The Research Of Technology On Turbidity Sensor Used In Deep Sea And Signal Processing

Putting all kinds of sensors and its integrated system into deep sea directly to detect the deep-sea environment by suspending from the ship, which can show the real information of deep-sea environment to some degree has been an important method on the research of deep sea, because of its field test and cheap cost, short work terms and its sending the data to the board of the ship in real time.The research and design of the turbidity sensor is very important, because the value of the water in the sea is bigger around the hydrothermal fluid vent.According to the subject's task, we choose the scattering light method after comparing some kinds of methods of detecting turbidity. And we choose photodiode as light detecter after comparing the capability of photodiode, photoconductive resistance and silicon photocell. Because the signal of the detecter which receives the light scattered by the particulates in water is very small, we choose phase-locked loop and phase sensitive demodulation circuit to process the small signal.We design the circuit according to the require of deep-sea turbidity sensor's high sensitive by eliminating the interference of natural light and "dark" current.Sensor encapsulation includes the design of pressure-resistant shell, transparent windows and seal. The encapsulation of sensor should be small and light without influencing the sensitive of the sensor.Turbidity sensor is integrated the in the system, which is used in analyzing hydrothermal sulphide. And realize data collection and storage.At last, we have done turbidity sensor lab experiment and the system ocean experiment. We compared the capability between the turbidity sensor we design and the commercial turbidity sensor. The result of system ocean experiment proves that the system we design can implement the detecting of hydrothermal sulphide in the deep-sea.