US 11,927,504 B2
Non-destructive testing method for tightness degree of small cigarette box packaging
Bin Li, Zhengzhou (CN); Yue Sun, Zhengzhou (CN); Le Wang, Zhengzhou (CN); Guangyang Qiu, Zhengzhou (CN); Mingjian Zhang, Zhengzhou (CN); Ran Chen, Zhengzhou (CN); Ke Zhang, Zhengzhou (CN); and Nan Deng, Zhengzhou (CN)
Assigned to ZHENGZHOU TOBACCO RESEARCH INSTITUTE OF CNTC, Zhengzhou (CN)
Appl. No. 17/418,726
Filed by ZHENGZHOU TOBACCO RESEARCH INSTITUTE OF CNTC, Zhengzhou (CN)
PCT Filed Jul. 22, 2020, PCT No. PCT/CN2020/103435
§ 371(c)(1), (2) Date Jun. 25, 2021,
PCT Pub. No. WO2021/036593, PCT Pub. Date Mar. 4, 2021.
Claims priority of application No. 201910788793.0 (CN), filed on Aug. 26, 2019.
Prior Publication US 2022/0065733 A1, Mar. 3, 2022
Int. Cl. G01M 3/32 (2006.01)
CPC G01M 3/32 (2013.01) 6 Claims
OG exemplary drawing
 
1. A non-destructive determination method of a cigarette packet's seal, the method comprising:
placing a cigarette packet to be tested in an airtight chamber, and quickly forming a stable negative pressure in the airtight chamber by using a balance cabin;
continuously measuring the pressure change in the airtight chamber until it reaches equilibrium, and establishing a data model by analyzing Darcy's law, Fick's law of diffusion and a physical process of kinetic molecular theory;
wherein, the Darcy's law is:

OG Complex Work Unit Math
α: effective air permeability of cigarette packet (cm/min); As: surface area of cigarette packet (m2); V1: external volume of cigarette packet (m3); P0: initial pressure of cigarette packet (1.01*105 Pa); Pe: final pressure of the airtight chamber (Pa); Pt: measured pressure of the airtight chamber (Pa); Pt0: initial pressure (Pa) of the airtight chamber;
the Fick's law of diffusion is:

OG Complex Work Unit Math
k: effective diffusion coefficient of cigarette packet (m2/s); L: effective distance (m); V1: the external volume of cigarette packet (m3); Pe: the final pressure of airtight chamber (Pa); Pt: the measured pressure of the airtight chamber (Pa); Pt0: the initial pressure of the airtight chamber (Pa); and
the kinetic molecular theory is:

OG Complex Work Unit Math
A: effective leakage area of cigarette packet (m2), KB: Boltzmann constant (1.38*10−23 J/K), m: molecular mass (29*1.67*10−27 kg); V1: the external volume of cigarette packet (m3); Pe: the final pressure of the airtight chamber (Pa); Pt: the measured pressure of the airtight chamber (Pa); Pt0: the initial pressure of the airtight chamber (Pa);
obtaining/collecting the data of the pressure and time of a sealed space; and
determining following three indicators: an effective air permeability of cigarette packet “a”, an effective diffusion coefficient of cigarette packet “k” and an effective leakage area of cigarette packet “A” based on the data of the collected pressure and time of the sealed space; the three indicators can independently reflect different seal, the larger the three indicators, the worse the seal.