Turbidity is an important indicator of water quality. In order to measure turbidity quickly and accurately, a portable immersion turbidimeter is designed. Turbidimeter is based on the transmission light method. The light source uses a 850 nm small power laser tube with a photodiode (PD). The laser tube generates 1 kHz modulated light beam under the control of the transmitting circuit, and PD is used to keep the luminous intensity constant. The optical receiver circuit uses PD BPW82 to receive the beam passing through the sample, and adopts the DC recovery circuit to eliminate the low frequency background light interference. The voltage signal representing turbidity is extracted from the modulation signal through the precise rectification circuit and the filter circuit. The software simplifies the design of the circuit by using the computing power of the microprocessor and saves the logarithmic amplifier. The proposed calibration algorithm and floating-point storage method to detect liquid content of zooplankton in the system adopts the double light path structure of the measured liquid and liquid reference standard sample, the photoelectric turbidity measurement device of a direct type design, the hardware circuit includes signal detection processing module, signal processing module, MCU data processing module and liquid crystal display module. The calibration system after the debugging, the measuring result is stable, linear error is less than 1%. Its principle is that when the light hits the surface incident light intensity of transmitted light scattering intensity between each other and there is some correlation between the ratio and the turbidity of water sample were determined by the ratio of determination of intensity of transmitted light scattering intensity and the incident intensity or intensity of transmission and scattering intensity to the. The turbidimeter is used in the laboratory and is used for the automatic continuous determination of the turbidimeter.
Atmospheric aerosols have a very important impact on climate, visibility and the formation of clouds; at the same time, it also causes many harm to human health. The research on the basic characteristics of aerosols contributes to the formation mechanism of aerosol, and can provide an effective solution for the prevention and control of aerosol pollution. As an important parameter of aerosol, scattering coefficient can provide important information for chemical composition research and particle size distribution of aerosol. At the same time, scattering coefficient can be used to retrieve visibility. At present, the main method for measuring the scattering coefficient of the commonly used sampling and non sampling method, the optical scattering method with high accuracy and can continuously measure and other advantages and is widely used in the design introduces a geometric structures based on the coefficients of the global scattering measurement of turbidity integral system. On the basis of the deep analysis of the measuring principle and calibration method of the integrated turbidimeter measurement system, the overall scheme of the system is completed. The system is mainly divided into three subsystems: optical path, gas circuit and control circuit. The main tasks are control circuit hardware design and debugging, control software compilation, data communication and processing. The light source system through the LED constant current drive circuit to ensure the stability of the LED light source emitting photon; high speed pulse counting circuit used to achieve accurate detection of weak scattering light signal; the switch control circuit to achieve control of gas path components; circuit for measuring environmental parameters to realize the measurement of the ambient temperature, humidity and air pressure; asynchronous serial communication circuit to realize storage of scattering light signal count is uploaded to the PC; the keyboard and LCD display circuit used to achieve human-computer interaction. In the experiment, the light intensity distribution was tested by comparison with the ideal Lambertian light intensity distribution function, the light source of the system basically meet the Lambertian distribution conditions; combination of light time linearity and stability test, verify the rationality of the light source module driver. The uncertainty of the system is theoretically analyzed from three aspects: the uncertainty of standard gas, the influence of water vapor and the uncertainty of counting. Finally, the system is calibrated, and the data measured by the wavelength 530nm light source are compared with the visibility meter. The trend is the same. The data correlation is 0.89, which validates the feasibility and reliability of the system. In view of the above analysis, it is generally applicable to the following turbidity meters: scattering optical transmission and transmission light scattering. This article introduces the on-line turbidity analyzer: Online turbidity analyzer built-in microprocessor, advanced configuration, powerful, is the turbidimeter very sophisticated infrared light source based on 880nm scattering through the optical lens and penetrate the sample liquid according to the standard of ISO7027 measuring 90 degrees direction of the optical principle of this analyzer can be used to measure the turbidity of raw water or pure water filtration device in different where the local drinking water turbidity as the product structure of production and industrial water and no need to use qualified water compact built-in backlit LCD screen memory data relay control output 3 turbidity controller outputs a 4~20mA signal for any local isolation transmission monitoring and control the turbidity of reliable data.