Material screening is a crucial step in pulping, and it’s used not only in pulp production but also in screening processes in mines and coal plants. As a component of vibrating screens, the structure and performance of the vibrating screen plate significantly impact the particle size and quality of the screened material.

Common Screen Plate Structures

According to the shape and structure of the screen plate, common types include: stepped screen plates (comb-shaped screen plates), bar-shaped screen plates, slotted screen plates (flat strips, straight strips, etc.), and flat screen plates (herringbone holes, round holes, square holes, etc.). The following is a comparative analysis based on their structure and performance.

Stepped Screen Plates

Composed of several overlapping screen bars, arranged in a staggered, inclined manner with a certain gradient, they offer good screening efficiency and are not easily clogged. They are typically made of polyurethane. Due to their excellent wear resistance, oil resistance, and hydrolysis resistance, they can significantly reduce equipment weight, lower equipment costs, extend service life, and operate with low noise. These screen plates are widely used in vibrating screens in mining, metallurgy, and coal industries. (In addition, there are screen plates made of metal.)

Bar Type Screen Plate

Composed of a set of parallel steel bars, the bars have various cross-sectional shapes (circular, trapezoidal, etc.). The width of the gap between the bars determines the screen aperture size. This type of screen plate is typically used in heavy-duty vibrating screens. The screen aperture size is generally 50mm or larger, with an opening rate of approximately 50% to 60%.

The high-frequency tuning fork bars in the screen plate generate secondary high-frequency vibrations when the screen plate is working, which increases the material speed, accelerates the settling of particles on the screen surface, and causes small particles that have already contacted the screen surface to move laterally towards the screen holes, thereby increasing the pass rate of the screen holes. This type of screen plate has a certain amount of moisture and sticky substances, which are shaken off by its high-frequency self-vibration, making it less likely to stick to the screen bars and cause blockage. It is more effective when processing sticky or fibrous materials.

Slotted Screen Plate

It consists of a sieve surface, transverse strips or branches, and a frame. The structural forms include welded and woven types. The screen slot size is around 0.5mm, and the opening ratio is about 15%-25%. This type of screen plate has certain advantages, such as a high opening rate and less clogging of the screen holes. However, it also has certain disadvantages. The screen plates and bars are generally made of spring steel, which has low hardness and a short service life.

Flat Screen Plates

These are typically perforated steel plates, about 5-8mm thick, made by drilling or punching. They are structurally robust, rigid, and have a long service life. However, they have a relatively low opening ratio and are generally used for screening medium-sized materials. Flat screen plates can be further categorized into: round hole, square hole, herringbone hole, and wire-woven screen plates.

Round Hole Screen Plates

These have a small opening ratio and are lightweight, making them suitable for screening materials with small particle size and high moisture content.

Square Hole Screen Plates

Compared to round hole screen plates, they offer a good opening ratio and are lightweight, reducing screen clogging when processing materials with high moisture content. However, this type of screen plate is only suitable for applications where the screening requirements are not particularly stringent.

Herringbone Screen Plates and Wire Mesh Screen Plates

Herringbone screen plates are suitable for screening finer material particles. Wire mesh screen plates are lightweight and have a high open area ratio (over 80%). These screen plates have a certain degree of elasticity and vibrate at high frequency, effectively removing fine particles adhering to the wires and improving screening efficiency. However, its drawback is that it has a relatively short lifespan.

Material properties, Different structures and materials of screen plates have a certain impact on the screening performance and efficiency of vibrating screen.