A method for measuring the temperature field of a surrounding heated cigarette

Abstract

The present invention discloses a method for measuring the temperature field of a cigarette heated in an enclosed manner, comprising the following steps: according to the axial depth of the cigarette point to be measured, an axial hole is opened in the cigarette, the hole being opened from the inhalation end of the cigarette, and a temperature sensor is implanted in the hole; the cigarette with the implanted temperature sensor is placed in a heating device, and after the device is heated, the temperature data of the point to be measured is acquired through the temperature sensor; the radial position of the temperature sensor in the cross section of the cigarette is measured, and the measurement is repeated using S1-S3 to obtain temperature distribution data of the cigarette at different axial depths and radial positions, thereby producing a temperature distribution map. The present invention can accurately obtain the actual position of the temperature sensor in the cigarette and obtain temperature data of each point in the cigarette during the inhalation process.

Description

Technical Field

[0001] The present invention relates to the field of temperature field testing of cigarette products, and in particular to a method for measuring the temperature field of an enclosed heated cigarette. Background Art

[0002] A cigarette itself is a complex reactor, undergoing a series of chemical reactions, including cracking. The internal temperature distribution of a cigarette is a key factor influencing the formation of smoke components. Measuring the temperature distribution during cigarette heating is crucial for studying the formation and transport of smoke aerosols, as well as the final composition of the smoke. Currently, there has been considerable research and development into methods and instruments for determining the internal temperature field of a cigarette's combustion cone during the traditional combustion and inhalation process.

[0003] For example, patent publication number CN103983370B discloses a method for detecting the temperature distribution of a cigarette during smoking, a single-channel temperature measurement device, and a system for correlating cigarette parameters with smoking temperature. The method includes: after a cigarette to be tested is lit, at least one thermocouple wire collects the temperature of the cigarette in real time, and a single-channel smoking machine initiates a puffing operation. The cigarette to be tested is placed in the cigarette holder of the single-channel smoking machine, and the thermocouple wire is placed in a corresponding temperature measurement position on the cigarette to be tested. A temperature collector reads and stores the temperature data collected by the thermocouple wire in real time during the puffing operation of the single-channel smoking machine. A temperature distribution determination unit determines the temperature distribution of the cigarette to be tested during smoking based on the temperature data. This patent allows for customized smoking procedures and online testing of the temperature distribution of cigarettes during smoking, with high repeatability and low cost. However, this patent is only applicable to traditional cigarettes.

[0004] In the cigarette industry, especially for low-temperature slim cigarettes, tobacco segments are heated within the device. The device wraps around the cigarette, leaving only the filter tip exposed. This makes the traditional side-punching method of inserting thermocouples no longer suitable. Currently, it's still difficult to accurately measure the internal temperature distribution of a cigarette during puffing. Accurately implanting temperature sensors at the desired location within the cigarette and determining their placement after implantation remain challenges in the industry. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a temperature field measurement method for a cigarette with surround heating, in view of the shortcomings of the existing technology, to accurately obtain the actual position of the temperature sensor in the cigarette, and to obtain the temperature data of each point in the cigarette during the smoking process.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0007] A method for measuring the temperature field of a surrounding heated cigarette comprises the following steps:

[0008] S1. Drill a hole in the axial direction of the cigarette according to the axial depth of the test point. The hole is opened from the inhalation end of the cigarette and the temperature sensor is implanted in the hole.

[0009] S2. Place the cigarette with the temperature sensor embedded in it into a heating device. After the device is heated, the temperature data of the measured point is obtained through the temperature sensor.

[0010] S3, measuring the radial position of the temperature sensor in the cross section of the cigarette;

[0011] S4. Repeat S1-S3 to perform measurements, obtain temperature distribution data of cigarettes at different axial depths and radial positions, and prepare a temperature distribution map.

[0012] The cigarette is different from traditional directly ignited cigarettes and is heated by an enveloping heating method. The axial direction of the cigarette is the direction of the central axis of rotation of the cigarette, and the radial direction is perpendicular to the axial direction.

[0013] This method creates an axial deep hole in a cigarette and inserts a temperature sensor into the tobacco section of the cigarette from the inhalation end. By controlling the axial position of the deep hole on the cigarette cross section and the temperature sensor's implantation depth, effective temperature sensor implantation is achieved. Furthermore, considering that the distribution of tobacco flakes in different cigarettes and the influence of the temperature sensor's position during the axial deep hole creation process can cause measurement errors, the final position of the temperature sensor is accurately determined by precisely cutting and measuring the heated cigarette.

[0014] The radial position of the temperature sensor in the cross section of the cigarette can be measured after cutting or directly detected by X-rays.

[0015] The specific steps of measuring after cutting are as follows: in S3, the heated cigarette is removed from the apparatus, the position of the temperature sensor in the cigarette is maintained unchanged, a radial cut is made on the cigarette so that the end of the temperature sensor located inside the cigarette is just exposed without causing deformation of the cigarette, and the radial position of the temperature sensor in the cross section of the cigarette is measured. The radial position of the temperature sensor in the cross section of the cigarette can be measured directly using a measuring instrument, such as a vernier caliper, or by optical means such as photographic measurement.

[0016] Direct X-ray detection eliminates the need to cut the cigarette, and uses X-rays to determine the radial position of the temperature sensor in the cigarette cross section. The radial position of the temperature sensor in the cigarette cross section is the radial position where the insertion end of the temperature sensor is located in the cigarette cross section.

[0017] In S1, considering that the tobacco segments or other materials of some cigarettes are not evenly distributed, tobacco slices and other materials will offset the radial position of the temperature sensor to a certain extent during the axial deep hole drilling process, making the distribution of the temperature sensor position in the region somewhat random. Therefore, during the cigarette punching process, there is no need to deliberately determine the radial position of the cigarette to be measured before punching. Usually, holes can be punched from the center axis, and each cigarette is measured once. After measuring multiple sets of temperature distribution data at the same axial depth, it is determined whether the measurement needs to be continued based on whether the data of the radial position of the temperature sensor in the cross section of the cigarette in S3 meets the requirements of the difference method for point selection. If the radial position data in S3 has covered the selected point required by the difference method, the measurement of the axial depth is completed. If the radial position data has not yet covered the selected point required by the difference method, the radial position of the punching can be slightly offset to facilitate the acquisition of the radial position required for measurement.

[0018] Furthermore, in S4, after measuring multiple sets of temperature distribution data at the same axial depth, the axial depth is changed and multiple measurements are performed at different axial depths.

[0019] Furthermore, in S1, when the heating device adopts a non-uniform heating mode, the radial position is a coordinate point corresponding to a coordinate system established with the center of the cigarette as the center, and in S2, the cigarette with the temperature sensor implanted is placed in the heating device in the direction of the coordinate axis.

[0020] If the heating device adopts a uniform heating mode, when analyzing and processing the data, for a uniformly heated device, the temperature sensor position can be mapped according to the symmetry of the heating body. The temperature distribution inside the cigarette is related to the axial depth and radial radius, so the point is selected according to the axial depth.

[0021] If the heating device uses a non-uniform heating method, the temperature distribution inside the cigarette is also related to the specific position of the cigarette in the heating device. Therefore, it is necessary to select points based on the axial depth and the coordinate points of the coordinate system established with the center of the cigarette as the center, and ensure that the cigarette with the implanted temperature sensor is placed in the heating device in the direction of the coordinate axis. Two fixed points can be selected on the cigarette and the heating device. Each time a cigarette is added to the heating device, these two fixed points are ensured to be aligned.

[0022] Furthermore, in S1, the intended insertion depth of the temperature sensor is marked, and the marked end of the temperature sensor is fully inserted into the hole of the cigarette. The intended insertion depth of the temperature sensor is consistent with the depth of the hole. The accurate insertion depth is ensured by the two parameters of the axial depth of the hole and the intended insertion depth of the temperature sensor.

[0023] Furthermore, in S2, a cigarette with an embedded temperature sensor is inserted into the device at the same time before the test. When the test time arrives, the heating device is immediately activated, and the data recording instrument is immediately activated after the device is heated. By controlling the operation time of each step, the consistency of the test conditions is guaranteed.

[0024] Furthermore, in S4, the temperature distribution data at multiple locations with the same axial depth and radial position are averaged. Because the location of the openings in the cigarette is somewhat random, the temperature sensor positions measured in S3 may overlap somewhat on the cross-section of the cigarette. When the same location points appear, the measured temperature data are averaged.

[0025] Furthermore, in S4, the temperature distribution data of the cigarettes is processed using an interpolation algorithm. By using the temperature data of the measured position points and processing them using an interpolation algorithm, the temperature data of other position points can be obtained, thereby reducing the number of measurements.

[0026] Furthermore, in S1, a straight-axis punch is used to punch holes. In order to ensure the working efficiency of the punching, a straight-axis punch is used to punch holes.

[0027] Furthermore, in S1 , the diameter of the opening is consistent with the diameter of the temperature sensor.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] 1. The present invention selects an axial depth from the smoking end of the cigarette to drill a deep hole in the positive axial direction, implants the temperature sensor at the selected depth, and implants the temperature sensor into the position to be measured inside the cigarette;

[0030] 2. Considering that tobacco segments or other materials in some cigarettes are not evenly distributed, tobacco slices and other materials will offset the radial position of the temperature sensor to a certain extent during the axial deep hole drilling process. By accurately cutting the heated cigarette, exposing the position of the temperature sensor at the tobacco end, and measuring the actual position of the temperature sensor, the temperature sensor can be accurately positioned, the actual position of the temperature sensor in the cigarette can be accurately obtained, and the temperature data of each point in the cigarette during the heating process can be obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a structural diagram of the positive axis puncher.

[0032] Figure 2 Schematic diagram of cigarette marking and cigarette cutting after heating in Example 1.

[0033] Figure 3 Schematic diagram of measuring radial distance using a vernier caliper.

[0034] Figure 4This is a record of the temperature distribution of a 45mm cross section of an enclosed cigarette.

[0035] Figure 5 This is the temperature distribution of the 45mm cross section of the treated enclosed cigarette.

[0036] Figure 6 To establish a full-plane temperature data cloud map by interpolating key point temperature test data.

[0037] Figure 7 To establish the whole cigarette temperature data by interpolating the temperature distribution data of the key depth plane.

[0038] Figure 8 Schematic diagram of establishing a coordinate system for cigarettes.

[0039] Figure 9 This is a schematic diagram of the position markings of the cigarettes and the heating device in Example 2.

[0040] Figure 10 This is a schematic diagram of placing a cigarette into a heating device in Example 2.

[0041] Figure 11 This is the coordinate system establishment and thermocouple position measurement in Example 2. DETAILED DESCRIPTION

[0042] Example 1

[0043] Temperature field data was measured at a 45mm cross-section of a wrapped cigarette. The experiment was conducted at 22°C and 61% humidity, with identical heating conditions and duration, and 15-minute intervals between each test. The heating device in this embodiment employs a uniform heating method, and the temperature sensor is a thermocouple.

[0044] Step 1:

[0045] like Figure 1 As shown, insert the cigarette 2 into the holder 1, and select the alignment device 3 with the deep hole positioned at the central axis of the cigarette 2. The position of the deep hole is determined by the radial distance of the point to be measured in the cigarette, and is not restricted to the position of the central axis. When the required radial position cannot be obtained by multiple drillings, an offset can be made at the central axis so that the radial positions of multiple measured points can meet the requirements of interpolation data processing. Install the holder 1 into the alignment device 3. Use the needle sleeve 4 and the punching needle 5 to drill a deep hole from the end of the cigarette. The depth of the deep hole is determined by the depth of the thermocouple to be implanted. As shown Figure 2 As shown, a label 7 is attached (or the thermocouple wire is bent) at the intended total insertion depth of thermocouple 8, limiting its insertion to a specific depth, for example, 52 mm. The axial depth of the thermocouple is now known, allowing the location of the thermocouple's measurement point to be determined. A cigarette with the thermocouple implanted is placed in the device, heated, and temperature data at the desired measurement point is obtained.

[0046] Of course, it is also possible to consider using other existing punching devices to perform axial punching on the cigarette.

[0047] Considering that tobacco segments or other materials in some cigarettes are not evenly distributed, tobacco sheets and other materials will offset the radial position of the thermocouple to a certain extent during the axial deep hole drilling process, making the distribution of the thermocouple position in the region somewhat random. At this time, the thermocouple needs to be positioned more accurately.

[0048] Step 2:

[0049] Considering the heat transfer characteristics of an object, there are slight differences in the initial temperatures at different radial positions. Therefore, data alignment is performed based on the start time recorded by the instrument. A unified test benchmark is used for data alignment, which means that the starting conditions for each instrument data recording are unified. Before each test begins, a cleaned thermocouple is implanted into the cigarette to be tested and the test is awaited. 5-10 seconds before the test, the cigarette to be tested is inserted into the device. When the test time expires, the heating device is immediately activated. After receiving startup feedback such as vibration from the device, the recording instrument is immediately activated. At this point, the starting conditions of the recorded data are consistent, and the starting ends of the data are aligned.

[0050] Step 3:

[0051] like Figure 2 As shown, remove the heated cigarette and carefully remove the cigarette 2 from the device by positioning the label 7, keeping the thermocouple 8 in the cigarette unchanged. Use a sharp blade 6 to make a vertical cut at the location where the thermocouple 8 is implanted. A sufficiently sharp blade can effectively cut the cigarette 2, leaving the thermocouple 8 exposed without causing any deformation of the cigarette.

[0052] For central axis symmetrical heating devices such as surround heating or central pin heating, assuming that the tobacco distribution of the cigarette is uniform, the temperature is only related to the radial position of the thermocouple 8 on the cigarette, and has nothing to do with the center angle. In this case, it is only necessary to measure the radial distance between the thermocouple 8 and the outer wall of the cigarette. Ensure that the position of the thermocouple 8 does not change, and connect the center of the cigarette cross section to the thermocouple 8, as shown in the figure. Figure 3 As shown, the radial distance between the thermocouple and the outer wall of the cigarette is measured using a high-precision measuring tool, a vernier caliper. Combined with the insertion depth of the thermocouple 8, the precise actual measurement position of the thermocouple 8 can be obtained, which corresponds to the experimental data.

[0053] Based on the symmetry of the heating body, the thermocouple positions can be mapped, making the thermocouple positions more dense and effectively reducing the number of points to be measured. The offset of the tobacco sheet from the thermocouple position will only appear in a small area near the positioning deep hole. By sampling multiple samples, when the number of measured samples is sufficient, the measurement position of the thermocouple will cover all the data collection points to be measured. Combined with the aforementioned method of cutting the heated cigarette to achieve precise positioning of the thermocouple, the experimental parameters of all characteristic positions are integrated to achieve full-section temperature field distribution measurement. In addition, eliminating singular measurement results and performing statistical analysis on the temperature curves at the same position can effectively reduce the impact of errors in the measurement process.

[0054] Using the above method, a total of 21 cigarettes were tested for temperature, and the data obtained were as follows: Figure 4 shown.

[0055] Step 4:

[0056] Same-position data processing: analyze and process the temperature data at the same position, and perform average processing on the temperature distribution data of multiple identical axial depths and radial positions.

[0057] After analyzing and processing the data, all characteristic position temperature parameters that meet the cross-sectional temperature field distribution test requirements are obtained, totaling 13 temperature data curves. The temperature distribution of the 45mm cross section of the enclosed cigarette at different radial positions is plotted as follows: Figure 5 .

[0058] At this point, a vertical line is drawn at a certain moment in the graph, for example, time t = 44s, to obtain the temperature distribution of the enclosed cigarette at a depth of 45mm after heating for 44s.

[0059] Step 5:

[0060] In step 4, the test results can be reconstructed using some interpolation algorithms to obtain richer temperature distribution information, such as the temperature distribution cloud map of a cross section at a certain depth. Furthermore, some interpolation algorithms can be used to reconstruct the temperature distribution cloud maps of cross sections at different depths to obtain a three-dimensional temperature distribution cloud map of the entire cigarette:

[0061] like Figure 6As shown, after obtaining the main temperature data of the plane, an interpolation algorithm is used to interpolate the temperatures of the remaining positions. For example, through experiments, the corresponding temperature change curves T(A), T(B), T(C), and T(D) of the four positions A(xA, yA), B(xB, yB), C(xC, yC), and D(xD, yD) have been obtained. According to the variation law of the temperature change curve, an appropriate linear or nonlinear interpolation method f(T) is adopted to obtain E(xE, yE) at time t0. Interpolation processing is performed for all time t to obtain the corresponding temperature change curve T(E)=∫f(T)dt at E(xE, yE). After completing the interpolation processing of all the main temperature data, a temperature distribution cloud map of the entire plane can be obtained. This cloud map depicts the temperature variation law of the cross section of the cigarette at a specified depth. It should be noted that the coordinate representation used in the example can be Cartesian coordinates or other forms of expression such as polar coordinates.

[0062] According to the distribution of heating device characteristics, the key axial depth h of the cigarette is selected, and the temperature distribution of the cross-sections corresponding to these depths will jointly characterize the temperature distribution of the entire cigarette. For example, through experiments and the interpolation method described above, the temperature data cloud maps of two consecutive key axial depth planes are obtained. According to the change law of the temperature change curve, a suitable linear or nonlinear difference method f(T) is adopted to interpolate the temperature data of position A1 of the h1 plane and the temperature data of the corresponding position A2 of the h2 plane, and obtain the temperature data T(A3) of the position A3 corresponding to the interpolation plane h3. When the temperature parameters of all points in the plane are processed, the full-plane temperature data cloud map of the interpolation plane h3 can be obtained. When the interpolation processing of all key axial depth planes h is completed, the real-time temperature data of the entire cigarette can be obtained, such as Figure 7 shown.

[0063] Example 2

[0064] The difference between Example 2 and Example 1 lies in step 1. Step 1 in Example 1 is applicable to a device for uniform heating, while step 1 in Example 2 has no limitation and can be applied to any smoking device.

[0065] Step 1:

[0066] For any cigarette and device, regardless of its heating mode, heating distribution, and device shape, it is only necessary to establish a coordinate system (which can be a Cartesian coordinate system or other coordinate systems, such as an angular coordinate system) with the center of the cigarette cross section as the circle point, such as Figure 8As shown, using high-precision measuring instruments to measure the thermocouple's position parameters (Cartesian coordinates correspond to longitudinal and lateral position parameters, angular coordinates correspond to angular and radial position parameters, and other coordinate systems correspond to their own settings) can obtain the actual measurement position of the thermocouple. Symmetry can reduce the amount of measurement data required, but is not essential.

[0067] Use a pen or other tool to make cross marks on the cigarette insertion port and the cigarette surface of the device. The adjacent marks are perpendicular to each other and the end of a marking line is specially marked, such as Figure 9 (The number, type and angle of the markings are only examples and may be other marking forms); align the cross marks between the cigarette and the device, such as Figure 10 , insert the thermocouple into the specified depth of the experiment, perform heating and data collection; remove the heated cigarette, pass through the cross mark position, keep the position of the thermocouple in the cigarette unchanged, and carefully remove the cigarette from the device 2. Use a sharp blade to make a vertical cut at the thermocouple implantation position. A sharp enough blade can effectively cut the cigarette, so that the thermocouple is just exposed without causing the shape of the cigarette to deform; use the intersection of the cross mark line of the cigarette as the origin, and the direction from the origin to the special mark cross mark line as the positive direction of the y-axis (can be the x-axis), and establish a plane rectangular coordinate system, such as Figure 11 As shown in the figure, use a high-precision measuring tool to measure the vertical distance between the thermocouple and the coordinate axis. Combined with the insertion depth of the thermocouple, the actual measurement position of the thermocouple can be obtained and correspond to the experimental data.

[0068] The contents illustrated in the above embodiments should be understood as these embodiments are only used to more clearly illustrate the present invention, and are not used to limit the scope of the present invention. After reading the present invention, various equivalent modifications of the present invention by those skilled in the art shall fall within the scope defined by the claims attached to this application.

Claims

1. A method for measuring the temperature field of a cigarette heated in an enclosed manner, characterized in that The following steps are involved: S1. Drill a hole in the axial direction of the cigarette according to the axial depth of the test point. The hole is opened from the inhalation end of the cigarette and the temperature sensor is implanted in the hole. S2. Place the cigarette with the temperature sensor embedded in it into a heating device. After the device is heated, the temperature data of the measured point is obtained through the temperature sensor. S3, measuring the radial position of the temperature sensor in the cross section of the cigarette; S4. Repeat S1-S3 to perform measurements, obtain temperature distribution data of cigarettes at different axial depths and radial positions, and generate a temperature distribution map; In S4, after measuring multiple sets of temperature distribution data at the same axial depth, the axial depth is changed and multiple measurements are performed at different axial depths; In S4, the temperature distribution data of multiple identical axial depths and radial positions are averaged; In S4, an interpolation algorithm is used to process the cigarette temperature distribution data.

2. The temperature field measurement method according to claim 1, characterized in that: In S1, when the heating device adopts a non-uniform heating mode, the coordinate point corresponding to the coordinate system established with the center of the cigarette as the center is set, and in S2, the cigarette with the temperature sensor implanted is placed into the heating device in the direction of the coordinate axis.

3. The temperature field measurement method according to claim 1, characterized in that: In S1, a mark is made at the intended implantation depth of the temperature sensor, and the marked end of the temperature sensor is fully inserted into the hole of the cigarette. The intended implantation depth of the temperature sensor is consistent with the depth of the hole.

4. The temperature field measurement method according to any one of claims 1 to 3, characterized in that: In S2, a cigarette with an implanted temperature sensor is inserted into the device at the same time before the test. When the test time arrives, the heating device is immediately started, and the data recording instrument is immediately started after the device is heated.

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