1. Filtration process
During the filtration process there is no risk of explosion within the filter system because:
- there is no high dust concentration that can cause an explosion
- the body of the filter system as well as the HEPA filter cassettes are grounded and ground-monitored throughout
- each component installed to the filter unit is ATEX conform and certified accordingly.
- the construction of the system does not cause sparks which could cause an explosion.
2. Cleaning process of the HEPA cassette stage 1
During the cleaning process of a HEPA cassette stage 1, a high concentration of dust occurs for a short time, which could cause an explosion.
However, there is no electrostatic charge of the dusts and the air flow in the respective module is stopped, so that no turbulences can occur, which cause an additional risk for an explosion.
Furthermore, the HEPA filter system is designed to be modular construction and the dust laden air side within is limited to 0.2 or 0.3 m³.
An unlikely explosion is due that limited within a filter unit to one module only, which is constructed in a way that it cannot be damaged.
This is why the self-cleaning HEPA filter system does not underlie the ATEX regulation.
Dust laden air duct and production area:
The 10-bar pressure shock resistant dust lade air flaps in each module clearly prevent a pressure or flame from entering the production area via the dust laden air channel.
Clean air duct:
There is no danger to the clean air side because the HEPA filter of stage 1 serves as a flame trap, whereby the HEPA filter of stage 2 remains undamaged and the resulting pressure can gently escape via the clean air duct.
Explosion suppression systems or rupture discs
Due to the design of the self-cleaning HEPA filter system, neither explosion suppression systems, nor rupture discs are necessary.
In case of the filtration of hybrid mixtures, whereby the gas is also explosive,the system does not underlie the ATEX Guideline 2014/34/EU and can be certified by the manufacturer himself.
The explosion protection class
of the Containment Technology filter system corresponds to
To ensure that the HEPA filter module remains undamaged even in the extreme case of an explosion, the design of the HEPA filter system was adapted after explosion tests and appropriate corrective measures were carried out on the housing.