عنوان مقاله [English]
Actuators with line-break detection system can be used in the zones with no access to national electricity network, hazardous or impassable area enclosure, for passive defense conditions or to protect different ecosystems such as rivers and ground water, forests and fertile land and etc. In this paper, the effects of orifice diameter, pipeline initial pressure and pipeline pressure drop rate on the setting differential pressure in a quarter turn Scotch-Yoke actuator have been studied by 81 tests. The nitrogen gas was used in this experimental study. The actuator differential pressure is increased by the growth of pipeline pressure drop rate or reduction of orifice diameter or pipeline initial pressure. The occurrence time of maximum differential pressure of diaphragm valve depends just on orifice diameter. This time is independent of pipeline pressure drop rate or pipeline initial pressure. It increases with the decrease of orifice diameter. The curves of actuator differential pressure which is generated by different pipeline pressure drop rates are proposed for different pipeline initial pressures and orifice diameters. The values of curves in this diagram with 10 percent safety factor can be used in differential pressure value setting of quarter-turn actuator installed on gas transportation pipelines.