General
Screen blinding always happends when the screen mesh openings are blocked or closed by the material which is being screened. Near size particles become trapped or build up on the wires effectively blocking the screen openings preventing further material from passing through the screen. And some blinding because the material features such misture and stickiness, and some because there are too many fabric, This is a common screening problem which is easily fixed with screen cleaning devices. following will review the most common methods of screen deblinding.
1.BALL TRAYS
Rubber or other spring balls are the second most utilized screen cleaning method, but can only be used for dry screening. The rubber balls are generally 20mm-50mm diameter and are supported by a second coarser mesh two inches below the classifying screen mesh. Higher vertical separator motion is required to activate the ball cleaning action because the balls must be thrown up against the bottom of the screen, in this case ,the rectangular gyratory screener have long stroke and strong force which could let ball jump.
2.SLIDERS
The most common self cleaning device is the “SLIDER”. Slider Rings are loose rings which slide directly beneath the screen surface on a slider support surface, normally a perforated metal plate. The rings are bounced vertically into the screen mesh by the vertical motion of the separator as they travel radially around the screen. The sliders are activated by the motion of the separator with out additional driving force
3.SANDWICH SCREENS
Sandwich screens are made by bonding a classifying mesh to the top of the screen tension ring and a coarser support screen mesh to the bottom of the ring. This creates a sandwich with screen cleaning devices floating between meshes. This sandwich construction improves cleaning action, decreases maintenance costs, and decreases noise levels.
4.TOP SIDE ROTARY BRUSHES
The top side rotary brushes are exceptional for clearing fibrous materials which tend to mat on top of the screen and block the mesh openings. The rotary brushes move around the screen diameter propelled by the vibratory motion of the separator, no additional driving motors are required. The brushes ball up the fibrous mat above the screen to expose screen the openings, the fiber balls are then discharged from the top of the screen and out the spout.
5.WATER SPRAYS
Water sprays clear screen mesh openings, help eject solids, and keep slurries from drying out and building up inside separators. Another spray advantage is there is no contamination from slider, ball, or brush materials. The disadvantages of liquid sprays are cost and potential dilution of products.
6.Metal percussion
This is method is mainly adopt on the rotary screener, the Metal hammer rotate follow with the rotary screen drum, and the hammer knock on drum casing periodly.
