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Detailed test steps of vacuum filtration performance of filter cloth

Update:13-11-2020
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Detailed test steps for the vacuum filtration performan […]

Detailed test steps for the vacuum filtration performance of the filter cloth (1) Sample preparation 1. Material preparation: Select porcelain clay for compressible materials, light calcium carbonate for similar compressible materials; use diatomaceous earth, flue ash or polycarbonate for non-compressible materials Vinyl chloride. Mix the selected materials with distilled water to prepare a suspension with a mass fraction of 1.0. Stir the suspension adequately and mix evenly.

2. The sampling method should be a filter cloth with no defects, no stripping, no damage, etc. After removing 1/10 of the width on both sides, evenly cut along the width of the filter cloth 5 A sample with a diameter of 125mm. Please use an electric soldering iron to trim the edge of the sample to ensure that the edge of the sample is uniform and does not fall off. 3. Disposal of the sample Put a single piece of the sample taken on the surface of distilled or deionized water, and the sample can sink due to its own weight. If the samples are stacked and soaked in water, they need to be soaked for 24h. (2) Measurement conditions 1. Measurement temperature measurement The ambient temperature is normal temperature. The samples of each type of filter cloth should be tested at the same temperature. 2. Distilled water or ion exchange water is required for water quality determination.

 

3. The filtration vacuum degree is 0.06665MPa (equivalent to 500mmHg), (3) Operation method 1. Calibrate as shown in Figure 2-19, open the filter 3, and place a blind rubber pad with a diameter of 125mm on the sample 7 , Tighten the bolts; turn on the vacuum valves 9 and 12. Start the vacuum pump 16, adjust the real air conditioning valve 14, check whether the mercury column on the U-shaped pipe differential pressure gauge 13 can reach above 0. 068MPa, if not, check the air tightness of the system Sex. After the inspection, close the vacuum pump 16, vacuum valves 9 and 12; open the intake valve 8 to make the system at normal pressure, and remove the rubber gasket. 2. The operation is shown in Figure 2-19. First, apply a layer of sealant on the edge of the filter clothWoven Filter Fabric Filter Press Cloth sample, then load the sample into position 7 of the filter 3, tighten the bolts, and ensure that the seal is lost; The slurry is poured into the feed tank 6; the feed valve 5 is turned over, the slurry is injected into the overflow barrel 4, and the stirring paddle is constantly in operation; the feed valve 5 is adjusted to make the flow barrel have nourishment; Close the vacuum valve 9, the drain valve 2, the intake valve 8 and the intake valve 14; start the vacuum pump 16, turn on the air conditioning valve 12, adjust the intake valve 14 so that the reading on the U-shaped differential pressure gauge 13 is slightly greater than 0.068 MPa; Open the vacuum valve 9 quickly, adjust the real air conditioning valve 14 to stabilize the vacuum at 0.06665MPa (equivalent to 500mmHg) and stop the suction filtration; when the filtrate enters the metering bottle 11, start timing, and check the online turbidity meter 10. Detect the turbidity of the filtrate and record the clearing time; when the filtrate in the metering bottle 11 reaches 500 mL, close the vacuum valve 9 and the vacuum pump 16, and record the time taken to collect 500 mL of shake. 4. Clarified that during the measurement process, only use tweezers to grip the edge of the sample to move the sample. It is not allowed to touch the surface of the tested sample with your fingers, and it is not allowed to curl or wrinkle the sample. Otherwise, you should prepare a new sample. The common vacuum degree of ordinary vacuum filter is in the range of 0.0533MPa-0.0800MPa (400mmHg-600mmHg). T is used to make the measurement conditions as close to the actual conditions as possible, and the vacuum degree is determined. . The maximum test area of ​​06665MPa (about 500mmHg) filter cloth is 6. 36 X 10-'m2. If the filtering rate of the filter cloth is faster and other supporting installations (such as the volume of the measuring bottle, etc.) cannot match it, the filter cloth can be reduced The opening diameter of the upper pressure ring can reduce the test area.

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