CN107907462B - Method for testing moisture permeability of container - Google Patents
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- CN107907462B CN107907462B CN201711075277.0A CN201711075277A CN107907462B CN 107907462 B CN107907462 B CN 107907462B CN 201711075277 A CN201711075277 A CN 201711075277A CN 107907462 B CN107907462 B CN 107907462B
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Abstract
The invention belongs to the technical field of measurement and test. The dew point humidity measuring technology of dynamic balance is adopted, and the balance point when the internal and external dew points of the closed container reach stable values is taken as a reference, so that the moisture permeability of the container is accurately tested and evaluated in engineering. The invention relates to a method for testing the moisture permeability of a container, which comprises the processes of determining test conditions, pretreating a sample, measuring carrier gas dew point, measuring carrier gas flow and testing the moisture permeability, wherein the dew point value of gas discharged from a gas outlet is measured by a dew point meter, and when the fluctuation within 3h of the dew point value is not more than +/-1.0 ℃, and the measured value is not unidirectionally changed, the last dew point value is taken as the final dew point value, and the moisture permeability of the container is calculated. The test method is simple to operate, low in test cost, high in universality and high in test efficiency, provides an engineering overall evaluation method for various pipelines, containers, packing boxes, sealing cavities and the like with moisture insulation requirements, and is suitable for testing and evaluating the overall moisture permeability of the sealing containers.
Description
Technical Field
The invention belongs to the technical field of measurement and test, relates to a humidity measurement technology, and particularly relates to a method for testing and evaluating the integral moisture permeability of a sealed container and a sealed box.
Background
Moisture permeability is an important technical parameter for representing the performance of a packaging material, and a great deal of literature reports are reported on a moisture permeability testing method, including various standards, patents and academic papers, but the moisture permeability testing method aims at testing the moisture permeability of materials (including films, sheets, plates and the like), samples need to be tested and prepared according to the standards, and few reports are reported on a moisture permeability testing technology of containers with certain geometric structures.
ZL201410403450.5 discloses a method for testing the whole moisture permeability of a closed box, which is to place a humidity sensor in the closed box after the geometric central point of the closed box, and to make the absolute humidity increment difference in the box in the interval of n times of continuous same time not more than plus or minus 0,1g/m3And when the relative humidity difference between the inside and the outside of the box body is not less than 30% RH, the method is taken as a measuring method of a test terminal. The humidity increment difference of the method is easily interfered by environmental fluctuation factors, so that the test time is continuously prolonged. The method is a static test method.
In practical engineering application, for an integral structure (such as a sealing box, a sealing container and the like) with a moisture insulation requirement, a main body and an auxiliary material meeting the technical requirement of moisture permeability are generally selected according to experience and are realized through engineering design and construction quality control, and at present, the integral moisture permeability of the engineering is rarely comprehensively evaluated by a definite method.
Disclosure of Invention
Provides a method for accurately testing and evaluating the moisture permeability of a container, which is simple and easy to implement by adopting a dew point humidity measurement technology and a method for measuring the balance of the internal dew point and the external dew point of the container.
The invention aims to provide a method for testing and evaluating the moisture permeability of a container, which realizes the measurement and engineering evaluation of the moisture permeability in engineering quality.
The invention aims to realize the purpose by adopting a dynamic equilibrium dew point humidity measurement technology and taking an equilibrium point when the internal and external dew points of a closed container reach a stable value as an evaluation standard. Air inlets and air outlets are respectively arranged on two end faces of the geometric length of the container to be tested close to the symmetric center and are sealed to form a closed system, the container is placed in a testing environment under the condition that the inside of the container is dry, carrier gas with known dew point humidity passes through the container at a stable flow rate, moisture permeating from the outside of the container to the inside of the container is uniformly carried out, the constant value of the dew point humidity of the gas discharged from the air outlet is constant after the inside of the container and the testing environment are balanced, and accurate testing and engineering evaluation are carried out on the moisture permeability of the. The method of prolonging the gas inlet pipeline is used for preheating the carrier gas to the temperature of the testing environment, and the gas inlet pipeline and the gas outlet pipeline use metal pipelines so as to reduce the influence of the pipelines on the testing result.
The invention relates to a method for testing the moisture permeability of a container, which comprises the processes of determining test conditions, pretreating a sample, measuring carrier gas dew point, measuring carrier gas flow and testing the moisture permeability, and is characterized in that:
1) and (3) determining test conditions: setting the testing temperature and humidity according to the technical requirements of the container to be tested;
2) sample pretreatment: an air inlet and an air outlet are respectively arranged near the center of two end surfaces of the geometric length of the container, and are connected with an air inlet pipeline and an air outlet pipeline and sealed; dedusting and dehumidifying the inside of the closed container;
3) and (3) measurement of dew point of carrier gas: measuring and recording a carrier gas dew value as a background value of the moisture content of the carrier gas;
4) testing the moisture permeability of the container: placing the closed container into a test box with balanced test environment, opening carrier gas, adjusting the flow of the carrier gas to stabilize the carrier gas, and accurately measuring the flow value; introducing carrier gas into the closed container to be tested, measuring the dew point value of gas discharged from the gas outlet by using a dew point meter, taking the last dew point value as the final dew point value when the fluctuation degree is not more than +/-1.0 ℃ within 3h and the measured value is not unidirectionally changed, calculating the moisture permeability of the container according to the formula (1), and calculating the absolute humidity under the test condition according to the formula (2):
in the formula:
Wtthe moisture permeability of the container is given in g/(m)2·24h)；
dv1Absolute humidity in g/m under test conditions corresponding to the carrier gas background dew value3；
dv2Absolute humidity in g/m under test conditions corresponding to the final dew value of the gas outlet carrier gas3；
F is carrier gas flow, and the unit is L/min;
s-surface area of the vessel in m2；
In the formula:
dvabsolute humidity in g/m under the test conditions corresponding to the dew point value of the carrier gas3；
e is a natural constant;
Tddew point temperature in deg.C.
T-temperature of the carrier gas in units of ℃.
The invention relates to a method for testing the moisture permeability of a container, which comprises the processes of determining test conditions, pretreating a sample, measuring carrier gas dew point, measuring carrier gas flow and testing the moisture permeability, and is characterized in that: the carrier gas flow is between 1L/min and 5L/min.
The invention relates to a method for testing the moisture permeability of a container, which comprises the processes of determining test conditions, pretreating a sample, measuring carrier gas dew point, measuring carrier gas flow and testing the moisture permeability, and is characterized in that: the dehumidification of the container is reduced to below 20 percent RH in the sample pretreatment process.
The invention relates to a method for testing the moisture permeability of a container, which comprises the processes of determining test conditions, pretreating a sample, measuring carrier gas dew point, measuring carrier gas flow and testing the moisture permeability, and is characterized in that: the gas flow is measured using a mass flow meter.
The invention relates to a method for testing the moisture permeability of a container, which comprises the processes of determining test conditions, pretreating a sample, measuring carrier gas dew point, measuring carrier gas flow and testing the moisture permeability, and is characterized in that: the air inlet and the air outlet of the container are hermetically connected with the air inlet and the air outlet pipelines by threads.
The invention relates to a method for testing the moisture permeability of a container, which comprises the processes of determining test conditions, pretreating a sample, measuring carrier gas dew point, measuring carrier gas flow and testing the moisture permeability, and is characterized in that: the air inlet and outlet of the container are hermetically connected with the air inlet and outlet pipelines by adopting double cutting sleeves or a VCR.
The invention relates to a method for testing the moisture permeability of a container, which comprises the processes of determining test conditions, pretreating a sample, measuring carrier gas dew point, measuring carrier gas flow and testing the moisture permeability, and is characterized in that: the length of the air inlet pipeline in the test box in the test process is not less than 3 m.
The invention relates to a method for testing the moisture permeability of a container, which comprises the processes of determining test conditions, pretreating a sample, measuring carrier gas dew point, measuring carrier gas flow and testing the moisture permeability, and is characterized in that: the gas inlet and outlet pipelines are metal pipelines.
The invention relates to a method for testing the moisture permeability of a container, which comprises the processes of determining test conditions, pretreating a sample, measuring carrier gas dew point, measuring carrier gas flow and testing the moisture permeability, and is characterized in that: the dehumidification method in the sample pretreatment process is a drying agent adsorption method or a dry gas blowing method.
The method for testing the moisture permeability of the container adopts a dew point meter, a flowmeter, a common environment test and measurement equipment, does not need a special test instrument, has simple operation, low test cost, strong universality and high test efficiency, provides an engineering overall evaluation method for various pipelines, containers, packing cases, sealed cavities and the like with moisture insulation requirements, and is suitable for testing and evaluating the overall moisture permeability of the sealed container.
Detailed description of the preferred embodiments
The moisture permeability test method for sealed containers according to the present invention is described in further detail below by way of example, but not by way of limitation to the technical solutions of the present invention.
Example one
The external mechanical dimensions of the container to be tested were phi 6mm × 13.56.56 m FEP tubular container with wall thickness 0.5mm, tableThe area is 0.2555m2。
The test conditions were: temperature (40 +/-1) DEG C and relative humidity (90 +/-2)%.
The two ends of the air inlet and the air outlet of the tubular container are connected and sealed by a threaded quick-insertion pipe joint, and the front end of the air inlet is connected with a section of stainless steel pre-heating pipeline with the length of 3m and the diameter of phi 6mm by a double-clamping sleeve thread.
Sample pretreatment: connecting a pressure reducing valve, a mass flow meter and a pipeline by using high-purity nitrogen filled in a steel cylinder, purging for 0.5H at the flow rate of 5L/min to dry and clean the interior of the container, measuring the discharged gas at a gas outlet by using a THT-2H type temperature and humidity measuring instrument, sealing the container when the measured humidity value is lower than 20% RH, and quickly putting the pretreated sealed container into an environmental test box in a balanced state.
And (3) measurement of dew point of carrier gas: connecting 40L of steel cylinder filled high-purity nitrogen, a pressure reducing valve, a mass flow meter and a dew point meter according to a conventional method, controlling the stable flow to be 1.0L/min, and measuring the background dew point value of the steel cylinder filled high-purity nitrogen to be-61.12 ℃. Calculating the absolute humidity d corresponding to the background dew point value of the carrier gas under the corresponding test condition according to the formula (2)v1：
And (3) testing the moisture permeability of the container and calculating data: connecting a pressure reducing valve, a mass flowmeter, a pipeline, a tested sealed container and a dew point instrument by using steel cylinder high-purity nitrogen, controlling the flow to be 1.0L/min, recording a group of dew point values every 15min, achieving moisture permeability balance within 4.5h, enabling the dew point value within 3h to be not changed in a single direction, controlling the fluctuation degree to be 0.16 ℃, and taking the last dew point value to be 49.47 ℃ as the final dew point value. Experimental procedures test data are shown in table 1.
Table 1 test procedure test data
| Time of day | Dew point/. degree.C |
| 09:45 | -22.06 |
| 10:00 | -37.28 |
| 10:15 | -45.17 |
| 10:30 | -47.24 |
| 10:45 | -49.42 |
| 11:00 | -49.37 |
| 11:15 | -49.37 |
| 11:30 | -49.41 |
| 11:45 | -49.49 |
| 12:00 | -49.33 |
| 12:15 | -49.36 |
| 12:30 | -49.45 |
| 12:45 | -49.45 |
| 13:00 | -49.47 |
| 13:15 | -49.41 |
| 13:30 | -49.40 |
| 13:45 | -49.47 |
| 14:00 | -49.35 |
| 14:15 | -49.47 |
Calculating the absolute humidity d corresponding to the dew point value of the carrier gas under the test condition according to the formula (2)v2：
The container moisture permeability is calculated from equation (1):
example two
The sealed container to be tested in the first embodiment is a test object. Only the control flow is changed to be 2.0L/min, and other conditions are not changed.
And (3) measurement of dew point of carrier gas: the high-purity nitrogen gas filled in a 40L steel cylinder is connected with a pressure reducing valve, a mass flowmeter and a dew point meter, and the flow is controlled to be2.0L/min, and the background dew point value of the steel cylinder filled with the high-purity nitrogen is measured to be-66.26 ℃. Calculating the absolute humidity d corresponding to the background dew point value of the carrier gas under the corresponding test condition according to the formula (2)v1：
And (3) testing the moisture permeability of the container and calculating data: connecting a pressure reducing valve, a mass flowmeter, a pipeline, a tested sealed container and a dew point instrument by using steel cylinder-packed high-purity nitrogen, controlling the flow to be 2.0L/min, recording a group of dew point values every 15min, achieving moisture permeability balance within 4.0h, enabling the dew point value within 3h to be not changed in a single direction, controlling the fluctuation degree to be 0.45 ℃, and taking the last dew point value-55.01 ℃ as the final dew point value. Experimental procedures test data are shown in table 2.
TABLE 2 test data for sealed container test procedures
| Time of day | Dew point/. degree.C |
| 10:00 | -18.33 |
| 10:15 | -25.06 |
| 10:30 | -38.79 |
| 10:45 | -51.22 |
| 11:00 | -55.10 |
| 11:15 | -54.86 |
| 11:30 | -54.99 |
| 11:45 | -54.95 |
| 12:00 | -55.13 |
| 12:15 | -54.96 |
| 12:30 | -54.72 |
| 12:45 | -54.66 |
| 13:00 | -55.03 |
| 13:15 | -55.05 |
| 13:30 | -54.90 |
| 13:45 | -54.68 |
| 14:00 | -55.01 |
According to the formula (2)) Calculating the absolute humidity d corresponding to the dew point value of the carrier gas under the test conditionv2：
The container moisture permeability is calculated from equation (1):
the test results are in agreement with the moisture permeability test and the calculated values in example one.
EXAMPLE III
The external mechanical dimension of the tested container is a rectangular box body with the thickness of 5mm and the external mechanical dimension of 2.50m × 0.45.45 m × 0.45.45 m, the main body plate surface is made of non-metal composite materials, the interior of the main body plate is provided with structural components such as more complex supporting pieces, and the surface area is 4.905m2。
The test conditions were: the temperature is 35 +/-2 ℃ and the relative humidity is 95 +/-3 percent.
Two cover plates are arranged near the centers of two end surfaces of the geometric length of the rectangular box body, the cover plates are connected with a double-clamping sleeve joint through threads, the cover plates at the two ends are respectively used as an air inlet and an air outlet, and the front end of the air inlet is connected with a section of stainless steel pre-heating pipeline with the length of 5m and the diameter of phi 6mm through the double-clamping sleeve threads.
Sample pretreatment: 4 bags of allochroic silica gel which is dried and packaged by a breathable bag, 5kg in total, are distributed in the box body and used for adsorbing moisture in the box body, the THT-2H type temperature and humidity measuring instrument sensor probe is placed near the central position in the box body, and the box body is sealed. When the humidity value measured by the temperature and humidity measuring instrument is lower than 20% RH, the drying agent is quickly taken out in a dry environment, the box body is closed, the pipeline is connected, and the pretreated sealed container is quickly placed into an environmental test chamber in a balanced state.
And (3) measurement of dew point of carrier gas: connecting 40L of steel cylinder filled high-purity nitrogen, a pressure reducing valve, a mass flow meter and a dew point meter according to a conventional method, controlling the stable flow to be 5.0L/min, and measuring the background dew point value of the steel cylinder filled high-purity nitrogen to be-65.56 ℃. Under the corresponding test conditions calculated according to the formula (2),absolute humidity d corresponding to carrier gas background dew valuev1：
And (3) testing the moisture permeability of the container and calculating data: connecting a pressure reducing valve, a mass flowmeter, a pipeline, a tested sealed container and a dew point instrument by using steel cylinder high-purity nitrogen, controlling the flow to be 5.0L/min, recording a group of dew point values every 15min, achieving moisture permeability balance within 6.5h, enabling the dew point value within 3h to be not changed in a single direction, controlling the fluctuation degree to be 0.59 ℃, and taking the last dew point value to be 47.09 ℃ as the final dew point value. Experimental procedures test data are shown in table 3.
TABLE 3 test data for sealed container test procedures
Calculating the absolute humidity d corresponding to the dew point value of the carrier gas under the test condition according to the formula (2)v2：
The container moisture permeability is calculated from equation (1):
Claims (8)
1. a method for testing the moisture permeability of a container comprises the processes of determining test conditions, pretreating a sample, measuring carrier gas dew point, measuring carrier gas flow and testing the moisture permeability, and is characterized in that:
1) and (3) determining test conditions: setting the testing temperature and humidity according to the technical requirements of the container to be tested;
2) sample pretreatment: an air inlet and an air outlet are respectively arranged near the center of two end surfaces of the geometric length of the container, and are connected with an air inlet pipeline and an air outlet pipeline and sealed; dedusting and dehumidifying the inside of the closed container;
3) and (3) measurement of dew point of carrier gas: taking high-purity nitrogen as a carrier, measuring and recording a carrier gas dew point value as a background value of the carrier gas moisture content;
4) testing the moisture permeability of the container: putting the closed container into a test box with balanced test environment, opening carrier gas, adjusting the carrier gas flow to be stable, and accurately measuring the flow value, wherein the carrier gas flow is between 1L/min and 5L/min; introducing carrier gas into the closed container to be tested, measuring the dew point value of gas discharged from the gas outlet by using a dew point meter, taking the last dew point value as the final dew point value when the fluctuation degree is not more than +/-1.0 ℃ within 3h and the measured value is not unidirectionally changed, calculating the moisture permeability of the container according to the formula (1), and calculating the absolute humidity under the test condition according to the formula (2):
in the formula:
Wtthe moisture permeability of the container is given in g/(m)2·24h)；
dv1Absolute humidity in g/m under test conditions corresponding to the carrier gas background dew value3；
dv2Absolute humidity in g/m under test conditions corresponding to the final dew value of the gas outlet carrier gas3；
F is carrier gas flow, and the unit is L/min;
s-surface area of the vessel in m2；
In the formula:
dvabsolute humidity in g/m under the test conditions corresponding to the dew point value of the carrier gas3；
e is a natural constant;
Td-dew point temperature in units of;
t-temperature of the carrier gas in units of ℃.
2. The method for testing moisture permeability of a container according to claim 1, wherein: the dehumidification of the container is reduced to below 20 percent RH in the sample pretreatment process.
3. The method for testing moisture permeability of a container according to claim 1, wherein: the gas flow is measured using a mass flow meter.
4. The method for testing moisture permeability of a container according to claim 1, wherein: the air inlet and the air outlet of the container are hermetically connected with the air inlet and the air outlet pipelines by threads.
5. The method for testing moisture permeability of a container according to claim 4, wherein: the air inlet and outlet of the container are hermetically connected with the air inlet and outlet pipelines by adopting double cutting sleeves or a VCR.
6. The method for testing moisture permeability of a container according to claim 1, wherein: the length of the air inlet pipeline in the test box in the test process is not less than 3 m.
7. The method for testing moisture permeability of a container according to claim 1, wherein: the gas inlet and outlet pipelines are metal pipelines.
8. The method for testing moisture permeability of a container according to claim 1, wherein: the dehumidification method in the sample pretreatment process is a drying agent adsorption method or a dry gas blowing method.
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| CN110057736B (en) * | 2019-04-08 | 2021-08-03 | Tcl华星光电技术有限公司 | Method and equipment for detecting moisture permeability of organic film |
| CN112595754B (en) * | 2020-12-02 | 2022-05-24 | 株洲时代新材料科技股份有限公司 | Water-spreading rate testing device and testing method |
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| CN101809427A (en) * | 2007-09-28 | 2010-08-18 | 株式会社爱发科 | Device for measuring steam permeability, and method for the device |
| CN104132883A (en) * | 2014-06-11 | 2014-11-05 | 中国兵器工业集团第五三研究所 | Testing method for whole moisture penetrability of closed box body |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101809427A (en) * | 2007-09-28 | 2010-08-18 | 株式会社爱发科 | Device for measuring steam permeability, and method for the device |
| CN104132883A (en) * | 2014-06-11 | 2014-11-05 | 中国兵器工业集团第五三研究所 | Testing method for whole moisture penetrability of closed box body |
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| 《Model Description WaSiM 2015》;Schulla J.;《Model Description WaSiM》;20151231;第72页最后一段-第73页第2段 * |
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