Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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This inven-tion rela-tes -to a novel flexible
floating boom for co~taining surface contaminan~ts on bodies of L
wa-ter, and in par-ticular to an oil containment boom having the.
Eloa-ting means disposed -therewithin. I-t also relates-to a noveI
method for con-taining oil spills.
Wit`~ the trem~ndous rate of industrialization that i8
taking place throughout the world, pollutlon oE bodies of wa-
ter by oll 9pills iS reaching critical proportions. Not only
are ma~or oil spills occurring, such as when an oil tanker is
wrecked, but also minor oil spills are a daily occurence
throughout the world. Many different systems are being test-
ed for removing the effects of these oil spills and one of
the most successful techniques has been to contain these r
spills by means of booms and then to collect the contained L
oil from the surface of the water, e.g., by skimmers. Such
oil booms can be used not only for containing a major oil
spill but can also be used for isolating terminals from a
permanent installation, temporarily encircling tankers whichL
are being loaded and unloaded, sweeping port areas for re-
moving floating patches of oil, protecting beaches, etc. In
order to provide the necessary versatility, these oil booms
must be inexpensive, light and easy to store and handle.
One such oil boom is in the form of a flexible fabric
curtain wall which floats in the water with part of the CUL'-
tain wall extending a distance below the water surface and a
part extending above the water surface. Some of these flexi-
ble booms are supported in the water by means of separately
attached floats. Spaced vertical stiffeners are provided to
maintain the boom in the necessary vertical position and they
are stabilized by means of~weights along the bottom submerged
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edge. These booms are made up and sto~ed in convenient sec-
tions, e.g. of about 100 feet in length, and when needed are
:t.ached totether aDd deployed in the water to :urround and
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contain the oil spill.
When such booms are used in adverse sea and wind con-
ditions, the~e is a tendency for then to fail because of
tearing under the strain of the sea or ice conditions and
also a tendency for the attached floats to be torn away, or
damaged, thus allowing the boom to become submerged in cer-
tain areas and consequently defeating the entire purpose of
trying to totally contain the oil spill. Accordingly, there
is a very great need for a flexible oil boom system which
will be very inexpensive to produce, easy to handle and yet .
have sufficient strength to withstand adverse sea and wind
conditions as well as to withstand any serious damage from
ice floating on the surface of the water.
Canadian Patent No. 906,772 isgued August 8, 1972 to
R.A. Fossberg attempted to solve such problem by providing a
flexible oil boom comprising a curtain wall of sheet material
having an upper portion and a lower portion. These upper and
lower portions are joined together by an overlapping connec-
tion at a location below the water line. At spaced locations
along the length of the ~oint between the upper and lower
portions are positioned flexible straps which surround the
lower edge of the upper portion and pass through the over-
lapping connection between the upper and lower por$ions so
that the straps provide extending ends on either side of the
boom. These straps are used for connecting the float mem-
bers to the boom. The upper edge of the boom is preferably
formed with a longitudinal pocket which contains a strength-
ening rope and a similar longitudinal pocket with strength-
ening rope i8 also preferably ptrovided at the bottom edge.
Vertical pockets are also provided along the boom at longi-
tudinally spaced positions and these pockets contain sti~-
fening members for holding the boom in a vertically upright
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position.
It is frequently necessary to skim oil slicks in har-
bour areas. However, present skimmers encounter considerable
resistance in being towed through the water and are difficult
to handle. It has also become desirable to contain oil slicks
resulting from underwater leaks or leaks from injured vessels.
However, the great majority of boom systems proposed for such ~;
use survive for less than a day in rough seas. In addition,
many of the more rigid boom systems do not conform to the con~
tours of the waves sufficiently fast to prevent the passage
of oil beneath sections which are left hanging in the air.
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Canadian Patent No. 912,293 issued October 17~ 1972 to C.L.
Kain attempted to provide a solution to such problem by providing a
flexible boom comprising at least one elongated flexible floatation
unit, a flexible weighted net supported in a substantially vertical - `
position by that at least one elongated floatation unit when the boom
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is placed in a body of water, at least one layer of flexible filtering
material, that layer of flexible filtering material being associated
with the weighted net to conform generally to the vertical positioning
and movement of the weighted net, the layer of filtering material being -`
formed of hydrophobic, oleophilic material having a plurality of
passageways therethrough permitting the flow of water through the boom
while preventing the flow of liquid hydrocarbonaceous matter through
the boom.
Another problem attendant in the use of such booms is that the
basically heavy and bulky nature of such known booms make both the
storage and handling thereof diEflcult. By the same token, notwithstan- ;
ding the weight and bulk of these retainers, such often incorporate a
relatively low tensilve strength, both in the individual sections and in
the joining portions, thus limiting the lengths which can be effectively
used, both as a standing barrier and as a towed gathering unit.
Canadian Patent No. 912,294 issued October 17, 1972 to C.E.
Renner attempted to provide a solution to such probIem by providing such
a boom comprising an elongated depending skirt having upper and lower
edges9 a float section defined longitudihally along the upper edge of
the skirt, a ballast section defined longitudinally along the lower edge
of the skirt9 a first male joining end defined at one end of the retain-
er, a second female joining end defined at the second end of the retainer,
the female joining end being of a size and configuration so as telescopi- `
cally to receive the male end of an adjoining retainer3 means associated
with the ends for interconnecting a pair of telescoped ends, the retain-
er being formed of an elongated flexible sheet longitudinally folded to
define a skirt forming pair of adjacent panels bounded along the upper
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edge by a longitudinally extending enlarged pocket constituting a por-
tion of the float section, and a relatively smaller longitudinally
extending pocket along the lower edges of the panel for the reception
of ballast, the second pocket constituting a portion of the ballast
section, means for securing the skirt defining panels together along
substantially the full length thereof, float means received within the
first mentioned pocket, the float means/ ballast and securing means
terminating short of the second female joining end for enabling the
reception of the first male joining end therein, a pair of cooperating
securing collars, one collar mounted on and surrounding the float sec-
tion adjaceDt each end of the retainer, the collars each having an inner
edge fixed to the float section and an unsecured outer edge directed
toward the corresponding end of the retainer, the collars being adapted
telescopically to engage with the corresponding collars on adjacent ` -~
retainers upon an interengagement of the male and female joining ends
thereon, and means associated with the collars for interconnecting a
pair of telescoped collars.
Other problems are inherent in the use of such oil barriers.
The thickness of an oil slick ma~ vary from a mere fraction of an inch
up to a foot or more in thickness. Therefore the barrier must extend
to a sufficient depth to avoid the passing of the oil beneath the
barrier; the probability of this passing of oil is increased by the
action of each of waves and swells of normal sea action or as caused by
passing vessels, including large cargo ships and ocean liners. However,
as the depth of the barrier increases, a larger float is required, and
particularly a material of substantially greater strength is required
which will withstand the great force of wave and swell action as well as
withstand the bombardment by miscellaneous trash-missiles, for example
including objects up to the size of telephone poles. ~- -
Another problem arises from the fact that many materials tend
to sink or to disintegrate when they become saturated with oil or
water. Oil in particular results in extensive degradation. Thus the
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material must remain afloat, and must be oil-resistant.
Another problem is that an oil barrier which might overcome
some of the abuve and other problems would normally be highly expensive,
complex, and too bulky to be of practical value in most instances.
Canadian Patent No. 914,435 issued November 14, 1972 ~o TØ
Bogosian attempted to solve such problem by providing a buoyant barrier
boom comprising a substantially rigid sheet-structure comprising a
first sheet of a substantially oil-resistant synthetic composition and
closed-cell foam composition attached to the sheet-structure in a manner
whereby that sheet-structure 10ats when placed in water in a substan-
tially vertical position relative to the water~s surface and whereby
about one-eighth to about two-thirds of the first sheet extends above
the water surface at least about O.S foot and extends below the water's
surface at least a sufficient depth to maintain the sheet in the sub-
stantially vertical position, the depth being at least about one foot.
Yet another problem inherent in the use of such floating booms
was that some such booms allowed oil to escape both under and over the
boom when used in the open sea or in rough water due to the wave action
and instability o-f the boom~
~anadian Patent No. 936,372 issued November 6, 1973 to N.P.
Cerasari purported to solve such problem by providing a floating boom
comprising a plurality of connector cables, a plurality of upright
support members attached to the cnnnector cables, the upright support
members having a first curved end portion inwardly disposed towards the
oil spill being contained or collected and a second weighted end portion,
a buoyant support tube attached to the upright support member, the
buoyant support tube being attached to the upright support members~ the
buoyant support tube having a valve means for inflating the buoyant
support tube with compressed gas from a source of such gas, and a barri-
cade wall material for collecting and containing the oil attached to the
upright support members~ the connector cables being adapted to be
attached to at least one seagoing vessel to position the floating boom
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around an oil spill to fo~m an oil ~arricade to contain or
collect the ~il spill.
Moreover, nowhere is the threat to the environment
more acute than in the northern oceans where rough seas and
heaYy ice conditions increase the magnitude of the problems
as~oclated with controlling oil spills, and where potential
damage to the environment may have lasting and severe impli-
cations.
Although as described above numerous oil containment
booms have been proposed, none are able to cope with condi- ~
tions encountered in ice infested, choppy water, and in areas i -
where there is dominant breaking wave action by the seas ~
forming white capped waves. - -
One of the problems with booms in steep choppy waves
is the difficulty in making a boom respond quickly to such
fast rising waves. Even if the boom follows the wave itself,
it is almost impossible to make it respond to the breaking
whitecap and have it buoyant enough to rise fast and high
enough to keep above and catch the whitecap which is of less
density, containing both water and air. Consequently, such
waves have a tendency to break over normal booms, carrying
oil with them.
It has been found that, in ice, a boom with external
tension lines and with external floaing attachments traps ice
bearing down on it and, being unable to release the pressure ~ -
exerted by the drifting ice, allows forces to build up until
either the boom or the mooring system breaks, thereby making
the boom ineffective.
It is therefore an ob~ect of one aspect of the pre-
sent invention to provide an oil containment boom which is30
able to contain the oil-impregnated white cap and spray found
in breaking water, and is able to return the polluted water
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from the whi-te caps to -the contained area.
It is an object of another aspect of the
present invention to provide an oil containment boom having a
minimum of exposed sec-tions which migh-t interfere wi-th floating
ice and which minimizes a buildup of ice on -the ex-terior and `
in-terior of the boom.
lt is an object of yet ano-ther aspect of the present
invention to provi.de an oil containmen-t boom which will deflect
and which will, -thereby, allow passage and escape of floating ice
from -the confined area but will rapidly return to its normal
position for containment of oil on -the water surface in the
designa-ted area. - ~ ~
It is an object of yet a further aspect of the r
present invention to provide an oil con-tainment boom which can
be easily stored away on a storage reel after being deflated
-to a minimum.storage size.
By a broad aspect of this invention, an oil
containment boom is provided comprising an elongated member f it
generally V-shaped cross section including a fron-t wall sec-tion
and a rear wall section joined together along respective lower
edges; ballast means located at the join-t between the front
and rear walls for normally maintaining said elongated member
upright; float means disposed between said front wall and
said rear wall at a predetermined and preselected level above
said join-t; liquid deflecting means posi-tioned above said float
means and secured to said front and rear walls in a watertight
manner to form a catch basin in the upper portion of said boom
so that li.quid is prevented from entering said boom below the
~ level of liquid deflec-ting means; and drainage means within one
of said walls adapted to permi-t liquid which is trapped within
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. saicl ca-tcll basin to escape -therefroln-to a ]ocat.;on outside o:f .~-
one oi said walls.
By one varian-t, the liguid deflec-til~~g means
comprises a collap6ible membrane.
By another variant, the liquid deflec-ting means
:is cl:i.spose(l at an angle such -tha-t all -trapped liquid is caused
to be drained from said catch basin.
By a further variant, the float means is a
pneuma-tic -tube, and further comprislng valve means ~or inflating
and deflating said pneuma-tic tube,.so -that said float is
easily collapsible for convenient storage of sa:id boom.
By yet another variant, the float means is
subs-tan-tially centrally positioned within said V-shaped compartment .
-to allow substantially half of said boom to be posi-tioned below
-the surface of -the water. . ~ .
By a further variant, the drainage means
comprises a flap valve.
By yet another variant, -the ballast means ::
comprises a lead weight sewn to the lower edges of said front
20 wall section and said rear wall section. ;
By yet a further variant, the front wall section
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is lower than said rear wall section.
By another variant, the front wall section includes
a f.lexible resilient section along its top to permit inwardly
directed waves to enter the inside of the boom a~ov~ said
col.l.apsible membrane means.
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It will be observed -that the V-shaped boom
adds another dimension -to the barrier that the whitecap must
get over, Breaking whitecaps will to a large extent roll ~-
s-traight over the forward wall into the V-shaped catch basin
and will drain back ou-t into the contained polluted area. Spray
will be caught by -the higher wall on -the downs-tream side.
Moreover, -the floata-tion material is preferably
protected from con-tact with the ice. The exposed surface of the r
boom is devoid oE any pro-trusions so as to cause a minimum
of drag or interference wi-th external flotsom or jetsom.
In one variant, since the float means is
inflatable, storage of the boom is facili-tated, s~nce the boom
can be defla-ted and rolled onto a large storage reel to be r
subsequently s-towed aboard a vessel, thus minimizing storage
space.
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The boom is also ~esigned to be ro-tatably
deflected by floating ice to allow ice to escape beyond -the
confined area and -then -to be au-toma-tically returned to its ;~
normal oil spill retaining boom position, thereby providing
a novel me-thod for oil containment. Thus, these booms which have -the
tension in-tegral in -the ma-terial i-tself, have a tendency -to
roll up on-to the ice, le-t the ice pass underneath and re-en~er
the water when -the;ice has passes through or by. Although some
oil will obviously be lost during this ac-tion, i-t is s-till of
advantage to lose, e.g., 500 gallons of oil, but still have the
boom intact and operable to trap the next e.g., 50,000 gallons
of oil.
In the accompanying drawings, r
Figure 1 is a transverse cross-section of the
boom of an aspect of this invention;
Figure 2 is a trans~erse cross-section of the
boom of an aspect of this invention in its deflated condition;
and
Figures 3a, 3b, 3c, 3d and 3e are schematic cross-
sectional views of a sequence of operatlons showing operation ~-
in ice-infested waters.
Referring now to Figure 1, "V" shaped oil
containment bason is shown indicated generally a-t 9 is shown
including a front wall section 10 and a rear wall section 11
disposed about the floatation means, namely lnflatable float
13 provided with an air valve 131. ~alls 10 and 11 are disposed
tangentially in relation to the float means at approximately
the mid point of the height to permit the approximate lower
halves of the fron-t wall section 10 and the rear wall sec-tion
11 to be positioned below the normal level 50 of the water surface.
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The lower sec-tions of the fron-t wall 11 and -the rear wall 11.
- converge and meet at an apex 12. Disposed between and connected
to walls 10 and 11 is a.lead ballast 14 for main-taining the
V-shaped floating wall sections in a
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basically vertical posltion while in water, with its apex 12
pointing downwardly.
The top dlverging walls 10 and 11 rise beyond the in- -
flatable float 13 to a position approxlmately equal to the
length of the wall sections 10 and 11 displaced below the
water surface. A float harness 15 is secured at approximate-
ly the ver~ical mid point of the interior f ace at longitudinal
area 51 of front wall section 10 and of the interior face
at longitudinal area 52 of rear wall section 11, and forms
an inverse V-shaped harness adapted to straddle the inflata-
ble float 13, thereby providing support for the wall sections
10 and 11. Conventional means are used to adhere the har-
ness 15 to the float 13.
Positioned and secured along the entire length of
front wall 10 at longitudinal area 53 is membrane 16, which
is secured to the front wall at a position slightly above
the float harness 15. Membrane 16 extends across float har-
ness 15 to the rear wall section 11, where it ls similarly
secured along the entire length of the wall, but at a point
a longitudinal area 54 substantially~ higher than the point
where the membrane 16 is secured to the front wall 10.
Positioned along the front wall directly above the
longitudinal area 51 but below longitudinal area 53 where
the membrane 16 is secured to the front wall 10 are drain
holes 17 provided with flap valves 18. The flap valve l8 is
of conventional type that is it functions only to allow an ,
outward flow of water from between walls 10 and 11 towards
the outside of front wall 10. In one embodiment front wall
section 10 has an inwardly curving top section forming a
wave catch 101 exten-ding along the entire length of the
front wall section 10, thereby making the front wall 10 sub-
stantially lower than the rear wall 11 while at the same ~ime
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subs-tantially preventing escape of turbulen-t water over the
wall 10. The upper portion of rear wall 13 above longitudinal
area 54 provides a higher wave catch 132.
As a result of the above construction, the V-shaped
oil containment boom 9 is set up to perform certain desirable
functions. In its ~rmal set up as shown in Figure 1, the
boom is used primarily in areas where there are rough seas,.
arld where breaking waves 55 and whi-te-capped waves 56 are
common, such as, for example, near shore or o-ther shallow
areas and where a breaking wave 55 contains oil par-ticles sus-
pended in the foam and spray part of the wave. By one aspect
of this invention, the "V" shaped oil con-tainmen-t boom 9 is
able to collect the oil suspended in the spray and return it
to the confined area with a minimum of interference with
any of the par-ts of the boom. Wave catch 101, being slightly
lower then rear wall 11~ permi-ts the wave 55 to break over
the -top curvature, -thereby trapping the whitecap 56 and spray
within the V-shaped cavity or catch basln 110 formed between
-the front wall 10 and the rear wall 11. The oil laden spray
is restricted to cavity 110 by the impervious membrane 16,
thus guiding return to the confinemen-t area at the ocean only
through drain hole 17 andby means of flap valve 18. The normal
water level of the polluted water is designated 57. At no time
during the time that the oil is collec-ted from the whitecaps
and the spray and is re-turned to -the confined area does the
oil come in contact with -the inflatable float 13, the float
harness 15 or the inside compartment 120 of -the lower submerged
half of the V-shaped boom. Thus, it is seen that the oil and
sludge is prevented from clogging up, eventually weighing down,
30 ~,: and submerging the boom -thèreby rendering i-t ineffective. Since
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in a preferred embodiment of this invention the faces of front wall
10 and rear wall 11 are poly-
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~-~ vinyl-chloride coated, accumulation of oil and sludge on -the
exposed surface is further minimized.
The advantages,discussed above have been based on
construction features of aspects of -this invention which make
-the V-shaped boom inheren-tly light weight. Therefore, storage
shou].d be relatively easy. To facili-tate further -this storage
operation, Figure 2 discloses an embodimen-t of the invention
wherein -the inflatable floa-t 13 has been defla-ted wi-th -the use
of air valve 131. Consequently, it is now possible -to converge
-the -two wall sections 10 and 11, thereby making -the boom flat
as a sandwich of -two walls 10 and 11 as outer layers and the
deflated floa-t 13, harness l5, membrane 16 and ballast 14
therebetween. The boom is therefore easy to roll up by
conventional means, for s-towage aboard a ship.
The present invention in another of its aspects
is also adapted to operate as shown in Figure 3, namely in the
schematic sequences of Figures 3a, 3b, 3d and 3e. If a large
floa-ting object, e.g., ice float 301 is being retained by the F
boom 9, a great deal of pressure is exerted on the various par-ts
of the boom 9 and the risk of severing the boom 9 is quite grea-t.
The resulting loss of oil would then be significant. Due to the
construction of aspects of this invention, the V-shaped boom 9
has the floating means, namely infla-table float 13 positioned
approximately in the vertical centre. Lead ballast 14 main-
tains the boom in its normal upright position, and -thus pre-
vents rela-tively small particles as well as the oil from escaping
from the confined area. However; if a large floa-ting object
such as, for example, large sections of floa-ting ice 301 become
confined and press against the boom, the sequence in Figures 3a-
3e shows how -th@ boom perm~ts escape of the large ice sections
with a minimum loss of oil. When encoun-
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tering the ice, the boom is lifted above the lce by being
rotated about the horizontal axis 302 of the inflatable float
13 as seen in 3a~ and 3b. Axis 302 is slightly above the le-
vel of the water. Since there are no external points to in-
terfere with the ice 301, the boom 9 is allowed to slip over
the ice as seen in 3c Once the ice has passed, as in 3d
and the boom is free to return to its normal position, as
shown in Figure 3e.
Admittedly, a small amount of oil escapes from the
confined area along with the ice while the V-shaped baom is
temporarily elevated above the water surface. Howev~rj this
amount of escaped oil is insignificant when compared to the
oil that could be lost if the boom was severed completely.
This situation would be even more hazardous in rough seas,
where the oil is likely quickly to disperse on shift from one
area to another much more quickly.
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