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KEYSTONE FIGURE 221/222 BUTTERFLY VALVES
INSTALLATION AND MAINTENANCE INSTRUCTIONS
INSTALLATION IN A NEW SYSTEM
It is common practice to use the valve to help
in alignment of the flanges prior to welding the
flanges into the pipeline. In such cases, the
following instruction applies:
1. Align both mating flanges with the valve
center line and secure in position using the
flange bolts.
2. Position the flange/valve/flange assembly in
the pipeline.
3. Tack weld the flanges to the pipeline.
4. Remove the flange bolts and the valve.
5. Finish weld the flanges to the pipeline and
allow to cool fully.
6. Follow the procedure for installation in an
existing system.
WARNING
Do not finish weld the flanges to the pipeline with
the valve still assembled to the flanges as this will
result in serious damage to the valve seat.
NEW SYSTEM
1. Center a flange-valve-flange assembly
between the pipes.
2. Tack weld the flanges to the pipes.
3. Remove the valve and finish weld.
Install the valve according to the procedure
in the left column.
3
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