Measurement of deionized water density based on single silicon sphere

Due to perfect stability, deionized water is usually used as one important reference material for density and volume calibration. To evaluate suitability of pure water density formulas for deionized water, one measurement system based on Archimedes’s principle was designed, and silicon ring was used for density standard to measure the density of deionized at 20°C. The experimental result shows that The Tanaka equation can be used to calculate the density of deionized water with deviation 5ppm. The uncertainty budget of measurement is analyzed, and the combined relative uncertainty is 4.09ppm (k=2).