| Loss-in-Weight Screw Feeder | Approximately 0.1–2,000 kg/h, depending on screw diameter, pitch, and material | Typically ±0.25% to ±1.0% of setpoint after calibration | Free-flowing, cohesive, dusty, and mildly difficult powders; twin-screw designs handle more cohesive materials | Commonly 1 μm–10 mm; verify screw clearance for larger particles | Usually suitable for bulk densities of about 0.1–2.0 kg/L, with calibration for density changes | Approximately 5–500 L | Continuous gravimetric control; automatically compensates for changes in bulk density and refill level | Higher cost and control complexity; check load-cell resolution, refill interruption, screw wear, dust sealing, and minimum stable feed rate |
| Volumetric Screw Feeder | Approximately 0.05–1,500 kg/h, depending on screw geometry and speed | Typically ±1% to ±5% of setpoint, assuming stable bulk density | Free-flowing and moderately cohesive powders with consistent bulk density | Commonly 10 μm–10 mm | Performs best when bulk density and powder aeration remain consistent | Approximately 2–300 L | Simple construction, lower initial cost, easy speed-based control, and compact installation | Output changes when density, moisture, or powder level changes; requires regular calibration and stable hopper conditions |
| Vibratory Feeder | Approximately 0.1–500 kg/h, depending on tray size and powder flowability | Typically ±1% to ±5% of setpoint for free-flowing materials | Dry, free-flowing granules, crystals, pellets, and powders with low cohesion | Commonly 50 μm–10 mm; very fine powders may bridge or fluidize | Best with stable-density materials; performance can decline with highly compressible powders | Approximately 1–100 L | Gentle handling, few moving parts, low shear, and convenient cleaning | Sensitive to powder cohesion, moisture, vibration transmission, and installation rigidity; not ideal for very fine dusty powders |
| Rotary Airlock Feeder | Approximately 0.5–20,000 kg/h, depending on rotor volume and speed | Typically ±2% to ±10% of setpoint; generally used for transfer rather than precision dosing | Dry powders, granules, and dust-collection materials requiring controlled discharge | Commonly 10 μm–15 mm; avoid particles that can damage rotor or housing clearances | Handles a broad density range, but capacity is strongly affected by fill efficiency and leakage | Usually integrated below a hopper, cyclone, or filter; upstream vessel volume varies widely | High capacity, continuous operation, and useful pressure separation between process zones | Not normally the first choice for high-accuracy dosing; check rotor clearance, abrasive wear, air leakage, explosion protection, and product temperature |
| Disc or Rotary-Cup Feeder | Approximately 0.05–200 kg/h, depending on disc speed and cavity volume | Typically ±1% to ±3% after calibration with consistent material | Free-flowing powders, granules, and small particles with relatively stable density | Commonly 50 μm–5 mm | Requires consistent filling of the disc or cups; density variation can affect mass output | Approximately 1–50 L | Accurate intermittent or continuous dosing, clear operating principle, and relatively gentle product handling | Bridging and inconsistent cavity filling can reduce accuracy; check cleanability, cavity size, and maximum allowable particle size |
| Loss-in-Weight Vibratory Feeder | Approximately 0.1–300 kg/h, depending on tray design and material properties | Typically ±0.5% to ±2% of setpoint after calibration | Free-flowing powders and granules where low shear and low mechanical contact are important | Commonly 50 μm–10 mm | Suitable for stable-density materials; gravimetric control helps correct for gradual density changes | Approximately 5–150 L | Combines gravimetric monitoring with gentle conveying and relatively simple product-contact geometry | Very cohesive or highly aerated powders may require agitation, vibration isolation, or an alternative screw-based design |
| Pneumatic Powder Dosing System | Approximately 0.1–5,000 kg/h, depending on conveying distance, air rate, and dosing device | Typically ±1% to ±5% for controlled dosing; conveying-only systems may be less precise | Dry powders and granules compatible with pneumatic conveying | Commonly 1 μm–10 mm; assess friability, electrostatic behavior, and conveying velocity | Can handle wide density ranges, but air entrainment changes apparent flow behavior | Approximately 5–1,000 L, depending on the pressure or vacuum vessel | Flexible routing, enclosed transfer, long-distance conveying, and reduced mechanical contact | Requires compressed air or vacuum; check filtration, moisture control, wear, dust explosion protection, and product degradation |