A toothed rotor–stator dry colloid mill uses concentric rings of interlocking teeth on a high-speed rotor (3,000–15,000 RPM) and stationary stator to subject dry powder to high-frequency impact, shear, and attrition forces as material passes radially through the tooth rings. Processing 1–500 kg/h across 0.1–5 mm feed particle size, it delivers D90 of 20–200 µm — the standard pharmaceutical and food-grade dry milling configuration for deagglomeration and intermediate size reduction.
Dry feed enters the mill axially through the rotor hub; centrifugal force drives particles outward through successive concentric tooth rings — each ring delivering progressively intense impact and shear. Gap between rotor and stator tooth rings (0.1–5 mm, adjustable) determines maximum particle size output. High rotor peripheral velocity (50–150 m/s tip speed) generates 10³–10⁵ impact events per second per particle. A downstream bag filter or cyclone collects milled powder; milling chamber is jacketed for temperature control below 40°C.
Challenges
Gap Setting Sensitivity
0.025 mm gap tolerance requires precision adjustment; minor misalignment causes rotor-stator contact.
Waxy Material Build-Up in Grooves
Lipid-based or waxy APIs soften under frictional heat and pack into groove channels.
Limited Throughput vs. Toothed Mill
Smaller processing surface area limits maximum throughput compared to toothed rotor–stator.
Groove Wear Changes PSD Over Time
Progressive groove wear widens effective gap; D90 drifts coarser over production campaign.
CIP Access to Narrow Cone Gap
Grooved surface geometry requires validated CIP spray pattern to reach all surfaces.
Solutions
- Micrometer Gap Adjustment Mechanism: Precision screw adjustment with dial gauge: ±0.005 mm reproducible gap setting.
- Liquid Nitrogen Feed Pre-Cooling: Cryogenic pre-cooling of waxy or heat-sensitive feed prevents groove packing and sticking.
- Hard Chrome or DLC-Coated Cone Surfaces: Diamond-like carbon coating extends groove life to >5,000 production hours.
- Inline PSD Sensor with Automatic Gap Feedback: Laser diffraction sensor on outlet triggers gap adjustment to maintain D90 ±5%.
- Quick-Release Cone Extraction Tool: Factory-supplied extraction collar removes rotor cone in <10 minutes for full CIP access.
Applications
- Pharmaceutical: Fine API milling for inhalation (D90 <20 µm), oral solid dosage size reduction, heat-sensitive compound milling.
- Cosmetics: Ultra-fine pigment milling, sunscreen particle size reduction, luxury powder formulation.
- Food & Beverage: Cocoa powder, dried herb, and spice ultra-fine milling for premium product applications.
- Nutraceuticals: Plant extract ultra-fine milling, bioavailability enhancement particle size reduction.
- Chemical: Catalyst ultra-fine powder production, specialty pigment sub-50 µm size reduction.
Models & Capacities
| Type 1 — Toothed Disc Dry Colloid Mill: Models & Capacities (1 kg/h to 20,000 kg/h) | ||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Model | Scale | Throughput [kg/h] | Feed Size Max [mm] | Product Size D97 [um] | Rotor Dia [mm] | Rotor Speed [RPM] | Tip Speed [m/s] | Gap [mm] | Motor [kW] | Inlet Dia [mm] | Outlet Dia [mm] | Overall L [mm] | Overall H [mm] | Weight [kg] |
| CMD-TD-LAB-75 | Lab | 1-10 | 1 | 50-500 | Dia75 | 6,000-18,000 | 23-71 | 0.1-2 | 0.37 | Dia30 | Dia30 | 480 | 420 | 18 |
| CMD-TD-LAB-130 | Lab | 5-50 | 3 | 30-400 | Dia130 | 5,000-15,000 | 34-102 | 0.1-2 | 0.75 | Dia50 | Dia50 | 620 | 520 | 42 |
| CMD-TD-PIL-180 | Pilot | 20-150 | 5 | 20-300 | Dia180 | 4,000-12,000 | 38-113 | 0.1-3 | 1.5 | Dia65 | Dia65 | 780 | 650 | 90 |
| CMD-TD-PIL-250 | Pilot | 50-300 | 8 | 15-250 | Dia250 | 3,600-10,800 | 47-141 | 0.1-3 | 3.0 | Dia80 | Dia80 | 920 | 780 | 165 |
| CMD-TD-P-300 | Production | 100-600 | 10 | 10-200 | Dia300 | 3,000-9,000 | 47-141 | 0.1-3 | 5.5 | Dia100 | Dia100 | 1,100 | 920 | 280 |
| CMD-TD-P-360 | Production | 200-1,000 | 12 | 10-180 | Dia360 | 2,800-8,400 | 53-158 | 0.1-4 | 7.5 | Dia125 | Dia125 | 1,280 | 1,050 | 420 |
| CMD-TD-P-450 | Production | 400-2,000 | 15 | 8-150 | Dia450 | 2,500-7,500 | 59-177 | 0.1-4 | 11 | Dia150 | Dia150 | 1,500 | 1,200 | 680 |
| CMD-TD-P-550 | Production | 600-3,000 | 18 | 6-120 | Dia550 | 2,200-6,600 | 63-190 | 0.1-5 | 15 | Dia175 | Dia175 | 1,750 | 1,380 | 980 |
| CMD-TD-P-650 | Production | 1,000-5,000 | 20 | 5-100 | Dia650 | 2,000-6,000 | 68-204 | 0.1-5 | 22 | Dia200 | Dia200 | 2,000 | 1,600 | 1,400 |
| CMD-TD-LP-750 | Large Prod | 1,500-7,500 | 25 | 5-80 | Dia750 | 1,800-5,400 | 71-212 | 0.1-6 | 30 | Dia225 | Dia225 | 2,300 | 1,850 | 2,100 |
| CMD-TD-LP-900 | Large Prod | 2,500-12,000 | 30 | 4-60 | Dia900 | 1,500-4,500 | 71-212 | 0.1-6 | 45 | Dia250 | Dia250 | 2,700 | 2,150 | 3,200 |
| CMD-TD-LP-1100 | Large Prod | 4,000-20,000 | 35 | 3-50 | Dia1100 | 1,200-3,600 | 69-207 | 0.1-8 | 75 | Dia300 | Dia300 | 3,200 | 2,550 | 5,000 |