传感器原理及应用第9章 半导体式传感器.ppt

* Wood drying is performed within huge halls with emmense stacks of wood. A high quantity of water is taken out of the wood: E.g 1000 kg of oak wood has to loose 500 liters of water in the course of the drying process. Relative humidity, temperature and duration vary depending on the wood involved and the specific process. Within a thermally insulated cell, the stacks of wood are exposed to an air stream, which is forced by fans (see outlets on photo!). An air cooler takes away condensate, and an air stream bypass helps to control the process. If drying is proceeded too quickly, the wood can loose its surface quality or bend and thus be of less value. This is why the process is to be undergone under precise relative humidity control. Because of the high humidity involved, a heated probe (Hygrotest 650 HP) is usually the best solution. * Ceramics and brick production are demanding drying processes. The bricks are put onto wagons and are sequentially treated in two dryers. The probes are usually inserted from the top and thus a cable/probe version is applied. As temperatures are high (in the main dryer), often high temperature versions such as H650 PHT180 are needed. With our condensation protection we have a good solution even for highest humidity conditions. 传感器原理及应用 第9章 半导体传感器 9.1 气敏传感器9.1.3 半导体气敏传感器应用 红外多种气体检测系统动画演示 红外吸收 (IR-process) 测量原理 CO2 CO2 气体 气体 IR-探测器 可吸收CO2的过滤器接口 IR-散热器 (lamp) 氧气传感器 (带 2 个电极) 电化学传感器 (2) 阳极 电离流动 电解溶液 阴极 连接电缆 阴极 NTC-resistor with negative TK 可渗入气体膜 外部电路 烟气 参考 电极 counter electrode 工作 电极 烟气 可渗入气体膜 可渗入气体膜 新鲜空气 电解溶液 sensor flow 外部电路 CO, SO2 or NOx传感器(3 electrodes) 电化学传感器 (3) 白金线 外壳为催化金属 热效率探测器 用于检测可燃气体 线圈温度升高 气体中氧气的燃烧率湿必须知道的! 使用于测量KW 白金线通过电流加热至约 500°C 受热或不受热的抽提探头 不同的探头材料 适用于不同温度范围的探头 带简单陶瓷过滤器的探头 探头清洁装置（根据类型） 抽提探头 烟气测量时，首先将气体抽入装置，抽提探头要过滤水分和颗粒物。一般抽气管加热100℃以上，避免取烟时管路被水凝结。 测量气体管 露点 冷凝 (4) 最大长度: 5 m PTFE-