水泥设备振动的识别与处理

2020-09-08

Wang Zhanguang (Jiaozuo solid Cement Co., Ltd) 0 0 Introduction 0The stable operation of equipment is the basis of production. Vibration not only damages the service life of equipment, but also the direct loss of enterprise benefit. Why do enterprises with the same scale and capacity have different benefits? This is closely related to stable operation. Therefore, it is of great significance to reduce vibration and reactive power consumption. With the progress of science and technology, vibration measuring elements have been widely used in cement industry, which plays a positive role in monitoring and stable operation of cement equipment, and also provides a basis for vibration analysis. In this paper, through the analysis of vibration characteristics, the identification and treatment methods of vibration are described for the communication of peers. 1.0 analysis of equipment vibration sourceThere are many kinds and forms of vibration. But for the cement industry, it is mainly through the analysis of vibration characteristics to find out the vibration source, eliminate the cause of vibration, reduce the vibration intensity level and ensure the stable operation of the equipment. The vibration of cement equipment mainly comes from equipment support, power transmission, unbalance of rotary body, loosening of fasteners, interference of parts and system disturbance. 1.1 vibration from support The vibration of the support mainly comes from the damage of the bearing, the lack of stiffness and looseness of the equipment frame. When the inner and outer sleeves and rolling elements of the bearing appear pitting and spalling, the contact surface is not smooth, and the impact vibration will occur during operation. The sound generated by the vibration is continuous, stuffy and broken, and has obvious crushing feeling, which is more severe in the vertical direction, and the vibration value is too large. If the inner and outer sleeve of the bearing or the rolling element is broken, the impact vibration will occur at the moment when the rolling element passes through the crack If the foreign body is stuck in the bearing, it will not only cause vibration, but also emit squeal. If the foreign body stays in the raceway and forms cushion, the rolling element will vibrate when passing through it, and the noise will be dull and resistance, The vibration is manifested in that the radial direction of the cushion is too large. If the foreign matters emit friction noise along with the transportation of the shaft, once the friction and squeal are heard in the bearing, it may be that there is something wrong with the cage; when the bearing and the shaft are not concentric, the vibration is larger in the axial direction, and the noise is light or heavy, However, the load of the main engine fluctuates regularly; if the clearance of the bearing with normal wear is more than three times of the initial clearance, the vibration value will increase obviously, and the vibration direction is mainly in the vertical direction. For sliding bearings, generally, there is no sound and no vibration. Only when the clearance between the shaft and the Bush is too large, the vibration will be generated due to the whirling of lubricating oil. The direction of vibration is shown in the vertical aspect. There is another case that when the axial positioning of the rotary body is not good, the axial rotation of the rotating body will move back and forth, and the axial vibration will be caused by bumping the pad skirt. In the case of rolling bearing or sliding bearing in operation, no matter which one, the vibration value and vibration direction, from small to large, and then from large to small, are relatively regular, the peak value is stable, and the bearing noise is the same. When the stiffness of the equipment frame is insufficient, the vibration momentum of the equipment is large, and it is easy to shake left and right, and the vibration value is unstable. When the peak value is large or small, the vibration direction is also unstable, Sometimes the vertical direction is large, sometimes the horizontal direction is large, and sometimes the axial direction is large; if the base is loose, such as bearing cover, anchor and pad iron, when the degree of looseness has not affected the installation accuracy, the vibration value in the vertical direction increases. 1.2 vibration caused by power transmission process The power transmission of cement industry is mainly gear, belt, coupling and so on. In normal gear transmission, the meshing sound is relatively uniform and the vibration is relatively stable. However, in the case of bearing damage, gear pitting, tooth breakage, key cutting, shaft bending, etc., the overlap coefficient of the gear is reduced, and the meshing accuracy is reduced, and the impact will occur during the operation, and the vibration cannot be avoided, A herringbone gear reducer in our factory has broken teeth. The broken parts account for about 40% of the total length. The nickel and precision are reduced, the overlap coefficient is reduced, and the periodic noise and vibration are generated. The frequency is calculated according to the vibration direction and the speed ratio at all levels. The position of the broken tooth is determined and the load reduction is determined after the bearing capacity is checked After the spare parts were in place, they were replaced. When the bearing is damaged, the gear meshing is unstable, the impact sound is continuous, the vibration value of spur gear increases in horizontal and vertical directions, while that of helical gear increases in axial direction; when the key is cut or the key is loose, abnormal meshing occurs, The impact frequency is low, which reflects that the main engine is unstable in the number of revolutions, and the vibration direction is mostly in the vertical and horizontal directions; the gear has pitting corrosion, and the noise is continuous, stable and hard to hear; the vibration of spur gear is mainly in the vertical direction, and the helical gear is mainly in the axial direction; when the tooth is broken, the impact is very heavy, the sound is short and discontinuous, the frequency is related to the speed, and the vibration value in the vertical direction is large; the shaft is bent The results show that the gear noise is regular, the frequency is consistent with the rotational speed, and the vibration is larger in the horizontal direction and vertical direction. The vibration in belt transmission is typical caused by belt tightness and bearing damage. When the belt is too loose, sometimes it is hard and sometimes it is small, which often causes vibration, resulting in unstable rotating speed. The belt vibrates up and down and makes a beating sound. The vibration direction is shown on the connecting line of measuring belt pulley. Besides the above characteristics, the performance characteristics of bearing damage are also accompanied by Abnormal noise and vibration of bearing. The most common and prominent vibration in the transmission comes from the coupling. Because the installation of the coupling is usually at the end, or the time is tight or the tools are not in place, it is difficult to ensure the coaxiality. The operation will cause disturbance, increase the axial vibration, uneven noise of equipment at both ends, and fluctuation of load. 1.3 vibration caused by unbalance of rotating body The unbalance of rotating body of equipment in operation is generally caused by uneven ash sticking, uneven wear, bending of shaft, loosening or falling off of counterweight, etc. However, no matter which of the above reasons, the imbalance has the same performance characteristics, which is reflected in the vibration in the water square direction, and the peak value of vibration value fluctuates regularly and stably with obvious periodicity, However, the vibration value of the shaft will increase day by day after bending, which is because the shaft will become more and more curved when it is running in vibration; the cement paste is generally not reliable, With the vibration sometimes falling off, the performance of today's vibration, tomorrow may not be vibration, which is probably caused by sticking ash; when the bearing supporting the rotating body appears running ring, due to its large clearance, the centering function will disappear. If the two supports of the rotary body are connected with the coupling, the imbalance is very large, and the vibration value is especially large, which is reflected in the level After a period of time, the direction and axial direction may be improved, and it may not vibrate again after stopping the machine, but it will not last for a long time. Due to various reasons, such as the large fit clearance between the bearing sleeve and the bearing seat, the supporting bearing of the slewing body, driven by the external force, may cause the inner and outer sleeve of the bearing sleeve and the bearing seat skew, and when the stiffness of the bearing pedestal is insufficient, it will also cause the deflection of the bearing pedestal The result is that the bearing clearance is fixed in a certain direction. When it is running, it is hard and easy to operate. Strong vibration is generated in the axial direction. The vibration detection shows that the peak value is unstable, sometimes large and sometimes small, and the bearing noise is uneven. 1.4 vibration caused by looseness The vibration of the equipment is closely related to the looseness of the fasteners. When the anchor bolts are loose, the damping effect on the vibration is reduced, the equipment is bumpy, and the vibration parameters are in an unstable state. The looseness of the internal fasteners or components of the equipment is often accompanied by relatively abnormal noise. If the looseness causes imbalance, the horizontal vibration parameter increases obviously; if the looseness causes the positioning failure, which occurs in the axial direction, the axial vibration is large; if it occurs in the radial direction, the horizontal and vertical vibration increases; if the loosening causes interference, there will be obvious impact sound, and the increase of vibration parameters is shown in the interference direction. The harm of interference is very great. It will not only cause vibration, but also cause equipment collision, which will worsen the operation and even cause the machine damage and human death. It must be dealt with in time. The vibration characteristics of common bearing pedestal looseness are in vertical direction. 1.5 equipment vibration caused by unstable production system In cement industry, unstable production system is also one of the reasons for equipment vibration. The vertical mill will vibrate when the material bed is unstable, The vibration direction is mainly reflected in the vertical direction, followed by the horizontal direction, and the magnitude of vibration depends on the degree of instability of the material bed; the collapse of the preheater system will cause temporary imbalance of the impeller of the high-temperature fan, causing severe vibration in the horizontal direction, followed by the vertical direction, and even stop the motor in serious cases, causing accidents; when the rotary kiln is agglomerated, it will cause low-frequency bumping on the foundation Vibration and uneven collapse of kiln skin will cause the cylinder temperature to be higher or lower in the circumferential direction, and then cause the cylinder to bend, which will affect the transmission and produce vibration. When turning to the protruding place, the gear undercutting will make a dull undercutting sound. The vibration is shown in the horizontal direction. When turning to the concave place, the overlapping coefficient of gears will be reduced, and the loud knocking sound will be emitted. The vibration is shown in the vertical direction However, because the rotary kiln speed is slow and the vibration frequency is low, it is not easy to measure, but the vibration is strong. Vibration caused by interference 1.6The interference of moving parts occurs between moving parts and moving parts, and also between moving parts and stationary parts. If there are many running parts in the reducer and roots blower, once the positioning of the internal parts fails and the running clearance changes, there will be collision or friction interference between the running parts. The vibration caused by this is inevitable, and the vibration direction is the same as the impact direction. When the inherent motion space between the moving parts and the static parts changes and exceeds the limit range, it will cause the interference of the components and cause the equipment to vibrate. For example, the bending of the kiln head and the kiln tail will damage the kiln door cover and the kiln tail smoke chamber, resulting in vibration; when the bolt of the end cover of the pipe mill retreats, it will touch the foundation and produce vibration. 2.0 treatment of equipment vibrationAfter understanding the performance characteristics of various types of equipment vibration, the causes and parts of vibration can be preliminarily or accurately judged according to the experience and with the help of instruments. According to the structural characteristics of the equipment, the maintenance scheme can be formulated and treated. 2.1 vibration treatment caused by equipment supportIn case of shaking or vibration of the equipment during operation, check whether the anchor bolt of the equipment is loose, and if it is loose, it must be tightened. If the tightening is not tight, the anchor bolt may be broken or pulled out, so the anchor bolt must be regenerated; if the secondary grouting layer is cracked and the pad iron is loose, the pad iron should be tightened first and then tightened. The tightening process must be carefully observed to avoid causing large deformation of the engine base; if hard impact is found during fastening, and With the tightening and vibration aggravating, the bolt should be loosened and other bolts should be tightened step by step. After other bolts are tightened, the bolt should be tightened. Before fastening, the gap between the base and the equipment should be tamped with iron sheet. For example, when fastening the four corners of the motor, when

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