(by Gerrard & Associates)

Pneumatic conveying is an efficient and cost effective solution for conveying dry bulk material.  There are three types of pneumatic conveying: Dense Phase, Semi-Dense Phase, and Dilute Phase.  The type of conveying is dependent on the material being conveyed.

Abrasive and very fragile material will require a different type of system versus a material that non-abrasive and non-fragile.  Pneumatic systems also cost significantly less to maintain when compared to a traditional mechanical system.  The three types of pneumatic conveying are further defined below.  For more details, please visit  www.cyclonaire.com or contact Gerrard and Associates.

1. Dense Phase Pneumatic Conveying

For low- or high-rate transfer of abrasive or friable material, dense phase conveying is the optimum solution.

Dense phase pneumatic conveying is a relatively low-speed system where the material is not suspended in the air stream. The low velocity of dense phase means less wear and tear on both the system and the materials being conveyed. The velocity is typically set between 400 ft./min. and 1,000 ft./min., though there are several forms of dense conveying.

Our pneumatic conveying experts can ascertain the correct conveyance phase for your material in order to design a custom system that successfully meets your unique material handling requirements. We offer models with vacuum or gravity load, featuring top or bottom discharge to match your application and materials.

Dense Phase is Ideal with:

  • Very fragile materials and mixtures, as the low speed and lower air volumes prevent materials from breaking down.
  • Best for low- or high-rate transfer of abrasive or friable materials, as the slow convey speed reduces abrasion of convey lines.
  • Slightly hygroscopic materials, without requiring the introduction of air drying equipment because air quantities required for dense phase are significantly lower than that of semi-dense and dilute.
  • Examples: Sand, sugar, carbon black prill

2. Semi-Dense Pneumatic Conveying

A semi-dense phase conveying system is the optimum solution for medium-rate transfer of aeratable abrasive or friable materials.

As an intermediary step between dense and dilute phases, the semi-dense phase conveys materials using a medium velocity. Only a portion of materials are suspended in the air stream. Typically set between 1,500 ft./min. and 3,500 ft./min., the velocity ranks higher than dense phase and lower than dilute.

Offering less abrasive wear and particle degradation, exclusive Cyclonaire components can work together with a semi-dense system to ensure proper conveyance of all materials.

Semi-Dense is Ideal with:

  • Products in an aeratable state
  • Abrasive or friable materials
  • Examples: cement, fly ash

3. Dilute Phase Pneumatic Conveying

Dilute phase pneumatic conveying is well suited for continuous conveying when degradation and abrasive wear are not issues.

Dilute phase is a high-velocity system where the conveyed material is continuously suspended in the air as it is blown or sucked through the pipeline. Material does not accumulate at the bottom of the convey line at any point. To maintain this suspension, air velocity must be kept, most often, between 5,000 ft./min. and 8,000 ft./min.

Because in-house design and off-the-shelf equipment may not always provide the best answer, we offer custom engineering at competitive prices. We work closely with each customer to learn about specific requirements and restrictions and design a system that is custom made.

Dilute Phase is Ideal with:

  • Non-abrasive and non-fragile materials with a light density.
  • Certain batching systems
  • Examples: flour, cornstarch