Page 342 - Water Loss Control

Contr olling Real Losses—Pr essur e Management 311

FIGURE 18.7 Pressure-reducing valves working in parallel.

18.3.4 ACVs—Fixed Outlet
ACVs are a traditional method of control and use a basic hydraulically operated control
valve. See Figs. 18.7 and 18.8. Later in the book we will be discussing controllers and
varying profiles. The fixed outlet control valve method is effective for areas with low
head losses, demands, which do not vary greatly due to seasonal changes and areas
with uniform supply characteristics.

Fixed Outlet Hydraulic Control
Clockwise
rotation
C
Pilot valve
opens A
Open

B

Flow
A

When the pilot valve B is open, the pressure in the control circuit does not exert any
force on the membrane of the main valve A, therefore the main valve will open.
FIGURE 18.8 Pressure-reducing valve diagram.