Principle application and troubleshooting of mine vibrating screen

Principle of mine vibrating screen:

The screen box relies on two identical vibration motors to do self-synchronous rotation in opposite directions, so that the entire screen supported on the shock absorber vibrates linearly. After the material falls into the screen box from the feed end, it moves forward, loosely, and through the screen quickly. Complete the screening operation.

Composition of mine vibrating screen:

The mine vibrating screen is composed of a screen box, a vibrating motor, a vibration damping system and an underframe.

The screen box is composed of a screen frame, a screen plate, and a lining board.

The vibration motor adopts the high-performance, long-life TZDC series vibration motor as the excitation source. Adjusting the size of the vibration motor's excitation force can change the vibration amplitude of the screen machine.

The damping system is composed of rubber springs, clamps, and supports. The underframe is composed of a silo and a chassis. The vibration motor installation methods of this series of vibrating screens can be divided into upper vibration type and down vibration type, and the vibration damper installation methods can be divided into seat type or hanging type. It can also be designed and manufactured according to user needs.

Mine vibrating screen application

Mainly used in metallurgy, mining, coal, building materials, electric power, chemical industries and other industries, especially in the metallurgical industry, it has a wide range of uses. It is a commonly used screening machine for blast furnace troughs, coking plants, and mineral processing plants.

Reasons for the rapid damage of the vibrating screen

The main reasons for the rapid damage of the vibrating screen are the quality of the screen, the tension of the screen, and the problem of material feeding.

a. The quality of the screen is an important factor that causes the screen to break too quickly. If the material of the screen does not meet the screening requirements of the material, the screen will be damaged very quickly. We have listed the classification of the screen and how to choose a suitable screen in the customer's considerations when choosing a rotary vibrating screen.

b. The tension of the screen is not enough, which causes the screen to vibrate, which is usually broken or damaged along the edge of the screen or at the edge layer.

c. The screen generally has an upper screen layer and a lower stress layer. The two layers are required to be closely attached. If the screen pre-tensioning process is poor, when the stress layer at the bottom of the screen is tightened, the screen If the stratification is not tightened, the vibration distance of the screen is too large when the screen is working, and the contact part with the screen frame cannot be effectively compressed, which is also one of the reasons for the rapid damage of the screen.

d. The feeding problem of materials. Because the vibrating screen is constantly feeding materials, if too much material is fed at a time, it will hinder the normal movement of the materials on the screen, which will not only make the screen fatigue and loose, but also greatly reduce the processing capacity of the materials. Giving a large amount of material at one time will cause the load of the motor that is in unbalanced operation to increase suddenly, not only easy to damage the screen, but also easy to damage the vibration motor, so the material should be fed evenly. In the feeding method with strong impact force, the vibrating screen must be equipped with a buffer hopper. The direct impact of the material on the screen will consume the exciting force generated by the vibration source, which is more likely to cause damage to the screen and fatigue of the screen.

vibrating screen

Solution

a. First choose a reliable screen when choosing a vibrating screen;

b. Check the tension of the screen frequently;

c. Check whether the screen is compacted.

d. If it is to screen liquid, hopper or buffer can be added when there is strong impact force.

e. If there is material accumulation, find the cause as soon as possible, such as adjusting the eccentric block of the vibration motor.

Small reminder: The vibrating screen screen should pay attention to these possible problems during the installation process.

Maintenance method of vibrating screen in high temperature working environment

In the hot summer, too high temperature has become a hidden danger for the normal operation of the vibrating screen. The ambient temperature required for normal vibrating screen work is generally not more than 40 ℃, so we should not only consider it in the daily operation of the vibrating screening equipment. In production, the tolerance of the machine must also be considered.

1. When working outdoors, the vibrating screening equipment should pay attention to building a sunscreen or tent.

a. Long-term exposure to the hot sun will not only make the machine easy to wear and age, but also make the entire vibrating screening equipment too hot and unable to work normally, affecting the efficiency and quality of the screening, and severely will cause the vibrating screen components such as : The vibration motor is damaged.

b. For vibrating screening equipment working indoors or in kilns, attention should be paid to the adjustment of indoor temperature, as well as ventilation and air permeability. The ambient temperature generally does not exceed 40°C, which provides a good working environment for the vibrating screen.

2. The temperature of the vibrating screening equipment is too high. The core component of the vibrating screen-the temperature of the vibration motor is too high. What solution is the vibration motor temperature is too high?

The temperature of the vibration motor refers to the actual heating temperature of each part of the vibration motor. It has a great impact on the insulating material of the vibration motor. Too high temperature will cause the insulation to deteriorate and shorten the life of the motor, and even cause insulation damage. In order to prevent the insulation from aging and damage, the temperature of each part of the vibrating motor winding and other parts is restricted from time to time. This temperature limit is the allowable temperature of the vibrating motor.

Factors affecting the vibrating screen of sand and gravel equipment

1. The influence of material properties. Facts show that the particles of the circular vibrating screen whose material size is less than 3/4 of the screen hole size are easy to steal through the screen hole, which is called easy sieve particle. Particles larger than 3/4 of the mesh are called difficult to sieve due to the difficulty of passing through the mesh. The particle size of the material is 1-1.5 times the size of the sieve is called the barrier particle. Auxiliary screening method can be added. Auxiliary sieve with larger sieve size is used to pre-discharge the coarse product on the screen, and then screen the finer materials that contain a large amount of fine grade. There is no clear regulation on the certain proportional relationship between the allowable size of material particles and the size of the sieve hole. Cement vibrating screens generally believe that large particles should not be larger than 2.5-4 times the size of the sieve hole. The surface moisture contained in the material increases to a certain extent, and the stickiness also increases. The surface moisture of the material can make the fine particles adhere to each other into agglomerates, and attach to the large particles to block the screen holes. These reasons make the screening process more difficult, and the screening efficiency will be greatly reduced. If the material contains viscous substances (such as clay, etc.) that are easy to agglomerate, even when the moisture is low, it will stick to agglomerates, causing the fine mud to mix into the product on the screen; it will quickly block the screen holes. At this time, pre-washing should be considered. If the particle shape of the material is round, it is easier to pass through square and round holes. Most of the crushed products of electromagnetic vibrating screen are polygonal. It is not as easy to pass through square holes and round holes as through rectangular holes. Strip, plate, and sheet materials are difficult to pass through square holes and round holes, but easily pass through rectangular holes. 

2. The influence of the working parameters of the screening machine. There are mainly the following six influencing factors.

① Types of dried noodles. The working surface of the sieve usually has steel bars, steel wires, perforated steel plates, rubber, polyurethane, etc. Their influence on the screening efficiency is mainly related to their effective area. In addition, various materials have different degrees of wear resistance.

②The shape of the mesh. The application of square or rectangular mesh is good.

③Screen size. Should contact the work of the crusher and product requirements to choose.

④The movement of the sieve. The screening efficiency of various sieves is roughly as follows: high-efficiency heavy-duty sieve is greater than 90%; shaking sieve is greater than 70-80%; rotary drum sieve is 60%; fixed strip drying is 50-60%. Choose according to the situation.

⑤The width and length of the sieve. It is generally believed that the ratio of the width to the length of the sieve is 1:2.5~1:3.

⑥The inclination angle of the drying surface. The inclination angle of the vibrating screen is generally 0°~20°, and the inclination angle of the fixed bar screen is 40°~50°.

3. The influence of operating factors. In order to maintain a high screening efficiency, the feed should be uniform and continuous, and the feed volume of the vibrating screen should be moderate.

Installation of vibrating screen and maintenance method

First of all, before installation, check the site foundation and the screen installation drawing. The flatness error of the embedded steel plate is ≤3mm. The installation is carried out according to the order of the screen from bottom to top. After each link is adjusted to a preliminary qualified state, the next link is installed.

Secondly, after installing the sieve, adjust the relative position, the primary and secondary damping springs are both vertical, the motor axis should be 3-5mm below the axis of the exciter, and then spot weld the motor bracket, spring base and the embedded steel plate firmly . The rotation direction of the two motors must be opposite, and the eccentric block of the exciter is in the same phase. The vibrating screen has no-load operation for 4-6 hours, and the screen body is required to run smoothly without shaking and abnormal noise. Check the tightness of the screen plate and vibration exciter.