SICCA
ATTENTION
10
6.2 Installation position
The valve bodies are marked with an arrow indicating the flow
direction. Valves should always be installed in such a way that
the actual flow direction of the medium matches the arrow on
the body.
6.2.1 Gate valves
In general flow may pass a gate valve in either direction.
However in high pressure valves with pressure relieving
arrangement (refer clause 6.6, Execution ref. PR-01 to
PR-06) valves are unidirectional. When installing a gate valve in
a horizontal pipe, the stem should be vertical, i.e. the handwheel
or actuator is on top. Inclined or horizontal stem position (e.g.
in a vertical pipe) is also possible, in this case, however, the
actuator must be supported by some suitable means.
6.2.2 Globe valves
Flow may pass a globe valve in either direction if not indicated
otherwise. When installing a globe valve in a horizontal stem
position (e.g. in a vertical pipe) is also possible, in this case,
however, the actuator must be supported by some suitable
means.
Forged Steel Globe Valves in High Pressure /
Temperature Drain Service
In Start-up Vent / Drain application, the Globe valves are likely
to accumulate foreign particles like scale or rust. During ‘‘rush’’
of the flow, these particles may erode Sealing Surfaces on Disc
and Body Seat, when the flow is ‘‘Below the Disc’’.
KSB’s ‘‘Y’’ type Globe Valves can be installed individually or in
tandem for improved life time of valves in the high differential
drain service with good shutoff function, with ‘‘Flow over the
Disc’’ orientation.
In such start-up / vent and drain applications, we recommended
‘‘Flow over the Disc’’ for following reasons :
- minimal Seat erosion due to occasionally flowing sediment /
foreign particles
- using the differential pressure, acting on top side of the Disc,
to assist effective sealing
- minimizing loads / stress in the Stem
This orientation of the valve i.e. ‘‘Flow over the Disc’’ will serve
these purpose and the life cycle time of Globe Valves may be
extended.
6.2.3 Check valves
Swing check valves should preferably be installed in horizontal
pipes. When installing them in vertical pipes, make sure that the
flow direction is upward, so that in the unpressurized condition,
the disc will be closed by its own weight.
Check valves are provided with two extra long studs (902) or
a tapped hole in the cover (refer sketch SCC 150-600) which
serves a means of lifting lugs.
6.3
Pressure seal design (gate and swing check
valves)
On gate valves with pressure seal bonnet (166)
of fig. GTC 900-2500 & Pr. seal bonnet (139) of
fig. GTC 3100-3600 where the medium trapped in the closed
valve can heat up, the user must check whether a connection
from the middle of the body to the upstream side of the gate
ATTENTION
valve (flow in only one direction) or a body safety device (flow
in either direction) should be provided.
If a swing check valve and a gate valve with pressure seal
bonnet (166) are connected in series over a short distance
then the medium trapped when the valve is closed can cause
a pressure rise at the pressure seal bonnet and the closing
element. The user must fit a body safety device/valve on the
pipe line to protect the Check valve body from being over
pressurized due to entrapped fluid between closed elements
of Gate & Check valve. If there is any doubt do not hesitate to
contact KSB.
6.4 Welding instructions / installation of pipe
Responsibility for welding the pipes lies with the piping
installation contractor.
When welding valves on to the piping or when
welding pipes after the valves have been
installed, the welder must make sure that no
foreign particles, e.g. weld beads, enter the valve body and
remain there, because these will cause damage to the valve
seats and or the valve stem.
When welding the valve into the pipeline, take
special precautions, i.e. welding in several
steps, to that the temperature in the middle of
the body does not exceed the maximum permissible operating
temperature. During the welding process, Gate / Globe valves
must be kept in open position. Follow the guidelines from
applicable codes for welding procedure / post weld procedures.
Do not attach the welding cables (opposite
pole) to the moveable parts of the valve,
otherwise these parts may be scorched.
6.5 Actuated valves
Electrical cables may only be connected by qualified
personnel.
The applicable electrical regulations (e.g. VDE),
also for equipment in hazardous locations, must be
observed.
All electrical equipment such as actuator, switchboard, magnetic
valve drive, limit switch etc. must be installed in floodproof dry
locations.
Voltage and frequency must match the valves stated on the
name plate.
6.6 Body safety arrangement (pressure relief)
Heat buildup of trapped liquid volumes is a
phenomenon which mainly affects gate valves.
If there are liquid residue in the valve body after the hydrostatic
pressure test, for instance, or condensate has collected in the
valve body due to a particular operating condition, there is a
risk of an impermissible pressure rise when the body is heated
up by hot water or steam in one or both of the adjoining pipes.
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Summary of Contents for SICCA GLS Series
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