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How to Reduce Water Losses and Pipe Bursts?
3 VAG Solutions for effective Pressure Management
VAG offers three pressure reduction solutions to assist utilities to reduce water loss to sustainable economic levels. The VAG Plunger Valve can reduce system pressure using the following modes:
Each mode of operation offers different control characteristics and benefits which may be selected to meet budget and engineering requirements as discussed in the following text.
Time Based Modulation
This method is achieved by using a controller with an internal timer to change the set point of the fixed outlet control. Control is affected in timebands in accordance with demand profiles. Time based modulation is very effective for areas with stable demand profiles and head loss and is usually used where cost is an issue, but a more proactive pressure management is desired, for example where night time pressure is to be reduced for a number of hours to reduce the effects of leakage.
The step before the Time Based Modulation is the so-called Fixed Outlet Modulation which is the most basis control which is achieved by simply modulating the valve to provide a steady outlet pressure (set point) as system flow demands change, and which VAG Plunger Valves can of course handle as well.
Flow or Demand Based Modulation
More water can be saved and more pipe bursts can be avoided when the pressure is following the demand cycle during the whole day, week, month and year.
A flow meter in the main supply pipeline is recognizing the actual demand for water in the network. This value is sent to a computer, where an evaluated curve specifically for this network is stored, this curve is showing the minimum pressure which is necessary to maintain the related flow rate. This method has in the past proven to be the best type of control for areas with changing conditions, head loss, fire flow requirements and the need for proactive control. As demand is reduced primarily at night then pressures are reduced and as demands peak higher pressures can be applied to the district. The effect is an efficient control of pressure and water loss. Additionally as pressures are smoothed out at the weaker extremities of the system the number of new breaks is reduced.
Remote Node Based Modulation
With the Remote Node Based Modulation the pressure will be measured directly in the network at a critical place. The signal is sent via a wireless connection to the pressure reducing unit. This type of control is probably the most proactive and is affected by connecting a remote pressure sensor to the valve controller, by means of radio or GSM.
The remote sensor is usually placed at a critical point in the district and the controller set to change pressure at the valve to always maintain the desired pressure. As with the flow based modulation discussed above this mode of operation also smoothes the system pressure at the weaker extremities and has the added effect of reducing the number of breaks.
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