Surge: causes, analysis and prevention methods

Summary

Engineers busy with designing pumping units are well familiar with the terms «hydraulic hammer», «pressure jump» or «surge» (shock wave) related to water. The problem is how at the designing stage to take into account the risks of surge occurrence and take necessary measures in time to prevent or minimize devastating consequences which is a challenging issue. As applied to the long water mains of large diameter, the damage caused by a pressure wave can be quite considerable, whereas eliminating the consequences involves considerable costs. The owners or operators of the pipelines subjected to the surge reluctantly provide the information on the damages caused by this phenomenon. That is why during designing the standard calculations are made and standard measures of surge prevention are suggested that do not take into account the negative experience of similar projects and the measures that were taken to prevent any further pressure jumps. In the given article the general theoretic notions related to the surge phenomenon and the methods of calculation are considered, the analysis of the surge is presented carried out by the experts of KSB company by the example pressure pipelines of a certain project the name and identification data of which are hold confidential. The given example describes in detail the encountered problem onsite and measures taken to solve it. The calculations, diagrams and charts are presented that show the differences between the system protected from the surge and the system not protected from this phenomenon.

Key words

pipeline system , surge , Zhukovski equation , surge analysis , surge protection , designing water supply systems and sewers

Measures for reducing the probability of damages in water distribution networks

Summary

Measures for reducing the probability of damages in water distribution networks under certain technological operating conditions are considered. The experience of using a valve that prevents water surge in combination with a pressure relief valve is presented. Installing a valve that prevents water surge in the pressure manifold of pumping stations provides for the effective protection against damages of pressure water conduits in case of a sudden stop of pumps, as well as in case of a sharp uncontrolled pressure increase in them. Analyzing the operation of a multifunctional water surge protection valve with the remote control and function of maintaining the set pressure upstream proved a smoother pressure change at the outlet of the booster pumping station, as well as smaller deviations of the actual value from the set value as the volume of process water supplied changes. It is shown that the equipment is effective in the absence of variable speed control units, as well as in emergency situations.

Key words

water supply networks , pressure reducing valve , surge protection , surge protection valve