Θερμική τεχνολογία

Rotary Hearth Furnaces up to 1300 °C with and without Air Circulation Electrically Heated or Gas-Fired

Rotary hearth furnace DH 3020/1480/450/11, movable on rails, for preheating of molds for two forges Rotary hearth furnace DH 2100/0/750/13S

Gear rim drive under the rotary hearth furnace

Rotary table with base plates made of highly heat-resistant steel to protect the insulation

Exhaust hood above charging opening

Pre-heating of steel rings for forging in a rotary hearth furnace

Furnace bottom can be lowered for maintenance purposes

The rotary hearth 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 rotary hearth 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
  • Rotary hearth furnaces 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 bottom can be lowered using a forklift truck for maintenance purposes
  • Defined application within the constraints of the operating instructions

Additional equipment

  • 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 via VCD software package for monitoring, documentation and control
Size examplesTmaxInner dimensions in mmVolumeOuter dimensions in mmHeatingElectricalWeight
Model°CØ OuterØ Innerhin lWDHpower in kW1connection*in kg
DH 1200/-/300/1111001200030034022002200250054.03-phase1000
DH 1500/800/250/111100150080025063024002300245021.03-phase1500
DH 3020/1480/450/11110030221480450250040004000250098.03-phase3500
DH 2100/0/750/13S1300210007502600336433642701650.0gas-fired8300
1Depending on furnace design connected load might be higher *Please see page 81 for more information about supply voltage
 

Continuous Furnaces Electrically Heated or Gas-Fired

Continuous furnace D 1500/3000/300/14 for thermal ageing with mesh belt transport system and subsequent cooling station Roller continuous furnace N 650/45 AS for heat treatment of heavy workparts

Continuous furnace for bulk materials in baskets

Conveyor plant D 1600/3100/1200/55, consisting of solution annealing furnace, cooling station and conveyor system

Mesh belt drive in a continuous furnace

Continuous furnace D 700/10000/300/45S with chain conveyor for 950 °C, gas-fired

Continuous furnace D 1100/3600/100/50 AS for annealing of springs incl. charging and discharging system

Mesh belt drive in continuous furnace D 1100/3600/100/50 AS

Rotary hearth furnace for preheating

Continuous furnaces are the right choice for processes with fixed cycle times such as drying or preheating, curing, aging, vulcanisation or degassing. The furnaces are available for various temperatures up to a maximum of 1400 °C. The furnace design depends on the required throughput, the process requirements for heat treatment and the required cycle time. The conveyor technology is tailored to the required working temperature, geometry and weight of the charge and to the requirements regarding available space and integration into the process chain. The conveyor speed and the number of control zones are defined by the process specifications.

Conveyor concepts

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

Heating systems

  • Electric heating, radiation or convection
  • Direct or indirect gas-fired
  • 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 preheating
  • Automatic control of a process curve applying defined heat-up, dwell and cooling time
  • Heat treatment including a final quenching of the charge

Process atmosphere

  • In air
  • For processes with organic outgassings incl. mandatory safety technology according to EN 1539 (NFPA 86)
  • In non-flammable protective or reactive gases such as nitrogen, argon or forming gas
  • In flammable protective or reactive gases such as hydrogen incl. the necessary safety technology

Basic configuration criteria

  • Conveyor speed
  • Temperature uniformity
  • Operating temperature
  • Process curve
  • Work 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
 

Wire and Strand Annealing Furnaces

Strand annealing furnace D 390/S

D 250/S in production

Strand annealing furnaces based on a tube furnace with a length of 6 meters

These models are particularly suitable for continuous heat treatment at operation temperatures up to 1200 °C. The modular design allows adjustment to different length and width requirements. The heating elements are mounted on only one side of the furnace and can be changed individually during operation. Optimum temperature uniformity is achieved by means of a multiple zone control system tailored to the furnace dimensions.

  • Tmax 1200  °C
  • Modular design, variable length
  • Small outer dimensions due to efficient microporous silica insulation
  • Special heating elements that can be changed during operation
  • Heating from the ceiling
  • Optimum temperature uniformity by means of multiple zone control
  • Defined application within the constraints of the operating instructions

Additional equipment

  • Gas supply systems for non-flammable or falmmable protective or reaction gases including hydrogen in the muffle tubes, with burn off torch and safety technology
  • Process and charge documentation
  • Double chamber furnace system with parallel chambers for simultaneous operation at different temperatures
  • Process control and documentation via VCD software package or Nabertherm Control Center (NCC) for monitoring, documentation and control
ModelTmaxInner dimensions in mmVolumeOuter dimensions in mmHeatingElectrical
 °Cwdhin lWDHpower in kW1connection*
D 20/S1200400100050209001200135093-phase
D 30/S120060010005030110012001350123-phase
D 50/S12002003600505070040001150153-phase
D 60/S12002005600506070060001350363-phase
D 70/S12003503600507085040001100363-phase
D 110/S120048046005011098050001450363-phase
D 130/S 1200650360050130115040001150603-phase
D 180/S120048076005018098080001350803-phase
D 250/S1200950560050250140060001350803-phase
D 320/S120085076001003201400800013501603-phase
1Depending on furnace design connected load might be higher *Please see page 81 for more information about supply voltage