How to test the mechanical properties of filter materials (from which three aspects)
1. Detection of breaking strength and elongation of filter material
The preparation, testing and calculation of test samples for the breaking strength and elongation of filter materials shall be conducted in accordance with GB/T3923.
(1) Preparation of test samples The parallel method is usually used for sample cutting, but the trapezoidal method is used for international trade arbitration inspection.
From a batch or a load of goods, randomly cut a full width of at least Im length from each piece of batch samples according to Table 3-36 as the laboratory sample.
1) Parallel method: at least 5 longitudinal and latitudinal samples shall be cut from each piece of cloth. The length direction of each sample is parallel to the warp or weft of the fabric. It is required that the length direction of two samples shall not contain the same yarn. If the width is less than W0cm, the warp direction shall be cut at 1/10 of the width from the cloth edge. If the width is greater than W0cm, the warp direction shall be cut at 10cm from the cloth edge
2) Trapezoidal method: each sample shall be cut on the piece of cloth with a length of about lm. At least 5 samples in warp and weft direction shall be cut. The length direction of each sample shall be parallel to the warp or weft of the fabric and arranged in a trapezoidal manner. It is required that the length direction of two samples shall not contain the same yarn, and the warp direction shall be 1/1 from the edge of the cloth. Cut at the width.
(2) Test method The determination of fabric breaking strength and elongation at break can be conducted by any one of the constant speed elongation testing machine, constant speed traction strength testing machine, and constant load strength testing machine, but it is required to be conducted at the same breaking time. Generally, the average fracture time of the specimen is specified as 20 ± 3s.
Place the sample in the clamp of the testing machine, and make it conform to the above nominal clamping length and maintain a certain pre tension. Adjust the running speed, carry out the test according to the measured quantity required for the test, record the breaking strength and elongation at break of each sample, and then calculate the average breaking strength and elongation at break.
2. Detection of elongation of filter material under constant load
1) For long internal filter bags with a length of more than 5m, high strength and low elongation filter materials shall be used. This kind of filter material shall meet the requirements of GB/T12625 and be subject to the elongation test under constant load in the longitudinal direction. Determination method of elongation under constant load: prepare three samples with nominal clamping length of 200mm and width of 50mm;
2) Clamp and fix one end of the sample, and load 40N on the other end;
3) Unload after standing for 24h, take down the sample and measure its length;
4) Calculate the elongation (%) of three samples respectively, and then calculate the average value.
3. Detection of bursting strength and bursting strength of filter material
For glass fiber filter material, in addition to its breaking strength and elongation at break, the bursting strength or bursting strength shall also be tested.
The filter material is pushed in with a steel ball under tension, and the strength in case of damage is called bursting strength. The bursting strength is usually tested by adding a bursting strength test accessory to the filter material strength tester.
The bursting strength of filter material is the fluid pressure (kN/m2) that acts on a certain area of sample to make it expand and rupture.
The bursting strength is tested with a bursting strength tester (see Fig. 3-50). Place a certain area of filter material sample on the elastic die, clamp both with a circular fixture of specified size, and then gently apply fluid pressure to the diaphragm until the sample breaks