Innovators in pneumatic conveying & bulk materials handling
Call : +44 (0)1858 410737

Closed Loop Conveying

Aptech’s own Closed Loop Conveying (CLC) System is the answer to many customers’ problems. It is the ideal method of pneumatically conveying hygroscopic, sterile, perishable and hazardous products such as sugar, starch, potato / milk powder and oxidising powders where product exposure to unconditioned gas can cause product degradation and introduce material handling problems.

Every system is designed specifically for each customer’s application. They are based on proven designs and typically consist of an enclosed loop of pipework limiting conveying gas changes within the system.

For a dry air CLC, a small dehumidifier ‘tops up’ air lost or deliberately purged from the closed system. This design allows economically sized dehumidifiers to be used for large systems with a large air/gas conveying volume.

As a result, the conveying air/gas is of a consistent quality and limits introduction of atmospheric air with its varying levels of moisture and contaminants. The result is product which remains sufficiently dry to inhibit mould growth or limit reaction with air and promote consistently good flow characteristics.

Storing and conveying in dried air is proven to solve handling problems, vastly reduces downtime and makes economic sense. It avoids caking, contamination, spoiling, and loss of product.

The sealed circuit can be designed to a products explosion pressure rating satisfying the explosion risk. This allows the safe handling of explosive product without the need for explosion panels which often do not fit in with a factory’s layout, position or design.

The different CLC system advantages are summarised below:

Sealed System

  • No airborne contaminants
  • Contained emissions
  • Clean enclosed method of conveying
  • Re-circulating gas = Economic Dry Air Conveying
  • Economic inert Gas Conveying
  • Multiple destinations & single common filter

Nitrogen / Inert Gas Conveying

  • Hazardous products transported safely
  • Explosion panels and venting eliminated
  • Economic conveying by recirculation – minimal gas usage

Dry Air Conveying

  • No caking/agglomerating
  • Microbiological growth inhibited – ideal for food products
  • Product stays in good condition dry & free flowing
  • Reduced maintenance & cleaning
  • No condensation or need to lag/insulate pipes
  • Improved filter performance
  • Sterile Air Conveying
  • HEPA filtered air is introduced to the system to ensure biological contamination is eliminated.
  • We have designed systems with the capability of being 100% gas sterilised and featuring ASME BPE designs



Pressure Conveying System - pneumatic conveying system

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Aptech (Powder Systems) Ltd
Unit 1 Sutton Court, Bath Street
Market Harborough, Leics, LE16 9EQ
Phone: +44 (0)1858 410737
Fax: +44 (0)1858 434273



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