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KEYSTONE Figure 990/991 ButterFly valves
InstallatIon, operatIon and maIntenance InstructIons
3 FlaNgE aNd pIpElINE cOmpaTIbIlITY
Figure 990/991 valves are suitable for use with
flanges according to PN 10, PN 16, aNsi 150
and Bs table e. Figure 990/991 is a wafer type
valve and is intended to be clamped between
flanges attached to the pipeline.
the minimum allowable pipeline bore at the
flanges shall be the 'Q' dimension shown in the
valve data sheet plus adequate allowance to
ensure the disc edge does not interfere with the
pipeline bore.
D max.: the optimum inside diameter (iD) is
equal to the inside diameter of flange
standard eN 1092-1, table 8, type 11.
For larger than D max inside diameters
or other flange types please contact
your local emerson sales organization,
as larger inside diameters might result
in reduced valve functionality.
For flanges with a raised face the diameter of
the raised face shall be a minimum of 10 mm
larger than the 'yy' dimension shown in the
data sheet.
Do not use flange gaskets, these lead to valve
damage!
4 INSTallaTION
Installation in pipeline
Figure 990/991 valves are bi-directional and
there is no need to identify upstream and down
stream orientation.
Figure 990/991 valves can be installed in
vertical or horizontal pipelines and any
intermediate orientation.
there is no restriction on the valve stem
position (vertical, horizontal or oblique),
although for slurry service and media, which
have a tendency to deposit sediment, the
recommended installation position is with
the stem horizontal and the lower disc edge
opening downstream.
Installation in an existing system
(see diagrams)
1. Check that the gap between the flanges
can accommodate the valve face to face
dimension.
2. spread the flanges using suitable tooling
such as flange spreaders to enable ease of
insertion of the valve between the flanges.
WarNINg
Do not use the valve as a lever for this purpose.
3. Open the valve until the disc is free of the
seat but still contained within the face to
face of the valve.
4. loosely insert two or more flange bolts
through the holes in the lower part of the
flanges to help support the valve.
5. Carefully slide the valve between the
flanges, center the valve body with the
pipeline axis, and insert the remaining
flange bolts.
6. Open the valve fully, checking that the disc
edge does not interfere with the pipeline
bore.
7. remove any flange spreaders that have
been used and at the same time tighten
the flange bolts 'hand tight'. ensure that
the valve remains centered to the pipeline
axis by slowly closing the valve (clockwise
rotation of the disc stem) to check that
adequate clearance has been maintained
between the disc edge and the pipeline bore.
8. re-open the valve (counter clockwise
rotation of the disc stem) and tighten all
flange bolts to the recommended torque
of the bolt supplier using the diagonal
sequence method.
9. Operate the valve to the desired position.
Q
yy
Open
Flow
2
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