Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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The present invention relates to an apparatus for removing oil from
the surface of a body of water, more paricu]arly to a portable skimming
apparatus.
Oil which is spilled on water has ~een called the most expensive oil
in the world. The cost of removing such oil is not only becoming evermore
expensive, but the expenses of repairing damage to shorelines, boats, and
wildlife is likewise considerable~ One major piece of equipment contributing
to these increased costs is the skimmer employed for removing oil from water.
There has been a trend toward building more sophisticated special purpose
skimmers for use in coastal waters. These are specially built boats fitted
with oil removal devices. Their construction is such that they are not
usually suitable for other work and many of them must be maintained year round
in port. As the search for oil has moved into deeper and more treacherous
waters, these vessels have become much larger to accommodate the higher sea
states, and consequently much more costly. Much of this cost is for the
vessel itself rather than for the actual oil recovery equipment. The high
initial cost of the special purpose skimmer and cost of maintaining it of
course limit the number of these units available. Thus, there is a need in
the art to provide a more cost effective approach to oil spill recovery. It
! 20 is desirable to develop portable skimming devices that fit on vessels of
convenience, work boats, supply boats, fishing vessels, etc. which lessen
the need for specially constructed vessels and significantly increase the
amount of available spill recovery equipment reasonably close to the spill
location.
The present invention in supplying the above noted need provides
an oil spill cleanup kit that can convert many kinds of vessels into temporary
skimmers in a relatively short time. It permits more rapid response to oil
spills which occur in remote areas. Such kits are storable on drilling
platforms, for example, and if a spill occurs in the vicinity, work boats may
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be transformed into skirnmers that immediately begin cleaning up
the spill.
In general, each skimming kit has six components. The
first component is the sock or actual oil skimming device~
Generally, this is a one piece fabrication of rubber or other
flexible material which employs a wave-damping section, an oil
collection section and multiple integral suction ports for pick-
ing up oil. Second, there is a floating frame such as an alum-
inum frame which supports the forward end of the sock and main-
tains it open. It also provides a solid structure for attaching
a tow line. The frame allows the sock to roll and pitch inde-
pendently of the towing vessel. Third, a hydraulic crane is
mounted at one end of each kit to facilitate assembly and de-
ployment of the skimmer. Fourth, a pump and power unit is pro-
vided for hydraulic power to the crane and to a skimming suction
pump. Fifth, a container is provided for storage for all
components. It has the standard dimensions and fittings of a
typical cargo container so that it can be trucked or shipped
easily. The crane is mounted at one end of the container and the
pump and power package at the other. The sock, frame, towable !
bags, hoses and tools are stored in the centerhold of the con-
tainer. After these components are removed and deployed, baffles
fold out from the container walls, and the centerhold becomes
an oil/water separator. Sixth, towable bags are provided in the
event of a large spill, so that oil drawn from the top of the
oil/water separator is piped to the towable bags for temporary
storage.
According to the invention, the apparatus for removing
oil from the surface of water, as above generally described is
characterized in that it comprises an oil skimmer towable
alongside a vessel by tow means connected to the vessel sub-
stantially forward of the skimmer, whereby the motion of the
skimmer is effectively uncoupled from the motion of the vessel;
means for self-floating an open front of the skimmer so that it
freely follows surface water motion; a chamber within the
skimmer for receiving oil and water thereinto which is formed
by (a) the open self-floated front, (b) a substantially flat,
flexible, wave-conformable top which contacts the oil, suppresses
turbulence associated with wave chop inside the chamber, and
prevents the occurrence of an air interface between the chamber
and the oil, (c) an at least semi-rigid, substantially flat
bottom which is of substantial length to arrest orbital water
motion of intercepted waves but not impede water and oil flow
with the chamber, (d) sides connecting the top and the bottom
which extend rearwardly and are so arranged relative to each
other that water flow within the chamber is not substantially
impeded, (e) ties between the sides constraining the top and
bottom to be nearly parallel planes for efficient wave damping,
and (f) a rear extending downwardly from the top and spaced a
substantial distance behind the bottom in order to downwardly
direct water exiting from the chamber, whereby the change of
current direction in combination with turbulence suppression by
the top and arresting of orbital wave motion by the bottom allow
buoyant oil layers and droplets to accumulate in a quiescent oil
capture zone created within the chamber allowing oil to collect
at the top of the chamber for removal therefrom; and means for
removir.g substantially water-free oil from the chamber.
The invention will now further be illustrated with
reference to the accompanying drawing wherein:
Figure 1 is a view of a skimmer and towing vessel
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in operation;
Figu~e 2 is a top view of the skimmer;
Figure 3, which is to be found on the same sheet as
Figure 5, is a sectional view of the skimmer;
Figure 4 is a view of a hydraulic crane, and power
package with a container.
Figure 5 is a view of the container being used for
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separating oil from water recovered by the skimmer of Figures 2
and 3.
In the drawing a preferred embodiment is shown merely
for the purpose of elucidating the invention, which is not
restricted thereto.
In the embodiment shown Figure 1 provides an overall
view of the present invention in use with a conventional work
boat. Skimmer 2 which has
the appearance of a flattened sock with an open front end maintained open by
frame 3 and floats 4 is attached to the work boat by lines 5 which connect
with the boat well ahead of the position alongside the boat whereat the skim-
mer is deployed so that the motion of the skimmer is effectively uncoupled
from the motion of the boat, thereby allowing the skimmer to ~ove freely up
and downg pitch, roll, etc. Inithe prior art where a skimmer or boom is de-
ployed alongside a vessel by a rigid connection, the motion of the vessel is
translated into the skimmer or hoom, causing it to dip beneath the water or
raise above the water and in either case permitting oil to pass thereby, thus
o hindering effective removal of the oil from the water. A bumper (not shown)
is deployable between the skimmer and the vesse] to prevent damage to the
vessel by the skimmer. Lines 6 from the rear part of the skimmer pass oi]
into the container 7 which is employed both as a device for separating oil
and water from the skimmer, as more particularly described hereinafter, and
also as a container for the skimmer and power components used to deploy the
skimmer. Oil lines 8 extend from container 7 to a bag 9 towable behind the
work boat 1 as a convenient means for storing separated oil, especially in
the instance of larger spills which require extra storage space.
Referring now to Figures 2 and 3 of the drawings, a more detailed
view of the skimmer is shown. The skimmer includes floats 20 which are
mounted on opposite sides of a frame 21 which holds the front of the skimmer
open and in a position to receive incoming oil and water. The top of the
skimmer 22 is of a flexible material such as nitrile rubber which flexes
easily with incoming waves. ~ir exhaust ports 24a expel air captured by the
sock and prevent the occurrence of any air space between the top of the skim-
mer 22 and collected oil 23. This makes the removal of oi] from the skimmer
much easier as will be discussed more particularly hereinafter. The skimmer
top 22 is provided with air and foam flotation 24 which keeps the top of the
skimmer above water level and yet does not raise it above the oil level as
above noted. Inflatable flotatiQn 2S is provided around thc sides of the
rear section of the skimmer. The bottom of the skimmer 25 as shown in ~igure
3 is spaced from the top of the skimmer by side walls 27 and ties 2~ which
prevent the top of the skimmer from billowing and further prevent an air
interface between top 22 and collected oil ~3. Top 22 and bottom 26 articu-
late easily with large waves and swells and yet the water motion within the
skimmer is relatively quiescent not only because the top 22 tends to dampen
wave chop but also because bottom 26 intercepts wave particle motion and
prevent orbital water motion within the skimmer which normally would sweep
oil out of the skimmer. The skimmer is also provided with an upwardly ex-
tended lip 29 which prevents wave splashover, particularly in the case of
extremely choppy water. Water and oil entering the skimmer as shown by arrows
in Figure 3 proceed to the rear section 30 which is concave facing toward
the front of the skimmer and water exits at the bottom of the skimmer, the
oil remaining at the top part of the~kimmer with any debris which collects
within the skimmer. me rear of the skimmer may be raised periodically to
allow debris to be discharged. Since an air interface is not allowed between
the top of the skimmer and the oil, the oil is withdrawn from the skimmer by
well point suction, preferably through a number of oil recovery suction
points 31 rather than through a single large suction point. Undesirably, more
water is withdrawn through a single large suction device, particularly one
which is not integral well point suction but which floats on the oil sump and,
in the case of prior art skimmers, moves up and down with wave motion, alter-
nately pulling air above the oil ~ump and then water below the oil sump.
Referring now to Figure 4 of the invention, there is shown a more
detailed disclosure of the ~ontainer 7 shown in Figure 1. Container 7 includes
all the components necessary for use with the present invention. As already
mentioned, it is practical to store the container on drilling platforms to
be near potential spills. If an oil spil] is reported to the platform, the
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device is quickly loaded on board a work boat. The components of the skimmer
can be assembled on deck as the boat proceeds toward the spill and be ready
for deployment upon arrival. After use, the device can be repaired, cleaned
and repackaged to wait for its next use. The kit includes a hinged cover 40
which opens to disclose the skimmer nestled within the container 7, hydraulic
crane 41 which is used to deploy the skimmer from the container alongside a
work boat or other vessel of convenience, crane controls 42 which are employed
to direct the operation of deploying the skimmer, and a power package 43 which
powers the hydraulic crane 41 and other devices necessary for operation of the
skimmer.
Figure 5 discloses the container of Figure 4 in use for separating
oil and water from the skimmer. An oil/water mixture comes from the skimmer
via line 6 and proceeds into a first compartment 50 which is formed by one end
of the container and a solid overflow ~affle 51. Within this compartment oil
col]ects and flows over solid overflow baffle 51 and into one of several
chambers 52 through 54 formed by perforated surge baffles 55. me oil and
water flow through these chambers and into next-to-terminal chamber 56 formed
by one of the perforated baffles 55 where oil is removed by floating suction
head 56 and flowed via line 8 to a towable bag 9 as shown in Figure 1. Water
from the next-to-terminal chamber 55 passes beneath a solid underflow baffle
57 and into terminal chamber 58. A smaller baffle 59 is provided ahead of line
60 which removes clear water from chamber 58. me baffles, except for baffle
59, are all hinged so that they fold against the sides of the container when
not in use and allow deployment of the skimmer and associated components with-
in the container.
While the skimmer of the present invention is preferably employed
alongside a moving vessel, it is apparent that it may also be used in a
stationary position in streams or currents for oil collection purposes with
or without a vessel. Also, it may be deployed between hulls of a catamaran
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vessel. Manifestly, the present invention is useul also for collecting
floating debris and floating liquid pollutants other than oil. Where possible,
multiple skimmers may be deployed on one or both sides of the vessel in use.
The container is useful a]so with other water/oil separation techniques known
in the art. Similarly, the wave damping part of the skimmer of this invention
can be used separately to reduce wave turbulence in front of other types of
skimmers.
For particularly viscous oils an absorbent rope belt (United States
Patent 3,668,118) can be threaded in~o the sock and used in place of the in-
tegral well point suction components. Of course, even though the oil to beremoved is amenable to well point suction, any endless loop sorben-t can be
used in place of well point suction (United States Patent 3,700,593). For
both viscous oils and debris, nets having a suitable fineness can be held in
the water just behind the sock; the rear of the sock can be raised~ allowing
accumulated oil and debris to spill into the trailing net. If the net is
hoisted from the water surface, water drains out and the remaining contaminant
is deposited in the top of the container by a batch process.
