What are the reasons of belt deviation in belt conveyors?

1. Belt deviation phenomenon and causes

The fundamental cause of belt deviation is that the resultant force of the external force on the belt in the width direction of the belt is not zero, or the tensile stress perpendicular to the width direction of the belt is uneven, which results in the reaction force of the idler or roller on the belt. A component force to one side causes the belt to deflect to one side. The law of deviation of the belt is "running tight but not loose": that is, when the tightness on both sides of the belt is different, the belt moves to the tighter side; "running high but not running low": if the height of the belt on both sides is different, the belt will Move to the higher side; "Running behind, not running ahead": If the roller bracket and other devices are not installed on the vertical section in the belt running direction, but have one end in front and one end in the back (along the belt running direction), the belt It will move towards the rear end. Common deviation phenomena are as follows.

(1) The center of the nose, tail, and intermediate frame is not in a straight line, causing the belt to deviate. This situation is usually caused by installation. Since the centers of the three are not in a straight line, the longitudinal centerline of the belt is not perpendicular to the axis of the drum, causing the belt conveyor to deviate during operation.

(2) The incorrect installation position of the drum causes the belt to deviate at the drum. A belt conveyor has multiple rollers. The installation position of all rollers must be perpendicular to the center line of the belt and parallel to the horizontal plane. If the installation level of the rollers is not enough, the rollers will move axially, or one end of the rollers will be in front and the other end will be in the back. , so that the installation position of the drum is not perpendicular to the longitudinal centerline of the belt or the axis of the drum is not parallel to the horizontal plane, then the resultant force of the external force on the belt in the width direction of the belt is not zero, and the belt will deviate in the direction of the resultant force.

(3) The conveyor belt joints are incorrect, causing the middle part of the conveyor belt to deviate. Commonly used belt joints include mechanical joints and vulcanized joints. No matter which joint method is used, the joints are required to be flat. If the joints are incorrect, the tension on both sides of the belt will be inconsistent, resulting in deviation during operation. The deviation caused by the incorrect tape joint is wherever the tape joint runs, the deviation will occur there.

(4) Belt deviation caused by incorrect roller frame or loose bolts fixing the roller frame. When the belt conveyor is installed, the symmetry between the center line of the roller group and the center line of the conveyor frame shall not be greater than 3.0mm, and the upper surface of the rollers shall be located on the same horizontal plane or inclined plane. If the installation error of the roller group is too large or the fastening bolts are loose, the belt will deviate.

(5) Belt deviation caused by conveyor belt damage. The conveyor belt is easily damaged during operation. When the degree of damage on both sides of the center line of the conveyor belt is different, the stretch rate on both sides often changes. When the stretch rate on both sides is greatly different, the belts on both sides will be damaged. When the elongation is inconsistent, it is easy to cause the belt to deviate.

(6) The material unloading point is not in the middle of the conveyor belt, causing the belt to deviate. When the material unloading point is not in the middle of the belt, the load on the belt will be unevenly distributed along both sides of the longitudinal centerline due to the eccentric load. When the difference between the two is large, it will directly cause the conveyor belt to deviate during operation. If the conveyor belt does not deviate when it is unloaded, but always deviates to one side when it is heavily loaded, it means that the conveyor belt has been eccentrically loaded. At this time, the position of the hopper or conveyor should be adjusted so that the conveyor belt is evenly loaded to prevent it from wandering.

(7) Belt deviation caused by impact of cutting material. When the material falls onto the belt, the gravity and inertia of the material will impact the belt, which may cause the belt to deviate.

(8) Belt deviation caused by material accumulated on drums and idlers. The accumulation of material on the surface of the drum or roller will increase the diameter of the drum or roller, causing the tape tension there to increase, resulting in deviation.