NON-DESTRUCTIVE TESTING METHOD FOR TIGHTNESS DEGREE OF SMALL CIGARETTE BOX PACKAGING

Abstract

The application proposes a non-destructive testing method for the sealing degree of the small cigarette box packaging, which includes placing the small cigarette box to be tested in an airtight chamber, using a balance cabin to quickly form a stable negative pressure in the airtight chamber; The pressure change of the sealed chamber is continuously measured until equilibrium, and the data model is analyzed and established by using Darcy's law, Fick's diffusion law and the physical process of molecular kinetic theory. Through the non-destructive testing method for the sealing degree of the small cigarette box packaging of the present invention, the traditional destructive measurement (damaged small box packaging) for measuring the sealing degree of cigarette small box is changed into non-destructive testing; The test results have specific physical meaning; The test time of a single sample is reduced to ⅕ of the time of destructive test.

Claims

1. A non-destructive determination of cigarette packet's seal, includes: Placing the cigarette packet under test in an airtight chamber, and use the balance cabin to make the airtight chamber quickly form a stable negative pressure; Continuing to measure the pressure change in the airtight chamber until it reaches equilibrium, and using Darcy's law, Fick's law of diffusion and the physical process of kinetic molecular theory to analyze and establish a data model; Based on the data of the pressure and time of the sealed space, three indicators of physical significance of the effective air permeability of cigarette packet “a”, the effective diffusion coefficient of cigarette packet “k” and the effective leakage area of cigarette packet “A” are obtained. The three indicators can independently reflect different seal. The larger the three data values, the worse the seal.

2. The non-destructive determination of cigarette packet's seal according to claim 1, wherein: The testing device used in the non-destructive determination of cigarette packet's seal includes: a pressure regulating valve (2), a vacuum generator (3), a balance cabin (6), a pressure gauge (7), and an airtight chamber (9).), cigarette packet (10), differential pressure sensor (11) and computer (12); One end of the vacuum generator (3) is connected with a pressure regulating valve (2), and the other end is connected with a muffler (4); The pressure regulating valve (2) connected to the air supply (1); and The vacuum generator (3) is sequentially connected to the first shut-off valve (5), the balance cabin (6), the pressure gauge (7), the second shut-off valve (8), the airtight chamber (9), and the cigarette packet (10), differential pressure sensor (11) and computer (12).

3. The non-destructive determination of cigarette packet's seal according to claim 1, wherein: (1 Before starting the test, prepare a tank with a certain vacuum degree of balance chamber (6), and close the second shut-off valve (8); (2 Turn on the air supply (1), open the first shut-off valve (5), and slowly screw the pressure regulating valve (2). At this time, the vacuum generator (3) works and the balance cabin (6) produces negative pressure; continue to rotate the pressure regulating valve (2) to make the pressure gauge (7) display between −3500 Pa and −5000 Pa. After the pointer of the pressure gauge (7) is stable, close the first shut-off valve (5). At the time, the balance cabin (6) The negative pressure is equal to the value shown on the pressure gauge (7); (3 Open the airtight chamber (9), place the cigarette packet (10) in the airtight room (9), and then close and seal the airtight room (9); (4 Start 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 data acquisition software to collect data, and then immediately open the second shut-off valve (8) and then quickly close it (in 2 s˜4 s). When the measured pressure value P.sub.t is stable, stop collecting data, export and save the data, and then open the measurement room (9) and take out the cigarette packet (10). Complete the seal measurement of the cigarette packet, and continuously measure several sets of cigarette packets (10). When the negative pressure value shown on the pressure gauge 7 is greater than −3500 Pa, repeat step (2; and (6 Save the measurement data. According to the external volume V.sub.1 of cigarette packet, the final pressure P.sub.e of the airtight chamber, the measured pressure P.sub.t of the airtight chamber, the time t, the initial measured pressure P.sub.t0 of the airtight chamber, etc., the data are calculated using the three models to obtain the three indicators of the effective air permeability of cigarette packet “a”, the effective diffusion coefficient of cigarette packet “k” and the effective leakage area of cigarette packet “A”. All three indicators can independently reflect the seal of the cigarette packets. Among them, the effective air permeability of cigarette packet “a”, the effective diffusion coefficient of cigarette packet “k” and the effective leakage area of cigarette packet “A” respectively represent the seal of the cigarette packets. The larger the value, the worse the seal.

4. The non-destructive determination of cigarette packet's seal according to claim 1, wherein: In step (6, the above is based on Darcy's law: $p_t=\frac{-p_{t0}.Math.\left(p_e+P_0\right)}{-p_e-\frac{p_e-p_{t0}}{\begin{array}{c}-\frac{p_{t0}}{P_0}.Math.\\ \exp \left(-1.67\times {10}^{-7}.Math.\alpha .Math.\frac{-p_{t0}.Math.\left(p_e+P_0\right)}{p_e-p_{t0}}.Math.\frac{A}{V_1}.Math.t\right)-1\end{array}}}-P_0$ a: the effective air permeability of cigarette packet (cm/min); A.sub.s: the surface area of cigarette packet (m.sup.2); the external volume of cigarette packet (m.sup.3); P.sub.0: the initial pressure of cigarette packet (1.01*10.sup.5 Pa); Pe: the final pressure of the airtight chamber (Pa); P.sub.t: the measured pressure of the airtight chamber (Pa); P.sub.t0: the initial pressure (Pa) of the airtight chamber.

5. The non-destructive determination of cigarette packet's seal according to claim 1, wherein: In step (6, the above is based on Fick's law of diffusion: $p_t=p_e+\left(p_{t0}-p_e\right).Math.\exp \left[-\frac{p_{t0}}{\left(p_{t0}-p_e\right).Math.V_1}.Math.L.Math.k.Math.t\right]$ k: effective diffusion coefficient of cigarette packet (m.sup.2/s); L: effective distance (m); V.sub.1: external volume of cigarette packet (m.sup.3); P.sub.e: final pressure of airtight chamber (Pa); P.sub.t: measured pressure of airtight chamber (Pa); P.sub.t0: the initial pressure of the airtight chamber (Pa).

6. The non-destructive determination of cigarette packet's seal according to claim 1, wherein: In step (6, the above is based on the molecular kinetic theory: $p_t=p_e+\left(p_{t0}-p_e\right).Math.\exp \left[-\frac{\sqrt{K_{B}T}}{\sqrt{2\pi .Math.m}}.Math.A.Math.\frac{p_{t0}}{\left(p_{t0}-p_e\right).Math.V_1}.Math.t\right]$ A: Effective leakage area of cigarette packet (m.sup.2), K.sub.B: Boltzmann constant (1.38*10.sup.−23 J/K), m: molecular mass (29*1.67*10.sup.−27 kg); external volume of cigarette packet (m.sup.3); P.sub.e: the final pressure of the airtight chamber (Pa); P.sub.t: the measured pressure of the airtight chamber (Pa); P.sub.t0: the initial pressure of the airtight chamber (Pa).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] FIG. 1 shows a schematic diagram of a non-destructive testing device for the seal of cigarette packet.

[0026] FIG. 2 shows the measured data P.sub.t-t data and the least square fitting data diagram of the three models.

[0027] FIG. 3a shows a comparison diagram of the obtained cigarette packet's effective air permeability “a” and the result obtained by the traditional measurement method (destructive).

[0028] FIG. 3b shows a comparison diagram of the obtained effective diffusion coefficient “k” and the result obtained by the traditional measurement method (destructive).

[0029] FIG. 3c shows the comparison between the obtained effective leakage area “A” of cigarette packet and the result obtained by the traditional measurement method (destructive).

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] The following describes in further detail a method for non-destructive determination of cigarette packet's seal provided by the present invention with reference to the accompanying drawings and specific embodiments thereof.

[0031] A method for nondestructive determination of cigarette packet's seal, which includes placing the tested cigarette packets in an airtight chamber, and make use of a balance cabin body to quickly form a stable negative pressure in the airtight chamber;

[0032] Continue to measure the pressure change in the sealed chamber until it reaches equilibrium, and use Darcy's law, Fick's law of diffusion and the physical process of kinetic molecular theory to analyze and establish a data model;

[0033] Based on the data of the pressure and time of the sealed space, three indicators of physical significance of the effective air permeability of cigarette packet, the effective diffusion coefficient of cigarette packet g and the effective leakage area of cigarette packet are obtained. The three indicators can independently reflect different seal. The larger the three data values, the worse the seal.

[0034] As shown in FIG. 1, the detection device of the nondestructive determination of cigarette packet's seal includes the pressure regulating valve 2, the vacuum generator 3, the balance chamber 6, the pressure gauge 7, the airtight chamber 9 the cigarette packet 10, and the micro pressure Difference sensor 11 and computer 12,

[0035] One end of the vacuum generator 3 is connected to a pressure regulating valve 2, and the other end is connected to a muffler 4; wherein, the pressure regulating valve 2 is connected to the air source 1;

[0036] The vacuum generator 3 is connected to the first shut-off valve 5, the balance cabin 6, the pressure gauge 7, the second shut-off valve 8, the airtight chamber 9, the cigarette packet 10, the differential pressure sensor 11 and the computer 12 in sequence.

[0037] The specific implementation steps are as follows:

[0038] (1 Before starting the test, prepare a tank of balance chamber 6 with a certain degree of vacuum. Open the air supply 1, and close the second shut-off valve 8.

[0039] (2 Open the first shut-off valve 5, and slowly screw the pressure regulating valve 2 by hand. At this time, the vacuum generator 3 works and the balance cabin 6 produces negative pressure. The function of the muffler 4 is to reduce the noise generated when the vacuum generator 3 is working. Continue to screw the pressure regulating valve 2 to make the pressure gauge 7 display between −3500 Pa and −5000 Pa. After the pointer of the pressure gauge 7 is stable, close the first shut-off valve 5. At this time, the negative pressure of the balance cabin 6 is equal to the value shown in the pressure gauge 7.

[0040] (3 Open the airtight chamber 9, place a cigarette pack 10 of a certain brand in the airtight chamber 9, and then close and seal the airtight chamber 9.

[0041] (4 Start 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.

[0042] (5 Click the “Start” button of the data acquisition software to start collecting data, then immediately open the second shut-off valve 8, then quickly close it (in 2 s˜4 s), When the measured pressure value Pt is stable, stop collecting the data, export and save the data, and then open the airtight chamber 9 and take out the cigarette pack 10, and completes the seal measurement of cigarette packet. After continuously measuring several sets of cigarette pack, repeat step (2) when the negative pressure value shown on the pressure gauge 7 is greater than −3500 Pa .

[0043] (6 Save the measurement data. According to the data, such as the external volume of the cigarette packet V.sub.1(m.sup.3), the final pressure of the airtight chamber P.sub.e (Pa), the measured pressure of the airtight chamber (Pa)˜time t, the initial measured pressure of the airtight chamber P.sub.t0 (Pa), utilize the formulas of the three models to calculate the data respectively, as shown in FIG. 2.

[0044] The three indicators, which are the effective air permeability “a” (unit: cm/min, i.e. CU), the effective diffusion coefficient “k” (unit: m.sup.2/s) and the effective leakage area “A” (unit: m.sup.2) of the cigarette pack, are calculated, then the seal of cigarette packet is obtained.

[0045] Repeat the above operation to test 10 cigarette packet samples, and compare the data obtained with the traditional destructive testing method (CN Patent (Publication No.: CN' 104792470 A)).

[0046] Comparing the results of traditional destructive test of cigarette packet's seal (indicated by the absolute value of the pressure difference) with the three indicators of the effective air permeability of cigarette packet “a” (FIG. 3a) (unit: cm/min, namely CU), the effective diffusion coefficient of cigarette packet “k” (FIG. 3b) (unit: m.sup.2/s) and the effective leakage area of cigarette packet “A” (FIG. 3c) (unit: m.sup.2) as shown in FIG. 3, the data shows that the measurement results of the invention are in line with the traditional destructive testing data. With the reduction of the three data. indicators, the seal of the cigarette packet improves.

[0047] Step (6, based on Darcy's law:

[00001]$p_t=\frac{-p_{t0}.Math.\left(p_e+P_0\right)}{-p_e-\frac{p_e-p_{t0}}{\begin{array}{c}-\frac{p_{t0}}{P_0}.Math.\\ \exp \left(-1.67\times {10}^{-7}.Math.\alpha .Math.\frac{-p_{t0}.Math.\left(p_e+P_0\right)}{p_e-p_{t0}}.Math.\frac{A}{V_1}.Math.t\right)-1\end{array}}}-P_0$

[0048] a: the effective air permeability of cigarette packet (cm/min); A: the surface area of cigarette packet (m.sup.2); V.sub.1: the external volume of cigarette packet (m.sup.3); P.sub.0: the initial pressure of cigarette packet (1.01*10.sup.5 Pa); P.sub.e: the final pressure of the airtight chamber (Pa); P.sub.t: the measured pressure of the airtight chamber (Pa); P.sub.t0: the initial pressure (Pa) of the airtight chamber.

[0049] Step (6, based on Fick's law of diffusion:

[00002]$p_t=p_e+\left(p_{t0}-p_e\right).Math.\exp \left[-\frac{p_{t0}}{\left(p_{t0}-p_e\right).Math.V_1}.Math.L.Math.k.Math.t\right]$

[0050] k: effective diffusion coefficient of cigarette packet (m.sup.2/s); L: effective distance (m); V.sub.1: external volume of cigarette packet (m.sup.3); P.sub.e: final pressure of airtight chamber (Pa), P.sub.t: measured pressure of airtight chamber (Pa), P.sub.t0: the initial pressure of the airtight chamber (Pa).

[0051] Step (6, based on kinetic molecular theory:

[00003]$p_t=p_e+\left(p_{t0}-p_e\right).Math.\exp \left[-\frac{\sqrt{K_{B}T}}{\sqrt{2\pi .Math.m}}.Math.A.Math.\frac{p_{t0}}{\left(p_{t0}-p_e\right).Math.V_1}.Math.t\right]$

[0052] A: Effective leakage area of cigarette packet (m.sup.2), K.sub.B: Boltzmann constant (1.38*10.sup.−23J/K), m: molecular mass (29*1.67*10.sup.−27kg); V1: external volume of cigarette packet (m.sup.3); P.sub.e: the final pressure of the airtight chamber (Pa); P.sub.t: the measured pressure of the airtight chamber (Pa); P.sub.t0: the initial pressure of the airtight chamber (Pa).

[0053] At last, it should be noted that the above embodiments are only used to describe the technical solutions of the present invention and not to limit the present technical methods. The application of the present invention can be extended to other modifications, changes, applications and embodiments, and therefore it is considered all such modifications, changes, applications, and embodiments are all within the spirit and teaching scope of the present invention.