In order to form an explosive atmosphere, the substances in question must be flammable and can be in the form of powder, gas or liquid. Typically, these flammable or explosive substances are explosive as a dust-air mixture if their particle diameter is less than 500 µm. However, some dusts can even be explosive up to a grain diameter of 1 mm.

Flammable solids:

• Plastics
• Organic substances (flour, coffee, starch, cellulose …)
• Metals (aluminum, magnesium …)

Flammable gases:

• Natural gas
• Hydrogen
• Acetylene

Flammable liquids:

• Disinfectant
• Organic solvents
• Treibstoffe

There are two techniques to prevent explosions caused by explosive substances:

Primary explosion protection
The primary explosion protection principle means the preventive avoidance of an explosive dust air mixture and the use of special protective measures. This approach is considered the most reliable technique for preventing explosions. Possible techniques are:

• Dilution of the explosive substances
• Passivation of the explosive substances
• Spark avoidance

All extraction systems from ABSAUGWERK are built according to the primary explosion protection principle and can also be operated indoors.

Secondary explosion protection
With secondary explosion protection, ignition is prevented by any ignition sources in the hazardous area, but the explosive atmosphere (dust-air mixture in an explosive concentration) remains.

The type plate can be used to check whether or not an extraction system or other equipment may be used in areas where there is a risk of dust explosion.

Mandatory information on the rating plate:

• CE mark
• Ex-sign (hexagonal explosion protection sign)
• Serial number
• Machine type
• Year of manufacture
• Device group (II)
• Device category (3D here)
• Surface temperature (Motor nameplate)
• IP protection class (Motor nameplate)

Specific information on other ATEX components, for example the motor, is shown on the rating plate of the respective component.

It is necessary to provide information on all electrical components in the Ex zone area. In our extraction systems, the control cabinet with the control unit is installed outside the system, which ensures that it is not located in the Ex zone.