Dual-Tunnel Drying Ovens for Transformer Manufacturing: Advancing Efficiency in the Energy Sector

Dual-Tunnel Drying Ovens for Transformer Manufacturing: Advancing Efficiency in the Energy Sector

Consolidating its close relationship with this customer, NUTEC Bickley has begun construction of two large dual-tunnel drying ovens for one of the electric industry leaders operating across the Americas. These ovens – among the largest supplied to the energy solutions client – will join many ovens and furnaces for a variety of processes (drying, varnish curing, paint) ordered from NUTEC Bickley by them over the past 20 years.

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Drying Transformer Active Parts: Process Importance and Benefits

The ovens in this latest project will be used to dry the internal active parts of transformers, including coils, wiring, and internal insulation. Before these components move to assembly, sealing, and final packaging, it is critical to remove all moisture.

Proper drying:

• Increases insulation resistance
• Prevents failures
• Extends transformer service life
• Eliminates certain gases
• Enhances overall operational safety

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Long-Term Partnership and Project Significance

Arturo Arechavaleta, NUTEC Bickley’s VP of Metal Furnaces, said:

"Our customer for this significant contract places a great deal of emphasis on the quality, reliability and efficiency of the systems that it offers all around the world. We are extremely pleased to have been chosen once again as a key technology partner, a testament to the high-level performance of NUTEC Bickley design and manufacture. The fact that they have returned to us for a variety of installations over the past two decades speaks to a much-valued relationship that we look forward to extending over many more years."

Dual-Tunnel Oven Design and Operation

The semi-continuous ovens each have two tunnels arranged in a double-deck configuration. The lower tunnels will support a maximum load weight of 70,000kg (154,320lb), while the upper tunnels can support 40,800kg (89,950lb). They have been designed for the most effective and efficient drying of large transformer internal active parts.

The lower tunnels have setting dimensions of 2.9m (9.5ft) length by 2m (6.6ft) width by 2.8m (9.2ft) height, while the upper tunnels have setting dimensions of 2.37m (7.8ft) by 2m (6.6ft) by 2.3m (7.55ft). With just one heat zone, the ovens typically carry out the drying operation at a continuous 120°C (250°F), and they have a maximum capability of 200°C (390°F).

Combustion System and Indirect Heating Design

The combustion system is designed to use natural gas, with each oven equipped with a single indirect-fired burner. This configuration prevents combustion products from mixing with the process air, ensuring a clean and controlled drying environment for sensitive transformer components.

Airflow, Recirculation, and Temperature Uniformity

Each oven includes a centrifugal recirculation fan that delivers a high volume of airflow within the drying tunnels. This recirculation improves temperature uniformity and enhances heat transfer to the transformer active parts.

Internal Ducting and Air Distribution System

NUTEC Bickley proposed an internal duct and plenum system for the uniform distribution of air throughout the load volume. The purpose of this system is to provide vertical airflow directly to the transformer active parts on both load levels. In this way, the air will pass uniformly through the load and subsequently flow to the combustion chamber for recirculation.

Material Handling and Automation System

Parts are moved using a dedicated roller conveyor system with two independently controlled levels. The installation includes two transfer cars equipped with scissor lift tables and motorized rollers for efficient loading and unloading.

The entire system is controlled by an advanced PLC integrated with an HMI, featuring a user-friendly 12-inch touchscreen interface for operation and monitoring.

Safety and Compliance Standards

All elements of these dual-tunnel drying ovens are designed in accordance with NFPA 86, ensuring compliance with recognized U.S. safety standards for industrial ovens and furnaces.

Transforming the Energy Sector with Advanced Drying Technology

This project highlights NUTEC Bickley’s continued role as a trusted partner in the energy and transformer manufacturing sector, delivering large-scale drying solutions engineered for performance, safety, and reliability. With advanced airflow design, controlled heating, and fully integrated automation, these dual-tunnel drying ovens are built to meet the demanding requirements of modern transformer production.Companies seeking to improve drying efficiency, product quality, and process reliability are encouraged to explore how customized thermal solutions from NUTEC Bickley can support their operations.

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Let’s talk about your next project!

Arturo Arechavaleta – VP Metal Furnaces, NUTEC Bickley

Contact us to start the conversation.