دياگرام بدون‌بُعد دامنه كاركرد شيرهاي كنترلي اتوماتيك شكست خط انتقال گاز

The non-dimensional diagram of automatic line-break control valve performance domain in gas transportation pipeline

شيرهاي كنترلي اتوماتيك شكست خط به دلايل متعدد در مناطق صعب العبور و با توجه به نياز پدافندي غيرعامل يا حفاظت از اكوسيستم روي خطوط انتقال گاز نصب مي‌گردند. اثر مشخصه‌هاي قطر اوريفيس، فشار اوليه خط و نرخ افت فشار شكست خط بر اختلاف فشار تنظيمي شير بصورت آزمايشگاهي با گاز نيتروژن بررسي شد. با افزايش نرخ افت فشار شكست يا كاهش قطر اوريفيس يا فشار اوليه خط، اين اختلاف فشار افزايش مي‌يابد. زمان دست‌يابي به اختلاف فشار تنظيمي، تخمين ‌زده شد. دياگرام اختلاف فشار تنظيمي بدون‌بعد برحسب نرخ افت فشار بدون‌بعد در دامنه كاركرد شير كنترلي اتوماتيك ارائه شد.

The effects of orifice diameter, pipeline initial pressure and pressure drop rate due to rupture on the differential pressure of diaphragm valve in a automatic line-break control valve have been studied by experiments. The fluid in this experimental investigation was nitrogen. The reference tank is connected to the pipeline through a calibrated orifice with check valve. The tank pressure is higher than pipeline pressure when pressure reduction occurs by line breaking. If the pressure difference between tank and pipeline is higher than the sustainable pressure value of diaphragm valve, the valve will be closed by actuator. The differential pressure of diaphragm valve is increased by the growth of pipeline pressure drop rate. The occurrence time of maximum differential pressure of diaphragm valve just depends on the orifice diameter. The maximum of differential pressure increases with the decrease of orifice diameter. The setting differential pressure of control valve was increased by decrease of pipeline initial pressure or orifice diameter or increase of pressure drop rate. The curves of non-dimensional maximum differential pressure generated by non-dimensional pipeline pressure drop rates are shown for different orifice diameters and pipeline initial pressure. These important curves will be used for design and setting of these automatic line-break control valve operation.