Research On Detection Unit Of Liquid Composition Concentration Based On Optical Scattering Method

With the rapid development of our economy, the detection method of liquidcomposition varied, Which chemical analysis method for the GB, although thedetection accuracy, but the long cycle, complicated operation. At present, nearinfrared spectrum analysis method is used. However, this method is relatively lowdetection sensitivity and the error is large.Looking for the detection method is simple,accurate, low cost has been discussed.Firstly, this paper uses light scattering method for detection of liquidconcentration levels,which needs a stable laser source. The accuracy of test resultsdirectly determined by stability of the light source, Through the analysis of thefactors affecting the stability of laser light source, to know the main parametersaffecting the performance of lasers is the surge current and temperature change. Inview of two aspects, this paper research laser constant current driver and temperaturecontroller.adopted negative feedback technology.Second, Photoelectric high precision detection circuit needed. Through theresearch on the theory of photoelectric detection technology, optoelectronic interfacecircuit performance will directly affect the circuit detection SNR, this paper adoptedthe transimpedance preamplifier circuit as a connection detection circuit, the weaklight detection circuit designed. the amplifying and filtering technology.Finally, casein solution concentration were accurately determined, detectionprototype needed for shading with black velvet, avoid noise outside light sourceunwanted effects on test results. At the same time by near infrared spectrophotometryTJ270-60carries on the analysis to the casein solution and water, through thespectrum analysis, the casein solution concentration detection wavelengths requiredfor650nm. In addition, through the comparative analysis of experimental data on thesize and shape of the test plate are determined.The experimental results showed that: the laser driver circuit load adjustmentrate is1.27%, the current stability reach the order of10-6, the final realization of optical power stability within0.14%. Photoelectric detection circuit can detect morethan0.1μ W weak light detection circuit detects voltage deviation, the maximum is0.006. The best concentration of casein solution detection model optimized for0~6%.The liquid component detection unit based on light scattering method to meet thedesign requirements, and has certain practical significance.