Pressure management has become a crucial tool to reduce water losses in pipe networks. It brings almost instant results at a relatively low cost. The theory is that if you reduce the pressure in a network to the lowest practical pressure:-
- The volume of water lost from existing leaks will be reduced.
- There is less likelihood of new leaks developing.
But, it’s not set-and-forget. Presures must be adjusted to match flow demands. Electronic pressure controllers do this in two ways:-
- Time modulated. You program the high and low demand periods into the controller. The controller allows for normal pressure during high demand periods. It lowers the pressure during the low demand periods.
- Flow modulated. Pressure is adjusted continuously based on flow. This is more expensive up front because it needs a flow meter in the PRV installation, but water savings are optimised.
Ultra Alpine Pressure Management
The Ultra Alpine Pressure Management solution is unique in that it allows either time or flow modulated pressure management. It is a totally self-contained system. It requires no external power source. It can be battery driven, or tap power from pressure reducing valves. Access to set or adjust the system can be done remotely.
Control valve selection for pressure management.
Any pressure management solution must take the control valve specifications into consideration. In particular pressure drop ratio and low-flow handling.
Pressure drop ratio.
All pressure reducing valves have some ratio between upstream and downstream pressure at which cavitaion will occur. For most valves it’s around 3:1. If the upstream pressure is 9 bar the valve is safe as long as the outlet pressure is above 3 bar.
So even though you might be able to reduce the pressure to 2.5 bar to reduce water loss, that would cause cavitation in the PRV. Cavitation leads to instability which could result in pipes breaking, the opposite of what we’re trying to achieve.
You could of course install two PRVs in series to handle the required pressure drop. But that’s expensive, complex and can also cause instability leading to pipe breaks.
An alternative is to use a valve that can handle a higher pressure drop ratio for example the Ultra Alpine ACV control valve. It can handle a 4:1 ratio which would allow for the downstream pressure in our example to be as low as 2.25 bar. Special trims are available to accommodate large ratios and lower flows in extreme cases.
Minimum flow rate.
There is a minimum flow rate below which all standard control valves become unstable, risking pipe breaks.
A second smaller valve could be installed in parallel to handle low flow during periods of low demand (e.g. the middle of the night). This is more complex than it needs to be. The Ultra Alpine control valve has special trims available to handle low flows without any additional complexity.
Ultra Control Valves offers three types of control valves that are well-suited for pressure management applications.
- The Ultra-Alpine ACV Diaphragm Operated control valve.
- The Ultra ACV Ratio Reducing valve.
- The Maric Flow Control valve.
The Ultra-Alpine ACV Diaphragm Operated control valve.
This valve is based on the well-regarded Cla-Val design. It offers an industry-leading 4:1 pressure drop ratio and a long design life. The valve is robust and the internals are easy to service. It also allows for different V-ports to solve cavitation and low-flow control.
The Ultra ACV Ratio Reducing valve.
This is the simplest pressure reducing valve. It has no pilots or moving parts. It has two use cases when using pressure management to reduce water loss:-
- As a simple pressure reducing valve. Install it where the pressure is higher than it needs to be and the reduction in pressure will result in reduced water loss.
- Upstream of a pressure reducing valve where the pressure drop ratio would lead to cavitation. Because it’s a passive device there is no risk of the instability you’d get if you installed two pilot operated valves in series.
The Maric Flow Control valve.
This Australian product has captured the water industry’s imagination as the ideal type of valve to control flow rates. It also serves as a water saving device when used in the correct applications.
Malmesbury Municipality in South Africa ran a pilot project using Maric flow control valves in areas where residential and commercial users were abusing water usage. The outcome was excellent with a significant reduction in water usage.
Introducing our water loss management service.
You probably know us as valve manufacturers and suppliers but we also offer a complete water loss management service. It includes:-
- Leak detection.
- Data logging.
- Network analysis and reporting on ways to minmise losses.
- Commissioning valves and associated installations.
- Field service.
It’s the sad truth that most of our water infrastructure is not maintained as well as it should be. Something as simple as having us inspect your pressure reducing valves regularly can have a huge impact on water saving – without needing any extra equipment.
If you’re concerned about water loss please contact the me and we can explore options together.