HOW REDUCING WATER PRESSURE WITH CLEVER LOW MAINTENANCE VALVES CAN HELP FIGHT SOUTHERN AFRICA’S WATER SHORTAGES
Leaks are a part of every water supply system in the world but in southern Africa, the losses pose a threat to future water security.
With three years of drought having a devastating effect on water levels in South Africa most of the country has faced some restrictions in recent months.
And in Cape Town real dam levels are at just 12 per cent in some places and the authorities are set to implement an upgraded ban on external drinking water supply within weeks.
Reducing the pressure, especially during low demand can offer huge savings, visitors to INDUTEC Live 2017 were told yesterday.
PVP Live has offered expert insights into the pumps, valves and pipes industry affecting a wide range of liquids and gasses.
But protecting drinking supplies is a vital part of future development and the pressure reduction system would have real benefits across the country.
Peter Telle, of Ultra Control Valves, explained in simple language how pressure can be reduced in three different ways.
Pressure reducing valves (PRV) are the natural choice but can only really operate at a 3:1 ratio (reducing pressure for example from 12 bar to 4), but sometimes that’s not enough, he explained.
He said there are four or five brands on sale in South Africa, some operate by a timer, others by detecting changes in demand. They cost around Rand 50,000 ($3,700) but they are maintenance intensive and he said “too complicated for African conditions”.
“When the automated valve starts playing up, often engineers simply disconnect them, which is a costly loss,” he said.
He explained to the delegates how to increase the reduction in pressure above the 3:1 ratio, PRVs can be run in series, theoretically offering 9x reduction in pressure.
“But that can encourage cavitation,” he said. A hugely pump damaging effect of the two working against each other.
A simpler system could work well in Africa to reduce water loss through leaks and he showed the audience a new acquired ratio valve (ARV) with no controls and a Maric flow valve, which is able to operate with soiled water.
He showed how successful they operated in large buildings, ensuring adequate water flow but offering huge savings rom hi-raise buildings and hotels, through to streets.
Tomorrows conference session at INDUTEC 2017, called WaterTec 2017, is focused totally on water supply and anyone can attend though places are limited.