Microwave Sensor for Accurate Material Density Measurements of Gas/Solid flows in Pipelines

This paper presents a novel material density sensor based on two novel microstrip-patch (MSP) couplers for process monitoring applications. The sensor is designed to detect gas/solid flows, especially for very low solid concentrations without changing the flow distribution and the velocity profile in the pipeline. The couplers exhibit low insertion losses and distinct transmission maxima that extent a high sensitivity of the sensor system. Measurement errors below plusmn2.5% relating to the instantaneous value could be archived for solid concentrations from 0.064% (vol.) up to 0.25% (vol.) (Penirschke and Jakoby, 2006). The investigation of the measurement errors shows that the sensor accuracy can be increased still further by a reduction of the temperature influence to the sensor