The gravel screen uses the relative motion of granular materials and screen surface to make part of the particles through the sieve and classify sand, gravel, crushed stone and other materials be divided into different levels according to mechanical particle size.
The screening particle depends on the screen surface. There are three types of sieve surface: grate gate, plate sieve and mesh sieve. Grate gate is suitable for screening particulate material, the grate gate slit is 1.1 to 1.2 times of the diameter of material particle under sieve, generally not less than the 50 mm. Plate screen is a steel plate with holes on it, the holes are round, square or rectangular of aperture 10 to 80 mm with longer service life and non-clogging, applicable to the screening medium particles. Mesh wire is woven or welded by steel wire; the holes are square, rectangular or elongated and the common aperture is generally 6 to 85 mm, suitable for screening wet materials; it has large effective area.
Screening machine can be divided into fixed sieve and movable sieve two categories. Movable sieve also can be divided into revolving screen and vibrating screen.
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Necessity for selection
1. The usage of the sieve: for grading, dehydration, sculping or desliming.
2. Material that to be sieved: dry material or wet material.
3. Installation space dimensions: the width of the screen surface B, length L and height H
4. Screen classification: 1, fixed screen surface;2, vibrating screen surface; 3, movable screen surface; 4, drum sieve surface; 5, other types of sieve surface.
5. The maximum particle size of feeding and discharging.
6. The sizes of interface equipment and follow-up equipment.
7. Equipment handling capacity.
8. Installation forms: block or hanging; motor is of left installation or right installation.
9. The electronic cabinet installation and control linkage order, the selection requirements of motor and electric control.
10. Other special requirements: screen surface inclination and sieve appearance colors, etc.