Roller Screen Product Introduction
In industries such as coal mines, power plants, metallurgy, and chemical engineering, material classification and slurry separation are crucial steps in the production process. The roller screen, with its unique working principle, has become one of the core equipment in this process.
Compared with traditional vibrating screens, roller screens are less likely to encounter screen surface blockage problems when processing wet and sticky coal as well as materials with impurities. They can stably ensure the processing volume and screening effect. At the same time, their operation process has no intense vibration, low noise, and good dust-proof sealing performance. Therefore, they are increasingly widely used in scenarios such as raw coal preparation screening in coal preparation plants and inspection screening in open-pit mines.
In the technical system of the Roller Screen, there are two design schemes: one-drive multiple axes and single-drive single axis. Due to the differences in driving methods and structures, they exhibit completely different performance characteristics and applicable scenarios. A thorough analysis of these differences is of great significance for you to make precise selections and enhance production efficiency.
The Structural Differences Between The Two Types Of Roller Screens
● Single-Drive Multi-Axis Roller Screen
The single-drive multi-axis roller screen adopts a multi-axis linkage design. The entire machine consists of multiple parallelly arranged screen shafts, and all the screen shafts are linked through transmission devices (such as chains, gearboxes).
Sieve Shaft And Sieve Plate Configuration: On each sieve shaft, a parabolic roller disc is installed. The disc is made of wear-resistant manganese-chromium alloy steel and is cast as a whole. Its surface hardness reaches HRC55, which can withstand the impact and wear of materials smaller than 800mm. The service life is not less than 12,000 hours. The discs are arranged in an alternating pattern and have a larger diameter than the traditional design. This not only enhances the disturbance ability of the material flow but also reduces the entanglement of soft debris.
Mechanical Protection: The main body is made by welding Q355D low-alloy high-strength structural steel. On the side, there is a ZGMn18Cr2 wear-resistant lining plate with a thickness of no less than 25mm. This prevents the material from directly washing the box, prolonging the equipment's lifespan. Moreover, the lining plate is connected by bolts, making replacement convenient.
Sealing Design: At the connection point between the sieve shaft and the box body, an axial rubber lubrication external seal is adopted. Inside the sealing device, there are two oil channels, and lithium-based molybdenum disulfide grease is injected. This not only prevents dust from spilling out but also avoids the stone powder entering the bearing seat and damaging the bearings.
The multi-axis linkage structure design enables the materials to be subjected to the effects of the sieve shaft and the disc multiple times during the screening process, laying the foundation for efficient screening.
● Single-Drive Single-Axis Roller Screen
The structure of the single-drive single-axis roller screen is relatively simple, consisting of only one core screen shaft. The screen shaft is the sole carrier for achieving the screening function.
Core Component Configuration: The sieve shaft is also made of forged 42CrMo material. Through CAE force analysis and optimization design, it can avoid problems such as bending and fracture. The rollers and disc plates installed on the sieve shaft are mostly of the traditional type. Although they can meet the basic screening requirements, in terms of material disturbance and anti-tangling performance, they are inferior to the parabolic disc plates of the multi-axis driven roller sieve.
Protection And Sealing: The design of the body's protection and sealing largely follows industry standard practices. For instance, basic wear-resistant liners and rubber seals are installed. However, the overall protection strength and the degree of detail optimization are usually lower than those of mid-to-high-end multi-axis roller screen units.
The single-axis structure limits its screening capacity, and it can only meet the requirements of simple material classification.
The Differences In The Driving Methods Of The Two Types Of Roller Screens
● Multi-Axis Drive Mode
The multi-axis roller screen adopts the mode of "one drive unit driving multiple screen shafts". Common transmission methods include multi-axis chain drive and multi-axis linkage gearbox drive.
Drive Unit Configuration: The drive unit consists of an electric motor, a reducer, and an elastic pinion coupling. The electric motor is mostly selected as an induction type squirrel-cage motor with a protection level of no less than IP55 and F-class insulation, which can operate stably under voltage fluctuations of ±10% and frequency fluctuations of ±5%; the reducer is preferably a hard toothed type product with an efficiency of over 0.97, and the bearings use imported brands, with a service life of no less than 30,000 hours.
Transmission Advantages: Multiple axes share a single drive unit, resulting in a compact structure and high transmission efficiency. When a sieve axis experiences slight blockage, the drive unit can allocate a greater torque to the faulty sieve axis to overcome the resistance of the material, ensuring the continuous operation of the equipment; at the same time, the same drive unit drives the sieve axes synchronously, which can ensure the smooth movement of the material on the sieve surface and avoid uneven screening caused by local overload.
● Single-Motor Single-Axis Drive Mode
The single-drive single-axis roller screen adopts the mode of "one screen shaft with one set of drive device", and each screen shaft is corresponded to an independent motor and reducer.
Drive Unit Features: The configuration of the drive unit is similar to that of a single-drive multi-axis roller screen, but since each sieve shaft requires a separate drive unit, the total number of drive components in the equipment has significantly increased.
Transmission Limitations: Although independent drive can achieve overload detection for a single axis and when a single screen shaft fails, the material can rely on the inclined surface's inertia and the thrust from the previous screen shaft to continue moving past the faulty shaft, the numerous independent drive components will increase the number of potential failure points - any issue with the motor, reducer, coupling, etc., will affect the operation of the corresponding screen shaft; moreover, the simultaneous control of multiple drive systems is difficult, and it is prone to situations where the rotational speeds of the screen shafts are inconsistent, resulting in a decrease in screening accuracy.
The Performance Differences Between The Two Types Of Roller Screens
● Screening Efficiency And Accuracy
A Multi-Axis Roller Screen: Multiple axes work together, and the materials on the screen will undergo repeated disturbances and classification by multiple sets of screen axes and disc blades.
The parabolic disc blades can throw the materials forward at an angle of about 45 degrees, causing large particles to float up and small particles to sink down, thereby increasing the screen permeability;
The staggered disc blade arrangement further reduces the screening blind area, ensuring that materials smaller than the screen holes can pass through fully, resulting in higher screening accuracy. Generally, it can meet the particle size control requirements of ±1mm.
Single-Drive Single-Axis Roller Screen: It relies solely on the screening effect of a single screen shaft. The material stays on the screen for a short time and is disturbed less frequently. This often leads to situations such as "large particles mixed with small particles" or "small particles not passing through the screen".
Especially when dealing with materials with significant size differences, the screening efficiency and accuracy of this type of screen are significantly lower than those of a single-drive multi-axis roller screen.
● Processing Capacity And Stability
Processing Capacity: The multi-axis design of the one-drive multi-axis Roller Screen expands the effective screening area. The synchronous operation of the screening axes enables uniform reception of materials, avoiding local accumulation. The processing capacity is typically 30% - 50% higher than that of the same specification single-drive single-axis roller screen, and can meet the high-load requirements of large industrial production lines.
Operating Stability: The single-drive multi-axis roller screen has fewer failure points, requires less maintenance, and has a long average downtime-free operation period for the equipment.
The single-drive single-axis roller screen has more driving components, resulting in a higher failure rate. Even if a single screen shaft fails, it does not affect the overall operation, but it will lead to a decrease in local screening capacity. Over time, this can cause an uneven overall load on the equipment, shortening its service life.
● Impact Resistance
The driving unit of the multi-axis roller screen has a greater power, and the multi-axis linkage can disperse the impact load on the materials.
When dealing with large pieces of material or materials with a high content of impurities, multiple sieve shafts can jointly withstand the impact, preventing a single sieve shaft from being overloaded and damaged.
For the single-drive single-axis roller screen, the single screen shaft directly bears the impact of the materials. Over a long period of operation, it is prone to problems such as screen shaft bending and excessive wear of the disc. Its impact resistance is relatively weak.
The Application Of Two Types Of Roller Screens
● A Multi-Axis Roller Screen
Application Fields:
- Coal mines: Handling raw coal preparation screening and fine particle removal, especially suitable for wet and sticky coal, and coal with a large amount of gangue;
- Power plants: Coal classification and fuel pre-treatment, ensuring high screening accuracy to improve combustion efficiency;
- Sand and gravel aggregate industry: Separation of sludge and aggregate classification, processing materials with significant size differences (such as 0-800mm).
Scene Characteristics: Complex material properties, high screening requirements (such as a particle size deviation of ≤2mm), large processing volume (such as hundreds of tons per hour), and high requirements for the continuous operation stability of equipment.
● Single-Drive Single-Axis Roller Scree
Application Fields:
- Small-scale coal mines: Small-scale raw coal screening, with low precision requirements (such as particle size deviation ≤ 5mm);
- Chemical industry: Screening of small amounts of granular materials, with no impurities and low moisture content of the materials;
- Small-scale building materials factories: Simple screening of sand and gravel, with a small processing capacity (such as several tens of tons per hour).
Scene Characteristics: The material composition is simple, the screening requirements are low, the processing volume is small, and the enterprise can tolerate certain frequencies of equipment maintenance and downtime.
Selection And Maintenance Of Roller Screens
● Core Principles For Selection
Priority Considerations
- Material characteristics: Select one drive multi-axis based on the particle size range, humidity, and impurity content of the material - wet and sticky, high impurity content, and materials with significant particle size differences are prioritized for one drive multi-axis;
- Screening requirements: For scenarios with high precision requirements and high screening efficiency requirements, one drive multi-axis is selected;
- Processing capacity: For high-load production lines, one drive multi-axis is chosen; for low-load simple production lines, a single drive single-axis can be selected;
- Maintenance capability: When the enterprise's maintenance team is small in size and has limited technical capabilities, one drive multi-axis is prioritized as it has fewer faults and simpler maintenance.
Cost Balance
The initial purchase cost of the multi-axis driven roller screen is higher than that of the single-axis driven one, but it has lower long-term operation and maintenance costs, lower energy consumption, and higher efficiency;
The initial cost of the single-axis driven type is lower, but the later fault repair costs and energy consumption costs are higher. Enterprises need to make a comprehensive assessment based on their long-term production plans.
● Maintenance Points
A Multi-Axis Roller Screen
- Drive unit: Regularly check the motor current, grease level and temperature of the reducer to ensure that the drive unit has no abnormal vibration or noise;
- Transmission components: For chain transmission, regularly check the tension and wear of the chain; for gearbox transmission, replace the lubricating oil as required;
- Self-cleaning device: The comb-shaped cleaning device at the lower part of the sieve shaft is prone to getting stuck with soft debris. It needs to be cleaned 1-2 times per week to prevent debris from accumulating and wearing down the sieve plate;
- Lubrication system: Utilize the centralized automatic lubrication system (with the ability to set the number of oil injections and time), regularly supply oil to the bearings and transmission components. It is recommended to use M0S2 extreme pressure No. 2 lithium-based lubricating grease.
Single-Drive Single-Axis Roller Screen
- Drive components: Conduct a thorough inspection of each motor and reducer on the screen shaft, focusing on checking for loose wiring terminals and oil seal leakage;
- Screen shaft and screen plate: Due to the concentrated force on the single-axis, the inspection frequency for the bending degree of the screen shaft and the wear of the screen plate needs to be increased. Replace any problems found in a timely manner;
- Synchronization calibration: Regularly calibrate the rotational speed of each screen shaft to avoid uneven screening due to speed differences.
Common Faults Of Roller Screens And Their Solutions
Screen Plate Damage Or Blockage: For any type of roller screen, if the screen plate is broken, severely worn, or blocked, the machine should be stopped first to clean the screen surface of debris (such as iron objects, gangue), check if the screen shaft is deformed, and then replace the screen plate.
Drive Unit Abnormalities: When the motor overheats or the reducer makes abnormal noise, check if the foundation bolts are loose. If the bolts are tightened, disassemble the drive unit to check for wear on the motor winding or the reducer gears.
Stacking Problem: During equipment operation, if there is a stacking issue, stop the machine to clean, then analyze the cause - if it is caused by wet and sticky coal, adjust the screen shaft speed or increase the cleaning frequency; if it is caused by excessive coal feeding, reduce the feeding rate of the feeder; if it is caused by blockage of the screen chute, clear the chute.
With the increasing demands for screening efficiency and intelligence level in industrial production, the roller screen technology will develop towards the direction of "more efficient, more intelligent and more reliable".
In terms of the driving method, the one-drive-multiple-axis design will be further optimized - for instance, by adopting variable frequency drive technology, the rotational speed of the screening shaft can be adjusted continuously, meeting the screening requirements of different materials; at the same time, the intelligent monitoring system will be more widely applied. Through sensors, real-time data such as the temperature of the driving unit, the vibration of the screening shaft, and the screening particle size will be collected, and combined with AI algorithms, fault early warning and automatic adjustment can be achieved.
In terms of structural design, the disc and shaft of the multi-axis roller screen will evolve towards "modularization and lightweighting", such as adopting detachable discs to reduce downtime during replacement; while the single-axis Roller Screen with a single drive may be optimized towards "miniaturization and portability" to meet the needs of small enterprises and temporary screening scenarios.
No matter how technology evolves, the core differences between multi-drive multi-axis and single-drive single-axis roller screens always revolve around "efficiency, stability, and adaptability to scenarios". You only need to precisely select the model based on your production needs and perform regular maintenance to fully leverage the screening value of the roller screen and safeguard the production process.
Please feel free to contact our professional technical team. Provide us with your specific operating conditions and production capacity requirements. We will offer you free design solutions and equipment selection services, and jointly develop the most optimal technical solution!
