What It Is
How It Works
What It Is
A twin screw micro feeder meters powder with two intermeshing co-rotating screws that self-wipe each other, preventing material build-up and rotation of cohesive powder with the screw. It is the standard choice for sticky, bridging, fatty, and fibrous powders that defeat single screws, covering 0.04 to 300 litres per hour in hygienic execution.
How It Works
The intermeshing screw pair conveys powder in closed C-shaped chambers formed between the flights and the barrel. Each screw continuously wipes the root of the other, stripping adhered powder and breaking cohesive plugs. Fill is assisted by a horizontal agitator or flexible hopper paddles, and a servo drive turns the pair across a wide speed range with volume per revolution fixed by the screw geometry.
Challenges
Cohesive Powder Rotating with a Single Screw
Sticky powders grip a single screw and rotate with it instead of advancing, collapsing the feed rate.
Build-Up Bridging the Hopper Throat
Fatty and hygroscopic powders bridge across the narrow throat above the screws, starving the flights.
Shear Damage to Fragile Agglomerates
The intermesh zone applies shear that can fracture instantised and granulated products.
Higher Cost and Cleaning Complexity
Two screws, timing gears, and the intermesh geometry add cost and cleaning surfaces over single screw designs.
Fibre Wrap at the Screw Root
Fibrous additives wind around screw roots at the intermesh, progressively choking the chambers.
Solutions
- Self-Wiping Co-Rotating Screw Pair: The intermeshing pair strips powder from each screw every revolution, maintaining positive conveyance of cohesive products.
- Agitated or Massaged Hopper Above the Throat: A slow horizontal agitator or externally massaged flexible hopper keeps the throat live without compacting the powder.
- Deep-Flight Low-Speed Screw Selection: Deep, coarse-pitch screws running slower move the same rate with reduced intermesh shear, protecting agglomerates.
- Cantilevered Screws with Front Pull-Out: Cantilever-mounted screws releasing from the front, with no outboard bearing, cut strip-down to a single-step operation.
- Cut-Flight Fibre-Duty Screw Profile: Interrupted cut-flight profiles shear off winding fibres at each intermesh pass, keeping chambers open.
Applications
- Pigment and Dye Powder Dosing: Reliable metering of cohesive pigments into masterbatch and coating processes.
- Fatty Dairy and Cocoa Powder Feed: Feeding whole milk powder, cocoa, and fat-filled premixes that bridge single screws.
- Gum and Thickener Addition: Metering xanthan, guar, and CMC into hydration and blending systems.
- API and Potent Compound Dosing: Contained metering of cohesive actives in continuous pharma lines.
- Fibre and Flake Additive Feed: Feeding cellulose fibre and flake additives into compounding extruders.
Model Range and Capacity: JBM-MF-T Series
Basis: Rates at 2 to 100 percent screw speed, kg/h at 0.6 t/m3, SS 316L contact parts.
| Model | Screw Dia (mm) | Feed Rate (L/h) | Rate (kg/h) @ 0.6 t/m3 | Hopper (L) | Drive (kW) | Contact Material |
|---|---|---|---|---|---|---|
| JBM-MF-T12 | 2 x 12 | 0.04 – 3 | 0.02 – 1.8 | 5 | 0.25 | SS 316L |
| JBM-MF-T20 | 2 x 20 | 0.4 – 18 | 0.24 – 11 | 10 | 0.37 | SS 316L |
| JBM-MF-T30 | 2 x 30 | 1.5 – 60 | 0.9 – 36 | 25 | 0.55 | SS 316L |
| JBM-MF-T40 | 2 x 40 | 4 – 150 | 2.4 – 90 | 50 | 0.75 | SS 316L |
| JBM-MF-T50 | 2 x 50 | 8 – 300 | 4.8 – 180 | 75 | 1.1 | SS 316L |