Certain processes release solvents or evolve other flammable vapors when heat is applied. The concentration of these vapors must be kept below a certain limit to prevent ignition. European Norm EN 1539 (formerly VGB4) and NFPA 86 in the USA proscribe the required safety equipment for these processes. For appropriate applications and processes, all air circirculation furnaces of the series N ..HACLS (pages 10, 11 and 13) are available with safety technology for protection of ignition in the furnace chamber. To prevent ignition, flammable vapors must be diluted with air. Special care must be taken so high concentrations of flammable materials do not accumulate in “dead” areas within the furnace. For this purpose, the furnaces are equipped with an exhaust gas fan, providing a defined suction flow. A measurement system monitors this flow. In parallel, the furnace atmosphere is diluted by the inflow of fresh air. The air circulation is also monitored by the measurement system. Furnaces with a capacity greater than 1000 liters are additionally equipped with an explosion pressure relief.

• Defined and monitored exhaust air flow
• Powerful exhaust fan capable of maintaining negative furnace pressure
• Defined and monitored air circulation flow
• Emergency Stop Button
• Visual and audible emergency signals
• Over-temperature limit controller with adjustable cutout temperature for thermal protection class in accordance with EN 60519-2 as temperature limiter to protect the oven and load