Valves
DOE-HDBK-1018/2-93
VALVE ACTUATORS
Hammer Handwheel
Figure 31 Hammer Handwheel
As illustrated in Figure 31, the
hammer handwheel moves freely
through a portion of its turn and
then hits against a lug on a
secondary wheel. The secondary
wheel is attached to the valve
stem. With this arrangement, the
valve can be pounded shut for
tight closure or pounded open if it
is stuck shut.
Gears
Figure 32 Manual Gear Head
If additional mechanical advantage is
necessary for a manually-operated
valve, the valve bonnet is fitted with
manually-operated gear heads as
illustrated in Figure 32. A special
wrench or handwheel attached to the
pinion shaft permits one individual to
operate
the
valve
when
two
individuals might be needed without
the gear advantage. Because several
turns of the pinion are necessary to
produce one turn of the valve stem,
the operating time of large valves is
exceptionally long.
The use of
portable air motors connected to the
pinion shaft decreases the valve
operating time.
Rev. 0
ME-04
Page 45
