A wiped film evaporator uses rotating wiper blades (200–600 RPM) to spread feed as a thin turbulent film (0.1–0.5 mm) on the inner wall of a vertical heated cylinder — achieving residence times of 1–60 seconds at vacuum levels of 0.001–10 mbar. Processing 1–5,000 kg/h of heat-sensitive, viscous, or fouling-prone materials, it concentrates or purifies thermolabile actives inaccessible to conventional evaporators.
Feed enters the top of the heated jacketed cylinder; the rotor carries PTFE or graphite wiper blades that continuously spread, turbulate, and renew the liquid film on the heated wall. Vapour migrates inward to an integral or external condenser. The short residence time (1–60 s) prevents thermal degradation. Short-path distillation adds an internal coaxial condenser — vapour condenses within centimetres of evaporation, enabling molecular distillation at 0.001 mbar.
Challenges
Wiper Blade Wear on Abrasive or Crystallising Product
Abrasive particles erode wiper blade tips — increases film gap and reduces heat transfer.
Limited Throughput vs. Conventional Evaporators (<5,000 kg/h)
Small evaporation area per unit limits throughput — multiple units needed at scale.
Vapour Carry-Over of High-Molecular-Weight Compounds
Heavy molecules co-evaporate with lighter vapour at high vacuum — downstream contamination.
Rotor Balance with Viscous Product Build-Up at High Speed
Product accumulation on rotor causes vibration and bearing load increase.
CIP Complexity for Pharmaceutical GMP Applications
Narrow wiper gap creates CIP shadow zones requiring validated cleaning protocols.
Solutions
- PTFE or Carbon-Graphite Wiper Blades with Replaceable Inserts: Field-replaceable inserts restore design gap without rotor removal — minimal downtime.
- Internal Short-Path Condenser (Coaxial, <50 mm Vapour Path): Coaxial condenser intercepts high-boiling vapour — eliminates carry-over in molecular distillation.
- Internal Short-Path Condenser (Coaxial, <50 mm Vapour Path): Coaxial condenser intercepts high-boiling vapour — eliminates carry-over in molecular distillation.
- Automatic Rotor Balance Sensor with VFD Speed Trim: Vibration sensor trims rotor speed on imbalance — prevents bearing damage at high viscosity.
- Full CIP with Automated Flushing Solvent Sequence: Automated CIP cycle circulates cleaning solvent through rotor and blade gaps — validated by TOC.
Applications
- Pharmaceutical: API purification, vitamin and hormone concentration, polymer intermediate devolatilisation.
- Food & Beverage: Flavour and aroma concentrate, fatty acid purification, natural wax processing.
- Chemical: Monomer recovery, polymer devolatilisation, resin stripping, heavy residue processing.
- Nutraceuticals: Omega-3 fish oil purification, tocopherol, carotenoid and sterol isolation.
- Cosmetics: Lanolin purification, cosmetic wax and ester concentration, fragrance oil isolation.
Models & Capacities
Model | Type | Scale | Evaporation Capacity [kg/h] | Evaporation Area [m²] | Cylinder Ø [mm] | Cylinder L [mm] | Rotor Speed [RPM] | Jacket Temp [°C] | Vacuum [mbar] | Max Viscosity [cP] | Installed Power [kW] |
|---|---|---|---|---|---|---|---|---|---|---|---|
WFE-LAB-001-S | Standard | Lab | 0.2–5 | 0.01 | Ø80 | 500 | 200–600 VFD | 50–250 | 0.5–500 | <5,000 | 0.12 |
WFE-LAB-010-S | Standard | Lab | 1–20 | 0.1 | Ø120 | 900 | 200–600 VFD | 50–250 | 0.5–500 | <10,000 | 0.37 |
WFE-LAB-001-SP | Short-Path | Lab | 0.1–3 | 0.01 | Ø80 | 500 | 200–600 VFD | 50–250 | 0.001–10 | <5,000 | 0.18 |
WFE-LAB-010-SP | Short-Path | Lab | 0.5–10 | 0.1 | Ø120 | 900 | 200–600 VFD | 50–250 | 0.001–10 | <10,000 | 0.55 |
WFE-PIL-050-S | Standard | Pilot | 5–100 | 0.5 | Ø200 | 1,600 | 200–500 VFD | 50–280 | 0.5–200 | <20,000 | 1.5 |
WFE-PIL-050-SP | Short-Path | Pilot | 3–60 | 0.5 | Ø200 | 1,600 | 200–500 VFD | 50–280 | 0.001–5 | <20,000 | 1.5 |
WFE-PIL-200-S | Standard | Pilot | 20–400 | 2 | Ø350 | 2,400 | 200–450 VFD | 50–300 | 0.5–100 | <30,000 | 4.0 |
WFE-PIL-200-SP | Short-Path | Pilot | 10–200 | 2 | Ø350 | 2,400 | 200–450 VFD | 50–300 | 0.001–5 | <30,000 | 4.0 |
WFE-P-100-S | Standard | Production | 50–1,000 | 10 | Ø500 | 4,500 | 150–400 VFD | 50–320 | 0.5–50 | <40,000 | 11 |
WFE-P-100-SP | Short-Path | Production | 30–500 | 10 | Ø500 | 4,500 | 150–400 VFD | 50–300 | 0.001–5 | <40,000 | 15 |
WFE-P-250-S | Standard | Production | 150–2,500 | 25 | Ø750 | 6,500 | 120–350 VFD | 50–320 | 0.5–30 | <50,000 | 22 |
WFE-LP-500-S | Standard | Large Prod | 300–5,000 | 50 | Ø1,000 | 8,000 | 100–300 VFD | 50–320 | 0.5–20 | <50,000 | 37 |