Patent ID: 11927504
Assignee: ZHENGZHOU TOBACCO RESEARCH INSTITUTE OF CNTC
Field: Measurement (Instruments)
Classification: CPC G | IPC G

Claim 2:
3. The non-destructive determination method of a cigarette packet's seal according to claim 2, wherein:
(1 before testing, preparing a tank of the balance cabin (6) with a certain degree of vacuum, and closing the second shut-off valve (8);
(2 opening the air supply (1), opening the first shut-off valve (5), and slowly screwing the pressure regulating valve (2), meanwhile the vacuum generator (3) works and the balance cabin (6) generates negative pressure; continuing to rotate the pressure regulating valve (2) to make the pressure gauge (7) display between −3500 Pa and −5000 Pa, after a pointer of the pressure gauge (7) is stable, closing the first shut-off valve (5), and at this time, the negative pressure of the balance cabin (6) is equal to the value indicated on 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 starting the computer (12), opening a data acquisition software and connecting it to an output signal of a micro-pressure sensor (11), and setting a frequency of the acquired data to 10 Hz;
(5 clicking the data acquisition software to collect data, and then immediately opening the second shut-off valve (8) and then quickly closing it in 2 s˜4 s, when the measured pressure value Pt is stable, stopping collecting data, exporting and saving the data, and then opening the airtight chamber (9) and taking out the cigarette packet (10), completing the seal measurement of the cigarette packet, and continuously measuring several groups of cigarette packets (10), when the negative pressure value indicated on the pressure gauge (7) is greater than −3500 Pa, repeating step (2; and
(6 saving the measurement data, the data are calculated using the three models according to the external volume V1 of cigarette packet, the final pressure Pe of the airtight chamber, the measured pressure Pt of the airtight chamber, the time t, and the initial pressure Pt0 of the airtight chamber, to obtain the three indicators: 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 the three indicators can independently reflect the seal of the cigarette packets,
among the three indicators, the effective air permeability of cigarette packet “α”, 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.