” being promoted as much as possible.

[0137] For that reason it should be noticed that, in Figure 9, the arrows indicating the intensity of the electromagnetic field in the detecting zone 501 ” are different from the arrows shown in Figure 6.

[0138] According to one variant not shown, along the conveying direction D the first region 505 and / or the second region 506 may have end edges which are rounded, or inclined, in such a way as to promote the entry, or the exit of the product 2 into / from the detecting channel 5 along the conveying direction D. That is optional and may be advantageous for products 2 such as elongate articles for smoking, such as cigarettes, or filters, one of whose stretches may pass through the detecting channel 5 along the conveying direction D.

[0139] As shown at least in Figures 6 and 9, the coupling component is oriented and fixed to the body 4, or 4”, to create an electromagnetic field having an electric field distribution lying parallel to a longitudinal axis of the inner body 8, which is parallel to a longitudinal axis A of the product 2, when in use the product 2 is in the detecting zone 501 .

[0140] The coupling component comprises at least one source of emission 601 and one source of reception 602, which are oriented and fixed to the body 4, or 4”, in such a way as to both be perpendicular to a longitudinal axis of the inner body 8.

[0141] It should be noticed that in Figures 5, 6, 7 and 9 the source of emission 601 and the source of reception 602 are shown aligned and positioned at 180° from each other, placed at a central plane of symmetry. However, that is not necessary, since it is sufficient for the source of emission 601 and the source of reception 602 to be positioned at least at an angular distance of 90° from each other.

[0142] It should be added that the coupling component is oriented and fixed to the body 4, or 4”, to create an electromagnetic field having an electric field distribution having a maximum intensity in the detecting zone 501 ; 501 ”. Thanks to that, it is possible to detect the properties of the product 2 in an optimum way.

[0143] It should be noticed that the features described above relative to the electric field distribution, the intensity of the electric field and the positioning relative to each other of the source of emission 601 and the source of reception 602 of the coupling component are valid for the electromagnetic detector 1 , and for the electromagnetic detector 1 ’ and 1 ” and are shown in Figures 6 and 9 only for illustrative purposes, since they do not depend on the configuration selected for the dielectric structure 9, or 9’, or 9”.

[0144] According to a variant not shown, if the electromagnetic detector is of the type which uses reflection, the coupling component may comprise a single source of emission and reception. However, the above remains valid with reference to the features relative to electric field distribution and to the intensity of the electric field with reference to the electromagnetic detector 1 , 1 ’, or 1 ”.

[0145] Preferably, the electromagnetic detector 1 ; T, or 1 ” is a microwave resonator, operating at a resonance frequency greater than or equal to 100 MHz and less than or equal to 2 GHz, wherein the electromagnetic field is a microwave electromagnetic field.

[0146] Given the structure of the electromagnetic detector 1 , T, or 1 ” it can be seen how the resonance frequency is, in this case, easily selectable since it changes with changes in the longitudinal extent of the inner body 8, along the longitudinal axis of extension K, that is to say, a depth of the electromagnetic detector 1 , T, or 1 ” which also determines the longitudinal extent of the lateral panel 903, or of the first recess 402 of the cavity 401 . In detail, changing the depth of the electromagnetic detector 1 , T, or 1 ” along the longitudinal axis K, reduces the resonance frequency.

[0147] That allows optimum design of the features of the electromagnetic detector 1 , T, or 1 ” operating as a microwave resonator depending on the installation space in the machine of the tobacco industry.

[0148] At the same time, working at low resonance frequencies, it is possible to obtain a high level of measuring sensitivity for detecting product features, by easily delimiting the electromagnetic field in the detecting zone 501 ; 501 ” of the detecting channel 5.

[0149] It should be noticed that the electromagnetic detector 1 , T, or 1 ” may comprise at least one temperature sensor which is fixed to a rear wall 404 of the body 4, 4” to measure the temperature of the body 4, 4” itself.

[0150] According to a preferred embodiment shown at least in Figure 2, the detector 1 may comprise a pair of temperature sensors 10a, 10b, fixed to the rear wall 404, each positioned to measure the temperature of a first housing defined in the body 4 on the same side as the first wall 502 and of a second housing defined in the body on the same side as the second wall 503.

[0151] The pair of temperature sensor 10a and 10b, perform a temperature measurement capable of correcting the detection of the properties of the product 2 performed, if the electromagnetic field detected is affected by the internal temperature and, therefore, the measurement obtained from the electromagnetic field would also be affected.

[0152] The two temperature sensors 10a and 10b are positioned diametrically opposite each other.

[0153] Advantageously, the electromagnetic detector 1 may comprise a heating device 1 1 fixed to the rear wall 404 for heating the body 4 to a preset operating temperature T.

[0154] The preset operating temperature T may be, for example, a few degrees higher than the maximum temperature which the electromagnetic detector 1 can reach when it is, in use, installed in a machine of the tobacco industry. This maximum temperature reachable may depend on the outside temperature of the factory, in which the machine of the tobacco industry is installed, or may be selected in an appropriate way after a step of training and of detecting the average operating temperature.

[0155] Thanks to the heating device 1 1 a stability in the measurements performed by the electromagnetic detector 1 is guaranteed, therefore avoiding as far as possible correction of the detection of the properties of the product 2 performed, if the electromagnetic field detected is affected by the internal temperature of the electromagnetic detector 1 itself.

[0156] It should be noticed that one of the two temperature sensors 10a, or 10b, may be used to detect the temperature of the electromagnetic detector 1 for the purposes of a feedback check of the heating device 1 1 , whilst the other temperature sensor 10b, or 10a, may be used, in the presence of the two temperature sensors 10a and 10b, for the correction depending on the temperature measured in the detection of the properties of the product 2 performed. In the presence of only the temperature sensor 10a, the latter may be used for the correction of the detection of the properties of the product 2 performed whilst the feedback check of the heating device 1 1 may be delegated to a temperature sensor optionally integrated in the heating device 1 1 itself.

[0157] It should be noticed that what is shown in Figure 2 and described in detail above with reference to the detector 1 , the temperature sensors 10a, or 10b and the heating device 1 1 , also applies to the electromagnetic detector T, or 1 ”.

[0158] There may be an apparatus, not shown, for detecting one or more properties of the product 2. The apparatus may comprise the electromagnetic detector 1 , T, or 1 ” as previously described, and a conveying device, not illustrated, provided with seats configured to retain respective products 2 to be inspected and to convey the products 2 one after another along the conveying direction D.

[0159] If each product 2 comprises the respective additional element 3 to be inspected, a stretch of each product 2 containing the additional element 3 projects relative to the conveying device so that it passes through the detecting channel 5 in such a way that the electromagnetic detector 1 , 1 ’, or 1 ” can detect its properties.

[0160] As already indicated, the products 2 are conveyed perpendicularly relative to their longitudinal axis A along the conveying direction D and when the additional element passes through the detecting zone 501 , or 501 ” the intensity of the electric field is at its maximum in the detecting zone and the electric field is oriented parallel to the longitudinal axis of the product 2. Thanks to the electromagnetic detector 1 , T, or 1 ” described above, in which the body 4, 4” comprises an outer body 7, 7” and an inner body 8 and in which the dielectric structure 9, or 9’, or 9” comprises a dielectric component interposed, at least in the detecting zone 501 , 501 ” between the outer body 7, 7” and the inner body 8, a concentrated electromagnetic field can be generated in the detecting channel 5. If the electromagnetic detector 1 , T, or 1 ” is a microwave detector, it is possible to increase its merit factor and consequently the level of measuring sensitivity, for detecting the features of the product 2, although at a low resonance frequency in the range from 100MHz to 2 GHz.

[0161] Therefore, it is possible to obtain an electromagnetic detector 1 , 1 ’, or 1 ” with compact dimensions at a predetermined resonance frequency, which can easily be installed without problems caused by bulkiness in the machines of the tobacco industry.

Claims

CLAIMS1. Electromagnetic detector (1 ; 1 ’; 1 ”) for detecting one or more properties of a product (2) of the tobacco industry, wherein the product has a longitudinal axis (A), wherein the electromagnetic detector (1 ; 1 ’; 1 ”) comprises:- a body (4; 4”) internally provided with a cavity (401 ), which is made of a conductive material and has an interruption configured to define a detecting channel (5) which is open on three sides to allow the product (2) to be conveyed through the electromagnetic detector (1 ; 1 ’; 1 ”) along a conveying direction (D);- a coupling component (601 ; 602), configured to create an electromagnetic field in a detecting zone (501 ; 501 ”) of the detecting channel (5) and to receive said electromagnetic field disturbed, in use, by the product (2) present in the detecting channel (5);- a dielectric structure (9; 9’; 9”) housed in the cavity (401 ) and made of non- conductive material; and wherein- the body comprises an outer body (7; 7”) and an inner body (8), which, at least partly, delimit the detecting channel (5); and wherein- the dielectric structure (9; 9’; 9”) comprises a dielectric component (901 , 902; 901 ’, 902’; 901 ”; 902”), which is also configured to at least partly delimit the detecting channel (5) and is interposed, at least in the detecting zone (501 ; 501 ”), between the outer body (7; 7”) and the inner body (8).

2. Electromagnetic detector (1 ; 1 ’; 1 ”) according to claim 1 , wherein the detecting channel (5) has a first wall (502; 502”) and a second wall (503; 503”) which are opposite each other; and wherein the dielectric component (901 , 902; 901 ’, 902’; 901 ”; 902”) comprises a first dielectric element (901 ; 901 ’; 901 ”) positioned in the first wall (502; 502”) and a second dielectric element (902; 902’; 902”) positioned in the second wall (503; 503”); and wherein the first dielectric element (901 ; 901 ’; 901 ”) and the second dielectric element (902; 902’; 902”) are opposite each other, the detecting zone (501 ; 501 ”) being defined between the first dielectric element (901 ;901 901 ”) and the second dielectric element (902; 902’; 902”).

3. Electromagnetic detector (1 ; 1 ’; 1 ”) according to one of the preceding claims, wherein the inner body (8) extends along a respective longitudinal axis (K) which is parallel to the longitudinal axis (A) of the product (2) when, in use, the product (2) is in the detecting zone (501 ; 501 ”), and has a lateral wall (804) provided with an end and an end wall (805), which is transversal to that longitudinal axis (K) and extends from that end.

4. Electromagnetic detector (1 ; 1 ’; 1 ”) according to one of the preceding claims, wherein said interruption of the detecting channel (5) defines in the inner body (8) a first part (801 ) and a second part (802) which project from a back part (803); wherein the first part (801 ) has a first surface (801 a) which at least partly delimits the detecting channel (5) and wherein the second part (802) has a second surface (802b) which at least partly delimits the detecting channel (5).

5. Electromagnetic detector (1 ; 1 ’; 1 ”) according to claim 4, when it is dependent on claim 2, wherein the first dielectric element (901 ; 901 ’; 901 ”) and the second dielectric element (902; 902’; 902”) define in the respective first wall (502; 502”) and second wall (503; 503”) a first outline and a second outline, and wherein the first outline delimits inside it the first surface (801 a), which is positioned on the first wall (502; 502”), and the second outline delimits inside it the second surface (802b), which is positioned on the second wall (503; 503”).

6. Electromagnetic detector (1 ; 1 ’; 1 ”) according to claim 5, wherein said interruption of the detecting channel (5) defines in the outer body (7; 7”) a first outer portion (701 ; 701 ”), on the same side as the first wall (502; 502”), and a second outer portion (702; 702”), on the same side as the second wall (503; 503”), which towards the outside delimit the detecting channel (5) and are delimited, on the inside, respectively by the first outline and by the second outline.

7. Electromagnetic detector (1 ; 1 ”) according to one of the preceding claims, when it is dependent on claim 3, wherein the cavity (401 ) comprises a firstrecess (402), which extends along a longitudinal axis coaxial with the longitudinal axis (K) of the inner body (8) and which is provided with an end, and a second recess (403), which extends from said end; wherein the second recess (403) is transversal to that longitudinal axis (K); wherein the dielectric structure (9; 9”) is made of a first dielectric material in the solid state, placed so that it completely fills the cavity (401 ) of the body (4; 4”), which has a lateral panel (903) which is provided with an end, and an end panel (904; 904”), which extends from said end; wherein the lateral panel (903) extends along a respective longitudinal axis (W), which is parallel to the longitudinal axis (A) of the product (2) when, in use, the product (2) is in the detecting zone (501 ), and wherein the end panel (904; 904”) is transversal to that longitudinal axis (W); the lateral panel (903) and the end panel (904; 904”) being interrupted by the detecting channel (5).

8. Electromagnetic detector (1 ; 1 ”) according to claim 7, wherein the lateral panel (903) is coaxial with the inner body (8) and surrounds the inner body (8), the lateral wall (804) of the inner body (8) being in contact with the lateral panel (903) of the dielectric structure (9; 9”), the end wall (805) of the inner body (8) being in contact with the end panel (904; 904”) of the dielectric structure (9; 9’).

9. Electromagnetic detector (1 ; 1 ’) according to claim 7, or 8, wherein said interruption defines in the end panel (904; 904”) a first zone (904a; 904a”) and a second zone (904b; 904b”) and also defines in the lateral panel (903) a niche (903’) and another niche (903”); and wherein the dielectric component (901 ; 902; 901 ”; 902”) is defined by respective final edges of the lateral panel (903) and of the end panel (904; 904”) which are identified by the niche (903’), by the other niche (903”), by the first zone (904a; 904a”) and by the second zone (904b; 904b”).

10. Electromagnetic detector (1 ; 1 ”) according to claim 9, when it is also dependent on claim 6, wherein the first outer portion (701 ; 701 ”) of the outer body (7) is in contact with the first zone (904a; 904a”) of the end panel (904; 904”) and the second outer portion (702; 702”) of the outer body (7; 7”) isin contact with the second zone (904b; 904b”) of the end panel (904; 904”).11 . Electromagnetic detector (1 ”) according to one of the preceding claims, when they are dependent on claim 2, wherein the first wall (502”) has a first region (505), which projects relative to the other zones of the first wall (502”), and / or wherein the second wall (503”) has a second region (506), which projects relative to the other zones of the second wall (503”), the first region (505) and the second region (506) extending parallel to the conveying direction (D) for the entire extent of the detecting channel (5) and being opposite each other in such a way as to define a detecting zone (501 ”) where a passage section of the detecting channel (5), between the first region (505) and the second region (506), is smaller than the passage section of the remaining zones.

12. Electromagnetic detector (1 ”’) according to claim 11 , when it is dependent on claim 10, wherein the dielectric structure (9”) comprises an end panel (904”), which is placed so that it completely fills the second recess (403) and projects from it, and wherein the first zone (904a”) projects from respective final edges of a first curved portion (903a) defined in the lateral panel (903) by the interruption of the detecting channel (5), and wherein the second zone (904b”) projects from respective final edges of a second curved portion (903b) defined in the lateral panel by said interruption; wherein the final edge of the first zone (904a”) defines a central part of the first region (505) and the final edge of the second zone (904b”) defines a central part of the second region (506); and wherein the first outer portion (701 ”) has a first pair of lateral teeth (703) which project from the first wall (502”) and are positioned at the sides of the final edge of the first zone (904a”) to define the lateral parts of the first region (505), and wherein the second outer portion (702”) comprises a second pair of lateral teeth (704) which project from the second wall (503”) and are positioned at the sides of the final edge of the second zone (904b”) to define the lateral parts of the second region (506).

13. Electromagnetic detector (1 ’) according to one of claims from 1 to 6,when it is dependent on claim 3 and on claim 2, wherein the cavity (401 ) comprises a first recess (402), which extends along a longitudinal axis coaxial with the longitudinal axis (K) of the inner body (8) and which is provided with an end, and a second recess (403), which extends from said end; wherein the second recess (403) is transversal to that longitudinal axis (K); and wherein the dielectric structure (9’) comprises a dielectric material in the gaseous state, that is to say, air, partly filling the first recess (402) and a dielectric material in the solid state which has a further end panel (904’) completely filling the second recess (403), a first closing element of the first recess (402) positioned in the first wall (502) and a second closing element of the first recess (402) positioned in the second wall (503); and wherein the further end panel (904’) is interrupted by the detecting channel (5), the latter defining in the further end panel (904’) a further first zone (904a’) and a further second zone (904b’); and wherein the dielectric component (901 ’; 902’) is defined by respective final edges of the further first zone (904a’) and of the further second zone (904b’), by the first closing element and by the second closing element.

14. Electromagnetic detector (1 ’) according to claim 13, wherein the lateral wall (804) of the inner body (8) delimits the first recess (402), the end wall (805) of the inner body (8) being in contact with the further end panel (904’).

15. Electromagnetic detector (1 ; 1 ’) according to one of the preceding claims, wherein the coupling component (601 ; 602) is oriented and fixed to the body (4) to create an electromagnetic field having an electric field distribution lying parallel to a longitudinal axis (K) of the inner body (8), which is parallel to the longitudinal axis (A) of the product (2), when in use the product (2) is in the detecting zone (501 ).

16. Electromagnetic detector (1 ; 1 ’; 1 ”) according to one of the preceding claims, wherein the coupling component (601 ; 602) is oriented and fixed to the body (4) to create an electromagnetic field having an electric field distribution having a maximum intensity in the detecting zone (501 ; 501 ”).

17. Electromagnetic detector (1 ; 1 ’; 1 ”) according to one of the precedingclaims, wherein the coupling component (601 ; 602) comprises at least one source of emission (601 ) and one source of reception (602), which are positioned and fixed to the body (4) in such a way as to both be perpendicular to a longitudinal axis (K) of the inner body (8) and at least positioned at 90° to each other.

18. Electromagnetic detector (1 ; 1 1 ”) according to one of the preceding claims, wherein the electromagnetic detector (1 ; 1 ’; 1 ”) is a microwave resonator operating at a frequency greater than or equal to 100 MHz and less than or equal to 2 GHz and wherein the electromagnetic field is a microwave electromagnetic field.

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