Linear Vibrating Screen

The linear vibrating screen uses vibration motor excitation as the source of vibration power, so that the material is thrown up on the screen while moving forward in a straight line. The material enters the inlet of the screening machine evenly from the feeder, and generates data through the multi-layer screen. The oversieve and undersieve of various specifications are respectively discharged from their respective outlets. It has low energy consumption, high output, simple structure, easy maintenance, fully enclosed structure, no dust spillage, automatic discharge, and is more suitable for assembly line operations. The linear vibrating screen can also screen and classify powder and granular materials, and is widely used in plastics, abrasives, chemicals, medicine, building materials, food, carbon, fertilizers and other industries.

 

The linear vibrating screen is driven by dual vibration exciters. When the two vibration exciters are synchronized and rotated in opposite directions, the excitation force generated by the eccentric block cancels each other in the direction parallel to the motor axis, and in the direction perpendicular to the motor axis. Stacking is a resultant force, so the trajectory of the screen machine is a straight line. The two motor shafts have an inclination angle relative to the screen surface. Under the combined force of the exciting force and the material's self-gravity, the materials are thrown up and jump forward on the screen surface for linear motion, so as to achieve the purpose of screening and grading the materials. It can be used to realize automated operations in the assembly line. It has the characteristics of low energy consumption, high efficiency, simple structure, easy maintenance, and a fully enclosed structure without dust spillage. The maximum sieving mesh is 400 meshes, which can screen out 7 kinds of materials with different particle sizes.

Structural parts
It is mainly composed of screen box, screen frame, screen mesh, vibration motor, motor base, vibration damping spring, bracket, etc.
1. Screen box: It is welded by several steel plates with different thicknesses. It has certain strength and rigidity and is the main part of the screen machine.
2. Screen frame: It is made of pine wood or wood with small deformation, which is mainly used to keep the screen flat and achieve normal screening.
3. Screen: There are several kinds of screens such as low-carbon steel, brass, bronze, and stainless steel wire.
4. Vibration motor: (For details of usage and maintenance methods, please refer to the instruction manual of the vibration motor).
5. Motor pedestal: To install the vibration motor, the connecting screws must be tightened before use, especially three days before the trial of the new screen, it must be tightened repeatedly to avoid loosening and causing accidents.
6. Vibration damping spring: prevent vibration from being transmitted to the ground, while supporting the full weight of the screen box. The spring must be perpendicular to the ground during installation.
7. Bracket: It is composed of four pillars and two channel steels to support the screen box. The pillars must be perpendicular to the ground during installation, and the channel steels under the two pillars should be parallel to each other.

Influencing factors
1. Material properties
(1) Material loose density
Block materials with larger loose density are easy to penetrate through the sieve, and the screening efficiency is also higher; on the contrary, materials with lower loose density and powdery materials are not easy to penetrate through the sieve, and the screening efficiency is also low. The loose density of asphalt mixture is generally about 1.6t/m3.
(2) Material particle composition
In order to improve the screening efficiency, it is necessary to determine the sieve size of the vibrating screen when the gradation composition of the material to be screened is determined, so that the difficult-to-screen materials (materials with a particle size of 0.7 to 1 times the sieve size) account for the material under the screen. The proportion is the smallest.
(3) The relative size of material particle size and sieve hole
The particle size of the mineral material should be strictly controlled within the technical parameters of the equipment. If the particle size index difference is too large, it will cause a large production cycle and restrict the quality and processing capacity of the product. The penetration probability of materials in the screening process is affected by many factors, among which the most self-contained and important factor is the relative size of the particle size of the material and the size of the sieve hole.
2. Screen surface structure parameters
(1) Length and width of screen surface
Generally speaking, the width of the screen surface directly affects the productivity, and the length of the screen surface directly affects the screening efficiency. The screen surface is long, the material stays on the screen surface for a long time, and there are many opportunities to penetrate the screen, so the screening efficiency is high. In fact, the width of the screen surface has different effects on the screening efficiency and the length of the screen surface has different effects on the screening capacity. Generally, the ratio of width to length is 1:2~1:3.
(2) Screen shape and size
The choice of sieve hole shape mainly depends on the requirements for the particle size of the sieved product and the use of the lower product. Compared with other shapes of sieve holes, if the nominal size is the same, the thickness of the sieve through the round sieve is smaller.
(3) vibration characteristic parameters of the vibrating screen
(1) The inclination angle of the screen surface α
The angle between the screen surface and the horizontal plane is called the screen surface inclination angle. The size of the inclination angle is closely related to the processing capacity of the screening equipment and the screening efficiency. When the inclination angle increases, the throwing strength of the material on the screen will increase, so that the forward movement speed of the material on the screen surface will increase, so that the processing capacity of the screen machine will increase, but the residence time of the material on the screen surface will be shortened, reducing the chance of particle penetration. Reduce the screening efficiency. On the contrary, the processing capacity will be reduced, thereby increasing the screening efficiency. For example, Yantai Xinhai linear vibrating screen has an adjustable screen surface inclination, which greatly improves the screening efficiency and is widely used.
(2) Vibration direction angle δ
The angle between the vibration direction line and the upper screen surface is called the vibration direction angle. The greater the value of the vibration direction angle, the shorter the distance the material moves during each throwing motion, the slower the forward movement speed of the material on the screen surface, the material can be fully screened, and thus a greater screening efficiency can be obtained.
(3) Amplitude A and frequency ω
As the amplitude increases, the clogging of the sieve holes will be greatly reduced, and it is also conducive to the stratification of materials. The increase of the vibration frequency can increase the number of bounces of the material on the screen surface, and increase the probability of the material through the screen, which is very helpful for accelerating the screening speed of the material and improving the screening efficiency. The choice of amplitude is based on the particle size and properties of the material being screened. For materials with larger particle size, choose larger amplitude and lower frequency; for materials with finer particle size, choose smaller amplitude and higher frequency.
4. Selection of vibration motor and adjustment of excitation force
(1) Selection of vibration motor
As the vibration source of the vibrating screen, the vibrating motor should have the advantages of reasonable design, simple structure, compactness, high vibration excitation efficiency, energy saving, and convenient installation and debugging. The selection of the vibration motor should specifically select the expensive operating frequency, maximum excitation force, power, etc. The speed of the vibration motor should be close to the operating frequency; the maximum exciting force must be within the range of the selected motor's synthetic exciting force; then the power of the vibration motor should be selected according to the selected operating frequency and maximum exciting force.
(2) Adjustment of exciting force
Exciting force is the main factor that affects the productivity of vibrating screen. Productivity has an exponential relationship with the exciting force. The increase in exciting force causes a rapid increase in productivity, while the blocking rate decreases rapidly with the increase in exciting force. The increase of the excitation force increases the vibration intensity. The force on the screen surface to the material increases, and the upward movement speed of the material increases. The productivity is improved, and the blockage rate is reduced.
The exciting force of the vibrating motor is the centrifugal inertial force generated by the high-speed rotating eccentric mass. Change the eccentricity, thereby changing the amplitude of the exciting force, in order to achieve the effect of adjusting the exciting force. By adjusting the magnitude of the exciting force, the highest productivity is achieved and the service life of the exciting motor is prolonged.

Use operation
After the test run is over, check that the above content is correct, re-tighten all the fasteners, the screen and all parts are well fastened, and then it can be used officially. Prior to this, the following work must be done:
1) Training of operators
You should understand the structure and simple working principle of each part of the equipment; before work, you should prepare for driving, check that the rotating parts are flexible and free of jams, the screen is intact, the parts are not loose, and the bolts are fastened.
2) Start and stop without load
Vibrating screens are generally used in crushing and screening complete sets of equipment or washing processes, and the screens are required to start and stop without load. Therefore, it is necessary to follow the principle of reverse process start and shutdown along the process. Except for special reasons, parking with materials is not allowed. When there is accumulated material on the screen surface, it must be removed before starting. Feeding can only be started after normal operation.

Use classification
ZKB type use
It is widely used in coal preparation, ore dressing, building materials, electric power and other industries. It is suitable for dry and wet classification of medium and fine-grained materials or occasions such as dehydration and de-intermediation and de-sliming.
Adopting block eccentric self-synchronizing vibration exciter; Adopting elastic coupling and universal coupling connection with tape; Applying modern technology such as modal analysis to ensure the dynamic performance of the machine, and optimize the structural design to improve the reliability and working life of the whole machine.
FS type use
FS direct vibrating fine powder screen is a multi-layer powder vibrating screen, which is mainly used to screen powdered materials such as abrasives, chemical raw materials, metallurgical materials, building materials, etc. The graded particle size can be up to 200 meshes or less.
Model description: 3FS-XX XX 3 (number of layers) F (fine powder) S (vibrating screen) XX (screen surface width (dm))) XX (screen surface length (dm))

Motor instructions:
This series of motors can continuously output rated excitation force when they meet the following conditions.
1.Vibration acceleration: no more than 7g (g: acceleration due to gravity)
2.Ambient temperature: no more than 40ºC
3.Altitude: not more than 1000m
4.Power frequency: 50Hz
5.Voltage: 380V
6.Temperature rise: less than 80K (resistance method)

Installation and maintenance
Preparation before installation
1. Check whether the motor label meets the requirements.
2. Check whether the surface of the motor is damaged or deformed.
3. Check the fasteners of the motor to prevent loosening.
4. Check the power supply to see if it lacks phase, and run it for 5 minutes without load.
5. Check whether the rotation is flexible, if there is any abnormality, it should be eliminated.
6. Measure the insulation resistance with a 500 volt megger. The value should be dried on the stator winding, and the drying temperature should not exceed 120°C.

Installation and adjustment
1. The motor should be fastened on the mounting surface, and the mounting surface must be smooth and flat.
2. The motor can be installed horizontally.
3. Adjustment of exciting force.
4. The motor should be grounded reliably. There is a grounding device in the motor, and the lead end has a mark. It can also be grounded with a solid bolt on the foot.
5. The motor lead adopts four-core rubber cable YZ-500V. When connecting to the power supply, the lead-out cable is not allowed to be snapped, and it is reliably fixed to the vibrating body

Use and maintenance
1. The machine should be equipped with electrical protection devices.
2. In the early stage of operation of the machine, check the anchor bolts at least once a day to prevent loosening.
3. When the rotation direction of the motor does not meet the requirements, just adjust the phase sequence of the power supply.
4. When the machine is used again after being parked for a long time, the insulation resistance should be measured. It should be greater than 0.5 megohm for 500V megohmmeter measurement.
5. After the machine has been running for 1500 hours, the bearings should be checked, and if there is serious damage, they should be replaced immediately.
6. The motor should be well lubricated. Lithium-based grease (ZL-3) should be replenished every two weeks or so. When refueling, add an appropriate amount of lithium-based grease through the oil cup. When using sealed bearings, the motor is not equipped with an oil cup.

Daily maintenance
1. Before starting:
(1) check whether the coarse and fine meshes are damaged
(2) check whether the transportation support is removed
2. When starting:
(1), pay attention to whether there is abnormal noise
(2), whether the current is stable
(3), whether the vibration is abnormal
3. After use: clean up after each use
Regular maintenance
Regularly check the coarse mesh, fine mesh and spring for fatigue and damage, and whether various parts of the fuselage are damaged due to vibration. The parts that need to be lubricated must be lubricated.

Installation and commissioning and commissioning
(1) Installation:
1.Before installing the machine, first check whether the parts are complete and damaged according to the packing list.
2.Install the equipment according to the installation drawing. The foundation should have sufficient rigidity and strength to support all the dynamic and static loads of the vibrating screen.
3.Ensure that a minimum gap of 75mm should be maintained between the screen box and non-moving parts such as hoppers and chutes.
4.When installing, the four corners of the screen box should be level.
(2) Adjustment and trial operation:
1.The spring must be in a vertical state, and the contact surface between the upper spring support and the spring must be horizontal. After adjustment, the upper spring support is fixed on the trunnion of the screen box with bolts, and then welded into a whole.
2.The no-load test run time is not less than 2 hours. After the no-load test run is qualified, it can be put into the load test run, and the load test run can be carried out according to the process test run requirements
 

Instructions for use
Features
1. The design of the sieve machine is exquisite and easy to assemble, and one person can operate the sieve machine.
2. Compared with other related brand manufacturers, it has a larger screening area and high-efficiency processing capacity. .
3. Unique screen structure design, convenient and quick to replace the screen (only 3 to 5 minutes), in addition, this design allows the use of various screens (nylon, special dragon, PP mesh).
4. The mother mesh completely supports the fine mesh, so the fine mesh can have a longer lifespan, while reducing the use of fine mesh consumables, and the long-term production process can reduce many costs.
effect
The basic principle is to use the weights (uneven weights) installed at the upper and lower ends of the motor shaft to convert the rotation of the motor into a horizontal, vertical, and inclined three-dimensional motion, and then transmit this motion to the screen surface. If the phase angle of the upper and lower weights is changed, the direction of travel of the raw materials can be changed.

Motor instructions:
When the motor meets the following conditions, it can continuously output the rated excitation force.
1. Vibration acceleration: no more than 7g (g: acceleration due to gravity)
2. Ambient temperature: not more than 40ºC
3. Altitude: no more than 1000m
4. Power frequency: 50Hz
5. Altitude: no more than 1000m
6. Temperature rise: less than 80K (resistance method)

Zhongding Machinery attaches great importance to international academic exchanges and cooperation, and has sent groups to study abroad many times to exchange experience and learn from each other with international production technology experts in the mineral processing industry, such as manufacturers in Canada, Russia and other countries, so as to achieve mutual wins for both parties. At present, the products have been exported to Kazakhstan, India, Indonesia, Turkey, Canada, Africa and other countries and regions, and have been widely praised! Our products are spread all over the world, and customers come from all over the world. We always maintain product quality and service first and provide customers with more and better products and technical support with a tireless spirit to ensure that the Zhongding brand serves every customer and is well-known in the corners of the world.
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