Solids Conveying


Solids Conveying

At GMdix Process Engineering, we are experts in the development of complete systems for bulk solids handling. Our services include the design and assembly of industrial installations, as well as the manufacturing of components and equipment for the pneumatic and mechanical conveying of solids.

Types of solids conveying

The solids conveying presents certain difficulties given the great variety of materials. These may be hard, soft, resistant, wet, rubbery, fragile, plastic, adhesive, powder, elastic, etc., so they must be adapted to the different handling and conveying requirements of each.


Pneumatic Conveying

Pneumatic conveying uses an air current to move powder or grainy products. Any type of bulk solids with a granulometry of up to approximately 70 mm may be conveyed.
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Mechanical Conveying

This is the mechanical conveying of a solid product to different points in an industrial facility. The mechanical equipment used to convey solids will depend on the product to be conveyed, the layout, and the distance.
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Pneumatic conveying of bulk solid materials


The objective of the pneumatic conveying of solids is to move bulk solid materials from one point to another by means of a gas current at either positive or negative pressure via piping. Ideal materials for this type of conveying system are dry, fine, bulk materials from microns up to particles of 70 mm or larger. We can convey solids both horizontally and vertically and from a few meters to a maximum of approximately 500 m.

There are four elements that make up a pneumatic conveying system:

Pressure generating element

This supplies sufficient mechanical energy to the gas to move the solid. Possible generating elements include fans, emitters, blowers, and compressors.

Conveying line

This refers to the set of pipes, elbows, branches, valves, etc., required to convey the solid from its loading point to its destination. The dimensions and characteristics of these elements will depend on the type of solid, gas flow, layout of the origin and destination points, and the conveying pressure. In the same way, the internal characteristics of the pipes must be considered, which will depend on the abrasion of the product.

Solids discharging devices

This is an important element that requires special attention. Its design depends on the type of solid, flow rate, production, and required pressure. Among the possible elements are rotary valves, airslides, venturi tubes, timing screws, etc. These elements are responsible for loading the solid into the conveying line.

Solid-gas separator element

This separates any solid gas particles in suspension. The elements used for this may be any type of cyclone separator and filter.

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Types of pneumatic conveying systems


Pneumatic conveying systems have two sorting mechanisms:

1.- By the concentration of the solid inside the conveying pipe:

– Dilute phase

– Dense phase

2.- By the source of pressure differential generation:

– Vacuum

– Discharge

Each type of system has different applications as explained below.

Dense Phase Pneumatic Conveying

Dense Phase Pneumatic Conveying

The volume of air is significantly lower, the solid is conveyed by discharge creating packages, therefore a higher pressure and a significantly lower volume of gas are required. Energy consumption is lower, due to the greater use of the energy transmitted to the gas. The conveying speed is lower, therefore producing less wear. When the solid is abrasive, for example, this is the most recommended mode.


It may be subdivided into fluidised dense phase or packages. At GMdix Process Engineering, we are able to execute each according to the characteristics of the project and the client’s requirements.

Fluidised Dense Phase Pneumatic Conveying

Dense phase pneumatic conveying by packages

Dilute Phase Pneumatic Conveying

Dilute Phase Pneumatic Conveying

In dilute phase pneumatic conveying, the particles in suspension move through the pipe at high speed with a large amount of low-pressure air. Suitable for conveying low abrasive products.

fase diluida

In this type of pneumatic conveying system, the material is conveyed in suspension inside the pipe. The particles are uniformly distributed throughout the cross-section of the pipe (homogeneous flow). The concentration of solids is relatively low (less than 10 kgs of solids per kg of gas), and the conveying speed is relatively high.

Dilute phase pneumatic conveying is divided into vacuum and discharge.

Transporte neumático en fase diluida en aspiración

Los sistemas neumático en fase diluida por presión negativa o en aspiración son ventajosos cuando necesitamos alimentar un elemento desde diferentes puntos. Se realiza mediante un soplante o bomba de vacío donde el producto es aspirado junto al gas hasta el punto o puntos de destino.

Transporte neumático en fase diluida por impulsión

En el transporte neumático en fase diluida por impulsión o por presión positiva una fuente de generación de aire a presión crea una corriente de gas en la cual estará disuelto el sólido logrando su movimiento desde el punto de origen hasta el punto de destino.

Advantages and disadvantages of pneumatic conveying


Dust-free conveying of a variety of products
Layout flexibility: material may be conveyed vertically and horizontally by adding piping elbows
Possibility of conveying a multitude of products
Ease of automation and control
Low maintenance and low number of moving parts
Ease of conveying, collection, and distribution to different points
Higher energy consumption than other solutions
Wear and abrasion of the equipment depending on the product to be conveyed
Improper design can lead to particle degradation
Limited distance
Due to the complex flow phenomena that takes place, it could become complicated to design, operate, and maintain the systems

Industrial equipment for solids


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Mechanical conveying systems


Mechanical conveying is ideal for feeding or discharging powder or grain products. The materials especially suitable for this type of conveying are fragile, humid, pasty, and susceptible to caking. We manufacture equipment for mechanical conveying, such as through screws and conveyor belts.

What are the advantages of mechanical conveying of solids?

Reduction of installation costs
Free of ambient air contamination as it uses no external air supply in its operation
Large flows
No breakdown of the mixture
Versatile and easily adaptable
Careful conveying Suitable for fragile materials
Minimum space required
Low energy consumption
Minimal maintenance

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