Flowserve Edward Cast Steel Bolted Bonnet Valves - Manual (Page 15)

15
Flow Control Division
Edward Valves
Reassembly Procedures
4. The bonnet end opening should be kept
covered when ever possible.
REASSEMBLY PROCEDURE FOR
BOLTED BONNET VALVES
INTRODUCTION
The reassembly procedures in this manual
are not as detailed as the disassembly
instructions since, in many cases, just a
reverse procedure is used. However, step-
by-step instructions are provided. In addi-
tion, the following general points should
be considered.
1. The most important consideration in the
reassembly of valves is cleanliness. All
loose scale should be removed with a
wire brush, emery cloth, or acid solvent.
Oil and grease should be removed from
all parts with a suitable solvent to pre-
vent any foreign matter from collecting
on sealing seating surfaces.
2. Unless it is impossible to do so, use a
new gasket when reassembling a
bonnet which has been disassembled
whether it was leaking or not.
3. When reassembling valve bonnets,
always examine stem packing and
replace if necessary.
4. Observe all of the reference marks or
prick punch marks assigned during
disassembly so that the original part
relationships can be maintained.
STOP AND STOP-CHECK
(NON-RETURN VALVES)
See Illustration No. 1, pg. 5.
1. Insert the disk, disk-nut, stem assembly,
or the disk-piston and stem, lowering
carefully until they rest on the valve seat.
Hold the stem centrally in the valve
bore.
2. Install a new gasket on the body.
3. Lower the bonnet into position, rotating
the stem as necessary to engage the
yoke bushing threads.
4. Install and tighten the bonnet stud nuts
of cap screws in accordance with the
torque values shown on pg. 4. All nuts
or cap screws must be tightened uni-
formly in a star pattern to avoid cocking
the bonnet.
5. Reassemble the actuator to the valve
using a procedure opposite the disas-
sembly.
PISTON LIFT CHECK VALVES
See Illustration No. 7, pg. 14.
1. Insert the disk-piston, lowering it careful-
ly until it rests on the valve seat.
2. Install a new gasket on the body.
3. Lower the cover carefully onto the valve.
4. Install and tighten the cover stud nuts or
cap screws in accordance with the
torque values shown on pg. 4. All nuts
or cap screws should be tightened uni-
formly in a star pattern to avoid cocking
the cover.
SUPPLEMENTARY REPAIR
INFORMATION
In analyzing valve trouble in the field, it is
important to consider the following factors:
1. Size of the valve.
2. Figure number of the valve.
3. Lot number of the valve.
4. Service (water, oil, gas, super-heated
steam, etc.).
5. Operating pressure and temperature.
6. Direction of flow through stop valves
(inlet pressure above the disk or below
the disk)
7. Rate of flow through the valve (lbs. per
hour or gallons per minute).
8. At what pressure, temperature of flow
rate does the reported trouble occur.
9. Pressure drop across the valve.
INFORMATION REQUEST
If the maintenance problem looks particu-
larly difficult, it is suggested that you con-
tact your local Edward Valves representa-
tive. He is familiar with these maintenance
instructions and has a variety of engineer-
ing data sheets. In all communications with
your local representative concerning diffi-
culties, mention the valve size, figure num-
ber, lot number (if one is given) and as
many of the nine conditions listed above
as possible. Some of this information is
found on the nameplate attached to the
valve bonnet.