Flowserve Edward Cast Steel Bolted Bonnet Valves - Manual (Page 11)

DISASSEMBLY PROCEDURES FOR
BOLTED BONNET VALVES
INTRODUCTION
Step-by-step disassembly procedures are
described for all types of Edward bolted
bonnet valves, including those with manual
and motor actuators.
It is important that the following para-
graphs be read and understood before
specific disassembly work is started.
FIRST DETERMINE THE AREA
OF FAILURE
Failures or maintenance problems, for
other than check valves, can be divided
into two major areas. The area involved
will affect the disassembly procedure to be
followed. These areas, in general, are:
AREA 1
The impactor Handwheel or Handle, or the
Limitorque Actuator.
AREA 2
The valve internals, including the bonnet,
body, stem, disk, disk-nut, gland and seats.
IF FAILURE IS INDICATED IN AREA 1,
Refer to the applicable section
“Disassembly Procedures for Impactor
Handwheels,” or “Procedures for Removing
Electric Actuators from Valve Bonnets,”
pg. 12.
IF FAILURE IS INDICATED IN AREA 2,
Two methods are available. In Method 1,
the actuator and bonnet assembly may be
removed from the valve body as a unit.
This requires less time but requires ade-
quate clearance area above the valve. The
second method is to first remove the actua-
tor from the bonnet, and then the bonnet
from the body, in separate steps.
For Method 1, leave the valve actuator
mounted on the bonnet and follow instruc-
tions for “Disassembly Procedures for Valve
Parts,” pg. 14.
For Method 2, first remove the operator by
following the applicable section,
“Disassembly Procedures for Impactor
Handwheels” or “Procedures for Removing
Electric Actuators from Valve Bonnets”
pg. 12. Then proceed to the section,
“Disassembly Procedures for Valve Parts,”
pg. 14.
If failures are indicated in any combination
of Areas 1 & 2, then each of the respec-
tive procedures must be followed . For
check valves without stems or actuators,
simply use the proper section under
“Disassembly Procedures for Valve Parts, “
pg. 14.
DISASSEMBLY PROCEDURES FOR
IMPACTOR HANDWHEELS AREA1
Edward valves use several designs of
Impactor handles or handwheels, depend-
ing upon the valve size and pressure class.
Handwheels can be removed while the
valve is pressurized. If under pressure, the
valve should either be fully closed or back-
seated in the full open position.
IMPACTOR HANDLES AND
HANDWHEELS
Not illustrated, but of similar construction
to Illustration No. 4, pg. 12, are Impactor
handles. The following instructions apply,
in general, to all.
1. Remove the handwheel lock nut, which
is the uppermost part on the top of the
valve stem. On some designs, it is a fric-
tion device and is merely unscrewed.
On others, a roll pin must first be driven
out. On another design, a small lock
screw must be unscrewed.
2. Mark the relative position of the hand-
wheel and crossarm so the original
relationship can be restored when
reassembling. If this is not done, the
handwheel could be reassembled 180°
out of the original position.
As a general reminder, make sure all pres-
sure is removed from valves, both upstream
and downstream, before any disassembly
work is started. An exception to this is valves
requiring service only on the actuator (Area
1) where the valve can remain in service.
1. For service in Area 1.
a. If pressure is to be maintained in the
valve, fully close the valve or backseat
in full open position. On electric oper-
ated valves with non-revolving stems,
the valve must be backseated in the
full open position only.
b. If no pressure is to be maintained in
the valve, close the valve fully and
open approximately 1/8".
2. For service in Area 2.
Close the valve fully and open approximate-
ly 1/8". Service Area 2 only without pres-
sure in the valve.
CAUTION
11
Flow Control Division
Edward Valves
Disassembly Procedures