A continuous coater is a long, perforated horizontal drum through which tablets flow at a steady rate while being coated and dried in a single pass. Rated for 100–6,000 kg/h, it serves high-volume products where batch coaters become a bottleneck. It delivers uniform film coats at low weight gain (2–4%) with near plug-flow residence time and minimal operator intervention.
Tablets enter from a loss-in-weight feeder at the inlet end of a slightly inclined drum rotating at 2–14 RPM. Internal flights and weirs convey the bed forward while a manifold of 6–30 spray guns applies coating along the drum length. Heated air (50–80°C) passes through the perforated shell into exhaust plenums. Residence time of 15–40 min is set by feed rate, drum speed, inclination, and weir height, and coated tablets discharge continuously to packing.
Challenges
Residence Time Distribution
Back-mixing broadens RTD, producing under-coated and over-coated tablets.
Start-Up and Shut-Down Waste
Tablets coated before steady state must be segregated and rejected.
Feed Rate Disturbances
Upstream press variation changes bed depth and weight gain.
Spray Zone Coordination
Many guns along the drum need balanced flow and atomization.
Product Changeover
Long drum and ducts extend cleaning downtime between products.
Solutions
- Adjustable Weirs and Flights: Narrow RTD toward plug flow for weight-gain RSD below 5%.
- Automated Divert Gates: PLC routes non-conforming start and stop tablets to reject bins.
- Loss-in-Weight Feeder + Buffer Hopper: Stabilizes inlet mass flow within ±1%.
- Individual Gun Group Control: Mass flow meters per gun group keep spray distribution uniform.
- Full WIP with Drain Slope: Automated drum, plenum, and duct wash cuts changeover to one shift.
Applications
- Pharmaceutical: High-volume OTC analgesic, antacid, and generic tablet film coating.
- Nutraceuticals: Large-volume vitamin and mineral tablet coating.
- Confectionery: Continuous coating of compressed mints and chewing gum pellets.
- Chemical & Detergent: Dishwasher, laundry, and water-treatment tablet coating.
- Agro: Seed and fertilizer granule film coating at high throughput.
Models & Capacities: Laboratory to Large Production
| Model | Scale | Pan Ø [mm] | Pan L [mm] | Output [kg/h] | Resid. Time [min] | Pan Speed [RPM] | Spray Guns | Inlet Air [CMH] | Heater [kW] | Overall L×W×H [mm] | Weight [kg] |
|---|---|---|---|---|---|---|---|---|---|---|---|
| CTC-0100 | Pilot | 860 | 2,650 | 100 | 15–30 | 3–14 | 6 | 760 | 15 | 4150×2150×2350 | 3,800 |
| CTC-0250 | Pilot | 990 | 3,200 | 250 | 15–30 | 3–13 | 8 | 1,750 | 35 | 4700×2300×2500 | 5,450 |
| CTC-0500 | Production | 1,100 | 3,700 | 500 | 15–30 | 3–13 | 10 | 3,200 | 65 | 5200×2400×2600 | 7,200 |
| CTC-0750 | Production | 1,170 | 4,000 | 750 | 20–35 | 2–12 | 12 | 4,650 | 95 | 5500×2450×2650 | 8,500 |
| CTC-1000 | Production | 1,230 | 4,250 | 1,000 | 20–35 | 2–12 | 14 | 6,000 | 120 | 5750×2550×2750 | 9,500 |
| CTC-1500 | Production | 1,300 | 4,650 | 1,500 | 20–35 | 2–12 | 16 | 8,650 | 170 | 6150×2600×2800 | 11,200 |
| CTC-2000 | Production | 1,360 | 4,950 | 2,000 | 20–35 | 2–11 | 18 | 11,200 | 220 | 6450×2650×2850 | 12,500 |
| CTC-2500 | Large Prod | 1,410 | 5,150 | 2,500 | 20–40 | 2–11 | 20 | 13,700 | 270 | 6650×2700×2900 | 13,700 |
| CTC-3000 | Large Prod | 1,450 | 5,350 | 3,000 | 20–40 | 2–11 | 22 | 16,200 | 320 | 6850×2750×2950 | 14,800 |
| CTC-4000 | Large Prod | 1,520 | 5,700 | 4,000 | 20–40 | 2–11 | 24 | 20,900 | 420 | 7200×2800×3000 | 16,600 |
| CTC-5000 | Large Prod | 1,570 | 6,000 | 5,000 | 20–40 | 2–11 | 28 | 25,600 | 510 | 7500×2850×3050 | 18,100 |
| CTC-6000 | Large Prod | 1,620 | 6,200 | 6,000 | 20–40 | 2–10 | 30 | 30,200 | 600 | 7700×2900×3100 | 19,500 |