Valves with absolute shut-off capabilities in high pressure and high temperature steam are
required in a number of areas in a fossil fueled power plant. Copeland ball valves are so
successful because they supply long term cost savings by eliminating steam leaks to the
atmosphere or downstream.
In many areas where traditional globe valves have been used, Copeland Power Valves have
lasted longer and performed more reliably. A harder sealing surface, a forged body to prevent
the possibility of body leaks and a unique, live loaded packing assembly are a few of the
primary reasons for the Power Valve's tremendous acceptance.
Typical Applications
Applications for severe service ball valves in power plants typically involve high-pressure steam,
ash slurries or corrosive liquids. Key areas where these valves are most often used include the
following:
Turbine
The turbine and main steam drains need high pressure; small bore valves during start-up and
shutdown of the unit to drain away condensation. The valves are open until the turbine is
brought on-line and closed until the next shutdown. Similar applications are found around the
feed water heater, the economizers and in by-pass lines of larger valves. The turbine seal
steam supply system also utilizes them for isolation of the turbine bearing glands.
Condensate Drain Valves Above and Below Turbine Throttle Valves
Turbine Intercept Before and Seat Drain
Steam Drum Vents and Drains
Steam Supply to Vacuum (Air Ejector)
Steam Trap Bypass and Isolation
Attemperator
Steam Sampling
Isolation
Feedwater Heater Isolation
Typical operating conditions of feed water heater isolation valves are 350 - 400°F and 3500 psi
for a sub-critical plant and 4500 psi for a super-critical station. Reliable isolation is important to
prevent feed water from leaking and overloading the heater drain system. Maintenance
personnel must be able to plug, replace or rod out the tubes without shutting down the whole
unit or as much as 33% of the plant's thermal efficiency can be lost. Reducing the time it takes
to repair the heaters by just a few hours can result in savings that quickly pay for the initial cost
of the valve.
The valves remain in the open position most of the time but must close tightly when the heater
is brought off-line for maintenance. Rust, scale build-up or thermal expansion are often issues
that can cause rising stem or valves with soft sealing surfaces to fail. An extra hard sealing
surface and an over sized stem and actuator are important to insure that the valve will operate
properly and reliably.
Steam Sampling
Isolation
Boiler Feed Pump and Heater Systems
Boiler circulating pumps are often found in plants larger than 350 mw to circulate water through
the boiler. During start-up, fill valves are used to pressurize the pump and associated piping.
Once the pump is brought on-line, the fill valves are closed. The same types of valves are used
to vent or drain pumps during routine maintenance.
Warming, Drain and Recirculation
Blow down & Vents
Pump Recirculation
Bypass & Isolation Valves
Heater Gauge Glass Isolation and Drain Valves
Sample Stop Valve
Heater Drain
High Level Dump
High Pressure Feed Pump Bypass Valve
Feed Pump Discharge Return to De-Aerator
De-Aerator Drain
Condensor Drain
Economizer
Economizer Drain
Economizer Sampling & Vent Valves
Economizer Inlet Pressure Connection (Root) Valve
Superheater
Header Inlet Leader Drain (Primary)
Bypass Systems
Drain and Vents
Power Operated Safety Relief Valve
Sampling Isolation Valve
Steam Drum and Boiler
Steam drum vents require valves for venting the steam drain and isolating boiler drum or steam
drum controls such as the water column and level alarms. They are also used to remove boiler
sludge or water deposits during start-ups and shutdowns. Other applications include mud
drum drains, continuous blow-down, fly-ash/gas vents, spray water and soot blowers
Mud Drum Drains Drains
Continuous Blow-Down
Fly-Ash & Gas Vents
Loop Vent
Main Steam Start-Up
Mixing Header Pressure Connection Valve
Spray Water and Steam Supply Isolation
