The vibration force generated by the vibration source of the circular vibrating screen is an inertial force that changes direction normally around the fixed axis. Its essence is the centrifugal force formed by the rotation of the eccentric mass around the fixed axis. The working principle of the circular vibrating screen is that after the vibrating screen is started, the vibrating screen exciter drives the vibrating screen box to perform directional jumping movement. At the same time, materials smaller than the screen holes fall through the screen holes into the lower layer and become the materials under the screen holes. Materials larger than the screen holes are discharged from the outlet after continuous jumping, and finally the screening work is completed.

Circular Motion Coal Sieve Vibrating Screen

Parameter selection of circular vibrating screen
(1) Throwing index

Generally, according to the purpose of screening, circular vibrating screen generally adopts KV=3~5, and vertical vibrating screen adopts KV=2.5~4. For difficult-to-screen materials, a larger value is used, and for easy-to-screen materials, a smaller value is used. For small screen holes, a larger value is used, and for large screen holes, a smaller value is used.

(2) Vibration intensity

The selection of vibration intensity K is mainly limited by material strength and component stiffness. At present, the mechanical level K value is generally in the range of 3~8, and the vibrating screen is mostly 3~6.

(3) Screen surface inclination

Circular vibrating screen generally takes 15°~25°, and takes a smaller value when the amplitude is large, and takes a larger value when the amplitude is small.

(4) Screen box amplitude

The screen box amplitude A is an important parameter for designing the screen, and its value must be appropriate to ensure that the material is completely stratified, reduce clogging, and penetrate the screen. Generally, A=3~6mm is used, where the screen hole is large and the screen hole is small.

Selection tips for circular vibrating screens
The main factors for selecting the type of screening machine are:

The characteristics of the screening material (the content of the screening material particles, the content of difficult-to-screen particles, the content of water and clay in the material, the shape of the material, the proportion of the material, etc.);

Screening machine structure (screen area, number of screen layers, screen hole size and shape, screen hole area ratio, screening machine movement mode, amplitude and frequency, etc.).

Mineral processing requirements (processing capacity, screening efficiency, screening method, screening machine inclination), etc.

In addition to considering the above influences, the following basic principles should also be followed:

(1) After the screening area is determined, the screen width should be at least 2.5~3 times the maximum material size to prevent the screen from being blocked by large materials. Blockage.

(2) The sieve can be in good working conditions. The ratio of the sieve length to the width should be selected within the range of 2 to 3.

(3) Reasonable sieve surface materials and structures should be selected to suit the working conditions.

(4) Determination of the sieve hole size. For fine screens, arc screens, and linear vibrating screens, the sieve hole size is 2 to 2.2 times the separation particle size, and the maximum is not more than 3 times; for vibrating screens, for medium particle size screens, the sieve hole size is 1.2 times the separation particle size; for coarse particle screens, the sieve hole size is 1.05 times the separation particle size; for probability screens, the sieve hole size is generally 2 to 2.5 times the actual separation particle size.

(5) Determine whether to select a double-layer or multi-layer screen. When the particle size range of the screened material is wide When a double-layer screen is used as a single-layer screen, the processing capacity of the screening machine can be improved, the lower screen can be protected, and the service life of the lower screen can be extended. The selection of the upper screen hole size of the double-layer screen should generally be determined according to the particle size characteristics of the feed. According to the amount of underscreen on the upper screen, the material particle size equivalent to 55~65% of the original feed amount is used as the screen hole size.

Note that when the underscreen particle content in the raw material exceeds 50%, there are many difficult-to-screen particles, there is a lot of sticky mud in the material, and the moisture content is high, try to avoid choosing a double-layer screen as a single-layer screen.

(6) Determine the effective working area of ​​the screen. The screening area calculated according to the production process requirements is the effective area of ​​the screen, and the specification of the screen is the nominal area of ​​the screen. For medium-sized materials For vibrating screens, the effective screening area should be 0.8~0.85 times the nominal area of ​​the screen. Of course, this is closely related to the opening rate of the screen holes on the screen surface.

(7) Heavy vibrating screens are mostly used for materials above 200mm; circular motion screens are mostly used for materials above 10mm; linear vibrating screens and high-frequency vibrating screens are mainly used for desludging, dehydration and grading.

(8) When conditions permit, seat screens should be given priority for easy maintenance. When a hanging screen must be selected, the hoisting height should be minimized to reduce the swing range of the vibrating screen and facilitate production and operation.

When choosing screening equipment, not only one reason should be considered, but also various factors should be fully considered to ensure that the equipment suitable for your working conditions is selected.