Theoretical conveying capacity of screw conveyors

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The theoretical slag discharge capacity of a screw conveyor can be calculated using the following formula: Q=π4×D2-d2×P-t×n×60, with a volumetric efficiency of η=100%. During the tunneling process, the actual maximum amount of material removed can be calculated using the following formula: (assuming maximum tunneling speed) Q1 = π/4 × Ds² × ν × 60. In the formula: D – the inner diameter of the screw conveyor ； Diameter of the central shaft of the screw conveyor ； p- pitch ； t- Thickness of the screw blades in the screw conveyor ； The maximum rotation speed of the n-screw conveyor, the excavation diameter of the shield machine, and the maximum advancement speed of the shield machine. The calculation parameters provided for this shield machine are: D=0.8m ； d=276mm ； P=640mm ； t=40mm ； n=16rpm, 6.3m, 0.08m/min. Calculation results: The theoretical conveying capacity of the screw conveyor is Q=280 m3/h (η=100%). The theoretical waste discharge rate of the tunneling machine at its maximum digging speed is: Q1(100%)=150 m3/h and Q1(130%)=195 m3/h; thus, the safety factor is 1.43.