Effective Valve closure Time: The period over which a Valve reduces the flow from 90% of its steady state to zero.
When a surge relief valve opens, it vents the pressure to a safety system. A pressure surge normally consists of multiple events, resulting in up to ten times the normal pipeline pressure.Pressure Surge (pressure rise) increases as the pipeline straight length increases since the contained momentum within two direction changes (elbows/Tee) will be higher (more volume).Some pipelines are in transient operations over 75% of the time.Pressure Surges can occur in open channels and partly liquid-filled pipes, as wellĪll of the above causes will generate high pressure waves that can travel both upstream and downstream from point of origin.Presence of Air pockets inside piping/ pipeline systems, especially during pump start.
Quick operation of Valve (Sudden closure/opening).Pump start & stop, specifically due to load shedding or sudden power failure.