Flowserve V-377 R4 Edward Valves - Manual (Page 22)

22
Flow Control Division
Edward Valves
Edward pressure-seal valves use various
types of Limitorque operators, depending
upon the size and pressure class, which
determines the torque requirements,
whether the stem is revolving or non-revolv-
ing, and whether the valve takes the stem
thrust (torque-only unit) or the operator
takes the stem thrust (torque and thrust
unit). The procedures below describe the
removal of these various types from the
valve yoke. Also included are complete
instructions for resetting the torque and
limit switches. Disassembly procedures for
the Limitorque operators themselves are not
included and appropriate instructions
should be obtained before starting. On torque-only Limitorques, the operator
can be removed while the valve is pressur-
ized, but caution must be observed to
make certain that the valve is first in the
back-seated or fully open position. See
“Caution” on page 18.
All of the following disassembly procedures
are arranged in accordance with the
general comments on page 18. Study these
pages carefully before beginning.
First, determine whether the valve stem is
revolving or non-revolving. For non-revolv-
ing stem valves, several procedures are
shown, depending upon the operator type.
Then determine whether the operator is a
torque-only or torque and thrust unit. Revolving Stem Valves or Non-
Revolving Stem Valves with Torque-
only Units
All revolving stem valves use torque-only
units. The operator drive nut is connected
to the stem through a key. See Illustration
No. 14. Non-revolving stem valves using
torque-only units, have their drive nut
splined to the valve yoke bushing. See
Illustration No. 15.
1. Disconnect the electrical wiring to the
operator.
2. Position a sling on the motor operator
and attach a chain hoist of suitable
capacity to the sling.
3. Remove the nuts from the underside
of the yoke flange.
Procedures for Removing Limitorque Operators from Valve Yokes
Illustration No. 14
Torque-Only Limitorque Operator on
Revolving Stem Valve (SMA or SMB)
Illustration No. 15
Torque-Only Limitorque Operator on
Revolving Stem Valve (SMB-4T or 5T)
Illustration No. 16
Torque-Only Limitorque Operator on
Non-Revolving Stem Valve