Use of Pressure Reducing Valve for Preventing Pipeline Rupture: A Case Study

Author Name(s): Pranit S. Hunge, Khalid S.Ansari, Tripti B. Gupta, Charuta S. Waghmare
Author Email: guptatb@rknec.edu

Abstract

In the present work, hydraulic modelling is designed so as to prevent the damage or leakage of water distribution networks due to water hammer pressure by maintaining adequate pressure. In water supply systems, water is transported from one unit to another by means of pumping or by gravity or by combined pumping-gravity methods. For this purpose, various components like junctions, pipes, joints, pumps, valves, fittings and other appurtenances are used. To provide proper design discharge along with sufficient quantity, adequate pressures are maintained by designing effective hydraulic modelling. In order to prevent damage, rupture or bursting of pipelines due to water hammer pressure, pressure reducing valves (PRV) are considered. The sudden or gradual, opening or closure of valves are decided by considering the pressure that is to be maintained so as to allow the proper flow at outlet or consumer end. In the present case study for Akot, an attempt has been made on hydraulic modelling of water distribution networks. Designing and analysis are done by placing the pressure relief valves at different locations and flow are adjusted by pressure settings using trial and error methods.

Introduction

Water and wastewater discharges from different industries and from the surrounding cities or towns causes contamination of the receiving natural water bodies and thus causes water pollution in the environment [1].This same sources are most of the times used for drinking. So it is necessary to treat this water [2]. As these water is supplied through water distribution networks for drinking purpose and end use purpose by the city or town. The water supply scheme has a key component i.e pipeline network, a key component with a complex structure involving huge investment, its stability and reliability is the important factor. Maintaining public health is the main moto. In the pipeline network, when water flow from upstream side to downstream side with a larger head and greater velocity, bursting or rupture of pipes take place. If the velocity of flow is suddenly diminished, the pressure generated by the water will try to compress the water by stretching the pipe walls and frictional resistance to wave propagation. As the demand for water increases and at the same time the longer time for water transportation will be required. This leads to the elongation of the pipe with a huge elevation difference from the upstream side to the downstream side.

Conclusion

The hydraulic model of the Malthana zone is generated and calibrated in Water GEMS software. It was assessed for its adequacy in term of pressure setting at different nodes with and without PRV’s. Based on the analysis and while operating the network without PRVs, it is observed that the head from start to end is large, the pressure at some nodes is less than 20 m H2O. Secondly by replacing the smaller diameter pipes with larger diameter pipes, the results are not found to be satisfactory. In that condition water hammering and bursting of pipes can happen. While operating the network with PRVs, it is observed that instead of larger head from start to end, the pressure at nodes is controlled by pressure setting to maximum 5 m H2O. In that condition HDPE 6 kg/cm2 pipes withstand the pressures and flow velocities. Like this way, rupturing and bursting of pipes due to water hammer pressures can be avoided.

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