Dilute phase pneumatic conveying

Dilute phase pneumatic conveying systems for bulk materials handling, also called lean phase pneumatic conveying systems, can be designed in different ways: pressure, vacuum or a combination vacuum/pressure. Below are the main characteristics of these systems:

Some applications of dilute phase pneumatic conveying

Dilute phase 1

Dilute phase 2

Dilute phase 3

Details of a vacuum lean phase pneumatic conveying system.

Vacuum System

Vacuum conveying systems are mainly used, but not limited to, for the conveying of bulk materials from multiple sources to a single destination. It is suitable for non-hygroscopic material or for substances that do not undergo chemical-physical changes when exposed to heat (e.g., waxes)

Suitable to convey granules and powders.

A dosing device (such as rotary valve or dosing screw) can be used at the beginning of the line.
In case of flowable products, it is possible to use a sampling lance.
Vacuum conveying is suitable for medium-low throughputs (<4-5 T/h) and medium distances <60÷80m.

Pressure System

Pressure conveying systems are used to convey bulk materials from one source to multiple destinations and is ideal when the material is exposed to high temperatures (e.g., ashes). This system is not recommended to handle toxic or hazardous substances as, in the event of accidental breakage of the pipes, the product could be released into the environment.

Suitable for long conveying paths.

Pressure systems are also suitable to convey granules and powders. The material is loaded into the line by using a sealed organ (rotary valve).

Pressure systems are suitable for medium-high flow rates (up to 20 t/h) and long distances (up to 150-200m).

Details of a vacuum-pressure dilute phase pneumatic conveying system.

Vacuum / Pressure Combination

This system is a combination of the previous of vacuum and pressure systems in a single unit.

In vacuum/pressure conveying systems the transport is carried out by a combination of suction and pushing.

It is often used to convey flour in plants for the production of pasta or similar, when the product needs to be sieved at an intermediate point.

What is lean phase conveying?

Descrizione

In dilute phase pneumatic conveying systems the particles are carried suspended in the air through an enclosed pipeline.

Typical values in lean phase conveying are:

pressure

ΔP: from + 0,2 to +0,8 bar for pressure systems
from -0,2 to -0,5bar for vacuum systems

conveying speed: between 18 and 30 m/s (depending on flow rate and material characteristics)
mixing ratio: it is defined as the ratio between the product and the air (kg product/ kg air). This ratio should not exceed 8÷9, however it is advised to keep it below 5÷6.
throughput: approximately from 1 to 20 T/h

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Applications of dilute phase pneumatic conveying

Dilute phase pneumatic conveying

Side channel blowers or lobe compressors are commonly used in dilute phase pneumatic transport and, in some instances, such as light products and low flow rates, fans are usually used too.

Dilute phase systems are well suited to convey powders and granules in all productive sectors, from food industry to chemical, plastic and rubber.

Find out how to leverage lean phase conveying

Take a look at some fields of applications

Advantages

Flexibility

Simple installation

Compact dimensions

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