Communications on Hydraulic and Geotechnical Engineering. An Improved Settling Tube System for Sand

摘要

General design aspects of settling tube systems for fall velocity analysis of sand are reviewed, with emphasize being placed on detection methods for particle arrival at the lower end of the settling column and the various sources of errors. This is followed by a detailed discussion on the development of an improved settling tube system employing an underwater balance. In order to achieve a high degree of accuracy, stability and damping, the weighing system includes a feedback mechanism which consists of a solenoid-magnet unit and a differentiator this yields a resolution of 10 micro N.