Brochure
The high pressure (HP) and intermediate pressure
(IP) drum level control application is fairly moderate
during typical plant operation. However, during
startup the pressure drop across the valves,
particularly the HP drum level control valve, can
produce damaging cavitation.
Fisher HP and IP drum level control valves are
designed to eliminate cavitation during startup
while providing the rangeability required for smooth
transition to normal operation.
HP/IP Drum Level Control Valve
In the normal range of plant operation, the boiler
feedwater regulator experiences high ow rates with
low differential pressure. However, during startup,
this valve experiences low ow rates with very
high differential pressure, which can cause severe
cavitation damage. Some feedwater systems are
designed using one valve to handle startup
and normal operating conditions. Others are
designed using a separate small startup valve to
handle low ow, cavitating conditions and a second
larger valve to handle high ow rates required for
normal operation.
Fisher feedwater startup and regulator valves are
engineered to eliminate cavitation during initial
operation and provide the rangeability required
for smooth transition from startup through full
load operation.
The Feedwater System
Boiler Feedwater Startup and Regulator Valve
8 | Fisher
®
Power Solutions
PRODUCT FEATURES
nAdvanced sealing technology provides tight shutoff and extends service life.
n High turndown handles extreme flow rates.
n Characterized cage provides low-ow cavitation protection during initial operation and necessary
ow as pressure rises.
nOptional trim allows passing of 19 mm (.75 inch) particulate.
n One valve solution: offers anti-cavitation protection during low flow, high pressure drop
startup, and unrestricted high flow during low pressure drop, full load conditions.
n Two valve solution: offers a dedicated startup valve to handle cavitating conditions in parallel with
a larger standard trim valve, handling full load conditions.
n Pneumatic piston actuator provides highly accurate step positioning and stable valve response.