Vibrating screens play a crucial role in industries such as mining, aggregate processing, and material classification by efficiently separating materials of different sizes. However, screen blockage is a common issue that reduces screening efficiency, increases downtime, and raises maintenance costs.

Blockage occurs when materials such as wet, sticky, or irregularly shaped particles adhere to the screen mesh, clogging openings and restricting material flow. Factors such as moisture content, screen design, and improper vibration settings contribute to this problem.

Vibrating screen blockage prevention method

Vibration screen blockage is a common issue that reduces efficiency and throughput. Here’s a breakdown of methods to prevent it, categorized by approach:

1. Material Preparation & Handling:

Screening Beforehand: If possible, pre-screen the material with a coarser screen to remove oversized particles or debris that might cause blockage in the main screen.

Proper Material Drying: Excessive moisture is a primary culprit for blockage, especially with fine materials. Dry the material thoroughly before screening. Methods include:

Air Drying: Spreading the material thinly and allowing air circulation.

Oven Drying: Controlled temperature drying in an oven.

Fluid Bed Drying: Efficient for particulate materials, using heated air to fluidize and dry the particles.

Infrared Drying: Uses infrared radiation to heat and dry the material.

Material Conditioning: Introduce additives to the material to improve its flow characteristics. Examples include:

Anti-caking agents: Prevent agglomeration of particles.

Flow enhancers: Reduce friction and improve material movement.

Consistent Material Feed Rate: Avoid surges of material onto the screen. A consistent, controlled feed rate allows the screen to process the material effectively. Use feeders like:

Vibratory Feeders: Provides even and adjustable material flow.

Screw Feeders: Good for controlled metering of powders and granules.

Belt Feeders: Suitable for handling a wide range of materials.

2. Screen Design & Selection:

Appropriate Mesh Size: Choose a mesh size that’s suitable for the particle size distribution of your material. Too small a mesh increases the risk of blinding (where particles get lodged in the openings).

Screen Material: Select a screen material that resists wear, corrosion, and abrasion from the material being screened. Common materials include:

Stainless Steel: Durable and resistant to corrosion.

High Carbon Steel: Strong and wear-resistant, but prone to rust.

Polyurethane: Abrasion-resistant and flexible.

Nylon: Good for handling abrasive materials and materials that tend to stick.

Screen Type: Different screen types are better suited for different materials and applications:

Woven Wire Mesh: Common and versatile, but can be prone to blinding.

Perforated Plate: Stronger and less prone to blinding than woven wire mesh, but less efficient for separating fine particles.

Polyurethane Screens: Excellent abrasion resistance and self-cleaning properties. Can be molded into complex shapes for specialized applications.

Wedgewire Screens: Provides a high open area and reduces blinding. Good for handling wet or sticky materials.

Anti-Blinding Screen Designs:

Bouncing Balls/Rings: Small balls or rings placed under the screen that bounce and strike the screen mesh, dislodging particles.

Ultrasonic Vibration: Imparts high-frequency vibrations to the screen mesh, preventing particles from sticking.

Air Knives/Air Blasters: Use compressed air to blow away particles from the screen surface.

Flexible Fingers/Tines: Flexible elements that continuously agitate the screen mesh.

3. Vibration Screen Operation & Maintenance:

Proper Tensioning: Ensure the screen is properly tensioned. Loose screens vibrate excessively and can lead to blinding. Overly tight screens can be damaged.

Optimal Vibration Frequency & Amplitude: Adjust the vibration frequency and amplitude to suit the material being screened.

Higher Frequency: Better for fine particles.

Higher Amplitude: Better for coarser particles and materials that tend to clump. Too much amplitude can damage the screen.

Regular Cleaning: Clean the screen regularly to remove accumulated particles. Methods include:

Brushing: Manual brushing to remove surface buildup.

Water Washing: Washing with water and potentially detergents. Ensure the screen is compatible with the cleaning agents.

Compressed Air Cleaning: Blowing away particles with compressed air.

Regular Inspection: Inspect the screen for damage (tears, holes, loose wires). Replace damaged screens promptly. Check bouncing ball systems or other anti-blinding mechanisms for wear and tear.

Dust Collection/Containment: Implement a dust collection system to remove airborne particles that can settle on the screen and contribute to blockage.

4. Environmental Control:

Humidity Control: In humid environments, consider using dehumidifiers to reduce the moisture content of the air, which can help prevent material from sticking to the screen.

Temperature Control: Extreme temperatures can affect the flowability of some materials. Maintaining a consistent temperature can help prevent blockage.

Key Considerations for Choosing a Method:

Material Properties: Particle size, shape, moisture content, stickiness, abrasiveness.

Screen Size & Type: The type of screen and its dimensions will influence the available options.

Throughput Requirements: How much material needs to be screened per hour?

Budget: Some methods, like ultrasonic vibration, are more expensive than others.

Maintenance Requirements: How much maintenance is required for each method?

By carefully considering these factors and implementing the appropriate methods, you can significantly reduce vibration screen blockage, improve efficiency, and extend the lifespan of your equipment.

A linear vibrating screen is a screening machine that uses vibration to separate materials based on size. It operates using a linear motion, which is generated by two counter-rotating vibratory motors or exciters. These vibrations cause the material to move forward while allowing smaller particles to pass through the screen mesh, effectively sorting and classifying materials. The technical parameters of a linear vibrating screen can be quite extensive, depending on the manufacturer and specific application.

Linear vibrating screen technical parameters

1. Mechanical and Dimensional Parameters:

Screen Size (Length x Width): This is the active screening area, often in meters (m) or millimeters (mm). It’s crucial for determining the throughput capacity of the screen. e.g., 1.5m x 3m, 2m x 4m.

Overall Dimensions (Length x Width x Height): Total physical size of the machine, including the frame, motor, and other components. Important for space planning.

Weight: The total weight of the machine in kilograms (kg) or metric tons (t). Relevant for transportation and installation considerations.

Number of Decks: How many screening surfaces are stacked on top of each other. Single-deck screens perform a single separation, while multi-deck screens can perform multiple separations in one pass.

Deck Inclination Angle: The angle of the screen deck relative to the horizontal. This influences material flow rate and screening efficiency. Typically a small angle (e.g., 5-10 degrees).

Mesh Size (Aperture Size): The size of the openings in the screen mesh, in millimeters (mm) or micrometers (µm). Determines the cut size (separation size). Each deck in a multi-deck screen will have a different mesh size.

Mesh Material: The material used for the screen mesh, such as stainless steel (common grades: 304, 316), woven wire cloth, perforated plate, polyurethane, or rubber. The choice depends on the material being screened and the required durability.

Frame Material: The material used for the screen frame, typically carbon steel (with coating for corrosion resistance) or stainless steel.

Screening Area (Total): The total active area of all screening decks combined.

2. Vibration Parameters:

Vibration Frequency: The number of vibration cycles per second, measured in Hertz (Hz) or cycles per minute (CPM). Frequency affects the material’s agitation and movement on the screen.

Vibration Amplitude (Stroke): The distance the screen deck moves during each vibration cycle, in millimeters (mm). Amplitude influences the material’s throw and the screening rate. Often adjustable.

Excitation Force: The force generated by the vibratory motor to drive the screen, measured in Newtons (N) or kilonewtons (kN). It’s related to the motor’s power and the eccentric weight.

Vibration Direction: The direction of the vibratory motion, which is typically linear (straight line) for linear vibrating screens. The angle of the linear motion relative to the screen surface can be a factor.

Vibrator Type: The type of exciter used to generate the vibrations. Common types include:

Vibratory Motors (Unbalanced Motors): Two motors with eccentric weights rotating in opposite directions. This is the most common type.

Electromagnetic Vibrators: Used for smaller screens.

Mechanical Vibrators: Driven by belts and pulleys.

3. Operational and Performance Parameters:

Capacity/Throughput: The amount of material the screen can process per unit of time, typically measured in metric tons per hour (t/h) or kilograms per hour ( kg/h ). Capacity is heavily dependent on the material being screened, its particle size distribution, and the screen parameters.

Screening Efficiency: The percentage of material smaller than the mesh size that passes through the screen. A higher efficiency means less of the fine material ends up in the oversize product. Often expressed as a percentage (e.g., 95%).

Separation Size (Cut Size): The particle size that is being separated by the screen. Ideally, all particles smaller than this size pass through, and all particles larger than this size are retained on the screen. It’s determined by the mesh size.

Feed Size (Maximum Particle Size): The maximum size of the particles that can be fed into the screen without causing damage or blockages.

Feed Rate: The rate at which material is fed onto the screen, which directly impacts the screen’s performance and capacity.

Moisture Content (Maximum): The maximum allowable moisture content of the feed material. Excessive moisture can cause clogging and reduce screening efficiency. Expressed as a percentage.

Power Consumption: The electrical power required to operate the screen, measured in kilowatts (kW).

Noise Level: The noise generated by the screen during operation, measured in decibels (dB). Important for workplace safety.

Dust Emission: The amount of dust released during screening. This is important for environmental considerations, and often requires dust collection systems.

4. Motor Parameters (for Vibratory Motor-Driven Screens):

Motor Power: The power of the vibratory motor(s), in kilowatts (kW) or horsepower (HP).

Motor Speed: The rotational speed of the motor(s), in revolutions per minute (RPM).

Voltage and Frequency: The electrical power requirements (e.g., 380V/50Hz, 440V/60Hz).

Insulation Class: The temperature rating of the motor’s insulation (e.g., Class F, Class H).

Protection Class: The motor’s protection against dust and water ingress (e.g., IP54, IP65).

Number of Poles: Determines the synchronous speed of the motor.

5. Additional Features and Options:

Spray System: Water or liquid spray nozzles to help separate sticky or dusty materials.

Dust Cover: Enclosure to minimize dust emissions.

Screen Cleaning System: Devices to prevent screen blinding (blockage), such as bouncing balls, ultrasonic vibration, or rotating brushes.

Explosion-Proof Design: For use in hazardous environments where flammable materials are present.

Variable Frequency Drive (VFD): Allows for adjustable vibration frequency and amplitude.

Remote Control: For convenient operation and monitoring.

Material of Construction (Contact Parts): Specifies the materials used for parts that come into contact with the screened material (e.g., stainless steel for food-grade applications).

Lubrication System: Details of the lubrication method and required maintenance.

Importance of Specifying Parameters:

It’s crucial to specify all relevant technical parameters when selecting or designing a linear vibrating screen to ensure it meets the specific requirements of the application. Incorrect parameters can lead to:

Inefficient Screening: Poor separation of materials.

Low Throughput: Unable to process the required amount of material.

Equipment Failure: Overloading the screen or using it with unsuitable materials.

Increased Maintenance Costs: Frequent repairs due to improper operation.

Unsafe Operation: Noise, dust, and potential hazards.

When requesting information from a manufacturer, be prepared to provide details about the material you intend to screen, the desired throughput, and the required separation size. This will help them recommend the most suitable screen and provide accurate technical parameters.

Vibrating screen is a kind of mechanical equipment used to screen different particle size substances, which is composed of screen mesh and vibrator. It vibrates the screen mesh, making the larger particle size substances fall in the settling area under the screen mesh, leaving the smaller particle size substances, so as to achieve the purpose of separation. Vibrating screen is mainly divided into linear vibrating screen, circular vibrating screen and high frequency vibrating screen. It mainly includes the following characteristics:
1. It adopts high-frequency and high-amplitude vibration mode to screen different materials to different degrees to achieve the required precision, improve screening efficiency and save time.
2. It can deal with powder, granule, liquid and other materials to meet the precise screening needs of different industries.
3. It can realize the automatic setting of screening time and frequency, simplifying the operation process. Realize remote operation and monitoring, reduce manual intervention.

These characteristics of the vibrating screen so that it has a place in many applications, in each field it plays a very important role, the following mainly introduces the application of the three areas of the scene:
1. Food industry: As food in the production process involves screening and selection of materials, this process is very cumbersome, it is difficult to improve the efficiency of manpower alone, and thus the food vibrating screen came into being, and has become an indispensable piece of machinery and equipment in the production process of many food industries. Food vibrating screen is mainly used for screening various food materials and finished products. Using this equipment, we can not only improve the screening efficiency and precision, but also to ensure the quality and integrity of food.
2. Pharmaceutical industry: the pharmaceutical industry has an extremely important impact on people’s health, so the requirements for vibrating screens in the pharmaceutical industry will be higher, and the materials used should strictly meet the corresponding production standards. In the pharmaceutical industry, the vibrating screen can be used to process the raw materials in advance, such as screening, cleaning and drying of medicinal materials; it can also be used for the screening of intermediate products, such as the grading of powder and tablets and dust removal; it can also be used for the quality control of the finished products, such as the inspection of the drugs before packaging.
3. Building materials industry: in the building materials industry, a large amount of material screening is usually required, and low energy consumption equipment can significantly reduce the waste of resources and environmental load. Through the screening effect of vibrating screen, particles of different sizes in raw materials can be effectively separated to ensure the uniformity and stability of the products. In addition, vibrating screen also plays an important role in the recycling of construction material industry, which can realize the recycling of resources, reduce environmental pollution and achieve sustainable economic development.

To sum up, as an indispensable equipment in the development of modern science and technology and industrial production, vibrating screen has been widely used in food, medicine, building materials and other fields with its high efficiency, personalization and automation. And with the continuous development of economic construction and scientific research, it is believed that there will be more vibrating screens to meet different needs, improve production efficiency and product quality. Enterprises should choose the corresponding type of vibrating screen according to different application scenarios, and pay attention to timely maintenance to ensure the normal operation and use of the equipment cycle.

Improving the screening capacity of a horizontal linear vibrating screen involves a multifaceted approach, addressing various aspects of the machine and its operation. Here’s a breakdown of key areas to focus on.

Improve horizontal linear vibrating screen screening capacity

1. Screening Parameters

Frequency and Amplitude:

Increase Frequency: Higher frequency generally leads to better stratification and faster particle movement, thus increasing capacity. However, it can also increase screen wear. Experiment to find the optimal balance.

Adjust Amplitude: Increasing amplitude can improve throughput but may also cause material to bounce excessively, reducing screening efficiency. Fine-tuning is crucial based on the material characteristics.

Consider Variable Speed Drives (VSD): Allow you to adjust both frequency and amplitude on the fly to optimize for different materials or conditions.

Screen Deck Angle:

Typical Angle: Horizontal screens often have a very slight incline (1-5 degrees) to assist material flow.

Fine-tuning: Experiment with small angle adjustments to optimize material transport speed and prevent overloading at the feed end.

Stroke Direction and Angle:

Linear Motion: Horizontal screens use linear motion, typically angled 45 degrees to the flow direction.

Adjust Angle: Slight variations in the stroke angle can influence material stratification and throughput. Experiment to find the best angle for your specific material.

2. Screen Media:

Mesh Size and Type:

Proper Selection: Choose the appropriate mesh size based on your desired separation.

Optimize for Material: Consider the shape and size distribution of the material being screened. Different mesh types (e.g., woven wire, polyurethane, rubber) have varying open areas and wear characteristics, which impact capacity.

Consider Self-Cleaning Designs: Anti-blinding mesh designs, like piano wire or slotted screens, can prevent screen blockage and maintain capacity.

Screen Tension:

Proper Tension: Ensure screens are properly tensioned. Loose screens will vibrate improperly, leading to decreased efficiency and capacity.

Regular Checks: Regularly check and maintain screen tension as it can change over time.

Screen Deck Area:

Larger Surface: A larger screen deck naturally offers higher capacity.

Evaluate Existing Deck: If space allows, consider upgrading to a larger screen deck.

3. Material Feeding and Distribution:

Even Feed Distribution:

Controlled Feed: Ensure material is fed evenly across the entire width of the screen to prevent overloading in certain areas.

Feeders: Use appropriate feeders (e.g., vibratory feeders, belt conveyors) to control the feed rate.

Distributors: Implement devices like spreaders or diverters to distribute the feed evenly.

Feed Rate Control:

Optimized Feed Rate: Overfeeding or underfeeding can reduce capacity. Experiment to find the optimal feed rate for your material and screen setup.

Monitoring: Monitor the material bed depth on the screen. Too deep can hinder screening, while too shallow might not allow for efficient separation.

Material Preparation:

Pre-screening: Removing oversized material before it reaches the main screen can improve throughput and reduce wear.

De-agglomeration: If material clumps together, consider using de-agglomeration techniques (e.g., tumbling, air cannons) before screening.

4. Screen Machine Maintenance and Condition:

Regular Inspections: Regularly inspect all components, including bearings, springs, and screen frames, for wear and damage.

Lubrication: Ensure proper lubrication of all moving parts to reduce friction and ensure optimal performance.

Screen Frame Integrity: Ensure the screen frame is structurally sound and free from cracks or warping.

Proper Installation: Ensure the screen is properly installed and leveled on a stable foundation to minimize vibrations and ensure consistent performance.

5. Environmental Factors:

Temperature: Extreme temperatures can affect material properties and screen performance.

Moisture Content: High moisture content in the feed material can cause blinding and reduce capacity.

Dust Control: Implement dust suppression measures to prevent dust buildup, which can affect screen performance.

Key Steps for Improvement:

Analyze Your Current Performance: Understand your current screening capacity and bottlenecks.

Identify the Limiting Factors: Pinpoint the specific areas that are hindering capacity.

Experiment with Adjustments: Systematically test different parameters and solutions.

Monitor and Track Results: Collect data to determine the effectiveness of each change.

Implement Optimal Settings: Once the best settings are identified, implement them consistently.

Important Considerations:

Material Characteristics: The properties of the material being screened (e.g., size distribution, shape, moisture content) significantly affect screening capacity.

Cost-Benefit Analysis: Consider the costs associated with upgrades and adjustments compared to the potential benefits.

Safety: Ensure all modifications and adjustments are performed safely and in accordance with manufacturer guidelines.

By systematically addressing these areas, you can significantly improve the screening capacity of your horizontal linear vibrating screen, leading to increased productivity and efficiency. Remember that optimizing a screen is often an iterative process involving experimentation and data analysis.

The screening performance of a vibrating screen is influenced by various factors, including operational parameters, screen design, and material properties. Optimizing these factors can significantly improve screening efficiency and throughput. Here’s a breakdown:

Factors Affecting Screening Performance

1. Material Properties

Particle Size Distribution:

A wide size distribution may lead to reduced efficiency, as smaller particles can block the screen openings.

Particle Shape:

Irregularly shaped particles are less likely to pass through the screen compared to spherical particles.

Bulk Density:

High-density materials may require more energy for efficient separation.

Moisture Content:

Wet materials tend to clump together, reducing screening efficiency and causing screen blinding.

Material Flowability:

Poor flowability can lead to uneven distribution across the screen surface.

2. Screen Design

Screen Aperture Size and Shape:

Apertures that are too small or have an inappropriate shape can lead to clogging or poor separation.

Screen Inclination:

The angle of the screen affects the travel speed of the material and the likelihood of particles passing through the screen.

Number of Decks:

Multi-deck screens can separate materials into multiple size ranges but may decrease efficiency due to increased complexity.

Vibrating Frequency and Amplitude:

Higher frequencies and optimal amplitudes improve material stratification and throughput.

3. Operational Parameters

Feed Rate:

Excessive feed can overload the screen and reduce efficiency.

Material Distribution:

Uneven distribution across the screen surface decreases separation efficiency.

Vibration Direction and Pattern:

Linear, circular, or elliptical vibration patterns affect material movement and screening performance.

Screening Time:

Insufficient time for particles to pass through the screen results in lower efficiency.

4. Environmental Factors

Ambient Conditions:

High humidity or dust levels can affect material properties and the screen’s performance.

Operating Temperature:

Extreme temperatures can impact material behavior and machine performance.

5. Maintenance and Wear

Screen Surface Condition:

Worn or damaged screens reduce separation efficiency and may cause contamination.

Proper Tensioning:

Loose or improperly tensioned screens can lead to uneven vibrations and reduced efficiency.

Lubrication and Component Wear:

Poor lubrication or worn components (e.g., bearings) can negatively impact vibration consistency.

Tips to Improve Screening Performance

Optimize Screen Design:

Choose the right aperture size and shape for the material being screened.

Adjust the screen angle and vibration parameters to suit the application.

Control Material Properties:

Pre-dry or condition materials to reduce moisture and prevent clumping.

Implement pre-screening processes to remove oversized particles.

Regulate Operational Parameters:

Maintain consistent feed rates and ensure even material distribution.

Match vibration patterns to the material characteristics and screening requirements.

Regular Maintenance:

Inspect and replace worn screens and components.

Regularly clean screens to prevent clogging and blinding.

Use Auxiliary Equipment:

Install feeders or distributors to ensure uniform material flow.

Apply anti-clogging devices or ultrasonic technology to improve screening efficiency for fine or sticky materials.
By carefully considering and optimizing these factors, you can maximize the efficiency, accuracy, and throughput of vibrating screens in various applications.