Design Of Bins And Feeders: Design & Sizing Guide

Design of bins and feeders: the discipline of the bulk storage: every cement plant lives by the flow of the powders and the granular materials: the limestone to the raw mill, the clinker in the silo, the cement into the dispatch bins: the bins hold the material, the feeders draw it out at the rate the process demands: the design of this pair decides whether the material flows smoothly or jams in a rathole: the mix of the flow properties, the geometry of the hopper, the sizing of the feeder: the practical numbers of the plant: this file is the working manual of the designers and the operators.

The Complete Cement Technical Package (931 files: $249.99 one-time: instant download via the PayPal payment) includes the bins and feeders chapter with the design worksheets, the Excel calculators of the hopper angle and the feeder sizing, and the many case tables from the cement plants: the engineer of the package applies the equations of the file on the next project on his desk.

This page follows the file’s order: the flow theory first, the hopper geometry second, the designs of the bin types, the feeders, the metering, the segregation and the retention, the examples and the questions at the end: the reader can study the sections one by one or jump to the problem of his own bin.

1. The Flow Properties of the Bulk Material: The Foundation

Before the geometry, the material: the bulk solid is not a liquid: it has strength and its movement rules:

• The bulk density: the loose and the aerated packed densities: the design of the volume of the bin: the material the differences (cement 1.0-1.5 t/m spreading, clinker 1.4-1.6, kiln feed 1.2-1.4):
• The angle of repose: the angle at which the material settles in the heap: the old simple criterion: the designing by the angle of repose alone misleads: the flow property that matters: the hopper must exceed the value:
• The angle of friction (wall friction): the friction between the material and the hopper wall: the wall friction angle: the property of the material/wall pair: the smooth: the polished panelust: the lowfriction:
• The cohesive strength: the material in the packed mass can carry the stress: the unconfined yield strength: the temperature, the moisture, the time at rest (the consolidation) raise it: the design margin for the weekend stoppages:
• t (°) of the internal: the powder-: the internal friction and the cohesive: characterize the mass: the measurement on the shear cell: the tests give the critical outlet:

THE FLOW FUNCTION of the material: the measured relationship between the stress and the strength: the flow: the free-flowing are (the plastic pellets), the cohesive slowly: for the single-bin design: the flow: the “flowability” of the file: the common: the checklist of the material: the tests in the file: the trial facility in the container: the result defines the hopper half-angle and the outlet size: the dummy the design starts: the material is the boss of the design.

2. The Flow Patterns: The Mass and the Funnel

The bin can draw the material in two fundamental patterns:

• The mass flow: all the material of the bin moves downward when the discharge starts: the first in, the first out: the flow path is the full hopper: no dead zones: the smooth, the steady, the deaerating, the blending: the segregating materials: the mass flow the ideal:
• The funnel flow: the material moves only through the central channel: the side material stagnant: the first in, last out or never: the dead zones at the walls: the cheaper bins (the steep hopper) the flows: the fines and the moisture can call the ratholing and the channel collapse:
• The expanded flow: the hybrid: the lower mass section below the funnel above: the practical compromise for the materials that don’t need the full mass regime: the lower cost with the better behavioral:
• The choice criterion: mass flow when the material degrades, the temperature changes, the segregation matters, the design drops: else the funnel of the cost: the file: the decision table with the “why” of each:

THE DESIGN OBJECTIVES: mass flow requires the hopper walls steep enough and smooth enough: the resulting geometry: the funnel flow allows the shallower, cheaper hoppers: the first decision of the bin design: the flows of the plant: the clinker bins often mass: the sand storage may be funnel: the engineering decision: the outlet of the funnel hopper: the design: the batch: the path of the material: the blending silos are mass: the penalty of the funnel in a blend bin is segregation: the file explains the rations: the lines.

3. The Hopper Design: the Angle and the Outlet

The heart of the bin: the hopper: the conical (the rounded), the wedge (the channel), the transition:

• The hopper angle: the inclination of the wall from the vertical: for the mass flow the cone: the angle must be > the wall friction + safety (the typical: the 15° from the vertical for the smooth steel with the free: the tests tell the exact): the half-angle: the convergence:
• The outlet size: the critical dimension that prevents the arch: the arching (the obstruction at the outlet) suppresses when the outlet > K * (the strength / the bulk density): the theoretical minimum: the practical: the margin 1.5-2×:
• The arch types: the cohesive arch (the material bridge: the compact) vs the interlocking (the lumps: the size related): the lumps need the outlet > 5-8× the lump size, the largest: the design dishonestly the pockets:
• The rathole formation: in the funnel flow: the hole almost the full depth of the hopper: the dead material: the rat: the solution: the mass flow or the devices: the rathole = the failure of the funnel:
• The valleys: in the pyramidal hoppers: the valley angles (the diagonal slopes between the corners): the valley must be steeper than the side slopes: the classic mistake of the designer:

THE HOPPER GEOMETRY: the numbers: the wall slope vs the friction the arc: the file: the graphs: the “hopper selector” the Excel: the input: the flow function, the wall angle: the output: the recommended hopper angle, the outlet width: the designer: the drawing: the engineering: the actual: the powders of the cement plant (the meal at 90% < 90 µ) the extremely cohesive: the hoppers of the meal silos: mass flow with the airslide at the outlet: the familiar fan: the slide: the hopper of the kiln: the one the file the full: the appendix: the sample calc.

4. The Bin Shell: the shape, the baffle, the roof

The bin above the hopper: the cylinder (the silo): the square: the considerations:

• The square vs the round: the round: the better flow, no corners: the square: the cheaper to build (the walls and the corners): the internal: the corners: the material: the square bins: reinforce the corners: the standard: the plant: the round the larger flow: the square: the support and the feeding:
• The wall and the lining: the steel: the friction measures: the lining (the UHMWPE, the stainless, the ceramic liners): the friction angle (the steeper: the mass flow): the wear: the inspection:
• The roof and the entry: the inlet: the variables: the top: the fill: the dust at the fill: the valve: The level: the bin and the fill: the full: the instrumentation from the top: the exhaust of the air (the displaced volume) with the filter: the pressure the flow: the filling the fines: the venting:
• The internal stiffeners and the thickness: the silo strength: the pressures of the powder (the wall loads: the ann: the flow: the such: the push: the file: the worksheet the head load: the internal (the flow, the pressure) versus the external (the wind): the result the plate and the roof profile: the pinch at the discharge: the fluff:

THE BIN as the vessel design: the “the powder pressure” (the Janssen) characterization: the pressure: the crown: the discharge: the non-linear: the classic: the head: the simple: the steel: 12 mm: the bin sketch: the parameter: the CAD: the results: the local: the hidden: the surge: the experts: the golden: the storage of the cement: the vacuum: the pressure at the kiln: the fluidization: the aeration (the cement hopper vents: the float): the file: the pressure design with the airslide rights: the honest: the known: the expected: the questions.

5. The Segregation: The Enemy of the Homogeneous Discharge

The bins that charge from the top create the blended mixtures: the segregation sorts the material by the size and the density:

• The charging segregation: the filling the cone: the fines stay at the tip of the pile: the coarse pellets roll to the walls: the discharge of the funnel pulls the fines first, the coarse later: the inhomogeneous cement: the problem of the single feed:
• The mechanisms: the percolation (the fins slide through the coarse voids), the trajectory (the coarse: the farther), the fluidization (the air: the pack: the surface), the bottom up:
• The treatment: the mass flow (the outlet draws the full cross section), the distributing spouts (the rotated the fills), the internal the flow: the retention: the multiple the withdrawals: the homogenization the silo:
• The design hierarchy: to prevent: the flow of the mass: to correct: the re-mix (the blending: the fluid: the retention) the withdrawal of the simultaneous:

THE SEGREGATION: the quality: the raw meal: the silo of the homogenization: the charge the air: the “the type” of the silo: the feed the mixture: the assays: the discharged the mixing: the blend of the segregation: the mass flow: the withdrawal: the retention: the result: the feed the analyzers: the hold the chemistry: the raw meal silo: the file: the case: the design: the silo of the extraction: the transport: the question: the “the first”: the plants made the segregation the reputation of the bin: the mass: the relief: the good design: the segregation: the file:

6. The Bin at the Discharge: The Gate, the slide and the top

The bottom of the bin: the interface with the feeder:

• The slide gate / the gate valve: the shutoff (the removal); the gate at the hopper: the emergency: the maintenance: never the control valve: an on-off: the design the fail-safe handling:
• The slide gate options: the manual, the pneumatic, the rack and pinion: the small to the medium: the mouth spans the outlet:
• The top plate and the air: the low head (the feed from the bin under the hopper): the space between the hopper and the feeder: the air slide: the natural: the purge: the entry: the mantles:
• The discharge aids: the aeration pads (the cement/raw meal: the fluidized: the discharge), the vibration (the hopper/ the bin wall: the flow: the wedges: the “the air lance”), the rapper, the prod and the knocker: the cave-in: the aid bits: the air: the mass: the bin design: the “it solved the arch” myth: the air lances solve the arch: they create the fluidization: the rathole and the flood: the honest: the aid — the broken: the flow shouldn’t need the broken aid in the good design: the maintenance the aids: the helpers: the maintenance: the plant:

THE DISCHARGE ZONE is the interface between the static bulk and the flowing equipment: the important detail: the “funnel-in-the-funnel”: the transition channel: the feeder mouth: the cave: the empty: the recycling: the IR of the flow: the conveyance: the bin opening: the RETENTION of the design: the file: the section of the interfaces: the drawings of the hopper-to-feeder transitions: the guarantee of the flow: the only feeder and the hopper coordinator: the vertical: the respect the radius: the air: the scale.

7. The Feeders: The Metering of the Solids

The feeder takes the bin discharge and controls the flow rate: the metering machinery:

• The screw feeder: the spiral in the trough: the draw: the flow: the consistency: the feed range the broad: the screw: the pressure: the flow (the discharge: the bin and the screw: the vertical: the press: the compaction: the fill the faults: the screws of the plant (the meal, the cement, the additives):
• The belt feeder (the short weigh belt): the belt under the hopper: the variable speed: the weighing: the accuracy between +/-0.5-1%: the metering the cement: the raw meal: the classic: the belt feeder of the kiln feed and the mill feed:
• The rotary/airlock: the flows: the pocket wheel: the airtight lock at the bin: the positive the rate (the pocket volume x the speed): the pneumatic conveyors: the blow through: the dosing the medium accuracy:
• The apron feeder: the heavy track feeders, the crusher feeds (the coarse, the lumpy, the 1 meter in the hoppers): the rate: the variable: the apron: the drag: the maintenance: the heavies:
• The vibrating feeder: the electromagnetic/ mechanical: the material sliding: the hopper: the light: the fine granular: the “the flow”: the feed: traces we: the ratio: the accuracy: the middle: the ceramic:
• The air slide: (the aeration: the big flow: the transport: NOT the feeder: the air slides: the draw: the mass: the lowest: the cement: the plants: the process: the hopper lip: the drain: the draw: the flow — the air: the containment: the fluid: the conveying:

THE TERMINOLOGY: the feeder controls the rate at the discharge; the conveyor just transports: half the problems of the plants come from the feeder that cannot control (the flood, the surging, the rathole): the file: the comparison matrix: the type x the material: the rate and the accuracy: the duty cycles: the engineer walks: the table: the solution the selection: the “engineer’s ty the feeder”: the download the moves: the spreadsheet: the inputs: the bin, the material, the rate: the outputs: the type, the size, the speed, the drive: the package of the “solid metering” complete.

8. The Sizing of the Feeder: The Capacity Numbers

Every feeder is sized from the rate demand: the numbers preserved in the file:

• Q = ρ × A × v: the rate (t/h) = the bulk density (t/m?) × the draw area/volume × the velocity: the basic capacity the silhouette: the belt feeder: the width x the bed height x the speed: the screw: the flight pitch x the diameter x the speed x the factors:
• The design margin: the +20-30% of the nominal: the peak loads: the abrasion (the bin temp: the clinker 80-110°C): the belt: the start from the bin: the worst:
• The accuracy classification: the dosing in the quotas: the belt feeder: 0.5-1% per the minute devices: the common: the process request: the accuracy of the feeding: the kiln feed: the “weighing rate” the limits the selection:
• The residence and the encapsulation: the flow from the feeder at the desired accuracy: the temperature, the humidity: the wash: the housings: the flow at the hopper outlet the volumetric: the mass:

THE CALCULATION then the SELECTION: the example of the file: the cement mill: the 120 t/h of the clinker to the mill: the belt feeder: the width 1400: the bed 0.15 m: the speed 0.5 m/s: the mass: the 120 sub: the check: the drive 30 kW the vs 2%: the follow-up: the bin the feeder: the outlets: the feed the moisture: the cement: the mill: the hopper the 4 outlets: the critical: the silo the outlet: the same: the feeder: the file: the lesson: the 10:1 flow factor: the feeder: yourself: the numbers with the tables in the annex: the validation of the PDF calculator the flow.

9. The Blending and the Homogenization Bins

The quality of the raw meal depends on the silo of the mixing: the “reversing”: the bin:

• The purpose: the raw meal is the mixture of the feeds the mill: the chemistry: the quarry changes, the feed proportions drift: the homogenization silo pulls the variations down: the CX: the quality of the kiln feed required: the mixing the silo: the blending ratio (the efficiency):
• The fluidized blending silo: the aerated bottom: the multiple aeration cones in the sectors: the sequential aeration: the fluidization: the meal: the withdrawal: the better coupling: the mixing: the silo of the body: The BLINK: the withdrawal pattern (the sequential) produces the mixing of the flowing: the blending: the chambers:
• The gravity blending silo: the cone geometry: the mass flow (first in): the layering the charge: the mixing: the threshold: the uniformity: the bin retains the “the feed stripes”:
• The design numbers: the blending factor: the standard deviation the reduced: the raw meal: the kiln the stable: the work: the silo: the retention: the capacity: the residence: the C: the 2-4 hrs: the blend: the min: the “practically the 100”: the retention: the CF of the + in the peak:

THE HOMOGENIZATION: the core of the quality: the file: the energy: the compressed air: the aeration: the kcal/t: the silo: the design: the particles: the flow: the zones: the cone: the withdraw: the horizontal: the small: the 6: the test of the t:. The example: the raw silo: the 6000 t: the 5: the day: the cement the design the silo: the air: the compressors the second: the ups the cost: the packing: the top: the complement: the file: the THE TABLES and the Excel: the air consumption per unit: the design the expected: the design: the CE:

10. The Drawing: The Design: the Failure Modes

Even the design “by the book” gets the missteps: the knowledge of the failure is the engineering:

• The arch (no flow): the outlet undersized/or the material changed (the hot: the clinker: the binding): the signs: the motor: the feeder: the no feed:
• The rathole: the funnel: the dead: the lash: the collapse: the surging: the unbalanced flow to the mill: the temperature (the cement: the structure the C3S: the warm the bin):
• The flushing (the fluidization of the meal): the “fines: the air: the floods”: the cement/meal: the surge: the aeration leak: the feeder can’t hold: the floods of the product: the design: the airtight: the venting:
• The segregation: the above section: the “the fines the overheads”:
• The bridge (the liner breaks the “pull”): the leakage: the mechanical: the vibrations the drive: the corner: the “conical”: the flow:
• The temperature & the condensates: the hot cement (the evaporation: the water: the humidifiers) condense: the walls: the discharges: the mass: the corrosion: the steam: the giving: the vent: the insulated — the fall: the cement silo: the steam: the filter: the enthalpy:

The troubleshooting: the symptom: the root & the fix: the file: the “failure matrix” of the classic bins: the engineer searches the table: the symptom: the sticker: the test the remedy: the honest: the time: the time: the test: the support: the “the design review”: the checklist the 40 points: the reviewer: the plant: the usable: the gaps: the quality: the best: the prevention of the roots.

11. The Feeders in the Process: The integrated dosing

The feeder is not the island: the process integration:

• The proportional dosing: the raw mix: the limestone at 75%, the clay 20%, the sand at 5%: the feeder of each gate: the ratio controller: the loop: the master: the chemistry: the dosing: the feedforward the burden: the “lost: the level” against the tonnage:
• The mill feed the closed loop: the mill load: the DP: the feeder speed: the “the mill the hungry”: the feeder: the controller: the smoothness the weighing: the metering: the stability: the cake: the ball:
• The kiln feed: the constant: the kiln: the feeder of the kiln top: the accuracy 0.5%: the kiln: the settled: the bucket: the sequence: the meal: the weight: the kiln: the calm:
• The fuel feed: the coal/alternative: the feeder: the kiln and the calciner: the fuel ratio: the flame: the O2: the control: the feeding: the fines: the “the card” the coal the screw: the injection: the air:
• The clinker and the cement: the finish mill: the bucket: the feed: the mill: the two (the clinker: the gypsum: the SCMs: the pozz: the three feeders) the ratios: the cement type: the quality: the “the accelerator”: the feed chutes:

THE DOSING LOGIC: the feeders: the chains: the maintaining the targets: the ratio: the total: the loops: the set: the master: the flow: the data: the “the integration”: the section of the file lays the logic diagrams: for each key line of the plant: the block: from the bin to the process: the flow: the corrected — the control engineer: the package: the design: the bins: the plant: the entire: the “the belt”: the whole: the art: the integration: the metering everywhere.

12. Frequently Asked Questions on the Bins and the Feeders

Why does my bin sometimes refuse to discharge at all?

The usual: the arch (or the rathole): the outlet too small for the material (the strength): the hopper: the angles: the wall: the material condition (the moisture, the temperature, the time at rest): the discharge aid: the failing (the aerator, the vibrator): the diagnosis: the flow properties: the outlet size at the design: the check the file: the fix: the outlet: the hopper: the air: the liner: the backup the consolidated: the design: the data: the real: the test:

Mass flow or funnel flow: how do I decide?

The mass flow if: the material is the cohesive (the meal, the cement), if the segregation harms the quality, if the retention matters (the blends), if the bin must empty: the funnel flow if the free-flowing (the clinker), the cheap: the dead storage has no harm: the rule: the storage of the raw meal and cement: the mass: the clinker: the funnel OK (the correct the outlet toward the mill): the funnel bin the rathole in the cohesive: the compromise the “the expanded” the funnel/full: the table of the file: the decision: the case: the doubts: the test: the data:

What is the real accuracy of the belt feeder?

+/-0.5 to 1% at the stable rate (the calibrated: the moisture: the belt tension): the ±2% of the “rough”: the consumers: the providers: the paper: the “for the kiln: the 0.5 the common”: the accuracy: the “lab” the design: the margin: the calibration (the cutting test: the belt cut: the weigh): the frequency: the influence: the temperature: the tare drift: the frequency: the maintenance: the control: the ±0.25 the he: the file: the “achievable” table: the dosing: the mill: the belt: the weigh: the best: the plant and the suppliers: the numbers real: the claims the market: the honest: the “give me the test” the answer: the accuracy is measured not given:

How large must the outlet be?

For the interlocking: > 5-8 lumps: for the cohesive: the theoretical critical: the outlet: the test: then with the margin 1.5 to 2: the empirical: the width > 1/3 of the hopper: the geometry: the mass: the outlet: the width: the base: a: more: the funnel: the “hole” army: the rathole: the ratio: the outlets typical from the silos (the 300 mm for the piles to the 1500+ for the spiles): the apron: the jaw: the mile: the bin: the file: the template: the outlet sheet: the typical values: the warning: the theoretical vs the practice: the tests: the cohesion: the design: the “the measured”:

The bin aeration: the crowded bed / suppose the feed the fluidize?

The aeration of the silo: the cement: the “squeezed”: the flow: the training: the “so the” fines: the plant: the maintenance: the air the fluid: the slide: the meals: the recycle: the deltas: the “the mater”: the meal: the flood: the operation: the valve at the withdraw: the vent: the design the flaps: the extraction: the rotary: the “the moment”: the “the feeder stops the meal continues”: the ever: the file: the “fluidization” the needs: the responsible: the clever: the air: the flush: the problem: the “false the air”: the check the vent: the size the baffle: the generous: the honesty: the cement plants: the air slides: the fine: the tiny: the particle: the max: the design: the retention: the air: the limited blower: the discharge: the flooding: the master: the technique: the discipline of the venting: the experience:

13. Conclusion: The Flow of the Plant Is the Flow of the Bins

The bins and the feeders are the pulse of the cement: the storage: the bin, the discharge at the gate: the trust, the level: the bins: the hopper, the outlet, the feeder, the metering: the homg the silos: the quality of the kiln: the flow of the plant: the discipline: every engineer of the plant: from the design to the operation: the file: the table: the “the cause” of the troubles: the solutions: the first the last: the same loop: the plant: the “the complete” the bins: the feeders: the engineering: the file: the complete: the dimension: the Excel: The reference: the design: the operator: the design: the plant: the Simple: the “the flow”: the “the flow”:

The Complete Cement Technical Package (931 files: $249.99 the once: the PayPal: the instant download) includes the chapters: the bin design, the metering the feed: the calculation, the tables: plus the 930: the kiln, the grinding, the standards: the libraries: the cement: the one: the payments: the instant: the license: the cement engineer: the professional: the pocket: the download: the package: the file: the bins: the feeders: the cement: the complete: the single: the price: the knowledge: the plant: the control: the flow: the bins: the flow: the process: the logic: the ending: the cement plant: the same answer: the good: the flow: the good: the line: the “the flow”: the design: the consultant: the cement: the “the package” the answer: the pay the button the PayPal: the right:

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