Reducing the water hammering, surges, and slamming caused by check valve closure in a wastewater pumping station by using a swing flex check valve

Abstract

Water hammer is one of the most dangerous phenomena in liquid or liquid/gas systems, because it can cause failure of the system integrity. Sudden valve closure in pipeline systems can cause high pressure that may lead to serious damages. Using an optimal valve closing rule can play an important role in managing extreme pressure in sudden valve closure. Many studies for water hammer concentrated on the main pipeline and pump stopping and important details can be overlooked. Air reduces wave celerity but increasing of surging can occur with some pipework configurations, particularly if air can be trapped, Pump startup can then result in severe water hammer. Selection of a proper check valve for a pumping station is essential to avoid vibration, noise, slamming, and pressure surge problems for the pipeline and pumps. So, in this paper two different check valves were tested for a sewage pumping station: a swing check valve and a swing flex check valve. Pressure measurements were recorded for both cases after a pump trip and resulting check valve closure. Surge analysis using a commercial software (Bentley Water Hammer) was performed. The experimental data was compared for predictions from the model. There is a good agreement between the experimental and predicted data. The results showed that the maximum transient pressure due to the swing flex check valve closure was 33.3 % less than using traditional swing check valve. Accordingly, it is recommended to use this type of valves in sewage water plants because of their high performance during pressure surges. The swing flex chack valve also achieved less slamming during sudden stop pump, so, it can be classified as a non slam check valve.