Designing mining machinery screw modules

Abstract

Screw modules are widely used in technological and transporting machines. Their main disadvantage is low productivity due to the fact that the material moves partly in the direction of the feed and partly rotationally as a result of the torque transmitted by the screw blade to the material. The rotational component of the material movement significantly reduces the performance of the screw. The work considers the possibility of mining machines with screw modules efficiency improving by determining the rational screw shaft configuration, depending on the properties of the feed material and the operating conditions of the module, realized at the designing stage. The aim is achieved by means of a mathematical description of the screw feed process that takes into account processes occurring both on the surfaces of the material contacts with the working bodies of the machine and inside the material mass, including the occurrence of a sliding surface in the material. Furthermore, some part of the material sticks to the screw and moves in concentric circles, with no axial movement in the feed direction, which reduces the performance of the screw. The screw shaft configuration is determined by means of design procedures based on the mathematical description of the screw feeding process, given in the work. The description takes into account the processes occurring in the mass of the feed material. The resulting mathematical model of the screw feeding process allows designing screw shafts with shape identical to the sliding surface in the material, which will increase the performance of the screw module by 20-23%, by reducing the rotational component of the material movement and increasing the translational component in the feed direction.