There are two main types of pneumatic conveying systems to choose from: lean phase and dense phase. Each is used for different applications and includes different functions.
The most commonly used pneumatic conveying system is a lean phase system used for granules and powders. There are two subcategories extending from lean phase systems:
Dilute Phase
Dilute phase conveying systems use velocities of greater than 17-18 m/s with lower vacuum or conveying pressure that falls below 0.1 barg. In dilute phase conveying systems, material particles are fully suspended within the air or gas stream while the solid’s loading ratio is significantly lower.
This type of system is ideal for conveying non-abrasive materials with low bulk density. Most systems would use side channel blowers or fans to move the product along the pipelines.
Common applications for dilute phase systems include:
Medium Phase
In medium phase pneumatic conveying systems, the gas or air velocity typically exceeds 17-18 m/s with a vacuum or pressure of as much as 0.35 barg.
Particles traveling through the pipelines remain suspended throughout, with a low concentration or solids loading ratio. Exhausters and roots blowers are often used to push air or other gas through the system.
If you want to move sensitive or fragile products, dense phase conveying systems are ideal.
You can use these systems to handle and transfer products at lower velocities, which helps prevent impact damage to the product. Dense phase systems use pulses of air to push the product through, followed by another pulse of both the air and product.
Unlike lean phase systems, dense phase systems require more precise calculations for designs and proper timing. The overall density, size of the particles, and the run or length will help determine the ratio of air to product when using these systems.
Some common applications for dense phase systems include:
Pharmaceutical
Minerals
Chemical
Plastics
Food
Petrochemical