In case of an explosion these weak points open and the explosion pressure is released. In most cases as weak elements so-called bursting discs are applied. In case of an explosion these bursting discs open already at a low pressure, as a result of which the pressure in the thus protected vessel does not rise above an (in advance determined) value (the reduced explosion pressure).
For a good functioning the total effective venting area, the opening pressure and the correct placement of the bursting discs are of great importance. Apart from this also the type of bursting disc has to be right for the application intended. Furthermore one should mind the temperature and vacuum resistance, possible insulation to prevent condensation etc.
A correct positioning of the vent is important. A rupture disc may not be placed in such way that, when it opens in case of an explosion, it could constitute a danger for the surrounding area. So, never directed at an area where regularly people are present. Do keep in mind that the flame jet of an explosion, coming out of a rupture disc, has a huge length and width (can also be calculated according to VDI 3673).
The other way around the rupture disc has to be positioned in such a way that the explosion can freely pass through. To place filter bags or other obstructions in front of a rupture disc is fundamentally wrong: in case of an explosion these will be blown into the vent opening and will obstruct it (at least partially), unless the latter has been fully tested and certified.
In some cases it is impossible to vent to the outside, either because the vessel concerned is too far away from an exterior wall, or in those cases where there is no safe environment behind the exterior wall. For those cases venting equipment is available with integrated flame arresting elements. This way, even in a danger zone, explosion venting can be applied.
ProDetec | Fire & Gas Detection; Spark & Hot Ember Detection
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