The high-temperature furnaces HT 04/16 - HT 450/18 have proven reliability over many years in laboratory and production. Whether for quartz glass or glass ceramics, for sintering CIM components or for other processes up to a maximum temperature of 1800 °C, these furnaces afford the optimal solution for the sintering process.

High-temperature furnaces can either be insulated with fiber material or lightweight refractory bricks. Furnaces with fiber insulation achieve significantly shorter heating up times because of the low thermal mass. An insulation made of lightweight refractory bricks (see HFL models on page 32), on the other hand, has the advantage of better chemical stability.

These furnaces can also be tailored to specific processes by means of a wide range of additional equipment. The addition of a debinding package, for example, allows the use of these models as combi furnace for debinding and sintering in one process. Thermal or catalytic exhaust cleaning equipment rounds-off the system.

• Tmax 1600  °C, 1750  °C or 1800  °C
• Recommended working temperature 1750 °C (for models HT ../18), increased wear and tear must be expected in case of working at higher temperatures
• Dual shell housing with fan cooling for low shell temperatures
• Heating from both sides via molybdenum disilicide heating elements
• High-quality fiber insulation backed by special insulation
• Side insulation constructed with tongue and groove blocks provides for low heat loss to the outside
• Long-life roof insulation with special suspension
• Chain-guided parallel swivel door for defined opening and closing of the door
• Two-door design (front/back) for high-temperature furnaces > HT 276/..
• Labyrinth sealing ensures the least possible temperature loss in the door area
• Reinforced floor as protection for fiber insulation as standard from models HT 16/16 upwards
• Exhaust air opening in the furnace roof
• Heating elements switched via thyristors
• Over-temperature limiter with adjustable cutout temperature for thermal protection class 2 in accordance with EN 60519-2 as temperature limiter to protect the furnace and load
• Defined application within the constraints of the operating instructions
• NTLog Basic for Nabertherm controller: recording of process data with USB-flash drive

Additional equipment

• Uncontrolled or controlled cooling system with frequency-controlled cooling fan and motor-driven exhaust air flap
• Furnace in DB design featuring fresh air preheating, exhaust gas ventilation and an extensive safety package for debinding and sintering in one process, i. e. without transfering the material from the debinding furnace to the sintering furnace
• Stainless steel exhaust gas hoods
• Commissioning of the furnace with test firing and temperature uniformity measurement (also with load) for the purpose of process optimization
• Temperature measurement with thermocouples, types B and type S with automatic pull-out device for precise control results in the low temperature range
• Protection grid in front of the heating elements to prevent mechanical damages
• Special heating elements for zirconia sintering provide for longer service life with respect to chemical interaction between charge and heating elements
• Protective gas connection for purging the furnace with non-flammable protective or reaction gases
• Manual or automatic gas supply system
• Inner process box to improve the gas tightness and to protect the furnace chamber against contamination
• Lift door
• Bottom insulation made of durable lightweight refractory bricks for heavy charge weights
• Motorized exhaust air flap, switchable via the program
• Exhaust air and exhaust gas piping
• Thermal or catalytic exhaust cleaning systems
• FID measurement for process optimization
• Process control and documentation via VCD software package or Nabertherm Control Center (NCC) for monitoring, documentation and control

The high-temperature furnaces HTC 16/16 - HTC 450/16 are heated by vertically hung SiC rods, which makes them especially suitable for sintering processes up to a maximum operating temperature of 1550 °C. For some processes, e.g. for sintering zirconia, the absence of interactivity between the charge and the SiC rods, these models are more suitable than the alternatives heated with molybdenum disilicide elements. The basic construction of these furnaces make them comparable with the already familiar models in the HT product line and they can be upgraded with the same additional equipment.

• Tmax 1550  °C
• Dual shell housing with fan cooling for low shell temperatures
• Heating from both sides via vertically mounted SiC rods
• High-quality fiber insulation backed by special insulation
• Side insulation constructed with tongue and groove blocks provides for low heat loss to the outside
• Long-life roof insulation with special suspension
• Chain-guided parallel swivel door for defined opening and closing of the door without destroying the insulation
• Two-door design (front/back) for high-temperature furnaces > HTC 276/..
• Labyrinth sealing ensures the least possible temperature loss in the door area
• Reinforced floor as protection for fiber insulation and to load heavy weights
• Exhaust air opening in the furnace roof
• Heating elements switched via SCR‘s
• Over-temperature limiter with adjustable cutout temperature for thermal protection class 2 in accordance with EN 60519-2 as temperature limiter to protect the furnace and load
• Defined application within the constraints of the operating instructions
• NTLog Basic for Nabertherm controller: recording of process data with USB-flash drive

Additional equipment like HT models

The high-temperature furnaces HFL 16/16 - HFL 160/17 are characterized by its lining with robust refractory insulation. Compared with the fiber-insulated models of the HT product line, these furnaces are recommended when high charge weights have to be sintered. In most cases lightweight refractory brick insulation is also significantly more resistant to gas emissions occurring during heat treatment.

Standard equipment like high-temperature furnaces HT, except:

• Tmax 1600  °C or 1700  °C
• Robust refractory brick insulation and special backing insulation
• Furnace floor made of lightweight refractory bricks accommodates high charge weights
• Defined application within the constraints of the operating instructions
• NTLog Basic for Nabertherm controller: recording of process data with USB-flash drive

Additional equipment like HT models

The gas-fired high-temperature furnaces of the HTB product line are specially developed for applications requiring fast heating up ramps. Gas-fired high-temperature furnaces are preferred also if inflammable gases are produced in large amounts during the process. A large content of the gas emissions are already burned in the furnace chamber, so that downstream equipment like thermal and catalytic exhaust cleaners can accordingly be downsized. The furnaces are insulated with highly heat-resistant and long-life lightweight refractory brick insulation or fiber materials.

• Tmax 1600  °C
• Powerful, sturdy high-speed burners with pulse control and special flame guidance in the furnace chamber provide for good temperature uniformity
• Operation with natural gas, propane or liquified gas
• Fully automatic PLC control of the temperature, including monitoring of the burner function
• Gas fittings according to DVGW (German Technical and Scientific Association for Gas and Water) with flame monitoring and safety valve
• Reduction-resistant fiber insulation with low heat storage provides for short heating and cooling times
• Dual shell housing provides for low outside temperatures
• Exhaust hood with fittings for further discharge of the exhaust gases
• Defined application within the constraints of the operating instructions
• NTLog Basic for Nabertherm controller: recording of process data with USB-flash drive
• PLC control with touch panel as user interface

Additional equipment

• Automatic lambda control to set the furnace atmosphere
• Exhaust air and exhaust gas piping
• Recuperator burners
• Thermal or catalytic exhaust cleaning systems
• Process control and documentation via Nabertherm Control Center (NCC) for monitoring, documentation and control

For charging complex settings we recommend top hat furnaces or bottom loading furnaces. Also small workparts can be conveniently loaded on different layers.

The basic furnace comes with one table. Depending on the technical requirements are equipped, a top hat furnace or a bottom loading furnace will be the choice. The system can be expanded with one or more changeable tables, either manually or electrically driven. Other additional equipment, like controlled cooling systems to short process cycles or the addition of a debinding package for debinding and sintering in one process provide for tailored solution for individual needs.

• Tmax 1600  °C, 1750  °C or 1800  °C
• Dual shell housing with fan cooling provides for low shell temperatures
• Top hat furnaces: electrohydraulically driven top hat with fixed table
• Bottom loading furnaces: driven table and fixed top hat
• Gently running, low-vibration spindle drive or electrohydraulic drive for larger models
• Safe and tight closing of the furnace by means of labyrinth seal
• Heating from all four sides provides for good temperature uniformity
• High-quality fiber insulation backed by special insulation
• Side insulation constructed with tongue and groove blocks provides for low heat dissipation to the outside
• Long-life roof insulation with special suspension
• Furnace table with special bottom reinforcement to accommodate high charge weights
• Motor-driven exhaust air flap in the furnace roof, switchable at the program
• Heating elements switched via SCR‘s
• Over-temperature limiter with adjustable cutout temperature for thermal protection class 2 in accordance with EN 60519-2 as temperature limiter to protect the furnace and load
• Defined application within the constraints of the operating instructions
• NTLog Basic for Nabertherm controller: recording of process data with USB-flash drive

Additional equipment

• Uncontrolled or controlled cooling system with frequency-controlled cooling fan and motor-driven exhaust air flap
• Furnace in DB design featuring fresh air preheating, exhaust gas ventilation and an extensive safety package for debinding and sintering in one process, i. e. without transfering the material from the debinding furnace to the sintering furnace
• Stainless steel exhaust gas hoods
• Commissioning of the furnace with test firing and temperature uniformity measurement (also with load) for the purpose of process optimization
• Temperature measurement with thermocouples, types B and type S with automatic pull-out device for precise control results in the low temperature range
• Special heating elements for zirconia sintering provide for longer service life with respect to chemical interaction between charge and heating elements
• Heat from all sides and between the stack or with heating elements, positioned above each other to optimize temperature uniformity
• Protective gas connection for purging the furnace with non-flammable protective or reaction gases
• Manual or automatic gas supply systems
• Inner process box to improve the gas tightness and to protect the furnace chamber against contamination
• Bottom insulation made of durable lightweight refractory bricks for heavy charge weights
• Gas supply system in the furnace chamber with ceramic bell jar, protective gas inlet and outlet from below for better sealing when operating with protective gases and/or to prevent from chemical interactions between the load and the insulation or the heating elements
• Alternative table changing systems
• Exhaust air and exhaust gas piping
• Thermal or catalytic exhaust cleaning systems
• FID measurement for process optimization
• Process control and documentation via VCD software package or Nabertherm Control Center (NCC) for monitoring, documentation and control