Study of protective efficiency of respirator with forced air supply

The aim of the work was to conduct experimental studies aimed at determining the protection factor of the filter respirator with forced air supply by volunteers in different modes of operation and to establish the dependence of the amount of air supplied by the fan from the air purification device to the filter’s resistance. Simulation studies to determine the protective effectiveness of the filter respirator on the testers were performed according to the procedure for determining the penetration coefficient of test aerosol – sodium chloride, as the ratio of the submask concentration of test aerosol to the ambient concentration formed in a special chamber that meets the requirements of DSTU EN 13274. Determination of the amount of air supplied by the air purification unit to the submask space and assessment of the value of positive pressure inside the mask was performed according to the procedure described in DSTU EN 12941: 2004. As a result of simulated laboratory tests to determine the protective effectiveness of filter respirators with forced air supply to the testers, it was found that the average result of the protection factor of the test samples ranged from 99.93 to 99.97, which meets the requirements of DSTU EN 12941: 2004. In addition, it was found that the amount of air treated by the fan of the air purification device for clean filters is 165 and 215 dm3/min for operating modes “Normal” and “Turbo”, while for the polluted filters it is reduced to 131 and 185 dm3/min, respectively. During the study, the compliance of the value of excess pressure in the submask space with the requirements of DSTU EN 12941: 2004, which should not exceed 2.5 mbar, was confirmed. It is also determined that the stability of the technical parameters of the air purification device is maintained in the specified range when charging the “Dinogy Li-Pol 11000mAh 14.8V 4S 25C” brand battery not less than 12 V to ensure the current value of not less than 1.6 A. The practical value of the results lies in determining the duration of protective action of the filter respirator, the choice of filter resistance to establish the scope and modes of operation in the developed personal respiratory protection equipment

Improvement of the procedure of new filter masks development

The purpose is to substantiate theoretically the design of elastomeric half mask and canister of respirator of long-term protection. To develop the models for theoretical calculations of protective properties of dust masks the theory of non-stationary filtration and hydro aerodynamics was applied. To develop the digital model of a head the downhill simplex method was applied reflecting separate face features considering sex or age; to determine the halfmask surface the free energy equation for bowed plate being described by two-dimension spline surface was used with its unknown coefficients determined by method of proportional parts based on three-dimension coordinates of anthropometric face features. The main anthropometric face features influencing halfmasks design were determined to develop polygonous 3D model of head. According to its determined basic coordinates the surface of halfmask was determined using method of interpolation. Considering the mathematical model describing the movement of dust flows near a halfmask and in canister the dependences of distribution of air flow speed in a canister of variable geometry were set and kinematic parameters of dust-laden airflow according to a canister volume were determined. Reasonable geometric parameters of canister were determined; transient modulation from filter to inlet valve hole is performed as a contractor

Improvement of the procedure of new filter masks development

The purpose is to substantiate theoretically the design of elastomeric half mask and canister of respirator of long-term protection. To develop the models for theoretical calculations of protective properties of dust masks the theory of non-stationary filtration and hydro aerodynamics was applied. To develop the digital model of a head the downhill simplex method was applied reflecting separate face features considering sex or age; to determine the halfmask surface the free energy equation for bowed plate being described by two-dimension spline surface was used with its unknown coefficients determined by method of proportional parts based on three-dimension coordinates of anthropometric face features. The main anthropometric face features influencing halfmasks design were determined to develop polygonous 3D model of head. According to its determined basic coordinates the surface of halfmask was determined using method of interpolation. Considering the mathematical model describing the movement of dust flows near a halfmask and in canister the dependences of distribution of air flow speed in a canister of variable geometry were set and kinematic parameters of dust-laden airflow according to a canister volume were determined. Reasonable geometric parameters of canister were determined; transient modulation from filter to inlet valve hole is performed as a contractor

UTJECAJ ELASTIČNOSTI REMENA ZA GLAVU NA ZAŠTITNA SVOJSTVA FILTRIRAJUĆE RESPIRATORNE ZAŠTITNE MASKE

The level of occupational respiratory diseases among workers in the mining, machine-building and metallurgical industries remains high. The most common occupational respiratory disease is pneumoconiosis, which is the result of the long-term inhalation of dust. It is possible to minimize the impact of dust on the workers and eliminate such diseases in the future due to the use of filtering mask respirators designed to reduce dust infiltration into the space under the mask. For this purpose, the choice of the type of elastic bands of filtering mask respirators has been substantiated by the geometric shape and tension forces that can ensure a permissible level of leakage of contaminated air into the breathing zone of the respirator during its use. A mathematical model has been developed to describe the influence of parameters of elastomeric headgear on the protective properties of the respirator. The dependence of the change in the residual tensile strength of the elastic bands of the headband has been established, and the dependence of the volume of air suction on the area of the elastic straps at the corresponding tension force has been determined. Using the model, the dependence of the volume of polluted air inflow on the area of the elastic straps at the corresponding tension force has been estimated. The design of the innovative inserts has been offered, which makes it possible to control the tension of the elastomeric head straps of the respirator to visualize the weakening of the pressure forces responsible for maintaining a tight fit.Još uvijek je prisutna visoka razina profesionalnih bolesti dišnoga sustava među radnicima u rudarstvu, strojogradnji i metalurškoj industriji. Najčešća profesionalna bolest dišnoga sustava jest pneumokonioza koja je posljedica dugotrajnoga udisanja prašine. Moguće je smanjiti utjecaj prašine na radnike i eliminirati takve bolesti pomoću filtracijskih respiratora koji smanjuju prodiranje prašine u prostor ispod maske. U svrhu poboljšanja uporabe respiratora istraživan je izbor vrste elastičnih traka filtrirajuće maske na temelju geometrijskoga oblika i sila napetosti koje mogu osigurati dopuštenu razinu propuštanja kontaminiranoga zraka u zonu disanja. Razvijen je matematički model za opis utjecaja parametara izolacijskoga pokrivala za glavu na zaštitna svojstva respiratora. Utvrđena je ovisnost promjene rezidualne vlačne čvrstoće elastičnih traka za glavu te je određena ovisnost volumena usisa zraka o površini elastičnih traka pri odgovarajućoj sili zatezanja. Pomoću modela procijenjena je ovisnost volumena dotoka onečišćenoga zraka o površini elastičnih traka pri odgovarajućoj sili zatezanja. Ponuđen je dizajn inovativnih umetaka koji omogućuje kontrolu napetosti remena za glavu respiratora kako bi se signaliziralo slabljenje sila pritiska odgovornih za održavanje čvrstoga prianjanja