6
KTM
OM-2 GRATITE
®
SEAT BALL VALVES
INSTALLATION AND OPERATION MANUAL
FIGURE 9
Body sealing structures
Body 1
Stud 1
Gasket
CAUTION
The sealing portion between body and body cap
is provided with a graphite gasket as shown in
Figure 9. In case of slight leakage, the fastening
bolts should be moderately tightened.
10 TROUBLESHOOTING
Trouble examples
Causes
Measures
Unsmooth operation
1. Jamming due to solids or slurry in the fluid.
1. Clean the inside of the valve. If neccesary, replace parts (ball,
seats, stem bearing, thrust bearing).
2. Ball is corroded by fluid.
2. Replace with ball made off corrosion resistant material.
3. Fluid sticks to ball and seats.
3. Clean the inside of the valve. If neccesary, replace ball or seats, or
replace with ball valve equipped with metal seats.
4. Unusual pressure rise exceeding seat rating limit when shutting
the valve.
4. Take measures to prevent abnormal pressure rise in pipe and
replace seat.
Outside leakage
1. Sealing performance of gasket and gland packing decreases
gradually when operation frequency is high or the high
temperature fluid flows
1. The fastening nuts or bolts at gasket and gland packing are
required to be lightly tightenend, or gasket and gland packing
replaced.
2. Sealing performance of gasket and gland packing decreases by
abnormal pressure rise in the cavity.
2. Replace by ball equipped with small purge hole for releasing
abnormal pressure rise.
3. Sealing performance of gasket and gland packing decreases when
shutting the valve during abnormal pressure rise in the piping.
3. Take measures to prevent pressure rise and replace seats,
gaskets and gland packing.
Seat leakage
1. Ball and seats are damaged by solids and slurry in the fluid.
Fluid sticks to ball and seats.
1. Clean the inside of the valve. If necessary, replace ball or seats, or
replace with ball valve equipped with metal seats.
2. Ball is corroded by fluid.
2. Replace with ball made of corrosion resistant material.
3. Seat and cushion deformation due to abnormal pressure rise in
the cavity.
3. Replace by ball equipped with small purge hole to release
abnormal pressure rise.
4. Unusual pressure rise exceeding seat rating limit is when shutting
the valve leads to seat deformation.
4. Take measures to prevent abnormal pressure rise and replace
seats.
Nut
11 VALVE DISASSEMBLY
Assemble/disassemble the valves in a clean,
well-lit and well ventilated place.
WARNING
Before removing the valve from the piping, ensure
that the system has been fully depressurized
and any dangerous fluids have been drained off.
Failure to do so may cause serious personal
injury and/or damage to the valve. Maintenance
of the valves must be performed only by qualified
personnel. Never operate/disassemble the valves
before checking the safety. The valve is extremely
heavy; ensure a stable position to prevent it from
falling down when assembling/disassembling.
There is a cavity inside the ball valve when
the ball is fully open or fully closed. For a safe
disassembly, following instructions must be
carried out.
1. Half open the valve when still installed in
piping, and make no pressure remains in the
cavity. Failure to do so may result in injury,
explosion or fire caused by the remaining
pressure.
2. Before disassembling the valve, make sure
that it has been decontaminated of any
harmful gasses or fluids, and disassembly is
done at a well ventilated place and within a
safe temperature range for maintenance.
3. Pressure of flammable gas and other
dangerous fluids must be checked only at well
ventilated places outdoors, far away from any
fire source.