Pneumatic Conveying — Dense Phase
Behpoo dense phase systems convey material as slugs at low velocity, so abrasive products stop wearing the pipe and fragile products arrive intact. Capacities to 60 t/h over long distances.
In dense phase conveying, material moves as a series of slugs pushed along the pipe by compressed air, rather than suspended in a fast air stream. Velocity is a fraction of dilute phase — and velocity is what causes wear and breakage.
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That is the whole case. Abrasive minerals stop grinding away pipe bends. Plastic pellets stop generating angel hair. Coffee beans, rice and coated products arrive whole. Blends stop separating in transit.
The mechanism is a pressure vessel rather than a rotary valve: the vessel fills, seals, pressurises and discharges a batch into the line, then repeats. That makes the flow inherently cyclic, so a receiving hopper is usually needed to smooth it out for downstream equipment.
Not every material can be conveyed in dense phase — the material must form stable slugs. Where it will not, [dilute phase](dilute-phase.md) is the answer. Behpoo assesses suitability from material properties and, where needed, a conveying trial.
Benefits & Features
- Capacity to 60 t/h over long distances
- Low velocity — dramatically reduced pipe and bend wear
- Minimal product degradation and no angel hair with pellets
- Blends stay mixed in transit
- Low air consumption per tonne conveyed
- Fully enclosed with no moving parts along the line
- ATEX execution for combustible dust
Product Range
| Type | What it is | Typical use |
|---|---|---|
| Single Pressure Vessel | One vessel fills, pressurises and discharges in a cycle | Standard duty where cyclic flow is acceptable |
| Twin Pressure Vessel | Two vessels alternating so one is always discharging | Near-continuous flow at higher capacity |
| Continuous Dense Phase | Rotary valve feed with air injection along the line | Where a pressure vessel cannot be accommodated |
| Full-Line Concept | Air injection boosters along the pipe maintaining slug integrity | Very long distances and difficult materials |
| Fluidised Dense Phase | Material kept aerated and moved at low velocity in a fluidised state | Very fine powders — cement, fly ash |
Available Options
| Option | Choices |
|---|---|
| Vessel arrangement | Single · Twin alternating · Continuous |
| Air injection | None · Boosters along the line · Full-line concept |
| Vessel certification | Standard · Pressure vessel code certified |
| Pipe material | Carbon steel · SS304 · SS316 · Hardened bends |
| Bends | Long radius · Wear-resistant · Blind tee |
| Receiving | Silo direct · Receiving hopper to smooth cyclic flow |
| Safety | Standard · ATEX with earth bonding and explosion relief |
Technical Specification
| Parameter | Unit | Range |
|---|---|---|
| Capacity | t/h | 1 – 120 |
| Conveying distance | m | 20 – 1,000 |
| Pipe diameter | mm | DN 50 – DN 250 |
| Conveying velocity | m/s | A fraction of dilute phase |
| Conveying pressure | barg | 1 – 6 |
| Air consumption | Nm³/t | 15 – 60 |
| Vessel volume | litre | 50 – 3,000 |
| Cycle time | s | 30 – 180 |
| Pipe material | — | Carbon steel · SS304 · SS316 |
| Vessel certification | — | Pressure vessel code as required |
| Hazardous area | Zone | 20 / 21 / 22 on request |
Areas & Application
Cement & Minerals
Abrasive powder transfer where dilute phase would wear out bends in months, and fluidised dense phase for cement and fly ash.
Polymers & Plastics
Pellet transfer without angel hair — the streamers of melted polymer that dilute phase generates and that then contaminate downstream product.
Food Processing
Coffee beans, rice, cereals and coated products conveyed whole, with blends arriving still mixed.
Chemicals
Fragile crystals and friable products transferred without attrition, in ATEX execution.
Glass & Foundry
Abrasive sand and batch materials at low velocity to control pipe wear.
Petrochemicals
Gentle transfer of friable polymer grades where pellet damage and angel hair matter.
Options & Compliance
- MaterialsCarbon steel · SS304 · SS316; hardened or wear-resistant bends
- Pressure vesselDesigned and certified to the applicable pressure vessel code, with inspection documentation
- Hazardous areaATEX execution with earth bonding and explosion relief
- Control interfaceProfinet · Modbus TCP · EtherNet/IP with cycle control and blockage detection
- StandardsPressure equipment directive or local equivalent · ATEX 2014/34/EU · EN 14491 · ISO 12100
Send us your material and route — we will assess dense phase suitability and size the system.