Instruction Manual - Rodney Hunt Company

Sluice Gate Trouble Shooting Tips (cont’d.)
SYMPTOM CAUSE REMEDY
Chatter.
Chatter.
Slow rhythmic
bang during
closing.
GATE WILL NOT
OPEN
STEM TURNS ON
RISING STEM
GATE
26
May occur when closing hydraulically
operated gates. The speed
control valve may be adjusted for
a speed high enough to decrease
pressure to the top of the cylinder
to a level where the pilot operated
check valves may close, stopping
the gate until pressure builds up.
Also may be heard on electric hoists
with dry stems or grit laden grease
on stems.
Generally occurs on electric hoist
operated gates which during their
closing stroke have the condition
that the resistance to closing offered
by water pressure and sliding
friction is nearly equal to the dead
weight of the disc. The disc then
remains stationary while the thrust
nut travels downward until it uses
up the vertical clearance within the
pocket at which time the disc will
drop with a small bang to hang on
the thrust nut. This repeats until the
water pressure and friction is sufficient
to need constant nut force to
move.
Locking plates still in place. See
Page 4.
Key not installed in stem coupling or
thrust nut, allowing stem to thread
itself out.
Decrease gate closing speed.
Clean and lubricate stems.
If the noise is unacceptable shims
may be secured in thrust nut
pocket to nearly eliminate vertical
clearance.
Remove locking plates.
Thread stem back into coupling or
thrust nut and install key and set
screw.