Operation method of hydraulic pressure test of composite fabrics
Common testing standards JISL1092A&JISL1092B, AATCC127, ISO811, GB/4744.
Test principle: The hydrostatic pressure endured by the fabric represents the resistance encountered by water penetrating the fabric. Under standard atmospheric conditions, one side of the specimen is subjected to a continuously rising water pressure until water seepage occurs in three places.
Test sampling: Take three 20cm*20cm samples diagonally from the fabric (1 meter away from the fabric end, 15 cm away from the fabric edge) and keep it in a constant temperature and constant room for more than 24 hours to make the samples as representative as possible. The object being tested must not have wrinkles, creases, holes, etc. After taking the sample, try to touch it with your hands as little as possible and avoid folding it hard. (Except for dehumidification, no treatment is required, such as ironing, etc.)
Steps: Put the sample into the clamping device. The operator should not put his hand in to avoid pinching his hands. POWER turns on the power – ENTER enters the test mode selection – SELECT selects the test mode: select speed 1 (10cmH2O/Min) or selects speed 2 (60cmH2O/Min) – ENTER enters the test mode – START starts pressurization – until the test When the third water drop appears on the sample, record the value displayed on the display screen – STOP to release pressure – ESC lifts the pressure ring, takes out the sample, and conducts the next test.
Precautions for hydrostatic testing of composite fabrics
1． Coated fabrics are fully glued and can be tested with the coating side facing up or with the fabric facing up. Filmed fabrics are glued in spots or single films and elastic fabrics. The test surface needs to be padded with a backing material, or the film should be tested with the film facing down. , to avoid breaking the film due to pressure during the test.
2． The surface of the fabric with greater elasticity needs to be padded with a backing cloth, otherwise the fabric will be too elastic and will push against the support frame at a certain value, causing the sample to burst.
3． The fabric is granular fabric such as polar fleece, woolen cloth, etc. During the test process, the pressure ring of the instrument cannot press the test object firmly, causing water to seep from the edge of the test pressure ring during the test. In such cases, the test values obtained cannot be used as The basis for judging product conformity.
4． Application of foil materials: mainly woven lightweight 50D*50D/300T nylon fabric and warp knitted 20D Tricod mesh. When outsourcing testing, supporting materials should be attached and marked on the outsourcing testing application form.
5． When encountering the above situation, a written explanation must be included in the test record report.
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