WS Thermal Process Technology

The original with over 30 years of experience: Fire without flame.

The enormous potential of FLOX® was immediately apparent as soon as the effect was discovered. The disappearance of a visible flame and the typical noise associated with it, as well as the drastic reduction in NOx emissions during complete combustion.

Fire without flame - sounds paradoxical and is at the same time a groundbreaking discovery. This combustion principle, which finds a wide range of applications in numerous variants, especially in the steel industry and in burners for heat treatment, has unbeatable advantages. Unlike conventional burners, the sophisticated mixing of fuel gas, combustion air and recirculating exhaust gas in WS burners in FLOX® operation avoids peaks in combustion temperature. Thus, despite the application of high air preheating rates to significantly increase efficiency, the simultaneous increase in NOx emissions can be avoided. In addition, the homogeneous temperature distribution in the kiln ensures high-quality products as well as significantly reduced burner wear. All important factors for environmentally oriented thinking, economic action and the manufacture of high-quality products.

However, the potential of FLOX® technology is far from exhausted. In various national and international projects - partly supported by corresponding subsidies - the focus is on future fields of heat process and energy technology. For years, we have been focusing in particular on adapting our burners to the special requirements of green fuels such as hydrogen, ammonia or methanol. 

  • Optimal for high process temperatures (above 850 °C / above 1,550 F).
  • Drastic reduction of thermal NOx emissions.
  • Improved life of burner components due to reduced thermal wear.
  • Enables highest air preheat ratios.
  • No flame supervision in FLOX® mode necessary.

"FLOX®" = "FLameless OXidation": The registered trademark and patented technology of WS Wärmeprozesstechnik GmbH. Potential NOx problems are finally defused and an energy-efficient and functionally reliable system operation for a sustainable
Productivity established.



WS Rekumat® FLOX® burners offer superior energy efficiency and low-emission heating for industrial furnaces.

Rekumat® CR


The patented REKUMAT® CR burners allow for the first time the substoichiometric operation of a recuperative burner due to the integrated afterburner. Highest efficiency and lowest NOx emissions thanks to FLOX® technology.

Rekumat® C


Energy efficient, ceramic self-recuperative burner for radiant tubes and direct firing

Rekumat® S


Thanks to patented gap-flow technology, REKUMAT® S NT burners achieve the highest energy efficiency with the lowest emissions even at low furnace chamber temperatures below 600 °C.

Flame | FLOX® Video
Flame | FLOX®
Flame Mode FLOX Fashion

Temperature scale from 600 °C to 2.100 °C


Flame Mode

Temperature Flame Mode | Zoom: 10 x 10 mm

OH-Intensity flame mode | Zoom: 10 x 10 mm

FLOX® Mode

Temperature FLOX® Mode | Zoom: 10 x 10 mm

OH-Intensity FLOX® Mode | Zoom: 10 x 10