How to effectively solve the problems of feeder deviation, material spillage or resonance during operation

The production efficiency of mines and mineral processing plants relies heavily on the stable operation of mineral ore feeding equipments. As the critical first step in material transportation and control, feeder failures such as tracking deviation, material spillage, or resonance can directly lead to reduced production capacity, increased material loss, increased equipment wear, and even safety hazards. This article will provide a thorough analysis of the causes of these three major failures from a professional technical perspective and provide practical solutions based on engineering experience.

Belt Feeder Tracking Problems and Professional Correction

Tracking is the most common belt feeder failure. Essentially, it occurs when the longitudinal centerline of the conveyor belt and the centerline of the equipment are not aligned.

1. Root Cause Analysis of Tracking:

Installation Accuracy Error: Geometric errors in the installation of components such as the frame, rollers, and drums, particularly when the axes of the drive and return drums are not perpendicular to the frame centerline.

Material Overload: Improper placement of the ore drop point or a poorly sealed chute can lead to material accumulation on one side, resulting in uneven belt tension on both sides.

Belt Quality Issues: Uneven belt thickness or strength can cause unbalanced force during operation.

Roller Adhesion or Damage: Ore dust adheres to the roller surface or the roller becomes damaged and stuck, increasing belt resistance on one side.

2. Professional Corrective Measures and Engineering Practices:

Roller Adjustment: If the belt consistently runs to one side on the roller, the roller should be precisely adjusted. For example, if the belt runs to the left of the roller, the left bearing seat should be moved forward in the direction of belt travel (or the right side should be moved backward). Adjustments should be small and repeated, typically by adjusting a screw or shims.

Self-Aligning Roller Applications: Self-aligning rollers are installed in the return section of the belt conveyor or in sections prone to deviation. These rollers automatically correct belt deviation through tilting or friction, but should not be used as the primary correction method; they should only be used as an auxiliary tool.

Tensioning Device Optimization: Ensure even force on both sides of the take-up device and regularly check that the tension is within the designed range. Excessive or insufficient tension can cause deviation.

Drop Point Optimization: Redesign or adjust the chute and skirt to ensure that the ore lands centrally on the belt, distributing it evenly and eliminating uneven loading.

Material Spillage Control and Sealing Technology

Material Spillage refers to ore spilling from the sides or tail of the feeder during conveying, causing environmental pollution and material loss.

1. Main Areas and Causes of Material Spillage:

Head End Spillage: Mainly occurs at the drum discharge point and is related to chute design and belt speed.

Tail End Spillage: Typically occurs where the belt enters the chute and is caused by material impact, poor chute design, or skirt seal failure.

Material spillage on both sides of the skirt: This may be caused by excessive clearance between the skirt and the belt, skirt wear, or aging and failure of the sealing material.

2. Professional material spillage control strategies:

Multi-layer non-contact sealing skirts: Use segmented, double-layer, or triple-layer sealing skirts (skirting rubber). The inner layer, made of wear-resistant polyurethane or rubber, adheres tightly to the belt to block fine material; the outer layer, made of flexible material, forms a secondary line of defense. The key is to maintain appropriate gap pressure to achieve both sealing and reduced belt wear.

Impact bed application: In the impact zone of the conveyor belt, a high-molecular-weight polyethylene impact bed replaces traditional impact rollers. The impact bed fully absorbs the impact of the material, ensuring uniform and stable force on the belt, effectively preventing spillage caused by sudden belt sag.

Optimizing the chute design: Ensure the chute is long enough to allow the material to settle, and its slope should be adapted to the material's natural angle of repose. Deflector plates should be installed at the outlet to ensure a smooth transition.

Weighted tensioner: Ensures sufficient belt tension in the impact zone of falling material to prevent belt vibration or edge sagging under impact.

Resonance and vibration reduction design for vibrating feeders

Resonance is a serious fault unique to vibrating feeders. It occurs when the excitation frequency approaches the natural frequency of the feeder system, resulting in a sharp increase in amplitude, potentially causing structural damage and foundation cracking.

1. Resonance mechanism and hazards:

Natural frequency drift: The natural frequency of the equipment is affected by factors such as material weight, spring stiffness changes, and foundation settlement. Resonance occurs when the natural frequency drifts due to various reasons (such as a loose exciter, spring damage, or material sticking to the machine body) and approaches the operating frequency.

Hazards: Uncontrolled amplitude, increased noise, accelerated fatigue of the exciter bearings and gears, and fracture of the frame structure.

2. Professional Anti-Resonance and Vibration Reduction Solutions:

Frequency Modulation and Vibration Isolation Design:

Avoiding Resonance Zones: During the design phase, the feeder's operating frequency (e.g., the motor speed corresponding to a 50Hz or 60Hz grid frequency) must be offset from the equipment's natural frequency. The ratio of the natural frequency to the operating frequency should generally be kept away from 1.0, for example, around 0.7 or 1.3.

Rubber Vibration Isolators: Using rubber springs or air springs as vibration isolation elements, they offer a higher damping ratio than steel springs and can effectively absorb vibration energy, reducing peak amplitude during resonance.

Vibrator and Counterweight Adjustment:

Regularly check the vibrator's eccentric counterweight for looseness or displacement.

For dual-mass or inertial vibrating feeders, precisely adjust the counterweight to ensure balanced excitation torque on both sides and eliminate unnecessary lateral vibration.

Foundation and Installation: Ensure the feeder is installed on a sturdy, level, and high-quality foundation. Insufficient foundation stiffness or uneven settlement can also change the natural frequency of the system and induce resonance.