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Under the specified test conditions, the time required for the emulsion formed by mixing the sample with the added water vapor or water to achieve complete separation (or when the emulsion layer is equal to or less than 3 ml as specified) is referred to as the demulsification time. So, how can we make the most of this time? Below, we will provide a detailed overview of the considerations related to the demulsification time, to help you obtain more accurate measurements when using it. I. It is important to note that distilled water should be clean, free of impurities, and neutral in pH; ordinary water cannot be used, as it contains various salts such as calcium salts and magnesium salts. The instrument should be cleaned thoroughly; if it is not clean, the demulsification time will increase. Second, when allowing the mixture to separate in a water bath, it is necessary to prevent the instrument from being subjected to vibrations, as vibrations will shorten the time required for demulsification. Third, the measuring cylinder must be installed firmly and vertically, and the stirrer must be positioned vertically and stably to ensure it does not touch the walls of the measuring cylinder. IV. During the measurement period, the height difference between the pressure gauge and the liquid level in the steam generator must remain constant. This is because the speed of the steam introduced affects the degree of emulsification, which in turn influences the measurement results. V. The test temperature must be controlled at 54°C ± 1°C or 82°C ± 1°C, with a constant temperature maintained. Because temperature affects the viscosity of the oil, which in turn influences the degree of emulsification and the emulsification time. Finally, pay attention to making the correct judgment of the results. A common mistake made by beginners is to start the stopwatch only after the individual bubbles at the water-oil interface have disappeared, which results in higher measurement values. As specified, as long as there is no complete emulsion layer between the oil layer and the water layer, and the meniscus interface between the water and oil layers appears clear when viewed from below, it is considered that the separation has been complete. There is no need to worry about the narrow emulsion ring at the water-oil interface, individual bubbles, or the turbidity of the water and oil layers.