Development Of A Multifunctional Apparatus For Fast Measuring Viscosity Surface Tension And Density Of Normal Temperature Liquid

Viscosity, density and surface tension are significant physical property parameters of liquid, which are very important experimental parameters criteria of evaluating liquid quality in petrochemical industry and medicine domain. So it is vital practical significance to develop novel instrument of fast measuring viscosity, density and surface tension.In this paper, the present situation and the developing tendency of viscosity, density and surface tension speedy tester of normal temperature liquid are summarized and the testing principle of multifunctional apparatus and the mechanism design are discussed. The method of hardware and software design is also detailed. In the testing device the liquid density is measured by the static weighing method and the viscosity is measured by revolved cylinder method. A new method, Amplitude and Frequency Equivalent of Bubbles, is used to measure the surface tension. The new method for fast testing surface tension of normal liquid is developed based on maximum bubble pressure method and the principle of which is to calculate liquid surface tension according to the pressure difference in a bubble and the number of bubbles which are blown into liquid within fixed period.The multifunctional testing device which is made up of the multifunctional probe head, the weight unit, the air feeding unit, the data acquisition and processing unit and so on has the merits of compact structure, reasonable layout, small volume and multi-parameters measurement. To meet the requirement of installing mechanism, the capacitance sensor which may measure viscosity of low viscous liquid is developed by author. On the core of 80C196KC, by extending ROM, RAM, I/O interface circuit and analog signal processing circuit, the measuring apparatus has realized the synthetic measurement of normal temperature liquid parameters, by using which the information parameters including the air pressure, the measuring sample weight and revolving resistance can be gathered and the results such as viscosity, density and surface tension of liquid can be displayed and printed automatically.