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Description  |
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BACKGROUND OF THE INVENTION
This invention is directed to an oil boom and method of deploying and
retrieving the same for an open sea skimmer barge for the removal of crude
oil, refined hydrocarbon product or other floating pollutant slicks for
water surfaces, particularly those slicks caused by accidents while
handling, transporting, processing, controlling, producing or exploring
for hydrocarbons.
For many years, crude oil and refined hydrocarbon product spillages at sea
have been a problem. The environment damage and cleanup costs of large
spills can reach millions of dollars, which along with damaging publicity
present a serious problem for the industries involved. As more crude oil
and refined hydrocarbon products are being transported over longer
distances by larger tankers, and with the increases in offshore
hydrocarbon exploration and production, the problem of dealing with
spillages is likely to increase.
Since crude oil and refined hydrocarbon product spillages are likely to
continue at an ever increasing rate, a method and apparatus are needed for
reliably removing the spillages as rapidly as possible from the surface of
the water in open seas or large bays, lakes and rivers.
Slicks in the open sea vary considerably in their characteristics depending
upon the type of crude oil or refined hydrocarbon product spilled, the
weather, size of the spillage and the condition of the sea. The slick
thickness may vary on the surface of the sea and be considered as having a
portion extending below the surface of the sea due to the continual
degradation of the slick by the elements and natural evaporation of the
hydrocarbons.
When compared with the problems of recovering spillages in quiet, calm
seas, bays, harbors or rivers, the recovery of spillages in the open sea,
particularly under adverse weather conditions, is clearly more difficult.
Open sea spillage recovery requires equipment which must be
self-contained, capable of maintaining its station over long periods of
time and capable of operating in adverse weather conditions, such as in
seas of eight feet or more. Frequently in the past, many types of spillage
recovery equipment have only been effective in relatively calm conditions
and were intended for short term operation.
To date, many types of methods and apparatus have been used in attempts to
deal with spillages.
Detergents and other chemical treatments of slicks have been and continue
to be utilized, but each has limitations and inherent hazards which can be
as undesirable as the slicks themselves.
In the past to confine spillages in specific areas, floating containment
booms were often deployed. The floating booms were either an inflatable
type or had buoyant materials secured thereto and had permeable or
impermeable barriers extending below the surface of the water.
Other types of floating containment booms often employ storage or
deployment devices for the handling and storage thereof. Such typical
types of containment booms are shown in U.S. Pat. Nos. 3,532,219;
3,563,036; 3,664,504; 3,679,058; 3,922,860; 4,076,624; 4,089,178; and
4,123,911.
Yet other types of floating containment booms are utilized to collect and
direct spillages on the surface of the water to a skimming device being
towed by the vessel for the removal of the spillage. Such typical types of
containment booms and skimming devices are shown in U.S. Pat. Nos.
3,612,280; 3,653,510; 3,710,943; 3,983,034; 4,116,833 and 4,133,765.
Another type of prior spillage removal equipment employing endless belt
transports, such as those described in U.S. Pat. Nos. 3,314,540 and
3,314,545, are considered by their design to have a limited capacity to
collect floatage of both solid and liquid forms of the spillage. More
particularly, some prior constructions depend on the adherence of floatage
to the belt transport to recover solid and liquid floating material of the
spillage. Others provide structures that push the spillage to recover the
same, and still others require pumps to enhance the collection of
floatage, such as the belt transport sold by Marco Pollution Control,
Seattle, Wash. Yet others tend at least to partially bulldoze the spillage
being recovered, which increases the likelihood that some spillage will be
pushed to the side and hence not collected.
Another prior skimming type spillage recovery equipment utilizes a
submerged forward lip or edge and processes all the inflow, whether
floatage to be removed or the liquid spillage being skimmed, which is
above the shelf edge. This type of recovery equipment generally takes in
the floatage and liquid spillage which is above the shelf edge, and hence
leaves floatage and liquid spillage uncollected where there is a
considerable depth thereof. This type of arrangement is illustrated in
U.S. Pat. Nos. 3,690,464; 3,875,062 and 3,823,828. This skimming equipment
illustrated utilizes the forward velocity of the vessel and the pumping or
suction action of either the vessel's propulsion means or a separate
pumping means to help enhance the flow of spillage over the submerged
forward lip. Wave action will affect this type of skimming equipment since
heavy seas will cause the excessive inflow of water with the spillage
since the control of the depth of the forward lip below the surface of the
water is difficult. With the excessive inflow of water with the spillage,
it will also become more difficult to subsequently separate the spillage
therefrom, thereby requiring other types of separation equipment or much
larger on-board holding tanks for the excessive water and spillage.
Yet another prior skimming type spillage recovery equipment utilizes a
downwardly inclined member having a horizontal slot or opening at the
lower end thereof to force the slick downwardly during the passage of the
inclined member thereover and into the slot or opening due to the pressure
differential created by the buoyancy of the slick. The pressure
differential may be increased to ensure the slick will flow into the slot
or opening through the use of pumps to decrease the pressure within the
cavity fed by the slot or opening. Typical examples of this type of
equipment are described in U.S. Pat. Nos. 3,465,882; 3,615,017; 3,715,034;
3,860,519 and 3,966,615 and published U.K. Patent Application No. GB
2,005,554. In this type of skimming equipment the skimmer may be
stationary having a flowing body of water moving thereby, as in U.S. Pat.
No. 3,465,882, may be self-propelled through the water utilizing a reduced
collection tank pressure, as in U.S. Pat. No. 3,615,017, may be
self-propelled utilizing a variable flap to control the slot or opening
width and merely utilize a gravity settling technique in the collection
tank, as in U.S. Pat. No. 3,715,034, or may be self-propelled utilizing a
reduced collection tank pressure and a wave-receiving splash plate on the
bow thereof, as in published U.K. Patent Application No. GB 2,005,554.
This type of spillage recovery equipment requires relatively high
velocities downwardly along the inclined member of the spillage relative
to the inclined member, i.e., for example, five to ten knots, for most
efficient operation and also has a tendency to sidewardly deflect a
portion of the spillage, even with the addition of vertical extensions
along the inclined member to prevent the same. As with the submerged
forward lip type skimming equipment, this type of equipment suffers
performance degradation in heavy seas since it is difficult to control the
height of the inclined member with respect to the wave height. Also, since
in open sea skimming operations high forward velocities are required to
maintain the high velocities of the spillage downwardly along the inclined
member with respect to the inclined member, sideward deflection of the
slick and splashing of the slick over the bow of the vessel and large bow
waves created by pushing and churning of the spillage, even in calm seas
let alone heavy seas, are a problem.
Still another type of spillage recovery equipment utilizes a rotating
downwardly inclined endless belt to force the slick downwardly during the
passage of the belt thereover and into a collection tank due to the
pressure differential created by the buoyancy of the slick as it is
depressed. Such equipment is illustrated in U.S. Pat. Nos. 3,314,540;
3,804,251; and 3,812,968. While not necessarily requiring high forward
velocities for skimming operations, such velocities can be artificially
created by increasing the rotational speed of the belts. For open sea
skimming operations this type of equipment may require the use of many
rotating endless belt assemblies, may have problems operating in heavy
seas due to the inability to compensate for wave height variation thereby
having waves break over the vessel on which the equipment is installed,
and may sidewardly deflect portions of the slick during operations thereby
lowering the effective skimming efficiency of the device.
Other types of recovery equipment utilize a combination of slick separation
techniques in order to remove as much water from the spillage in order to
reduce handling and storage problems on board the equipment. One such
device having an initial submerged forward lip to skim the slick, a
plurality of rotating drums to further separate the water from the slick
and a gravity settling processing tank to further separate the water from
the slick is illustrated in U.S. Pat. No. 3,700,107. Another such device
having an initial suction type skimming device, a further gravity settling
tank for a secondary water and slick separation means and finally a
centrifugal type separating means is illustrated in U.S. Pat. No.
3,957,646.
SUMMARY OF THE INVENTION
The open sea skimming barge of the present invention is self-contained,
capable of maintaining its station over extended periods of time, capable
of operating in adverse weather conditions and utilizes a multiplicity of
separation techniques to ensure the most efficient recovery of open sea
spillages. The open sea skimming barge of the present invention utilizes a
unique containment boom arrangement, spillage suction tunnel having an
integral variable flap therein for initial separation of spillage into a
collection tank, a secondary recovery means for further separation of the
spillage in the collection tank and a tertiary recovery means for the
final separation of the spillage for subsequent storage in holding tanks
for offloading.
The present invention and the advantages thereof will be better understood
when taken in conjunction with the following specification and drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side view of the open sea skimmer barge of the present
invention.
FIG. 2 is a partial cutaway side view of the open sea skimmer barge of the
present invention.
FIG. 3 is a partial plan view of the main deck of the open sea skimmer
barge of the present invention.
FIG. 4 is a cross-sectional view along line 4--4 of FIG. 3.
FIG. 5 is a cross-sectional view along line 5--5 of FIG. 3.
FIG. 6 is a cross-sectional view along line 6--6 of FIG. 3.
FIG. 7 is a plan view of the main deck of the open sea skimmer barge of the
present invention.
FIG. 8 is a partial plan view of the main deck of the open sea skimmer
barge showing various lines for oil boom deployment of the present
invention.
FIG. 9 is a side view of one end of the oil boom of the present invention.
FIG. 10 is a side view of the partial line attachment for one end of the
oil boom of the present invention.
FIG. 11 is a cutaway side view of the deployed oil boom of the present
invention and its attachment to the open sea skimmer barge.
FIG. 12 is a schematic diagram of the line attachment for securing one end
of the oil boom of the present invention to the open sea skimmer barge.
FIG. 13 is a top view of the deployed oil booms of the present invention
and their relationship to the open sea skimmer barge.
DESCRIPTION OF THE INVENTION
Referring to FIG. 1, the open sea skimmer barge 10 of the present invention
is shown in its preferred embodiment.
The open sea skimmer barge 10 comprises a hull 12 having a raked bow 14 and
transom stern 16, deckhouse 18, cranes 20, helideck 22, control tower 24,
skimmer control tower 26, oil booms 28 and life boats 30.
The main deck 32 of the hull 12 is constructed having no camber or shear
and the bottom 34 of the hull 12 is constructed having no deadrise. The
hull 1 | | |
