Inspection equipment for quality control of rod-shaped items

Abstract

The present invention relates to an inspection apparatus for quality control of rod-shaped articles, the apparatus comprising: a drum (4) defining an outer surface (13, 40) and including a plurality of seats (41), each seat (41) of the plurality adapted to receive a rod-shaped article; and an inductive sensor (5) located in one of the seats (41), the inductive sensor (5) including a coil (51) defining an interior volume (50) large enough to receive an end of the rod-shaped article therein, the inductive sensor (5) adapted to sense a characteristic of a susceptor (12) within the rod-shaped article, the coil (51) including a first half-coil and a second half-coil; The first half-coil and / or the second half-coil are movable from a first operating position, in which the first half-coil and the second half-coil are in contact with each other to form a coil (51) through which an electric current can flow, to a second operating position, in which the first half-coil and the second half-coil are separated from each other and through which no electric current can flow, and vice versa, wherein the first half-coil is located below the outer surface (13, 40) of the drum (4) and the second half-coil is located above the outer surface (13, 40) of the drum (4), and an actuator (6) adapted to move the first half-coil and the second half-coil from the first operating position to the second operating position and vice versa.

Description

[Technical Field]

[0001] The present invention relates to an inspection device for the quality control of rod-shaped articles, and in particular to an aerosol-generating article in which a conductive band that can be inductively heated is inserted inside the aerosol-generating material, such as a tobacco segment susceptor. [Background technology]

[0002] Aerosol-generating devices are known, and include an aerosol-forming substrate and an induction heating device. The induction heating device includes an induction source that generates an alternating electromagnetic field that induces eddy currents and hysteresis losses that generate heat within a susceptor. The susceptor is in thermal proximity to the aerosol-forming substrate, such as a tobacco substrate. The heated susceptor then heats the aerosol-forming substrate, which includes a material capable of releasing volatile compounds capable of forming an aerosol.

[0003] In some components, the susceptor is positioned inside the aerosol-generating article component.

[0004] Due to manufacturing tolerances, it may occur that the susceptor within a component is not in the desired position or does not have the proper orientation. If the susceptor is left in an incorrect position or orientation, it may result in a lack of product compatibility with respect to aerosol delivery when the component is used in an aerosol generating device. Summary of the Invention [Problem to be solved by the invention]

[0005] It is therefore desirable to detect such defects as early as possible to ensure that only conforming products are manufactured and that unnecessary cost and waste are avoided.

[0006] Furthermore, components (including components that include susceptors) are processed at high speeds (e.g., 5000 components per minute, etc.). Therefore, the time window in which such components can be checked to determine compliance with manufacturing requirements is relatively short. For example, when a component is positioned in the combiner drum, it has a high rotational speed, and the time window for sensors to capture the necessary data to evaluate the shape, position, or presence or absence of a susceptor is approximately 200 milliseconds.

[0007] Therefore, it is desirable to detect susceptor-related defects relatively quickly. DETAILED DESCRIPTION OF THE INVENTION

[0008] In a first aspect, the present invention relates to an inspection apparatus for quality control of rod-shaped articles, comprising a drum defining an outer surface and including a plurality of seats, each seat of the plurality adapted to receive a rod-shaped article. The inspection apparatus preferably includes an inductive sensor positioned in one of the seats, the inductive sensor including a coil defining an internal volume large enough to receive an end of the rod-shaped article therein, the inductive sensor adapted to sense a characteristic of a susceptor within the rod-shaped article. The coil preferably includes a first half-coil and a second half-coil, the first half-coil and the second half-coil being movable from a first operating position in which the first half-coil and the second half-coil contact each other to form a coil through which an electric current can flow to a second operating position in which the first half-coil and the second half-coil are separated from each other, and vice versa.

[0009] According to another aspect of the present invention, there is provided a rod-shaped article. The rod-shaped article may be used, for example, as a component of an aerosol-generating article. The component preferably has a rod shape. The rod-shaped article preferably defines a longitudinal axis. The rod-shaped article preferably defines a first end and a second end.

[0010] The cross section of the rod-shaped article along a plane perpendicular to the longitudinal axis is preferably circular or elliptical. However, the rod-shaped article may also have a rectangular or polygonal cross section. The rod-shaped article preferably has a substantially cylindrical outer surface extending along the longitudinal axis. In the case of a substantially cylindrical rod-shaped article, the longitudinal axis corresponds to the axis of the cylinder.

[0011] The rod-shaped article preferably comprises an aerosol-generating article, or a component of an aerosol-generating article, or two or more components of an aerosol-generating article. The component of the aerosol-generating article may comprise an aerosol-forming substrate. The aerosol-forming substrate may comprise a homogenized tobacco material.

[0012] The rod-shaped article further comprises a susceptor. The susceptor is preferably in thermal contact with the aerosol-forming substrate. The thermal contact is made in order to heat the aerosol-forming substrate. Upon heating, the aerosol-forming substrate emits an aerosol. The susceptor is preferably surrounded by the aerosol-forming substrate. The susceptor is preferably completely inserted within the rod-shaped article component, i.e., the susceptor is not visible from the outside of the rod-shaped article. The susceptor is preferably surrounded in all directions by the aerosol-forming substrate.

[0013] Preferably, the susceptor defines a longitudinal axis. Preferably, the susceptor is closer to the first end of the rod-shaped article than to the second end of the rod-shaped article. If a plane perpendicular to the longitudinal axis is imagined and the rod-shaped article is divided into a first half including the first end and a second half including the second end, the susceptor is preferably located primarily within the first half. Preferably, the susceptor is located at or near the first end of the rod-shaped article. Preferably, the susceptor is fully inserted within the rod-shaped article component. Preferably, the susceptor extends from the first end to the second end of the rod-shaped article component. Preferably, the susceptor defines a longitudinal axis. Preferably, the susceptor is inserted within the rod-shaped article such that its longitudinal axis is parallel to the longitudinal axis of the rod-shaped article. Preferably, the longitudinal axis of the susceptor is parallel to the longitudinal axis of the rod-shaped article or forms an angle of less than 20 degrees with the longitudinal axis of the rod-shaped article. More preferably, the longitudinal axis of the susceptor and the longitudinal axis of the rod-shaped article coincide.

[0014] The longitudinal axis of the susceptor may be the axis of symmetry of the susceptor.

[0015] The susceptor is made of an electrically conductive material. Preferably, the susceptor is made of a metal. Preferably, the susceptor is made of a ferromagnetic material. Although the susceptor is made of an electrically conductive material, it may be covered by another material, a solid (such as a layer of a different material), or a liquid (such as a gel).

[0016] The susceptor preferably has a strip shape, a thickness of 30 micrometers to 60 micrometers, and a length of 5 millimeters to 20 millimeters.

[0017] The rod-shaped article is preferably wrapped in a wrapping sheet.

[0018] The present invention further includes providing a drum. The drum defines a drum rotation axis to which the drum is adapted to rotate around. The drum can be mechanically driven, for example, by a drum drive including gears or a toothed belt. The drum may be driven by an electric drum drive. The drum is preferably cylindrical and has an outer surface. The outer surface is, for example, a substantially cylindrical surface having the drum rotation axis as its geometric center.

[0019] The drum is adapted to convey and rotate rod-shaped articles. Preferably, the drum is adapted to convey and rotate a plurality of rod-shaped articles. Preferably, the drum is adapted to convey and rotate N rod-shaped articles, where 5 < N < 100, more preferably 20 < N < 50. In some embodiments, the drum comprises 40 seats.

[0020] The drum includes at least seats. Preferably, the seats are formed on the outer surface of the drum. Preferably, the drum is adapted to hold rod-shaped articles during conveyance within the seats. For example, the drum is adapted to hold rod-shaped articles within the seats during rotation of the drum about its rotation axis. Preferably, the seats extend in the longitudinal direction along a seat axis. The seats are adapted to receive rod-shaped articles as the drum rotates. Preferably, the rod-shaped articles fit within the seats with their longitudinal axis parallel to the seat axis. Each seat is preferably configured to be able to accommodate a rod-shaped article therein when the seat axis and the longitudinal axis of the rod-shaped article are parallel. More preferably, the seat axis and the longitudinal axis of the rod-shaped article coincide.Preferably, the seats are adapted to accommodate a single rod-shaped article.

[0021] The seat axes are preferably parallel to the drum's axis of rotation, so that when a rod-shaped article is positioned within a seat, the longitudinal axis of the rod-shaped article is preferably parallel to the drum's axis of rotation. All seats are preferably formed on the peripheral surface of the drum. More preferably, the seats are evenly spaced around the drum's outer surface.

[0022] Preferably, all seats present in the drum have the same geometric shape. For example, each seat has a receiving surface adapted to contact the outer surface of the rod-shaped article. Preferably, the receiving surface comprises a concave surface, for example, a portion of a cylindrical surface. The receiving surface is a portion of the outer surface of the drum. The receiving surface may be a portion of a cylindrical surface having a diameter equal to or slightly larger than the diameter of the rod-shaped article transported by the drum. The axis of the receiving surface defines the seat axis.

[0023] The seat axis is preferably parallel to the drum's axis of rotation, so that when the rod-shaped articles are positioned within the drum seat, their longitudinal axes are parallel to the drum's axis of rotation.

[0024] The drum also preferably has a first side and a second side located on two opposite sides of the outer surface. The seat preferably extends from the first side to the opposite second side. The seat may reach the first side, the second side, or both, such that the seat is "open" at two ends. Alternatively, the seat ends do not reach the first side or the second side, in which case the seat is a "closed" seat.

[0025] Each seat preferably includes a suction opening connected to a suction or pneumatic system adapted to hold the rod-shaped articles in the seat by suction while the drum rotates. For example, there may be more than one opening depending on the size and weight of the rod-shaped articles.

[0026] At least one drum seat is associated with an inductive sensor. More preferably, multiple drum seats, and even more preferably, all drum seats, are associated with an inductive sensor. In the technical field, the terms "inductive sensor" and "induction sensor" are synonymous. An inductive sensor uses a current induced by a magnetic field to detect nearby conductive objects, such as metal objects. An inductive sensor includes a coil, which is an inductor, to generate a magnetic field, such as a high-frequency magnetic field. When a conductive object, such as a susceptor embedded in a rod-shaped article, is near a changing magnetic field, current will flow within the conductive object. This resulting current flow within the conductive object creates a new magnetic field that opposes the original magnetic field created by the current flowing in the coil. The net effect is to change the impedance, e.g., resistance, of the "coil and susceptor" system within the inductive sensor. By measuring the impedance, or a parameter function of the impedance, the sensor can determine when a conductive material is brought near the inductive sensor. The change in impedance depends on the type of conductive material from which the object is made, the distance between the object and the sensor, and the size and shape of the object.

[0027] The inductive sensor may be, for example, a Texas Instruments integrated circuit LCD 1101. The inductive sensor preferably measures the equivalent resistance of the susceptor. The inductive sensor may measure the impedance and resonant frequency of the equivalent system (coil and susceptor) by adjusting the amplitude of oscillation in a closed-loop configuration at a constant level while monitoring the energy dissipated by the resonator. By monitoring the amount of power injected into the resonator, the inductive sensor can determine the equivalent parallel resistance of the resonator and return it as a digital value.

[0028] Thus, an inductive sensor is associated with a seat on the drum, and preferably multiple inductive sensors are associated with multiple seats on the drum, one sensor per drum, to detect characteristics of the susceptor embedded within the rod-shaped article.

[0029] The susceptor characteristic may be the presence or absence of a susceptor. The susceptor characteristic may be the length of the susceptor. The susceptor characteristic may indicate the nature or consistency of the shape or composition of the susceptor. Two or more susceptor characteristics may be detected by an inductive sensor. The characteristic may also include the dimensions of the susceptor, the mass of the material from which the susceptor is formed.

[0030] The susceptor property being measured is preferably measured by measuring the impedance of the coil or a parametric function of the system "coil and susceptor".

[0031] The parameter function of the impedance is preferably the impedance Z of the coil itself, or the equivalent resistance of the coil, or the inductance of the coil.

[0032] The inductive sensor includes a coil defining an internal volume. The internal volume is bounded by the windings of the coil. For example, the inductive sensor includes a cylindrical coil with multiple windings of wire. The coil preferably does not include a core, i.e., the internal volume contains air. The internal volume of the coil is preferably large enough to allow at least a portion of a rod-shaped article to be inserted inside the coil. The overall length of the coil is preferably greater than the length of the susceptor. The susceptor length refers to the nominal length of the susceptor when measuring the length of the susceptor is desired. For proper insertion, the inner diameter of the coil is preferably greater than the diameter of the rod-shaped article. The coil preferably defines a longitudinal axis, hereinafter referred to as the coil axis.

[0033] Preferably, the rod-shaped article is inserted into the coil of the inductive sensor. The insertion can be complete, i.e., the entire rod-shaped article is contained within the internal volume of the coil, or only partially, i.e., only a portion of the rod-shaped article is contained within the internal volume of the coil. However, the rod-shaped article is preferably inserted into the coil so that at the end of the insertion, the entire susceptor is located within the internal volume of the coil.

[0034] The coil of the inductive sensor is preferably mounted in the drum seat in such a way that the coil axis and the seat axis are parallel to one another, which preferably results in the coil axis and the longitudinal axis of the rod-shaped article being parallel as well when present in the seat.

[0035] The inductive sensor is used to measure the properties of the susceptor in the rod-shaped article. For this reason, the inspection device preferably includes a control unit. The control unit is preferably electrically connected to the inductive sensor. The control unit generates a signal from the inductive sensor to evaluate the properties of the susceptor. The control unit may be part of the inductive sensor.

[0036] Relative movement between the rod-shaped article and the inductive sensor is effected to insert the rod-shaped article into the inductive sensor.

[0037] Insertion of the rod-shaped article into the coil is preferably performed from a first end of the rod-shaped article. The susceptor is preferably closer to the first end than to the second end, and therefore, the coil required for insertion from the first end is shorter than for insertion from the second end, in order to ensure that the susceptor is fully inserted within the internal volume of the coil. In this way, only a limited portion of the rod-shaped article needs to be inserted into the coil to investigate the properties of the susceptor.

[0038] The coil includes a first half coil and a second half coil. The first half coil and the second half coil are two portions of the coil divided along a plane parallel to the longitudinal axis of the coil. Thus, the first half coil and the second half coil may have different sizes. More preferably, the first half coil and the second half coil are each half of a coil when divided along a plane containing the longitudinal axis of the coil. Each half coil includes multiple half windings. Each half winding is, for example, a circumferential arc, more preferably half a circumference. The circumferential arc of the first half coil and the corresponding circumferential arc of the second half coil form a winding of the coil. The first half coil and the second half coil are movable relative to each other. The movement performed by the first half coil, the second half coil, or both is preferably translational, i.e., linear, movement. The first and second half coils may be in a first operating position in which they are in contact with each other to form a complete coil and allow current to flow through the windings of the coils. In this first operating position, each half winding of the first half coil corresponds to a half winding of the second coil. Furthermore, each half winding of the second half coil corresponds to a half winding of the first half coil. In this first operating position, the contact between the first and second half coils is such that current can flow through the coil formed by the two half coils. Thus, the inductive sensor can detect the characteristics of the susceptor. The conductive strip may be formed, for example, on the outer surface of the drum over which the second or first half coil slides.

[0039] The first and second half coils may be in a second operating state in which the first and second half coils are at a predetermined distance from each other. In this second operating position, not all windings are complete, or there are no complete windings. A "distance" exists between the first and second half coils. The existence of a distance between the first and second half coils means that at least one half winding of the first half coil does not correspond to a half winding of the second half coil. In the second operating position, the two half coils are preferably arranged alternately along the longitudinal axis of the coil, with a gap between them. If some half windings of the first half coil are in contact with some half windings of the second half coil in the second operating position, current may flow through the few full windings formed, but no measurement is performed in this configuration. Alternatively, no current can flow through the coil in the second operating position. The current flow depends on the type of electrical contact between the first and second half coils.

[0040] The first half-coil and the second half-coil are movable from a first operating position to a second operating position, and vice versa.

[0041] When it says "the first half-coil and the second half-coil are movable from a first operating position to a second operating position," it means that only the first half-coil may move, only the second half-coil may move, or both the first half-coil and the second half-coil may move.

[0042] The movement of the first and second half coils may be as follows: The first half coil may move linearly relative to the second half coil; The second half coil is integral with the outer surface of the drum, i.e., the second half coil rotates with the outer surface but does not move relative to it (i.e., the second half coil is stationary relative to it); Alternatively, the second half coil may move linearly relative to the first half coil; The first half coil is stationary relative to the outer surface of the drum, i.e., the first half coil rotates with the outer surface but does not move relative to it; Alternatively, both the first and second half coils move relative to each other; Each of the first and second half coils may reciprocate toward and away from the other of the first and second half coils.

[0043] The first half-coil is positioned below the outer surface of the drum. The term "below surface" means that the first half-coil extends radially inward within the drum. An end of a half-winding of the first half-coil protrudes from the outer surface of the drum so that an electrical connection can be made with the half-winding of the second half-coil to form an electrical connection with the second half-coil. Preferably, the end of the half-winding of the first half-coil is substantially flush with the outer surface of the drum.

[0044] The second half-coil preferably extends over the outer surface of the drum. For example, the drum may include rails, e.g., a pair of rails for each seat along which the second half-coil may run toward and away from the first half-coil.

[0045] The outer surface of the drum may also include a conductive strip that allows the second half-coil to slide toward and away from the first half-coil while ensuring electrical connection between the two half-coils.

[0046] The outer surface may include an electrical track along which the first half-coil moves, so that when the relative positions of the first and second half-coils are such that a complete coil is formed (the first and second half-coils are in the first operating position), the ends of the half-windings of the first half-coil correspond to the ends of the half-windings of the second half-coil, and the conductive track therebetween allows current to flow within the windings so formed.

[0047] The first half coil, the second half coil, or both are moved by an actuator. The actuator may be a linear actuator. The movement is preferably linear in a direction parallel to the coil axis. The movement is preferably linear in a direction parallel to the seat axis. The actuator may include, for example, a pneumatic actuator including a piston. The piston is fixed to the second half coil and moves the second half coil toward and away from the first half coil. The actuator may include a rack and pinion mechanism.

[0048] During operation, the rod-shaped article is positioned in the drum seat, where detection of the susceptor characteristics is performed by an inductive sensor. The inductive sensor may measure a parameter function of the impedance of the coil. The inductive sensor measurements are preferably repeated, i.e., several measurements of the susceptor characteristics are performed during the insertion of the rod-shaped article into the coil. Preferably, several measurements are also performed when the rod-shaped article is extracted from the coil. The positioning of the rod-shaped article in the seat may be due to, for example, transfer from another drum or conveyor. Preferably, at the moment of movement of the rod-shaped article into the seat, the first and second half coils are in the second operating position, thereby allowing positioning of the rod-shaped article in the seat. For example, the positioning is performed so that the rod-shaped article is at least partially positioned above the first half coil.

[0049] When the rod-shaped article is seated in the seat, the first half-coil and the second half-coil are moved by the actuator to a first operating position, thereby forming a coil. When the first half-coil and the second half-coil are moved to the first operating position, the second half-coil slides over the rod-shaped article and encloses a portion of the rod-shaped article.

[0050] A current is generated in the coil and flows along the entire length of the coil, allowing detection of the susceptor's characteristics. The detection made by the inductive sensor can be related to the presence or absence of a susceptor. If a susceptor is not present, no eddy currents are created and there is no change in the magnetic field generated by the coil. Furthermore, the measurement made by the inductive sensor can be related to the size of the susceptor. The signal output by the inductive sensor depends on the material, size, shape, and distance of the susceptor. The material is known, the distance can be measured, and the size or shape of the susceptor can be measured. By knowing the size, such as by knowing the weight, the dimensions of the susceptor can be obtained, for example, from the minimum or maximum signal relative to the impedance of the system "coil and susceptor" measured by the inductive sensor. In fact, the impedance of the "coil and susceptor" also depends on the susceptor's characteristics.

[0051] Therefore, once positioned on the drum seat, no movement of the rod-shaped article is required to obtain the susceptor characteristics. Measurements can be very fast due to the rapid measurements possible with the inductive sensor. No complex mechanical parts are required to move the rod-shaped article. The rod-shaped article avoids deformation due to improper handling within the drum.

[0052] The inspection apparatus preferably includes a control unit, preferably in communication with the inductive sensor, preferably adapted to generate one or more signals in response to a property of the susceptor that are transmitted to the control unit.

[0053] Preferably, the inspection device includes a control unit adapted to command the actuator to move the first half coil, the second half coil, or both, from the second operating position to the first operating position when the rod-shaped article is on the seat. To place the rod-shaped article in the drum seat, the seat is preferably "free," i.e., no other object should be positioned above the seat to prevent the rod-shaped article from being positioned thereon. The rod-shaped article may be moved to the drum seat, for example, from another drum or from a conveyor. Thus, when the rod-shaped article is positioned in the seat, the first half coil and the second half coil are preferably separated from each other and in the second operating position, so that the volume above the seat is "free" and the rod-shaped article can be positioned thereon without any obstructions. When the rod-shaped article is in the seat, the first half coil and the second half coil are moved to the first operating position, allowing detection of the susceptor characteristics. Therefore, the actuator moves the first half coil or the second half coil until the half winding of the first half coil corresponds to the complementary half winding of the second half coil. The control unit commands the actuator to move the second half coil until the first operating position is reached. The control unit's command may be triggered by an additional sensor that senses the presence or absence of a rod-shaped article in the seat. Therefore, when the sensor senses the presence of a rod-shaped article, it sends a signal to the control unit, which in turn sends a signal to the actuator to bring the first half coil and the second half coil to the first operating position, which may be detected by the inductive sensor. Alternatively, the command sent by the control unit to the actuator is synchronized with the rotation of the drum. While the drum rotates, the control unit is adapted to receive or determine the angular velocity of the drum and the insertion point of the rod-shaped article into the drum. From this information, the control unit may calculate the angular position of each rod-shaped article in the drum. The control unit may command an actuator in a seat where the inductive sensor resides to move the first half-coil and the second half-coil from the second operating position to the first operating position at a given frequency.

[0054] Preferably, the seat includes a receiving surface, a portion of the outer surface of the drum, and the first half-coil is located below the receiving surface of the seat. Preferably, the first half-coil is located below the receiving surface of the seat on which the rod-shaped article is positioned. The second half-coil preferably moves from a first operating position in which the second half-coil is located above the seat to a second operating position in which the second half-coil is not above the seat. In the second operating position, the second half-coil is shifted toward the end of the seat. For example, the second half-coil is moved toward the side of the drum. The movement of the second half-coil is preferably along a direction parallel to the seat axis.

[0055] According to another aspect, the present invention relates to an inspection apparatus for quality control of rod-shaped articles, the apparatus comprising a drum including a plurality of seats, each seat of the plurality adapted to receive a rod-shaped article. The inspection apparatus may include an inductive sensor located in one of the plurality of seats, the inductive sensor including a coil defining an interior volume large enough to receive an end of the rod-shaped article therein, the inductive sensor adapted to sense a characteristic of a susceptor within the rod-shaped article. The inspection apparatus may include a compressed air system aligned with the plurality of seats. The inspection apparatus may include an actuator adapted to activate the compressed air system to blow air when the rod-shaped article is positioned within the seat and presses the rod-shaped article within the coil.

[0056] For example, the compressed air system may include a nozzle adapted to discharge a stream of compressed air. The main direction of the stream of compressed air is preferably parallel to the longitudinal axis of the seat. Thus, the stream of compressed air preferably impinges on one of the ends of the rod-shaped article and pushes it towards the coil. The coil is preferably aligned with the seat, i.e., the longitudinal axis of the coil is preferably parallel to or coincides with the longitudinal axis of the rod-shaped article. The longitudinal axis of the coil is preferably parallel to the mean axis of the stream of compressed air.

[0057] The compressed air system preferably includes a second nozzle for discharging a compressed air flow opposite to the first compressed air flow to push the rod-shaped article out of the coil. The second nozzle preferably faces the first nozzle at a distance. The distance is preferably longer than the length of the rod-shaped article. The first and second nozzles are preferably located on opposite sides of the coil.

[0058] The size of the interior volume of the coil is such that a rod-shaped article can be inserted at least partially into the coil from one of its ends.

[0059] In this embodiment, the drum and rod-like articles are the same as in the previous embodiment, and their properties are not repeated here. Additionally, the properties measured for the susceptor are as described in the previous embodiment.

[0060] In this embodiment, the relative movement between the rod-shaped article and the inductive sensor includes at least movement of the rod-shaped article toward the coil of the inductive sensor. Preferably, the relative movement includes only movement of the rod-shaped article toward the coil of the inductive sensor. Preferably, the coil of the inductive sensor is fixed and moves with the outer surface of the drum, i.e., the coil is stationary relative to the outer surface of the drum. Thus, the coil rotates with the outer surface of the drum. Preferably, the rod-shaped article is positioned within a seat. After positioning the seat, the rod-shaped article is inserted into the coil of the inductive sensor by a compressed air flow.

[0061] Insertion of the rod-shaped article may be performed, for example, via the discharge of a stream of compressed air which is performed when the rod-shaped article is positioned in its seat on the drum.

[0062] Preferably, the test includes a control unit. Preferably, the control unit is in communication with the inductive sensor. Preferably, the inductive sensor is adapted to generate one or more signals in response to properties of the susceptor. These properties may include the presence or absence of a susceptor, the dimensions of the susceptor, and the mass of the material from which the susceptor is formed. Preferably, the control unit is in communication with the inductive sensor.

[0063] The inductive sensor is preferably adapted to emit a signal that represents a parametric function of the impedance of the coil.

[0064] Preferably, the inspection device includes a control unit adapted to command the compressed air system to discharge a compressed air flow when a rod-shaped article is on the seat. The seat may be empty when no rod-shaped article is located therein. Alternatively, the seat may contain a rod-shaped article located therein. When a rod-shaped article is located in the seat, the compressed air system is preferably activated, i.e., the compressed air flow is preferably discharged. In this way, the compressed air flow can push the rod-shaped article within the coil of the inductive sensor. The rod-shaped article may be moved to the drum seat, for example, from another drum or from a conveyor. When a rod-shaped article is in the seat, the control unit preferably commands the compressed air system to discharge an air flow. The control unit's command may be triggered by an additional sensor that detects the presence or absence of a rod-shaped article in the seat. Thus, when the sensor detects the presence of a rod-shaped article, the sensor sends a signal to the control unit, which in turn sends a signal to the compressed air system to discharge an air flow to push the rod-shaped article into the coil. While the drum rotates, the control unit is adapted to receive or determine the angular velocity of the drum and the insertion point of the rod-shaped articles into the drum. From this information, the control unit may calculate the angular position of each rod-shaped article within the drum. The control unit may command the compressed air system at a predetermined frequency to exhaust airflow within the seat only when the seat is occupied by a rod-shaped article.

[0065] There may be a single compressed air system for all of the plurality of seats. The compressed air system may be located on a side of the outer surface of the drum. Preferably, the compressed air system faces the first or second side of the drum. The compressed air system may be stationary, i.e., not rotate with the drum. The compressed air system may discharge a compressed air stream into a single seat at each time interval. However, the compressed air system may discharge a compressed air stream into some of the plurality of seats while passing in front of the nozzle of the compressed air system. The nozzle is stationary while the seats move in front of the nozzle due to the rotation of the drum. Preferably, a new air stream is discharged each time a new seat is in front of the nozzle.

[0066] In any embodiment, the drum has a rotation axis, and each seat in the plurality defines a seat axis, with the seat axes and rotation axes preferably being parallel to one another. All seats preferably have seat axes parallel to the drum's rotation axis. All seat axes preferably are parallel to one another. This may result in the rod-shaped article having a longitudinal axis parallel to the rotation axis when the rod-shaped article is positioned within the seat. To determine the properties of the susceptor, relative movement between the rod-shaped article and the coil (e.g., either movement of the half coil, or movement of the rod-shaped article, or both) is required. A configuration in which the rod-shaped articles are parallel to the drum's rotation axis maximizes the number of rod-shaped articles that the drum can simultaneously host.

[0067] In a preferred embodiment of the present invention, the length of the coil is comprised between 20 mm and 40 mm. The length of the coil is preferably longer than the length of the susceptor so that the entire susceptor can be inserted into the coil. The length of the coil is taken along the coil axis.

[0068] The inspection device preferably includes a control unit electrically connected to the inductive sensor. The control unit is preferably adapted to receive a signal from the inductive sensor and compare the signal with a threshold value. The inductive sensor preferably measures the impedance of the system formed by the coil and the susceptor, or a parameter function of the impedance of the coil. In the susceptor made of a conductive material, eddy currents are generated, which in turn form a magnetic field. The parameter function of the impedance measured by the inductive sensor depends on the characteristics of the susceptor. In some embodiments of the inductive sensor, the inductive sensor measures resistance. In particular, the inductive sensor is adapted to measure the equivalent series resistance of the susceptor. A susceptor is preferably considered acceptable if its resistance measured by the inductive sensor is comprised between 200 milliohms and 500 milliohms. Due to the fact that the composition of the susceptor is known, comparison with the threshold value allows the characteristics of the susceptor to be determined.

[0069] When the susceptor is absent from the rod-like article, there is no change in the impedance of the coil, and it is assumed that there are generally no other conductive objects contained within the rod-like article, except for the susceptor.

[0070] More preferably, the control unit is adapted to calculate the length of the susceptor located within the rod-shaped article. The length of the susceptor may be calculated by checking the variation of the signal emitted by the inductive sensor according to the position of the rod-shaped article within the coil. The signal emitted by the inductive sensor depends on the impedance of the system coil and the susceptor. This impedance reaches a maximum (or minimum) level when the entire susceptor enters the interior of the coil and begins to decrease (or increase) as soon as the end of the susceptor exits the coil. By comparing this signal with the position of the rod-shaped article within the coil, it is possible to determine the exact length of the susceptor.

[0071] A rejection device is preferably provided that is adapted to reject the rod-shaped article based on a signal emitted by the inductive sensor. If the inductive sensor detects that one of the characteristics of the susceptor inside the rod-shaped article is outside of specifications, for example, that the susceptor is absent or that the length of the susceptor is too short or too long, the rod-shaped article is preferably not processed further. Rod-shaped articles containing "defective" susceptors are transferred to a rejection drum that is different from the drum to which rod-shaped articles containing valid susceptors are transferred. The control unit preferably controls a suction system that keeps the rod-shaped articles in their seats in such a way that rod-shaped articles containing defective susceptors are ejected from the seats differently from rod-shaped articles containing valid susceptors. The control unit preferably distinguishes between valid susceptors and defective susceptors. The distinction is preferably based on the characteristics of the susceptor detected by the inductive sensor.

[0072] The drum preferably includes a plurality of inductive sensors, one for each of a plurality of seats, so that multiple rod-like articles can be checked quickly.

[0073] The coil preferably has a diameter comprised between 10 and 20 millimeters. The diameter of the coil considered in this specification is the inner diameter of the coil, i.e. the diameter available for the insertion of a rod-shaped object. The size of the coil is such that a rod-shaped object can be inserted.

[0074] The seat defines a seat axis, and the coil defines a coil axis, and the coil axis and seat axis are preferably parallel to each other. To measure the properties of the susceptor, a rod-shaped article is inserted into the coil. When the coil and the rod-shaped article have their respective axes parallel to each other, the relative movement performed between the coil and the rod-shaped article is a simple linear movement. Therefore, the mechanical structure is relatively simple.

[0075] According to another aspect, the present invention relates to an inspection apparatus comprising a first drum including a first plurality of seats, each seat of the first plurality adapted to receive a rod-shaped article, the first drum including the first plurality of seats defining a first outer surface. The inspection apparatus may also include a first inductive sensor positioned in one of the seats of the first plurality, the first inductive sensor including a first coil defining an internal volume large enough to receive a first end of the rod-shaped article therein, the first inductive sensor adapted to sense a characteristic of a first susceptor within the rod-shaped article. Preferably, the first coil includes a first half-coil and a second half-coil, which are movable from a first operating position in which the first half-coil and the second half-coil contact each other to form a first coil through which current can flow, to a second operating position in which the first half-coil and the second half-coil are separated from each other and through which no current can flow, or vice versa. Preferably, the first half-coil is located below the first outer surface of the first drum, and the second half-coil is located above the first outer surface of the first drum. The inspection apparatus may also include a first actuator adapted to move the first and second half-coils of the first coil from a first operating position to a second operating position and vice versa within the first drum. The inspection apparatus may also include a second drum including a second plurality of seats, each seat of the second plurality adapted to receive a rod-shaped article, the second drum defining a second outer surface. The inspection apparatus may also include a second inductive sensor located in one of the seats of the second plurality, the second inductive sensor including a second coil defining an interior volume large enough to receive a second end of the rod-shaped article therein, the second inductive sensor adapted to sense a characteristic of a second susceptor within the rod-shaped article.The second coil preferably includes a first half-coil and a second half-coil, and the first half-coil and the second half-coil are movable from a first operating position, in which the first half-coil and the second half-coil are in contact with each other to form a second coil through which a current can flow, to a second operating position, in which the first half-coil and the second half-coil are separated from each other and through which no current can flow, or vice versa. The first half-coil of the second coil is preferably located below the second outer surface, and the second half-coil of the second coil is preferably located above the second outer surface. The inspection device may also include a second actuator adapted to move the first half-coil and the second half-coil of the second coil from the first operating position to the second operating position, or vice versa, within the second drum. The first drum and the second drum are preferably substantially in contact to enable transfer of rod-shaped articles from the first drum to the second drum.

[0076] The inspection apparatus essentially comprises two drums, a first drum and a second drum, each of which is realized according to the first aspect of the present invention described above. When the rod-shaped article includes a first susceptor and a second susceptor, two drums are preferably used. The first susceptor and the second susceptor are preferably located at two opposite distal ends of the rod-shaped article. Thus, the first drum having the first inductive sensor is used to inspect the first end of the rod-shaped article where the first susceptor is present. The second drum having the second inductive sensor is used to inspect the second end of the rod-shaped article where the second susceptor is present. In the first drum, the relative movement between the rod-shaped article and the coil is along a first axis, while in the second drum, the relative movement between the rod-shaped article and the coil is along an axis parallel to the first axis but in the opposite direction. After inspection in the first drum, in which the first susceptor is inspected, the rod-shaped article is preferably transferred to the second drum. Preferably, the transfer is performed only if the first susceptor is free of defects. The transfer is performed according to standard on-site methods. Therefore, a fast and thorough check of both the first and second susceptors is achieved.

[0077] According to a further aspect, the present invention relates to an inspection apparatus comprising a first drum including a first plurality of seats, each seat of the first plurality adapted to receive a rod-shaped article. The inspection apparatus preferably comprises a first inductive sensor located in one of the seats of the first plurality, the first inductive sensor including a first coil defining an interior volume large enough to receive a first end of the rod-shaped article therein, the first inductive sensor adapted to sense a characteristic of a first susceptor within the rod-shaped article. The inspection apparatus preferably comprises a first compressed air system aligned with the first plurality of seats. The inspection apparatus preferably comprises a first actuator adapted to activate the first compressed air system to blow air and force it into the inside of the first coil of the first drum when a rod-shaped article is located within the first plurality of seats. The inspection apparatus preferably comprises a second drum including a second plurality of seats, each seat of the second plurality adapted to receive a rod-shaped article. The inspection apparatus preferably includes a second inductive sensor positioned in one of the second plurality of seats, the second inductive sensor including a second coil defining an interior volume large enough to receive the second end of the rod-shaped article therein, the second inductive sensor being adapted to sense a characteristic of the first susceptor within the rod-shaped article. The inspection apparatus preferably includes a second compressed air system aligned with the second plurality of seats. The inspection apparatus preferably includes a second actuator adapted to activate the second compressed air system to blow air and force it into the inside of the second coil of the second drum when the rod-shaped article is located within the second plurality of seats. The first drum and the second drum are preferably substantially contiguous to enable transfer of the rod-shaped article from the first drum to the second drum.

[0078] The inspection apparatus essentially comprises two drums, a first drum and a second drum, each of which is realized according to the second aspect of the present invention described above. Two drums are used when the rod-shaped article includes a first susceptor and a second susceptor. The first susceptor and the second susceptor are preferably located at two opposite distal ends of the rod-shaped article. Thus, the first drum having the first inductive sensor is used to inspect the first end of the rod-shaped article where the first susceptor is present. The second drum having the second inductive sensor is used to inspect the second end of the rod-shaped article where the second susceptor is present. Thus, in the first drum, the relative movement between the rod-shaped article and the coil is along a first axis, while in the second drum, the relative movement between the rod-shaped article and the coil is along an axis parallel to the first axis but in the opposite direction. After inspection in the first drum, the rod-shaped article is preferably transferred to the second drum. Preferably, the transfer is performed only if the first susceptor is free of defects. The transfer is performed according to standard on-site methods. Therefore, a fast and thorough check of both the first and second susceptors is achieved.

[0079] "Impedance" is a generalization of resistance with a complex value. Impedance Z is a complex number that represents V (voltage) / I (current). For an ideal inductor L such as a coil, the impedance Z L is given by the following formula:

number

[0080] TIFF0007778780000002.tif13170

[0081] TIFF0007778780000003.tif8170

[0082] Hereinafter, the term "rod-shaped article" may refer to any element that may be included within an aerosol-generating article, or it may refer to the complete aerosol-generating article. Such elements are well known in the art and will not be described in further detail below. For example, such a rod-shaped article may include a filter plug, a heat source, a tobacco rod, a charcoal element, etc. Preferably, the rod-shaped article is a plant material-containing article, in particular a tobacco-containing article. The tobacco article may include tobacco cut filler or aerosol-forming reconstituted tobacco. The article may comprise a tobacco rod that is burned or heated. A rod-shaped article according to the present invention may be a complete assembled aerosol-generating article, or may be an element of an aerosol-generating article that is combined with one or more other components to provide an assembled aerosol-generating article for producing an aerosol, such as, for example, a consumable part of a heated smoking device.

[0083] The components of the aerosol-generating article preferably include a tobacco-containing material that includes volatile tobacco flavor compounds that are released from the aerosol-generating substrate upon heating.

[0084] Preferably, the rod-shaped article may include a heat source or a volatile flavor-generating component, such as a menthol capsule, a charcoal element, or a susceptor.

[0085] Furthermore, the rod-shaped article may include multiple components of an aerosol-generating article combined together, or even something other than an aerosol-generating article.

[0086] As used herein, the term "susceptor" refers to a material capable of converting electromagnetic energy into heat. When placed in an alternating electromagnetic field, eddy currents are induced in the susceptor, and hysteresis losses occur, causing the susceptor to heat. Because the susceptor is placed in thermal contact with or in close thermal proximity to the aerosol-forming substrate, the aerosol-forming substrate is heated by the susceptor, thereby forming an aerosol. The susceptor is preferably disposed in direct physical contact with the aerosol-forming substrate, for example, within the aerosol-forming tobacco substrate.

[0087] The susceptor may be formed from any material that can be inductively heated to a temperature sufficient to generate an aerosol from the aerosol-forming substrate. A preferred susceptor may include or consist of a ferromagnetic material (e.g., a ferromagnetic alloy, ferritic iron, or ferromagnetic steel or stainless steel). A suitable susceptor may be or include aluminum. A preferred susceptor may be heated to temperatures exceeding 250 degrees Celsius. A suitable susceptor may include a non-metallic core having a metal layer disposed thereon (e.g., a metal track formed on the surface of a ceramic core). The susceptor may have a protective outer layer, such as a protective ceramic or glass layer, encapsulating the susceptor. The susceptor may include a protective coating formed of glass, ceramic, or an inert metal formed over a core of susceptor material.

[0088] The susceptor may be a multi-material susceptor and may include a first susceptor material and a second susceptor material. The first susceptor material is disposed in close physical contact with the second susceptor material. The second susceptor material preferably has a Curie temperature below 500°C. The first susceptor material is preferably used primarily to heat the susceptor when it is placed in an oscillating electromagnetic field. Any suitable material may be used. For example, the first susceptor material may be aluminum or an iron-based material such as stainless steel. The second susceptor material is preferably used primarily to indicate when the susceptor has reached a specific temperature (the Curie temperature of the second susceptor material). The Curie temperature of the second susceptor material can be used to regulate the temperature of the entire susceptor during operation. Therefore, the Curie temperature of the second susceptor material should be below the ignition point of the aerosol-forming substrate. Suitable materials for the second susceptor material may include nickel and certain nickel alloys.

[0089] The susceptor preferably has the form of a filament, rod, sheet, or strip. When the susceptor has a constant cross-section, for example, a circular cross-section, the outline preferably has a width or diameter of about 1 mm to about 5 mm. When the susceptor has a sheet or strip shape, the sheet or strip preferably has a rectangular shape with a width of about 2 mm to about 8 mm, more preferably about 3 mm to about 5 mm (e.g., 4 mm), and a thickness of about 0.03 mm to about 0.15 mm, more preferably about 0.05 mm to about 0.09 mm (e.g., 0.07 mm).

[0090] Preferably, the rod-shaped article may have a length of about 5 millimeters to about 20 millimeters, preferably about 8 millimeters to about 16 millimeters (e.g., about 12 millimeters). In some cases, the rod-shaped article may have a length of about 40 millimeters to about 85 millimeters.

[0091] In the following, the term "length" refers to the length of a rod-shaped article along its longitudinal axis, unless otherwise specified.

[0092] In the following, the term "rod-like" refers to a generally cylindrical element of substantially cylindrical, oval or elliptical cross section, although other prismatic forms with different cross sections are also possible.

[0093] As used herein, an "aerosol-generating article" is any article that generates an inhalable aerosol when the aerosol-forming substrate is heated. This term includes articles that include an aerosol-forming substrate that is heated by an external heat source, such as an electric heating element. The aerosol-forming article may be a non-combustible aerosol-generating article, which is an article that releases a volatile compound without combustion of the aerosol-forming substrate. The aerosol-forming article may also be a heated aerosol-generating article, which is an aerosol-generating article that includes an aerosol-forming substrate that is intended to be heated, rather than burned, to release a volatile compound that can form an aerosol. This term includes articles that include an aerosol-forming substrate and an integrated heat source (e.g., a combustible heat source).

[0094] The aerosol-generating article may comprise a mouthpiece element, which may be located at the mouth end or downstream end of the aerosol-generating article.

[0095] The aerosol-generating article may comprise at least one filter element.

[0096] The filter segment may be a cellulose acetate filter plug made from cellulose acetate tow. The filter segment may have low or very low particulate filtration efficiency. The filter segment may be longitudinally spaced from the aerosol-forming substrate. The filter segment may have a longitudinal length of 5 millimeters to about 14 millimeters. The filter segment may have a length of about 7 millimeters.

[0097] The plurality of elements of the aerosol-generating article may include at least one of a support element and an aerosol-cooling element.

[0098] The aerosol-generating article preferably comprises a wrapper around the multiple elements of the aerosol-generating article in the form of a rod. The wrapper may comprise at least one of paper and foil.

[0099] As used herein, the term "aerosol-forming substrate" refers to a substrate formed from or including an aerosol-forming material capable of releasing volatile compounds upon heating to generate an aerosol. The aerosol-forming substrate may contain tobacco material, or may contain non-tobacco material, or may contain a combination of both tobacco and non-tobacco material. The aerosol-forming substrate may be a cellulosic material impregnated with nicotine, and preferably includes one or more flavors. Advantageously, the aerosol-forming substrate comprises a tobacco material, preferably a homogenized tobacco material, preferably a tobacco material that includes one or more aerosol formers. As used herein, the term "homogenized tobacco material" refers to a material formed by agglomerating particulate tobacco.

[0100] The aerosol-forming substrate preferably contains volatile tobacco flavor compounds that are released from the aerosol-forming substrate upon heating. The aerosol-forming substrate may comprise or consist of a blended tobacco cut filler, or may contain homogenized tobacco material. The homogenized tobacco material may be formed by agglomerating particulate tobacco. The aerosol-forming substrate may additionally contain a non-tobacco-containing material, for example, a homogenized plant-derived material other than tobacco.

[0101] The aerosol-forming substrate is preferably a (preferably crimped) tobacco sheet comprising tobacco material, fiber, binder, and aerosol former. The tobacco sheet is preferably a cast leaf. Cast leaf is a form of reconstituted tobacco formed from a slurry containing tobacco particles, fiber particles, aerosol former, binder, and, for example, flavors.

[0102] The tobacco particles may be in the form of tobacco dust having particles on the order of 30 micrometers to 250 micrometers, preferably on the order of 30 micrometers to 80 micrometers, or on the order of 100 micrometers to 250 micrometers, depending on the desired sheet thickness and casting gap, which typically defines the thickness of the sheet.

[0103] The size of tobacco particles refers to the Dv95 size of tobacco particles in volume distribution.

[0104] The fiber particles may also include tobacco stem material, petioles or other tobacco plant material, and other cellulosic fibers (such as wood fibers with low lignin content). The fiber particles may be selected based on the desire to produce sufficient tensile strength in the cast leaf at low lignin content, for example, about 2 percent to 15 percent. Alternatively, fibers such as plant fibers may be used in conjunction with or in place of the above-mentioned fiber particles, including hemp and bamboo.

[0105] The aerosol former included in the slurry forming the cast leaf or used with other aerosol-forming substrates may be selected based on one or more characteristics. Functionally, the aerosol former provides a mechanism for volatilizing the aerosol former when heated above the aerosol former's specific volatilization temperature, enabling the aerosol former to deliver nicotine, flavorings, or both in an aerosol state. Different aerosol formers typically vaporize at different temperatures. The aerosol former may be any suitable known compound or mixture of compounds that facilitates the formation of a high-density, stable aerosol during use and that is substantially resistant to thermal decomposition at the operating temperatures of the induction heating device to be used with the inductively heatable tobacco substrate. The aerosol former may be selected based on its ability to remain stable at or near room temperature, for example, but to volatilize at higher temperatures, e.g., between 40°C and 450°C.

[0106] The aerosol former may also have humectant-type properties that help maintain a desired amount of moisture in the aerosol-forming substrate when the substrate comprises tobacco-derived products, particularly when the substrate contains tobacco particles. In particular, some aerosol formers are hygroscopic materials that function as humectants, i.e., materials that help keep humectant-containing tobacco substrates moist.

[0107] One or more aerosol formers may be combined to take advantage of one or more properties of the combined aerosol formers, for example, triacetin may be combined with glycerin and water to take advantage of triacetin's ability to carry active ingredients and glycerin's humectant properties.

[0108] The aerosol former may be selected from polyols, glycol ethers, polyol esters, esters, fatty acids, and may include one or more of the following compounds: glycerin, erythritol, 1,3-butylene glycol, tetraethylene glycol, triethylene glycol, triethyl citrate, propylene carbonate, ethyl laurate, triacetin, meso-erythritol, diacetin mixtures, diethyl suberate, triethyl citrate, benzyl benzoate, benzyl phenylacetate, ethyl vanillate, tributyrin, lauryl acetate, lauric acid, myristic acid, propylene glycol.

[0109] The aerosol-forming substrate may contain other additives and ingredients (such as flavourings). Preferably the aerosol-forming substrate contains nicotine and at least one aerosol former.

[0110] Aerosol-generating articles according to the present invention may be in the form of filtered combustible cigarettes or other smoking articles in which tobacco material is combusted to produce smoke.

[0111] Preferably, the aerosol-generating article may be substantially cylindrical in shape. The aerosol-generating article may be substantially elongated. The aerosol-generating article may have a length and a perimeter substantially perpendicular to the length. The aerosol-generating article may have an overall length of about 30 millimeters to about 100 millimeters. The aerosol-generating article may have an outer diameter of about 5 millimeters to about 12 millimeters.

[0112] The present invention is defined in the claims. However, the following provides a non-exhaustive list of non-limiting examples. Any one or more of the features of these examples may be combined with any one or more features of any other example, embodiment, or aspect described herein. [Example]

[0113] Example 1: An inspection device for quality control of rod-shaped articles, comprising: a drum including a plurality of seats, each seat of the plurality adapted to receive a rod-shaped article, the drum defining an outer surface; an inductive sensor located at one of the plurality of locations, the inductive sensor including a coil defining an interior volume large enough to receive an end of the rod-shaped article therein, the inductive sensor adapted to sense a characteristic of a susceptor within the rod-shaped article; the coil includes a first half-coil and a second half-coil, the first half-coil and the second half-coil being movable from a first operating position in which the first half-coil and the second half-coil are in contact with each other to form a coil through which a current can flow to a second operating position in which the first half-coil and the second half-coil are separated from each other, and vice versa; a first half coil positioned below the outer surface of the drum and a second half coil positioned above the outer surface of the drum; an actuator adapted to move the first half-coil and the second half-coil from the first operating position to the second operating position and vice versa.

[0114] Example 2: An inspection device according to example 1, comprising a control unit adapted to command the actuator to move the first half-coil or the second half-coil from the second operating position to the first operating position when the rod-shaped article is on the seat.

[0115] Example 3: The inspection device according to example 1 or example 2, wherein the seat includes a receiving surface, a portion of the outer surface of the drum, and the first half coil is positioned below the receiving surface of the seat.

[0116] Example 4: An inspection device according to one or more of Examples 1-3, wherein the outer surface of the drum includes one or more conductive strips that enable sliding of the second half coil towards and away from the first half coil and enable electrical connection between the first half coil and the second half coil.

[0117] Example 5: The inspection device according to one or more of Examples 1 to 4, wherein the actuator comprises a pneumatic actuator.

[0118] Example 6: An inspection device according to example 5, wherein the pneumatic actuator comprises a piston fixed to the second half coil.

[0119] Example 7: An inspection device according to one or more of Examples 1 to 6, wherein the coil defines a coil axis, and the movement of the first half coil and the second half coil from the first operating position to the second operating position, and vice versa, is linear.

[0120] Example 8: An inspection device according to Example 7, wherein the linear movement is a movement in a direction parallel to the coil axis.

[0121] Example 9: An inspection device according to example 7 or example 8, wherein the linear movement is a linear movement parallel to the bearing axis.

[0122] Example 10: An inspection apparatus according to one or more of Examples 1 to 9, including a control unit in communication with the inductive sensor, the control unit being adapted to receive a signal from the inductive sensor relative to the characteristic of the susceptor.

[0123] Example 11: An inspection device for quality control of rod-shaped articles, comprising: a drum including a plurality of seats, each seat of the plurality adapted to receive a rod-shaped article; an inductive sensor located at one of the plurality of locations, the inductive sensor including a coil defining an interior volume large enough to receive an end of the rod-shaped article therein, the inductive sensor adapted to sense a characteristic of a susceptor within the rod-shaped article; a compressed air system aligned with the plurality of seats; an actuator adapted to activate the compressed air system to blow air when the rod-shaped article is positioned within the seat to push the rod-shaped article inside the coil.

[0124] Example 12: The inspection device according to example 11, wherein the seat defines a seat axis, and the compressed air system includes a nozzle adapted to discharge a stream of compressed air substantially parallel to the seat axis.

[0125] Example 13: An inspection device according to one or more of Examples 1 to 12, wherein the drum has an axis of rotation, and each seat of the plurality defines a seat axis, and the longitudinal axis and the seat axis are parallel to one another.

[0126] Example 14: An inspection device according to one or more of Examples 1 to 13, wherein the coil has a coil axis, and each seat of the plurality defines a seat axis, and the coil axis and the seat axis are parallel to each other.

[0127] Example 15: An inspection device according to one or more of Examples 1 to 14, wherein the length of the coil is between 20 millimeters and 40 millimeters.

[0128] Example 16: An inspection device according to one or more of Examples 1 to 15, comprising a control unit electrically connected to the inductive sensor, the control unit adapted to receive a signal from the inductive sensor and compare the signal with a threshold value.

[0129] Example 17: An inspection apparatus according to one or more of Examples 1 to 16, wherein the characteristic of the susceptor is a length of the susceptor.

[0130] Example 18: The inspection device according to example 16 or example 17, wherein the control unit is adapted to calculate a length of the susceptor located within the rod-shaped article.

[0131] Example 19: An inspection device according to one or more of Examples 1 to 18, comprising a rejection device adapted to reject rod-shaped articles based on a signal emitted by the inductive sensor.

[0132] Example 20: The inspection device according to one or more of Examples 1 to 19, wherein the drum comprises a plurality of inductive sensors, one sensor for each seat of the plurality of seats.

[0133] Example 21: An inspection device according to one or more of Examples 1 to 20, wherein the coil has a diameter between 10 millimeters and 20 millimeters.

[0134] Example 22: The inspection device according to one or more of Examples 1 to 21, wherein each seat of the plurality defines a seat axis, and the seat axes are parallel to one another.

[0135] Example 23: A kit comprising: a rod-shaped article including a susceptor; A kit comprising: a testing device according to one or more of Examples 1 to 22.

[0136] Example 24: A kit according to Example 23, wherein the rod-shaped article comprises the components of the aerosol-generating article.

[0137] Example 25: A kit according to Example 23 or Example 24, wherein the susceptor is in contact with an aerosol-forming material.

[0138] Example 26: A kit according to Example 25, wherein the aerosol-forming material comprises tobacco material.

[0139] Example 27: An inspection device, a first drum including a first plurality of seats, each seat of the first plurality adapted to receive a rod-shaped article, the first drum defining a first outer surface; a first inductive sensor positioned at one of the first plurality of locations, the first inductive sensor including a first coil defining an interior volume large enough to receive a first end of the rod-shaped article therein, the first inductive sensor adapted to sense a characteristic of a first susceptor in the rod-shaped article; the first coil includes a first half-coil and a second half-coil, the first half-coil and the second half-coil being movable from a first operating position in which the first half-coil and the second half-coil are in contact with each other to form a first coil through which a current can flow to a second operating position in which the first half-coil and the second half-coil are separated from each other, and vice versa; a first half coil positioned below the first outer surface of the first drum and a second half coil positioned above the first outer surface of the first drum; a first actuator adapted to move the first half-coil and the second half-coil of the first coil from the first operating position to the second operating position and vice versa within the first drum; a second drum including a second plurality of seats, each seat of the second plurality adapted to receive a rod-shaped article, the second drum defining a second outer surface; a second inductive sensor located at a second plurality of locations, the second inductive sensor including a second coil defining an interior volume large enough to receive a second end of the rod-shaped article therein, the second inductive sensor adapted to sense a characteristic of a second susceptor in the rod-shaped article; the second coil includes a first half-coil and a second half-coil, the first half-coil and the second half-coil being movable from a first operating position in which the first half-coil and the second half-coil are in contact with each other to form a second coil through which a current can flow to a second operating position in which the first half-coil and the second half-coil are separated from each other and no current can flow, and vice versa; a first half coil of the second coil located below the second outer surface and a second half coil of the second coil located above the second outer surface; a second actuator adapted to move the first half-coil and the second half-coil of the second coil from the first operating position to the second operating position and vice versa within the second drum; The first drum and the second drum are substantially tangent to allow transfer of the rod-shaped article from the first drum to the second drum.

[0140] Example 29: An inspection device, a first drum including a first plurality of seats, each seat of the first plurality adapted to receive a rod-shaped article; a first inductive sensor located at one of the first plurality of locations, the first inductive sensor including a first coil defining an interior volume large enough to receive a first end of the rod-shaped article therein, the first inductive sensor adapted to sense a characteristic of a first susceptor in the rod-shaped article; a first compressed air system aligned with the seats of the first plurality; a first actuator adapted to activate the first compressed air system to blow air and force it into the inside of the first coil of the first drum when the rod-shaped article is located within the seats of the first plurality; a second drum including a second plurality of seats, each seat of the second plurality adapted to receive a rod-shaped article; a second inductive sensor positioned at one of the second plurality of locations, the second inductive sensor including a second coil defining an interior volume large enough to receive the second end of the rod-shaped article therein, the second inductive sensor adapted to sense a characteristic of a second susceptor in the rod-shaped article; a second compressed air system aligned with the seats of the second plurality; a second actuator adapted to activate the second compressed air system to blow air and push the rod-shaped article into the second coil of the second drum when the rod-shaped article is located within the seats of the second plurality of seats; The first drum and the second drum are substantially contiguous to allow transfer of the rod-shaped article from the first drum to the second drum.

[0141] Example 30: An apparatus for manufacturing an aerosol-generating article comprising a rod-shaped element including a susceptor, said apparatus comprising an inspection device according to any one of Examples 1 to 29.

[0142] Example 31: A device according to example 30, wherein the rod-shaped element comprises an aerosol-forming material.

[0143] Example 32: A method for inspecting a rod-shaped article, comprising: Providing an inspection device according to Examples 1 to 10; Positioning the rod-shaped article within a seat on the drum, the first half-coil and the second half-coil being in a second operating position; moving the first half-coil and the second half-coil into a first operating position; and sensing a property of the susceptor.

[0144] Example 33: A method for inspecting a rod-shaped article, comprising: Providing an inspection device according to Examples 11 to 22; Positioning a rod-shaped article within a seat on a drum; forcing the rod-shaped article into the coil with an air stream; and sensing a property of the susceptor. The embodiments will now be further described with reference to the figures. [Brief explanation of the drawings]

[0145] [Figure 1] FIG. 1 is a schematic perspective view, partially in section, of a rod-shaped article including a susceptor to be inspected in accordance with the present invention. [Figure 2] FIG. 2 is a cross-sectional side view of the rod-shaped article of FIG. [Figure 3] FIG. 3 is a schematic perspective view of a first configuration of an inspection device according to a first embodiment of the present invention. [Figure 4]FIG. 4 is a schematic perspective view of an inspection device according to a second embodiment of the present invention. [Figure 5] 5A to 5C are schematic top views of the inspection apparatus of FIG. 4 in a time sequence. [Figure 6] FIG. 6 shows the sequence of steps for the functioning of the inductive sensor present in the test device of the present invention. [Figure 7] FIG. 7 is a detailed cross-sectional view of the coil of the inspection device of FIG. 3, FIG. 4, or FIG. [Figure 8] FIG. 8 is a front view of the coil of FIG. [Figure 9] FIG. 9 is a side view of another embodiment of a rod-shaped article to be inspected in accordance with the present invention. [Figure 10] FIG. 10 shows a third embodiment of the inspection device according to the present invention. [Figure 11] FIG. 11 shows two enlarged views of two details of FIG. 10 in two different embodiments. [Figure 12] FIG. 12 shows two enlarged views of two details of FIG. 10 in two different embodiments. [Figure 13] 13 shows two cross-sectional views of the coil of the first embodiment of the inspection device of FIG. 3 in a first operating position and a second operating position, respectively. [Figure 14] 14 shows two cross-sectional views of the coil of the first embodiment of the inspection device of FIG. 3 in a first operating position and a second operating position, respectively.

[0146] 1 and 2, an example of a rod-shaped article is generally designated 60. Preferably, rod-shaped article 60 comprises several components of an aerosol-generating article (e.g., a complete aerosol-generating article).

[0147] The aerosol-generating article 60 comprises a plurality of elements assembled, for example, in the form of a rod. The plurality of elements may comprise a plug element 11, an aerosol-forming substrate 10 in the form of a tobacco plug, a susceptor material 12 positioned within the aerosol-forming substrate 10, a hollow acetate tube 16, a further hollow acetate tube 18, a mouthpiece 2, and an outer wrapper 22. The aerosol-generating article 60 comprises a mouth end 24 and a distal end 26. The rod-shaped article 60 defines a longitudinal axis 61.

[0148] The above-listed elements preferably extend one after the other along the longitudinal axis 61 of the rod-shaped article 60. They preferably all have the same diameter.

[0149] The cross section of the rod-shaped article 60 along a plane perpendicular to its longitudinal axis 61 is preferably circular.

[0150] The rod-shaped article 60 has a preferably substantially cylindrical outer surface 13 extending along a longitudinal axis 61. The longitudinal axis 61 of the rod-shaped article 60 may correspond to the axis of a cylinder.

[0151] The aerosol-forming substrate 10 may comprise a homogenized tobacco material.

[0152] The susceptor 12 is preferably in thermal contact with the aerosol-forming substrate 10 so that when the susceptor is inductively heated, heat is transferred to the aerosol-forming substrate 10, thereby emitting an aerosol. The susceptor 12 is preferably completely surrounded by the tobacco material that forms the aerosol-forming substrate 10.

[0153] As shown in the embodiment of FIGS. 1 and 2, the susceptor 12 is completely contained within the rod-shaped article 60, and more preferably, completely contained within the aerosol-forming substrate 10.

[0154] The susceptor 12 is made of an electrically conductive material, preferably a metal, and in some embodiments, a ferromagnetic material.

[0155] According to a preferred embodiment, as shown in Figures 1 and 2, the susceptor 12 has the shape of a strip. Alternatively, it may have the shape of a rod. Its thickness is preferably comprised between 30 micrometers and 60 micrometers. The length of the susceptor is preferably comprised between 5 millimeters and 20 millimeters.

[0156] FIG. 3 shows a portion of a preferred embodiment of the drum 4 of the inspection device 100 according to the first aspect of the present invention.

[0157] For clarity, the inspection apparatus 100 is only partially shown in FIG.

[0158] As will become apparent from the following description, the inspection device 100 is adapted to control the quality of the rod-shaped articles 60, in particular the susceptors 12.

[0159] The quality control provided by the inspection apparatus 100 may involve checking the presence, integrity, or correct position of the susceptor 12 as well as any of the further characteristics of the latter.

[0160] By way of non-limiting example, such characteristics may include one or more of the length of the susceptor, the thickness of the susceptor, the deviation of the susceptor from linear extension, the deviation of the axis of the susceptor from parallelism with the longitudinal axis 61 of the rod-shaped article 60, and the electromagnetic properties of the susceptor.

[0161] Also, quality control may be carried out at any stage of the manufacturing process of the aerosol-generating article, meaning that the rod-shaped article 60 can be checked when the aerosol-forming substrate 10 is joined to the mouthpiece filter element 2, or any other component fixed thereto, or the aerosol-forming substrate 10 itself, including the susceptor 12, can be checked.

[0162] Referring again to Figure 3, the drum 4 comprises a plurality of seats 41, each adapted to receive a rod-shaped article 60. The seats 41 are preferably located on the outer surface 40 of the drum 4. There are preferably about 20 to 60 (preferably about 40) seats 41 on the drum 4.

[0163] In some embodiments, the drum 4 is cylindrical, and preferably the outer surface 40 on which the seat 41 is located corresponds to a lateral surface of the cylinder.

[0164] Of course, seats 41 are preferably sized and shaped to at least partially receive rod-shaped article 60. Both the size and shape of seats 41 are preferably selected to receive rod-shaped article 60. More generally, quality control preferably involves positioning rod-shaped article 60 in one of seats 41.

[0165] Positioning of the rod-shaped article 60 may occur either by using a suitable positioning device (not shown in the drawings) or by transferring the rod-shaped article 60 in any other possible manner, for example from another drum or conveyor.

[0166] In some embodiments, the testing apparatus 100 may be included in a facility for manufacturing aerosol-generating articles, and the rod-shaped articles 60 may be transferred to the testing apparatus 100 from a conveyor element of the facility.

[0167] The drum 4 is preferably a rotating drum having an axis of rotation 67. As a result, the drum 4 is able to transport the rod-shaped article 60 from a first position to a second position, preferably forming an entrance position where it is positioned on a seat and an exit position where it is removed from the seat. The first and second positions (not depicted in FIG. 3) are separated by an angular rotation of the drum.

[0168] In some embodiments, the seats 41 may be oval shaped to define respective seat axes 42. The seat axes 42 and the rotation axes 67 of the seats 41 are preferably parallel to one another. All axes 42 of the multiple seats 41 are preferably parallel to one another.

[0169] The seat 41 is preferably formed on the outer surface 40 of the drum 4. The seat 41 may also be in the form of a recess realised on the outer surface 40 of the drum 4.

[0170] Nevertheless, it is sufficiently clear that the seat 41 may also be defined by other elements on the outer surface of the drum 4, for example fixed thereto and projecting radially therefrom.

[0171] The drum 4 preferably defines a front face 64 and a rear face (not visible). The rear face is axially opposite the front face 64.

[0172] In some embodiments, the seat 41 may extend from the front surface 64 to the rear surface, i.e., the seat may be provided with opposite open ends.

[0173] In this manner, the rod-like article 60 may be received within the seat 41 by approaching the seat laterally, preferably by sliding along the direction defined by the seat axis 42 .

[0174] As shown in the embodiment of Figure 3, the seat 41 may have a length at least equal to the length of the rod-like article 60 to be checked. Longer seats 41 (which allow the rod-like article 60 to slide therein) may also be used.

[0175] In some embodiments, the axis of rotation 67 of the drum 4 is substantially horizontal.

[0176] The seat 41 may be configured so that the rod-shaped article 60 is ejected from the seat 41 when the rod-shaped article 60 reaches a particular angular position along the rotation axis 67 where gravity acts on the rod-shaped article 60 to release the rod-shaped article 60 from the drum 4.

[0177] The inspection device 100 further includes an inductive sensor 5 positioned at least in one of the plurality of seats 41. It will be appreciated that although the embodiment of Figure 3 depicts a single inductive sensor 5 positioned in a particular seat 41, each seat 41 of the drum 4 may include a respective inductive sensor 5.

[0178] Also, according to a further possible embodiment, an inductive sensor 5 may be provided at selected locations 41, for example at a predetermined angular distance.

[0179] The inductive sensor 5 preferably includes a coil 51 defining an interior volume 50 large enough to receive at least the end of a rod-shaped article 60 therein.

[0180] 7 and 8 show a coil 51 according to a preferred embodiment.

[0181] Coil 51 defines a coil axis 70 and preferably has an inner diameter 71 comprised between 10 millimeters and 18 millimeters, more preferably between 12 millimeters and 16 millimeters. Preferably, inner diameter 71 of coil 51 is 14 millimeters.

[0182] Naturally, the above diameters are selected to make the coil 51 wide enough to receive the mouth end 24 or distal end 26 of the rod-shaped article 60 therein, while at the same time avoiding bulky elements for use in the inspection device 100.

[0183] In some embodiments, the length of the coil 51 is adapted to completely accommodate the rod-shaped article 60 therein. Preferably, the length 72 of the coil is comprised between 20 mm and 40 mm, more preferably between 25 mm and 35 mm. The length 72 of the coil 51 is preferably 32 mm.

[0184] In some embodiments, the coil 51 is formed by a pair of parallel wound wires.

[0185] Preferably, the coil 51 has a total number of turns comprised between 26 and 46. More preferably, the number of turns comprises between 30 and 42. Preferably, the number of turns is 32.

[0186] If the coil 51 is formed by a pair of wires, each wire may have half the total number of turns mentioned above.

[0187] The coil 51 is preferably cylindrical in shape and is preferably positioned in the seat such that the coil axis 70 is parallel to the seat axis 42.

[0188] The presence of the susceptor 12 within the rod-shaped article 60 may be sensed by moving the rod-shaped article 60 relative to the coil 51 and considering fluctuations in the feedback signal generated by the interaction between the susceptor 12 and the coil 51.

[0189] To this end, in some embodiments as in FIG. 3, the inspection apparatus 100 comprises a control unit 7 electrically connected to the inductive sensor 5 and adapted to receive a signal from the inductive sensor 5 and to compare the signal with a threshold value in order to detect fluctuations in the signal caused by the presence of the susceptor 12.

[0190] Of course, such fluctuations in the signal may be caused either by moving the coil 51 relative to the rod-shaped article 60, as in the embodiment of Figure 3, or by moving the rod-shaped article 60 relative to the coil 51, as in the embodiment of Figure 4 or Figure 5.

[0191] In general, it will be appreciated that the inductive sensor 5 may generate an alternating magnetic field within the coil 51 that changes when passed by the susceptor 12. More generally, the inductive sensor 5 is configured to generate an alternating magnetic signal in a detection direction that preferably corresponds to the axis 70 of the coil 51.

[0192] The magnetic field generated by the inductive sensor 5 preferably changes when the first end 24, 26 of the rod-shaped article 60, within which the susceptor 12 should be located, is received within the internal volume 50 of the coil 51 of the inductive sensor 5.

[0193] In other words, the magnetic field generated by the passage of the susceptor 12 through the internal volume 50 of the inductive sensor 5 acts against the magnetic field generated by the sensor 5, i.e., by the coil 51. According to Lenz's law, the susceptor 12 acts as a resistor in the coil 51, or more generally in the inductive sensor 5.

[0194] More specifically, when a ferromagnetic material enters a magnetic field, an electromagnetic force is induced in it (Maxwell-Faraday's law), which generates alternating eddy currents. This alternating current generates an induced magnetic field (Maxwell-Ampere's law) that opposes the sensor's magnetic field (Lenz's law).

[0195] The presence or absence of susceptor 12 within rod-shaped article 60 may accordingly be determined in terms of this expected behavior in the magnetic field. If no change occurs when rod-shaped article 60 passes through the alternating magnetic field generated by coil 51, susceptor 12 is likely not present within rod-shaped article 60.

[0196] In contrast, the change may be determined by calculating the impedance of the rod-like article 60, which changes as the susceptor 12 passes through the interior volume 50 of the coil 51, as previously explained.

[0197] According to a preferred embodiment, the feedback signal generated as the susceptor 12 passes through the interior volume 50 can be used to determine other characteristics of the susceptor 12 .

[0198] Referring to FIG. 6, a possible use of the feedback signal may be for the purpose of determining the length of the susceptor 12 .

[0199] FIG. 6 shows how the equivalent resistance of the system “coil and susceptor” varies according to the relative position of the susceptor 12 within the internal volume 50 .

[0200] Initially, when no rod-shaped article 60 is present in the interior volume 50, the feedback signal output by the inductive sensor 5 does not change.

[0201] As the rod-like article 60 enters the interior volume 50, a fluctuation in the feedback signal occurs.

[0202] The feedback signal reaches a minimum level when the entire susceptor 12 is completely inside the inner volume 50 and begins to decrease as soon as the end of the susceptor 12 exits the coil 51 .

[0203] By comparing this signal with the position of the rod-like article 60 within the interior volume 50, the length of the susceptor 12 can be determined.

[0204] The length of the susceptor 12 is preferably estimated according to the peak of the measured equivalent resistance, which is determined after appropriate calibration.

[0205] Alternatively, the impedance parameter function exhibits a maximum rather than a minimum when the susceptor is fully inserted into the coil.

[0206] In such an embodiment, the coil 51, or more generally the internal volume 50 of the inductive sensor 5, is longer than the expected length of the susceptor 12, also according to the coil characteristics mentioned above.

[0207] The length of the coil 51 is preferably selected to be at least 10 millimeters per side longer than the expected length of the susceptor 12 to avoid distortion of the magnetic field at the ends of the coil.

[0208] According to a preferred embodiment, the control unit 7 is configured to determine whether the length of the susceptor 12 corresponds to an expected value by checking the variation of the feedback signal with the position of the rod-shaped article 60 in the internal volume 50.

[0209] Naturally, the control unit 7 may also be adapted to calculate the length of the susceptor 12 located within the rod-shaped article 60 according to different methods, for example taking into account other specific behaviors of the inductive sensor 5 generally during the interaction of the rod-shaped article 1 with the internal volume 50.

[0210] More generally, the equivalent resistance of the feedback signal may indicate the nature or consistency of the shape or composition of the susceptor 12. As a result, further characteristics of the susceptor 12 may be determined by the inspection apparatus 100 of the present invention.

[0211] To introduce the rod-shaped article 60 into the coil 51, in the inspection device 100 of FIG. 3, the coil 51 is divided into two half coils 65 and 66. The first half coil 66 is positioned below the outer surface 40 of the drum 4, while the second half coil 66 is positioned above the outer surface 40 of the drum 4. The two half coils 65, 66 can be moved from a first operating position shown in FIG. 13, where the two half coils form the coil 51. In this first operating position, the measurements described above with the inductive sensor, for example, those shown in FIG. 6, can be performed. In the second operating position depicted in FIGS. 3 and 13, the second half coil 65 is moved along the coil axis 70 and spaced apart from the first half coil, allowing the rod-shaped article 60 to be positioned within the seat 41. The movement is performed by an actuator 6 connected to a control unit 7.

[0212] In operation of the inspection device 100 of Figures 3, 13, and 14, a rod-shaped article 60 is inserted into the seat 41. When the rod-shaped article is positioned in the seat, the first half coil 66 and the second half coil 65 are in the second operating position, i.e., the two half coils 65, 66 are separated from each other, as in Figures 3 and 14. Once the rod-shaped article 60 is in the seat, the first half coil 66 and the second half coil 65 are moved to the first operating position of Figure 13 so that measurements can be taken using the inductive sensor 5. The relative movement of the first and second half coils is as follows: the first half coil 66 is positioned below the outer surface 40 and is fixed relative to it, while the second half coil 65 is translated back and forth from the first operating position of Figure 14 to the second operating position of Figures 3 and 14, and vice versa. The shifting of the second half coil 65 from the first operating position to the second operating position, and vice versa, is achieved by a piston 69 connected to the actuator 6. The piston 69 is attached to the second half coil and moves the second half coil linearly towards and away from the first half coil, as shown by arrow 68 in Figure 3.

[0213] In a different embodiment of the present invention depicted in FIGS. 4 and 5, instead of the movement of the coil relative to the rod-shaped article as in the embodiments of FIGS. 3, 13, and 14, the movement of the rod-shaped article 60 relative to the coil 51 is performed. In the inspection apparatus 200, the same reference numerals as used in the inspection apparatus 100 are used to identify the same elements. In the inspection apparatus 200, the inductive sensor 5 includes a coil 51, which in this case is attached to the outer surface 40 of the drum 4. The coil 51 (better seen in FIGS. 7 and 8) is located, for example, at one end of the seat 41. The inspection apparatus 200 includes a compressed air system 8, 9 including a compressed air generator 9 and a gun 8 for discharging a compressed air flow. The gun may discharge a compressed air flow in a direction substantially parallel to the seat axis 42, and therefore parallel to the longitudinal axis of the rod-shaped article 60. The gun may be located on one side of the drum 4 and may be stationary, i.e., not rotate with the drum. In this way, a single compressed air system may be used for all seats 41. During rotation, as the rod-shaped article passes in front of the gun 8, a stream of compressed air is discharged, which pushes the rod-shaped article 60 into the coil 51, and the inductive sensor 5 can be used to make the measurements mentioned above. This is shown in FIG. 5, which depicts a series of "screen shots" taken at successive time intervals. At the left edge of the figure, the rod-shaped article 60 is inserted into the seat 41. In a subsequent rotation, the seat with the rod-shaped article 60 passes in front of the gun 8, and a stream of compressed air is discharged by the gun 8 along the direction 83. The rod-shaped article 60 is then pushed into the coil 51 (see the snapshots below from left to right in the figure (up to the dashed line 64)).

[0214] A dashed line 84 separates Figure 5 in two. The second part of Figure 5 to the right of dashed line 84 is taken some time interval later than the part to the left (see below for details).

[0215] The inspection apparatus 100, 200 of the present invention may also comprise a rejection device (schematically depicted as a rectangle 82 in the right part of FIG. 5 ) adapted to reject rod-shaped articles 60 that do not have a susceptor 12 therein or that have a susceptor 12 that does not conform to expected characteristics. As previously explained, the rod-shaped articles 60 may advantageously be rejected based on a signal emitted by the inductive sensor 5, according to a calculation or determination made by the control unit 7. As shown in the right part of FIG. 5 , for example, the effect of the rejection device 82 is to keep defective rod-shaped articles 60 in drum 4 while valid rod-shaped articles 60 are transferred to other drums (not shown) for continuing processing.

[0216] The rod-shaped article 600 may also include a first susceptor 12 and a second susceptor 121 as depicted in Figure 9. The rod-shaped article 600 substantially includes two rod-shaped articles 60 according to the embodiment of Figures 1 and 2.

[0217] When the rod-shaped article 600 includes two or more susceptors, it is preferable to provide an inspection apparatus according to the third embodiment as the inspection apparatus 300 of FIG.

[0218] The inspection apparatus 300 includes two or more checking drums 4, at least a first drum and a second drum, each of which includes a coil 51. The first drum or the second drum is identical to the drum 4, which can be according to either the first embodiment of Figures 3 and 13-14 or the second embodiment of Figures 4 or 5. However, it is preferred that the drums are of the same type, i.e. according to either the first embodiment of the inspection apparatus 100 or the second embodiment of the inspection apparatus 200.

[0219] The first drum 4 is adapted to check the first susceptor 12 of the rod-shaped article 600, while the second drum 4 is adapted to check the second susceptor 121 of the rod-shaped article 600. For example, if the first drum and the second drum are according to the second embodiment of Figures 4 and 5, in the first drum, the compressed air system is located on the first side of the first drum, and in the second drum, the compressed air system is located on the second side of the second drum.

[0220] 11 and 12, after the first susceptor 12 is inspected, the rod-shaped article 600 is transferred from the first drum to the second drum. The first drum and the second drum are substantially in contact with each other. The gap between the first drum and the second drum is such that the rod-shaped article 600 can be inserted therebetween. The transfer takes place between the seat of the first drum and the seat of the second drum.

[0221] In Figure 11, the transfer between two drums 4 according to the first embodiment of Figures 3, 13 and 14 is shown. In Figure 12, the transfer between two drums 4 according to the second embodiment of Figures 4 and 5 is shown.

[0222] For purposes of this specification and the appended claims, unless otherwise indicated, all numbers expressing amounts, quantities, percentages, and the like should be understood in all instances to be modified by the term "about." Also, all ranges include the disclosed maximum and minimum points, and include any intermediate ranges therein, which may or may not be specifically recited herein. Accordingly, in this context, the number A is understood as A ± 10 percent. Within this context, the number A may be considered to include a numerical value that is within the common standard error for measurement of the property represented by the number A. In some cases, as used in the appended claims, the number A may deviate by the percentages recited above, provided that the amount by which A deviates does not materially affect the basic and novel property(ies) of the claimed invention. Also, all ranges include the disclosed maximum and minimum points, and include any intermediate ranges therein, which may or may not be specifically recited herein.

Claims

1. 1. An inspection apparatus for quality control of rod-shaped articles, said apparatus comprising: a drum defining an outer surface and including a plurality of seats, each seat of the plurality adapted to receive a rod-shaped article; an inductive sensor located at one of the plurality of locations, the inductive sensor including a coil defining an interior volume large enough to receive an end of the rod-shaped article therein, the inductive sensor adapted to sense a characteristic of a susceptor within the rod-shaped article; the coil includes a first half-coil and a second half-coil, the first half-coil and the second half-coil being movable from a first operating position in which the first half-coil and the second half-coil are in contact with each other to form the coil through which a current can flow to a second operating position in which the first half-coil and the second half-coil are separated from each other, and vice versa; an inductive sensor, the first half-coil located below the outer surface of the drum and the second half-coil located above the outer surface of the drum; an actuator adapted to move the first half-coil and the second half-coil from the first operating position to the second operating position and vice versa.

2. 2. The inspection device of claim 1, further comprising a control unit adapted to command the actuator to move the first half-coil or the second half-coil from the second operating position to the first operating position when a rod-shaped article is on the seat.

3. 3. The inspection device of claim 1, wherein the seat includes a receiving surface, a portion of the outer surface of the drum, and the first half coil is positioned below the receiving surface of the seat.

4. 1. An inspection apparatus for quality control of rod-shaped articles, said apparatus comprising: a drum including a plurality of seats, each seat of the plurality adapted to receive a rod-shaped article; an inductive sensor located at one of the plurality of locations, the inductive sensor including a coil defining an interior volume large enough to receive an end of the rod-shaped article therein, the inductive sensor adapted to sense a characteristic of a susceptor within the rod-shaped article; a compressed air system aligned with the seats of the plurality; an actuator adapted to activate the compressed air system to blow air and push the rod-shaped article inside the coil when the rod-shaped article is positioned within the seat.

5. 5. The inspection apparatus of claim 1, wherein the drum has an axis of rotation, and each seat of the plurality defines a longitudinal axis, the longitudinal axis and the axis of rotation being parallel to one another.

6. 6. The inspection device according to claim 1, wherein the length of the coil is between 20 mm and 40 mm.

7. 7. The inspection device according to one or more of the preceding claims, comprising a control unit electrically connected to the inductive sensor, the control unit being adapted to receive a signal from the inductive sensor and to compare the signal with a threshold value.

8. 8. The inspection device of claim 7, wherein the control unit is adapted to calculate a length of a susceptor located within the rod-shaped article.

9. An inspection device according to one or more of the preceding claims, comprising a rejection device adapted to reject rod-shaped articles on the basis of the signal emitted by the inductive sensor.

10. An inspection device according to one or more of the preceding claims, wherein the drum comprises a plurality of inductive sensors, one sensor for each seat of the plurality of seats.

11. 11. An inspection device according to one or more of the preceding claims, wherein the seat defines a seat axis, the coil defines a coil axis, and the coil axis and the seat axis are parallel to each other.

12. An inspection device, a first drum defining a first outer surface and including a first plurality of seats, each seat of the first plurality adapted to receive a rod-shaped article; a first inductive sensor positioned at one of the first plurality of loci, the first inductive sensor including a first coil defining an interior volume large enough to receive a first end of the rod-shaped article therein, the first inductive sensor adapted to sense a characteristic of a first susceptor in the rod-shaped article; the first coil includes a first half-coil and a second half-coil, the first half-coil and the second half-coil being movable from a first operating position in which the first half-coil and the second half-coil are in contact with each other to form the first coil through which a current can flow to a second operating position in which the first half-coil and the second half-coil are separated from each other, and vice versa; the first half-coil is located below the first outer surface of the first drum and the second half-coil is located above the first outer surface of the first drum; a first actuator adapted to move the first half-coil and the second half-coil of the first coil from the first operating position to the second operating position and vice versa within the first drum; a second drum defining a second outer surface and including a second plurality of seats, each seat of the second plurality adapted to receive a rod-shaped article; a second inductive sensor located at the second plurality of locations, the second inductive sensor including a second coil defining an interior volume large enough to receive a second end of the rod-shaped article therein, the second inductive sensor adapted to sense a property of a second susceptor in the rod-shaped article; and the second coil includes a first half-coil and a second half-coil, the first half-coil and the second half-coil being movable from a first operating position in which the first half-coil and the second half-coil are in contact with each other to form the second coil through which a current can flow to a second operating position in which the first half-coil and the second half-coil are separated from each other, and vice versa; Preferably, the first half-coil of the second coil is located below the second outer surface and the second half-coil of the second coil is located above the second outer surface; a second actuator adapted to move the first half-coil and the second half-coil of the second coil from the first operating position to the second operating position and vice versa within the second drum; an inspection apparatus wherein the first drum and the second drum are substantially tangent to allow transfer of the rod-shaped article from the first drum to the second drum;

13. An inspection device, a first drum including a first plurality of seats, each seat of the first plurality adapted to receive a rod-shaped article; a first inductive sensor positioned at one of the first plurality of loci, the first inductive sensor including a first coil defining an interior volume large enough to receive a first end of the rod-shaped article therein, the first inductive sensor adapted to sense a characteristic of a first susceptor in the rod-shaped article; a first compressed air system aligned with the seats of the first plurality; a first actuator adapted to activate the first compressed air system to blow air and push the rod-shaped article into the first coil when the rod-shaped article is located within the seat of the first plurality of seats; a second drum including a second plurality of seats, each seat of the second plurality adapted to receive a rod-shaped article; a second inductive sensor positioned at one of the second plurality of locations, the second inductive sensor including a second coil defining an interior volume large enough to receive a second end of the rod-shaped article therein, the second inductive sensor adapted to sense a characteristic of a second susceptor in the rod-shaped article; and a second compressed air system aligned with the seats of the second plurality; a second actuator adapted to activate the second compressed air system to blow air when the rod-shaped article is located within the seats of the second plurality of seats, thereby forcing the rod-shaped article inside the second coil of the second drum; an inspection apparatus wherein the first drum and the second drum are substantially tangent to allow transfer of the rod-shaped article from the first drum to the second drum;

14. 1. A method for inspecting a rod-shaped article, comprising: When dependent on claim 1, providing an inspection device according to one or more of claims 1 to 3 or claims 5 to 12; positioning the rod-shaped article within the seat of the drum, with the first half-coil and the second half-coil in the second operating position; moving the first half-coil and the second half-coil in the first operating position; and sensing a property of the susceptor.

15. 1. A method for inspecting a rod-shaped article, comprising: When dependent on claim 2, providing an inspection device according to claim 2 or one or more of claims 5 to 12; positioning the rod-shaped article within the seat of the drum; forcing the rod-shaped article into the coil with an airflow; and sensing a characteristic of the susceptor.

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