can be designed to prevent lock gate movement
sonnel from monitoring skew, and ensuring gate
until a specified condition or position is achieved
movements that are uninterrupted.
at the filling or emptying valves.
Controlling closure of miter gates needing a specific
Interlocking gate opening with gage readings on
sequence. The design of some miter gates or their
both sides of a gate. At some locks it is difficult for
seals requires that the gate be closed in sequence,
the operators to observe when the chamber water
e.g., left before right. Current manual procedures
level matches the upper pool stage at the end of a
could be eliminated if gate movements were auto-
filling operation, or when it matches the lower
mated, since the closure sequence could be made
pool stage at the end of an emptying operation.
a part of the program.
They want to have the stages match quite closely
Establishing and remotely resetting limit positions
before opening the gate. For example, it is good
of gates. As with filling and emptying valves, limit
to avoid the opening of miter gates against a
switches would continue to be used as backups
head of water, or to avoid a surge of water past
with automated operation of lock gates, but their
the gate upon opening. With water level moni-
setting or adjustment might be annoying due to
tors installed on each side of the gates, informa-
accessibility problems and fine tuning. Remote
tion could be fed to a program requiring a match
setting of limit switches could be accomplished
of stages before gate opening could be accom-
by relatively simple automated means, facilitating
plished, thus preventing the problems encoun-
the setting of limit switches, and allowing ease in
tered with moderate head differences. This situa-
changing the settings to meet temporary needs
tion is the continuation of the condition stated
imposed by such conditions as worn or damaged
immediately above, but it occurs closer to the
machinery components or foreign material (de-
end of the filling or emptying process.
bris, silt, or ice) interfering with gate operation.
Interlocking gate operation with vessel position in
Programming sector gates to achieve optimum
chamber. Certain designs of lock gates are vulner-
flow-through. The flow between sector gates as
able to damage by vessels such as towboats or
they open is a function of head differential and
barges if they are too close to the gate during
the width of the opening. Since the rate of change
chamber filling or emptying. For example, an
of the width of the opening is dependent on the
accident once occurred in which a vessel in the
speed of the sector gates' movement, program-
chamber was too close to its upper end, and
ming speed variations into the initial stages of
upon chamber filling the vessel hooked the
gate opening could be employed to achieve opti-
underside of the upper gate structure (a tainter
mum flow velocities for the benefit of minimizing
gate) and destroyed it. Another accident
hydraulic forces on waiting vessels and their
occurred when a submerged upper lift gate was
mooring lines.
raised inadvertently while a tow was entering
the chamber. These occurrences could be pre-
General machinery operation
vented by sensors installed in the lock chamber
There are several categories of equipment asso-
and in the upper and lower approaches that de-
ciated with a lock to support the overall opera-
termine whether a vessel or tow is clear of the
tion. These include hydraulic systems, drainage
gate areas before the gate would be allowed to
systems, etc. The operation of these systems and
move. This would be an interlock condition that
equipment can lend itself to automation that will
would have to be satisfied to proceed with pro-
contribute to the best utilization of personnel.
grammed gate operation.
Monitoring and controlling hydraulic systems.
Monitoring and controlling gate skew. Guillotine
Many locks have hydraulic systems for powering
gates, and to a lesser extent tainter gates, are sub-
part or all of the lock machinery. The hydraulic
ject to skew because separate operating machin-
systems may range widely in age and sophistica-
ery is used to move each side of the gate. In some
tion. Most of these systems do not have automat-
cases there are skew indicators that an operator
ed monitoring and control, but automation could
must monitor to keep skew within tolerable lim-
be added to many to make them easier to operate
its, and there are also limit switches that will stop
and more foolproof.
the lifting machinery if skew becomes excessive.
Establishing and operating a machinery alarm sys-
What is suggested here is automated equipment
tem. Most lock machinery is equipped with
that will use skew information as input in order
alarms to indicate malfunction or out-of-range
to feed back adjustments to the lifting equipment
operation. Without automation, an alarm usually
to correct or minimize skew, thereby freeing per-
requires a response from an operator and the op-
7
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