The screen mesh is an important part of the vibrating screen. The correct selection and use of the screen directly determine the gradation and quality of the product.
This paper lists the requirements of the high-quality screen, the main causes of mesh plugging, and how to solve vibrating screen mesh hole clogging.
You may interest in buy a vibrating screen, JXSC engineer helps select suitable screen type, mesh material, hole type, etc.
High-quality screens requirements
(1) Material – special wear-resistant steel wire.
—-chemical composition of C and Mn should be high enough, while Si, P and S should be as low as possible.
—-In physical processing, it is necessary to have the uniformity of fine structure, heat treatment is required to reach the Sorbite structure, and it is better to heat it to the refined austenite structure after tempering to temper to the finer troostite structure. Thus to ensure that the material has high strength, good torsion value and fatigue resistance after processing.
(2) Reasonable weaving form
The wire must be tightly woven and not loose.
(3) The outer dimensions and the shape of the edging must be properly matched with the tensioning plates and screen frames on the screen.
(4) The screen is flat and parallel on both sides.
(5) Reasonableedging form is conducive to adjust the tension of the screen.
Common causes of screen plugging
Screen plugging is one of the common faults in the operation of vibrating screens. The shape of the sand and gravel, the critical particle size of the mesh, the thickness of the wire mesh, and the shape of the mesh are all factors that may cause the mesh to block.
(1) It contains a large amount of crushed rock whose particle size close to the screen mesh. During the screening process, those crushed materials can not be smoothly screened in the mesh to cause blockage, which is called critical plugging.
(2) Too many flaky shape materials. The flaky shape material cannot be sieved smoothly, and as the flaky shape material piles up, it hinders the screening of other materials, causing plugging.
(3) The sieving material has high moisture content and contains viscous mud.
When the material contains much mud, the fine-grained material and mud is easy to agglomerate due to the intervention of water, and some soil is bonded to the sieve surface, making the material difficult to be sieved, resulting in plugging.
(4) Screen mesh and steel wire diameter
The practice has proved that the same mesh, too thick steel wire will cause a significant increase in the probability of plugging.
(5) Mesh shape
Most of the screens are square holes, the small mesh use anti-blocking mesh. If the mesh is still severely blocked, the rectangular hole can also be used under the premise of without affecting the particle size.
Change the screen mesh structure
(1) Rectangular holes
Under the premise of meeting the granularity requirements, change the screen mesh structure.
Use rectangular holes with a certain proportion. For example, adjust the original 3.5mm*3.5mm mesh to a 3.5mm*4.5mm rectangle.
It should be noted that the different direction of the mesh which will affect the screening efficiency and the service life of the screen to a certain extent.
(2) Use a diamond-shaped hole anti-blocking screen. This kind of screen is made of the same two adjacent strips with a slight vibration and has a better anti-blocking effect.
(3) Triangle hole anti-blocking screen. Among the two adjacent sieve bars, one is a static sieve bar and the other is a movable sieve bar.
The planar two-dimensional sieve fixed hole is changed to the three-dimensional changeable mesh.
The secondary vibration generated by the adjacent sieve bars in the random vibration is used to realize the effective vibration difference, make the mesh hole keep continuous change during the screening. Thereby eliminating the fixed critical particle size.
The practice has shown that the screening efficiency of the triangular mesh is about 30% higher than that of the fixed mesh, which greatly reduces the clogging of the mesh.
(4) Performance comparison of three mesh shapes
Square hole, rectangular hole, and triangular hole 3 type sieve hole.
|Screen mesh shape||Square||Rectangular||Triangular|
|Advantage||high accuracy of material particle control||Increased screening efficiency, less clogging than the square hole||No blocking, high screening efficiency|
|Disadvantage||Easily blocked and affect the screening efficiency. Especially when the mesh is below 8mm, the mesh hole clogging is obvious.||Can only be used without affecting production requirements or where don’t require a high standard of particle||Replace the square mesh screen should be correctly converted in advance|
Control the shape of the material
In the stone crushing line, the content of the needle-shaped stone should be as low as possible to prevent the screen from being clogged.
Most of the stone plants use two crushing stages. For the primary crushing, the jaw crusher is easy to produce flaky shape rock. The secondary crusher often uses impact crusher. In order to reduce the flaky-shaped rock ratio, the first crushing size should not be too small.
Reasonably adjust the tension of the screen
Reasonable adjustment of the tension of the screen is an effective method to reduce the hole plugging. The reasonable tensioning force causes the screen to produce a slight secondary vibration with the support beam, thus effectively reducing the occurrence of plugging.
JXSC custom vibrating screen material and mesh type for different applications.