The City of Cape Town has bought four valve exercising machines – the first in Africa – from US valve maintenance products manufacturer EH Wachs to perform maintenance on the 175 000 valves contained in its 10 000-km-long water reticulation network, reports City of Cape Town Water and Sanitation Department utility services manager John Potgieter.

These valves are used to isolate parts of the system to allow for construction, maintenance or repairs to be done to the network. The global positioning system (GPS) featured in the exercising machines makes it possible for location data, additional maintenance, repair and life cycle information, to be loaded onto the city’s geographic information systems, which enables the city to improve maintenance schedules and validate asset registers.

The GPS plotting device also allows for the position of individual valves to be accurately mapped during maintenance, which is helpful to maintenance teams who might need to find the valves that need attention, especially in difficult conditions.

Meanwhile, EH Wachs has been providing the global mining industry with self-powered valve maintenance trailers and truck-mounted machines, used to maintain valves, since 2008.

The machines have automation and microprocessor handheld controllers to allow for hands-free operation.
The trailers are designed to transport valve maintenance tools needed at mine sites. They are customisable and can be upgraded to suit increasingly demanding operational conditions.

Need for Maintenance
EH Wachs details that valves and valve hand-wheels need to be turned periodically to prevent them from freezing or getting stuck. Further, valves can seize up due to corrosion if they are not used frequently. To prevent these malfunctions from taking place, valves must be exercised.

Exercising a valve is a process that involves running it through its full operating cycle to prevent sticking, freezing or tuberculation – the formation of small mounds of corrosion on steel or iron.

Large manually operated valves typically require a significant amount of revolutions to fully cycle from an open position to a closed position. Further, turning large valves and valve hand-wheels is arduous and poses a danger to operators, who risk injuring their arms and backs, and sustaining repetitive stress injuries.

How it Works
Valve exercising machines perform maintenance mechanically, eliminating the need for operators to turn valves by hand. EH Wachs valve exercising machines are boom-mounted and diesel-powered and have torque control, enabling them to cycle the valves mechanically.

The trailers carry pumps and spoils displacement containers, as well as power washing equipment. They also have space to accommodate all the tools and spares needed to carry out maintenance, repair or replace the valves.