Industrial furnaces
Industrial furnaces

ONEJOON Retort Kiln

For demanding atmospheres (SiH4, H2, Mg, vacuum) and highest requirements on temperature homogeneity in batch process

Discontinuous furnace technology for gas phase deposition (CVD)

of non-metallic powders and the reduction of metallic powders

The ONEJOON retort kiln is the ideal solution for processes with demanding atmospheres such as silanes (SiH4), hydrogen (H2), gaseous magnesium (Mg), vacuum and many more.

A typical application of the retort furnace is the chemical vapor deposition into non-metallic powders as well as the oxygen reduction of metallic powders to obtain a high purity metal grade.

The retort kiln with its unique process gas circulation, consisting of high process gas velocity and optimal process gas guidance directly over the product, allows a homogeneous flow through the entire product structure, which in turn ensures excellent atmosphere and temperature homogeneity. Due to the high process gas circulation, very short heating and cooling rates are possible without compromising atmosphere and temperature homogeneity.

In order to save additional process gas and minimize the cycle time, the process gas exchange is realized by vacuuming the process chamber and then injecting the process gas.

Since the retort furnace is a discontinuous furnace, the space requirement is small and the layout compact.





Processes of Retort Kiln

With ONEJOON retort kilns different processes can be mapped.

These include, for example: 

  • vapor deposition (Chemical Vapor Deposition)
  • reduction of oxygen
  • debinding and presintering
  • special processes
Referenz Retortenofen 02 640x360
Plant engineering

The Retort Furnace in detail

  • Keep your atmosphere inside

    • vacuum-tight design of the retort (outer muffle), especially suitable for demanding atmospheres (SiH4, H2, Mg, vacuum etc.)
    • internal muffle for controlled atmosphere guidance from the retort inner wall to the product

    Safety is our top priority: all our systems are designed according to the Machinery Directive.

  • Atmosphere under control 

    • process gas injection directly into the vacuum tight retort 
    • indirect heating of the process gas on the inner wall of the retort before product contact
    • homogeneous mixing of the process gas by the hot gas fan before product contact
  • Maximum homogeneity directly on the product

    • maximum atmospheric homogeneity with process gas flow directly to the product
    • maximum temperature homogeneity even at low temperatures due to high circulation speeds
    • perfect homogeneity over the entire product pile
    • gastight hot gas fan up to 1000 °C (water cooled)
  • Full power with electric heating elements

    • maximum temperature homogeneity due to indirect heating via retort (external muffle)
    • high life expectancy because no contact with the process gas
    • power reserve also for steep heating ramps
    • CVD simulation for product temperature during the heating process
  • Holistic extraction and exhaust air system

    • suction directly from the vacuum-tight retort (outer muffle)
    • pipeline design
    • integration of combustion chamber / TNV / RNV or further exhaust aftertreatment steps
  • Full cooling power to reduce cycle time

    • steep cooling ramps with powerful cooling fan
    • homogeneous cooling despite steep cooling ramps due to the high process gas circulation in the process chamber
    • CVD simulation for product temperature during the cooling process 
  • Do not lose time during loading and unloading

    • fast loading and unloading of the furnace with easy change of the entire charging rack (complete product stack) 
    • easy loading and unloading of the trays in the charging rack parallel to the running process in order not to lose any process time
System description

How the Retort Kiln works

The correct heat treatment of high-performance ceramics

The fill structure loaded with the products to be manufactured is transported to the furnace floor and lifted upwards via a lifting portal. As soon as the floor has reached its position under the furnace, both are locked together. To prevent heat from escaping and, at the same time, ensure a gas-tight seal, a floating seal with spring-loaded elements is used. The lifting portal is then used for loading and unloading other parallel furnaces.

During the debinding phase (up to 500 °C), the furnace load is heated by circulating hot air, which has previously been preheated by an external heater. The waste gas contaminated with the binder is cleaned in a thermal afterburning plant. At the end of the debinding phase, further heating is carried out by electrical heating elements in the furnace.

The process gas can also be kept in circulation at elevated temperatures up to 800 °C. This contributes to optimum temperature homogeneity during the heating process. The circulation of the process gas ends at temperatures above 800 °C.

Also in the subsequent process steps, no gas or air circulation takes place until the maximum temperature is reached. This is because turbulence in the furnace atmosphere is often very critical for sintering and crystallisation processes. At the end of the process, the workpieces are cooled with tempered air or gas. For this purpose, an external heating system regulates the temperature of the cooling medium in advance before it reaches the product carriers and the products. After cooling down to approx. 250 °C, the furnace floor is transferred from the lifting portal to a cooling chamber where the products are finally cooled down to room temperature.

Schematics with re-circulation gas flow, injection for fresh process gas, outlet for exhaust gas as well as inlet & outlet for cooling air to cool down outer muffle

Retort Kilns from ONEJOON

Advantages at a glance:

  • challenging atmospheres (SiH4, H2, Mg etc.)
  • excellent atmosphere and temperature homogeneity
  • very short heating and cooling rates
  • quick and easy loading and unloading
  • optimised cycle times
  • low space requirement, compact layout

Technical highlights:

  • vacuum-tight retort with inner muffle
  • direct process gas injection
  • optimised process gas circulation with hot gas fan up to 1000 °C
  • powerful indirect cooling
  • charging rack for fast loading and unloading
  • CFD simulation to optimize the process gas flow

Our services

Consulting, service, furnace construction and much more.
Just because every customer has special requirements.

Together with you, we will work out the optimal solution for your request.

  • definition of the scope of delivery
  • design of the system based on your specifications
  • configuration of the system from standardised components, customer-specific adaptations
  • presentation of the plant concept
  • preparation of the offer
  • design, production and testing of the system in our factory
  • shipping, assembly, commissioning and acceptance of the plant at your location around the globe
  • preparation of the plant documentation and the CE declaration of conformity
  • production support
  • services: plant maintenance, spare parts, repairs, measurements
  • network to adjacent processes

We are looking forward to your request, contact us today!


Selected references

Satisfied customers - the best proof of successful cooperation.

Vapor phase deposition (CVD) for battery powder

Dates & Facts

  • customer: American manufacturer 
  • product: Anode powder
  • plant: retort furnace 
  • year of construction: 2020
  • scope of supply: plant design, engineering, construction, installation at the customer's site, commissioning, process support and process consulting
Referenz Retortenofen 02 640x360
Oxygen reduction of metallic powders

Dates & Facts

  • customer: European manufacturer 
  • product: high purity metal powder
  • plant: retort furnace 
  • scope of supply: plant design, engineering, construction, construction, installation at customer site, commissioning, process support and process consulting
ONEJOON Service Technischer Support Grafik 840x560


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About us

More than 125 years of expertise in industrial furnace construction

Get to know ONEJOON
24/7 Emergency Service Hotline +49 551 820 830 - 840
Matthias Muck Senior Expert +49 551 820 830 - 300
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