COPOLYMER STOP LOGS

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:

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.

GUIDES Most stop log guides are fabricated using T-304 or T-316 stainless steel.  However, in a few harsh environments or with the smaller stop log designs, a fiberglass guide may be used.  Guide shapes will be similar to the Heavy Duty Titeseal gate, but the seal design has significant changes to compensate for the lack of a mechanical closure, i.e., no stem or operator.  Guides are designed for embedding, surface mounting, or in-channel mounting.  Embedded guides are either attached to the form work and encased with the wall pour, or they may be grouted into a pre-formed blockout at a later time.  Surface mounted guides are anchored directly to the face of the wall, and a 1 inch grout base is used to permanently seal between the guide and the wall.  In-channel guides are mounted and sealed in the same manner to the inside surface and floor of an existing channel.

SEALS This is NO published leakage standard for stop logs.  Any written standard in specifications have been misapplied, usually from AWWA C-501.  In order to satisfy these requirements, it was necessary to develop some entirely new seal designs.  Plasti-Fab has the best stop-log seal designs available on the market today. 

All Plasti-Fab seals are made from virgin molded neoprene that is resilient, long-lasting, and has excellent compression-set characteristics.  The seal between each stop long is achieved using a dual neoprene lip seal that is bonded and mechanically fastened to the top of each log.  This lip or "alligator" seal gives a consistent, firm sealing surface across the entire width of the log, and the compressible lip supplies the flexibility to provide a positive seal. One log in each stack is designated to be the bottom log and is fitted with both top and bottom seals.

To accomplish the more difficult job of sealing between the guide and each stop log, a special "labyrinth" seal was developed.  This seal has two separate seating points for the stop log to seat against.  It is mounted to each side of the channel, using a special stainless or FRP clamping bar, and can be easily removed and replaced if necessary.  This custom seal can be activated with very low heads, and in actual testing has proven to be very effective.

LIFTING BEAM The Heavy Duty Lifting Beam is hot dip galvanized steel, and will be the same length as the stop logs it is designed to raise.  The lift beam is supplied with self-latching swing hooks which engage the stop log lifting pins and hold the log firmly while it is being raised or lowered.  In order to release the log, it must be seated on the stack or floor.  When the log's weight is supported, the tag line can be pulled to release the hooks from the pins and the lift beam can be removed. 

STORAGE When stop logs are not in use, they should be kept nearby in a storage rack of tome type to help protect the seals.  Plasti-Fab has removed much of the potential for seal damage by placing the seals on the top surface of the stop log.  Plasti-Fab offers several convenient storage rack designs.  If no rack is available, then the logs should be set on the bottom edge of the log, or laid flat on their side on a flat surface with spacers in between each log. 

LOCATION Water and wastewater treatment plants, fish hatcheries, CSO facilities, lagoons, flood control structures, diversion channels, sludge-drying beds, composting facilities, and wetlands.  Stop logs also can be found in tank farms and industrial impoundment areas where vehicle access is required and isolation is difficult or impossible by any other means.

WHY BUY PLASTI-FAB?

1.    High corrosion resistance and long life under some of the worst "set and forget" conditions found in treatment plants. 

2.    Copolymer Stop Logs give the engineer and contractor a real alternative to other plastic stop log specifications.

3.    Plasti-Fab has extensive design and application experience with stop logs.

a.    Superior seal designs using superior seal material - neoprene.

b.    Molded construction that totally encapsulates the internal support matrix.

c.     Ability to meet any specified deflection requirement.

d.    Modern materials in lieu of redwood or cypress which is becoming scarce.

e.    If necessary to be competitive, Plasti-Fab will consider quoting aluminum and stainless steel stop logs.

WEDGING TITESEAL® SLIDE GATE

The Wedging Titeseal® Slide Gate was developed and patented by John Vitas at Plasti-Fab. It is the tightest sealing slide gate available on the market today. The Wedging Titeseal® design is capable of reaching extremely low leakage rates. In our literature we say less than 100 cc/mm/foot of wetted perimeter. This is 4 to 5 times lower leakage than permitted by AWWA C-501, and applies to both seating and unseating heads. In actual practice, the Wedging Titeseal® Gates have been adjusted to the point of being nearly drip-tight.

NOTE: There is no top seal on a Wedging Titeseal® Gate so water can flow over the top. The Wedging Titeseal® Gate MUST be taller than the maximum water level in order to be effective.

When requested, Plasti-Fab will run factory leakage tests on any Titeseal® gate, and provide a written report of the results to the engineer or client. Testing must be set up ahead of time, preferably in the specification.

The Wedging Titeseal® Gate is used in many of the same areas and applications as a conventional slide gate. It is frequently used by industries for spill control, emergency shutoff and in aggressive flow streams. Here, the client is willing to pay a premium for the added security and reliability.

An important feature of the Wedging Titeseal® Gate is the location of the J-seals on the face of the gate where they may be adjusted or removed if necessary without dewatering the channel.

The Wedging Titeseal® Gate can be fabricated using 1” thick solid FRP, Sandwich construction, Heavy Duty Copolymer, Stainless Steel, or Aluminum.

LIFTS The Wedging Titeseal® design relies on an operator to achieve a complete mechanical seal. The lift can be operated manually, electrically, pneumatically or hydraulically. The lifts are mounted on the head rail of self-contained gates. A pedestal, bench stand or floor box can be used on gates that are below the operating surface. Pneumatic or hydraulic operators may be used where power isn’t readily available, or the gate needs to be closed quickly, or safety restrictions limit the use of electricity.

GUIDES The Wedging Titeseal® Gate use Plasti-Fab standard FRP pultruded guides that can be embedded, surface mounted or in-channel mounted. The wedging assembly is an integral part of the guide. Surface mounted guides bolt to the face of the wall around an opening. In-channel guides bolt to the inside face of an existing channel. Embedded guides can be nailed to the concrete forms and encased with the wall pour, or they may be grouted into a blockout at a later time.

SEALS A neoprene flush bottom seal fills the bottom groove of the guide, and neoprene J-seals are mounted down each side and across the bottom of the gate. The J-seals are aligned with the fiberglass wedging bar and factory adjusted so that the gate sealing capability increases as the gate is driven down to the closed position. This often results in nearly water-tight performance. This patented seal design is unique in the market today.

LOCATIONS Wedging Titeseal® Gates should be considered in any area where high performance gates are required. This gate is used often for industrial spill containment or emergency shut-off at airports, military and other Federal sites where performance is critical.

 WHY BUY PLASTI-FAB?

1.    The patented seal design is unequaled in leakage performance. Published leakage rates of 100 cc/minute/foot of wetted gate perimeter.

2.    The unique seal design allows for seal adjustment or removal without dewatering a channel.

3.    For unusual or especially tough applications Plasti-Fab has experience with a large variety corrosion resistant high performance metals and resins.

4.    The Wedging Titeseal® Gate will perform when needed for emergency shut-off, spill containment or any other critical shut off situation.

5.    Plasti-Fab’s experience with customer requirements will help you get the job done right the first time.

6.    Fiberglass gates are lightweight and easy to install.

7.    After the gate is raised slightly, the seal is no longer in contact with its seat. This eliminates seal wear and makes the gate easy to operate.