A flexible fabric silo is a square-section storage bag of breathable antistatic polyester (Trevira type) fabric tensioned inside a bolted steel or aluminium frame. The permeable wall releases conveying air through the fabric itself, removing the need for a roof filter in many duties. It suits indoor food-grade powder storage from 2 to 60 m3 at low capital cost.
The fabric body hangs from a corner-mounted frame and forms an integral steep hopper at its base. During pneumatic filling, conveying air permeates outward through the fabric wall while powder is retained, so the silo self-vents. The breathable wall also equalises humidity, limiting condensation. Discharge is by gravity through a bottom spigot into a screw or vibratory feeder, often with an external vibrator on the frame.
Challenges
Fabric Permeability Loss
Fat-containing or very fine powders progressively blind the fabric weave, reducing self-venting capacity and pressurising the bag during filling.
Limited Overpressure Tolerance
Fabric bodies cannot withstand significant internal pressure; a blocked vent path during tanker blow-in can burst seams.
No Wet Cleaning Capability
Fabric bodies cannot be CIP washed, restricting use where wet cleaning between products is mandatory.
Rodent and Insect Vulnerability
Fabric walls can be penetrated by pests in poorly controlled warehouse environments, compromising food safety.
Frame Corner Abrasion
Repeated fill and discharge cycles flex the fabric against frame corners, wearing the weave at contact lines over years of service.
Solutions
- Fabric Grade Matched to Powder: Selecting weave permeability and antistatic grade for the specific powder, with periodic external vacuum cleaning, maintains venting performance.
- Filling Line Pressure Interlock: A pressure switch on the fill line trips the conveying blower at low bag overpressure, protecting seams from blocked-vent events.
- Replaceable Body with Dry Cleaning Regime: Managing the fabric body as a replaceable element with documented dry cleaning and inspection intervals covers hygiene without wet washing.
- Pest-Controlled Room Housing: Installing fabric silos inside pest-managed rooms with sealed floors and door discipline protects the fabric from rodent damage.
- Wear Sleeves at Frame Contact Lines: Sacrificial fabric wear sleeves at corner contact points extend body life and are replaceable without changing the main body.
Applications
- Bakery Flour and Sugar Indoor Storage: In-plant storage of flour and sugar at bakeries receiving bulk tanker deliveries without external silo civil work.
- Milk Powder Buffer at Dairy Plants: Indoor buffering of milk powders between reception and blending where breathable walls limit condensation.
- Plastic Powder Storage at Rotomoulders: Storage of PE rotomoulding powders beside processing machines with minimal installation cost.
- Starch and Ingredient Storage: Storage of starches and minor food ingredients at snack and convenience food plants.
- Feed Supplement Storage: Indoor storage of feed premixes and supplements at compound feed and integrator facilities.
Model Range and Capacity: JBM-FS Series
Basis: Square section, integral 60 degree fabric hopper, working volume 90 percent of gross, capacity at 0.55 t/m3.
| Model | Section (m) | Body Ht (m) | Overall Ht (m) | Gross Vol (m3) | Working Vol (m3) | Capacity (t) @ 0.55 t/m3 |
|---|---|---|---|---|---|---|
| JBM-FS-05 | 1.5 x 1.5 | 2.0 | 3.5 | 5.5 | 4.9 | 2.7 |
| JBM-FS-12 | 2.0 x 2.0 | 2.5 | 4.4 | 12.3 | 11.1 | 6.1 |
| JBM-FS-23 | 2.5 x 2.5 | 3.0 | 5.4 | 23.3 | 20.9 | 11.5 |
| JBM-FS-39 | 3.0 x 3.0 | 3.5 | 6.3 | 39.3 | 35.4 | 19.4 |
| JBM-FS-60 | 3.5 x 3.5 | 4.0 | 7.3 | 61.4 | 55.2 | 30.4 |