Fluid Power Services Corp. a Lancaster, N.Y.-based company was awarded a contract by the U.S. Department of Transportation, Saint Lawrence Seaway Development Corporation in September 2005 in excess of $500,000.
This contract covered the design, supply, and installation of new hydraulic systems to control the emergency lift gate that is part of the Saint Lawrence Seaway. This gate is approximately 50 ft. (15 m) high, 85 ft. (26 m) wide and weighs approximately 350 tons (318 t). It is submerged under the seaway just ahead of the Eisenhower Lock in Messina, N.Y.
The contract called for the removal and replacement of the existing hydraulic power units, and providing new proportional directional control valves, counterbalance valves, instrumentation, gauging and system sensors, piping, and accessories for the vertical lift gate equipment to operate as designed.
The existing vertical lift gate controls and associated wiring were removed and replaced with a computer-based control system with system display and data gathering capability and redundant programmable logic control hardware for safety.
The purpose of the gate is to be able to stop the flow of water in the event of a failure or damage by a ship to the normal operating lock gates of the Eisenhower Lock. This lock is the first in a series of locks that can lower ship traffic from the level of Lake Ontario to the Atlantic Ocean. It is for emergency use only but without this gate should a failure or accident occur the level of Lake Ontario would drop approximately 35 ft. (11 m) so it is exercised monthly to ensure it is operational.
The original design used two hydraulic cylinders, 44-in. (118 cm) bore, 9.5-in. (24 cm) rod, 24 ft. (8 m) of stroke. One cylinder was installed on each side of the Seaway and through a series of cables that doubled the stroke of the cylinder the gate can be pulled up from beneath of the Seaway by retracting these cylinders.
The critical part of lifting the gate is that it rises evenly as it could become out of skew and actually be jammed in the guiding provided.
Fluid Power used two separate hydraulic systems, one at each side of the Seaway and each dedicated to one cylinder. Each hydraulic system has a backup pump and drive motor. The gate is raised by a computer with a touch screen for control. Hydraulic proportional direction valves control actual cylinder movement electronically. The position of each side of the gate is continuously monitored via cable-type position transducers that marry into the control system to keep the gate coming up evenly.
The specification called for a maximum out of skew condition of 2 in. (5 cm) over the 85 ft. (26 m) length. Fluid Power was able to maintain level or skew to approximately .2 in. (5 cm), consistently.
It takes 23 minutes to fully raise the gate. Once it is fully up, it can be dogged (locked) in the up position, if required. The computer constantly monitors and displays gate position, hydraulic pressures at the pump and both sides of the lifting cylinders and records gate movement.
The project, which began on Jan. 10, was completed by March 20, for the opening of the 2006 navigational system. CEG Staff