Performance of a pumped discharge line with combined application of protection devices against water hammer

This study investigates the performance of a pumped discharge line with joint use of protective devices against water hammer expected to occur due to sudden stoppage of pumps. To this end, a pumped discharge line planned to be constructed is considered for hydraulic transients generated subsequent to pump trips. The unprotected form of the system is found to experience very low pressures below the vapor pressure of the liquid. Then single and combined application of flywheel, air chamber and in-line check valves are proposed and checked for their effectiveness in protecting the system. Single use of those devices is found to be insufficient and expensive, whereas the joint application of the in-line check valves and the air chamber are shown to be economical and successful in protecting the pipeline. Combined use of in-line check valves and air chamber is found to reduce the volume of the chamber by 65%, which also reduces the total cost of the protective measure by approximately 50%.