Stop logs
were originally wooden planks that were set into a groove in a head wall, and
stacked to vary the upstream water level.
Today, most stop logs used in
municipal and industrial projects are made of fiberglass, plastic, or a
corrosion-resistant metal. Stop logs
permit incremental changes in water level that are not possible using stop
gates or slide gates.
Plasti-Fab
has been building stop logs for over 15 years.
The Heavy Duty Copolymer Stop Log has a one-piece molded cover that
totally encapsulates the internal structural steel matrix and has no seams,
glued joints, or cut edges. Water and
chemicals are completely sealed out. Plasti-Fab is the best choice, giving high
quality log at a competitive price. Stop
logs can vary in thickness from 1 inch to 6.5 inches or more, depending upon
the width of the log and the expected head or water depth to be held back.
Stop logs
require individual handling, and for this reason are usually considered for
lower use applications where they may remain in place indefinitely or where
they can be installed briefly during annual maintenance. They do have some special advantages:
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a.
Stop logs require less lifting force than a
large stop gate or slide gate.
b.
They are less costly because an operator,
stem, and associated hardware are not needed.
c.
Stop logs are interchangeable. With careful design, a number of openings can
be built to share and optimize their use.
d.
Stop logs can be designed to close off
openings up to 20 feet wide.
e.
Stop logs can range in height from 6 inches
to 24 inches to more closely control water level. Common sizes will be 12 inches to 16 inches
in height.
f.
Stop logs have an indefinite life cycle due
to FRP resistance to corrosion.
g.
Stop logs operate in extreme environments
well below freezing and above 130 degrees and 100% humidity.
h.
Stop logs are ultraviolet stabilized for
long-term exposure to sunlight.
Stop logs
must be heavier than the buoyant force of the surrounding liquid or they will
float. The weight of the stop log also
provides the only seating force to seal between individual logs. This means all but the smallest logs will
require some type of lifting device to remove them from the guide. Smaller logs, up to 3 feet wide, can be
fitted with stainless steel lifting
eyes, and can be raised by one or two people using lifting hooks. Large stop logs are fitted with stainless
steel lifting pins that protrude from both sides of the log. A heavy duty lift
beam with automatic latching mechanism is recommended for these
applications. The lift beam will be
raised with an overhead winch, davit crane, back hoe, or other convenient tool.
