Critical Valve Exercising
Critical valves are usually larger than standard reticulation valves (<250mm) and are typically installed on distribution pipelines. Critical valves are rarely operated but, should the need for their use arise, the reliance upon them to operate correctly is extremely high. As these valves are rarely used, debris (tuberculation, mineral deposits etc.) can build up on the valve’s moving parts and seal/seat sections. This can result in valves which are inoperable or hard to operate and, once shut, do not completely hydraulically isolate the section of reticulation that they are required to.
Most water providers realise the need for regular valve exercising of all reticulation valves, including critical valves, to increase the longevity of the valves and to ensure that the valves work correctly. This is typically undertaken by maintenance staff that partially operate valves with a valve key. A record is then made.
Detection Services has developed a number of dedicated vehicle mounted valve exercising systems. The main components of the system are a computer controlled, hydraulically driven exercising arm with inbuilt GPS fixing technology and a hydro/vacuum unit to remove and clear debris from valve chambers if required. All aspects of valve maintenance activities are electronically recorded and the resulting data is exported to the client. This data can then be imported into the client’s GIS (or equivalent) system and provides a detailed asset report and condition assessment rating for each valve exercised.
Detection Services’ vehicle mounted valve exercising system has a computer controlled hydraulically driven exercising arm as shown in the image below.
The hydraulic arm has the ability to deliver 750 lbft (1016 Nm) of torque directly to the valve requiring exercising.
This amount of torque is not usually required for standard valve exercising but can be used if required to free stuck valves.