Development of a new respirator for organic vapors with a built-in breakthrough detector using semiconductor gas sensors.

要预测工作人员戴着口罩时有机蒸汽的突破通常是困难的，因为有机蒸汽的使用寿命取决于许多因素，如蒸汽的种类、浓度、温度、相对湿度和呼吸速率。本研究提出了一种测定呼吸器防护罩内蒸气是否突破的方法。将含有有机蒸气的空气引入滤筒，利用配备火焰电离检测器的气相色谱仪测量呼吸器下游的蒸气浓度，得到突破曲线。同时，插在墨盒下游的半导体传感器的输出信号被暂时记录在IC卡中。测量结束后，将卡上记录的数据传输到个人计算机上，并将传感器输出信号的变化与GC得到的突破曲线进行比较。对芳香烃、氯化烃、乙酸酯、醇类、酮类和脂肪烃等8种溶剂进行了测试。传感器对氯代烃的灵敏度普遍较低，特别是在相对湿度较高时，但传感器信号的上升时间与气相色谱获得的突破时间几乎相同或更早。这些结果表明，该传感器可作为有机气体在呼吸器盒中的突破检测器。在此基础上，研制了一种带突破探测器的呼吸器，并对其可行性进行了讨论。

To predict the breakthrough of organic vapors in a respirator cartridge when a worker is wearing it is usually difficult because the service life of the cartridge for organic vapors depends on many factors, such as, the kinds of vapors, concentration, temperature, relative humidity and the respiratory rate. In this study, a method for determining the breakthrough of the vapors in the respirator cartridge was developed. Air containing organic vapors was introduced into the cartridge, and the breakthrough curve was obtained by measuring the vapor concentration at downstream of the respirator with a gas chromatograph (GC) equipped with a flame ionization detector. Simultaneously, an output signal from a semiconductor sensor that was inserted in the downstream of the cartridge was recorded in an IC card temporally. After the measurement, the data recorded in the card were transferred to a personal computer and the change in the output signal from the sensor was compared with the breakthrough curve obtained by the GC. More than eight kinds of solvents including aromatic hydrocarbons, chlorinated hydrocarbons, acetates, alcohols, ketones and aliphatic hydrocarbons were tested. The sensitivity of the sensor for chlorinated hydrocarbons was generally low, especially when the relative humidity was high, but the rising time of the signal from the sensor was almost the same as or earlier than the breakthrough time obtained by the GC. These results suggest that the sensor is applicable as a detector of the breakthrough in respirator cartridges for organic vapors. Based on the results, a respirator with a breakthrough detector was developed, and its availability was discussed.