Introduction to the testing principle of medical textile air permeability tester

The Medical Textile Air Permeability Tester is one of the gas permeability testers in the family. It is suitable for testing the air permeability of a variety of textiles including industrial fabrics, nonwovens and other breathable products such as sponges and other materials, as well as highly breathable materials such as paper.

1. Basic Information

It is suitable for the air permeability test of various textile fabrics, including industrial fabrics, nonwoven fabrics and other textile products and other breathable materials.

2. Application Industry

It is widely used in food, medicine, packaging, plastics, industry, electronics, energy and other industries. It is suitable for plastic film, composite film, paper-plastic composite packaging, solar backplane, sheet, composite material, aluminized film, co-extruded film and other films, aluminum foil, sheet materials and plastic, rubber, paper, glass, metal and other materials such as bottles, bags, cans, boxes and other packaging containers.

3. Instrument Features

1. The instrument has its own temperature control function, which can simulate the condition of the product in the actual environment and meet various requirements of material permeability testing within the temperature range.

2. With unique fitting function, it can measure the air permeability, air permeability coefficient, solubility coefficient and diffusion coefficient of materials at -273℃~+200℃, and meet the requirements of testing and evaluating the air permeability of plastic films under special application conditions such as high and low temperatures.

3. Computer control, fully automatic testing

4. Determination of permeability, solubility, diffusion and permeability coefficient

5. Two test process judgment modes: proportional and fuzzy

6. Can expand the test of toxic, explosive and other dangerous gases

7. The measuring range can be extended by software setting

8. Standard film fast calibration

9. Network transmission interface supports centralized management of LAN data and Internet information transmission

4. Test Principle

Place the pre-treated sample between the upper and lower test chambers and clamp them. First, vacuum the low-pressure chamber (lower chamber) and then evacuate the entire system. When the specified vacuum degree is reached, close the lower test chamber and fill the high-pressure chamber (upper chamber) with a certain pressure of test gas. Ensure that a constant pressure difference (adjustable) is formed on both sides of the sample. In this way, the gas will penetrate from the high-pressure side to the low-pressure side under the action of the pressure gradient. By monitoring the internal pressure of the low-pressure side, the various barrier parameters of the tested sample can be obtained.

6. Usage Environment

1. The instrument should be placed on a flat and stable platform (or foundation).

2. There is no strong magnetic field or vibration source around the instrument.

3. The indoor atmosphere contains no corrosive media, no large dust particles, and the airflow is stable.

4. Environment: Temperature 20±3℃ Humidity RH: ≤65%

5. Use power supply Ac220V±10V, 50Hz, with good grounding. For areas with large fluctuations in external power supply, it is recommended to use a power stabilizer (AC220±1% 2kw).

7. Debugging steps

1. The instrument should be leveled before operation. The specific operation is to rotate the adjustable feet to make the instrument level.

2. Check whether the sample setting ring is tightened and whether its airtight ring is in close contact with the two joint surfaces.

3. Check whether the pressure head can be controlled to move up and down flexibly.

4. Check whether the connection between the suction hose, flow cylinder and suction fan is tight.

5. Check whether the door cover and door lock on the flow cylinder are tightly closed.

6. Check whether the printer is connected correctly.

7. Calibration

8. Check whether the instrument is leaking: Use a non-porous plate instead of the calibration plate for testing. If the air permeability screen displays a value of 0 (allowing fluctuations below 10Pa), it means there is no leakage. Otherwise, some part of the instrument is leaking and should be checked and adjusted.

8. Operation steps

1. Prepare the sample as required and cut it into specified size.

2. Select the sample setting circle and install it on the instrument.

3. Select the nozzle.

4. Turn on the instrument power.

5. Set parameters.

6. Press the start button to start the instrument.

7. The instrument automatically compresses the sample and starts testing. When the set pressure difference is reached, the sample is automatically released. The instrument automatically converts the test result and stops.

8. Test the next sample until the effective test number reaches the requirement (the display shows the test number) and process the data according to GB/T 5453-97.

9. The test results can be viewed on the air permeability/pressure difference display screen and can also be printed.

10. After the test is completed, turn off the power, clean the instrument and accessories, and remove the setting circle and put it in the spare parts drawer.

IX. Precautions

1. The instrument is a high-precision device. During the movement and transportation, collision and severe vibration are strictly prohibited.

2. The instrument has been calibrated before leaving the factory. Non-professionals are not allowed to repair the internal components of the instrument.

3. The instrument accessories (nozzle, nozzle seat and orifice plate, sample setting circle) are directly related to the test accuracy. It is not allowed to wipe them directly with a rag. If they are contaminated, use an ear blower to blow away the dust on the surface.

4. During the test, do not touch the sample to avoid affecting the air permeability of the sample.

5. The selection of nozzle diameter should be based on the air permeability of the sample. For samples whose air permeability is unclear, it is necessary to conduct several tests to make it more accurately reflect the air permeability of the sample.

6. The filter in the air flow cylinder should be cleaned regularly depending on the frequency of use.

7. If the instrument has been tested for a long time and the pressure difference value has not stabilized and the fan noise is continuously too loud, the instrument should be stopped to check the air tightness of each component or whether the selected test piece is within the measuring range.

8. For samples of different thicknesses, the position of the sample pressure head should be adjusted so that it can better and tightly press the sample.

9. Instrument testing is related to air atmospheric pressure. It is recommended to calibrate it once every working day. Instrument calibration should be performed by specialized personnel.

10. There are precision sensor components in the air flow cylinder. Be gentle when replacing the nozzle and cleaning it to avoid accidents.

11. The airtightness of each sealing joint directly affects the test accuracy and should be careful of contamination, deformation and damage.

12. Select the nozzle number: It is recommended to make the dynamic pressure difference fall in the range of 600~3000Pa to obtain more stable test results.