Hydrodynamic Sieve Test Apparatus

The percentage passing of different fractions determines the porometry of the geotextile investigated. In the Hydrodynamic Sieving Method, the geotextile specimen, loaded with a certain quantity of glass bead fraction, is continuously rotated in a water trough, forcing the glass beads to pass through the geotextile openings. The apparatus consists of two test drums of 14 cm dia and 7 cm effective length with 16 nos. of 4 mm dia rods provided circumferentially at equal spacing to hold the geotextile specimen in position. Two troughs to contain the test drums are supported on horizontal axis, facilitating free rotation and capable of being filled with distilled water to a level of 20 mm below the drum axis. The clearance between the trough and the geotextile could be maintained at about 40 mm. The apparatus is provided with a motor drive and gear assembly to enable rotation of the drums at a speed of 5 rpm to 30 rpm. For conducting the test, the Geotextile specimen is cut and stitched to get a shape of 14 cm dia and 10 cm length to insert over the drum tightly, after immersing the specimen in distilled water for one hour, and secured by rubber 'O' rings. After placing 50 g of smallest size glass beads inside the drum, the lid is secured and the drum with the geotextile placed in distilled water to the desired level and rotated at 20 rpm for 1,500 cycles. In order to get the optimum filtration opening size, the drum is rotated at a speed of 5 rpm to 30 rpm for 250 to 2,500 revolutions. The percentage of beads passed through the geotextile by dry weight is determined. The test is repeated with increasing size of glass beads till 5% or less of the beads by weight pass through the geotextile. 
Rounded Beads made of glass, size 0.85 mm (passing 1 mm and retained at 0.85 mm)
Rounded Beads made of glass, size 0.425 mm (passing 0.85 mm and retained at 0.425 mm)
Rounded Beads made of glass, size 0.25 mm (passing 0.425 mm and retained at 0.25 mm)
Rounded Beads made of glass, size 0.18 mm (passing 0.25 mm and retained at 0.18 mm)
Rounded Beads made of glass, size 0.15 mm (passing 0.18 mm and retained at 0.15 mm)
Rounded Beads made of glass, size 0.075 mm (passing 0.15 mm and retained at 0.075 mm)

SGE-1018