Applications · Water Treatment

STATIC MIXER FOR COAGULANT FLASH MIXING

Flash mixing of aluminium sulphate, ferric chloride, or ferric sulphate into raw water requires extremely rapid mixing within the first fraction of a second of contact. The Velocity Gradient (G-value) (velocity gradient) governs destabilisation efficiency.

Turbulent | High G-Value | Sub-second Mixing
← Back to Applications
G = 300–1000 s¹
Key Parameter 1
<1 s Contact Time
Key Parameter 2
Coefficient of Variation (CoV) ≤0.05
Key Parameter 3
DN100–DN1200
Key Parameter 4
Process Scheme
Raw Water
Flow Meter
Coagulant Dosing
VN Mixer
Flocculation Basin
Sedimentation

Mixing Criteria

Velocity Gradient (G-value) (velocity gradient) 300–1000 s¹ at mixing zone. Contact time <1 second for effective particle destabilisation. Coefficient of Variation (CoV) ≤0.05 across pipe cross-section before flocculation zone. Mixer must maintain Velocity Gradient (G-value) across flow turndown range. KE preferred for flash mixing (higher K-factor generates greater Velocity Gradient (G-value), essential for particle destabilisation). VN applicable only on large-bore low-velocity mains where ΔP budget is very tight.

Typical Viscosity
0.8–2 cP (centipoise) (raw water with coagulant)
Reynolds Number (Re)
Reynolds Number (Re) 10,000–500,000 (turbulent)

Material & Special Requirements

Preferred MOC: FRP or 316SS for alum (Al₂(SO₄)₃). FRP or rubber-lined for ferric chloride. Carbon steel not suitable for acidic coagulants.

VN preferred — generates higher Velocity Gradient (G-value) at lower pressure drop (ΔP) than helical. Injection nozzle at centreline in highest-turbulence zone. Immediately upstream of flocculation basin (no settling between mixer and basin).

Recommended Mixer
KE Series — Helical Element
Kenics-equivalent. 180° RH/LH helical elements joined at 90°. Halves striation thickness per element. Works laminar to turbulent. Best general-purpose choice.
Build Model Code → Request Application Quote →