Pipe screw conveyors with ATEX approval

Pipe screw conveyors with ATEX approval designed and manufactured by BEMA.

Working in environments with combustible dust requires absolute certainty that every component in the production line meets strict ATEX regulations. This case highlights how BEMA A/S engineered and delivered three tubular pipe screw conveyors with full ATEX approval for transporting wooden fibres in a classified zone. The project demonstrates how a tailored mechanical design, precise zone compliance and complete documentation can ensure safe, efficient and reliable material handling in potentially explosive atmospheres.

A challenging environment with strict ATEX requirements

The customer needed a transport solution capable of moving large volumes of wooden fibres inside an ATEX‑classified production area. The inside of the screw conveyors was defined as zone 20, meaning continuous presence of combustible dust, while the surrounding area was classified as zone 3D, where dust is only present occasionally. This combination places high demands on both construction and documentation. The customer therefore required a partner with deep ATEX expertise who could design a system that complied precisely with the defined zones—without unnecessary complexity or cost.

A tailored solution: Three tubular screw conveyors

BEMA designed and manufactured three pipe screw conveyors specifically for this application. Tubular conveyors are ideal for light, fibrous materials because the closed design prevents material from falling back, ensuring a higher and more stable transport capacity compared to trough or U‑shaped conveyors.

Each conveyor was engineered to match the customer’s exact ATEX zone classification. BEMA’s approach focuses on designing strictly to the required safety level—no more, no less—ensuring compliance while maintaining mechanical simplicity and operational reliability.

Key elements of the solution included:

• Mechanical design adapted to zone 20 internally and zone 3D externally
• ATEX marking on conveyors and gearmotors where required
• Full documentation package prepared for the customer
• Option for submission to a notified body if external approval was needed

Complete documentation for full compliance

A major part of any ATEX project is the documentation. BEMA handled the entire process, ensuring that the customer received all required material to demonstrate compliance. The documentation package included:

• Machine drawings referencing the defined ATEX zones
• ATEX marking and technical specifications
• Declaration of conformity
• Approval certificates from a notified body when applicable This thorough documentation gives customers confidence that every requirement has been met and that the installation is fully traceable and compliant.

Proven ATEX performance

The delivered solution is approved for ATEX zone 1D inside the conveyor and 3D outside . The conveyors now ensure stable, dust‑tight and efficient transport of wooden fibres, even under demanding conditions. The closed pipe design minimises dust emissions, reduces risk and supports a safe working environment.

The customer benefits from:

• A fully ATEX‑approved transport system
• High transport capacity with minimal material fallback
• Reliable operation in a dust‑laden environment
• Complete documentation for regulatory compliance
• A solution engineered precisely to the required zone classification

A safe and efficient choice for ATEX environments

This case illustrates how BEMA combines mechanical expertise with regulatory insight to deliver safe, efficient and compliant screw conveyor solutions for ATEX‑classified areas. With a clear understanding of zone definitions and a strong focus on documentation, BEMA ensures that customers receive a solution that meets all requirements—without unnecessary additions or complications.

See another screw conveyor from BEMA with ATEX approval

Frequently Asked Questions About ATEX‑Approved Pipe Screw Conveyors

What ATEX zones apply to pipe screw conveyors?

The inside of the conveyor is typically classified as zone 20, where combustible dust is continuously present, while the surrounding area is often zone 3D, where dust only occurs occasionally. The exact classification must always be defined by the end customer before design work begins.

Who is responsible for determining the correct ATEX zone?

The end customer is responsible for defining the ATEX zone classification—both inside the screw conveyor and in the surrounding environment. Once the zones are defined, BEMA designs the conveyor to meet those exact requirements without adding unnecessary components.

What documentation is included with an ATEX‑approved screw conveyor?

BEMA provides a complete documentation package, including machine drawings with zone references, ATEX marking on the conveyor and gearmotor when required, a declaration of conformity, and approval certificates from a notified body if used.

What are the advantages of using tubular screw conveyors in ATEX zones?

Tubular (pipe) screw conveyors prevent material from falling back, enabling higher transport capacity and improved dust control. Their closed design is especially beneficial in ATEX environments where dust containment and safe operation are critical.