T-junctions are often used as partial phase separator to separate two phases gas/liquid feedstock in industrial applications. T-junctions are typically positioned in such a way that two-phase flow entering the T-junction split unevenly between branch and run arm, leaving the gas-rich flow in branch arm and liquid-rich flow in run arm. The T-junctions used in industry are either regular (D3 = D1) or reduced (D3 < D1) T-junction. There is no design standard available for the design of T-junction. Often, excessive liquid carry-over occurs in the branch arm, resulting in the breakdown of downstream equipment which is not designed to handle excessive liquid. In this study, converging T-junction was designed, developed, and experimentally tested. Converging T-junction was designed with a combination of two diameters D3 and D4 in the feedstock. The diameter of the lower pipe D3 of the branch arm was kept larger than the diameter of the upper pipe D4. The motivation behind this converging T-junction was based on the analysis of previous experimental data on regular and reduced T-junction, where a large diameter ratio T-junction resulted in high gas threshold while small diameter ratio T-junction resulted in low peak liquid carry-over. Thus, a converging T-junction will likely possess the best characteristics of both large and small diameter ratio T-junction. Converging T-junction with combined diameter ratios (D3/D1, D4/D1) of (01, 0.52), (01, 0.20), (0.67, 0.52), (0.67, 0.27) and (0.5, 0.27) were experimentally tested in slug flow regime. The inlet conditions were: Pressure - atmospheric, temperature - 25 °C, superficial gas velocities 0.388 � JG1 � 0.620 m/s and superficial liquid velocities 0.252 � JL1 � 0.582 m/s. It was found that the proposed converging T-junction's geometry performed very well. The separation efficiency of 93 was achieved in case of stratified-wavy flow with not more than 20 of the max. liquid carry-over and above 88 in case of slug flow with less than 35 max. liquid carry-over. This new geometry increased separation efficiency of 5�25 in stratified-wavy and 20�35 in case of slug flow as compared with conventional T-junction. © 2019 Elsevier B.V.