Re: Atex Certification
To protect equipment by venting requires establishing either :-
1) the required vent area according to enclosure volume, Kst for the dust, Pstat (the static pressure at which the vent operates), Pred (the allowable static pressure for the enclosure).
or
2) the required Pred (the allowable static pressure for the enclosure) according to enclosure volume, Kst for the dust, Pstat (the static pressure at which the vent operates), and the vent area that can be accomodated.
Most often (1) above is used, but sometimes where space to fit vents is limited it's necessary to to use (2), working back from the vent area to get the vessel strength.
In either case the values of Pstat and Pred have been under STATIC conditions. There is a draft European Standard prEN 14491 on "Dust Explosion Venting" but I don't know if this will change how Pstat and Pred are used. ■
Atex Certification
Good morning at all of you,
my name is Matteo Artioli, and I'm working for a company which manufact screw conveyor, filter, bin activator etc...
We trying to do the autocertification about class 3, zone 22 according to ATEX 94/9/EC for our machines.
In order to know how the P.red is, we are thinking to perform finite elements calculation, but our doubt is if in these calculations we have to consider static or dinamic load. Infact reading on the norms VDI 3673 and NFPA 68/69 it seem that for all strength calculation (for example in the sizing of vent pannel) static load has to be considered, but during an explosion the pressure changes in the time with a specific curve.
If someone knows how to perform this FEM calculations (static or dinamic) and also who are able to do this (university/company etc), please contact me.
Best Regard
Matteo Artioli. ■