透射光补偿浊度测量方法的研究

A new turbidity measurement method with compensation of transmitted light

设计了一种新型透射光补偿法浊度测量系统,介绍了测量系统的工作原理和探头结构。测量系统采用ISO7027国际标准规定的880 nm红外LED作为光源,以单片机ATmega128为核心,利用GPIB卡记录电压、温度数据。该测量体系通过同时测量水样散射光和透射光的方法,在低浊度时(<25 NTU)测量散射光,高浊度时通过量程切换并利用散射-透射光之比进行浊度测量,还设计了温度补偿系统测量浊度与温度之间的关系。配置福尔马肼标准溶液进行多点测试,结果表明本套测量系统测量浊度线性度高,数据稳定可靠。

A new type of turbidity measuring system with transmitted light compensation has been designed.The working principle and the structure of the measuring system are described.An 880 nm infrared light-emitting diode（LED） which is specified by the ISO7027 international standard was used as light source.An ATmega128 microcontroller was the core of this measuring system.The voltage and temperature were recorded by a General Purpose Interface Bus（GPIB） card.The scattered light and transmitted light of water samples were measured simultaneously.The scattered light was measured at low turbidity（25 NTU）,while the ratio of the scattered light to the transmitted light was measured at high turbidity.The relationship between the turbidity and the temperature was found and the accurate turbidity value was obtained by temperature compensation.Any impact of the aging of electronic components and variety of light source in the turbidity measurements was eliminated.A formazine standard solution was prepared for multi-point tests.The results showed good linearity of the turbidity measurements and the high stability of this measuring system.