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Electrode Boiler
Fe e d w a t e r a n d w a t e r l e v e l
controller
Feedwater is piped into the boiler
near the base of the pressure
vessel. The feedwater regulating
valve, check valve, and gate valve
are normally furnished with the
boiler.
A bypass (requiring three valves)
may be installed around the feed
water regulating valve to facilitate
valve replacement.
The water level transmitter
mounted on the water column is a modulating 4-20 mA type. In order to maintain a consistent water
level in the system, the transmitter signal opens the feedwater valve when the boiler drops below the
acceptable operating level and closes it again when water level rises. Feedwater may also be added
manually through the customer bypass.
Pressure controls
A boiler pressure gauge, pressure transmitter, and high pressure limit
control are piped to a manifold with unions for each branch. The
manifold is piped to a coupling in the steam space of the boiler (above
the waterline). The piping schematic shows actual configuration for
each boiler.
A system pressure gauge and transmitter are installed downstream of
the steam outlet back-pressure valve. Their function is to give a
comparative reading between vessel pressure and pressure in the pipes
downstream of the boiler steam valves.
Pressure vessel blowdown
Connect the blowdown valves as shown on the piping schematic.
Usually there will be two valves in series. For pressure vessel blowdown
procedures see Section 9-2, Daily Maintenance.
The discharge from the blowdown piping is extremely hot and must be piped
to a safe point of discharge.
A blowdown tank (optional) may be used as a means of safe disposal of blowdown discharge. The
blowdown pipe between the valves and blowdown tank should provide for connection of additional hot
water from the surface blowdown line, water column drain, etc.
6
Figure 4 - Feedwater piping w/3-valve bypass
Caution
!
Regulating Valve
Strainer
Check Valve
Gate
valve
To boiler
steam space
To main steam
piping
Figure 5 - Pressure controls
750-272
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