INVESTIGATION OF THE BULK MATERIAL MOVEMENT KINEMATICS IN CONICAL SCREW CONVEYOR

New design of the conic shape screw conveyor is presented in the paper and the results of theoretical investigations of the bulk material kinematic movement in this conveyor were shown. Dependencies for finding kinematic and operating parameters, which provide long-term stability of such mixers were found. Stand equipment for investigation of the transporting efficiency and mixing of the bulk materials have been developed and manufactured. Mechanic screw conveyors’ properties at high frequency range of rotation, under smooth and sharp starting, rotation frequency change and reversing in the automatic regime have been studied taking advantage of the ALTIVAR 71 and multipurpose measuring system with accelerometers for finding dynamic loadings by PC. The results of experimental investigations of the efficiency depending on the screw pitch and every next turn, the screw conic surface inclination and the screw rotation frequency are presented. It will make possible to clear the process of the bulk materials transporting and mixing for every possible combination of the initial parameters. Specifically, increasing the increment of the cargo displacement radius per turn from 1 mm to 5 mm results in a velocity increase ranging from 1.28 times to 2.44 times. Moreover, increasing the inclination angle of the forming cone surface from 1 degree to 2 degrees provides a 1.18-fold increase in productivity, and varying the increment of the screw pitch from 0.004 m to 0.01 m per turn results in a 1.07-fold decrease in productivity. Increasing the rotation frequency of the conical screw α from 200 r/min to 500 r/min leads to a doubling of productivity.