How to choose the right vibrating screen?

The vibrating screen is one of the indispensable equipment in the coal mine production line. The working efficiency of the vibrating screen also affects the production efficiency of the coal mine production line. As an important screening equipment, the screening effect of the vibrating screen will affect the use value of the product. Therefore, it is very important to choose the appropriate vibrating screen equipment. Here are some factors to consider when choosing a vibrating screen:

First, the characteristics of screening materials

When selecting a vibrating screen, the characteristics of the materials to be screened should be considered, including the content of the material under the sieve, the content of the difficult-to-screen particles, the moisture content of the material, the shape and specific gravity of the material, and the content of clay and other characteristics.

Linear Vibrating Screen

Second, the structure of the vibrating screen

When selecting a vibrating screen, factors such as the screen area, the number of layers, the shape, size and area ratio of the screen hole, as well as the movement mode, vibration frequency and amplitude of the vibrating screen should also be considered.

The screening efficiency of the vibrating screen is related to the movement form of the screen surface, so the screening efficiency of the fixed screen is low, and the screening efficiency of the moving screen is relatively high.

For the moving screen, the vibration of the particles on the screen surface is close to the direction of the vertical screen holes, the vibration frequency is high, and the screening effect is better; if the particles slide in the direction of the screen surface, the screening effect is relatively poor.

High frequency dehydration vibrating screen

Third, screening purpose

According to different screening purposes, different types of vibrating screen need to be selected, such as:

If the material needs to be pre-screened, a circular vibrating screen is generally used; large-scale vibrating screen, probability screen, etc. are used for grading and screening of crushed materials; linear vibrating screen is better for de-intermediation and dehydration treatment of materials; if necessary The material is desilted and sand cleaned, and the probability screen is used.

Fourth, mineral processing requirements

When choosing a vibrating screen, it is also necessary to consider the processing capacity of the production line, the screening method, the screening efficiency and the inclination angle of the vibrating screen.

In the actual production of the coal mining industry, it is necessary to select the larger sieve size and effective screening area as much as possible according to the actual situation and meet the requirements of the particle size of the manufactured sand products, and select the appropriate sieve shape and sieve surface opening. High-efficiency non-metal screen surface to improve the screening effect and work efficiency of sand and gravel materials.

Safety operation rules for high frequency dewatering vibrating screen

The normal operation of the equipment can only be ensured by operating the vibrating screen in accordance with the correct safety regulations during the use of the vibrating screen. Today, the vibrating screen manufacturer will introduce to you the safety operation regulations of the high-frequency dewatering vibrating screen that we need to abide by!

Precautions for the installation of high-frequency dewatering vibrating screen

Linear vibrating screen

(1) When the vibration exciter is installed and repaired, it shall not be beaten hard or have a different phenomenon, and ensure that the original bearing is used and shall not be interchanged.

(2) The thickness and quantity of the eccentric block or counterweight plate attached to the eccentric block must be the same, and the radial clearance of the bearing should be C3 grade.

(3) The connection between the universal joint and the vibration exciters on both sides must be concentric, the eccentric blocks on both sides are in the free plumb position, and the universal joint connecting bolts can pass through smoothly; if there is any deviation during installation, check the universal joint Whether the joints at both ends of the section are concentric, do not swing the eccentric block angle for installation.

(4) The vibrating screen should be installed with springs with the same stiffness. The spring stiffness on both sides of the feeding end and the discharging end should be as consistent as possible, and the allowable height difference does not exceed 3mm.

(5) Both sides of the support seat of the rubber spring of the vibrating screen should be in the same horizontal plane, and the error is between 2-4mm to ensure that the materials on the screen surface advance evenly.

(6) When using electric welding to install or disassemble parts, the ground wire must be directly fixed on the welded workpiece and as close as possible to the welding point, and the welding current must not pass through any bearings or joints.

(7) In principle, welding should not be performed on the side plate. Depending on the current environment, if connecting components are required, the side plate should be drilled and then connected with bolts.

(8) The universal joint must be concentric, and a protective device must be installed to prevent it from breaking and falling and hurting people.

Precautions for the use of high frequency vibrating screen

High frequency dehydration vibrating screen

1. Understand equipment related knowledge

The operator should ensure that the operator understands the scope of use and technical performance parameters of the equipment; has sufficient understanding and mastery of the structure, principle and common sense of maintenance of the equipment; familiar with the process flow and equipment control of the system; keep in mind the high-frequency vibrating screen Safe operating procedures.

2. Check before operation

(1) The area around the equipment should be checked to ensure that no personnel are left behind to avoid personal injury when the machine is turned on.

(2) Check whether the feeding, discharging chute and under-sieve chute are unblocked.

(3) Check whether the sieve plate and bead bolts are loose, as well as the wear of the sieve plate.

(4) Check whether the V-belt and flexible sheet are in good condition, whether the tightness is appropriate, and whether there is damage. If there is damage, it should be replaced in time.

(5) Check the connection between the universal joint and the connecting bolts of the transition pressure plate, and whether the rubber spring is damaged.

(6) Follow the sequence of the process system to ensure that the empty screen is started and all safety equipment is in a safe and operable state.

(7) The vibrating screen must be started under no load, and the material can be fed after the amplitude is stable.

3. Observation during operation

(1) Observe the distribution of materials on the screen, and make appropriate adjustments if necessary to ensure uniform distribution of materials on the screen.

(2) Observe whether the vibration frequency and amplitude of the vibrating screen are abnormal, and whether the operation is stable.

(3) Check the temperature of the motor, vibration exciter and transmission bearing seat.

(4) Observe whether there are abnormal noises such as collisions and knocks during the operation of the vibrating screen. If it is found, it must be stopped in time.

(5) Check the vibration damping of the rubber spring.

(6) Under normal operating conditions, the bearing temperature should not exceed 45 degrees.

4. Parking precautions

(1) The amplitude of over-resonance of the vibrating screen during startup and shutdown is 5 times of normal, and it should not exceed 8 times.

(2) In any case, as long as an accident occurs, the equipment should be stopped first before contacting the centralized control room and relevant positions.

(3) Under normal circumstances, the sequence of the process system should be followed, and the vibrating screen should be stopped under no load, and must not be stopped with materials.

(4) Pay attention to the large-amplitude swing when parking to ensure the safety of the equipment, and remember to abide by the safety operation rules of the high-frequency vibrating screen.

Precautions for maintenance of high frequency vibrating screen

(1) After replacing the drive belt, it is necessary to re-check whether the outer end faces of the two pulleys are on the same level.

(2) After the overhaul is completed or the electrical components are replaced, the steering must be checked to ensure the safe use and operation of the vibrating screen.

(3) After the equipment is overhauled, the vibration exciter must be turned by hand, and the main shaft should rotate flexibly without friction and jamming.

(4) Regularly check the connection parts of each bolt, which must be firm and reliable, and all bolts must not have any looseness.

(5) Regularly check the wear and tear of the sieve plate.

(6) Check the side plates and beams of the vibrating screen once a month.

(7) Regularly check the rubber spring, V-belt, flexible connecting piece and universal joint.

(8) Lubricate each lubricating point and replace the lubricating oil according to the equipment requirements.

(9) Overhaul the vibrating screen once a year, remove all the vibrating screens for cleaning and oil change, carry out a single careful inspection of the bearings, and replace them if necessary.

The above is a very detailed introduction to the safety operation rules of high-frequency vibrating screen, mainly about the operation rules of installation, use, maintenance and other aspects. We can make a relevant understanding. At the same time, if you encounter any problems in operation, you can contact us

Introduction of Calculation and Measurement Method of Vibrating Screen Screening Efficiency

When using a vibrating screen, the screen has two important process indicators: one is the processing capacity, which is a quantitative indicator that indicates the screening work. Another is the screening efficiency, which is a quality indicator that indicates the screening work. Among the products on the sieve, the more the number of fine grades that do not pass through the sieve holes, the worse the sieving effect is. In order to quantitatively evaluate the completeness of sieving, the index of sieving efficiency should be used.

Screening efficiency of vibrating screen: It is an indicator of the working quality of the screen, indicating the degree of screening operation and the quality of screening products. It is usually expressed as a percentage by the ratio of the weight of the undersize product obtained during sieving to the weight of the fractions smaller than the sieve size contained in the raw material.

Because it is difficult to weigh the product of the screening operation in actual production. However, it is possible to perform sieving analysis on each product of the screening operation, thereby measuring the percentage of fine fraction weight of the sieve size through which the ore feeding, the under-screen product and the over-screen product pass through the screening operation. How to calculate the screening efficiency of vibrating screen?

Arc vibrating screen

The screening efficiency can be calculated by the lower ore screen: E=β(α-θ)/α(β-θ)*100%.

α——The content of the particle size smaller than the sieve size in the raw material;

β——The content of the particle size smaller than the sieve size in the product under the sieve;

θ——The content of particles smaller than the sieve size in the product on the sieve.

Example: a vibrating screen with a sieve hole of 15 mm, after sampling and sieving analysis, it is known that the 15-0 mm particle size accounts for 50% of the sieved materials, and the product on the sieve contains 8% of the particle size, and the sieving efficiency is calculated. how many?

α (content of the raw material smaller than the size of the sieve size) = 50%, θ (the content of the product on the sieve smaller than the size of the sieve size) = 8%

So: E=100(α-θ)/α ore screen (100-θ)*100%=100(50-8)/50(100-8)*100% =91.3%

High frequency dehydration vibrating screen

Because the screening efficiency of vibrating screen is affected by many factors, it depends on what material to be processed, the composition of the material, the purpose of screening and the moisture content and viscosity of the material.

Determination method of sieving efficiency

Take samples every 15-20 minutes in the material flow entering the sieve and the material flow on the sieve. Sampling should be carried out continuously for 2-4 hours. The average sample obtained is sieved in the inspection sieve. The sieve hole of the inspection sieve is consistent with the The mesh size of the sieve used in production is the same. The percentage content α and θ of the grades smaller than the sieve size in the raw material and the product on the sieve are respectively calculated, and the sieving efficiency can be calculated by substituting them into the formula.

If there is no inspection sieve with the same size as the sieve, you can use a set of sieves for sieving analysis, draw the results into a sieve analysis curve, and then calculate the percentage content of this grade from the sieve analysis curve. a and theta.

To sum up, the low efficiency of vibrating screen is affected by many factors. If the screen is worn, or the quality of the screen surface is not high, particles larger than the screen size will enter the product under the screen. If the screening efficiency increases abnormally and sharply, it is possible that the screen is severely worn, or the screen surface quality is not good. High, the sieve size does not meet the quality requirements, resulting in too many particles larger than the sieve size.

How to prevent the vibrating screen from rusting?

In the mining sand and gravel industry, vibrating screens are often used to screen materials. Generally, the production in this industry is in an open-air environment, so sometimes bad weather is encountered. The main screening object in the vibrating screen, the screen, is sometimes inevitably affected by rain, etc., which will cause the screen to rust. However, the rust of the vibrating screen will not only affect the production efficiency of the vibrating screen, but also It affects the production efficiency of the entire machine-made sand production line, so when rust occurs, it must be dealt with in time.

How to prevent the vibrating screen from rusting

High frequency dehydration vibrating screen

1. Select high-quality equipment

Choose a vibrating screen equipment with good material quality, and the quality of its accessories is also good, and it is not easy to rust. Therefore, high-quality screen material can largely avoid the occurrence of rust.

2. Cover the protective layer

Set a protective layer on the screen of the vibrating screen, for example, apply vaseline, oil, paint, etc. on the screen, or use hot-dip, electroplating, sputtering and other methods to coat the screen with corrosion-resistant metal, usually forming an oxide film, isolating The air will corrode the screen, and then do a good job of rust prevention and reduce the rust of the screen. Because the rust of the screen is mainly due to the chemical reaction between its surface and the moisture in the air, so in order to do a good job in the anti-rust work of the screen, the screen of the vibrating screen must be isolated from the air.

Linear vibrating screen

3. Pay attention to cleaning the screen

Do a good job of cleaning the vibrating screen to ensure the screening effect of the screen. Do a good job of removing dirt and grease. The surface of the vibrating screen will adhere to grease or dirt after a period of use. If it is not cleaned in time, it will also cause the screen to rust. Therefore, after using the vibrating screen, the impurities on the screen should be cleaned in time. . It can be washed with soap, warm water or weak detergent. If there is oil stain, it can be scrubbed with a soft cloth and then washed with detergent.

If there is rust on the surface of the vibrating screen, it can be cleaned with rust-removing acid such as nitric acid and other rust-removing items; if a rainbow pattern appears, it can be cleaned with warm water mixed with neutral detergent.

4. Pay attention to the placement of the equipment

Pay attention to the placement of the vibrating screen equipment. The equipment should be placed in a dry and cool place to avoid direct contact with moisture. The reason why the vibrating screen is easy to rust is because of the open-air production method used. In order to fundamentally solve the problem of rusting of the vibrating screen, closed production can be used, or the vibrating screen can be placed in a relatively clean and dry environment, which can Reduce the contact between the vibrating screen and the moisture in the air, solve the rust problem of the screen, and also reduce the dust pollution problem of the vibrating screen.

The screen is an important part of the vibrating screen. The screen will be in direct contact with the material. If the screen is rusted, it will affect the screening efficiency of the vibrating screen. Therefore, it is necessary to take certain measures to prevent the screen from rusting. , which can also ensure that the vibrating screen equipment plays a better screening role.

What are the precautions for daily maintenance of linear vibrating screen?

Linear vibrating screen is a kind of vibrating screen, which is widely used in many industries. The equipment is simple to use and has good effect, so it is favored by many users. Although the linear vibrating screen is easy to use, it still needs our careful maintenance during use.

Usually, the linear vibrating screens we see are driven by dual vibration motors. When the two vibration motors are synchronized and counter-rotated, the exciting force generated by the eccentric block cancels each other in the direction parallel to the motor axis, and when the vertical vibration The direction of the motor shaft is stacked as a resultant force, so the motion 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 self-gravity of the material, the material is thrown up on the screen surface and moves forward in a straight line, so as to achieve the purpose of screening and grading the material. In the process of use, the equipment needs frequent maintenance. During the maintenance, the following points need our attention.

Linear Vibrating Screen

1. In the early stage of operation, check the bolts at least once a day to prevent loosening.

2. When it is used again after being left for a long time, the insulation resistance should be measured, which should be greater than 0.5 megohm for the measurement of a 500-volt megger.

3. The vibrating screen and the screen carrier are equipped with special damping rubber, so as to achieve the longest service life. The rubber strip should be properly located between the two, and the damaged damping rubber strip should be replaced.

4. When the rotation direction of the motor does not meet the requirements, adjust the phase sequence of the power supply.

Linear vibrating screen

5. After accumulative running for 1500 hours, the bearing should be checked, and if there is serious damage, it should be replaced immediately.

6. The lead angle of the tension plate of the linear vibrating screen can be adjusted. To install the screen, the lead angle bolts should be loosened so that the upper and lower screens can be moved and placed properly. The first tensioning screws and bolts tighten the plate and give slight pressure to drive the lead angle. , until the screen to the screen, firmly tighten the screw direction angle.

7. When replacing the weaving net, it should be ensured that the gap between the side plate of the screen box and the screen is equal to the first tightening and flattening, and the tension is maintained evenly with the tensioning plate, and the tension is checked. If the contact is insufficient, tight or uneven, it is a big cause of premature screen damage.

8. When disassembling the vibrating screen, it should be disassembled carefully from the outside to the inside to avoid artificial damage to the parts. In particular, to eliminate the balance wheel, it must be removed. The removed parts must be cleaned one by one, and carefully inspected. If any damage is found, it should be repaired or replaced in time.

The above are some precautions for the daily maintenance of the linear vibrating screen. In the maintenance process, correct methods must be taken to avoid the occurrence of problems.