Common fault analysis of the hottest belt conveyor

Analysis of common faults of belt conveyor

belt conveyor is widely used in wharf, power plant, metallurgy, grain and other industries as bulk material transportation machinery. When purchasing, designing, manufacturing, installing and using belt conveyor equipment, some new users do not know it very well. From the perspective of users, this paper analyzes and explains the causes and treatment methods of common faults of belt conveyor equipment

1. As an environmentally friendly material that can replace the traditional coating, the belt conveyor leather is free from spraying. Belt deviation is the most common fault when the belt conveyor is running. Pay attention to the dimensional accuracy of installation and daily maintenance. There are many reasons for deviation, which need to be handled differently according to different reasons

1.1 adjust the belt conveyor bearing idler group

when the idler group deviates in the middle of the whole belt conveyor, the position of the idler group can be adjusted to adjust the deviation; During manufacturing, long holes are machined in the mounting holes on both sides of the idler group for adjustment. Which side of the belt is biased, which side of the idler group moves forward towards the forward direction of the belt, or the other side moves backward. If the belt deviates in the upward direction, the lower part of the idler group should move to the left and the upper part of the idler group should move to the right

1.2 installation of belt conveyor centering idler group

there are many types of centering idler group, such as intermediate rotating shaft type, four connecting rod type, vertical roller type, etc., which adopts blocking or idler rotation in the horizontal plane to block or generate lateral thrust to make the belt automatically centripetal to achieve the purpose of adjusting belt deviation. Generally, it is reasonable to adopt this method when the total length of the belt conveyor is short or the belt conveyor operates in both directions, because the shorter belt conveyor is easier to deviate and is not easy to adjust

1.3 adjust the position of the driving drum and the reversing drum of the belt conveyor

the adjustment of the driving drum and the reversing drum is an important part of the belt deviation adjustment. Because a belt conveyor has at least 2 to 5 rollers, the installation position of all rollers must be perpendicular to the centerline of the length direction of the belt conveyor. If the deviation is too large, it will inevitably deviate. The adjustment method is similar to that of adjusting the idler group. For the head drum, if the belt deviates to the right side of the drum, the bearing seat on the right side should move forward. If the belt deviates to the left side of the drum, the bearing seat on the left side should move forward. Correspondingly, the left bearing seat or the right bearing seat can also be moved backward

1.4 belt conveyor tension adjustment

belt tension adjustment is a very important part of belt conveyor deviation adjustment. In addition to being perpendicular to the belt length direction, the two reversing rollers on the upper part of the tensioning position of the heavy hammer should also be perpendicular to the gravity vertical line, that is, to ensure that its axis centerline is horizontal

1.5 the influence of the blanking position at the transfer point of the belt conveyor on the belt deviation

the blanking position of the material at the transfer point has a great influence on the belt deviation, especially when the projection of the two belt conveyors on the horizontal plane is vertical. Generally, the relative height of the upper and lower belt conveyors at the transfer point should be considered. The lower the relative height is, the greater the horizontal velocity component of the material is, and the greater the lateral impact on the lower belt is. At the same time, it is difficult for the material to be centered. The material on the cross section of the belt is deflected, which eventually leads to belt deviation

1.6 adjustment of the deviation of the two-way running belt conveyor

the adjustment of the deviation of the two-way running belt conveyor is much more difficult than that of the one-way belt conveyor. In the specific adjustment, you should adjust one direction first, and then adjust the other direction. When adjusting, carefully observe the relationship between the belt movement direction and the deviation trend, and adjust it one by one

2. Scattering of belt conveyor

scattering of belt conveyor is a common problem, and the reasons are various. We should strengthen the daily maintenance

2.1. Spreading at the transfer point

the spreading at the transfer point is mainly at the hopper, guide chute, etc. If the belt conveyor is seriously overloaded, the material retaining rubber skirt of the guide groove of the belt conveyor is damaged, and the steel plate at the guide groove is designed to be far away from the belt, and the rubber skirt is relatively long, so that the materials rush out of the guide groove

2.2. Scattering when the concave belt is suspended

in the concave belt section, when the curvature radius of the concave section is small, the belt will be suspended. At this time, the grooving condition of the belt will change, because the belt has left the grooved idler group, and the groove angle will generally become smaller, so that some materials will be scattered. Therefore, in the design stage, a larger radius of curvature of the concave section should be used as much as possible to avoid this kind of situation

2.3. Scattering when the belt deviates

the scattering when the belt deviates is because the height of the two edges of the belt changes during operation, one side is high and the other side is low, and the materials are scattered from the low side. The treatment method is to adjust the belt deviation

3. Abnormal noise of belt conveyor

when the belt conveyor is running, its driving device, driving drum, reversing drum, and idler group will make abnormal noise. According to the abnormal noise, the fault of the equipment can be judged

3.1. Noise when the idler is seriously eccentric

abnormal noise often occurs on the idler when the belt conveyor is running, accompanied by periodic vibration. Especially the return idler, because of its large length, self weight, noise is also relatively large. There are two main reasons for noise. First, the wall thickness of seamless steel pipes used to manufacture idlers is uneven, resulting in large centrifugal force. Second, during machining, the deviation between the center of the bearing holes at both ends and the center of the outer circle is large, resulting in excessive centrifugal force

3.2. Noise when the two shafts of the coupling are not concentric

abnormal noise emitted at the coupling between the motor and the reducer at the high-speed end of the driving device or the coupling with the brake wheel. This noise is also accompanied by vibration with the same rotation frequency as the motor. When this noise occurs, the position of the motor reducer should be adjusted in time to avoid the fracture of the reducer input shaft

3.3. Abnormal noise of the reversing drum and the driving drum

the noise of the reversing drum and the driving drum is very small when they work normally. When abnormal noise occurs, the bearing is generally damaged, and the bearing seat makes a cluck. At this time, the bearing should be replaced

4. Shaft breakage of reducer

the shaft breakage of belt conveyor reducer occurs on the high-speed shaft of reducer. The most common is that the first stage of the reducer is the high-speed shaft of the vertical bevel gear shaft. There are two main reasons for shaft breakage

4.1. The strength of the high-speed shaft of the reducer is not enough in the design

this usually occurs at the shaft shoulder. Because there is a transitional fillet here, fatigue damage is very easy to occur. If the fillet is too small, the reducer will break the shaft in a short time. The fracture after shaft fracture is usually flush. In this case, the reducer should be replaced or the design of the reducer should be modified

4.2. The high-speed shaft is not concentric

when the motor shaft is not concentric with the high-speed shaft of the reducer, the radial load on the input shaft of the reducer will be increased, the bending moment on the shaft will be increased, and the shaft will be broken during long-term operation. During installation and maintenance, its position should be carefully adjusted to ensure that the two shafts are concentric. In most cases, the motor shaft will not break, because the material of the motor shaft is generally 45 steel, the motor shaft is relatively thick, and the stress concentration is better, so the motor shaft usually will not break

4.3 shaft breaking under dual motor drive

dual motor drive is equipped with two reducers and two motors on the same drive drum. When the high-speed shaft of the reducer is designed or the allowance is small, it is easy to break the shaft. In the past, hydraulic coupling was not used for belt conveyor drive, which was easy to happen, because it was difficult to ensure the speed synchronization and force balance of the two motors during startup and operation. At present, most of the hydraulic couplings have been used, and the shaft breaking phenomenon rarely occurs, but attention should be paid to not overfilling the coupling during use, so as to make it have the effect of limited torque and improve the service life of the coupling

5. The service life of the belt is short

the service life and service condition of the belt are related to the quality of the belt. When the belt conveyor is running, it should ensure that the sweeper is reliable and easy to use, and there should be no materials on the return belt. If the above contents cannot be guaranteed, it will happen that the materials on the return belt enter the driving drum or reversing drum with the return belt, and the belt will be damaged by the materials and the vulcanized rubber layer on the surface of the drum will be damaged. There will be cracks on the belt, reducing the service life of the belt. The manufacturing quality of belts is a matter of concern to users. After a certain model is selected, its manufacturing quality shall also be assessed. The state has a special quality appraisal institution to inspect it. Generally, appearance inspection can be carried out to see whether there is cracking and aging, and whether the storage time after manufacturing is too long. In case of any of the above situations, the buyer shall not purchase. At first, the cracked belt is often damaged after a short service time

6. Influence of curvature radius of convex concave section on belt conveyor

6.1 The convex section of the belt cross-section is arched in the middle

the convex section of the belt conveyor often occurs in the middle of the belt cross-section direction, that is, the central bulge. And the belt will be discounted, and the damage degree of the belt will be aggravated after entering the direction changing drum or the driving drum after stacking. The main reason for arching and discounting is that the tension value of the unit length in the middle and outside of the belt cross section is too large, which makes the belt slide to the middle to form arching or discounting. The difference of tension value per unit length is related to the curvature radius of convex segment and the groove angle of idler. The larger the groove angle is, the smaller the curvature radius of the convex segment is, and the more serious the camber and discount are. When the groove angle of the belt conveyor is greater than or equal to 40 degrees, arch camber and discount can occur even in the groove angle transition section of the head or tail idler of the straight section of the belt conveyor. At this time, reduce the groove angle or lengthen the distance of the transition section length to make the belt groove angle transition slowly. For the convex belt conveyor, the radius of curvature of the convex segment should be increased as much as possible and the groove angle of the idler should be reduced under the condition of meeting the conveying capacity

6.2. The convex belt is clamped between the flat roll and the inclined roll

the situation that the belt is clamped between the flat roll and the inclined roll of the idler group generally occurs on the mobile bulk material transportation machinery. For example, the ship published a prospective research report on the mechanical tests and clinical results of 120 patients with this device, the stacker reclaimer. This phenomenon is easy to occur when the cantilever beam root of this kind of equipment is bent down. At this time, it is also equivalent to the convex segment of the belt. Due to the limitation of the geometric position and size, it is difficult to achieve the size required by the radius of curvature of the transition convex segment. If the belt is located at the root of the cantilever, if it only passes through oneortwo groups of idler groups to form convex segments, the belt will be stuck between the flat and inclined rollers of the idler group. The solution is to change the convex segments formed by oneortwo groups of idlers here into fourorfive or more groups

6.3. When starting the concave section, the belt will bounce up and be blown away by the wind

if there is no material on the belt during starting the belt conveyor, the belt will bounce up in the concave section, but the system will be triggered by the ultraviolet light source that can be detected in the visible spectrum, and the belt will be blown away in windy weather. Therefore, it is best to add a belt pressing pulley at the concave section of the belt conveyor to prevent the belt from bouncing up or being blown away by the wind

7. Belt slipping

7.1 fixture requirements are also very high Belt slip of belt conveyor with heavy hammer tensioning device

when the belt conveyor with heavy hammer tensioning device slips, the counterweight can be added to solve it until the belt does not slip

7.2. Spiral tension