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YarwaY water column
InstallatIon, operatIon and maIntenance InstructIons
1 dESCrIptION
Yarway water columns are designed and
manufactured in accordance with aSme Boiler
& Pressure Vessel code. they are used for
gage support and to reduce transient level
fluctuations, and when probes are installed,
they are used as part of an electronic level
indicating system.
2 prINCIpLE OF OpEratION
2.1 packing
Prior to installing this equipment clean all
packing material from around the unit and
inspect for any damage that may have occurred
during shipment. any claims for loss or damage
must be filed by the purchaser with the carrier.
a copy of the bill of lading and freight bill will be
supplied on request by emerson - Harlingen.
2.2 water column (see figure 1)
warNINg
The nature of the electronics, the harsh operating
environment and the potential hazards associated
with live steam require that only qualified
personnel install and maintain this equipment.
Without adequate qualifications, an operator
could allow live steam to escape which may cause
property damage or severe personal injury.
For safety reasons, it is important to take the
following precautions before starting work on
the remote level indicator:
1. the lines that the water column is to be
installed to must be depressurized, drained
and vented before installing the water
column.
2. Handling and installation of the remote level
indicator must be carried out by personnel
trained in all aspects of installation and
manual/mechanical handling techniques.
3. welding must be performed only by
personnel qualified and certified to all
applicable national and local codes.
4. Before making any electrical connections,
ensure that the power source to be used
is isolated by use of the appropriate circuit
breakers and/or switches.
all wiring must be in accordance with
applicable national and local codes by qualified
personnel only.
the water column is fixed to the steam drum
either by being welded directly to the isolating
valves or welded to flanges that mate with
existing flanges on the steam drum tapping
points. a steam inlet line must be installed
to provide a free flow of steam to the water
column. the steam line must be level or slope
downward as shown in figure 1. when globe
valves are used as the isolation valves, they
must be installed with the stem horizontal.
Steam connection piping shall be
level or slope downward
Steam drum
Drum tapping
centers
water connection piping shall be at same elevation as
drum nozzle or slope upward
FIGure 1
water column Installation
Ideally, the return water leg should be
horizontal. this leg may, however, be sloped
down to the drum, in which case it must be
insulated. In no case should the steam line or
water column be insulated. Insulating these
inhibits condensation, which is essential for
proper circulation through the water column.
water columns with three maximum pressure
ratings are available - 850 psig (58 barg),
1800 psig (124 barg) and 3000 psig (206.9 barg)
design. the fittings on steam generators of
lower pressure usually have a lesser rating.
as a result, the overall rating of a system is
governed by the lowest rating of any of the
components.
column centers
optional column mounted
probe junction box
2
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