The working principle of vibrating screen
Vibrating screen is a kind of mechanical equipment that uses the principle of vibration to achieve material screening, and its working principle is based on the following key factors:
The motor drives the shaker to produce a specific direction and frequency of the excitation force. The shaker usually consists of an eccentric block or eccentric shaft. When the motor rotates, the unbalanced mass of the block or shaft generates a centrifugal force, which triggers the vibration.
The excitation force is transmitted to the screen box through the transmission device, causing the screen box to vibrate. The design will ensure that the vibration can be effectively transmitted and amplified on the screen surface through reasonable structure and connection.
The material placed on the screen surface is subjected to vibration, which will show a complex state of motion. Relative sliding, throwing and rolling movements will occur between the material particles and between the material and the screen surface.
Under the action of vibration, the material will be stratified according to the differences in particle size, shape and density. Smaller particles gradually fall through the sieve holes, while larger particles move along the sieve surface, and ultimately discharged from the outlet to achieve the screening of materials.
Types of vibrating screen
Structural characteristics The screen box moves in a straight line direction, usually driven by two motors of the same frequency synchronously rotating in reverse. The screen surface is usually installed horizontally or inclined.
Working Principle
The motor drives the eccentric shaft to rotate, generating the excitation force in the linear direction, so that the material moves forward in a straight line on the screen surface.
Application Scenario
It is suitable for screening materials with large particle size and high handling capacity, and is commonly used in mining, coal and other industries.
Structural characteristicsThe movement track of the screen box is circular or oval.It is usually driven by a single-shaft exciter.
Working principle
The shaker drives the screen box to do circular motion, and the material is subject to the combined effect of centrifugal force and gravity on the screen surface.
Application Scene
Widely used in quarry, building materials and other industries, the screening effect is better for medium size materials.
Structural characteristicsThe movement track is elliptical, combining the characteristics of linear vibrating screen and circular vibrating screen. Usually has a biaxial exciter.
Working principle
The combined force generated by the biaxial exciter makes the screen box do elliptical movement, and the movement of materials on the screen surface is more complex, which helps to improve the screening efficiency.
Application Scenario
It is suitable for processing materials with large viscosity and high water content, and has certain applications in chemical industry, metallurgy and other industries.
Structural characteristicsIt adopts high-frequency motor as the vibration source, and the vibration frequency is usually above 24Hz.The screen surface usually adopts stainless steel woven mesh or polyurethane screen plate.
Working principle
High-frequency vibration makes the material jumping rapidly on the screen surface, and the small particles can pass through the screen holes quickly.
Application Scenario Mainly used for accurate screening of fine-grained materials, such as tailings processing in mineral processing plants, coal depth screening, etc.
Structural characteristics
Using the resonance principle, the intrinsic frequency of the screen box and the frequency of the excitation force are close to or equal, so as to obtain a larger amplitude with a smaller excitation force.Usually has a larger processing capacity and lower energy consumption.
Working principle
When the excitation frequency is close to the resonance frequency, the amplitude of the system increases rapidly to achieve high efficiency screening.Application ScenarioApplicable to large mines and coal processing plants and other occasions that need to handle a large amount of materials.
Advantages of vibrating screen
It can quickly and accurately separate materials of different particle sizes, which greatly improves the production efficiency.Advanced design and optimised vibration parameters ensure uniform distribution and effective screening of materials on the screen surface.
With large screen surface area and reasonable structure design, it can handle a large amount of materials at the same time. Adapt to the needs of large-scale industrial production, reducing the number of equipment and floor space.
It can achieve fine grading of materials and meet the strict requirements of different industries on product particle size. The adoption of high-precision screen mesh and optimised vibration mode effectively improves the screening precision.
Composed of relatively simple parts, it is easy to manufacture, install and maintain. Fewer moving parts reduce the probability of failure and improve the reliability and stability of the equipment.
It can handle materials of various properties, including wet, sticky, abrasive and other materials with different characteristics.It can operate stably under different working environments and conditions.
Reasonable vibration design and application of energy-saving motor reduce energy consumption.Reduce the dust emission and noise pollution, in line with the requirements of environmental protection.
How to choose vibrating screen
Particle size distribution: understand the proportion of different particle sizes in the material to determine the required screening accuracy.Water content: high water content of the material may lead to clogging, you need to choose the vibrating screen with anti-blocking measures.Viscosity: viscous materials are easy to adhere to the screen surface, affecting the screening effect, should choose the screen surface with self-cleaning function. Corrosive: for corrosive materials, select the vibrating screen made of corrosion-resistant materials.
According to the production process and output requirements, calculate the required handling capacity.Select the vibrating screen model whose screen surface area and vibration parameters can meet the requirements of processing capacity.
According to the requirements of product quality, define the required screening precision.Select the vibrating screen with appropriate screen aperture and vibration frequency to ensure that the required screening precision is achieved.
Space constraints: ensure that the vibrating screen can be properly installed and operated in the installation site without affecting other equipment and operations.Temperature and humidity: extreme temperature and humidity conditions may affect the performance and life of the equipment, choose materials and protective measures to adapt to the environmental conditions.
Compare the acquisition cost of different models and brands of vibrating screens.Consider the running cost of the equipment, including energy consumption, wearing parts replacement and other maintenance costs.
Maintenance of vibrating screen
Daily inspection before starting the machine Check the integrity of the screen mesh, whether it is broken, blocked or loose.Confirm whether the fastening bolts are firm to prevent damage to parts or abnormal vibration due to loosening. Check the lubrication condition of the lubrication parts to ensure good lubrication and reduce wear and tear. Observation during operation Listen carefully to the sound of the equipment during operation, and stop the machine for inspection if there is any abnormal noise. Monitor the temperature and current of the motor to ensure that it is running within the normal range. Cleaning after work Clean up the residual materials on the screen surface to prevent the accumulation of materials from affecting the screening effect next time. Remove debris and dust around the equipment to keep the working environment tidy.
Inspection and replacement of screen mesh Regularly check the wear and tear of the screen mesh, and replace the screen mesh in time according to the degree of wear and tear. Ensure that the newly installed screen meets the screening requirements and is firmly installed. Inspection and replacement of wearing partsCheck the deformation and fatigue of the spring, and replace it in time if it is damaged.Check the aging and wear of rubber parts, and update them in time to ensure the sealing and vibration damping effect.Maintenance of transmission parts Check the tension of the belt and adjust or replace it if necessary.Check the lubrication and wear of gears, drive shafts and other transmission parts. Maintenance of electrical system Regularly check the electrical connections for firmness, looseness and oxidation.Conduct performance tests on electrical components to ensure their normal operation.
Cleaning and maintenanceBefore prolonged decommissioning, carry out a thorough cleaning of the equipment to remove dirt and residual material on the surface.Protective treatmentRustproof the parts that are prone to rust by applying anti-rust oil or covering them with a protective layer.Storage environmentStore the equipment in a dry, well-ventilated place to avoid moisture and mechanical damage.
Safety firstBefore carrying out maintenance operations, be sure to disconnect the power supply and hang a warning sign to prevent accidents caused by misuse.Follow the operating proceduresStrictly follow the maintenance manual and operating procedures of the equipment, and do not change the maintenance methods and procedures at willProfessional operationFor complex maintenance work, it should be operated by personnel with professional knowledge and skills.Record maintenanceEstablish a maintenance record file to record in detail the content, time and maintenance personnel of each maintenance, so as to trace and analyse the maintenance history of the equipment.
In summary, vibrating screen as an important screening equipment, plays an indispensable role in industrial production. An in-depth understanding of its working principle, type, advantages, and how to make the right choice and effective maintenance is of great significance for improving production efficiency, ensuring product quality, reducing production costs and extending the service life of the equipment. In practical application, vibrating screen should be reasonably selected and used according to specific production requirements and working conditions, and regular maintenance should be carried out in strict accordance with the maintenance requirements to ensure stable operation and long-term reliable service of the equipment.
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