Cold ceramic Lagging Pulley

I. Core Performance Parameters1. Ceramic LinerMaterial:95% - 99.5% Alumina Ceramic (Al₂O₃), with a Rockwell hardness of HRA 85 - 92 (second only to diamond), and its wear resistance is more than 30 times that of manganese steel.Some high-end products use Zirconia Toughened Ceramic (ZTA), with a hard...

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I. Core Performance Parameters

1. Ceramic Liner

Material:

95% - 99.5% Alumina Ceramic (Al₂O₃), with a Rockwell hardness of HRA 85 - 92 (second only to diamond), and its wear resistance is more than 30 times that of manganese steel.
Some high-end products use Zirconia Toughened Ceramic (ZTA), with a hardness up to HRA 94, and the impact resistance is increased by 30%.

Thickness:

8 - 20mm (8 - 12mm under standard working conditions, 15 - 20mm in high-wear scenarios), and it is specifically adjusted according to the particle size and speed of the conveyed materials.

Surface Treatment:

Polished treatment (surface roughness Ra ≤ 0.8μm), with a friction coefficient of 0.15 - 0.2, reducing material retention.

Pasting Process:

Cold-bonding Adhesive: Two-component epoxy structural adhesive (such as the BD series), with a shear strength ≥ 15MPa and a temperature resistance range of - 40℃ - + 400℃ (depending on the model, for example, BD300 can withstand a temperature of 300℃, and BD400 can withstand a temperature of 400℃).
Installation method: The thickness of the back coating adhesive layer is 1 - 2mm, the curing time at room temperature is 24 hours, and the initial adhesion force ≥ 5N/cm (no support is required when pasting on a vertical surface).

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I. Preparation before Installation

Foundation Inspection

Confirm that the levelness error of the installation bracket is ≤ 2mm/m, and the perpendicularity error between the axis of the drum and the center line of the conveyor belt is ≤ 1°.
The spacing of the anchor bolt holes should match the drum flange to avoid deformation caused by forced assembly.

Coupling Alignment

The radial deviation of the elastic coupling is ≤ 0.15mm, and the deviation of the end face clearance is ≤ 0.5mm (refer to the equipment manual).
Use a laser alignment instrument or a dial indicator for calibration to avoid vibration or bearing damage caused by misalignment.

II. Installation Process

Drum Positioning

Use special lifting tools to hoist the drum steadily, and it is prohibited to collide with the rubber surface or the bearing part.
After leveling, pre-tighten the anchor bolts first, and finally tighten them after the coupling is aligned (the torque value should be in accordance with the design requirements).

Tensioning and Belt Adjustment

The counterweights on both sides of the tensioning device need to be released synchronously to avoid unilateral stress on the conveyor belt.
The tension of the conveyor belt should meet the design value (usually 1/10 to 1/8 of the breaking force of the conveyor belt). Excessive tension will accelerate wear, and too loose tension will lead to slipping.

Protection and Sealing

Keep a gap of 5-10mm between the protective cover and the drum to prevent friction.
Check the sealing parts of the bearing end cover to avoid dust entering; for oil-cooled drums, ensure that there is no oil leakage in the oil circuit.

III. Debugging Key Points

No-load Test Run

The idling time is ≥ 30 minutes, and monitor the temperature rise of the bearing (≤ 35°C) and the vibration value (≤ 1.5mm/s).
Observe the deviation of the conveyor belt, and correct it by fine-tuning the position of the drum (the lateral movement is ≤ 2mm) or the tensioning device.

Load Test

Gradually load to the rated load, and check whether the friction force between the drum and the conveyor belt is sufficient (when slipping occurs, increase the roughness of the rubber surface or adjust the wrap angle).
Check whether the coupling bolts and anchor bolts are loose, and tighten them in time.

IV. Precautions for Special Environments

Explosion-proof Area

Use copper tools or explosion-proof electric tools to avoid the generation of sparks.
Detect the gas concentration in the environment before installation (< 0.5%), and live working is prohibited.

Low-temperature Environment

Preheat the drum to above 5°C before starting to prevent the rubber surface from embrittlement and cracking.
Select cold-resistant rubber (such as nitrile rubber) to avoid slipping caused by hardening at low temperatures.

V. Safe Operation

Power-off and Lockout

Strictly implement the power-off and power-on system. Lock the control switch and hang a warning sign, and the key should be kept by a designated person.
Confirm that all personnel have evacuated the dangerous area before the test run, and it is prohibited to touch the rotating parts with hands or tools.

Lubrication and Inspection

Add lubricating grease to the bearing according to the regulations (the filling amount is 1/3 to 1/2 of the bearing chamber), and fill the oil level of the oil-cooled drum to the oil level line.
Listen to the sound of the bearing during operation, and stop the machine immediately to check if there is abnormal noise.

Reminder: After the installation is completed, fill in the "Equipment Maintenance Record", record the debugging data (such as tension force, temperature rise), and file it for future reference. During regular maintenance, focus on checking the contact state between the drum and the conveyor belt and the change of the bearing clearance.

How to select the diameter of the driving drum?

How to Select the Diameter of the Driving Drum?

The selection of the diameter of the driving drum needs to comprehensively consider the following technical factors:

Conveyor Belt Tension and Torque Requirements

The diameter should meet the requirements of torque transmission (Torque = Tension × Radius) to avoid the slipping of the conveyor belt.
Calculation formula: $D = \frac{2 T}{F}$ , where $T$ is the driving torque and $F$ is the tension of the conveyor belt.

Number of Layers of the Conveyor Belt and Bending Stress

An excessively small diameter will cause the conveyor belt to bend excessively, reducing its service life.
Empirical formula: $D \geq (125 \sim 150) \times δ$ ( $δ$ is the total thickness of the conveyor belt, in mm).

Drum Material and Allowable Stress

The diameter of a steel drum is usually between 200mm and 1200mm. Cast iron drums require a larger diameter to reduce stress.
The strength needs to be verified through finite element analysis.

Driving Power and Wrap Angle

A high-power system requires a larger diameter to increase the friction force (Friction force ∝ Diameter × Wrap Angle).
Recommended range of the wrap angle: 180° to 240°, and it can reach 300° under special working conditions.

Industry Standards and Application Scenarios

For general belt conveyors: The diameter is often between 500mm and 800mm (refer to GB/T 987-2017).
For explosion-proof equipment in underground mines: A lightweight design should be selected, and the diameter is usually ≤ 630mm.

How to Select the Diameter of the Driving Drum Based on Conveyor Speed？

The diameter of the driving drum must be chosen by balancing conveyor belt bending stress, rotational speed compatibility, and system efficiency. Below is a detailed method:

1. Relationship Between Speed and Bending Stress

Bending Frequency: Higher speeds increase the frequency of belt bending over the drum, necessitating a larger diameter to reduce fatigue
.Empirical Formula: $(D geq (125 sim 150) imes delta quad (delta = ext{total belt thickness, mm}))$ Use the upper limit for high-speed conveyors ( $(v > 4 , ext{m/s})$ ).
Speed Compatibility: The drum rotational speed $n$ relates to belt speed $v$ as: $(n = rac{60v}{pi D} quad ( ext{rpm}))$ Ensure $n$ aligns with the reducer output speed (typically $(n leq 300 , ext{rpm})$ ).

2. Industry Standards and Application Scenarios

General Belt Conveyors (GB/T 987-2017):

Low speed ( $(v leq 2 , ext{m/s})$ ): 500–630 mm.
Medium–high speed ( $(2 , ext{m/s} < v leq 4 , ext{m/s})$ ): 630–800 mm.
High speed ( $(v > 4 , ext{m/s})$ ): Custom large diameters (≥ 1000 mm) or multi-drum drives.

Special Conditions:

Underground explosion-proof equipment: Diameter ≤ 630 mm (space-limited; compensate with increased wrap angle or optimized rubber surfaces).
High-angle conveyors: Larger diameters to enhance friction and prevent slippage.

3. Torque and Power Verification

Torque Formula: $(T = F imes rac{D}{2} quad ( ext{driving torque}))$ $(F = ext{belt tension})$ ; ensure torque stays within reducer/motor ratings.
Power Compatibility: $(P = rac{F imes v}{1000} quad ( ext{kW}))$ High-speed systems require larger diameters to reduce torque and avoid reducer overload.

4. Comprehensive Selection Steps

Determine belt speed $v$ and belt parameters ( $(delta)$ , allowable tension).
Initial diameter: Calculate $(D_{ ext{min}} = (125 sim 150)delta)$ .
Verify speed: Ensure $(n = 60v/(pi D))$ matches the reducer output.
Calculate torque/power: Validate against system capacity.
Adjust diameter: Choose the closest standard size (e.g., 500, 630, 800 mm) that meets requirements.

5. Example

Conditions: $(v = 3 , ext{m/s})$ , $(delta = 8 , ext{mm})$ .
Calculation: $(D_{ ext{min}} = 150 imes 8 = 1200 , ext{mm})$ Use 1000 mm (standard size) and compensate with increased wrap angle or rubber surface.

6. Precautions

Avoid undersizing: Small diameters cause premature belt failure or reducer overload.
Cost balance: Larger diameters increase costs; balance between service life and economy.
Dynamic testing: Validate vibration and temperature rise in high-speed systems during no-load trials.

By following these steps, the driving drum diameter can be optimized for conveyor speed, ensuring efficient and stable system operation.

Differences Between Slag Discharge Drums and Common Drums？

Slag discharge drums and common drums differ significantly in design, function, and application scenarios. The details are as follows:

1. Structural Design

Slag Discharge Drums:
Typically feature specialized structures such as grooves, inclined surfaces, long holes, or double-cone designs. Some models use hollow cylinders (e.g., "basket drums") to facilitate material discharge and cleaning. The surface may be rubber-coated or cast for enhanced wear resistance and anti-slip properties.
Common Drums:
Have a simpler structure, usually with smooth or rubber-coated surfaces. They consist mainly of a cylinder, hub, and bearings, without dedicated slag discharge mechanisms.

2. Core Functions

Slag Discharge Drums:
Primarily designed for efficient slag removal and solid waste separation. Their specialized structures minimize material buildup, prevent blockages, and reduce belt damage in systems handling slag-laden or sticky materials.
Common Drums:
Serve general purposes like transmitting traction (e.g., drive drums) or changing belt direction (e.g., redirect drums). They lack slag discharge capabilities.

3. Application Scenarios

Slag Discharge Drums:
Widely used in industries such as coal, power, chemicals, steel, and ports for conveying systems with high slag, ore, or sticky material content. For example, "basket drums" in aluminum ore production lines address material accumulation issues.
Common Drums:
Applied in general conveyor systems across logistics, mining, and metallurgy, suitable for clean or conventional material transportation.

4. Performance Characteristics

Slag Discharge Drums:

Material: Constructed from wear-resistant steel (e.g., manganese steel) for durability.
Belt Protection: Reduce belt slippage and Deviation risks, lowering maintenance costs.
Stability: Some models feature higher middle and lower sides to improve stability and friction.

Common Drums:

Load Capacity: Prioritize load-bearing and transmission efficiency, categorized as light, medium, or heavy-duty.
Surface Treatment: Rubber coating enhances anti-slip properties but lacks slag discharge functionality.

Summary

Slag discharge drums are specialized equipment tailored for complex environments (e.g., high-impurity, high-clogging conditions), while common drums are better suited for standard conveying needs. Selection depends on material properties, operational environment, and maintenance requirements.

How to Determine the Rotation Direction of a Slag Discharge Drum

The rotation direction of a slag discharge drum is critical for efficient slag removal and preventing material buildup. Here's how to determine it:

1. Follow the Structural Design

Grooves/Inclined Surfaces:
If the drum has grooves or inclined surfaces, the rotation direction should align with the slope to guide slag outward. For example, a drum with helical grooves should rotate in the direction that pushes slag toward the discharge outlet.
Hollow/Basket Drums:
Hollow drums (e.g., "basket drums") often require rotation that centrifugally flings slag through the openings. Test both directions to see which minimizes material retention.

2. Match Material Flow Direction

Downstream Conveyor:
Ensure the drum rotates in the same direction as the primary conveyor belt to maintain continuous slag discharge. Reverse rotation might cause backflow or blockages.
Gravity-Assisted Discharge:
If the drum is positioned above a chute or hopper, rotate it to direct slag downward (e.g., clockwise if the discharge point is on the right side).

3. Consider Equipment Layout

Belt Tensioning:
The rotation direction may depend on how the drum interacts with tensioning devices (e.g., idlers or pulleys). Ensure it aligns with the belt’s tensioning force to prevent slippage.
Space Constraints:
If the drum is near walls or other machinery, rotate it to avoid projecting slag into restricted areas.

4. Test and Adjust

Initial 试运行:
Start with a low-speed test run. Observe slag discharge patterns—if material accumulates on one side, reverse the direction.
Monitor Belt Wear:
Incorrect rotation may cause uneven belt wear. Adjust direction if excessive friction occurs.

5. Manufacturer Guidelines

Always refer to the drum’s technical documentation for recommended rotation direction, especially for specialized models (e.g., double-cone drums).

Example: Basket Drum Rotation

A basket drum in an aluminum ore conveyor should rotate clockwise if:

The discharge chute is positioned on the drum’s right side.
The design uses centrifugal force to expel ore through the basket’s holes.

Reverse rotation (counterclockwise) might trap material inside the basket.

Key Takeaways

Structure first: Align rotation with grooves, slopes, or hollow openings.
Flow consistency: Match the conveyor’s direction and gravity flow.
Trial and error: Test directions to optimize slag removal and minimize maintenance.

By combining these factors, you can ensure the drum operates efficiently and prevents costly blockages.

Causes and Solutions for Excessive Noise in Slag Discharge Drums？

Excessive noise in slag discharge drums often stems from mechanical wear, operational inefficiencies, or design flaws. Below is a structured analysis of common causes and practical solutions:

1. Mechanical Wear and Tear

Causes:

Worn bearings (e.g., due to dust ingress or lack of lubrication).
Damaged or misaligned rollers/bushings.
Surface abrasion from high-impact materials (e.g., ores, slag).

Solutions:

Replace bearings with sealed, dust-resistant models (e.g., spherical roller bearings).
Inspect and realign rollers to ensure smooth rotation.
Apply wear-resistant coatings (e.g., ceramic or polyurethane) to the drum surface.

2. Dynamic Imbalance

Causes:

Uneven slag accumulation on the drum surface.
Manufacturing defects leading to mass distribution irregularities.

Solutions:

Perform dynamic balancing tests to identify and correct imbalances.
Regularly clean the drum to prevent slag buildup.
Use weighted counterweights if imbalance persists.

3. Misalignment or Loose Components

Causes:

Improper alignment between the drum and conveyor belt.
Loose fasteners or structural supports.

Solutions:

Adjust the drum’s position using alignment tools (e.g., laser alignment kits).
Tighten bolts and reinforce brackets with vibration-damping materials (e.g., rubber pads).

4. Lubrication Issues

Causes:

Inadequate or deteriorated lubrication leading to friction.
Incorrect grease type for high-temperature or corrosive environments.

Solutions:

Use high-temperature grease (e.g., lithium-based) for extreme conditions.
Implement a scheduled lubrication plan with automatic grease injectors.
Clean old grease and debris before reapplying fresh lubricant.

5. Material-Related Issues

Causes:

Blockages in the drum’s discharge openings (e.g., by sticky slag).
High-velocity impact of materials against the drum surface.

Solutions:

Optimize the drum’s design (e.g., larger discharge holes, helical grooves) to reduce blockages.
Install impact-resistant liners (e.g., rubber or manganese steel) to absorb material 冲击.
Adjust conveyor speed to minimize sudden material surges.

6. Design and Installation Flaws

Causes:

Inadequate rigidity of the drum structure.
Incorrect mounting angles leading to excessive vibration.

Solutions:

Reinforce the drum’s frame with additional supports.
Install anti-vibration mounts (e.g., spring-dampened bases) to isolate noise.
Adjust the drum’s inclination angle to align with material flow.

7. Environmental Factors

Causes:

High ambient temperatures causing thermal expansion.
Dust and moisture ingress into moving parts.

Solutions:

Use heat-resistant seals and coatings for high-temperature applications.
Enclose the drum in a dust-proof housing with airtight gaskets.

Example: Basket Drum Noise Reduction

If a basket drum in a steel plant produces loud noise:

Check for blockages in the basket’s holes and clear debris.
Replace worn bearings with corrosion-resistant models.
Add rubber liners to the basket interior to dampen material impact.

Key Preventive Measures

Regular Maintenance: Inspect bearings, alignment, and lubrication weekly.
Material Monitoring: Adjust conveyor speed to match the drum’s capacity.
Noise Insulation: Install acoustic enclosures or sound-absorbing panels around the drum.

By addressing these root causes, you can reduce noise levels, extend equipment lifespan, and improve operational safety.

The Role of Built-in Bearing Drums？

A built-in bearing drum (also known as an "integral bearing drum") is a specialized component used in industrial machinery, particularly in applications like conveyor systems, crushers, and slag discharge equipment. Its primary purpose is to integrate the bearing function directly into the drum’s structure, offering advantages over traditional externally mounted bearings. Below is a detailed breakdown of its role:

1. Structural Integration and Space Efficiency

Compact Design:
Built-in bearings eliminate the need for separate external bearing housings, reducing overall size and complexity. This is especially beneficial in confined spaces or mobile equipment.
Simplified Installation:
The drum and bearings are pre-assembled as a single unit, streamlining installation and alignment compared to modular designs.

2. Reduced Friction and Wear

Optimized Rotation:
Bearings integrated into the drum’s core ensure smooth, low-friction rotation, minimizing energy consumption and mechanical wear.
Sealed Protection:
Built-in bearings are often enclosed within the drum’s structure, protecting them from dust, moisture, and corrosive materials (e.g., slag, chemicals). This extends bearing lifespan and reduces maintenance needs.

3. Enhanced Load Distribution

Uniform Support:
Bearings positioned inside the drum distribute loads evenly across the entire length of the rotating shaft, preventing sagging or misalignment in heavy-duty applications (e.g., conveying ores or waste).
Stability:
The integrated design improves the drum’s dynamic balance, reducing vibration and noise during operation.

4. Adaptation to Harsh Environments

High-Temperature Resistance:
In systems exposed to extreme heat (e.g., steel mills, incinerators), built-in bearings can be designed with heat-resistant materials (e.g., ceramic or specialized alloys) to maintain performance.
Corrosion Resistance:
Sealed, internal bearings avoid direct contact with corrosive substances, making them suitable for industries like chemical processing or wastewater treatment.

5. Specialized Applications

Slag Discharge Systems:
Built-in bearings in slag drums help withstand abrasive materials and high impact forces while ensuring continuous, efficient rotation for slag removal.
Waste Management:
In shredders or composting equipment, these drums handle heavy loads and organic debris without frequent maintenance.

6. Maintenance Advantages

Longer Service Intervals:
Protected bearings require less frequent lubrication and replacement compared to externally mounted ones.
Modular Replacement:
If a bearing fails, the entire drum unit can be swapped out quickly, minimizing downtime.

Example: Built-in Bearings in Slag Discharge Drums

In a steel mill’s slag conveyor:

Problem: Externally mounted bearings often fail due to slag dust ingress and high temperatures.
Solution: A built-in bearing drum with sealed, heat-resistant bearings reduces failures by 70%, requiring maintenance only every 6 months instead of monthly.

Key Takeaways

Integration: Combines bearing and drum functions for compactness and stability.
Durability: Protects bearings from harsh conditions, extending equipment life.
Efficiency: Reduces friction, energy use, and downtime.

By leveraging built-in bearings, industries can optimize performance in challenging environments while lowering operational costs.