The deviation of material on a linear vibrating screen can occur for several reasons, affecting the efficiency of the screening process. When the material does not flow uniformly across the screen, it can lead to improper screening, clogging, and reduced performance.

Linear vibrating screen material deviation

1. Uneven Loading of Material

Cause: If the material is not fed uniformly across the width of the screen, one side may have more material than the other, leading to uneven distribution.

Solution: Ensure the material is fed evenly across the entire width of the vibrating screen. This can be achieved by adjusting the feeding mechanism, such as using a properly sized feeder or installing a distributor.

2. Imbalance of the Vibrating Motors

Cause: Linear vibrating screens typically use dual motors that must operate in sync. If one motor is running at a different speed, amplitude, or direction than the other, it can create an imbalance in vibration, causing material to shift to one side.

Solution: Check the alignment, speed, and angle of both motors to ensure they are synchronized and generating equal force. Correcting the imbalance will restore uniform material flow.

3. Incorrect Motor Position or Angle

Cause: The installation angle of the vibrating motors can influence the direction of material flow. If the angles of the motors are incorrect or inconsistent, the material may move in an undesired direction, causing deviation.

Solution: Adjust the angle of the motors according to the manufacturer’s guidelines. Most linear screens are designed to work with a specific motor angle to achieve optimal material flow.

4. Uneven Tension of the Screen Mesh

Cause: If the screen mesh is not tensioned evenly across the frame, it can cause parts of the screen to vibrate more or less than others. This can lead to uneven material distribution, with some areas allowing more material to pass through and others pushing it to the sides.

Solution: Check the tension of the screen mesh and adjust it evenly across the entire screen surface. Regular maintenance to keep the mesh properly tensioned can prevent this issue.

5. Damage or Wear to Screen Deck

Cause: If the screen deck has become damaged or worn out, it may not provide a consistent surface for the material to move across, leading to deviation or material accumulation on one side.

Solution: Inspect the screen deck for signs of wear, tears, or other damage. Replace or repair the screen deck as necessary to restore a smooth, uniform surface.

6. Inconsistent Vibrating Force

Cause: Vibrating force needs to be consistent across the entire screen. If there are inconsistencies due to motor misalignment, improper installation, or mechanical defects, the material may not flow uniformly, leading to deviation.

Solution: Ensure that the vibration force is consistent and evenly distributed by checking the alignment, motor power, and installation of the entire system.

7. Improper Slope Angle

Cause: The inclination or slope of the vibrating screen plays a key role in material flow. If the slope is too steep or too shallow, it can cause uneven material distribution.

Solution: Adjust the inclination angle of the screen according to the material characteristics and required processing speed. A properly inclined screen helps material flow evenly across the surface.

8. Vibration Damper Issues

Cause: Damper springs or shock absorbers are responsible for balancing the screen’s vibration. If one or more dampers are worn out or misaligned, the screen may vibrate unevenly, causing material to move erratically and deviate.

Solution: Inspect and replace any worn or damaged dampers. Properly balanced dampers are essential for maintaining uniform vibration and material flow.

9. Material Characteristics

Cause: The physical properties of the material, such as particle size, moisture content, or stickiness, can affect how it moves across the screen. Materials that are too wet, sticky, or have varying sizes may clump together and flow unevenly.

Solution: Consider pre-treating the material (e.g., drying or de-lumping) before feeding it onto the screen. You can also use appropriate screen mesh sizes or install a secondary screening system to handle materials with challenging characteristics.

10. External Vibrations or Environmental Factors

Cause: External vibrations from nearby equipment or structural movement can affect the operation of the vibrating screen, leading to material deviation.

Solution: Isolate the vibrating screen from external sources of vibration and ensure that the mounting structure is stable and not causing interference.

11. Frame or Structure Misalignment

Cause: If the screen’s frame or supporting structure is not properly aligned or leveled, it can lead to uneven vibration and material flow.

Solution: Check the alignment and leveling of the vibrating screen and its supporting structure. Adjust the leveling bolts or foundation to ensure the screen is properly positioned.

12. Improper or Worn Out Screen Media

Cause: The screen media (wire mesh or perforated plate) may become clogged, worn, or damaged, causing uneven material distribution.

Solution: Regularly clean and inspect the screen media. Replace worn-out or damaged media to ensure smooth material flow and proper screening performance.

Conclusion

To ensure that the material on a linear vibrating screen does not deviate, it’s crucial to maintain proper motor synchronization, uniform loading, screen tension, and correct installation angles. Regular inspections and maintenance are key to preventing material deviation and ensuring efficient screening performance.

Linear vibrating screens can be classified and categorized based on various criteria, including design, application, and operation.Here are some common models and classifications:

1. By Design:

Single Deck Screens: These have one screening surface and are used for simple classification tasks.

Multi-Deck Screens: Equipped with two or more screening surfaces, allowing for multiple size separations in one operation.

2. By Application:

Heavy-Duty Linear Screens: Designed for handling large and abrasive materials, typically used in mining and quarry applications.

Fine Screening Linear Screens: Used for smaller particle sizes, often in food, chemical, and pharmaceutical industries.

3. By Motion and Drive Type:

Electromechanical Linear Screens: Utilize electric motors and unbalanced weights to create linear motion.

Hydraulic Linear Screens: Use hydraulic systems for movement, which can be advantageous for certain applications.

4. By Material Handling:

Wet Linear Screens: Designed for applications where materials are processed with water or other liquids.

Dry Linear Screens: Suitable for dry materials and typically equipped with features to minimize dust.

5. By Screen Surface:

Mesh Screens: Traditional screens made from woven wire mesh for various particle sizes.

Perforated Plate Screens: Use metal plates with holes for larger particles, offering durability and easier cleaning.

6. By Size:

Standard Size Screens: Common dimensions used in general applications.

Custom Size Screens: Tailored dimensions to meet specific operational requirements.

Key Features to Consider:

Frequency and Amplitude: These can be adjusted to optimize performance for different materials.

Incline Angle: The angle of the screen can be adjusted to influence the flow and separation efficiency.

These classifications help users choose the right type of linear vibrating screen based on their specific needs and the characteristics of the materials being processed.

Vibrating screens used in coal mines are crucial for the efficient separation and sizing of coal and other minerals. Standards for these screens ensure their performance, safety, and reliability in harsh mining environments. Various standards and guidelines apply depending on the region and specific application. Here are key standards and considerations for vibrating screens in coal mines.

Vibrating screen standard for coal mines

Key Standards and Guidelines

ISO 17827 (International Standard):

• Description: Provides guidelines for the determination of the particle size distribution of coal by sieving.
• Application: Relevant for the design and testing of vibrating screens used for coal sizing.

ISO 9001 (Quality Management):

• Description: A general standard for quality management systems, applicable to manufacturers of vibrating screens.
• Application: Ensures that the design and production processes meet quality standards, leading to reliable and effective screening equipment.

ASME (American Society of Mechanical Engineers):

• Description: Provides various codes and standards related to mechanical equipment, including those that might apply to vibrating screens.
• Application: Ensures that the construction and operation of vibrating screens meet safety and performance requirements.

AIME (American Institute of Mining, Metallurgical, and Petroleum Engineers) Standards:

• Description: Includes guidelines specific to mining equipment, which may cover aspects related to vibrating screens.
• Application: Ensures that equipment used in mining operations, including vibrating screens, is suitable for the demanding conditions.

API (American Petroleum Institute):

• Description: Provides standards for equipment used in the petroleum and natural gas industries, which may include screening equipment.
• Application: Ensures that the vibrating screens meet performance and safety standards in related applications.

Design Considerations

Screen Material and Construction:

Material: Vibrating screens are typically constructed from high-strength steel or other durable materials to withstand the abrasive nature of coal and other mined materials.

Construction: Must be robust and designed to handle high loads and vibrations. This includes the use of reinforced frames and heavy-duty springs.

Screen Size and Capacity:

Size: Screens are available in various sizes and configurations to suit different throughput requirements and space constraints.

Capacity: The design must accommodate the volume of material to be processed without compromising performance.

Screen Type and Motion:

Type: Different types of vibrating screens include linear, circular, and elliptical motion screens. The choice depends on the specific application and material characteristics.

Motion: The motion of the screen affects the separation efficiency and capacity. Design parameters should be optimized for the material being screened.

Safety Features:

Guarding: Adequate guarding should be provided to prevent accidental contact with moving parts.

Emergency Stops: Emergency stop systems should be in place to allow for immediate cessation of operation in case of a malfunction or safety issue.

Maintenance and Accessibility:

Maintenance Access: Screens should be designed for easy access to components for maintenance and repairs.

Serviceability: Replaceable parts and easy-to-service components help minimize downtime.

Noise and Vibration Control:

Noise: Measures should be taken to control noise levels generated by the vibrating screen, as excessive noise can be a concern in mining operations.

Vibration: Proper balancing and isolation techniques should be employed to minimize the impact of vibrations on surrounding equipment and structures.

Compliance and Certification

Local Regulations: Ensure compliance with local regulations and industry standards specific to the region where the vibrating screens will be used.

Certifications: Look for equipment that meets relevant certifications or approvals for use in mining operations.

By adhering to these standards and considerations, vibrating screens can be optimized for performance, safety, and durability in coal mining operations. Always consult with equipment manufacturers and industry experts to ensure that the chosen equipment meets all necessary requirements.

Vibrating screens are widely used in various industries for separating materials by size, but they can encounter several common faults that can impact their performance. Here are some of the most common issues and their solutions.

Common Problems and Solutions of Vibrating Screen

1. Excessive Vibrations

Causes:

Unbalanced Screen: Imbalance in the screen due to improper loading or wear and tear of components like the vibrating motor.

Loose Bolts or Fasteners: Over time, bolts or fasteners may loosen, causing instability.

Worn Bearings: Bearings can wear out, leading to excessive vibrations.

Solutions:

Check and Balance the Screen: Ensure that the load is evenly distributed across the screen. Regularly inspect and balance the vibrating motor.

Tighten Bolts: Inspect and tighten all bolts and fasteners regularly.

Replace Bearings: If bearings are worn, replace them promptly to avoid further damage.

2. Screen Overloading

Causes:

Excessive Feed Rate: Feeding more material than the screen can handle.

Material Buildup: Accumulation of material on the screen surface, leading to reduced screening efficiency.

Solutions:

Regulate Feed Rate: Adjust the feed rate to ensure that the screen is not overloaded.

Regular Cleaning: Regularly clean the screen surface to remove any buildup and maintain efficiency.

3. Screen Blinding

Causes:

Fine Particles: Fine materials or sticky particles can clog the screen openings, preventing proper material separation.

Moisture Content: High moisture content in the material can lead to blinding.

Solutions:

Use Anti-Blinding Devices: Install anti-blinding devices like ball trays or sliders to help clear blocked openings.

Adjust Moisture Levels: Reduce the moisture content of the feed material if possible or consider pre-drying the material.

4. Screen Frame Damage

Causes:

Overloading or Impact: Excessive load or impact from large particles can cause the screen frame to crack or bend.

Fatigue: Repeated stress over time can lead to metal fatigue and eventual failure.

Solutions:

Inspect and Repair: Regularly inspect the screen frame for signs of wear and repair or replace damaged sections as needed.

Reduce Impact: Install impact protection or reduce the size of the feed material to minimize damage.

5. Inconsistent Material Flow

Causes:

Improper Installation: Incorrect installation or leveling of the vibrating screen.

Uneven Wear: Uneven wear of screen components, such as the screen mesh or frame.

Solutions:

Check Installation: Ensure the vibrating screen is installed correctly and level.

Replace Worn Components: Regularly inspect and replace worn screen mesh or other components to maintain even material flow.

6. Reduced Screening Efficiency

Causes:

Worn or Damaged Screen Mesh: Over time, the screen mesh can wear out or tear, reducing screening efficiency.

Incorrect Vibrating Parameters: Incorrect amplitude, frequency, or angle of inclination.

Solutions:

Replace Screen Mesh: Regularly inspect and replace the screen mesh if it is worn or damaged.

Adjust Vibrating Parameters: Fine-tune the vibrating parameters to optimize screening efficiency. Consult the manufacturer’s guidelines for proper settings.

7. Noise Issues

Causes:

Loose Components: Loose bolts, screen mesh, or other components can cause excessive noise.

Worn Parts: Worn bearings or other components can lead to noisy operation.

Solutions:

Tighten and Secure Components: Regularly inspect and tighten any loose parts.

Replace Worn Parts: Replace any worn bearings or other components to reduce noise levels.

8. Motor or Drive Problems

Causes:

Overheating: The motor may overheat due to overloading or lack of proper ventilation.

Electrical Issues: Wiring problems or issues with the control panel.

Solutions:

Ensure Proper Ventilation: Make sure the motor is adequately ventilated to prevent overheating.

Inspect Electrical Systems: Regularly check the wiring and control systems for any faults and repair as necessary.

Regular Maintenance Tips

Routine Inspections: Regularly inspect all components of the vibrating screen, including the screen mesh, frame, bearings, and motor.

Lubrication: Ensure that all moving parts, especially bearings, are adequately lubricated according to the manufacturer’s recommendations.

Alignment Checks: Periodically check the alignment of the motor and screen frame to ensure they are properly synchronized.

By addressing these common faults promptly and performing regular maintenance, the efficiency and longevity of vibrating screens can be significantly improved.

The vibrating screen mesh is a metal mesh structural element. Its weaving structure is usually pre-bent into a corrugated form by bending the metal wire, so that the two bends are stuck in the same position to ensure the size of the mesh. This structure makes the vibrating screen mesh have multiple forms such as bidirectional corrugated bends, locked bends, bidirectional wave separation bends, flat top bends, and unidirectional corrugated bends, and the structure is strong.

The specifications and sizes of vibrating screen mesh vary, mainly depending on the particle size characteristics and process requirements of the screened material. The following are some common vibrating screen mesh specifications and related information:

1. Comparison of sieve hole size and mesh number

The specifications of vibrating screen mesh are usually described by the mesh size and mesh number. The mesh number refers to the number of mesh holes per inch (25.4mm) in length, while the mesh size directly reflects the actual size of the mesh. The following are some common correspondences between mesh sizes and mesh numbers:

Please note that the sieve hole sizes and mesh sizes in the above table are only common specifications and are for reference only. There may be other specific specifications of sieves in actual production.

2. Screen shape and size

The vibrating screen mesh is generally square or rectangular, and its size specifications include two dimensions: length and width. Common mesh sizes include 2mm, 3mm, 5mm, 10mm, 15mm, 20mm, etc., but these dimensions usually refer to the diameter or side length of the mesh, not the overall size of the mesh. The overall size of the mesh (i.e., length and width) is determined according to the specific equipment model and production requirements.

3. Screen material and type

The material and type of the vibrating screen mesh are also important factors affecting its specifications and dimensions. Common screen materials include metal screens (such as stainless steel screens, phosphor bronze screens, etc.) and non-metallic screens (such as polymer screens, ceramic screens, etc.). In addition, there are composite screens made of two or more materials. Different types of screens have different wear resistance, tensile strength and corrosion resistance, and are suitable for different working conditions and materials.

In summary, the specifications and dimensions of the vibrating screen mesh are varied, and the specific selection should be determined according to the particle size characteristics and process requirements of the screened material. At the same time, the material and type of the screen are also important factors to consider when choosing.