fects on the gates, gate operating components,
tion of training necessary to enable operating
culvert walls, and intake screens may become
personnel to employ the automated measures.
excessive. Also, the transition from stable to
The assignment of these indicators has been
varying water stages in the lock chamber must
based on many observations of operations at a
be accomplished gradually to minimize turbu-
variety of navigation projects. It has been a judg-
lence and oscillation in the chamber. This is of
mental process, and no further discrimination
particular importance for certain older lock de-
between the four levels is attempted.
signs that have the filling/emptying system only
on one side of the chamber. Automated mecha-
NAVIGATION LOCK AND DAM
nisms on the gate operating machinery could be
FUNCTIONS SUBJECT TO AUTOMATION
programmed with the optimum rates for valve
opening or closure, based on experience or ex-
Based on the survey of Corps navigation
perimentation.
projects and the visits to selected locks and
Varying valve operation as a function of chamber
dams, as well as prior familiarity, the functions
stage. At most locks the stage in the chamber is
common to the great majority of lock and dam
varied more rapidly by the lock operator during
projects have been identified with a view to-
the middle of a filling or emptying operation
ward adaptation to automation. Not all func-
than near the beginning or the end of the opera-
tions are present at every navigation project.
tion. In other words, there is a stage-dependence
Discussed below are these functions and the ele-
for the maximum allowable flow rate into or out
ments of each that invite consideration of auto-
of the chamber. With automated control of fill-
mated control.
ing and emptying valves, the amount of valve
opening (and thus the flow rate) could be gov-
Lock operations
erned or moderated, according to a program, by
The various lock operations that may be con-
feedback of chamber stage differential compared
sidered for automated operation are discussed
to upper or lower gages.
below and are shown in Table 2.
Balancing flows between chamber sides. Irregular
and turbulent flows in the lock filling or empty-
Filling and emptying
ing processes can result from significant flow
There are many different designs of filling
differences between the filling/emptying sys-
and emptying systems. All of them, however,
tems on each side of a lock. These may result, for
have certain considerations in common that con-
example, from inherent differences in the effi-
tribute to optimum operation. These include
ciency of the intakes or outlets of the systems, or
keeping stresses and loads on the operating ma-
from differently regulated filling/emptying
chinery within acceptable limits, and minimiz-
valves, etc. The consequence is that excessive
ing adverse currents and turbulence in the lock
turbulence and adverse currents can exist in the
chamber during filling and emptying.
chamber. This condition can place vessel moor-
Timing and monitoring valve movements. For
ing lines under undue loads and can make small
most lock projects the position of filling and
recreational craft difficult to control. With the
emptying valves is shown by mechanical or
flows balanced automatically by means of flow
servomechanical indicators, if it is shown at all.
measurement sensors giving feedback to the op-
These indicators are usually located only at the
eration of the filling/emptying valves, all oper-
lock stands and have no remote readouts else-
ating according to a program, the possibility of
where. Automation equipment on the filling and
adverse unbalanced flow effects should be elimi-
emptying valves would allow valve position
nated.
information to be delivered to any desired loca-
Programming valve operation for various vessel
tion at the project, and would allow valve move-
types. Larger vessels, such as tows, can tolerate
ments to be monitored so as to be input into pro-
more rapid filling or emptying of the lock cham-
grams for other related operations, and vice
ber than smaller craft, such as recreational boats.
versa.
Also, the number of recreational boats in a
Controlling valve opening and closing rates. At
chamber influences the rate at which an operator
most locks the opening and closing of the filling
will fill or empty the chamber, based on the idea
and emptying valves must be performed care-
that the closer the boats are to each other, the
fully to avoid too-abrupt variations in flow
greater the danger for contact in stronger cur-
rates; otherwise, the loading and hydraulic ef-
5
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