针对常用光学浊度测量方法容易受背景光影响引起测量误差的问题, 提出了一种基于偏振光的垂直散射式浊度测量方案。利用偏振片的起偏和检偏功能, 实现偏振光的产生与检测, 有效地降低了背景光带来的测量误差。运用低漂移、低噪声的高性能运放电路实现电路系统的驱动与信号处理, 提高浊度的测量精度。实验结果显示, 在不同的背景光条件下, 该浊度仪能够准确测量0~400 NTU浊度范围内的待测溶液的浊度, 且测量精度在5%F.S以内, 表明该浊度仪具有较强的抗干扰能力。

An optical turbidity meter based on the vertical polarization light scattering measurement scheme was proposed to reduce the influence caused by the background light. The polarization light was generated by using a polarizer after the normal light source and the other polarizer were placed before the detector to reduce the measurement error. A high performance operational amplifier circuit with low temperature drift and low noise was used to drive the light source and for signal processing, which can dramatically increase the turbidity measurement accuracy. Experimental results show that the turbidity meter can accurately measure the turbidity of the solution within the test range of 0~400 NTU with the measurement error less than 5%F.S under different ambient light conditions, showing its strong ability of anti-interference .