Research On Traveling States Of Handled Material And Indentation Resistance Of Pipe Belt Conveyor

Pipe belt conveyor is widely used in the fields of bulk solid handling, its cross-section shape of belt and format of idler group is distinct to trough belt conveyor, which brings many new research subjects to the application of belt conveyor. The increase of the interaction between belt and material due to pipe shape belt, the transverse bending tension of belt, the special idler group and the relatively large number of idlers make the traveling states of handled material and traveling resistance especially indentation resistance of pipe belt conveyor different from trough belt conveyor. The traveling states of handled material and traveling resistance are the two problems demanding urgent solution of pipe belt conveyor.The traveling states of handled material are simulated by EDEM, and the velocity distribution of material flow is given and motion of handled material is observed visually. According to traveling states of handled material of the different angle of inclination, the limited angle of inclination of pipe belt conveyor is given, and the force and contact area increase between belt and material due to wrap of belt and material are the reasons of the increase of limited angle of inclination of pipe belt conveyor. The force between material and pipe belt is given, and on the base of this, the normal force of the idler due to material gravity is given.Indentation resistance is caused by the normal force between idler and belt; it is the biggest part of traveling resistance of pipe belt conveyor. In the calculation of the indentation resistance of pipe belt conveyor, the idler is considered to be rigid, and Maxwell model is used to model viscoelastic properties of the lower rubber of pipe belt. A two-dimentional model of idler and pipe shape belt contact model is established, ignoring shear stress and inelasticity of the rubber. The stress distribution of the contact surface between idler and belt is obtained. The indentation resistance is the integral of stress distribution to the axis of idler. The indentation resistance of a specific pipe belt conveyor is calculated and the model is proved to be correct by comparing the calculation results of indentation resistance with the results of CEMA6. According to the model of indentation resistance the affect of indentation resistance is analyzed, such as normal force of idler, thickness of the lower rubber of belt, the diameter of idler and the diameter of pipe.The calculation of Secondary resistance of pipe belt conveyor takes the same method of trough belt conveyor, and it is calculated by the method of multiplying the main resistance with the secondary resistance coefficient. According to the analysis of the basement of secondary resistance coefficient, this method of calculating the secondary resistance is proved to be imprecise. Calculation error of this method is given by the calculation of an example. The secondary resistance is proposed to be calculated by adding each component of secondary resistance together.According to the analysis of characteristic of motor and power supply, and the allocation and control of driving device, the conclusion that in the calculation of efficiency voltage drop and the power balance coefficient should not be taken into account is made.