The cause and solution of the failure of vibrating screen
Vibrating screen is widely used in mining, metallurgy, coal, building materials, chemical industry, cement, glass, grain, medicine and other industries because of its simple structure, small footprint, easy installation and operation, easy maintenance, low noise and reliable performance.
During the use of vibrating screen, many problems can be caused by improper design, manufacture or improper use of the user. In addition to mechanical failures, most abnormal operating parameters such as vibration amplitude, direction angle, inconsistent, horizontal swing is too large, material deviation, mixing, spinning and retention, resulting in decreased efficiency of screening treatment, will even cause the screen frame, screen box fracture, bearing damage and other serious problems. This paper mainly introduces the causes of abnormal vibration parameters and the solutions.
Abnormal one: inhomogeneous feed leads to partial load, even on the side of the screen.
The solution: to change the feeding mode of the equipment and give the material evenly to ensure the screening efficiency and the quantity of the equipment.
Abnormal two: a sieve plate, such as an untensioned or sieve, which is damaged, and produces two vibrations or mixtures.
The solution: replacing the damaged screen mesh or sieve plate, tensioning screen mesh or sieve plate, eliminating the relative motion between sieve plates and sieves, and avoiding the two vibration.
Abnormal three: the damping spring has too much difference in fracture or stiffness
The solution:from dynamic analysis, we can see that the size of spring stiffness will affect the working frequency of vibrating screen, and the working frequency of vibrating screen will also affect the screening efficiency. When the working frequency is determined, if a spring with different stiffness is adopted, the amplitude stability of the vibrating screen will be affected. And using the spring with different stiffness, the vibration frequency of the two is distinctly different. Change the damaged spring to ensure that the spring stiffness is consistent.
Abnormal four: single motor operation or double motor not parallel, no reverse operation
The solution: the operation of single motor is strictly prohibited, and it is very easy to cause motor overload. The two motors are in parallel and run in reverse, and self synchronization is realized.
Abnormal five: the resonance of the working frequency of a sieving machine and a certain fixed frequency produces resonance
The solution: frequency converter can be used to change the working frequency to avoid resonance.
Abnormal six: the assembly of the vibrator or the vibration motor is incorrect, and the angle of the two groups of eccentric blocks is inconsistent
The solution: that the two groups of vibrators can lead to abnormal parameters because of different exciting forces or inconsistencies in the direction. In fact, the direction of the resultant force of the exciting force depends entirely on the eccentric position of the eccentric block. If the angle between the two groups of eccentric vibrator, vibrating direction angle and vibration force is different, vibration sieve will produce torsional vibration, the magnitude and direction of the screen surface in different parts of the material velocity is different, the material deviation, spin and retention phenomenon, resulting in the screening efficiency and processing capacity, the sieve body strength decreased.
It is possible that the vibration direction angle of the sieving box is inconsistent.
The eccentric block angle of the vibrator on both sides of the A. box is not consistent, and the eccentric block on both sides should be adjusted so that the angle of the eccentric block is the same.
The bearing of one end of B. exciter is damaged, and the exciting force on both sides is inconsistent, and the exciter should be dismantled. The following points should be paid attention to when dismantled:
1.The disassembly of the vibrator should be carried out at the clean site.
2.All the parts before the assembly must be cleaned up to remove the burrs.
3.The inner and outer ring of the bearing can not be struck directly.
4.Before assembly, all the assembly surfaces should be coated with lubricating oil, such as butter.
5.Check the seal carefully, if there is aging or breakage, change it in time.
6.Load a proper amount of compound specified lubricating oil;
7.When the Y seal is assembled, the end face should be paid attention to.
8.All bolts are fastened according to regulations and fastened every one or two days at the initial stage of installation for more than three consecutive times.
Abnormal seven: the vibrating screen is not installed correctly and the foundation is not flat
The solution: the installation of the vibrating screen is very important for its correct operation. When adjusting, the four supporting devices can be taken as the benchmark, or the sieves as the datum. The level is measured by the horizontal instrument, and then adjusted repeatedly until the level is up under the support spring base.
Abnormal eight: the shafts of the vibrator deviate from the center of the drive shaft too much
The solution: generally higher than the 2mm driver allows the vibrator Axis axis, if too high, will cause the screen body twist, resulting in abnormal parameters. The adjustment method is: the first screen box leveling, and make the center vibrator shaft than the transmission center.
The working conditions of the field are complex, and the abnormal operation may be the coexistence of a variety of factors. Before the analysis of the reasons, we must first understand the use of the equipment, whether there are illegal operations. Then one by one, the analysis of the cause, in order to remedy the problem.