Dust Mask with a Pressure Drop Measuring Device

Abstract

Introduction. Respiratory diseases are the leaders among the scope of occupational diseases. This result from air pollution in working area by hazardous air disperse particles, gases, vapours or using individual respiratory protective devices (IRPD), which do not allow control of respiratory-protection period and thus increase the risk of occupational diseases.
Theoretical analysis of protective efficiency of dust respirators and research purpose statement. The use of dust respirators is associated with the following operational problems: protection factor is significantly reduced during the work activities, so it is needed to replace filtering components very often; non filtrated air leaks through the obturation line of half mask as a result of no uniform distribution of pressure; control of respiratory-protection period of filters is impossible.
Design of dust respirator with differential pressure meter. The solution of the problem is suggested as change of dust respirator by adding of differential pressure meter consisting of pressure control sensor, unit of control and information processing, appliance for information recording and storage, signal unit, and power source. The suggested design of dust respirator enables improvement of protection properties and reduction of air leakage through the gaps between obturation line and worker’s face occurring during the work activities because of head harness weakening or exceeding of resistance of filters performance and determining of critical state of their exploitation.
Algorithm development for pressure meter operation of dust respirator. Pressure sensor is placed under the respirator mask. Its output is connected to input of unit of control and information processing, which transmits data to signal unit and appliance for information recording and storage. After the processing the information is compared to settings and control signals are transmitted to turn on light and sound indicators. Moreover, the information is recorded to be stored in appliance for information recording and storage. Alert sounds of variable duration and cycles depending on pressure under the mask during the air inhalation are easy-to-see in darkness and are likely to attract worker’s attention.
Experimental studies of workability of dust respirator with pressure meter. Laboratory workability check of pressure meter of respirator has demonstrated similarity of measuring results of pressure difference in filters in case of dusting. The periods were determined for pressure meter signals the need in filter change and in case of half mask sliding during the work activities resulting in new gaps.
Discussion. The main feature of the developed dust respirator in comparison with the common ones in sale is permanent monitoring of pressure difference under the mask. It enables determining of actual protection period of filters and provides the right place of mask on face as being controlled by the maintenance of minimum value of air exhaustion under the mask. The level of worker protection during work activities wearing IRPD is determined with respect to the indicators. Thus, addition of pressure meter into IRPD enables improvement of workers’ protection from dust during their work activities.
Conclusions. The design of pressure meter for dust respirator was developed. The algorithm of meter operation was proposed; it enables control of change of breath pressure difference using increase of filters resistance resulting from dust deposits on their surface, improper seal of respirator half mask and worker’s face during the work activities.