6
DIRECT NUT OPERATED VALVES: 8” and smaller
valves may be equipped with a top-mounted nut for
direct quarter-turn operation. The nut is 2” square to fit
most valve wrenches and is mounted directly to the
valve plug. To open the valve, slowly rotate the nut 90
degrees in the counter-clockwise (CCW) direction. The
closed position is adjusted with a set screw and lock
nut, see Figure 8. The open position can be adjusted
by moving the bolt along the curved slot.
FIGURE 8. DIRECT NUT ADJUSTMENTS
DIRECT NUT FRICTION ADJUSTMENT: As shown
in Figure 9, valves with direct nut actuators have a
flanged packing follower (18) above the packing (7)
to hold the valve in the open or closed position. If the
valve is difficult to operate or does not maintain its
set position, adjust the clamp bolt (17) to provide
sufficient friction to hold the valve in position. IF the
valve is equipped with a hand lever, the setting
should allow the valve to be operated with about 80
pounds of force on the end of the pipe handle.
FIGURE 9. FRICTION ADJUSTMENT
LEVER OPERATED VALVES: A wrench head and
lever (Figure 10) are available for use over the 2” nut
for direct quarter-turn operation. Various lever lengths
are available for specific direct and reverse pressure
conditions as shown in Table 4.
TABLE 4. APPLICATION OF LEVERS
FIGURE 10. HANDLEVER
The wrench head is placed over the nut and can be
secured with the set screw provided. To open the
valve, rotate the lever 90 degrees in the CCW
direction. The closed position is adjustable with a set
screw and lock nut mounted below the nut, see Figure
8.
GEAR OPERATED VALVES: 4” and larger plug
valves are available with a multi-turn manual gear
actuator. The gear unit has a self-locking worm gear
which multiplies the turning force on the handwheel or
nut so that the valve can be operated with ease. A
clamp-on chainwheel kit can also be used for
installations high above the floor. An indicator on the
top of the actuator housing indicates the position of the
valve plug. The handwheel or nut must be rotated
through 12-80 turns (depending on model) to open or
close the plug valve. The direction of rotation to open
the valve is indicated on the 2” square actuator nut.
WRENCH LENGTH, (Inches)
VALVE DIRECT PRES. REVERSE PRES.
SIZE 100 psi 175 psi 50 psi 175 psi
2 1/2 22 22 22 22
3 22 22 22 22
4 22 22 22 22
6 44 * 44 *
8 44 * 44 *
*Worm gear recommended due to operating torque
CAUTION: Open and close the valve slowly to
prevent water hammer.
(4 Seiten)
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