Flowserve V-378 R1 Edward Equiwedge Gate Valve - Manual (Page 13)

13
Flow Control Division
Edward Valves
Disassembly Procedure for Equiwedge Gate Valves
Introduction
Step-by-step disassembly procedures are
described below for all types of
Equiwedge pressure seal gate valves,
including those with manual and motor
actuators. It is important that the
following instructions be read and under-
stood before any specific disassembly
work is attempted.
First determine the problem area.
Maintenance problems can be divided into
three major areas, and the area involved
will affect the disassembly procedure.
These areas,in general, are:
Area 1 The handwheel, or a manual or
electric motor actuator.
Area 2 The yoke assembly including the
yoke, yoke bushing, and bearings.
Area 3 The valve internals including the
bonnet, body, pressure seal gas-
ket, stem, gate, and seats.
If the problem is in Area 1, usually a man-
ual or electric actuator will be involved
and not a handwheel; see Appendix A,
pg. 29.
If the problem is in Area 2, it will be
necessary to remove the valve actuator
only if the valve is handwheel actuated or
has a torque-only manual or electric
actuator. See procedure on pgs. 28 and
29 and select the proper one.
If the problem is in Area 3, two methods
are available. In method 1 the yoke and
actuator assembly may be removed from
the valve body as a unit. This saves time,
but requires adequate clearance. In
method 2 the actuator and yoke are
removed separately.
If problems are suspected to exist in any
combination of Area 1, 2 or 3, then each
of the respective procedures must be
followed.
CAUTION
AS A GENERAL REMINDER, MAKE SURE ALL THE PRESSURE IS RELIEVED, BOTH UPSTREAM AND DOWNSTREAM AND IN THE
CENTER CAVITY, BEFORE DISASSEMBLY WORK IS STARTED. Exceptions to this rule are noted below.
1. For service In Area 1
If pressure is to be maintained in the valve, backseat to full open position. The actuator, both manual or electrical, torque-only and
torque and thrust types, may be removed. The blowout force on the stem due to pressure in the line will keep the stem on the backseat.
2. For service in Area 2
If pressure is to be maintained in the valve, the yoke may be removed on Types III, IV, and V. The blowout force on the stem due
to pressure in the line will keep the stem on the backseat. UNDER NO CIRCUMSTANCES SHOULD THE YOKE BE REMOVED ON
TYPES I AND II WHILE UNDER PRESSURE.
3. For service In Area 3
Close the valve fully and then open 1/8” (3mm). SERVICE AREA 3 WITHOUT PRESSURE IN LINE.