INFLUENCE OF ACTUATOR PRESSURE ON ELECTRO-PNEUMATIC VALVE CLOSURE TIME AND PIPE PRESSURE RISE

Valves are an indispensable element of every pipeline system (water supply, hydro power plant etc.), and their control is of great importance for the proper functioning of the system. Ball, butterfly, globe, and needle valves are usually used as flow control valves in pressurized pipe systems. Closing the valve can lead to an increase/decrease of the pressure, or water hammer, which can cause significant problems in the system in case this pressure is not maintained within prescribed limits. Depending on the generated transient events and on the installed surge protection devices, extreme pressures may compromise the pipe system safety, operation, and performance. An adequate closing law and closing time may lead to lower maximum and higher minimum pressures and increase system safety. The aim of this paper is experimental investigation of the influence of actuator pressure (the valve closure is controlled by the valve actuator) on electro-pneumatically operated valve (EPV) closure time and pipe pressure rise/drop, based on experimental tests carried out on experimental setup for investigation of water hammer and its side effects, unsteady friction, cavitation, column separation and fluid structure interaction (FSI) at the Faculty of Mechanical Engineering in Podgorica. Experimental runs have been performed with different initial values of pressure in the upstream end high-pressurized tank and different values of actuator pressure. Some of the obtained results are presented and conclusions are given.