Pneumatic Conveying Using Venturi Eductors

Venturi Eductors are commonly used for pneumatically conveying material particles in the dilute phase. This type of system creates two effects: the suction in the feed inlet and the positive pressure that pushes the particles into the conveying system. The eductor introduces a driving air from a source into a nozzle. This would eventually result in a vacuum in the suction feed that will draw the particles into the eductor. The particles are driven by the compressed air and passed through the diffuser,and finally discharged into the conveying system. 

Eductors are an efficient way of feeding particles like powders, flakes, abrasives, bulk solids, and other granular particulates. With this type of system, maintenance cost is greatly lessened through the elimination of the conventional rotary objects used in this application. Rotary valves do not perform well in conveying materials with very fine and abrasive textures and that is why venturi eductors work best for these applications.

Another advantage of this type of conveying method is that it eliminates the Blowback effect caused by using rotary airlocks/ rotary valves. Blowback may cause several problems in the system and these are the wear problems when conveying fine or abrasive particles, housekeeping problems, and explosion hazards. In addition to this, eductors also eliminate the harmful effects a rotary valve may cause a product, thereby minimizing the damage and degradation of the conveyed particles.

Industries that use Venturi Eductors in their conveying system:

This type of Pneumatic conveying system is used widely in almost all industries and these are:

Construction Supplies Industry

This industry makes use of venturi eductors to transport and convey gypsum, sawdust, phenolic resin, pumice powder, roofing aggregates, and cement.

Glass and Ceramics Industry 

Venturi eductors are the best way to transport the raw materials used to create glass and ceramics like glass frit, Mica powder, Silica Powder, sand, and ceramic dust.

Food Grade Processing Industry

Using eductors in transporting food is the best way to maintain the freshness and cleanliness of the particles being conveyed. Some examples of types of foods conveyed through a pneumatic system are breakfast cereals, rice, coffee beans, sugar, frozen peas, granulated seasonings, and other minor ingredients for food processing.

Metal Working Industry

The metal-working industry involves casting metals and during this process, foundry dust by-products are produced. The by-products are stored in the dust collectors and will then be conveyed out using venturi eductors.

Mining Industry

In this industry, using pneumatically conveyed systems is the most efficient and effective way of transporting the mined ores and by-products throughout the mining process such as mica, perlite, quartz, and talc. These types of conveyors are also reliable in transporting products that are not in conventional conditions (metal pellets that have a bulk density of up to 64 kN/ cubic meter and alloys that have a temperature that reaches 540 degrees celsius).

Polymers and Plastics Industry

Using venturi eductors in conveying plastic pellets from extruders are a great way to reduce and avoid the formation of undesired angel hairs and fines because eductors convey the plastic chips and particles without damaging their structure and finish.

Pollution Management industry

In industrial usage, venturi eductors are the devices they use to convey products such as activated carbons, Pulverised limestones, Hydrated lime, and Sodium Bicarbonate into the stacks and the ducts.

Power Generation and Combustion Industry

Venturi eductor pneumatic systems are used in the power plants where combustion is involved. These systems provide a great way of conveying in-process materials such as coal, coke, chopped tires, biomass and by-products such as the particles coming from the flue gases.

Key Takeaways…

Venturi Eductors in a pneumatic system is an efficient way of feeding particles like powders, flakes, abrasives, bulk solids, and other granular particles because of the great benefits of eliminating the need for recurring maintenance.

Author: John Hamlin