Roller hearth furnaces for annealing of copper and copper based alloys
Roller Hearth Furnaces
OTTO JUNKER is the leading supplier of continuous roller hearth annealing furnace lines for the heat treatment of copper and copper based alloys under protective atmosphere. Many of the world's major and well-known manufacturers are customers of OTTO JUNKER. OTTO JUNKER roller hearth furnaces operate on the proven principle of high convection.
The high-convection principle provides the following advantages:
- No high temperature head required (just a few Kelvin above product temperature)
- Zero risk of overheating
- Uniform heat transfer to the product
- Identical mechanical and physical properties
OTTO JUNKER offer two different types of roller hearth furnaces:
- Jet-heating type
- Mass-flow type
Design options
- Direct or indirect heating
- Indexing or continuous operation
- Open or protective atmosphere (typically N2 or up to 100 % H2)
- Optional vacuum chamber
- Gas fired or electrically heated
Jet-Heating
The Jet-heating furnace type is characterized by an extremely high air velocity which makes for an even more intense heat transfer. It is therefore particularly suitable for the heat treatment of thin or single-layer material.
This technique requires no high temperature heads to provide good heating. The uniform furnace chamber temperature ensures a highly even temperature distribution throughout the charge.
Mass-Flow
Mass-Flow furnaces rely on a "soft" high-convection process and are particularly well suited for multi-layer products (LWC coils and material to be annealed in bundled form). The proven space-saving configuration is the stack furnace in which multiple loads are annealed while stacked one above the other. The main characteristics of a mass-flow furnace, apart from its high atmosphere circulation rate and the resulting intense heat transfer, are the defined flow pattern and a uniform furnace chamber temperature which exceeds the material temperature by just a few Kelvin. In addition, stack furnaces are noted for their short build and ease of access.
Heating may be performed either directly or indirectly, depending on the application case. OTTO JUNKER stands for the use of highly efficient burners featuring waste heat recovery for preheating of combustion air.
For a cost-efficient heat treatment of copper under a protective gas atmosphere, both furnace types can be equipped with vacuum chambers.
CTP - Copper Tube Purging System
Most mass-flow furnaces supplied by OTTO JUNKER are equipped with our Copper Tube Purging System (CTP).
This OTTO JUNKER tube purging technology ensures clean, high-quality copper tubes by flushing out the oil vapours that will typically form inside tubular material during the heating process.
As a result, carbon deposits on the interior surfaces of the tube will be reduced significantly. Studies have shown that with an OTTO JUNKER tube purging system, much less carbon and oil residue will usually remain present on interior tube surfaces when compared to a system without protective gas purging. Even the very exacting requirements placed on copper tubes for air conditioning equipment can thus be fulfilled.
Automatic handling systems
In addition, automatic handling systems are available for each furnace version. These offer the following advantages:
- Available for each furnace version
- fewer manual interventions, reducing the risk of damaging the coils
- complete integration into existing equipment is possible
- full integration into the process technology is supported as well
- automation can be introduced gradually
- entirely unattended operation – from coil production to packaging – is a realistic option
The payback period will typically amount to only 2 years.
