Zero-Contamination Pneumatic Transport with Air Compression


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The process of using compressed air to transport bulk materials is called pneumatic conveyance. It’s a process regularly used in an array of industries, from food and steelmaking to recycling.

In industries where minimizing contamination of products is critical, the pneumatic conveyance process allows handlers to benefit from extremely efficient transport of dry powders and granular solids. As a result, the performance of the air compressor that powers the pneumatic transport systems is crucial.

This article will take a look at a range of key applications for pneumatic conveyance systems, exploring how efficiency is improved and contamination reduced in the next-generation compressor technologies.

Pneumatic conveyance was initially developed for agricultural use as an alternative to grain augers. Grain augers worked on a similar principle to the Archimedes screw. Pneumatic conveyance became increasingly common in agriculture after its initial application in discharging grain from cargo ships, because it offered increased flexibility, reduced safety risks and significantly decreased dust in the grain intake area compared to grain augers.1

Then, the benefits of pneumatically transporting dry materials in bulk were modified by other industries, and were used in almost every process requiring flakes, pellets, powders or granules to be transported.

One such industry is the metal industry, which has adopted widespread use of pneumatic conveyance. This is particularly common in iron and steelmaking. For example, using compressed air systems to inject coal directly into the blast furnace demonstrates a reduction in the cost of drying and grinding processes.

Pneumatic injection of flux can also be utilized to reduce imperfections in continuous metal casting.2 European Integrated Pollution Prevention and Control (IPPC) recommend pneumatic transport of all powdered materials to reduce handling and contamination of products.3

Pneumatic conveyance has also found major application in the food industry. Here, compressed air is used to transport dried foodstuffs efficiently and reliably. The Milser flour mill in Nordrhein-Westfalen, Germany utilizes seven positive displacement blowers 24 hours a day to transport large amounts of flour without contamination.

One of pneumatic transport’s main benefits when compared to other handling methods is found in the very low contamination rates, which is a vital risk to keep under control in the food, pharmaceuticals, and a number of engineering industries. However, the performance of the air compressor does influence the amount of contamination able to occur in dry goods being transported sealed tubes.

Contamination is often a problem with air-compressing machines that use parts lubricated with oil. In such cases, the risk of lubrication coming into contact with the transported goods often stops them from being suitable for the low-contamination applications previously discussed.

Bulk material in these systems is not only at risk of being contaminated by oil, but oil contamination can also cause damage to the rest of the compressed air system, which may even result in entire system failure.4

Achieving 100% Product Purity with ATEX-Certified Pneumatic Conveyance

Aerzen has set a new standard for purity with its range of air compression technology for pneumatic conveyance systems. This line of technology is suitable for use in the most demanding industries, from food, cosmetics, and pharmaceuticals, to medical technology.

Aerzen’s positive displacement blowers, rotary lobe compressors, and screw compressors are all certified according to ISO 8573-1: 2010 Part 1: Contaminants and purity class, ISO 8573-2: 2007 Part 2: Test methods for aerosol oil content, and ISO 8573-5: 2001 Part 5: Test methods for oil vapor and organic solvent content; ensuring the total purity of the operating air.

Additionally, Aerzen’s air compressors, hybrids, and blowers provide unmatched quietness and safety standards due to their ATEX-certified absorption-free discharge technology. In typical pneumatic conveyance systems, the discharge silencer can be vulnerable to problems.

These discharge silencers are often lined with absorption material, which is vulnerable to wear due in the main to pulsations created by the compressor or blower, the high air temperatures and abrasion from contact with air particles weakening the insulation material. As a result, absorption material is blown out of the discharge silencer, which causes the conveying air to become contaminated and the sound absorption capacities are greatly decreased.

Aerzen is dedicated to developing an entirely new, absorption-free silencer technology, which not only successfully insulates sound and eradicates contamination of discharged material, but also provides a reliably high level of efficiency over the machine’s entire lifetime.

This is particularly advantageous for ATEX applications, as the reactive silencer from AERZEN operates as a spark arrestor, eliminating the risk of explosions as sparks cannot pass the compressor or blower. Aerzen’s Delta Blower, Delta Screw and Delta Hybrid have been specially developed for ATEX categories 2 and 3 for internal and external dust and gas zones (1,21,2,22), in accordance with European Machinery Directive 2014/34/EU. Explosion protection for systems in accordance with ATEX directive 137 (1999/9/29/EC) has also been taken into account to offer a preeminent, safe pneumatic conveyance solution.

The Delta Blower, Delta Hybrid and Delta Screw from Aerzen provide a universal range of solutions for all pneumatic transport applications.5–7 Every solution provides extraordinary energy efficiency, enabling reduced operating costs, no absorption material in silencers, zone-separate filters and spark arrestor function suitable for ATEX solutions, operational safety due to various monitoring systems and operation-friendly, low-maintenance design. Additionally, Aerzen’s accessories can be customized and tailored to the most demanding applications.

References and Further Reading

  1. Hellevang, K. J. Pneumatic Grain Conveyors. (1985).
  2. Weiser, R., Braune, I. & Matthes, P. Control Blast Furnace Pulverized Coal Injection to Increase PCI Rates.
  3. Integrated Pollution Prevention and Control (IPPC) Best Available Techniques Reference Document on the Production of Iron and Steel. (2001).
  5. Blower unit Delta Blower Generation 5 - AERZEN. Available at: (Accessed: 25th October 2019)
  6. Screw compressor Delta with belt drive - AERZEN. Available at: (Accessed: 25th October 2019)
  7. Rotary Lobe Compressors Delta Hybrid - AERZEN. Available at: (Accessed: 25th October 2019)

This information has been sourced, reviewed and adapted from materials provided by Aerzener Maschinenfabrik GmbH.

For more information on this source, please visit Aerzener Maschinenfabrik GmbH.


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