Pneumatic or Mechanical Conveyor?
Could You Benefit From a Pneumatic Conveyor System?
Pneumatic systems convey numerous materials quickly and efficiently - even materials once thought relegated to mechanical conveyors alone. The enclosed design of pneumatic systems
better protects the environment, workers and even the material itself
. But, h
ow do you determine if a pneumatic conveyor system is optimal for your application?
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Plant Transfer Convey Lines for Plastic Pellets to an Extruding Process for Wire Coating. Photo courtesy of United States Systems |
Pneumatic conveying systems transfer dry materials using either negative conditions (vacuum) or positive conditions (pressure). These systems require a blower package, a material feed device, a convey line and a solid-gas separation system.
Examples of mechanical conveying systems are screw conveyors, belt conveyors, rollers, bucket elevators and chain elevators. All require multiple moving and working parts. Mechanical conveyors can be opened or closed to the atmosphere whereas pneumatic systems convey material within a fully enclosed line.
One factor differentiating the two systems involves the distance of the material being conveyed. For short distances, a mechanical conveyor is more practical. For long distances with many changes of direction and/or elevation, a pneumatic conveyor excels.
Product Characteristics
When choosing between a pneumatic or mechanical conveyor, consider the flow characteristics and handling properties of the bulk solid to be conveyed:
- Abrasiveness
- Explosivity
- Friability
- Fluidizable
- Bulk density
- Particle size
- Temperature sensitivity
- Hygroscopic
- Ease of Flow
- Moist, Sticky or Packable
- Cross Contamination Issues
Pneumatic conveyor systems work best with fine, fluidizable dry powders which allow the material to be aerated and pumped through a convey line. Certain types of granular and pelletized material are also good candidates.
Heavy granular materials, including moist, doughy and packable materials, are best conveyed mechanically. Materials containing a variety of particle sizes are usually transferred using mechanical convey systems.
Here are some materials commonly conveyed with each system.
Pneumatic Conveying System |
Mechanical Conveying System |
Plastic (pellets, powders) |
Whole grains |
Cement |
Crushed Rock |
Polymers |
Gravel |
Lime |
Wet Sand |
Wheat Flour |
Large Food Particles |
Starch |
High Fat Materials |
Sugar |
Combustible Bulk Solids |
If a pneumatic conveyor system is right for your application, the benefits are many:
- Minimize floor space
- Ease of routing
- Eliminate spillage
- Prevent product contamination
- Employee Safety
- Eliminate Dust
- Ease of expansion
- Low maintenance
- Ease of automation and control
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