Structural design and protective performance of an oronasal-separated dust respirator for coal mine based on optimized airflow organization

Conventional oronasal dust respirators used in underground coal mines suffer from large dead space,high breathing resistance,poor moisture expulsion,and inadequate wearing comfort under high -dust,high -labor -intensity,and long -duration working conditions. These limitations reduce respiratory protection safety and long-term wearing compliance. To address these issues,an oronasal-separated coal mine dust respirator is proposed with the objective of enhancing individual respiratory protection and long -term wearing compliance. The respirator adopts a dual -channel airflow configuration,with nasal inhalation and oral exhalation separated. This structural design reduces ineffective dead space and minimizes the risk of exhaled gas recirculation. In addition,modular construction,replaceable filter cartridges,ergonomically designed sealing pads,and interfaces for powered air supply and drinking functions are integrated to achieve integrated optimization of protection performance and functionality. Key performance indicators,including leakage rate,filtration efficiency,inhalation resistance,exhalation resistance,and dead space,were systematically tested and analyzed. The results show that the filtration efficiency for NaCl aerosols exceeded 99. 0% under both pre -treated and non-pre-treated conditions. Inhalation resistance was below 170 Pa,and exhalation resistance was below 150 Pa,both significantly lower than the specified limits. The dead space ratio was controlled to below 0. 3%,which is markedly superior to that of conventional oronasal respirators. The tatal inward leakage met the technical requirements for replaceable half-mask respirators. These results demonstrate that the oronasal-separated structure effectively improves internal airflow organization, substantially reduces carbon dioxide and moisture accumulation,and enhances breathing comfort and filtration stability. While meeting coal mine dust protection requirements,the proposed respirator is better suited for continuous medium- to high-intensity operations,showing strong engineering applicability and promising potential for practical deployment.