FUNCTION

 

Controllers enable the outlet pressure of a Pressure Reducing Valve

(PRV) to vary against set criteria. The most basic of controllers

provide a simple two-stage, time-activated control. This enables

night time pressures to be reduced within a zone. The next level

of controllers enables multiple outlet pressures to be set following

a changing profile  throughout a day. More advanced controllers

utilise flow modulation to set the PRV pressure based on the flow

recorded on a nearby meter. This protects against frictional head loss, which is higher at faster flows. Advanced Pressure Optimisation solutions will calculate the optimal pressure to be delivered in a zone based on head-losses and flow rates and will update this model over time.

 

Other forms of control operate on a ‘closed loop’ system by linking the PRV pressure to the logged Critical Pressure Point (CPP), which may be at a location far from the PRV. When the pressure at the CP reduces, the controller will receive a signal indicating that pressure needs to increase. The controller will then increase the delivery pressure of the PRV. 

 

 

BENEFITS

 

There are many benefits to controlling pressures. Areas of operational and customer benefit include:

 

• Water leakage reduction

• Water burst frequency reduction

• Energy savings

• Lower operating costs

• Improved levels of customer service

• Extend asset lifetimes

 

 

 

SYSTEM REQUIREMENTS

 

To assess the suitability of pressure management in a particular system, utilities should first: 

 

• Identify potential zones, installation points, and customer issues

• Cacluate the minimum acceptable pressure within the network

• Gather field measurements on current flow and pressures

• Estimate potential benefit through calculation of likely pressure reduction

• Select the most appropriate level of control for the zone