The capacity of a vibrating screen depends on several factors, including screen dimensions, material characteristics, operating conditions, and efficiency. Here’s a step-by-step method to calculate the theoretical capacity of a vibrating screen:
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1. Basic Formula for Capacity (Q)
The general formula for calculating the capacity of a vibrating screen is:
\[
Q = A \times V \times \rho \times K \times S \times D \times C
\]
Where:
– Q = Capacity (tons/hour)
– A = Effective screening area (m² or ft²)
– V = Material velocity (m/min or ft/min)
– ρ = Bulk density of material (tons/m³ or tons/ft³)
– K = Correction factor for moisture & particle shape
– S = Open area percentage of the screen deck (%)
– D = Depth of material bed (m or ft)
– C = Efficiency factor (depends on screen type and vibration)
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2. Key Parameters
# (a) Effective Screening Area (A)
\[
A = \text{Width} \times \text{Length} \times (\text{Open Area \%})
\]
– Width & length are the dimensions of the screen deck.
– Open area depends on the wire mesh or perforation size.
# (b) Material Velocity (V)
For inclined screens:
\[
V = 0.5 \, \text{to} \, 0.8 \, .jpg)
xt{m/s} \, (\text{varies with inclination and vibration intensity})
\]
# (c) Bulk Density (ρ)
Depends on the material being screened (e.g., sand ≈ 1.6 t/m³, gravel ≈ 1.8 t/m³).
# (d) Correction Factors
– K: Adjusts for wet/dry screening and particle shape (~0.4–1.2).
– C: Efficiency factor (~0.7–0.9 for most industrial screens).
# (e) Bed Depth (D)
Optimal bed depth is typically ≤ 4× the aperture size.
—
3. Simplified Empirical Formula
For quick estimation:
\[
Q = F \times A \times C
\]
Where:
– F = Feed rate per unit area (~10–30 t/h/m², depending on material).
Example: