Design Of The Industrial Prototype Of A Screw Press Device And Evaluation Of Its Technical Parameters

This study presents the theoretical and experimental results obtained in the design of an industrial prototype of a variable-pitch screw press developed for coal briquette production. The design process considered the following operational parameters: screw compression force — 2.5 kN, nozzle diameter — 25 mm, working chamber diameter — 100 mm, and a five-step screw with a maximum pitch of 80 mm decreasing by 5 mm per step, operating at a rotational speed of 1.5 rev/s. For a feed material density of 1346 kg/m³ and a press capacity of 2500 kg/h, the total electric motor power, gearbox transmission ratio, and overall press dimensions were determined. The implementation of the proposed design and method demonstrated a twofold reduction in briquetting costs, thereby enhancing overall economic efficiency. Industrial trials confirmed that the developed screw press fully satisfies the technical requirements for industrial application of this class of machines. The calorific value of the produced briquetted fuel ranged from 750 to 800 °C, while introducing a raw material mixing process at 95 °C was found to reduce emissions of sulphur oxide (SO₂) by 1.8 times, magnesium oxide (MgO) by 1.23 times, and anhydrous sodium carbonate (Na₂CO₃) by 1.36 times relative to the permissible exposure limit (PEL).