The Oil-in-Water Test Sensor's Fluid State Research

The oily water not only pollutes water environment, also disserves human's life. So it is very meaningful to test the oil-in-water ratio quickly and accurately. This dissertation researched the oily water's fluid state. The fluid state influences test data's stability and accuracy. Firstly, this dissertation stated the technology status of near infrared spectrum and oil-in-water test apparatus. Then dissertation analyzed these apparatus's shortcomings. Some questions were given out, which can instruct the research work. Founded on the optical property of measured substance (a mixture of water and oil), a transmission measurement method is adopted in this paper. In the design of the pipe, the stability of current is taken as design rule since the experiment proved that the movement state of liquid has an obvious effect on the stability of the incepted signal. On condition that the water is laminar flow, the relationship between the diameter (d) of the in-pipe and the velocity of flow (V) is discussed through the calculation by means of Renault Formula. On the important problem of the choice of light source and light-sense incepting organ, the optimal matching on peak value wavelengths of light source, light-sense incepting organ and the measured substance (the hydrocarbon) is taken into account. In addition, the paper analyzes the liquid movement by using the software ANSYS (FLOTRAN) in order to know the movement state of the measured current. The data processing is done on the basis of former work; the digital filtering algorithm is introduced because of the lack of the consideration on random interference in the prophase of data collection. It is the key of the paper to design a type of detecting structure, which can avoid being contaminated by smeary oil, so that the on-line test of oil content in the wastewater can be realized in deed. The contamination of detecting structure has been a difficult problem to solve for a long time, although the structure design in the paper is still to be improved, it can provide...