Explosion pressure venting
In extraction systems, dust explosion incidents are a potential risk that must not be underestimated. Depending on the "zone", devices and plants must demonstrate certain levels of protection. In this regard, thirteen possible sources of ignition need to be examined for their relevance. The appropriate protective measures are then determined based on this examination. Explosion pressure venting prevents overpressures in filter systems, for instance. Pressure venting is used where there are non-toxic dusts.
During an explosion in a container like a filter or silo, rupture discs prevent excessive pressure from building up. If the response pressure is exceeded during an explosion, the rupture discs will rupture in a controlled way. It is important that no parts fly out in the process. Flames will escape from the released opening in a range extending from a few metres to up to 60 metres due to the overpressure in the container, causing pressure effects in the external area.
This cost-effective pressure-venting method is widely used in industry.
- Not reusable
- Pressure venting within buildings is not permitted due to the effects of pressure and flames outside of the container
- Not permitted where there are toxic or carcinogenic dusts and their combustion products
- Sometimes large safety areas are required in the venting area
The letter Q stands for "quenching". Like conventional venting, a rupture disc is also used but unlike other options, it has a downstream stainless steel mesh cage, which extinguishes any flames escaping as a result of the explosion. The pressure effects in external areas are significantly reduced.
- Only small safety areas are required in the external area
- Can be discharged in a building
- Reusable; simply clean the mesh cage and replace the rupture disc.
- More expensive
This option also requires a defined opening surface on the container that will be released in the event of an explosion. In this case, the venting mechanism is a damper blade, which springs open if a defined response pressure is exceeded. After an explosion, the damper blade returns to its original closed position by the force of gravity.
- Prevents oxygen from entering, which would cause a fire in the filter, silo or other areas The escaping flame has a low range due to the low response pressure of the explosion flap
- More expensive