MODIFIED TDR METHOD AND APPARATUS FOR SUSPENDED SOLID CONCENTRATION MEASUREMENT

Abstract

This invention utilizes the principle of time domain reflectometry (TDR) to develop an improved apparatus and method for suspended solid concentration (SSC) measurement. The apparatus comprises a TDR sensing waveguide for stably determining an electromagnetic-wave (EM-wave) travel time and a temperature sensor. The TDR sensing waveguide and the temperature sensor are submerged in a suspension to detect the EM-wave travel time and the temperature. A temperature-corrected relationship between EM-wave travel time and SSC is found and used to estimate the SSC. Although TDR has been used for measuring soil moisture content and high SSC, its accuracy is not satisfactory for typical SSC monitoring. The present invention improves the accuracy of TDR in SSC measurement by providing the apparatus and method disclosed herein, which are not affected by an electrical conductivity of the suspension and particle sizes of suspended solids therein, and therefore meet the requirements of general engineering applications and environmental monitoring.