Design and test of a novel isolated compressed oxygen self-rescuer for coal mines

ZOU Xiaoxu

doi:10.13347/j.cnki.mkaq.20250664

Abstract：To address the oxygen supply issues of traditional coal mine isolated compressed oxygen self-rescuers which provide a fixed oxygen supply rate of 1.2 L/min,causing oxygen shortage during escape(oxygen demand 2.1 L/min)and oxygen waste during seated waiting(oxygen demand 0.5 L/min),as well as problems like easy failure of mechanical pressure indicators,inconvenience in replacing CO2 absorbents,and unreliable materials for key components,a novel compressed oxygen self-rescuer meeting the GB 24502-2023 Self-rescuer for Coal Mine standard has been designed.By optimizing the flow channel topology of pressure redu-cer,the oxygen supply rate can be dynamically adjusted between 0.5 L/min and 2.4 L/min to meet the oxygen demands of both es-cape and seated waiting modes,significantly enhancing the protection time and oxygen supply stability during seated waiting.A low-power and intrinsically safe digital pressure indicator for mining applications has been developed using a diffused silicon pressure sensor,resolving issues of elastic fatigue,nonlinear drift,and high failure rates associated with mechanical indicators.A modular and replaceable canister has been designed to enable the rapid replacement of CO2 absorbent within 10 seconds.A mathematical model for determining the required amount of CO2 absorbent was established based on the chemical reaction kinetics of Ca(OH)2 absorbing CO2.Additionally,key components such as the shell,oxygen cylinder,and breathing bag have been carefully selected.Experimental results demonstrate that under the rated protection time of 45 minutes,the self-rescuer achieves a seated protection time of over 135 minutes,with an O2 volume fraction of at least 46.5%,a peak CO2 volume fraction of 1.46%,a peak inhalation temperature of 41.1℃,and a total breathing resistance of no more than 1.2 kPa.In terms of oxygen supply performance,when the working pres-sure of oxygen cylinder is between 3 MPa and 20 MPa,the self-rescuer provides a constant oxygen supply of 2.3 L/min at a breath-ing rate of 35 L/min and 0.7 L/min at 10 L/min.Both automatic and manual supplemental oxygen supplies reach 70 L/min,with oxy-gen supply fluctuations not exceeding 0.1 L/min.The research findings have been applied in multiple self-rescuer manufacturing en-terprises and have passed the safety certification inspection based on GB 24502-2023 Self-rescuer for Coal Mine.