Fluid handling – Processes – Cleaning – repairing – or assembling
Reexamination Certificate
1998-09-01
2001-01-23
Walton, George L. (Department: 3753)
Fluid handling
Processes
Cleaning, repairing, or assembling
C073S863720, C073S864630, C073S864670, C138S104000, C138S114000, C137S001000, C137S015040, C137S312000, C114S198000
Reexamination Certificate
active
06176248
ABSTRACT:
DESCRIPTION
1. Technical Field
The present invention relates to a submerged, hydraulic valve actuator with leak protection and a method for detecting such leaks and in one aspect relates to a hydraulic valve actuator of the type used in a submerged location within a ballast water tank aboard a tanker or the like wherein said actuator is encased in a housing so that any hydraulic-fluid leaks are contained therein and wherein such leaks can readily be detected.
2. Background
Double hull tankers are now widely-used for transporting petroleum and petroleum products by sea. It is not uncommon in tankers of this type to use the space between the inner hull and the outer hull as ballast space (i.e. tanks for containing seawater). However, using this space as ballast tanks presents problems when it comes to operating and maintaining the valves which control the flow of seawater into and out of the tanks. Normally, these valves and their respective actuators must be submerged within the tanks, themselves, near the inlet/outlet of the respective tanks and are thereby constantly exposed to the corrosive effects of seawater.
Due to their location, the use of electrically-powered actuators is neither safe nor practical. Further, the location of the valves and the force required to operate such valves also makes the use of purely, mechanical actuators impractical. Instead, submerged, hydraulically-controlled actuators are now in wide use for operating these ballast-water valves. However, the placement of the necessary hydraulic components within the ballast tanks presents a high level of risk for the valve actuators and fittings since they are subject to corrosion which, if left unchecked, can cause the components to fail thus compromising the integrity of the hydraulic system.
For example, if the fittings or the hoses which service the submerged actuators corrode and spring a leak, the hydraulic fluid will leak into the seawater within the ballast tank and will be expelled therewith into the sea when the ballast water is dumped from the tank. As will be recognized, this can pollute the environment and accordingly is unacceptable. Further, due to the submerged position of the actuators within the ballast tank, routine inspection of the actuators is difficult and early detection of failure in the hydraulic system is not likely. Therefore, it is desirable to be able to detect leakage of hydraulic fluid from these actuators at an early stage so that corrective measures may be taken and excessive pollution can be prevented.
SUMMARY OF THE INVENTION
The present invention provides a valve assembly which is adapted to be submerged in a liquid such as the ballast water in a ballast tank of a ship such as a tanker. The valve assembly is comprised of a valve which is movable between an open and a closed position to control the flow of the ballast water therethrough. A hydraulic valve actuator is connected to the valve to move the valve between its open and closed positions. In accordance with the present invention, a fluid-tight housing encloses the hydraulic actuator so that any hydraulic fluid which may leak from the hydraulic actuator or its control lines within said housing will be contained within the housing and will not pollute the surrounding ballast water in the tank. The assembly includes a means for detecting any hydraulic fluid which may leak into the housing.
More specifically, the valve assembly of the present invention is comprised of a valve for controlling the flow of ballast water into and out of a ballast tank of a ship. The valve assembly is submerged in the ballast water and is comprised of a valve which, in turn, is opened and closed by a hydraulic actuator. A housing is positioned over the actuator and is sealed to contain any hydraulic fluid which may leak from the actuator or its control lines within the housing.
The control lines for the actuator are comprised of a first pair of tubes which extend from outside the ballast tank and pass to the actuator through an inlet conduit on an opening in the housing. One of the first pair of tubes supplies the hydraulic fluid to the actuator while the other of the first pair of tubes serves as an exhaust, return line for the power fluid. A second pair of tubes extend from outside of the ballast tank and through the inlet conduit into the inside of the housing. One of the second pair of tubes provides a passage for a purge fluid (e.g. air) into the housing while the other of the second pair of tubes provides a return passage for the purged vapors from the housing. By analyzing the return vapors, it can be determined whether or not any hydraulic fluid has leaked into the housing and the proper corrective measures can be taken.
Both pairs of tubes are encased as a bundle within a single conduit which, in turn, has a flange thereon which mates with a flange on the inlet conduit of the housing. This bundle of tubes within the conduit makes for easy handling while the conduit also protects the ballast water against leakage from the tubes passing therethrough.
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Croke William M.
Levine Robert A.
Faulconer Drude
Phillips Petroleum Company
Walton George L.
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