Pneumatic conveying
Tried and tested pressure and vacuum conveying systemsIn industry settings, materials handling technology has the task of moving the materials or goods to be conveyed to the places where they are needed in production or in the warehouse. Conveyor technology can be found in every stage of production. Solving the problems of material flow is an important task when planning a production system.
Systems for every task
from Hosokawa SolidsEvery bulk solid has its own special requirements for a conveyor system. To meet these requirements, we offer our customers a variety of tried and tested pneumatic conveying systems with components for pneumatic pressure and vacuum conveying from our own production. This enables us to find the right solution for every product and every specific task.
Solids Fly Pneu: Dilute phase conveying
Classic dilute phase conveying system for vacuum and pressure operation. Particles and particle clouds or strands are carried by the airflow.
Advantages:
- simple design, reliable operation and low-maintenance
- long service life, depending on wall and bulk solid pairing
- affordable
Suitable for: flours, grains, semolina, dusts, chips, powders
Solids Fluid Pneu: Dense phase pressure conveying
Pressure or vacuum conveying system: Fluidised powders are conveyed as a homogeneous material/air mixture using the push force.
Advantages:
- proven, maintenance-friendly design
- low gas consumption
- affordable
Suitable for: cement, limestone powder, fly ash, bentonite, quicklime, hydrated lime, adsorbent, powder, terephthalic acid, chalk
Solids Vacu Fill: Dense phase vacuum conveying
Vacuum conveying system: The products are conveyed fluidised or in a flow through the use of vacuum force.
Advantages:
- low overall height at the feeding point
- versatile and affordable solution for shorter conveying distances
Suitable for: dusts, plastic granules, fibres, minerals, flours, semolina, food granules
Solids Step Pneu: Push conveying
Pressure conveying system: With indicated plug formation. Granular products with a narrow grain spectrum are conveyed through in a flow and "pushed" as columns or plugs. The plug flow is indicated by air pulses.
Advantages:
- gentle, low-wear conveying
- low operating costs
- simple, robust and sophisticated design
Suitable for: sands, granules, ash, nuts, peas, beans, HOK, tablets, pastilles, coffee beans
Solids Split Pneu: Dense phase conveying with bypass system
Nozzles or boosters break up longer plugs to prevent blockages with difficult bulk solids.
Advantages:
- suitable for difficult bulk solids
Suitable for: minerals, titanium dioxide, metal oxides, chalk, paste PVC, powder soot, lead oxide, metal powder, milk powder
Solids Vacu Dense: Vacuum plug conveying with impulse valve and pressure bypass system
Bypass system, vacuum suction conveying system: For slow and gentle vacuum conveying. Blank casing system.
Advantages:
- low overall height at the feeding point
- segregation-free conveying due to stable product plugs in the conveying line
- gentle transport of sensitive products due to low conveying speed
Suitable for: spray granulation, instant products, hard minerals, milk powder, sands, granulates, ash, pulses, flakes, chips, pelletised carbon black, adipic acid
Solids Vibro Puls Pneu: Plug conveying with bypass system, impulse valve and relay stations (pressure conveying system)
Non-flowable products are introduced into the conveying systems through vibration and pressure, plugs are created and retained and as such pushed through the conveying system without segregation.
Suitable for: moist sand, centrifuge wet solids, cohesive products, mixtures, prepared mixes, dry plaster with lightweight materials, recycled materials, glass shards, coal, coke
Advantages:
- segregation-free conveying due to stable product plugs in the conveying line
- gentle transport of sensitive products due to low conveying speed
- low-wear conveying system due to low conveying speed, pure linear movement of the material plugs
- Start-up of a filled conveying system possible after power- or supply air failure
Solids Puls Pneu: Plug conveying with bypass system, impulse valve and relay stations (slow pressure conveying system).
Non-flowable products are introduced into the conveying systems through vibration and pressure, plugs are created and retained and as such pushed through the conveying system without segregation.
Suitable for: moist sand, centrifuge wet solids, cohesive products, mixtures, prepared mixes, dry plaster with lightweight materials, recycled materials, glass shards, coal, coke
Advantages:
- segregation-free conveying due to stable product plugs in the conveying line
- gentle transport of sensitive products due to low conveying speed
- low-wear conveying system due to low conveying speed, pure linear movement of the material plugs
- Start-up of a filled conveying system possible after power- or supply air failure
Solids Truck Discharge: Plug conveying with bypass system, impulse valve and relay stations (pressure conveying system)
solids Puls Pneu using the silo vehicle as a pressure container.
Suitable for: sugar, spray granulation, instant products, no fat milk powders, silicon carbide, abrasives, hard minerals, sodium percarbonate, instant coffee, adipic acid, pelletised carbon black, flakes, chips
Advantages:
- Advantages of the Puls Pneu conveying method
- enables truck unloading over longer conveying distances
- enables truck unloading with conditioned conveying gas (dry air)
Comparison of all pneumatic conveying systems
| Negative pressureto bar (abs.) | Positive pressureto bar (abs.) | Particle size from ...to ... µm (mm) | Speed m/sec A. End. | Loading μ kg/Prod.kg/Gas | |
|---|---|---|---|---|---|
| Solids Fly Pneu | 0.5 | 2.5 | 0.0005–20 | Product 12– 36Air 15– 45 | up to approx. 10 |
| Solids Fluid Pneu | 0.2 | 4.0 | 0.01–1 | Product 3–15Air 5–20 | 15–30 |
| Solids Vacu Fill | 0.2 | - | 0.01–5 | Product 1–15Air 3– 20 | 15–30 |
| Solids Step Pneu | - | 6.0 | 1–10 | Product 0.5–10Air 1–15 | 20–40 |
| Solids Split Pneu | - | 4.0 | 0.001–1 | Product 3–15Air 5–20 | 15–40 |
| Solids Puls Pneu | - | 5.0 | 0.001–1 | Product 0.5–6Air 1–9 | 20–60 |
| Solids Vibro Puls Pneu | - | 5,0 | 0,0005–20 | Product 0.5–10Air 1–15 | 20–100 |
| Solids Vacu Dense | 0.2 | - | 0.001–5 | Product 0.5–10Air 2–15 | 20–40 |
| Solids Truck Discharge | - | 3.0 | 0.01–10 | Product 0.5–6Air 1–9 | 20–60 |
Bulk solid analysis
This is how we select the right pneumatic conveying method for you:The different bulk solid properties are an important decisive factor when it comes to selecting the right conveying method. For this, a comprehensive knowledge of the bulk solid properties is an absolute necessity. These properties are determined in a bulk solid analysis.
The bulk solids are considered according to their fluidisation behaviour and air retention capacity or according to their flowability and discharge behaviour. Other important factors include the general task and specific requirements, such as preservation of product properties, particle size, volume, bulk density, low-contamination abrasion behaviour, etc.
Bulk solid analysis
lime, PVC |
Good fluidisation, good air retention capacity Group A: fine and/or light |
solids Fly Pneu solids Fluid Pneu solids Vacu Fill Sand, bottom ash, granules |
Poor fluidisation, poor air retention capacity Group B: Grain size medium and/or heavy |
solids Fly Pneu solids Step Pneu solids Vacu Dense solids Truck discharge |
|---|---|---|---|---|
|
chalk, titanium- dioxide, metal oxides, milk powder |
Cohesive to very cohesive, no air retention capacity, rat holes Group C: fine and/or heavy |
solids Vibro Puls Pneu solids Split Pneu solids Vacu Dense | ||
|
sugar, nuts, salt, almonds, semolina, frozen vegetables, granules |
Crystalline to granular, no air retention capacity, no fluidisation Group D: coarse and/or heavy |
solids Step Pneu solids Puls Pneu solids Vacu Dense solids Truck discharge | ||
|
prepared mixes, glass batch, Dry plasters with aerosil, batch, blends |
Poor air retention capacity, fluidisation creates segregation Group C to D: fine and/or heavy, coarse and/or heavy |
solids Vibro Puls Pneu solids Vacu Dense solids Truck discharge | ||
|
moist sands, mixtures, centrifuge moist solids |
Poor air retention capacity, no fluidisation, mouldable correspondingly Group C: fine to coarse and moist |
solids Vibro pulse pneu spray granules, chips, instant products, perborate, tablets, percarbonate, pastilles, adipic acids |
sensitive products, agglomerates, no air retention capacity, no fluidisation Group B and D: Grain size medium to coarse and/or heavy |
solids Puls Pneu solids Vacu Dense solids Truck discharge |
|
Abrasive products |
All products from a hardness of approx. 4 according to Mohs Non-classifiable |
solids Split Pneu solids Puls Pneu solids Vacu Dense solids Truck discharge | ||
|
pieces of recycled materials, broken pieces |
no fluidisation, no air retention capacity According to group B to D |
solids Fly Pneu solids Vibro Puls Pneu |
Grouping according to Geldart and Jenike
For selecting a suitable process/system and components, first and foremost an analysis of the bulk solid(s) to be conveyed is required.
Geldart divides the bulk solids into groups A, B, C, D according to their fluidisation characteristics and air retention capacity, providing a rough classification with regard to conveying behaviour
- A: powders with a fine particle size and low density that fluidise well and have good air retention capacity
- B: medium particles of medium density, fluidisation possible with poor air retention capacity
- C: fine powders of a higher density, cohesive, difficult to fluidise with poor air retention capacity
- D: coarser particles with a higher density, fluidisation not possible, no air retention capacity
Jenike describes the flowability of bulk solids by the flow function coefficient (FFC), providing a rough classification with regard to discharge behaviour from containers. It makes the following distinctions:
- Free flow: 10 ≤ FFC < ∞
- Flow: 4 ≤ FFC < 10
- Cohesive: 2 ≤ FFC < 4
- Very cohesive: 1 ≤ FFC < 2
- No flow, hardening: FFC < 1
Unique plug conveying
Solids Puls PneuHosokawa Solids developed a complete process for pneumatic plug conveying as early as 1970. Thus far, more than 1000 systems for thousands of different products in every country of Europe as well as the USA, Japan and India have been designed and built according to this concept. It features an impulse valve for forming material plugs and a secondary line with so-called relay stations for maintaining and further transporting the material plugs without disintegrating them.
1 control cabinet 2 storage tank 3 inlet valve 4 pressure vessel 5 overfill protection & empty indicator 6 pressure sensor 7 special outlet 8 impulse valve 9 relay stations 10 special conveying elbow 11 compressed air supply 12 venting valves