A pneumatic conveying system in which the gas conveying speed is generally lowed than the minimum maintenance speed of the conveyed product, can be defined as Dense Phase or transfer of controlled slugs of dry powdered or granular materials through enclose convey lines.

This system differs from the Dilute Phase one in the following characteristics:

-         the product speed is lower than the maintenance speed;

-         the product pressure is typically higher than 1 bar;

-         efficient ratio between the material conveyed and the required air (product kg and air kg);

-         lower product speed when conveying.

- The Dense Phase Conveying System moves the product at a relatively slow speed, reducing the risks of product degradation and the abrasion of pipe-lines, bends and diverters.

- Dense Phase Pressure conveying reduce the risks of product degradation and the air consumption, giving an efficient ratio between the material conveyed and the needed air (product kg and air kg).

There exist three type of Pneumatic Conveying in Dense Phase:

- Pneumatic Conveying with a Transporter

- “Slow Flow” with Rotary Airlock Pneumatic Conveying