Research On Main Resistance Of Pipe Conveyors

Pipe conveyor is a special kind of belt conveyors developed from traditional trough belt conveyors. At present, the usual design method of pipe conveyor is the same as that of traditional trough belt conveyor in many ways. The different aspect is that the value of running resistance coefficient is larger than that of traditional belt conveyor. The main resistance coefficient is choosed by the experience of designer and affects the power of conveyor conspicuously. The research on main resistance coefficient is helpful to calculating the power accurately and avoiding losing resource. Indentation resistance accounting for about 75% is the main part of main resistance. Thus, One-dimension model and Two-dimension model are set up by systematic research on the indentation resistance in this paper.Constitutive equation of One-dimension model is according to the stress and strain expression of generalized Maxwell model and stress relaxation function. The material properties of viscoelastic belt are determined by time and temperature principle and during the analysis, only the one-dimension stress and strain in vertical direction is considered and shear stress and incompressibility of the belt is unconsidered. By the counterpoise of load and stress, we can get geometric equation and equilibrium equation. By solving integral equation, we can get the formula of indentation resistance in the One-dimension model. Considering the normal stress and tangential stress and the compressibility of belt we can get geometric equation and constitutive equation of Two-dimension model by the roller rolling with the given constant speed over the belt. The equilibrium equation is set from the analysis of two-dimension stress and strain. State variables are expanded into a set of Fourier series with period boundary condition basing on working principle of belt conveyor and then we can get state equation. The analytical solution of the indentation resistance is set by nodes displacement and transferring matrix.By analysis of transmutation of pipe conveyor belt, bending model is set up and bending moment of any section is obtained, and then we can get the press on the roller given by the bending belt.The indentation resistance is calculated by the theory of One-dimension model and Two-dimension model based on the system parameter. The parameter which influences the indentation resistance is capacity, thickness of belt, and diameter of roller by the analysis and comparison. The method of modifying the main resistance coefficient is developed combining with the design method of CEMA.