In this study a system for real-time analysis of some involving factors in the efficiency of gas-liquid separators is developed based on the weighing method. An ultrasonic atomizer generates water drops in a size range of 1-10 μm with the same frequency during the test. A cyclone separator is selected and effect of the developing flow rate and shape of the mini-riser as a part of connecting assembly to the cyclone separator is investigated. Further an efficient electrostatic precipitator (ESP) with outcome of single-phase airflow is employed in the downstream of the cyclone to separate remaining droplets and produce the same pressure loss during the test. Circular, triangular, rectangular and square cross section areas with the same hydraulic diameter of 14 mm were examined. The highest cyclone efficiency was recorded for the triangular and rectangular risers comparing to the circular riser at the same length and hydraulic diameter, so the connecting risers with corner could improve the separation efficiency. Copyright © 2013 by ASME.