RELEASE MATERIAL CONSISTENTLY
Match bulk bag discharge and hopper arrangements to the material’s flow behaviour.
Non-Free-Flowing Materials
RELIABLE CONVEYING FOR NON-FREE-FLOWING MATERIALS
Keep production supplied by addressing difficult discharge and conveying together.
Bridging, rat-holing and inconsistent discharge can interrupt production before material reaches the conveyor. UniTrak combines conveying equipment with application-specific bulk bag, hopper and feeding arrangements. We review the complete material path to establish a reliable supply into the conveyor and onward to your process.
Materials
KEEP MATERIAL MOVING FROM RECEIVING TO DISCHARGE
CONTROL THE SUPPLY
Address surging and starvation at the source so the conveyor receives material consistently.
CONNECT THE COMPLETE PROCESS
Coordinate receiving, flow assistance, conveying and downstream equipment around the required production rate.
Materials
MANY MATERIALS LOOK FLOWABLE UNTIL THEY ARE PUT IN A HOPPER
Poor gravity flow can result from particle size, shape, cohesiveness, density or process condition.
These are representative material families only. Suitability requires application review.
Non-free-flowing materials primarily have poor gravity flow, bridging, rat-holing or inconsistent discharge from storage or feeding equipment. Sticky & Adhesive Materials primarily adhere to equipment surfaces. Packing, Caking & Smearing Materials undergo compaction, agglomeration or physical change caused by pressure, time or mechanical handling. A material may exhibit more than one characteristic; this page focuses on reliable introduction into and movement through the conveying process.
FINE & COHESIVE POWDERS
Small particles can interact strongly enough to resist gravity flow.
Fine powders may bridge over outlets, discharge intermittently or form stable flow channels within storage vessels.
Their behavior can be influenced by particle size, moisture, aeration and time under storage.
Examples may include:
- Fine food powders
- Chemical powders
- Mineral powders
- Pigments
- Additives
- Specialty ingredients
Common concerns: Bridging • Rat-Holing • Cohesion • Surging • Dust
LIGHT & LOW-BULK-DENSITY MATERIALS
Light materials may not develop enough gravitational force to discharge consistently.
Low-density products can be difficult to move from hoppers because their own weight provides relatively little force to overcome particle interaction.
Some may also aerate or become easily disturbed.
Examples may include:
- Light powders
- Flakes
- Expanded ingredients
- Low-density granules
- Selected recycled materials
Common concerns: Poor Gravity Flow • Aeration • Bridging • Inconsistent Feed • Bulk Density
FLAKES, FIBERS & IRREGULAR PARTICLES
Particle shape can prevent material from moving freely.
Flat, elongated, fibrous or irregular particles may interlock with one another, creating flow restrictions that would not occur with rounded granules.
These materials can be difficult to predict from bulk density alone.
Examples may include:
- Flaked materials
- Fibrous ingredients
- Irregular granules
- Shredded products
- Selected biomass or recycled products
Common concerns: Interlocking • Bridging • Hopper Discharge • Variable Flow • Feeding
FOOD & NUTRITION POWDERS
Many food powders combine poor flow with cleaning and product-quality requirements.
Fine ingredients can become cohesive because of moisture, fat content, particle size or formulation.
The handling system must consider both reliable flow and the requirements of the surrounding process.
Examples may include:
- Protein powders
- Milk-based powders
- Starches
- Seasoning blends
- Nutritional ingredients
- Bakery powders
Common concerns: Cohesion • Bridging • Flow Consistency • Cleaning • Dust
CHEMICAL & INDUSTRIAL POWDERS
Process powders can vary from free-flowing to highly cohesive.
Chemical and industrial materials may resist gravity flow because of fine particle size, irregular shape, electrostatic behavior or moisture sensitivity.
The specific product should be evaluated rather than assuming all powders will behave similarly.
Examples may include:
- Specialty chemicals
- Pigments
- Additives
- Industrial powders
- Fine crystalline materials
- Process intermediates
Common concerns: Flow Reliability • Bridging • Dust • Material Compatibility • Testing
RECYCLED & VARIABLE MATERIALS
Inconsistent particle characteristics can produce inconsistent flow.
Recovered and recycled products may contain a broad mix of particle sizes, shapes and densities.
A material may flow acceptably in one batch and poorly in another if its composition changes.
Examples may include:
- Recycled process materials
- Recovered powders
- Mixed industrial materials
- Shredded products
- Reclaimed ingredients
Common concerns: Variability • Bridging • Particle Shape • Bulk Density • Testing
Materials
CHOOSE THE CONVEYING METHOD AFTER YOU UNDERSTAND HOW THE MATERIAL WILL REACH IT
For non-free-flowing products, reliable material introduction is often just as important as conveyor capacity.
Reliable discharge and the right conveying method work together. Select the equipment around how your material leaves storage, enters the conveyor and reaches the next process.
TIPTRAK® BUCKET ELEVATOR
TipTrak carries material in continuous, interlocking buckets through horizontal and vertical sections. Controlled feeding loads the buckets consistently, while application-specific discharge arrangements address how the material leaves the conveyor.
EXPLORE TIPTRAK
POWDERFLIGHT AEROMECHANICAL CONVEYOR
Powderflight’s rope-and-disc assembly creates an air stream that transports compatible powders through an enclosed tube. Match the infeed hopper and any required flow assistance to the material so it reaches the conveyor reliably.
EXPLORE POWDERFLIGHT
UNIFLEX FLEXIBLE SCREW CONVEYOR
UniFlex draws material from a charged hopper using a rotating flexible screw. Select the hopper, flow assistance and screw arrangement around the powder’s behaviour and required conveying rate.
EXPLORE UNIFLEX
KLEANTRAK SANITARY BELT CONVEYOR
KleanTrak supports compatible materials on an accessible belt. Controlled feeding distributes material onto the belt, combining supported movement with direct access for inspection and cleaning.
EXPLORE KLEANTRAK
BAGSTANDER BULK BAG HANDLING
Bagstander connects bulk bag unloading with downstream conveying. Application-specific bag manipulation and hopper flow assistance help loosen compacted material and promote discharge into the process.
EXPLORE BAGSTANDERCoordinate receiving, hopper discharge and conveying through our integrated systems approach.
Materials
WHERE NON-FREE-FLOWING MATERIALS INTERRUPT THE PROCESS
The biggest challenge is often getting a consistent supply of material into the conveyor.
BULK BAG DISCHARGE
Difficult flow can begin before the material ever reaches a hopper.Some materials compact during storage or transportation and resist leaving the bulk bag under gravity alone.
For suitable applications, Bagstander systems can use bag manipulators to compress the bag and help loosen the material, promoting more reliable discharge into downstream equipment.
Consider: Compaction • Bulk Bag Discharge • Bag Manipulation • Material Loosening • Process Reliability
HOPPER DISCHARGE
Reliable conveying begins with reliable material release.If material bridges, rat-holes or settles poorly in a hopper, the downstream conveyor cannot maintain a consistent rate regardless of its available capacity.
Depending on the application, UniTrak hoppers can incorporate vibrators or fluidization pads to help promote material movement toward the outlet.
Hopper geometry, outlet configuration, storage conditions and actual material behavior should all be considered together.
Consider: Bridging • Rat-Holing • Hopper Geometry • Vibrators • Fluidization • Material Behavior
MATERIAL CONDITION
Material behavior can change while it waits.Some products become harder to discharge after sitting in a hopper or bulk bag.
Time under load, moisture, temperature and aeration can all change flow characteristics.
The application should reflect actual production and storage conditions rather than only freshly sampled material.
Consider: Storage Time • Moisture • Temperature • Compaction • Aeration
COMPLETE SYSTEM DESIGN
A conveyor cannot correct every upstream flow problem.Bulk bag unloading, storage, hopper discharge, flow assistance and conveying should be considered as one connected system.
Selecting a larger conveyor alone will not solve a material that never reaches the conveyor consistently.
Consider: Bulk Bag Receiving • Hopper Discharge • Flow Aids • Conveying • Downstream Process
SOLVE THE FLOW PROBLEM BEFORE IT BECOMES A CONVEYOR PROBLEM
For non-free-flowing materials, reliable performance depends on understanding how the material moves from storage or bulk bags into the conveying system.
UniTrak can combine conveying equipment with application-specific flow-assistance features such as bag manipulators, hopper vibrators and fluidization pads where appropriate to help create a more reliable material path.
Materials
NON-FREE-FLOWING MATERIAL HANDLING GUIDANCE
DIFFICULT POWDERS
Fine powders can resist gravity flow because of cohesion, moisture and particle characteristics. Powderflight provides enclosed aeromechanical conveying for compatible materials, with the hopper and flow-assistance arrangement selected around reliable material supply.
Read Difficult-Powder Guidance
BULK BAG & HOPPER DISCHARGE
Reliable conveying starts with reliable material release. Review hopper geometry, outlet design, storage conditions and appropriate flow assistance alongside the conveyor to address bridging, rat-holing and inconsistent discharge.
Read Hopper-Flow GuidanceMaterials
OBSERVE HOW YOUR MATERIAL FEEDS AND DISCHARGES
Use representative material to assess feeding, conveying and discharge in suitable available equipment. Share the storage conditions and existing flow problem so the trial addresses the behaviour affecting your process.
Materials
NON-FREE-FLOWING MATERIAL CONVEYING FAQ
What is a non-free-flowing material?
A non-free-flowing material does not move consistently under gravity. It may bridge above an outlet, form a narrow rat-hole through stored material, discharge intermittently or require additional assistance to move reliably into downstream equipment.
What causes a material to stop flowing?
Flow behavior can be influenced by particle size, shape, cohesiveness, moisture, bulk density, surface texture, storage time, compaction and hopper geometry. Different materials can stop flowing for very different reasons.
What is bridging?
Bridging occurs when material forms a stable arch across an outlet and supports itself rather than falling through the opening.
What is rat-holing?
Rat-holing occurs when material flows through a narrow channel while a significant portion of the surrounding material remains stationary in the hopper or storage vessel.
Why does inconsistent material flow affect a conveyor?
A conveyor can only move the material that reaches it. Bridging, rat-holing or surging upstream can cause the conveyor to alternate between underloading and sudden material surges even when the machine has sufficient capacity.
Can TipTrak handle non-free-flowing materials?
Yes. TipTrak carries compatible non-free-flowing materials in buckets once they are introduced consistently. The hopper, controlled feeding and discharge arrangements are selected around the material’s behaviour and required throughput.
Does TipTrak's controlled bucket movement limit conveying rate?
No. TipTrak uses deep buckets to carry substantial material volume while maintaining controlled movement, allowing high conveying rates without requiring high belt speed.
Can Powderflight handle non-free-flowing powders?
Powderflight conveys compatible difficult powders through an enclosed tube using an air stream generated by its rope-and-disc assembly. Reliable hopper discharge is important. Flow assistance is selected for the application; a separate metering feeder is not inherently required.
Can UniFlex handle cohesive powders?
UniFlex can be considered for many compatible powders and bulk solids. Suitability depends on the material's behavior and its response to flexible screw conveying. Maintaining a reliable supply of material in the hopper around the screw inlet remains important.
Can KleanTrak handle irregular or cohesive material?
KleanTrak can be considered for compatible materials that can be presented consistently onto the belt. Supported belt conveying may be useful for some irregular or difficult products because the material is carried through the conveying path.
Can Bagstander help with material that will not leave a bulk bag easily?
Yes. For suitable applications, Bagstander systems can incorporate bag manipulators that compress the bulk bag to help loosen the material and promote discharge.
Can UniTrak provide flow aids for difficult hopper discharge?
Yes. Depending on the application, UniTrak hoppers can incorporate vibrators or fluidization pads to help promote material movement toward the outlet.
Is a non-free-flowing material the same as a sticky material?
No. A non-free-flowing material primarily has difficulty moving under gravity. A sticky material primarily adheres to itself or equipment surfaces. Some products exhibit both characteristics.
Can UniTrak test a non-free-flowing material?
Yes. Suitable customer materials can be evaluated by UniTrak using available test equipment. Testing can provide useful information about material behavior and conveying suitability before the final solution is selected.
What information should I provide for a non-free-flowing material application?
Provide the material name, SDS where available, particle size and shape, bulk density, required conveying rate, conveying distance and elevation, description of current bridging or flow problems, bulk bag or hopper arrangement, storage conditions, material temperature, upstream equipment, downstream equipment and any current operator interventions or flow aids.
Materials
NON-FREE-FLOWING MATERIAL HANDLING RESOURCES
Why Material Testing Should Happen Before You Buy a Conveyor
Review how actual-material evaluation can reveal flow, discharge and equipment-suitability issues before selection.
Read resource
Storage Bins and Hoppers for Bulk Materials
Explore cohesive materials, gravity flow, bridging, rat-holing and the interaction between hopper discharge and downstream equipment.
Read resourceHandling Difficult Powders with Aeromechanical Conveyors
Consider poor-flowing powder characteristics, controlled infeed, appropriate hopper flow assistance and actual-material testing for Powderflight.
Read resource
Discharging Ingredients with a Bagstander Bulk Bag Unloader
Review bulk-bag receiving, controlled ingredient discharge and integration with downstream conveying equipment.
Read resource
Powder Handling: Flexible Screw or Aeromechanical Conveyor?
Compare UniFlex and Powderflight suitability for powder behavior, hopper feeding and the role of testing in selection.
Read resourceDISCUSS YOUR NON-FREE-FLOWING MATERIAL
Tell us what you are conveying, where the flow stops and the rate your process needs. Include the receiving arrangement and conveying route so UniTrak can review the material path and recommend the right equipment.
