Thread Content
In the design of belt conveyors, the selection of tapered drums is often a consideration. The main criterion for choosing conveyor drums is their diameter; using drums with a larger diameter is highly beneficial for the operation of the conveyor belt. However, as the drum diameter increases, the mass of the driving drum, the reduction ratio of the drive unit’s reducer, as well as the mass and size of the reducer all need to increase accordingly. Shanghai Yuyin Machinery advises users to consider the following factors when choosing a drum diameter: (1) the bending stress of the conveyor belt as it wraps around the drum ； (2) The frequency of belt bending is related to the guiding method, the number of rollers it passes around, the transportation distance, and the speed ； (3) Maximum or average specific pressure between the conveyor belt and the drum surface ； (4) Belt allowable strength utilization rate, which is the percentage of the maximum tension on the conveyor belt to its allowable tension ； (5) Installation location and operating conditions of belt conveyors ； (6) Drum rubber coating and deformation amount of the coating ； The principle behind determining the drum diameter is that when the tensile stress on the conveyor belt is high, the additional bending stress should be lower ； Conversely, when the tensile stress is low, a slightly higher bending stress is allowed, allowing for the use of a smaller drum diameter. The thickness of the drum shell depends on factors such as the diameter of the drum, the length of the drum body, the tension of the conveyor belt, and wear during braking. Calculating the thickness of the drum shell is very difficult, and the calculated values are generally on the low side. Moreover, to ensure wear resistance and ease of manufacturing, the thickness of the drum shell is usually made relatively thick. After determining the thickness of the cylindrical shell, its strength is checked; since the shell is subjected to normal and tangential loads, and the magnitude of these loads varies along the circumference of the drum. At present, there is no accurate method for calculating cylindrical shells. Although finite element analysis can yield relatively precise results, the lack of specialized general-purpose programs for calculating belt conveyor drums means that finite element analysis can only be applied to individual drums. For shell structures with soft webs, the maximum stress generally occurs in the middle of the shell’s length and on the outer side of its thickness; under normal circumstances, this stress can be expressed using approximate values with sufficient accuracy.