Pneumatic Conveying Systems & Regimes

Here at STB Engineering, we are a specialist pneumatic conveying systems manufacturer with over 50 years’ experience in all types of powder conveying systems. We benefit from our own in-house design facility and test house in which to develop our systems. We aim to be the leading experts in conveying technology, implementing new and innovative solutions at the forefront of our field.

We were pioneers of the Dense Phase conveying system in the early 1970s before developing our Pulse Phase and Dilute Phase conveying technology. Our vacuum systems have proven particularly popular in the plastics and PVC industries and we have also developed expertise in supplying to other sectors such as the food, pharmaceutical, chemical and mineral industries. With our long history of experience and innovation, you can rest assured that our knowledge of powder conveying systems is second to none.

You can find out below about the unique qualities of each conveying system by watching the videos below and reading the individual pages. If you have a question about our conveying systems, a work proposition or would just like to say hello, please don’t hesitate to get in touch with us by filling out our contact form. We would be happy to respond to any query you may have and help you find the right system for your company.

We specialise in five types of pneumatic transfer system which we can tailor to your individual requirements.


For most products in powder, flake or granular form. Particles are fully suspended in the air stream. Positive pressure – blowing system, negative pressure – vacuum system.

Speed & Pressure:

Speed: 18 – 35 m/s
Pressure: Up to 1 bar
Vacuum: Up to 0.5 bar


Dilute phase pneumatic conveying, sometimes also referred to as lean phase or suspension flow, is a mode of conveying where the material is kept in suspension in the air stream of the pipeline it is being conveyed in. This mode of conveying can be in either in a positive pressure system (blowing system) or a negative pressure system (vacuum system). The air stream must maintain a velocity high enough to suspend the product particles throughout the length of the blowing system or vacuum system. The minimum value of the conveying line air velocity to suspend a particle in the air stream is known as the “Saltation Velocity” and can be easily determined and tested for through pneumatic conveying trials. If the air velocity falls below this value the particles will drop out of the air stream and have a tendency to settle in the bottom of the conveying pipe.

This type of blowing or vacuum system is the most common and elementary type of pneumatic conveying system used around the world today.

These type of systems comprise:

  • A motive air force – a blower/fan or vacuum pump/ exhauster that delivers a flow of air to the pipeline
  • A feed device that entrains the product into the conveying air stream.
  • A filter or air separator / cyclone to remove the product from the air stream at the receiving end /collection hopper.

Dilute phase pneumatic conveying systems normally operate at positive or negative pressures up to 1.0 barg and have a low product to air ratio, which is usually up to a maximum of 15:1 with conveying velocities from 15 to 35m/s.

Designing such a system firstly requires specific product knowledge gained through conveying trial data and then requires a series of complex calculations to size the system to determine: the pipe diameter; conveying air volume; conveying line pressure; and size the blower / vacuum pump, feed device and filters for the given conveying line duty and configuration.

For any of the these types of dilute phase conveying systems, it is possible to have complex systems that can convey to any one of multiple delivery points through the use of diverter valves or collect product from multiple collection points. It is also possible to design the systems in a form of a closed loop conveying system limiting the introduction of atmospheric air and providing containment, or introduction of dried air for hygroscopic products, or, an inert conveying gas such as Nitrogen where there is an explosion risk.

Pneumatic Conveying Dilute Phase STB Engineering

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STB’s wealth of knowledge, coupled with over 50 years bulk materials handling experience, ensures technically assured results and performance time after time.
STB Conveying Systems
STB Pneumatic Conveying Systems Manufacturer
STB Pneumatic Conveying Systems Manufacturer
STB Pneumatic Conveying Systems Specialists
STB Pneumatic Conveying Systems Specialists
Pneumatic Conveying Regimes STB Engineering
Pneumatic Conveying Regimes STB Engineering
Pharmaceuticals and High Care Conveying Solutions STB
Pharmaceuticals and High Care Conveying Solutions STB
Negative Pressure Conveying System STB
Negative Pressure Conveying System STB