Device for nondestructively detecting packaging tightness of pre-packaged product by adopting dynamic differential pressure

Abstract

The utility model discloses a device for nondestructively detecting the packaging tightness of a pre-packaged product by adopting dynamic differential pressure. The device comprises a sealed cabin (1), a negative pressure suction unit (2), a differential pressure sensor (4), a data recorder (5) and a shaped box body model (6), the suction capacity and speed of the negative pressure suction unit (2) are adjustable; and a connecting pipeline (3) is arranged between the sealed cabin (1) and the negative pressure suction unit (2). According to the utility model, the test sealed cabin (1) is of a piston-like structure of which the progress and the suction speed can be regulated and controlled, so that the flexibility and the accuracy of the packaging tightness test of the pre-packaged product are greatly improved, and the negative pressure response is quicker and more accurate due to the piston-like structure design. According to the device for nondestructively detecting the packaging tightness of the pre-packaged product by adopting the dynamic differential pressure, the requirements on the opening and closing mode and space of a system are reduced, and the stability and efficiency of the test are also improved.

Description

Technical Field

[0001] The utility model relates to the technical field of detecting the packaging tightness of soft and hard pre-packaged products. Specifically, it relates to a device for non-destructively detecting the packaging tightness of pre-packaged products by using dynamic pressure difference. Background Technique

[0002] At present, there are many testing methods for the packaging tightness of food, medicine and other pre-packaged products represented by cigarettes at home and abroad, mainly covering vacuum attenuation method, bubble test method, tracer marking method, high-voltage discharge method, microbial immersion method, etc. The existing detection methods mostly evaluate the differences in macroscopic state parameters of products under enhanced leakage conditions. The vacuum attenuation method uses the pressure difference feedback under test-limited conditions to represent the packaging tightness. As a common testing method for packaging tightness, it is widely used in the fields of food, medicine and other packaging.

[0003] For example, ASTM F2338-09(2020) of the American Society for Testing and Materials and T / CNFIA 177-2023, a testing method for food packaging tightness jointly formulated by many enterprises in China's food and packaging industry, are both based on this, using the vacuum attenuation method for non-destructive leak detection testing, but the recorded results are all the pressure differences representing the leakage state parameters. In the tobacco industry, YQ-JY / T 2-2018 adopts the "negative pressure air extraction - water immersion method" by placing the punched cigarette small box in a closed measurement chamber to carry out the test of characterizing the sealing degree of the cigarette small box by the instrument pressure difference.

[0004] The bubble method is an intuitive testing method for packaging tightness. During the operation process, the sample needs to be immersed in the test solution, resulting in the total loss of the test sample. For example, the standard method GB / T 15171-1994 for testing the packaging tightness of food uses the water inspection bubble method. The position where the bubbles emerge can accurately indicate the position of the leakage point, but the sensitivity of this method is not high. Similarly, when determining the leakage point in YQ-JY / T2-2018, an appropriate amount of water is injected into the measurement chamber to immerse the cigarette small box in water, and the position where the bubbles are generated during the test is the leakage point.

[0005] The tracer marking method for determining the packaging tightness mainly shows that colored water is used as the test solution, and the packaging is directly immersed in the colored water or the colored water is injected into the packaging, and the packaging tightness is determined by comparing the internal and external dyeing of the packaging. ASTM D4991-07(2023), JIS Z0382-1981, ZBC 08003-1987 and GB / T 15171-1994 have all proposed testing methods using test solutions that can mark leakage traces to represent the packaging tightness. In addition to the tracer liquid, usually tracer gas can be filled inside the packaging to monitor its leakage situation and represent its packaging tightness.

[0006] The high-voltage discharge method uses the method of high-frequency high-voltage dielectric barrier discharge to collect the packaging discharge signal. After denoising, the characteristic parameters are extracted respectively under the conditions of intact packaging film and the presence of pinholes.

[0007] On the premise of not damaging the original packaging products, it is of great significance to explore the numerical simulation of packaging sealability from the microphysical process of gas movement. At present, in the non-destructive method, instantaneous vacuum is formed. Generally, a rapid gas flow process forms negative pressure. In this process, high requirements are imposed on the space and the opening and closing methods of the system. In inventions such as CN201910788793.0, ZL202010318808.X, and ZL202010319660.1, a negative pressure generator is involved to form a vacuum environment in the test chamber, and the system error is weakened through simulation parts, interpolation methods, etc. However, there are disadvantages such as complex operation, poor repeatability, and great difficulty in realizing automation, which cannot meet the requirements of data element collection and delivery in the "digital" factory from the production manufacturing line.

[0008] Therefore, to solve the above problems, the present utility model is proposed. Summary of the Utility Model

[0009] The purpose of the present utility model is to address the deficiencies of the prior art and relate to a device for non-destructively detecting the packaging sealability of pre-packaged products using dynamic differential pressure, and at the same time a method for testing the sealing performance of a shaped packaging box body. The test sealing chamber 1 of the present utility model is directly connected to the negative pressure suction unit 2 through a connecting pipe 3, and the suction capacity and speed of the negative pressure suction unit 2 are adjustable. The test sealing chamber 1 of the present utility model is a piston-like structure with adjustable process and suction speed, which greatly improves the flexibility and accuracy of the test of the packaging sealability of pre-packaged products. Coupled with the piston-like structure design, the negative pressure response is faster and more accurate.

[0010] In order to achieve the above object, the technical solution adopted by the present utility model is:

[0011] The first aspect of the present utility model provides a device for non-destructively detecting the packaging sealability of pre-packaged products using dynamic differential pressure, which includes a sealing chamber 1, a negative pressure suction unit 2, a differential pressure sensor 4, a data recorder 5, and a shaped box body model 6;

[0012] The sealing chamber 1 is used to accommodate the shaped box body model 6 and the pre-packaged product to be tested;

[0013] The negative pressure suction unit 2 has at least one air flow channel for completing the suction action, and the suction capacity and speed of the negative pressure suction unit 2 are adjustable;

[0014] There is a connecting pipe 3 between the sealed chamber 1 and the negative pressure suction unit 2, which is used to connect the sealed chamber 1 and the negative pressure suction unit 2 with adjustable speed, so that the sealed chamber 1 and the negative pressure suction unit 2 are in air flow communication;

[0015] The three-dimensional structural dimensions of the shaped box model 6 are the same as those of the pre-packaged product to be tested, and the shaped box model 6 can assume the true sealing performance of the pre-packaged product to be tested.

[0016] Preferably, the sealed chamber 1 has at least one opening for storing the cavity of the shaped box to be tested, and the opening can be manually or automatically sealed during detection, and the sealing degree meets the test requirements.

[0017] Preferably, the adjustment of the suction capacity and speed of the negative pressure suction unit 2 can be achieved through an external automation device or control equipment.

[0018] Preferably, the detection end of the differential pressure sensor 4 can be connected to the inside of the sealed chamber 1 or the inside of the connecting pipe 3. Preferably, the detection end of the differential pressure sensor 4 is connected to the inside of the sealed chamber 1.

[0019] Preferably, the data acquisition end of the data recorder 5 is connected to the data output end of the differential pressure sensor 4. The data recorder 5 is used to collect and record the differential pressure data during the test, and the data acquisition frequency is not less than 1 Hz, preferably 10 Hz to 1000 Hz.

[0020] Preferably, the true sealing performance can be assumed, which is characterized by the packaging leakage area S of the pre-packaged product. The leakage area is analyzed based on the differential pressure curve obtained from the sample test, combined with the test results of the shaped box with assumed true sealing performance and the physical process of gas leakage, and obtained using a mathematical model.

[0021] Preferably, according to the differences of the pre-packaged products to be tested, the shaped box model 6 includes multiple groups.

[0022] Preferably, for the same pre-packaged product to be tested, at least two shaped box models 6 are prepared. One has an assumed true sealing performance of no leakage (extremely high sealing degree, leakage area on the box body is 0), and the other has an assumed true sealing performance slightly lower than that of all the tested boxes (extremely low sealing degree, leakage area on the box body is X). Preferably, multiple shaped box models 6 with the same size of the tested samples and assumed true sealing performance can be set according to the leakage area distribution of the shaped boxes.

[0023] The second aspect of the utility model provides a method for non-destructively testing the sealing degree of pre-packaged products by using dynamic pressure difference. The method for non-destructively testing the sealing degree of pre-packaged products by using dynamic pressure difference is as follows: measuring the three-dimensional structure of the box body to be tested, preparing a plurality of shaped box body models 6 which are consistent with the specifications and dimensions of the sample to be tested and can assume true sealing performance, assuming that the true value can be measured by physical methods to measure the leakage area thereof, and recorded as: S1, S2, S3, ..., Sn; setting the total suction volume and suction time or the suction speed or the suction time of the negative pressure suction unit 2 with adjustable speed; placing a plurality of shaped box body models 6 in turn into the sealed cabin 1 accommodating the shaped box body, and ensuring that the sealed cabin 1 is completely sealed before testing, starting the negative pressure suction unit 2 with adjustable speed to suction, recording the pressure difference change of the sealed cabin 1 during the suction process, and calculating the pressure difference change rate.

[0024] Repeat the above operation using different shaped box models 6 to calculate the pressure difference change rate; establish a related mathematical model between the pressure difference change rate obtained by testing and calculation and the assumed true value of the above shaped box model 6, and this mathematical model is the operating equation for detecting the sealing performance (leakage area).

[0025] Place the shaped box body to be tested into the sealed cabin 1 accommodating the shaped box body, repeat the above-mentioned detection operation process, or the pressure difference change during the suction process, calculate the pressure difference change rate, substitute the pressure difference change rate into the above-mentioned operation equation for detecting the sealing performance, calculate and obtain the sealing performance (leakage area) of the shaped box body to be tested, and complete one detection.

[0026] The method for nondestructively testing the sealing degree of pre-packaged products by using dynamic pressure difference comprises the following steps:

[0027] Step 1: Measure the three-dimensional structural dimensions of the pre-packaged product to be tested, prepare a number of shaped box models 6 that are consistent with the three-dimensional structural dimensions of the pre-packaged product to be tested and can assume real sealing performance, and measure the leakage area by physical methods assuming real sealing performance, and record it;

[0028] Step 2: setting the total suction volume and suction time of the negative pressure suction unit 2; placing one of the shaped box models 6 into the sealed cabin 1 containing the shaped box in turn, and sealing it before testing, starting the negative pressure suction unit 2 to suction, and recording the pressure difference change (Pi~t) during the suction process;

[0029] Step 3: Repeat step 2 using different shaped box models 6 to obtain pressure difference variation curves of several shaped box models 6;

[0030] Step 4: Obtain the differential pressure change rate of each shaped box body model 6 from the differential pressure change curves of several shaped box body models 6 in Step 3, and further plot the relationship curve between the differential pressure change rate of the shaped box body model 6 and its leakage area S;

[0031] Step 5: Based on the relationship curve between the differential pressure change rate of the shaped box body model 6 and its leakage area S in Step 4, establish a relevant mathematical model S = F(f(Pi~t)), and this mathematical model is the operation equation for detecting the packaging leakage area of pre-packaged products;

[0032] Step 6: Place the pre-packaged product to be tested into the sealing chamber 1, repeat the detection operation process in Step 2 above, record the differential pressure change (Pi~t) during the suction process, calculate the differential pressure change rate f(Pi~t), substitute the differential pressure change rate into the operation equation for detecting the sealing performance obtained in Step 5 above, calculate the leakage area S of the pre-packaged product to be tested, and thus complete one detection. This leakage area S characterizes the sealing degree of the pre-packaged product to be tested.

[0033] Preferably, the total suction volume and suction time of the negative pressure suction unit 2 in Step 2 are adjusted according to the different sealing properties of the pre-packaged products to be tested.

[0034] Compared with the prior art, the present utility model has the following beneficial effects:

[0035] 1. For the devices for non-destructively detecting the packaging sealing degree of pre-packaged products in the prior art, they all first use a negative pressure generator to form a vacuum environment in the test chamber and then conduct detection. This method requires the formation of instantaneous vacuum, and in this process, there are relatively high requirements for the space and the opening and closing mode of the system. The test sealing chamber 1 of the present utility model is directly connected to the negative pressure suction unit 2 through the connecting pipe 3, and the suction capacity and speed of the negative pressure suction unit 2 are adjustable. The test sealing chamber 1 of the present utility model is a piston-like structure with adjustable process and suction speed, which greatly improves the flexibility and accuracy of the test for the packaging sealing degree of pre-packaged products. Coupled with the piston-like structure design, the negative pressure response is faster and more accurate. Generally speaking, the device for non-destructively detecting the packaging sealing degree of pre-packaged products using dynamic differential pressure of the present utility model not only reduces the requirements for the opening and closing mode of the system and the space, but also improves the stability and efficiency of the test.

[0036] 2. The present utility model innovatively proposes to use a group of shaped box body models 6 for measuring the packaging sealing degree of pre-packaged products. First, obtain the differential pressure change rate of the shaped box body model 6 through test calculation, then establish an operation equation using the differential pressure change rate and the assumed true value leakage area of the shaped box body model 6, and finally obtain the leakage area of the pre-packaged product to be tested by measuring the differential pressure change rate of the pre-packaged product to be tested. The measurement method is simple, accurate and efficient. Description of the Drawings

[0037] Figure 1 It is a schematic diagram of a device for non-destructively detecting the sealing performance of a box-shaped package in an embodiment of the utility model patent.

[0038] Figure 2 It is the differential pressure change data of a box-shaped model with the same appearance as the sample to be measured and assumable true sealing performance in an embodiment of the utility model patent.

[0039] Figure 3 It is the operation equation in an embodiment of the utility model patent.

[0040] Figure 4 It is the differential pressure change data of the test sample in an embodiment of the utility model patent.

[0041] Names of reference numerals in the description of the drawings: 1 - Sealing chamber, 2 - Negative pressure suction unit, 3 - Connecting pipe, 4 - Differential pressure sensor, 5 - Data recorder, 6 - Box-shaped model. Detailed implementation manners

[0042] The following further describes the present utility model in detail with reference to the embodiments.

[0043] Those skilled in the art will understand that the following embodiments are only used to illustrate the present utility model and should not be construed as limiting the scope of the present utility model. For those not specified in the embodiments in terms of specific technologies or conditions, they shall be carried out according to the technologies or conditions described in the literature in this field or according to the product instructions. For those materials or equipment not specified in terms of the manufacturer, they are all conventional products that can be obtained by purchase.

[0044] Those skilled in the art of the present technology can understand that unless specifically stated, the singular forms "a", "an", "the" and "said" used herein may also include the plural forms. It should be further understood that the term "comprising" used in the description of the present utility model means the presence of the described features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or their groups. It should be understood that when we say an element is "connected" to another element, it can be directly connected to other elements, or there may also be intermediate elements. In addition, the "connection" used herein may include wireless connection.

[0045] In the description of the present utility model, unless otherwise specified, the meaning of "a plurality of" is two or more. The orientation or state relationship indicated by terms such as "inside", "above", "below", etc. is based on the orientation or state relationship shown in the drawings, and is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be construed as a limitation to the present utility model.

[0046] In the description of the present utility model, it should be noted that unless otherwise clearly specified and defined, the terms "installation", "connection", and "provided with" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0047] Those skilled in the art of the present technology can understand that unless otherwise defined, all terms used herein, including technical terms and scientific terms, have the same meaning as the general understanding of those of ordinary skill in the art to which the present utility model belongs. It should also be understood that terms such as those defined in a general dictionary should be understood to have a meaning consistent with the meaning in the context of the prior art, and will not be interpreted with an idealized or overly formal meaning unless defined as here.

[0048] Embodiment

[0049] The technical solution of the present utility model will be further described in detail below through specific embodiments.

[0050] As Figure 1 shown, a device for non-destructively detecting the packaging seal of pre-packaged products by dynamic pressure difference includes a sealed chamber 1, a negative pressure suction unit 2, a pressure difference sensor 4, a data recorder 5, and a shaped box model 6;

[0051] The sealed chamber 1 is used to accommodate the shaped box model 6 and the pre-packaged product to be tested;

[0052] The negative pressure suction unit 2 has at least one air flow channel for completing the suction action, and the suction capacity and speed of the negative pressure suction unit 2 are adjustable;

[0053] A connecting pipe 3 is provided between the sealed chamber 1 and the negative pressure suction unit 2 for connecting the sealed chamber 1 and the negative pressure suction unit 2 with adjustable speed, so that the sealed chamber 1 and the negative pressure suction unit 2 form an air flow connection;

[0054] The three-dimensional structure size of the shaped box model 6 is the same as that of the pre-packaged product to be tested, and the shaped box model 6 can assume the true sealing performance of the pre-packaged product to be tested.

[0055] The sealed chamber 1 has at least one opening for storing the cavity of the shaped box to be tested, and the opening can be manually or automatically sealed during the test, and the sealing degree meets the test requirements.

[0056] The suction capacity and speed of the negative pressure suction unit 2 can be adjusted by an external automation device or control equipment.

[0057] The detection end of the differential pressure sensor 4 is connected to the interior of the sealed cabin 1 .

[0058] The data acquisition end of the data recorder 5 is connected to the data output end of the pressure difference sensor 4. The data recorder 5 is used to collect and record the pressure difference data during the test. The data acquisition frequency is not less than 1 Hz, preferably 10 Hz to 1000 Hz.

[0059] The assumed true sealing performance is characterized by the pre-packaged product packaging leakage area S. The leakage area is analyzed by the pressure difference curve obtained by the sample test, and is obtained by combining the test results of the shaped box body with the assumed true sealing performance and the physical process of gas leakage and using a mathematical model.

[0060] According to the leakage area distribution of the shaped box, 9 shaped box models 6 with the same specifications and dimensions of the tested samples and the assumed real sealing performance are set.

[0061] Combination Figure 1 , Figure 2 , Figure 3 and Figure 4 , the implementation process can be described in the following specific steps:

[0062] Step 1: Measure the three-dimensional structure of the tested box body, prepare the above-mentioned 9 shaped box body models 6 with the same appearance as the tested sample and the assumed true sealing performance. The assumed true value can be measured by physical method and its leakage area is recorded as: 0, 3.1μm 2 , 7.1μm 2 , 12.6μm 2 , 23.5μm 2 , 245.8μm 2 , 375.8μm 2 , 610μm 2 , 947.7μm 2 .

[0063] Step 2: Set the total suction volume of the adjustable speed negative pressure suction unit 2 to 2 ml and the suction time to 20 s; place several shaped box models 6 in turn into the sealed cabin 1 containing the shaped box, and seal it before testing, start the adjustable speed negative pressure suction unit 2 to suction, and record the pressure difference change (Pi~t) during the suction process.

[0064] Step 3: Repeat step 2 using different shaped box models 6 to obtain pressure difference variation curves of several shaped box models 6, such as Figure 2 .

[0065] Step 4: From step 3Figure 2 The differential pressure change rate of each formed box body model 6 is obtained, and a relationship curve between the differential pressure change rate of the formed box body model 6 with an assumed true value and its leakage area S is further plotted, as shown in Figure 3 shown below

[0066] Step Five: From the Figure 3 relationship curve, a related mathematical model S = 1.24E28 × exp(dP i / dt) - 13.87 is established. This mathematical model is the operation equation for detecting the packaging leakage area of pre-packaged products

[0067] Step Six: Place the sample to be tested into the sealed chamber 1, repeat the above detection operation process, record the differential pressure change (Pi~t) during the suction process, calculate the differential pressure change rate (or other mathematical methods) f(Pi~t), substitute the differential pressure change rate (or other mathematical methods) into the operation equation for detecting the sealing performance obtained above, and calculate the sealing performance (leakage area) of the tested formed box body to be 4.15 μm 2 , thus completing one detection

Claims

1. A device for non-destructively testing the sealing degree of pre-packaged products by using dynamic pressure difference, characterized in that: It comprises a sealed cabin (1), a negative pressure suction unit (2), a pressure difference sensor (4), a data recorder (5) and a shaped box model (6); The sealed cabin (1) is used to accommodate the shaped box model (6) and the pre-packaged product to be tested; The negative pressure suction unit (2) has at least one air flow channel for completing the suction action, and the suction capacity and speed of the negative pressure suction unit (2) are adjustable; A connecting pipe (3) is provided between the sealed cabin (1) and the negative pressure suction unit (2), which is used to connect the sealed cabin (1) and the speed-adjustable negative pressure suction unit (2), so that the sealed cabin (1) and the negative pressure suction unit (2) are in airflow communication; The three-dimensional structural dimensions of the shaped box model (6) are consistent with the three-dimensional structural dimensions of the pre-packaged product to be tested, and the shaped box model (6) can assume the actual sealing performance of the pre-packaged product to be tested.

2. The device for non-destructively testing the sealing degree of pre-packaged products by using dynamic pressure difference according to claim 1 is characterized in that: The sealed cabin (1) has at least one opening for storing the cavity of the shaped box body to be tested. The opening can be sealed manually or automatically during testing, and the sealing degree meets the test requirements.

3. The device for nondestructively testing the sealing degree of pre-packaged products by using dynamic pressure difference according to claim 1, characterized in that: The suction capacity and speed of the negative pressure suction unit (2) can be adjusted by an external automation device or control equipment.

4. The device for nondestructively testing the sealing degree of pre-packaged products by using dynamic pressure difference according to claim 1, characterized in that: The detection end of the differential pressure sensor (4) may be connected to the interior of the sealed cabin (1) or to the interior of the connecting pipe (3).

5. The device for non-destructively testing the sealing degree of pre-packaged products by using dynamic pressure difference according to claim 1, characterized in that: The data acquisition end of the data recorder (5) is connected to the data output end of the pressure difference sensor (4), and the data recorder (5) is used to collect and record the pressure difference data during the test process, and the data acquisition frequency is not less than 1 Hz.

6. The device for nondestructively testing the sealing degree of pre-packaged products by using dynamic pressure difference according to claim 5, characterized in that: The data acquisition frequency is 10Hz~1000Hz.

7. The device for nondestructively testing the sealing degree of pre-packaged products by using dynamic pressure difference according to claim 1, characterized in that: It is assumed that the real sealing performance of the pre-packaged product to be tested is characterized by the leakage area S of the pre-packaged product packaging. The leakage area is analyzed by the pressure difference curve obtained by the sample test, and is obtained by combining the test results of a shaped box body that can assume the real sealing performance and the physical process of gas leakage and using a mathematical model.

8. The device for nondestructively testing the sealing degree of pre-packaged products by using dynamic pressure difference according to claim 1, characterized in that: The shaped box model (6) includes multiple groups according to different pre-packaged products to be tested.

9. The device for non-destructively testing the sealing degree of pre-packaged products by using dynamic pressure difference according to claim 1, characterized in that: For the same pre-packaged product to be tested, at least two shaped box models (6) are prepared, one of which has an assumed true sealing performance of no leakage, and the other has an assumed true sealing performance of lower than all the tested box packages.

10. The device for non-destructively testing the sealing degree of pre-packaged products by using dynamic pressure difference according to claim 1, characterized in that: According to the leakage area distribution of the shaped box, a plurality of shaped box models (6) with the same specifications and dimensions of the tested samples and the assumed real sealing performance are set.

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