A chain scraper conveyor moves bulk material through a trough using flights attached to an endless chain. The working run pushes the material toward discharge while the empty flights return along the other side of the loop.
Chain Scraper Conveyor Interactive Calculator
Adjust trough area, chain speed, bulk density and filled fraction. Follow the attached flights around the chain loop and compare volume flow with mass throughput.
Equation Used
- Steady filled cross-section moving at chain speed.
- No slip, recirculation, spillage or inlet starvation is calculated.
- Density is bulk density, including the voids within the bulk material.
- Unfilled percentage describes unused trough area, not particle porosity.
- Drive power, chain tension and component ratings are outside this capacity estimate.
Cutaway teaching schematic with a continuous chain, attached scraper flights and empty return. Guide wheels, chain pitch and clearances are illustrative. Capacity assumes steady bulk motion at chain speed. The cross-section inset assumes a square solely to visualize entered area and fill; it is not a fabrication drawing.
Flights push material through a trough
The chain carries scraper flights along the working run. The flights push the bulk toward discharge; after material leaves, they travel around the end guide and return empty.
Hiscox figure 1225 shows a chain supported by rollers on axles carrying trough-fitting scrapers. The cutaway animation uses that attachment principle and exposes the lower working run, upper return and floor discharge. The end wheels show the chain route, not a detailed tooth-contact model.
Bulk-material conveying
Scraper conveyors use an enclosed or open trough to contain material while chain-mounted flights move it. The appropriate chain, flight, liner and housing depend on the material and duty.
This calculator estimates throughput from a supplied cross-section, filled fraction, speed and bulk density. It does not select a conveyor, certify temperature limits or predict wear life.
Capacity from filled cross-section
Filled cross-sectional area is Ak. If the bulk advances at speed v, volumetric flow is Avk m³/s, or 3600 Avk m³/h. Multiplying by bulk density ρ in t/m³ gives tonnes per hour.
Each of area, speed, density and filled fraction has a linear effect on mass throughput in this model. Density has no effect on volume flow. The unused cross-section is 100(1−k)% and must not be confused with voids between particles, which are already included in bulk density.
The drawing uses illustrative wheel and flight dimensions. Its separate cross-section inset uses a square because area alone does not specify both trough width and depth.
Default capacity estimate
With area 0.25 m² and filled fraction 0.75, the working material area is 0.1875 m². At 0.8 m/s, flow is 0.15 m³/s or 540 m³/h.
For bulk density 0.85 t/m³, this corresponds to 459 t/h or 127.5 kg/s. Raising only density to 1.70 t/m³ doubles mass throughput to 918 t/h while volume flow remains 540 m³/h. These are model estimates, not measured equipment ratings.
What a throughput estimate cannot establish
Feed availability, slip, inclination and material behavior can change achieved flow. The calculator represents the operating fill as an input; it does not predict those effects.
A drive and chain selection also requires resistance, conveyor geometry, component ratings and starting conditions. None can be inferred from capacity alone.
Calculator questions
Why does density leave the animation speed unchanged?
Density converts volume to mass. Chain speed is a separate input and determines the rate of visible travel.
Is the trough square?
Only the explanatory inset assumes a square. Entered cross-sectional area could describe other trough shapes; width and depth are not specified.
Does unfilled mean the air between grains?
No. It means unused trough cross-sectional area. Bulk density already accounts for the spaces within the material.
Does this size the motor?
No. It calculates capacity, not drive power or chain tension.
References & Further Reading
- Gardner D. Hiscox, Mechanical Movements, Powers, Devices and Appliances (1901), printed page 303, figure 1225: roller-supported chain with attached trough scrapers.
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