Fiber Optics/Glass /
Retort Furnaces

Hot-Wall Retort Furnaces up to 1100 °C

Retort furnace NRA 150/09 with automatic gas injection and process control H3700 Retort furnace NRA 25/06 with gas supply system

Inside heating in retort furnaces NRA ../06

Bayonet quick-lock for the retort, also with electric drive as additional equipment

Parallel guided door to open the hot retort furnace as additional equipment

These gas tight retort furnaces are equipped with direct or indirect heating depending on temperature. They are perfectly suited for various heat treatment processes requiring a defined protective or a reaction gas atmosphere. These compact models can also be laid out for heat treatment under vacuum up to 600 °C. The furnace chamber consists of a gas tight retort with water cooling around the door to protect the special sealing. Equipped with the corresponding safety technology, retort furnaces are also suitable for applications under reaction gases, such as hydrogen or, in combination with the IDB package, for inert debinding or for pyrolysis processes.

Different model versions are available depending on the temperature range required for the process:

Models NRA ../06 with Tmax 650 °C

  • Heating elements located inside the retort
  • Temperature uniformity up to +/- 5 °C inside the worke space
  • Retort made of 1.4571
  • Gas circulation fan in the back of the retort provides for optimal temperature uniformity

Models NRA ../09 with Tmax 950 °C

  • Outside heating with heating elements around the retort
  • Temperature uniformity up to +/- 5 °C inside the worke space
  • Retort made of 1.4841
  • Fan in the back of the retort provides for optimal temperature uniformity

Models NR ../11 with Tmax 1100 °C

  • Outside heating with heating elements around the retort
  • Temperature uniformity up to +/- 5 °C inside the worke space
  • Retort made of 1.4841
 

Retort furnace NRA 25/09 Retort furnace NRA 50/09 H 2

Vacuum pump for cold evacuation of the retort

Process control H3700 for automatic version

Basic version

  • Compact housing in frame design with removable stainless steel sheets
  • Controls and gas supply integrated in the furnace housing
  • Welded charging supports in the retort or air-baffle box in the furnace with atmosphere circulation
  • Swivel door hinged on right side with open cooling water system
  • Depending on furnace volume for 950 °C- and 1100 °C-version the control system is divided in one or more heating zones
  • Temperature control as furnace control with temperature measurement outside the retort
  • Gas supply system for one non-flammable protective or reaction gas with flow meter and manual valve
  • Port for vacuum pump for cold evacuation
  • Operation under vacuum up to 600  °C with optional single-stage rotary vane pump
  • Defined application within the constraints of the operating instructions
  • NTLog Basic for Nabertherm controller: recording of process data with USB-flash drive

Additional equipment

  • Upgrade for other non-flammable gases
  • Automatic gas injection, including MFC flow controller for alternating volume flow, controlled with process control H3700, H1700
  • Vacuum pump for evacuating of the retort up to 600  °C, attainable vacuum up to 10 -5mbar subject to selected pump
  • Cooling system for shortening process times
  • Heat exchanger with closed-loop cooling water circuit for door cooling
  • Measuring device for residual oxygen content
  • Door heating
  • Temperature control as charge control with temperature measurement inside and outside the retort
  • Gas inlet with solenoid valve, controlled by the program
  • Process control and documentation via VCD software package or Nabertherm Control Center (NCC) for monitoring, documentation and control
 

Retort furnace NRA 300/09 H 2for heat treatment under hydrogen Charging of the retort furnace NRA 300/06 furnace with a pallet truck
H 2Version for Operation with Flammable Process Gases

When a flammable process gas like hydrogen is used, the retort furnace is additionally equipped with the required safety technology. Only certified and industry proven safety sensors are used. The furnace is controlled by a fail-safe PLC control system (S7- 300F/safety controller).

  • Supply of flammable process gas at controlled overpressure of 50 mbar relative
  • Certified safety concept
  • PLC controls with graphic touch panel H 3700 for data input
  • Redundant gas inlet valves for hydrogen
  • Monitored pre-pressures of all process gases
  • Bypass for safe flushing of furnace chamber with inert gas
  • Torch for thermal post combustion of exhaust gases
  • Emergency flood container for purging the furnace in case of failore
 

Retort furnace NR 150/11 IDB with thermal post combustion
IDB Version for Debinding under Non-flammable Protective Gases or for Pyrolysis Processes

The retort furnaces of the NR and NRA product line are perfectly suited for debinding under non-flammable protective gases or for pyrolysis processes. The IDB version of the retort furnaces implements a safety concept by controlled purging the furnace chamber with a protective gas. Exhaust gases are burned in an exhaust torch. Both the purging and the torch function are monitored to ensure a safe operation.

  • Process control under monitored and controlled overpressure of 50 mbar relative
  • Process control H 1700 with PLC controls and graphic touch panel for data input
  • Monitored gas pre-pressure of the process gas
  • Bypass for safe flushing of furnace chamber with inert gas
  • Torch for thermal post combustion of exhaust gases
ModelTmaxModelTmaxWork space dimensions in mmWork spaceElectrical
 °C °Cwdhin lconnection*
NRA 17/..650 or 950NR 17/111100225350225173-phase
NRA 25/..650 or 950NR 25/111100225500225253-phase
NRA 50/..650 or 950NR 50/111100325475325503-phase
NRA 75/..650 or 950NR 75/111100325700325753-phase
NRA 150/..650 or 950NR 150/1111004507504501503-phase
NRA 200/..650 or 950NR 200/11110045010004502003-phase
NRA 300/..650 or 950NR 300/1111005909005903003-phase
NRA 400/..650 or 950NR 400/11110059012505904003-phase
NRA 500/..650 or 950NR 500/11110072010007205003-phase
NRA 700/..650 or 950NR 700/11110072013507207003-phase
NRA 1000/..650 or 950NR 1000/111100870135087010003-phase
*Please see page 69 for more information about supply voltage