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

当工人佩戴时，预测呼吸器滤筒中的有机蒸气的穿透通常是困难的，因为滤筒对于有机蒸气的使用寿命取决于许多因素，诸如蒸气的种类、浓度、温度、相对湿度和呼吸速率。在这项研究中，一种方法来确定呼吸器滤筒中的蒸汽的突破。将含有有机蒸气的空气引入滤筒中，并且通过用配备有火焰离子化检测器的气相色谱仪（GC）测量呼吸器下游的蒸气浓度来获得穿透曲线。同时，将来自插入盒下游的半导体传感器的输出信号暂时记录在IC卡中。测量后，将记录在卡中的数据传输到个人计算机中，并将来自传感器的输出信号的变化与通过GC获得的穿透曲线进行比较。测试了芳烃、氯代烃、乙酸酯、醇、酮和脂肪烃等八种以上的溶剂。该传感器对氯代烃的灵敏度一般较低，尤其是在相对湿度较高时，但传感器信号的上升时间几乎与GC获得的穿透时间相同或更早。这些结果表明，该传感器可用作有机蒸气呼吸器滤筒穿透的检测器。在此基础上，研制了一种带穿透探测器的呼吸器，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.