Explosion protection

Avoid fires in extraction systems

The particle fineness and the resulting surface area, which can lead to reactivity at a certain size, are of great influence here.

Applications such as blasting, surface coating, burning, welding and grinding in particular are producing ever finer dusts in increasingly large quantities due to ever more efficient processes. If this is not possible or not safe enough, the following measures are available:

• Mechanical pre-separator systems that effectively remove ignition sources such as sparks or hot particles from the extracted air flow before the extraction system.
• Spark extinguishing systems that detect the high-energy particles in the pipe and extinguish them there.

For fine dusts or special processes, passive solutions such as dry extinguishing connections are a simple option. Alternatively, active systems with sensors such as infrared, temperature and smoke detectors are used to intervene automatically. Depending on the process, water, CO2 or powder are used to fight fires in extraction systems.

The hazard triangle as a basis for explosion protection assessment

If the three conditions are met simultaneously (ignition source, fuel and oxygen), the probability of an explosion is given. In turn, this consideration is used for possible solutions, such as the concept of ignition source avoidance.

If it can be safely assumed that no ignition sources will be introduced into the dry separator from outside, we will manufacture it without ignition sources in accordance with ATEX Zone 21 / 22 and the extraction system can be used accordingly.

For this purpose, L+M AG uses only certified components and confirms this with the corresponding device labeling and the declaration of conformity.

Constructive explosion protection for extraction systems

If it is not possible to guarantee that the ignition source can be avoided, e.g. in high-speed processes such as sawing, in mills or for dusts with very low minimum ignition energies, the extraction system must be designed with constructive explosion protection.

• Pressure shock-resistant design with pressure relief via rupture disk to the outside or flame quench into the working chamber, suction-side decoupling and pressure shock-resistant dust discharge.
• Pressure shock-resistant design with explosion suppression, suction-side decoupling and pressure shock-resistant dust discharge.

L+M AG also uses only certified components for this purpose, which is confirmed and guaranteed by the corresponding device labeling and the declaration of conformity. A special feature is the installation of the system in a room classified according to ATEX: In this case, all electrical connections and consumers must be designed for this zone. L+M AG also offers solutions for such applications.