Nondestructive testing method for tightness of cigarette packet packaging

Abstract

This application provides a non-destructive testing method for the tightness of a cigarette packet (10) package. The method includes the steps of placing a cigarette packet (10) to be tested in an airtight chamber (9), using an equilibrium chamber (6) to quickly create a stable negative pressure in the airtight chamber (9), and continuously measuring the pressure change in the airtight chamber (9) until these two pressures reach equilibrium. The method establishes a data model by using physical process analyses of Darcy's law, Fick's law of diffusion, and molecular kinetics. This method transforms the conventional destructive testing of the tightness of a cigarette packet (10) into a non-destructive testing, the results of which have clear physical meaning, and the testing time for a single sample is reduced to one-fifth of the time required for destructive testing. TIFF2022550923000008.tif69135

Description

[Technical field]

[0001] The present invention relates to the field of tobacco quality testing, and more particularly to a method for non-destructive testing of the tightness of cigarette packets. [Background technology]

[0002] 2. Background of the Invention Cigarette packaging is the final manufacturing step of finished cigarettes. With the development of manufacturing technology, the cigarette packaging process mainly uses machines to seal the folds at both ends of the cigarette box. If poorly sealed cigarettes are stored for a long time, they will develop mildew in a humid environment and become dry and brittle in a dry climate. At the same time, a large amount of tobacco aroma will also leak out, which will directly affect the interests of consumers and the credit of cigarette manufacturers. In recent years, some consumers have pointed out that some cigarettes have mildew and cracks due to drying. It can be seen that measuring the sealing degree of cigarette boxes is important for improving cigarette packaging technology and increasing the sealing degree of cigarette boxes.

[0003] Sealing test was first applied to military products, and sealing is one of the essential measures to ensure the reliable function of military products after long-term storage. With economic development and technological progress, people have increasingly higher requirements for the performance and quality of packaging, and the sealing of some products has also been set up with corresponding national standards. As for the sealing test for packaging, there are existing methods such as inflation method, visual method, talc method, sealing performance tester, air bubble method, etc.

[0004] The inflation method is widely used. ASTM (American Society for Testing and Materials) F2095 describes a method to measure the tightness of a package by inflating the inside of the package and gradually attenuating the pressure, which is a destructive detection method. At the same time, the pressure control of the expansion has a great influence on the test result (average leakage rate formula). It is a destructive test method and is suitable for testing soft packs of cigarettes. For hard packs of cigarettes with boundary restrictions, the inflation test can neither be applied nor applied to the tightness test of cigarette packs.

[0005] In 1998, the State Tobacco Monopoly Administration issued the industry standard YC / T140-1998 "Inflation test method for sealing of cigarette packs". This method is only suitable for measuring the sealing of soft-pack cigarettes and has low test accuracy. This method was abolished in 2013.

[0006] The above method is not suitable for testing the seal of cigarette packs. A Chinese patent (Publication No.: CN 104792470 A (Patent Document 1)) describes a method for measuring the seal of cigarette packs, which is based on pressure sensing of the seal of cigarette packs and can identify the location of leakage. However, this method requires punching and positioning of cigarette packs. After measurement, the cigarette packs cannot be recycled and there is a risk of being mixed into normal cigarette packs. In addition, the measurement chamber needs to be evacuated at a certain flow rate during measurement, which may damage the film of the cigarette pack and affect the measurement accuracy of the seal of the cigarette pack. This method is also a destructive method for testing the seal of cigarette packs. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] CN 104792470A Summary of the Invention

[0008] In order to overcome the above-mentioned shortcomings of the prior art, the present invention proposes a non-destructive testing method for the tightness of cigarette packets. By means of Darcy's law, which reflects the fundamental law of pressure difference and flow rate in porous media, and Fick's law of diffusion of gas in the presence of concentration gradient, the method establishes a data model through physical process analysis with molecular kinetic theory (gas state equation), to obtain an index of tightness, realizing a non-destructive testing method.

[0009] The non-destructive testing method for the tightness of a cigarette packet includes the following steps: The cigarette pack to be tested is placed in the airtight chamber, and a stable negative pressure (-3500 Pa to -5000 Pa, operation time is less than 5 seconds) is quickly formed in the airtight chamber using the equilibrium chamber; continuing to measure the pressure change in the airtight chamber until equilibrium is reached, and establishing a data model by using Darcy's law, Fick's law of diffusion, and molecular kinetic theory physical process analysis; Based on the pressure and time data in the sealed space, three indices are obtained. Among these, the effective air permeability of the cigarette pack (unit: cm / min, i.e. CORESTA) applies the principle of linear relationship between pressure drop and flow rate when gas flows through a porous medium (Darcy's law); the effective diffusion coefficient "k" of the cigarette pack (unit: m 2 / sec) applies the principle of mass flux and concentration gradient (Fick's Law of Diffusion), which shows a linear relationship when pressure difference or concentration is used as the driving force; the effective leakage area of ​​the cigarette packet, "A" (unit: m 2 ) applies the principle of constant mass balance of the amount of substance passing through the leak point or the gas state equation (kinetic theory). These three indices can independently reflect different sealing degrees of cigarette packages. The higher the three data values, the worse the sealing degree.

[0010] In the above method, a test device for the non-destructive testing method for the sealing of a cigarette packet includes: Pressure regulating valve, vacuum generator, equilibrium chamber, pressure gauge, airtight chamber, cigarette box, differential pressure sensor and computer Including, One end of the vacuum generator is connected to a pressure regulating valve and the other end is connected to a muffler; wherein the pressure regulating valve is connected to an air supply; The vacuum generating device is sequentially connected to the first shutoff valve, the balancing chamber, the pressure gauge, the second shutoff valve, the airtight chamber, the cigarette packet, the differential pressure sensor, and the computer.

[0011] During the testing process, (1) Before starting the test, prepare the tank in the equilibration chamber at a specified vacuum, open the air supply, and close the shutoff valve; (2) Open the first shutoff valve and slowly turn the pressure regulating valve, at this time the vacuum generator is working and the equilibrium chamber generates negative pressure; continue to turn the pressure regulating valve until the pressure gauge shows -3500Pa~-5000Pa, after the pressure gauge pointer is stable, close the first shutoff valve, at this time the negative pressure in the equilibrium chamber is equal to the value shown on the pressure gauge; (3) opening the chamber, placing the cigarette packet in the chamber, and then closing and sealing the chamber; (4) Turn on the computer, open the data acquisition software to connect to the output signal of the micro pressure sensor, and set the data acquisition frequency to 10 Hz; (5) Click on the data acquisition software to start data collection, then immediately open the second shutoff valve and then quickly close it (within 2 to 4 seconds), and record the measured pressure value P t When the temperature stabilizes, stop the data collection, export and save the data, and then Airtight room Open the cigarette box and take out the cigarette box to complete the seal test; if the negative pressure value shown on the pressure gauge is greater than -3500 Pa after several sets of cigarette boxes are tested in succession, repeat these steps; (6) Save the measurement data, and calculate the external volume V1 of the cigarette pack and the final pressure P e , the measured pressure in the airtight chamber P t , time t, and the initial pressure P t0 Based on the data, the data was calculated using three models to determine the effective air permeability of cigarette packs. α ", the effective diffusion coefficient of the cigarette pack "k" and the effective leakage area of ​​the cigarette pack "A" are obtained, and the degree of sealing of the cigarette pack is calculated. The effective air permeability "α" of the cigarette pack, the effective diffusion coefficient "k" of the cigarette pack, and the effective leakage area "A" of the cigarette pack can independently reflect the sealing degree of the cigarette pack, and the larger the value, the worse the sealing degree.

[0012] By the non-destructive testing method for the sealability of cigarette packets of the present invention, the traditional destructive measurement (damage to the cigarette packet) for determining the sealability of cigarette packets is transformed into a non-destructive test; the test results have clear physical meaning, the initial negative pressure is controlled within a range, and the data is obtained with good reproducibility; and the test time for a single sample is shortened to 1 / 5 of the time used in destructive testing. [The present invention 1001] 1. A method for non-destructively testing the tightness of a cigarette packet, comprising the steps of: placing a cigarette packet to be tested in an airtight chamber and using an equilibrium chamber to rapidly create a stable negative pressure in the airtight chamber; Continuing to measure the pressure change in the airtight chamber until equilibrium is reached, and establishing a data model by using Darcy's law, Fick's law of diffusion, and molecular kinetic theory physical process analysis; obtaining three indexes, namely, effective air permeability "α" of the cigarette pack, effective diffusion coefficient "k" of the cigarette pack, and effective leakage area "A" of the cigarette pack, based on the data of pressure and time of the sealed space, the three indexes reflect different sealing degrees, and the larger the values ​​of these three data are, the worse the sealing degree is. [The present invention 1002] A test device used in the non-destructive test method for the tightness of a cigarette packet includes a pressure regulating valve (2), a vacuum generating device (3), an equilibrium chamber (6), a pressure gauge (7), an airtight chamber (9), a cigarette packet (10), a differential pressure sensor (11) and a computer (12); One end of the vacuum generator (3) is connected to the pressure regulating valve (2) and the other end is connected to the muffler (4); A pressure regulating valve (2) is connected to an air supply source (1), A vacuum generating device (3) is connected in sequence to a first shutoff valve (5), an equilibrium chamber (6), a pressure gauge (7), a second shutoff valve (8), an airtight chamber (9), a cigarette packet (10), a differential pressure sensor (11) and a computer (12); A non-destructive testing method for the tightness of a cigarette packet according to the present invention. [The present invention 1003] (1) preparing the tank of the equilibrium chamber (6) at a specific vacuum level and closing the second shutoff valve (8) before starting the test; (2) Open the air supply source (1), open the first shutoff valve (5), and slowly turn the pressure regulating valve (2), while the vacuum generating device (3) is operating and the equilibrium chamber (6) generates a negative pressure; continue to turn the pressure regulating valve (2) until the pressure gauge (7) indicates -3500 Pa to -5000 Pa, and after the pointer of the pressure gauge (7) stabilizes, close the first shutoff valve (5), while the negative pressure in the equilibrium chamber (6) is equal to the value indicated by the pressure gauge (7); (3) opening the airtight chamber (9), placing the cigarette packet (10) in the airtight chamber (9), and then closing and sealing the airtight chamber (9); (4) Activating the computer (12), opening the data acquisition software and connecting to the output signal of the micro pressure sensor (11), and setting the data acquisition frequency to 10 Hz; (5) Click on the data acquisition software to start data collection, then immediately open the second shutoff valve (8) and then quickly close it (within 2 to 4 seconds) to obtain the measured pressure value P t when the pressure is stable, stop collecting data, export and store the data, then open the airtight chamber (9) to take out the cigarette packet (10) and complete the sealing degree measurement of the cigarette packet, and if the negative pressure value shown by the pressure gauge 7 is greater than -3500 Pa after successively measuring several sets of cigarette packets (10), repeat step (2); (6) Save the measurement data and calculate the external volume V of the cigarette pack. 1 , the final pressure in the airtight chamber P e , the measured pressure in the airtight chamber P t , time t, and the initial measured pressure P in the airtight chamber t0 Based on the data, the data is calculated using three models to obtain three indicators, namely, the effective air permeability "α" of the cigarette pack, the effective diffusion coefficient "k" of the cigarette pack and the effective leakage area "A" of the cigarette pack, and all the three indicators can independently reflect the sealing degree of the cigarette pack. where the effective air permeability of the cigarette pack "α", the effective diffusion coefficient of the cigarette pack "k" and the effective leakage area of ​​the cigarette pack "A" respectively represent the sealing degree of the cigarette pack, and the larger the value, the worse the sealing degree; A non-destructive testing method for the tightness of a cigarette packet of the present invention 1001 or 1002. [The present invention 1004] In step (6), a data model based on Darcy's law is TIFF0007618559000001.tif25133 where: α: Effective air permeability of the cigarette box (cm / min); A s : Surface area of ​​cigarette pack (m 2 );V 1 : External volume of cigarette pack (m 3 );P 0 : Initial pressure of cigarette box (1.01*10 5 Pa); Pe: Final pressure in the airtight chamber (Pa); P t : Measured pressure in airtight chamber (Pa); P t0 : Initial pressure in airtight chamber (Pa) The non-destructive testing method for the tightness of a cigarette packet of the present invention. [The present invention 1005] In step (6), a data model based on Fick's law of diffusion is TIFF0007618559000002.tif17128 where: k: Effective diffusion coefficient of the cigarette pack (m 2 / sec); L: effective distance (m); V 1 : External volume of cigarette pack (m 3 );P e : Final pressure in the airtight chamber (Pa); P t : Measured pressure in airtight chamber (Pa); P t0 : Initial pressure in airtight chamber (Pa) The non-destructive testing method for the tightness of a cigarette packet of the present invention. [The present invention 1006] In step (6), a data model based on molecular kinetic theory is TIFF0007618559000003.tif17128 where: A: Effective leak area of ​​the cigarette pack (m 2 )、K B : Boltzmann constant (1.38*10 -23 J / K), m: molecular weight (29*1.67*10 -27 kg);V 1 : External volume of cigarette pack (m 3 );P e : Final pressure in the airtight chamber (Pa); P t : Measured pressure in airtight chamber (Pa); P t0 : Initial pressure in airtight chamber (Pa) The non-destructive testing method for the tightness of a cigarette packet of the present invention. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a schematic diagram of a non-destructive testing device for the tightness of cigarette packets. [Diagram 2] FIG. 2 shows the measured Pt-t data and least squares fitting data for the three models. [Figure 3a] FIG. 3a is a comparison diagram of the obtained effective air permeability "α" of the cigarette packets and the results obtained by the conventional measurement method (destructive). [Figure 3b] FIG. 3b shows a comparison of the obtained effective diffusion coefficient "k" of the cigarette packet with the results obtained by the conventional measurement method (destructive). [Figure 3c] FIG. 3c shows a comparison of the obtained effective leakage area "A" of the cigarette packet with the results obtained by the conventional measurement method (destructive). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] The method for non-destructive testing of the tightness of a cigarette packet provided by the present invention will be described in more detail below with reference to the accompanying drawings and specific embodiments thereof.

[0015] The method for non-destructive testing of the tightness of a cigarette packet includes the following steps: placing a cigarette packet to be tested in an airtight chamber and using an equilibrium chamber to rapidly create a stable negative pressure in the airtight chamber; continuing to measure the pressure change in the airtight chamber until equilibrium is reached, and establishing a data model by using Darcy's law, Fick's law of diffusion, and molecular kinetic theory physical process analysis; obtaining three indexes having physical meanings, namely, the effective air permeability of the cigarette pack, the effective diffusion coefficient of the cigarette pack, and the effective leakage area of ​​the cigarette pack, based on the data of the pressure and time of the sealed space, wherein the three indexes can independently reflect different sealing degrees, and the larger the values ​​of these three data are, the worse the sealing degree is.

[0016] As shown in FIG. 1, the test device of the non-destructive testing method for the tightness of a cigarette packet includes a pressure regulating valve 2, a vacuum generating device 3, an equilibrium chamber 6, a pressure gauge 7, an airtight chamber 9, a cigarette packet 10, a minute pressure difference sensor 11 and a computer 12; One end of the vacuum generator 3 is connected to the pressure regulating valve 2, and the other end is connected to the muffler 4; where, the pressure regulating valve 2 is connected to the air supply source 1; The vacuum generating device 3 is connected in sequence to a first shutoff valve 5 , an equilibrium chamber 6 , a pressure gauge 7 , a second shutoff valve 8 , an airtight chamber 9 , a cigarette packet 10 , a differential pressure sensor 11 and a computer 12 .

[0017] The specific implementation steps are as follows: (1) Before starting the test, prepare the tank of the equilibration chamber 6 at a specific vacuum level, open the air supply source 1, and close the second shutoff valve 8. (2) Open the first shutoff valve 5 and slowly twist the pressure regulating valve 2 by hand, while the vacuum generator 3 is operating and the equilibrium chamber 6 generates negative pressure. The function of the muffler 4 is to reduce noise generated when the vacuum generator 3 is operating. Continue twisting the pressure regulating valve 2 until the pressure gauge 7 indicates -3500 Pa to -5000 Pa, and close the first shutoff valve 5 after the pointer of the pressure gauge 7 stabilizes. At this time, the negative pressure in the equilibrium chamber 6 is equal to the value indicated by the pressure gauge 7. (3) Opening the chamber 9 and placing a particular brand of cigarette pack 10 into the chamber 9, then closing and sealing the chamber 9. (4) Activate the computer 12, open the data acquisition software and connect to the output signal of the micro pressure sensor 11, and set the data acquisition frequency to 10 Hz. (5) Click the “Start” button in the data acquisition software to start data collection, then immediately open the second shutoff valve 8 and quickly close it (within 2 to 4 seconds) to obtain the measured pressure value P tWhen the pressure is stable, stop collecting data, export and save the data, then open the airtight chamber 9 to take out the cigarette pack 10 and complete the measurement of the sealing degree of the cigarette pack. If the negative pressure value shown on the pressure gauge 7 is greater than -3500 Pa after measuring several sets of cigarette packs in succession, repeat step (2). (6) Save the measurement data and calculate the external volume V1 (m 3 ), the final pressure in the airtight chamber P e (Pa), measured pressure in the airtight chamber (Pa) ~ time t, initial measured pressure in the airtight chamber P t0 Based on the data such as (Pa), the data are calculated using the formulas of the three models respectively, as shown in FIG.

[0018] The effective air permeability of the cigarette pack, "α" (unit: cm / min, i.e., CU), and the effective diffusion coefficient, "k" (unit: m 2 / sec) and effective leak area "A" (unit: m 2 ) are calculated, and then the sealability of the cigarette packet is obtained.

[0019] The above procedure is repeated to test 10 cigarette packet samples, and the obtained data is compared with a conventional destructive testing method (Chinese patent (publication number: CN 104792470 A)).

[0020] As shown in Figure 3, the results of the conventional destructive test of the tightness of the cigarette pack (expressed as the absolute value of the pressure difference) are plotted against the effective air permeability of the cigarette pack, “α” (Figure 3a) (unit: cm / min, i.e., CU), the effective diffusion coefficient of the cigarette pack, “k” (Figure 3b) (unit: m 2 / sec) and the effective leakage area of ​​the cigarette pack, “A” (Figure 3c) (unit: m 2 ), the data show that the measurement results of the present invention are consistent with the data of the traditional destructive test. The reduction of the three data indexes improves the sealing of the cigarette packet.

[0021] In step (6), the formula based on Darcy's law is: TIFF0007618559000004.tif29147α: effective air permeability of cigarette box (cm / min); A: surface area of ​​cigarette box (m 2 ) ; V1: External volume of the cigarette pack (m 3 );P0: Initial pressure of the cigarette box (1.01*10 5 Pa);P e : Final pressure in the airtight chamber (Pa); P t : Measured pressure in airtight chamber (Pa); P t0 : Initial pressure in the airtight chamber (Pa).

[0022] In step (6), the equation based on Fick's law of diffusion is: TIFF0007618559000005.tif18128k: Effective diffusion coefficient of a cigarette pack (m 2 / sec; L: effective distance (m); V1: external volume of cigarette pack (m 3 );P e : Final pressure in the airtight chamber (Pa); P t : Measured pressure in airtight chamber (Pa); P t0 : Initial pressure in the airtight chamber (Pa).

[0023] In step (6), the equation based on molecular kinetics is: TIFF0007618559000006.tif18128A: Effective leak area of ​​a cigarette pack (m 2 ), K B : Boltzmann constant (1.38*10 -23 J / K), m: molecular weight (29*1.67*10 -27 kg); V1: external volume of the cigarette pack (m 3 );P e : Final pressure in the airtight chamber (Pa); P t : Measured pressure in airtight chamber (Pa); P t0 : Initial pressure in the airtight chamber (Pa).

[0024] Finally, it should be noted that the above embodiments are only used to describe the technical solutions of the present invention, and are not intended to limit the present technical method. The application of the present invention can be extended to other modifications, variations, applications and embodiments, and therefore all such modifications, variations, applications and embodiments are deemed to be within the spirit and teachings of the present invention.

Claims

1. 1. A method for non-destructively testing the tightness of a cigarette packet, comprising the steps of: placing a cigarette packet to be tested in an airtight chamber and using an equilibrium chamber to rapidly create a stable negative pressure in the airtight chamber; Continuing to measure the pressure change in the airtight chamber until equilibrium is reached, and establishing a data model by using Darcy's law, Fick's law of diffusion, and molecular kinetic theory physical process analysis; The data model based on Darcy's law is where: α: Effective air permeability of the cigarette box (cm / min); A s : Surface area of ​​cigarette pack (m 2 );V 1 :External volume of cigarette pack (m 3 ) ;P 0 : Initial pressure of the cigarette box (1.01*10 5 Pa); Pe: Final pressure of the airtight chamber (Pa); P t : Measured pressure in airtight chamber (Pa); P t0 : Initial pressure in the airtight chamber (Pa) and The data model based on Fick's law of diffusion is where: k: Effective diffusion coefficient of the cigarette pack (m 2 / sec); L: Effective distance (m); V 1 :External volume of cigarette pack (m 3 ) ;P e : Final pressure in the airtight chamber (Pa); P t : Measured pressure in airtight chamber (Pa); P t0 : Initial pressure in the airtight chamber (Pa) and The data model based on the molecular kinetic theory is where: A: Effective leak area of ​​the cigarette pack (m 2 ), K B : Boltzmann constant (1.38*10 -23 J / K), m: molecular weight (29*1.67*10 -27 kg);V 1 :External volume of cigarette pack (m 3 ) ;P e : Final pressure in the airtight chamber (Pa); P t : Measured pressure in airtight chamber (Pa); P t0 : Initial pressure in the airtight chamber (Pa) That is, process; obtaining three indexes, namely, effective air permeability "α" of the cigarette pack, effective diffusion coefficient "k" of the cigarette pack, and effective leakage area "A" of the cigarette pack, based on the data of pressure and time of the sealed space, the three indexes reflect different sealing degrees, and the larger the values ​​of these three data are, the worse the sealing degree is.

2. A test device used in the non-destructive test method for the tightness of a cigarette packet includes a pressure regulating valve (2), a vacuum generating device (3), an equilibrium chamber (6), a pressure gauge (7), an airtight chamber (9), a cigarette packet (10), a differential pressure sensor (11) and a computer (12); One end of the vacuum generator (3) is connected to the pressure regulating valve (2) and the other end is connected to the muffler (4); The pressure regulator (2) is connected to the air supply (1), A vacuum generating device (3) is sequentially connected to a first shutoff valve (5), an equilibrium chamber (6), a pressure gauge (7), a second shutoff valve (8), an airtight chamber (9), a cigarette packet (10), a differential pressure sensor (11) and a computer (12); A method for non-destructively testing the tightness of a cigarette packet according to claim 1.

3. (1) preparing the tank of the equilibrium chamber (6) at a specific vacuum level before starting the test and closing the second shutoff valve (8); (2) open the air supply source (1), open the first shutoff valve (5), and slowly turn the pressure regulating valve (2), while the vacuum generating device (3) is working and the equilibrium chamber (6) generates negative pressure; continue to turn the pressure regulating valve (2) until the pressure gauge (7) indicates -3500 Pa to -5000 Pa, and close the first shutoff valve (5) after the pointer of the pressure gauge (7) stabilizes, at which time the negative pressure in the equilibrium chamber (6) is equal to the value indicated by the pressure gauge (7); (3) opening the airtight chamber (9), placing the cigarette packet (10) in the airtight chamber (9), and then closing and sealing the airtight chamber (9); (4) running the computer (12), opening the data acquisition software to connect to the output signal of the differential pressure sensor (11), and setting the data acquisition frequency to 10 Hz; (5) Click the data acquisition software to start data collection, then immediately open the second shutoff valve (8) and then quickly close it within 2 to 4 seconds, and record the measured pressure value P t when the pressure is stable, stop collecting data, export and store the data, then open the airtight chamber (9) to take out the cigarette packet (10) and complete the sealing degree measurement of the cigarette packet, and if the negative pressure value shown on the pressure gauge (7) is greater than -3500 Pa after successively measuring several sets of cigarette packets (10), repeat step (2); (6) Save the measurement data and calculate the external volume V of the cigarette pack. 1 , the final pressure in the airtight chamber P e , the measured pressure in the airtight chamber P t , time t, and the initial measured pressure P in the airtight chamber t0 Based on the data, calculate the data using three models to obtain three indicators, namely, the effective air permeability "α" of the cigarette pack, the effective diffusion coefficient "k" of the cigarette pack and the effective leakage area "A" of the cigarette pack, and all the three indicators can independently reflect the sealing degree of the cigarette pack. where the effective air permeability of the cigarette pack "α", the effective diffusion coefficient of the cigarette pack "k" and the effective leakage area of ​​the cigarette pack "A" respectively represent the sealing degree of the cigarette pack, and the larger the value, the worse the sealing degree; A method for non-destructively testing the tightness of a cigarette packet according to claim 1 or 2.

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