IMPROVEMENT OF STRUCTURAL AND DYNAMIC PROPERTIES OF THE HEARTH PLATE OF AN ELECTRIC ROASTING FURNACE FOR BULK MATERIALS

In this work, we consider the basic dynamical system of electric roasting furnaces, i.e., an oscillating movable hearth plate for vibration displacement of bulk particles. The main disadvantage of oscillating dynamical systems consists in fluctuations in the oscillation amplitude due to its sensitivity to minor changes in the excitation and natural frequency, as well as to external factors. We report experimental data on the duration and velocity of movement of loose material along the hearth plate surface on the example of expanded vermiculite, which ensure the highest quality of the obtained product and the highest productivity of the roasting process. The data obtained formed the basis for improving the design and dynamic properties of the hearth plate and establishing a mode of vibration acceleration of the plate at a constant range of oscillations with zero sensitivity of the amplitude to changes in excitation frequency and other aforementioned factors. The vibration amplitude remains constant, ensuring a stable and stationary mode of vibration displacement of bulk material and maintaining the possibility of motion control. The proposed technical solution eliminates the extra degree of freedom of the hearth plate and, as a consequence, its oscillating mode, simplifies and improves the furnace design, preserves the previously established modes of vibration displacement, and reduces the dynamic sensitivity of the hearth plate to zero. The distinguishing feature of the proposed design of the hearth plate consists in its operation in the frequency range from zero to its free oscillation.