Pneumatic conveyors use the pressure variations and gas flows like nitrogen or air while transporting dry materials. This pressure variation can be obtained by decreasing or increasing the pressures at the both ends. Also a blower can be used to provide the flow of fine powder.
For pneumatic conveyors push systems are named as positive pressure systems and pull systems are named as negative pressure systems. Materials are pushed from one side to another or from inlet to outlets by positive pressure systems and they are pulled from inlet to one outlet by negative pressure systems.
When pneumatic conveyors are compared to other types, they consist of fewer parts. They are suitable to utilize for dry materials like cement powder, sugar, wheat, sand etc.
Pneumatic conveyors have lower investment cost when compared to other types of conveyors. But if blower and vacuum usage is needed, this situation causes less efficiency and more energy consumption.
There are three types of pneumatic conveyors which are based on the material type will be moved;
- Dilute phase pneumatic conveyors
- Dense phase pneumatic conveyors
- Semi-dense phase pneumatic conveyors
Also while choosing the type of a pneumatic conveyor, material type affects some other criterias about system and process like;
- Flow rate, pipe design and distance
- Filters, fans and vents
- Control system