A Tried and True Method of Surge Control

Surge Control is vital to the design of water transmission systems. If surge control methods are not properly implemented, surge pressures can have devastating effects on pumps, valves, pipe fittings, or pipelines—sometimes causing line breaks and service interruptions. A hydraulic transient can be caused by any number of events that cause the flow in the pipeline to be disrupted, including starting and stopping of a pump, an instantaneous closure of a delivery valve or a power failure at a pump station. When a reflected surge wave reaches the pump station, it must be dissipated through some open flow path to a lower pressure region. Failure to dissipate this reflected surge wave will cause a sudden pressure rise, due to the conversion of kinetic energy to potential energy. If the momentum energy and pressure energy of the reflected wave is not relieved, high surge pressures will result. There are several accepted approaches to surge control in the water industry. Many pump stations rely on check valves to prevent water from back-flowing through the pump, requiring an open path through a surge anticipator valve, pressure relief valve, or a lateral to a surge accumulator tank to dissipate the energy. The purpose of this paper is to provide the background and details for a distinct surge control methodology developed by Logan Kerr, chairman of the ASME’s Hydraulic Division Water Hammer Committee from 1933 to 1956. This methodology was later adopted and put into practice by Lee Freese in the late 1960s and implemented on dozens of water transmission systems across Texas. The main difference in this surge control philosophy centers around allowing the water to backspin through the pump after a power failure and using an accumulator system to slowly close the pump control valve after several cycles of the surge wave have passed through the system. This paper will provide additional details of the surge control methodology and its key components.