Abstract
In this paper, a solution to the problem of the change in the pressure drop in a respirator filter during cyclic air motion is suggested since the current theory of filtering is based on steady-flow processes. The theoretical dependence of the pressure drop in the respirator filter on air flow rate is determined, which is represented by the harmonic law, which characterizes the human respiration process during physical work. For the calculation, a filter model was used, which is represented by a system of parallel isolated cylinders with a length equal to the total length of the filter fibres surrounded by porous shells formed by a viscous air flow field, with a size determined by the equal velocities of the radial component of air flow and undisturbed flows. The flow-around process in the proposed model of air flow through the respirator filter is described by the Brinkman equation, which served to establish the total air flow resistance in the proposed system under conditions of velocity proportionality. It consists of two parts: the first characterizes the frictional resistance of the air flow against the surface of the cylinder, which imitates the filter fibre; the second—the inertial part—characterizes the frequency of pulsations of respiratory movements during physical performance. The divergence of the analytical results and experimental studies is no more than 20%, which allows the use of the established dependence to estimate the change in pressure drop in a respirator filter made of filter material “Elephlen” when the user carries out different physical activities. This allows the period of effective protective action of respirators with different cycles of respiration during physical activities to be specified, which is a very serious problem that is not currently regulated in health and safety regulations, and it also allows the prediction of the protective action of filters and respiratory protection in general.
Highlights
The resistance of filters to air flow is one of the most important indicators of filter respirators [1,2,3]
The purpose of this research is to solve theoretically the problem of determining the value of the pressure drop on a respirator filter, which is represented by a system of parallel isolated cylinders during the oscillating movement of the air flow with the different modes of physical activity of a worker performing production functions
The experimental data obtained on the value of the pressure drop on the filter respirator when simulating the process of breathing, corresponding to works of different difficulty, is shown in Figure 1 in the form of points
Summary
The resistance of filters to air flow is one of the most important indicators of filter respirators [1,2,3]. In studies by A.T. Johnson [8], data on the reduction in the working capacity of workers by 25–30% when using masks with resistance to breath of 80 PA are given. There are publications on the dependence of the resistance to air flow, passing through filters, on the permeability of aerosol particles through them into the space under a mask of a filter respirator [9]. A previous study [10] determines the influence of the filter structure (fibre diameter, package density) on resistance to breath and protective properties
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
