Abstract
Objective is to determine the relation between pressure difference of a filter and parameters of a filtering layer to lengthen the protection period. The study involved elements of system analysis and mathematical modeling. Basic statements of the theory of nonstationary filtration and aerohydrodynamics were applied to develop a dust-loaded filter model. Dependence of pressure difference in a filter upon certain changes in packaging density of dust-loaded fibers has been determined; the dependence makes it possible to define minimum fiber packaging density to provide maximum dust capacity. To provide maximum dust capacity and high protective efficiency, the number of filtering layers in multilayered filters depends upon dust concentration within the air of the working zone, specified protection level of a respirator, air loss, and maximum dust volume which may be accumulated in the finishing filtering layer in terms of fiber packaging density being determined according to the minimum pressure difference in a filter at final time of respirator operation. A model of changes in pressure difference in filtering respirators in the process of aerosol particles depositing on filters has been improved; contrary to other available models, that one takes into consideration changes in fiber packaging density while dusting, filtration coefficient, and the amount of aerosol particles.
Highlights
Coal dust does contaminate atmospheric air and environment [1], it is dangerous for those peoples working immediately at mining enterprises
Determination of the mentioned relation is of special importance to calculate the parameters of multilayered filters when there is the necessity in defining packaging density of previous filtering layers
Process of volumetric filtering of aerosol particles is capable of increasing protective period of filters. It is especially required for multilayered filters. Since it is the time of pore plugging of a previous layer that is the determining one to calculate the parameters of a finishing layer, the analysis of the obtained dependences makes it possible to state that fiber packaging density has the most considerable effect upon the increase in pressure difference at minor filtration rates being up to 0.01 m/s while dusting
Summary
Coal dust does contaminate atmospheric air and environment [1], it is dangerous for those peoples working immediately at mining enterprises. Gasification process takes place within a closed system: underground generator – ground complex that practically restricts the emission of harmful generator gases into the environment [9]. To provide high-efficiency dust protection, it is required to use low breathing resistance respirators which are characterized by minor effect upon functional state of workers. Otherwise, they will not be used during the whole shift [15]. The studies aimed at the improvement of ergonomic parameters of respiratory protective devices are of special topicality [10, 11, 16]
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