How to solve the problem of filter screens getting clogged?

Filter screen clogging is indeed a common and troublesome problem. Effective solutions and prevention hinge on accurately identifying the type of clogging and taking targeted measures. Below is a summary of common causes and corresponding solutions.

Identifying the Type of Clogging

First, quickly determine the type of clogging your screen has. This helps in quickly locating the problem:

Dry Clogging/Bridging: This typically occurs when processing dry, angular, or unevenly sized materials. The material forms an arch above the screen openings, getting stuck in or blocking the openings, preventing passage.

Wet Clogging/Screw Clogging: Commonly seen when processing materials containing moisture, oil, or sticky components (such as sugar or starch). These components adhere to the screen wires or accumulate and harden in the openings.

Pore Clogging: When the material contains particles slightly larger than the screen openings, or when the material has an irregular shape (such as flakes or fibers), it easily gets stuck in the screen openings, causing clogging.

Static Clogging: For dry, lightweight powders (such as plastic powder or flour), static electricity is easily generated during sieving, causing the powder to adhere to the screen.

Targeted Solutions

Depending on the cause of clogging, adjustments can be made to the material, the screen itself, and the equipment operation.

Optimizing Material Condition

Controlling Humidity and Viscosity: If the material has excessive moisture or oil content, consider drying (using a dryer) or degreasing (washing, centrifugation) before screening. For hygroscopic materials, pay attention to ambient humidity or implement sealing measures.

Handling "Critical Particles": If there are too many "critical particles" in the material that are close to the screen aperture size, they can easily clog the apertures. Try pre-crushing the material to reduce their size.

Improving Flowability: For electrostatic adsorption caused by lightweight powders, or where permissible, adding a very small amount of a flow aid (such as food-grade talc or silica powder) or antistatic agent that does not affect the material properties can help improve material flowability and reduce clogging.

Choosing the Right Screen

Screen Material and Aperture Type: For materials prone to clogging, consider using screens with better anti-clogging performance. For example, polyurethane screens (especially those with trapezoidal or corrugated designs) are wear-resistant and elastic, with larger openings at the top and smaller openings at the bottom, allowing for high material throughput and easy ejection even if stuck. For sticky materials, rubber screens are also a good choice due to their good elasticity and resistance to sticking.

Screen Hole Shape: Choose the appropriate hole shape for different material shapes. For example, for fibrous or flaky materials, rectangular or narrow-slit screens may be less prone to clogging than traditional square or round holes.

Wire Diameter and Aperture Ratio: While maintaining screen strength, choosing a screen with a relatively fine wire diameter can increase the aperture ratio (effective screening area) and reduce the risk of clogging.

Adjusting Equipment and Operating Parameters

Controlling Feeding: Avoid feeding too much or too forcefully at once. Material should be continuously, evenly, and in appropriate amounts spread on the screen surface to prevent excessive accumulation that could cause the bottom layer of material to clog the screen or become stuck.

Optimizing Vibration Parameters: Adjust the amplitude and frequency of the vibrating screen. Generally, for fine powders, sticky materials, or materials containing moisture, a high-frequency, low-amplitude setting is more effective.

Maintain screen tension: Ensure the screen is taut and level during installation. Proper tension helps generate slight secondary vibrations, effectively reducing clogging.

Utilize screen cleaning devices: Ensure screen cleaning devices (such as bouncing balls) are functioning properly, are sufficient in number, and are not worn or aged. For fine screens, consider installing an ultrasonic screen cleaning system,

which effectively prevents adhesive clogging through high-frequency vibration.

Establish good cleaning and maintenance habits:

Clean promptly: Clean the screen immediately after each use while the material is still wet. For industries such as food processing, use a soft brush, food-grade detergent, and running water for thorough cleaning; perform deep disinfection periodically if necessary.

Regular inspection: Regularly inspect the screen for wear, deformation, or rust; replace it promptly if problems are found.

Emergency handling and fundamental prevention:

When the screen is clogged, stop the machine and safely shut it off. Clean it with a soft brush, compressed air, or water (if available). For stubborn blockages, soaking or gentle tapping may be necessary (be careful to protect the screen).

Most importantly, adopt a "prevention-first" approach. After each blockage, analyze the root cause and optimize the system by considering factors such as the material, the screen, and equipment operation.

If the problem is complex, consult a professional screen supplier or equipment manufacturer.