Testing apparatus and method for testing heating elements in aerosol-generating articles - Patents.com

Abstract

The present invention relates to a non-destructive testing apparatus and method for testing heating elements in aerosol-generating articles. The testing apparatus comprises a control module having a passageway for an aerosol-generating article to pass through the control module. The control module further comprises a control circuit and a measurement device. The control circuit comprises an excitation coil configured to generate an alternating magnetic field in the passageway of the control module. The measurement device is configured to determine a value related to a load applied to the control circuit in response to a physical characteristic of the heating element as the heating element passes through the passageway into the control module. The control module is further configured to determine whether the determined value of the tested heating element corresponds to a predetermined value for a predetermined heating element.

Description

[Technical field]

[0001] The present invention relates to a non-destructive testing apparatus and method for testing a heating element in an article comprising said heating element. [Background technology]

[0002] Articles comprising an aerosol-forming substrate and a heating element for heating the substrate to generate an aerosol are generally known from the prior art. In particular, in induction-heated articles comprising a susceptor as the heating element, the material parameters of the susceptor need to be within very specific ranges for optimized performance of the heating element. However, testing the article under real conditions and therefore the performance of the heating element during heating is time-consuming and renders the article unusable.

[0003] Thus, there is a need for a testing apparatus and method that allows for non-destructive and rapid testing of heating elements in aerosol-generating articles that include heating elements. Summary of the Invention

[0004] According to the present invention, there is provided a non-destructive testing apparatus for testing a heating element in an aerosol-generating article. The testing apparatus comprises a control module having a passageway for the aerosol-generating article to pass through the passageway to the control module. The control module further comprises a control circuit and a measurement device. The control circuit comprises an excitation coil configured to generate an alternating magnetic field in the passageway of the control module, and the measurement device is configured to determine a value related to a load applied to the control circuit in response to a physical characteristic of the heating element as the heating element passes through the passageway to the control module. The control module is further configured to determine whether the determined value of the tested heating element corresponds to a predetermined value for a predetermined heating element.

[0005] The testing apparatus allows the article to be tested while the article passes through the testing apparatus in a passageway within the testing apparatus. An excitation coil within the control module may be activated and a response of the article may be measured with a measurement device in the control module. The response is characteristic of the material parameters of the heating element, in particular its apparent resistance.

[0006] This test allows for very rapid testing of heating elements whilst still allowing for further use of the tested article.

[0007] Preferably, the value representing the physical property of the heating element is a permeability, an apparent electrical resistance, or an apparent electrical conductance, and the predetermined value of the heating element is a predetermined permeability, a predetermined electrical resistance, or an electrical conductance. Most preferably, the value representing the physical property of the heating element is an apparent electrical resistance, and the predetermined value is a predetermined electrical resistance.

[0008] The determined value is preferably a value indicative of the apparent electrical resistance of the heating element.

[0009] The detected or measured resistance typically corresponds to the resistance of the system, specifically the resistance of the excitation coil and the resistance of the heating element. From the measurement, the known resistance of the excitation coil can be subtracted to obtain the resistance of the heating element.

[0010] The measurement device may comprise a current measurement device for determining a DC current drawn by the control circuit from a DC power source of the device, the measurement device being configured to determine an electrical resistance value of the control circuit from a ratio of the determined DC current to a DC voltage applied to the control circuit.

[0011] In a test fixture, the excitation coil may be part of the LRC circuit of the measurement device.

[0012] The control circuit of the control module is configured to power the excitation coil. In particular, the control circuit is configured to provide power pulses for powering the excitation coil. The control circuit is preferably configured to operate the excitation coil at low power. This prevents any possible heating of the heating element, in particular heating due to eddy currents in the resistive material of the heating element. The control circuit is preferably configured to apply a DC voltage to the control circuit in the range of 0.5V to 3V, preferably 1V.

[0013] With DC voltages in this power range, good test results are obtained, thus providing acceptable measurements, and the heating element is not heated. In particular, good test results have been achieved with LRC parameters having a magnetic inductance L in the range of about 0.1 microhenry to 0.15 microhenry, e.g., 0.12 microhenry, and an excitation coil (background) electrical resistance R in the range of about 38 milliohms to 43 milliohms, e.g., 40 milliohms to 41 milliohms.

[0014] The control module is preferably configured to output acceptance of the aerosol-forming article when the determined value of the tested heating element corresponds to the predetermined value of the predetermined heating element. The control module is preferably configured to output rejection of the aerosol-generating article when the determined value of the tested heating element does not correspond to the predetermined value of the predetermined heating element.

[0015] "Corresponding" is defined herein as corresponding to the exact value of a given value, as well as to a value within a given threshold of ±20 percent of the given value, and more preferably to a value within a given threshold of ±10 percent of the given value.

[0016] The excitation coil is preferably disposed within the control module and arranged to surround the passageway such that an article to be tested may be guided through the center of the excitation coil, the article preferably passing through the excitation coil along a central longitudinal axis of the excitation coil.

[0017] The passageway in the control module is a path in the control module along which the aerosol-generating article may be guided, the article being made to pass the excitation coil and measuring device of the control module along the path. The path may be opened and closed along the path through the control module. The passageway in the control module is preferably a through hole through the control module.

[0018] The passageways have open ends to allow objects to pass through the control module without issue. The diameter of the passageways, particularly the diameter of the through-holes, is preferably about 10 percent to 50 percent larger than the diameter of the objects that will be tested and passed through the passageways.

[0019] Preferably, the passage partially or completely surrounds an article passing through the passage.

[0020] Preferably, the passage has a tubular shape.

[0021] Preferably, the passageway is formed as a tube within the control module.

[0022] Preferably, the passage has a circular or elliptical cross section.

[0023] The testing apparatus may further comprise a guide element for guiding the aerosol-generating article into the passageway of the control module. The guide element may comprise a conveyor for transporting the aerosol-generating article to, and preferably through, the control module. Alternatively, or additionally, the guide element may comprise a slide for guiding the aerosol-generating article on the slide into the passageway of the control module. It is preferred that a slide is provided when the article is guided into the control module only by gravity.

[0024] The guide element may comprise a converging guide that converges with respect to the passage opening. Such a converging guide may support accurate guidance of a single article to the passage opening, in particular to the centre of the passage opening.

[0025] The testing device may further comprise a reservoir for holding the aerosol-generating articles, the reservoir being disposed upstream of the control module. By providing a reservoir, multiple articles may be subsequently and rapidly delivered to the testing device, thus enabling a rapid testing sequence of articles. The reservoir may, for example, comprise articles of the same batch of articles to be tested. With a reservoir, the testing device may be operated continuously or automatically, so that personnel may only be required to fill the reservoir.

[0026] The testing device may be a stand-alone device for testing an article comprising a heating element, for example an article that is a plurality of segments of a final consumable product, an article that is a segment of a final consumable product, or an article that is a final consumable product, for example a heat stick.

[0027] The testing device may be integrated into the manufacturing process of an aerosol-generating article, e.g., the article as part of a final consumable product such as a heat stick, or into the manufacturing process of a final consumable product such as a heat stick, etc. The testing device is then used to test the final product or semi-finished product, where the testing is integrated into the manufacturing process.

[0028] For example, the article may be a rod-shaped plug of an aerosol-forming substrate, such as a tobacco plug provided with a heating element. The plug may also be the final plug of a heat stick to be used in combination with an electronic aerosol generator, preferably an inductively heated aerosol generator.

[0029] In some preferred embodiments, the testing device is disposed between article production components, which may be, for example, one of a rod forming device and a cutting device disposed upstream of the testing device, and which may be, for example, one of a cutting device, an article storage, and an article packaging device disposed downstream of the testing device.

[0030] The present invention also relates to a non-destructive testing method for testing a heating element in an aerosol-generating article, the method comprising providing an aerosol-generating article comprising a heating element, passing the aerosol-generating article through an alternating magnetic field of a control circuit without heating the heating element, determining a value related to the load due to the heating element applied to the control circuit in response to a physical characteristic of the heating element passing through the alternating field of the control circuit, and comparing the determined value for the tested heating element with a predetermined value for a predetermined heating element.

[0031] The method may further include accepting the aerosol-generating article if the difference between the determined value of the tested heating element and the predetermined value is within a predetermined threshold, or rejecting the aerosol-generating article if the difference between the determined value of the tested heating element and the predetermined value exceeds a predetermined threshold.

[0032] Preferably, the method includes determining a value indicative of the apparent electrical resistance of the heating element.

[0033] In some embodiments, the method includes measuring a DC current drawn by the control circuit from a DC power source and determining an apparent electrical resistance value of the control circuit from a ratio of the determined DC current to a DC voltage applied to the control circuit.

[0034] To perform the measurement, the method includes providing a power pulse from the control module to an excitation coil.

[0035] Preferably, the method includes applying a DC voltage between 0.5V and 3V to the control circuit.

[0036] Testing of aerosol-generating articles may be performed while the article is stationary during measurements. In these embodiments, the article is moved to the control unit of the testing apparatus, guided into an aisle, stopped therein to perform measurements, and then moved out of the aisle. Because the article is moving but the test is stationary, the accuracy of the test results is improved while allowing for high speed testing of multiple articles simultaneously.

[0037] The articles are preferably moving through the passage while being tested. Testing moving articles, preferably continuously moving articles, allows for very rapid testing of a large number of articles. High speed testing may not be as accurate as slow speed testing, but the more defective the heating elements are, the more accurate the high speed testing becomes. Thus, high speed testing is well suited to identifying very "bad" heating elements.

[0038] In the method according to the invention, the aerosol-generating article, when tested, may be passed through an alternating magnetic field at a speed between 0 m / s and 40 m / s.

[0039] Preferably, the aerosol-generating article, when tested, passes through an alternating magnetic field at a speed of between 10 m / s and 30 m / s.

[0040] The aerosol-generating article preferably passes through the centre of the excitation coil.

[0041] A concentric arrangement of the article and excitation coil may reduce irregularities in the excitation of the material of the heating element when it is temporarily disposed within or passing through the excitation coil. It is preferred that the heating element and excitation coil have a symmetrical arrangement when the article is passing through the excitation coil.

[0042] The method preferably includes guiding the aerosol-generating article to the centre of the excitation coil, whereby the article may enter the excitation coil centrally and then pass the control unit along the longitudinal axis of the excitation coil. The aerosol-generating article may thereby be conveyed through the alternating magnetic field by a conveying means, for example by a conveyor such as a conveyor belt. Alternatively, the aerosol-generating article falls through the alternating magnetic field by gravity.

[0043] In some embodiments, the method may further comprise providing a reservoir comprising an aerosol-generating article comprising a heating element, and guiding the aerosol-generating article from the reservoir into the alternating magnetic field.

[0044] The aerosol-generating article is preferably rod-shaped, more preferably a rod-shaped aerosol-generating substrate equipped with a heating element.

[0045] The aerosol-generating article may have a final length of a consumable tobacco plug for use in an aerosol generating device. The aerosol-generating article may have a plurality of final lengths of a consumable tobacco plug for use in an aerosol generating device. The method may therefore comprise a step of adapting the predetermined value of the predetermined heating element according to the length of the predetermined heating element. Depending on the amount of conductive material in the article, which represents the heating element and is present in the excitation coil, the load of the control circuit changes and thus the response of the measuring device. Therefore, the predetermined value is preferably adapted to the expected predetermined value of the heating element being tested.

[0046] Preferably, the heating element is an inductively heated heating element and includes at least one susceptor material. More preferably, the heating element is a multi-layer susceptor arrangement.

[0047] The heating elements, especially the multi-layer susceptor elements, may have different shapes, for example pin-shaped, rod-shaped or strip-shaped. Preferably, the heating elements are elongated heating elements.

[0048] The multi-layer susceptor arrangement is preferably an elongated, strip-shaped multi-layer susceptor arrangement, wherein a first layer of a first susceptor material of the multi-layer susceptor arrangement and a second layer of a second susceptor material of the multi-layer susceptor arrangement are in intimate physical contact with each other, and the second susceptor material preferably comprises a Curie temperature of less than 500 degrees Celsius.

[0049] The first susceptor material may preferably have no Curie temperature or a Curie temperature greater than 500 degrees Celsius.

[0050] The first susceptor material is preferably used primarily to heat the susceptor when the susceptor is placed in a fluctuating 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 first susceptor material preferably comprises or consists of a metal, such as ferritic iron, or stainless steel, specifically grade 410, grade 420, or grade 430 stainless steel.

[0051] The second susceptor material is preferably used primarily to indicate when the susceptor has reached a particular temperature, which is 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 assembly during operation. Therefore, the Curie temperature of the second susceptor material should be below the ignition point of the aerosol-forming substrate. Close proximity of the first and second susceptor materials can be advantageous in providing precise temperature control.

[0052] The first susceptor material is preferably a magnetic material having a Curie temperature above 500 degrees Celsius. From the standpoint of heating efficiency, it is desirable for the Curie temperature of the first susceptor to exceed any maximum temperature to which the susceptor assembly can be heated. The Curie temperature of the second susceptor material may be selected to be preferably lower than 400 degrees Celsius, preferably lower than 380 degrees Celsius, or lower than 360 degrees Celsius. The second susceptor material is preferably a magnetic material selected to have a Curie temperature that is substantially the same as the desired maximum heating temperature. The Curie temperature of the second susceptor material may be, for example, within the range of 200 degrees Celsius to 400 degrees Celsius, or 250 degrees Celsius to 360 degrees Celsius.

[0053] Thus, when heated, the first and second susceptor materials have the same temperature. When the susceptor arrangement is housed in an article, the first susceptor material, which may be optimized for heating the aerosol-forming substrate, may have a first Curie temperature that is higher than a predetermined maximum heating temperature. When the susceptor reaches the second Curie temperature, the magnetic property of the second susceptor material changes. At the second Curie temperature, the second susceptor material reversibly changes from a ferromagnetic phase to a paramagnetic phase. During induction heating, this phase change of the second susceptor material may be detected without physical contact with the second susceptor material. Detection of the phase change may allow control over the heating of the aerosol-forming substrate in the actual use of the susceptor arrangement. For example, induction heating may be automatically stopped when a phase change associated with the second Curie temperature is detected. In this way, overheating of the aerosol-forming substrate can be avoided even if the first susceptor material, which is primarily responsible for heating the aerosol-forming substrate, does not have a Curie temperature, i.e. a first Curie temperature higher than the desired maximum heating temperature. After the induction heating is stopped, the susceptor is cooled until it reaches a temperature lower than the second Curie temperature. At this point, the second susceptor material regains its ferromagnetic properties. This phase change can be detected without contacting the second susceptor material, and thus induction heating can be reactivated. In this way, the induction heating of the susceptor arrangement and the aerosol-forming substrate surrounding the susceptor assembly can be controlled by repeatedly starting and stopping the induction heating device. This temperature control is achieved by contactless means. The intimate contact between the first susceptor material and the second susceptor material may be made by any suitable means. For example, the second susceptor material may be plated, deposited, coated, clad, or welded onto the first susceptor material. Preferred methods include electroplating, galvanizing, and cladding. The second susceptor material is preferably present as a dense layer. A dense layer has a higher magnetic permeability than a porous layer, making it easier to detect minute changes in the Curie temperature. If the first susceptor material is optimized for heating the substrate, it may be preferred that the amount of the second susceptor material is no greater than is required to provide a detectable second Curie point.

[0054] Suitable materials for the second susceptor material may include nickel and certain nickel alloys.

[0055] It has been found that the specific material selection of the second susceptor material can reduce undesirable effects in the susceptor arrangements that arise during their manufacture due to the effect that limited free movement between the various susceptor materials, especially between the various layers, has on magnetic shrinkage that is difficult to control during mass production of such susceptor arrangements. In particular, these undesirable effects may vary across different locations of the precursor laminate material from which the susceptor arrangements are ultimately made. As a result, the magnetic properties may vary between different susceptor arrangements, even when made of the same precursor material.

[0056] Therefore, the second susceptor material preferably comprises or consists of a Ni-Fe alloy comprising 75 weight percent to 85 weight percent Ni and 10 weight percent to 25 weight percent Fe. More specifically, the Ni-Fe alloy may comprise 79 weight percent to 82 weight percent Ni and 13 weight percent to 15 weight percent Fe. It has been found that Ni-Fe alloys comprising Ni and Fe within the above ranges exhibit only weak or no magnetostriction. As a result, the second susceptor material of the second layer does not change or at least only decreases in its magnetic properties after its processing and throughout the temperature range of its operation. This consequently allows mass production of multi-layer susceptor arrangements having a second magnetic layer that does not change or only changes very little in its magnetic properties after processing and during subsequent operation.

[0057] As used herein, the term "weight percent" or "weight percent" refers to the mass fraction of an element in the alloy, which is the ratio of the mass of the respective element to the total mass of a sample of the alloy.

[0058] In addition to the main constituents, the remainder of the Ni-Fe-alloy may contain one or more of the following elements: Co, Cr, Cu, Mn, Mo, Nb, Si, Ti and V.

[0059] As used herein, the symbol Ni represents the chemical element nickel, the symbol Fe represents the chemical element iron, the symbol Co represents the chemical element cobalt, the symbol Cr represents the chemical element chromium, the symbol Cu represents the chemical element copper, the symbol Mn represents the chemical element manganese, the symbol Mo represents the chemical element molybdenum, the symbol Nb represents the chemical element niobium, the symbol Si represents the chemical element silicon, the symbol Ti represents the chemical element titanium, and the symbol V represents the chemical element vanadium.

[0060] The first layer may have a layer thickness in the range of 20 micrometers to 60 micrometers.

[0061] The second layer may have a layer thickness in the range of 4 micrometers to 20 micrometers.

[0062] The second material may be intimately connected to the first material. As used herein, the term "intimately connected" refers to a mechanical connection between two susceptor materials in a susceptor arrangement, in particular between susceptor layers, such that mechanical forces may be transmitted between the two materials in a direction parallel to the layer structure. The connection may be a layered, two-dimensional, area connection, or full area connection, i.e. a connection on both sides of the opposing surfaces of each of the two layers. The connection may be a direct connection. In particular, the two materials that are intimately connected to each other may be in direct contact with each other. Alternatively, the connection may be an indirect connection. In particular, the two materials may be indirectly connected via at least one intermediate material. The second layer is disposed on the first layer and is intimately connected to the first layer, in particular preferably directly connected to the first layer.

[0063] In some embodiments, the multi-layer susceptor arrangement comprises a third layer intimately connected to the second layer, the third layer comprising a third susceptor material, in this context the term "intimately connected" is used in the same manner as defined above with respect to the first and second materials.

[0064] Preferably, the third susceptor material is a protective material configured to do at least one of the following: prevent the aerosol-forming substrate from sticking to the surface of the susceptor arrangement; prevent material diffusion (e.g., metal migration) from the susceptor material into the aerosol-forming substrate; prevent or reduce thermal bending due to differences in thermal expansion between the materials of the susceptor arrangement; or protect other materials, particularly the second material, from any corrosive effects.

[0065] The latter is particularly important when the susceptor arrangement is embedded in the aerosol-forming substrate of the aerosol-generating article, i.e., when the susceptor arrangement is in direct physical contact with the aerosol-forming substrate. For this reason, the third susceptor material preferably comprises or consists of a corrosion-resistant material. Advantageously, the corrosion-resistant material improves the aging properties of those portions of the outer surface of the second susceptor material that are not corrosion-resistant that are covered by the third susceptor material and therefore are not directly exposed to the environment.

[0066] The term "third layer" as used herein refers to a layer different from and in addition to the first and second layers. Specifically, any possible oxide layer on the surface of the first or second layer resulting from oxidation of the first or second susceptor material should not be considered a third layer (specifically, a third layer including or consisting of a corrosion-resistant material).

[0067] Due to this, the multi-layer susceptor arrangement comprises at least two layers having the same thermal expansion coefficient, which results in reduced deformation of the susceptor arrangement throughout the operating temperature range, especially when the susceptor arrangement comprises only a first layer, a second layer and a third layer, and when the second layer is sandwiched symmetrically between the first layer and the third layer.

[0068] Thus, the third susceptor material may comprise a metal, such as ferritic iron, or stainless steel, such as a ferritic stainless steel, in particular a 400 series stainless steel (such as grade 410 stainless steel, or grade 420 stainless steel, or grade 430 stainless steel, or a similar grade stainless steel). Alternatively, the third susceptor material may comprise or be a suitable non-magnetic material, in particular a paramagnetic conductive material (such as aluminum (Al)). Similarly, the third material may comprise or be a non-conductive ferrimagnetic material, such as a non-conductive ferrimagnetic ceramic.

[0069] It is also possible that the third material comprises or consists of austenitic stainless steel. Advantageously, austenitic stainless steel, due to its paramagnetic properties and high electrical resistance, slightly shields the second layer from the magnetic field applied to the first and second susceptor materials. By way of example, the third layer may comprise or consist of X5CrNi18-10 (designation according to EN (European Standards), material number 1.4301, also known as V2A steel) or X2CrNiMo17-12-2 (designation according to EN (European Standards), material number 1.4571 or 1.4404, also known as V4A steel). In particular, the third layer may comprise or consist of one of 301 stainless steel, 304 stainless steel, 304L stainless steel, 316 stainless steel, or 316L stainless steel (designation according to SAE steel grades [Society of Automotive Engineers]).

[0070] When present, the third material may be a third susceptor layer having a third layer thickness in the range of 2 micrometers to 6 micrometers, specifically 3 micrometers to 5 micrometers, preferably 3 micrometers to 4 micrometers.

[0071] The layer thickness of the third layer may be in the range of 0.05 to 1.5 times, particularly 0.1 to 1.25 times, or 0.95 to 1.05 times, particularly 1 times, the layer thickness of the first layer.

[0072] In the case of a symmetrical or nearly symmetrical layer configuration, the first layer as well as the third layer may have a thickness in the range of 2 micrometers to 20 micrometers, specifically 3 micrometers to 10 micrometers, preferably 3 micrometers to 6 micrometers.

[0073] The second layer may then have a thickness in the range of 5 micrometers to 50 micrometers, specifically 10 micrometers to 40 micrometers, preferably 20 micrometers to 40 micrometers.

[0074] Advantages and features of the invention described with respect to the test apparatus or with respect to the test method are applicable vice versa. EXAMPLES

[0075] The present invention is defined in the claims. However, below is provided a non-exhaustive list of non-limiting examples. Any one or more of the features of these examples may be combined with any one or more features of any other example, embodiment, or aspect described herein.

[0076] Example 1: 1. A non-destructive testing apparatus for testing a heating element within an aerosol-generating article, comprising: a control module having a passageway for the aerosol-generating article to pass through the passageway and through the control module, the control module further comprising control circuitry and a measurement device; the control circuit includes an excitation coil configured to generate an alternating magnetic field within the passageway of the control module, and the measurement device is configured to determine a value related to a load applied to the control circuit in response to a physical characteristic of the heating element as the heating element passes through the passageway and into the control module; The non-destructive testing apparatus, wherein the control module is further configured to determine whether the determined value of the tested heating element corresponds to a predetermined value of a predetermined heating element. Example 2: The test apparatus described in Example 1, wherein the determined value is a value indicative of the apparent electrical resistance of the heating element. Example 3: A test apparatus as described in any one of Examples 1 or Ex2, wherein the measuring device comprises a current measuring device for determining a DC current drawn by the control circuit from a DC power supply of the apparatus, and the measuring device is configured to determine an electrical resistance value of the control circuit from a ratio of the determined DC current and a DC voltage applied to the control circuit. Example 4: 4. The testing apparatus of any one of claims 1 to 3, wherein the control circuit of the control module is configured to provide a power pulse for powering the excitation coil. Example 5: 5. The test apparatus according to any one of the preceding claims, wherein the excitation coil is part of an LRC circuit of the measurement device. Example 6: 6. The test apparatus according to any one of the preceding embodiments, wherein the control circuit is configured to operate the excitation coil at low power. Example 7: 7. The test apparatus of example 6, wherein the control circuit is configured to apply a DC voltage in the range of 0.5V to 3V, preferably 1V. Example 8: A testing apparatus as described in any one of Examples 1 to 7, wherein the control module is configured to output acceptance of the aerosol-forming article if the determined value of the tested heating element corresponds to the predetermined value of the predetermined heating element, or to output rejection of the aerosol-generating article if the determined value of the tested heating element does not correspond to the predetermined value of the predetermined heating element. Example 9: The testing device according to any one of the first to eighth embodiments, wherein the excitation coil is disposed within the control module and is disposed so as to surround the passageway. Example 10: The testing apparatus of any one of Examples 1-9, wherein the passageway within the control module is a through hole passing through the control module. Example 11: The testing apparatus of any one of Examples 1-10, further comprising a guide element for guiding the aerosol-generating article into the passageway of the control module. Example 12: 12. The testing apparatus of example 11, wherein the guide element comprises a conveyor for transporting the aerosol-generating article to the control module. Example 13: The testing device of Example 11, wherein the guiding element comprises a slide for guiding the aerosol-generating article over the slide. Example 14: 14. The testing device of any one of Examples 11-13, wherein the guide element comprises a converging guide that converges toward the passage opening. Example 15: 15. The testing apparatus of any one of Examples 1-14, further comprising a reservoir for holding an aerosol-generating article, the reservoir being disposed upstream of the control module. Example 16: The testing device of any one of Examples 1-15, wherein the testing device is disposed between article manufacturing components. Example 17: The testing apparatus of Example 16, wherein the manufacturing components are any one of a rod forming apparatus and a cutting apparatus arranged upstream of the testing apparatus, and any one of a cutting apparatus, an article storage section, and an article packaging apparatus arranged downstream of the testing apparatus. Example 18: The method is Providing an aerosol-generating article comprising a heating element; passing an alternating magnetic field of a control circuit through the aerosol-generating article without heating the heating element; determining a value associated with a load imposed by the heating element applied to the control circuit in response to a physical characteristic of the heating element passing through an alternating magnetic field of the control circuit; and comparing the determined value of the tested heating element with a predetermined value of the predetermined heating element. and comparing the measured value with the measured value of the heating element in the aerosol-generating article. Example 19: The method of example 18, further comprising accepting the aerosol-generating article if the difference between the determined value of the tested heating element and the predetermined value is within a predetermined threshold, or rejecting the aerosol-generating article if the difference between the determined value of the tested heating element and the predetermined value exceeds a predetermined threshold. Example 20: 20. The method according to any one of Examples 18 to 19, wherein a value indicative of the apparent electrical resistance of the heating element is determined. Example 21: The method according to any one of embodiments 18 to 20, comprising measuring the DC current drawn from the DC power supply by the control circuit and determining the electrical resistance value of the control circuit from the ratio of the determined DC current to the DC voltage applied to the control circuit. Example 22: 22. The method according to any one of claims 18 to 21, further comprising providing a power pulse from the control module to the excitation coil. Example 23: The method according to any one of embodiments 18 to 22, wherein a DC voltage between 0.5V and 3V is applied to the control circuit. Example 24: The method of any one of Examples 18 to 23, wherein the aerosol-generating article, when tested, passes through an alternating magnetic field at a speed of between 0 m / s and 40 m / s. Example 25: The method of claim 24, wherein the aerosol-generating article, when tested, passes through an alternating magnetic field at a speed of between 10 m / s and 30 m / s. Example 26: The method of any one of claims 18 to 25, wherein the aerosol-generating article passes through the center of the excitation coil. Example 27: 27. The method of claim 26, wherein the aerosol-generating article is guided to the center of the excitation coil. Example 28: 28. The method of any one of claims 18 to 27, wherein the aerosol-generating article is conveyed by a conveying means through the alternating magnetic field. Example 29: The method of any one of claims 18 to 28, wherein the aerosol-generating article falls by gravity through the alternating magnetic field. Example 30: 30. The method of any one of Examples 18 to 29, further comprising providing a reservoir containing an aerosol-generating article comprising a heating element, and guiding the aerosol-generating article from the reservoir into the alternating magnetic field. Example 31: The method of any one of Examples 18 to 30, wherein the aerosol-generating article is rod-shaped. Example 32: The method of claim 31, wherein the aerosol-generating article is a rod-shaped aerosol-generating substrate that includes a heating element. Example 33: The method of any one of Examples 18 to 32, wherein the aerosol-generating article has a final length of a consumable tobacco plug for use in an aerosol generating device. Example 34: The method of any one of Examples 18 to 32, wherein the aerosol-generating article comprises a plurality of lengths of final lengths of consumable tobacco plugs for use in the aerosol generating device. Example 35: The method according to any one of embodiments 18 to 34, wherein the predetermined value of the predetermined heating element is adapted according to the length of the predetermined heating element. Example 36: The method of any one of Examples 18-35, wherein the heating element comprises at least one susceptor material. Example 37: The method according to any one of embodiments 18 to 36, wherein the heating element is a multi-layer susceptor arrangement. Example 38: The method of example 37, wherein the multi-layer susceptor arrangement is an elongated multi-layer susceptor arrangement in the form of a strip. Example 39: The method of any one of Examples 37-38, wherein a first layer of a first susceptor material of the multi-layer susceptor arrangement and a second layer of a second susceptor material of the multi-layer susceptor arrangement are in intimate physical contact with each other, and the second susceptor material has a Curie temperature of less than 500 degrees Celsius. Example 40: 40. The method of any one of embodiments 39, wherein the first susceptor material does not have a Curie temperature or has a Curie temperature greater than 500 degrees Celsius. Example 41: The method of any one of Examples 39-40, wherein the first susceptor material comprises or consists of a metal, such as ferritic iron, or stainless steel, particularly grade 410, grade 420, or grade 430 stainless steel. Example 42: The method of any one of embodiments 39-41, wherein the second susceptor material comprises or consists of a Ni-Fe alloy containing 75 weight percent to 85 weight percent and 10 weight percent to 25 weight percent Fe. Example 43: Ni-Fe alloy contains the following elements: The method of example 42, further comprising one or more of Co, Cr, Cu, Mn, Mo, Nb, Si, Ti, and V. Example 44: The method according to any one of embodiments 39 to 43, wherein the first layer has a layer thickness in the range of 20 micrometers to 60 micrometers. Example 45: The method of any one of embodiments 39 to 44, wherein the second layer has a layer thickness in the range of 4 micrometers to 20 micrometers. Example 46: The method of any one of examples 39-45, wherein the multi-layer susceptor arrangement comprises a third layer intimately connected to the second layer, the third layer comprising a third susceptor material. Example 47: 47. The method of embodiment 46, wherein the third susceptor material is at least partially identical to the first susceptor material. Example 48: 48. The method of any one of embodiments 46-47, wherein the third layer comprises or consists of an austenitic stainless steel, specifically one of 301 stainless steel, 304 stainless steel, 316 stainless steel, or 316L stainless steel. Example 49: The method of any one of examples 46 to 48, wherein the third layer has a layer thickness in the range of 2 micrometers to 6 micrometers.

[0077] The embodiments will now be further described with reference to the following figures: [Brief description of the drawings]

[0078] [Figure 1] FIG. 1 shows a schematic diagram of an exemplary embodiment of a test device. [Diagram 2] FIG. 2 shows a schematic diagram of the technical operating principle of the test device of FIG. [Diagram 3] FIG. 3 is a test apparatus setup for measuring a dropped article with a heating element. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0079] Figure 1 illustrates diagrammatically an article 1 passing through a test apparatus 2. The article 1 comprises a heating element (not shown), for example an inductively heated heating element such as a multi-layer susceptor arrangement. The article 1 is preferably a rod-shaped aerosol-generating article comprising a heating element and an aerosol-forming substrate. In particular, the article 1 is a tobacco-containing substrate in which a susceptor is embedded. The article may also be a final consumable product, and thus a tobacco plug having a heating element and an additional segment, for example a filter element.

[0080] To check the quality of the heating element in the article 1, the article 1 passes through the testing device 2 via a passage 22. Depending on the arrangement of the testing device 2, the article 1 may be guided through the passage 22 and through the testing device 2, for example by a conveyor (not shown). The article may also be guided into the passage 22 of the testing device 2 and may fall through the passage under the influence of gravity, for example vertically downwards as shown in FIG.

[0081] The direction of movement 100 of the article 1 to be tested may therefore be horizontal or vertical, or anything between horizontal and vertical.

[0082] The vertical arrangement has passages that may be disposed exactly vertically or may be disposed at a number of degrees offset from the exact vertical arrangement, for example, the vertical passages are disposed at 0 degrees to 45 degrees, preferably 0 degrees to 30 degrees, such as 0 degrees to 15 degrees, where 0 degrees corresponds to the exact vertical arrangement.

[0083] The test fixture 2 comprises a control module 13. Located within the control module 13 is an excitation coil 11 which forms part of an LRC measurement circuit indicated at block 130.

[0084] The test device 2 operates differently from the coil module used in the commercial device. In a real device, a heating element is required to heat the aerosol-forming substrate of the article 1 for aerosol formation.

[0085] In the test fixture 2, the excitation coil 11 is supplied with a low voltage, for example around 1V.

[0086] The LRC circuit is connected to a processor to collect output data from the control module 13 .

[0087] The output and determined result of the test is typically the equivalent resistance of an excitation coil 11 disposed inside the test device 2 when the article 2 and, accordingly, the heating element are located inside the coil 11.

[0088] The control module 13 with the passage 22 allows the articles to be tested and passed through the passage, allowing measurements to be taken during the passage of the articles through the control module 13. This allows for sample testing in a high speed process. It is possible to analyse a large number of articles at high speed, for example with an article speed passing through the passage 22 at about 10 m / s to 30 m / s. The speed of the articles 1 may depend on the capacity of the measuring device.

[0089] The basic feedback provided by the test apparatus 2 is to ensure that all tested articles have a similar response in terms of the equivalent resistance recorded by the apparatus.

[0090] Since the testing device 2 is a non-destructive test, the tested article 1 can still be used after the test. For this reason, the testing device 2 is suitable to be arranged along a production line of articles, where defective articles can be easily and quickly sorted out.

[0091] In Fig. 2 the basic technical operating principle of the measuring part of the test device 2 is diagrammatically illustrated. The load 111 represents the impedance generated by the system comprising the excitation coil 11 arranged in the control module 13 and the heating element, in particular a susceptor, located in the article 1 to be tested.

[0092] The system transmits a signal 112 and then measures the resulting voltage V and the current I absorbed by the control circuit. By knowing the characteristics of the excitation coil 11 it is possible to obtain a measure of the physical properties of the heating element.

[0093] FIG. 3 shows diagrammatically the set-up of a test apparatus 2 adapted to measure a falling article 1 passing through the test apparatus 2 .

[0094] The storage 30 in the form of a hopper contains a plurality of articles to be tested, e.g. elongated sticks carrying the susceptor elements to be tested. The hopper may preferably contain several hundred sticks, e.g. 20o-300 sticks. The sticks may be final consumables with elements comprising a susceptor arrangement or may be tobacco rods with the susceptor arrangement mainly disposed inside the tobacco rod.

[0095] From the hopper, the articles 1 fall downwards and are positioned along a vertical line in a slide assembly 31 disposed below the reservoir 30. From the slide assembly 31, the articles reach the test device 2. The slide assembly 31 is positioned such that the falling articles are guided into the passage 22 in the test device. The tested articles leave the passage 22, pass through a measurement and indicator portion 33 and then into a container 34 that collects the articles.

[0096] The measurement and indicator portion 33 includes a sensor 110 , a stopper 332 and an indicator light 333 .

[0097] The indicator lights 333 may indicate the status of the test equipment or whether the tested article is acceptable or defective, for example, by changing the color of the light. For example, one color may indicate that the equipment is ready to measure, that a measurement is in progress, that the measured article is within the product tolerance, or that the article is outside the product tolerance.

[0098] The sensor 110 may be the control module 13 described above in FIG. 1 for measuring an article passing through a testing apparatus, and the equivalent electrical resistance of the susceptor element is measured.

[0099] The stopper 332 maintains the article in a measurement position inside the sensor 110. The stopper 332 stops the article as it falls through the testing apparatus and releases the article after the measurement so that the article rests within the container 34.

[0100] The test conditions are preferably kept constant throughout the measurement cycle, e.g., over a certain number of tested articles, or over a certain test time, e.g., 24 hours. For example, the test conditions include about 20-24 degrees Celsius and about 40-60 percent relative humidity. An acceptable deviation from the desired electrical resistance is, e.g., ±40 milliohms for an electrical resistance of the susceptor element of 300-450 milliohms. The deviation is preferably determined relative to an average value over, e.g., five measurements.

[0101] For the 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 as being modified by the term "about." Also, all ranges include the maximum and minimum points disclosed, and include any intermediate ranges therein, which may or may not be specifically recited herein. Thus, in this context, the number A is understood as A±5%. Within this context, the number A may be considered to include values ​​that are within the general standard error for the measurement of the property that the number A modifies. The number A may, in some instances used in the appended claims, deviate by the percentages recited above, without materially affecting the basic and novel properties of the claimed invention. Also, all ranges include the maximum and minimum points disclosed, and include any intermediate ranges therein, which may or may not be specifically recited herein.

Claims

1. 1. A non-destructive testing apparatus for testing a heating element within an aerosol-generating article, said testing apparatus comprising: a control module having a passageway for an aerosol-generating article to pass through said passageway and pass said control module, said control module further comprising control circuitry and a measurement device; the control circuit includes an excitation coil configured to generate an alternating magnetic field within the passageway of the control module, and the measurement device is configured to determine a value related to a load applied to the control circuit in response to a physical characteristic of the heating element as the heating element passes through the passageway and into the control module; The non-destructive testing apparatus, wherein the control module is further configured to determine whether the determined value of the tested heating element corresponds to a predetermined value for a predetermined heating element.

2. 2. The testing device of claim 1, wherein the determined value is a value indicative of the apparent electrical resistance of the heating element.

3. 3. A test device according to claim 1, wherein the excitation coil is part of an LRC circuit of the measurement device.

4. The test apparatus of claim 1 , wherein the control circuit is configured to operate the excitation coil at low power.

5. 5. A test device according to claim 4, wherein the control circuit is configured to apply a DC voltage in the range of 0.5V to 3V, preferably 1V.

6. 2. The test apparatus of claim 1, wherein the excitation coil is disposed within the control module and surrounding the passageway.

7. 10. The testing device of claim 1, further comprising a guide element for guiding the aerosol-generating article into the passageway of the control module.

8. 8. The test device of claim 7, wherein the guide element comprises a slide for guiding the aerosol-generating article on the slide.

9. 1. A non-destructive testing method for testing a heating element within an aerosol-generating article, said method comprising: providing an aerosol-generating article comprising a heating element; passing an alternating magnetic field of a control circuit through the aerosol-generating article without heating the heating element; determining a value related to a load applied to the control circuit by the heating element in response to a physical characteristic of the heating element passing through the alternating magnetic field of the control circuit, and comparing the determined value for the tested heating element with a predetermined value for a predetermined heating element; Non-destructive testing methods, including:

10. 10. The method of claim 9, further comprising accepting the aerosol-generating article if the difference between the determined value of the tested heating element and the predetermined value is within a predetermined threshold, or rejecting the aerosol-generating article if the difference between the determined value of the tested heating element and the predetermined value exceeds the predetermined threshold.

11. 11. The method according to claim 9, wherein a DC voltage of 0.5V to 3V is applied to the control circuit.

12. 11. A method according to claim 9 or 10, wherein the aerosol-generating article, when tested, passes through the alternating magnetic field at a velocity of between 0 m / s and 40 m / s.

13. 13. The method of claim 12, wherein the aerosol-generating article, when tested, passes through the alternating magnetic field at a velocity of between 10 m / s and 30 m / s.

14. 11. The method of claim 9 or 10, wherein the aerosol-generating article falls through the alternating magnetic field by gravity.

15. The method of claim 9 or 10, wherein the heating element is a multi-layer susceptor arrangement.

Images