Test steps of synthetic blood penetration tester for medical masks

The synthetic blood penetration tester for medical masks is used to measure the penetration performance of liquid jets such as synthetic blood to evaluate its safety protection performance. 

Main application: It is suitable for the determination of the penetration performance of synthetic blood splash of medical melt-blown filter materials. It can be used by medical inspection departments, safety inspection departments and scientific research institutions.

The medical mask sample is supported on the test device, and 2mL of synthetic blood is sprayed horizontally from a cannula with an inner diameter of 0.84mm toward the meltblown filter material to be tested at a distance of 300mm. The scene of blood splashing from a perforated blood vessel is simulated, and the penetration of synthetic blood on the other side of the meltblown filter material is observed. The medical mask samples are tested at the liquid spray pressures corresponding to the liquid spray speeds of 450cm/s, 550cm/s, and 635cm/s. The test results of each spray speed are recorded, and the corresponding high blood pressure of the acceptable quality level limit of 4 for medical masks is given.

experiment procedure:

1. Pull the handle of the sample clamp on the upper left of the instrument and pull the sample clamp to the left. Fix the sample (the standard requires that the sample be tested within 60 seconds after being taken out of the pretreatment chamber) on the sample clamp. If the melt-blown filter material has wrinkles, unfold the wrinkles and fix them on the sample clamp to ensure that the target area is a single layer of material. The center of the sample is used as the test target area. Close the sample clamp.

2. Press the "Start" button. At this time, a certain amount of synthetic blood (surface tension (0.042±0.002) N/m) is sprayed horizontally toward the melt-blown filter material behind the positioning target. At the same time, the timer starts timing. After the set spraying time, the instrument automatically stops spraying. After 10 seconds, the buzzer sounds. Press the "Stop" button and check whether there is synthetic blood on the observation surface of the sample.

3. One test is over. If you need to continue the test, repeat steps AC until all tests are completed. After all the tests are completed, clean the synthetic blood residue in the test liquid box, replace it with distilled water, and clean the entire pipeline. When the nozzle sprays out clean water, continue to drain all the clean water in the test liquid tank. Close the outlet valve on the air compressor and turn off the power switch. Wash the residual liquid tray, clean the work surface, and clean the distilled water in the test liquid box.

4. Positioning target test. First, close the outlet valve on the air compressor, connect the air compressor to the power supply, and wait until the air compressor reaches the predetermined pressure. Cut off the power supply of the air compressor, turn off the gas source switch, open the outlet valve, pull up the valve head of the filter pressure reducing valve on the left side of the instrument, and follow the valve head indication. The "+" direction is for pressurization, and the "-" direction is for pressure reduction adjustment, so that the pressure gauge of the filter pressure reducing valve displays 0.2MPa. Install the positioning target so that the distance between the back of the positioning target and the melt-blown filter material sample is 10mm, and tighten the positioning screw on the guide plate at the bottom of the positioning target to position it.

5. Turn the air source switch on the left side of the instrument to off (vertical is off), turn on the power switch, press the "apply test solution" key, pay attention to the return pipe above the test solution box, and press the "apply test solution" key immediately when test solution flows out of the return pipe. The test solution is applied.

After using the positioning ruler to determine that the distance from the nozzle to the mask is (300±10) mm, use the screws to fix the positioning target seat. Unscrew the air source switch on the left side of the instrument (the knob is horizontal), adjust the precision pressure reducing valve on the top of the instrument, follow the valve head indication, the "+" direction is for pressurization, and the "-" direction is for pressure reduction adjustment, refer to Table 2 to adjust the pressure gauge pressure, set the "Injection Time" timer on the panel to 1min or longer, press the "Start" button, loosen the nozzle positioning screw, adjust the nozzle up and down, left and right, so that the ejected test liquid flow is aligned with the center of the small hole on the positioning target plate in a straight line, tighten the positioning screw, and press the "Stop" button.

Set the "Spray Time" timer on the panel to 1s, press the "Start" key, spray the test liquid for 1s and then stop spraying. Use a balance to weigh the mass of the liquid sprayed from the nozzle to ensure that the mass of the sprayed liquid is within the range given in Table 2. If it is not within the range, you can fine-tune the pressure value (refer to 6.2.4 for the method of aligning the liquid with the target hole) to make the mass of the liquid passing through the target hole within the range given in Table 2.

The relationship between the pressure of the reference pressure gauge and the injection time is shown in Table 3. Under different pressures, the injection time is adjusted so that the volume of the liquid that passes through the target hole after three consecutive injections is 2mL. For the test liquid with a density of 1.005g/mL, the mass is 2.01g. If the volume of the liquid ejected from the nozzle (taken from the place where the sample is placed) is not 2mL, the injection time can be adjusted appropriately to ensure that the volume of the liquid that passes through the target hole is 2mL. (Three sets of samples corresponding to the three injection speeds of 450 cm/s, 550 cm/s, and 635 cm/s need to be prepared for the test. Tests are carried out separately according to different injection speeds to evaluate the sample's resistance to synthetic blood penetration), and then the test is carried out according to the following steps.

6. Test steps

Hold the handle of the sample clamp on the upper left of the instrument and pull the sample clamp to the left. Fix the sample (the standard requires that the sample be tested within 60 seconds after being taken out of the pretreatment chamber) on the sample clamp. If the melt-blown filter material has wrinkles, unfold the wrinkles and fix them on the sample clamp to ensure that the target area is a single layer of material. The center of the sample is used as the test target area. Close the sample clamp. Press the "Start" button. At this time, a certain amount of synthetic blood (surface tension (0.042±0.002) N/m) is sprayed horizontally toward the melt-blown filter material to be tested behind the positioning target. The spraying starts, and the time relay starts timing. After the set spraying time, the instrument automatically stops spraying.

After 10 seconds, the buzzer sounds. Press the "Stop" button to open the sample holder. Under appropriate lighting conditions, check whether synthetic blood appears on the observation surface of the sample. One test is over. If you need to continue the test, repeat steps AC until all tests are completed.

After the test is completed, clean the synthetic blood residue in the test liquid box, replace it with distilled water, and clean the entire pipeline. When the nozzle sprays out clean water, continue to drain all the clean water in the test liquid tank. Close the outlet valve on the air compressor and turn off the power switch. Wash the residual liquid tray, clean the work surface, and clean the distilled water in the test liquid box.