APV
The APV (Advanced Pilot Value)
The APV (Advanced Pilot Valve) has been developed by i2O to replace the conventional pilot valve normally fitted to the PRV.
With a conventional pilot, P2 is set by adjusting the spring tension inside the pilot valve. It is designed for occasional, manual adjustment and is therefore not suitable for the continuous adjustment needed in an Advanced Pressure Management system. The APV has been designed to make smooth, continuous adjustments to P2 as demanded by the i2O controller. When the controller asks for a value of P2, the APV adjusts the PRV with no overshoot until the new value has been achieved. Once the new value has been reached, the APV can maintain it automatically under varying flow or P1 conditions (assuming P1 is adequate) until the controller requests a new value of P2.
Key Features
Compatibility - The APV is compatible with all globe type PRVs.
Low power consumption - The APV consumes a tiny amount of battery power with each adjustment. Battery life depends on a number of parameters which are calculated for each DMA. A typical battery life would be five years based on an average of 96 adjustments per day (1).
Accurate pressure control - It is important that the PRV can accurately maintain the level of P2 that has been requested by the controller under varying flow rates and values of P1 (assuming P1 is sufficient). This depends on the whole PRV pilot valve system. However, tests show that a PRV with an APV installed can achieve similar or better pressure control than a PRV with its original pilot valve installed. On a typical PRV this would be +/- 0,5m.
Smooth adjustment - It is crucial not to create pressure spikes which may damage the network and defeat one of the key objectives of pressure management, which is to extend asset life. Pressure is adjusted slowly and smoothly by the APV and reaches the requested level with no overshoot. As DMAs can vary in their response to pressure changes, there is also a facility to adjust the rate of change of pressure to the optimum value during system set up.
Large pressure range - The standard range of adjustment of P2 is 30m. The upper value of the range for the standard APV is set on installation, up to a maximum value of 78m or 154m depending on spring selection. Specially configured APVs can also be supplied with a maximum pressure rating of 255m (PN25)
Auto-bleed - Air in any pilot valve circuit will seriously impair PRV performance. The automatic bleed system on the APV overcomes this potential problem without the need for manual purging of the air.
Robust and water-proof - The environment in which the APVs are installed is very demanding with high levels of moisture, temperature variation, vibration and flooding. The APV has therefore been designed to be extremely robust with an IP68 watertight enclosure.
(1) The controller and APV share batteries. Five year battery life is also based on daily GPRS communication.