The compact furnaces of the DH product line are optimally suited for continuous processes on a small floor space. They are designed for preheating processes such as the preheating of metal parts for forging. Charging and discharging can, be done at one position – either by a person or fully automatic. The hearth rotates in pre-set segments individually reconciled with the workpart geometry. The rotational speed and rotational intervals can be defined by the control system or by manual switching. The rotary hearth furnaces are specifically designed for the required throughput and charge dimensions. They are heated electrically or alternativelly gas-fired by means of powerfull gas burners. Subject to the temperature range these furnaces are equipped with or without air circulation.

• Tmax 1100  °C, 1200  °C or 1300  °C without air circulation
• Tmax 260  °C, 600  °C or 850  °C with air circulation
• Wire heating elements in the furnaces ceiling for furnaces up to 1200  °C
• SiC heating rods in the furnace ceiling for furnaces up to 1300  °C
• Gas heating as an alternative to electrical heating
• Models for 650  °C and 850  °C with powerful air circulation for better heat transfer onto the charge and to optimize the temperature uniformity
• Very compact design compared with continuous furnaces
• Designed for continuous operation at one working temperature
• Table diameter up to 3000 mm
• Hearth movement in defined segments
• Low-vibration movement of the rotary hearth
• Parallel swivel door
• Motor-driven or rotational motion initiated by foot switch
• Furnace floor can be lowered using a forklift truck for maintenance purposes

Additional equipment

• Customized dimensions
• Exhaust hood above the door opening for discharge of the warm exhaust air when door is open
• Pneumatic drive of the parallel swivel door
• Charging aids for ease of loading and unloading
• Multi-zone control for adjustable thermal profile during the cycle
• Protective gas connections
• Process control and documentation with Controltherm MV software package

Continuous furnaces are the right choice for processes with fixed cycle times such as drying or pre-heating, curing or degassing, etc.. The furnaces are available for various temperatures up to a maximum of 1000 °C. The furnace design depends on the required throughput, the process requirements for heat treatment and the required cycle time. The conveyor technology (e.g. belt, rollers) is tailored to the required working temperature and the geometry of the charge. The conveyor speed and the number of control zones are defined by the process specifications.

Alternative furnace design subject to process specifications:

Conveyor concepts

• Conveyor belt
• Metal conveyor belt with adjusted mesh gauges
• Drive chain
• Roller conveyors
• Pusher-type furnace

Heating systems

• Electric heating, radiant or convection
• Direct or indirect gas-firing
• Infrared heating
• Heating with the use of external heat sources

Temperature cycles

• Control of working temperature across the whole length of the furnace, such as for drying or pre-heating
• Automatic control of a process curve applying defined heat-up, dwell and cooling time
• Control of a temperature curve including a final quenching of the charge

Process atmosphere

• In air
• Under protective gases such as nitrogen, argon or forming gas (95/5)
• Under reaction gases such as hydrogen incl. the necessary safety technology

Basic configuration criteria

• Conveyor speed
• Temperature uniformity
• Operating temperature
• Process curve
• Charge space width
• Charge weights
• Cycle time or throughput
• Length of charge and discharge zone
• Generated exhaust gases
• Specific industry standards such as AMS, CQI-9, FDA etc.
• Other individual customer requirements