Because of comparative economy, the explosion-discharge piece is a kind of dust explosion discharge device commonly used in dust precipitator.Although the explosion-relief chip used for dust precipitator is quite popular at present, there are still the following problems in practical use and design:
1. Calculation of blasting area
If the deflator is used for the discharge of dust precipitator, the commonly used mark for calculating the discharge area is GB/ t15605-2008, en14491-2012 and NFAP 68-2013.At present, the problems existing in the calculation of explosion area in China mainly include:
1) the blasting area is not calculated according to relevant standards, but the size of the bursting disc is selected according to the empirical value or the size of the dust collector.The result may be that the blasting area is not large enough, which affects the blasting effect and causes the explosion pressure in the dust collector to increase, which will lead to the deformation or damage of the dust collector.
2) do not know the explosion characteristics of dust, such as Kst, Pmax, etc.;Dust explosion characteristics Kst and Pmax are the most important and necessary parameters for the calculation of dust explosion area.Common practice is reference standards listed Kst and Pmax value, but the reference and the actual dust in particle size, particle shape is different, humidity, etc, is the most reliable dust explosion characteristics test, in order to get the actual dust Kst and Pmax value;
3) unreasonable selection of parameters for calculation of explosion area, such as values of Pstat and Pred;These two values will affect the calculation results of the blasting area. For example, when the Pred value is small, the calculated blasting area is large.When the Pred value is large, the calculated explosion area is small.How to value Pred is related to the strength of dust collector.
The dense distribution of filter bags or cartridges within the dust collector slows down the propagation of the explosion significantly.In any case, because of the cooling effect of the filter bag or filter tube and there will be no turbulence between the filter bag or filter tube, the propagation speed of the explosion will be reduced.
Is allowed in the latest EN14491 and NFPA 68 standard when calculating the dust catcher explosion venting area, through the comprehensive consideration of filter bag or the volume of the filter cartridge, cartridge filter bag or spacing between the factors such as size, the layout of explosion venting panel location, to the corresponding selection for explosion venting area calculation of the volume of a dust collector.
GB/T 15605-2008 standard 5.2.2 requirements: the volume of the container does not include the volume of the obstacle.If there is any obstacle in the container (such as filter bag, sealing sleeve, filter tube), the volume of the container shall be less than the volume occupied by the filter element or the volume surrounded by the filter medium.
It is recommended to contact a professional manufacturer or relevant personnel to calculate the area of the explosive release when selecting the explosive release chip.