Cyclone Separator Calculator

Determine aerodynamic cut-point particle diameter (d50 in microns), overall collection efficiency, inlet velocity, and static pressure drop for cyclone pre-cleaners.

Exhaust Airflow (ACFM)

Barrel Diameter (D_c in)

Particle Density (g/cm³)

Cyclone Proportions

Gas Temperature (°F)

Median Dust Size (μm)

Aerodynamic Cut Point (d50)

5.8 μm

Overall Collection Efficiency: 94.2%

Pressure Drop (ΔP)

4.35" w.g.

Cyclone resistance

Inlet Gas Velocity

3,733 FPM

Target 3,000 - 4,000 FPM

Effective Spiral Turns (N_e): 5.0 turns in outer vortex

Inlet Duct Dimensions: 9.0" W × 18.0" H

Pre-cleaner Primary Role: Excellent Baghouse Spark/Spike Trap

Inlet velocity is within optimal centrifugal separation range (3,000 - 4,000 FPM).

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Cyclone Centrifugal Dust Separation & The Lapple D50 Cut-Point

Reverse-flow cyclone separators use centrifugal force to separate particulate matter from moving airstreams without moving parts or replaceable filter media. Gas enters tangentially at high velocity, spirals down an outer helical vortex toward the cone apex where heavier particles fling against the wall and drop into a dustbin, while clean air spirals up an inner vortex to the clean outlet.

Lapple Model Mathematical Formulation

Aerodynamic Cut-Point Diameter (d_50):
The particle size collected with exactly 50% efficiency:
d_50 = sqrt[ (9 × μ × W) / (2 × π × N_e × V_i × (ρ_p - ρ_g)) ]
Where W is inlet width, N_e is number of spiral turns (~5.0), and V_i is inlet velocity.
Fractional Collection Efficiency (η_i):
η_i = 1 / [ 1 + (d_50 / d_p)² ]
Cyclone Pressure Drop:
ΔP (inches w.g.) = 0.00296 × ρ_g × (V_i)² × K_H
Where standard Lapple geometry has an inlet head factor K_H ≈ 8.0.

Frequently Asked Questions

What is the d50 cut-point of a cyclone separator?

The d50 cut-point is the aerodynamic particle diameter that the cyclone collects with exactly 50% efficiency. Particles larger than d50 are collected with much higher efficiency (>90%).

Why are cyclones frequently installed upstream of baghouse filters?

Cyclones act as heavy-particle and spark pre-cleaners, capturing 80-95% of large abrasive dust before it reaches the baghouse, extending filter bag lifespan and preventing baghouse fires.

What is the ideal inlet velocity for an industrial cyclone?

The standard recommended inlet velocity is between 3,000 and 4,000 FPM (15 to 20 m/s). Lower speeds reduce centrifugal force, while higher speeds increase pressure drop and wall wear.