7 Bucket elevators Capacity calculation Force calculation Mass / meter Sum. resistant coeff.Mat. flowSpeed
8 Screw conveyorsTransported materials: material not sensitive to the crunching effect of the screw (ashes, chemicals, fertilizers, food products, meal, ores, paper pulp, salt, sand...)Screw types
9 Screw conveyorsFlow direction typesMaterial in the trough
10 Screw conveyors Construction Parts: 1 Trough 2 Screw 3 End bearing Section A-AParts:1 Trough2 Screw3 End bearing4 Head bearing5 Hanging bearing6 Drive motor7 Coupling8 Gear10 Feed opening11 Discharge openingPushed or pulled screw?
11 Screw conveyors Required power of a horizontal screw: Capacity of a horizontal screw:P = ρhIv(Lf±H) in Wρh= Bulk densityIv= Volumetric capacityL= Horizontal distance of start and end pointsH= Height difference of start and end pointsf= General resistance factor (0,3 – 4,4)Capacity in m3/hDiameter of the screw in mScrew pitch in mSpeed of screw in 1/minFill factorφ=0, high-density, highly abrasive materialφ=0,25 high-density, lightly abrasive materialφ=0,32 low-density, lightly abrasive materialφ=0,4-0,5 low-density, non-abrasive materialk = factor for inclined screwinclinationFor ribbon screws:Max. allowed screw speed exists!k factor
12 Screw conveyors Vertical screws Minimal required speed of the screw At critical speedAbove critical speed
13 Roller conveyors Transported material: Type of roller elements: different unit loads, such as:boxespalettslong steel or wood materialcomponent assembliesType of roller elements:- Rollers- Wheels (skates)- BallsClassification of roller conveyors:- Gravity roller conveyors- Manual roller conveyors- Powered roller conveyors
14 Gravity and manual roller conveyors FixedExpandablevvlimitAccumulation of thetransported unit loadt