The Hydrostatic head Tester test steps are as follows:
1. Hold the sample in the round table of the test sample. Test points should avoid the edges and folds of the cloth, and use enough tension to make the sample smooth without deformation. Gaskets should be placed on the low pressure side of the specimen (i.e., the side of the sample round table) to prevent air leakage. When there is a difference of air permeability between the two sides of the fabric, it should be recorded in the report.
2. Starting the suction fan is the air passing through the sample, regulating the flow, so that the pressure is gradually approaching the regulation value, and after 1min or when it reaches the stability, the air flow rate is recorded. Using the instrument of differential flowmeter, the appropriate aperture should be selected to record the pressure difference on both sides of the aperture.
3. Repeat at least 10 times in different parts of the same sample under the same conditions.
4. If there is a leak in the fixture, the air leakage should be measured and the value is subtracted from the reading.
Hydrostatic Pressure Tester Test Results calculation and presentation:
1. Calculate the arithmetic mean qv and variation coefficient of the measured value.
2. Calculate the ventilation rate R by formula (1) or (2). The result was 2% of the measurement range in GB 8170.
R = qv/Ax167 (mm/s)
Or R = qv/Ax0.167 (m/s)
In the formula,qv-- average gas flow, dm3/min;
A- test area, cm2;
167- conversion coefficient of mm/s by dm3/minxcm3;
0.167--- conversion coefficient of m/s by dm3/minxcm3;
3. Calculate the 95% confidence interval of the air permeability by formula 3.
The standard deviation of S--- standard deviation;
N -- test times;
T --95% confidence interval, degree of freedom of n-1.
1. Hold the sample in the round table of the test sample. Test points should avoid the edges and folds of the cloth, and use enough tension to make the sample smooth without deformation. Gaskets should be placed on the low pressure side of the specimen (i.e., the side of the sample round table) to prevent air leakage. When there is a difference of air permeability between the two sides of the fabric, it should be recorded in the report.
2. Starting the suction fan is the air passing through the sample, regulating the flow, so that the pressure is gradually approaching the regulation value, and after 1min or when it reaches the stability, the air flow rate is recorded. Using the instrument of differential flowmeter, the appropriate aperture should be selected to record the pressure difference on both sides of the aperture.
3. Repeat at least 10 times in different parts of the same sample under the same conditions.
4. If there is a leak in the fixture, the air leakage should be measured and the value is subtracted from the reading.
Hydrostatic Pressure Tester Test Results calculation and presentation:
1. Calculate the arithmetic mean qv and variation coefficient of the measured value.
2. Calculate the ventilation rate R by formula (1) or (2). The result was 2% of the measurement range in GB 8170.
R = qv/Ax167 (mm/s)
Or R = qv/Ax0.167 (m/s)
In the formula,qv-- average gas flow, dm3/min;
A- test area, cm2;
167- conversion coefficient of mm/s by dm3/minxcm3;
0.167--- conversion coefficient of m/s by dm3/minxcm3;
3. Calculate the 95% confidence interval of the air permeability by formula 3.
The standard deviation of S--- standard deviation;
N -- test times;
T --95% confidence interval, degree of freedom of n-1.
Fabric permeability refers to the air permeability of fabric in the presence of pressure difference on both sides of the fabric, that is, the volume of air flowing through the fabric per unit and area per unit time under the specified pressure difference between the two sides of the fabric.
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