This case study documents a powder handling automation retrofit for an anonymized bakery manufacturer producing cakes, breads, and pastries across several concurrent production lines. The facility processes a range of powder ingredients — wheat flour, granulated sugar, maltodextrin, milk powder, and food-grade additives — with product formulations that change frequently as new SKUs are introduced.
The plant occupies an older building with limited ceiling clearance and constrained floor space around the mixing area, and the raw material warehouse is located a considerable distance from the production floor. Wijay Systems was engaged to survey the facility, design the conveying and batching process, fabricate the equipment, and manage installation and commissioning as a single scope of work built around a food pneumatic conveying system.
Core Operational Challenges
| Challenge | Description |
|---|---|
| Manual bag-dump dust generation | Open bag-tipping at feed points generated airborne particulate at the transfer station |
| Hygroscopic material behavior | Flour and sugar are prone to moisture pickup and caking during open storage and handling |
| Long supply distance in an old plant | Raw material warehouse sits well outside the production area, with no existing enclosed transfer path |
| Frequent recipe changeovers | Multiple powder ingredients and formulations required manual re-weighing between product runs |
| Retrofit downtime constraint | Installation needed to proceed without an extended full-plant shutdown |
| Limited floor space | Ceiling height and layout around existing mixers constrained equipment placement and pipe routing |
Custom-Engineered Bulk-Material Handling Solution
The process design links dust-free feeding, enclosed conveying, humidity-controlled storage, and automated batching into a single closed-loop line, reducing product contact with operators and ambient air throughout the process. The core transport method is negative-pressure (vacuum) pneumatic conveying through a fully enclosed pipeline, sized to move material over the plant’s actual layout rather than a straight-line distance.
Key System Components
| Module | Function |
| Dust-free feeding station | Bag dump with integrated dust collection and vibrating screen for lump/fiber removal |
| Pneumatic conveying line | Negative-pressure enclosed transport of powder between warehouse and production floor |
| stainless-steel-powder-storage-silos | Food-grade storage with level monitoring, temperature/humidity control, anti-bridging |
| automatic-batching-weighing-system | Multi-tank high-precision weighing, PLC-driven recipe dosing |
| HMI / PLC control panel | Centralized monitoring of levels, flow, temperature/humidity, batching records, fault alarms |
Project-Specific Engineering Difficulties
| Engineering Difficulty | Design Response |
|---|---|
| 95-meter conveying distance through an occupied, older building | Pipe routing followed existing beams and columns instead of requiring new structural openings or major civil work |
| Sizing for multi-line simultaneous draw without oversizing | System designed for 11 t/h conveying capacity with margin for concurrent material draw across production lines |
| Minimizing shutdown exposure during installation | Installation and commissioning sequenced by zone rather than as a single full-plant stoppage |
| Cross-contamination risk across multiple powder types | All product-contact surfaces specified in food-grade stainless steel to support hygiene compliance and formulation separation |
What is the difference between dilute-phase and dense-phase pneumatic conveying for food powders?
Dilute-phase conveying moves material at higher velocity with more air, suited to free-flowing powders, while dense-phase moves material at lower velocity with less air, reducing particle degradation. The right choice depends on the specific powder’s flow characteristics and sensitivity to attrition.
Can an existing plant be retrofitted with a pneumatic conveying system without major civil work?
In many cases, yes. Pipe routing can follow existing structural elements — beams, columns, and equipment layout — rather than requiring new openings, provided the routing plan is developed against an accurate site survey of the building.
How is cross-contamination prevented when multiple powder types run through one system?
Cross-contamination risk is addressed through equipment selection (dedicated storage and weighing tanks per material), food-grade contact surfaces, and cleaning/purge procedures built into the process design rather than relying on manual sequencing alone.
What causes flour or sugar to block a conveying line, and how is it prevented?
Blockages are typically linked to moisture pickup and caking in storage or transfer points. Anti-bridging silo design, humidity control, and conveying velocities matched to the material’s flow properties are the standard mitigations.
How long does installation typically take for a plant that can’t fully shut down?
Timelines vary by scope, but phased, zone-by-zone installation is the common approach for occupied plants, allowing completed sections to run while remaining areas are still being installed.
