The oil in water analyzer developed and produced by Erun Group is a water oil concentration testing instrument using the national standard HJ637 infrared photometry principle, which can be used to quickly analysis the concentration of oil in water. The oil concentration tester uses infrared light of different wavelengths and the intensity of light absorbed or scattered by oil molecules in the sample to determine the oil content, which can be applied to the rapid testing of oil concentration in industrial process water such as boiler water, circulating cooling water, or surface water, groundwater, sewage, wastewater and other water.