Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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This invent~on rela~es to method and apparatus for removing a
layer of combustible liquid from the surface of a body of water and
more particularly to a method and apparatus for continuously burnlng a
preselected portion of a layer of combustible liqulds on the surface of
a body of water.
In the past, attempts have been made to conflne and collect
the layer of combustible liquid formed by oil spills and the like. It
has been suggested to provide booms to encircle the spill and then to
collect the layer of oil on the water's surface by means of absorbent
material or skimming devices. Some of the suggested boom structures
have difficulty in encircling the entire layer of combustible liquid and
frequently, portion of the layer pass over and under the booms.
Skimmer vessels, as described in United States Patent No.
3,219,190 issued NOvember 23, 1965 to Thune, are suggested to remove the
oil from the surface of the water by a mechanical means and to collect
the oil in collector vessels. It has been found, however, that the layer
of oil is relatively thin as compared with the body of water on which it
is floating and an inordinate amount of water must be removed with the
oil. The water removed is contaminated with the oil and must also be
ZO collected in the collector vessel and disposed of with the oil to prevent
further contamination.
United States Patents Nos. 3,661,495, 3,661,496 and 3,661,497,
all issued May 9, 1972 to Johnson, are directed to processes for posi-
tioning a monolayer of cellular ceramic nodules on the surface of a
layer of combustible liquid and completely burning the layer of combus-
tible liquid therebeneath. These processes provided a method for
successfully burning substantially all of the layer of combustible liquid
beneath the nodules. The processes described in the above-mentioned
patents do not, however, confine the burning to selected areas and the
body of water with the layer of combustible liquid thereon is sub~ect
to the prevailing wind and wave action.
Canadian Patent No. 972,692 issued August 12, 1975 to R.B.
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l~eagler~ provides an improvement to the above-mentioned United States
patents, by providing a generally U-shaped, buoyant, self-propelled
vessel which floats partially submesged in a body of water and has a
longitudinal channel portion with a front opening. The vessel has an
open bottom portion beneath the longitudinal channel portion. As the
vessel advances into a body of water, a band of water with the layer of
combustible liquid floating thereon, enters the channel portion of the
vessel. The rate at which the combustible liquid, as a layer, enters
the channel portion of the vessel is dependent on the forward speed of
the vessel and the speed is controlled so that substantially all of the
layer of combustible liqudd is removed by burning before the band of
water passes under the rear portion of the vessel. As the vessel
advances, the band of water with the layer of combustible liquid moves
through a mixing chamber within the channel portion where a monolayer of
cellular ceramic nodules are positioned on the top surface of the layer
of combustible liquid. The layer of combustible liquid with the nodules
floating thereon, moves rearwardly with the for~ard advance of the
vessel into a combustion cham~oer where the layer of combustible liquid
is ignited and burned. The nodules within the combustion chamber are
recycled to the mixing chamber where they are again positioned as a -.
monolayer on the upper surface o~ the layer of combustible liquid.
Combustion air is provided for the combustion chamber and the combustion
gases may be subjected to a secondary burning in the stack to remove
the combustible materials in the combustion gases and provide a substan-
tially smoke-free waste gas. Apparatus is provided to seal the combus-
tion chamber and mixing chamoer if the burning of the combustible liquid
tends to spread beyond the receiver.
Skimming devices are also known for skimming a floating con-
taminant from the surface of the liquid upon which it is floating and
is particularly applicable in the area of controlling oil refinery
pollution.
~hile skimming apparatuses in general are known to the art,
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many problems are experienced wlth their use. These problems include
the fact that quite often large quantities of water are collected along
with the oil to be gkimmed, thus greatly reducing the effectiveness of
the separation. Weather conditions also often adversely affect the
degree of separation afforded by those devlces now known in the art.
For example, cold weather causes the heavier fraction of the floating
oil to congeal in large masses whlch are dlfficult to collect from
separator pickup surfaces. Furthermore, this semisolid oil often causes
clogging problems in collection troughs and associated piping. Converse-
ly in warm weather the oil spreads out in a thin surface coating thewater and making effective separation difficult. In both cases, exces-
sive amounts of unwatted water are collected.
Canadian Patent No. 825,483 issued October 21, 1969 to L.W.
Lefke et al attempted to provide means to maximize oil recovery while
minimizing water pickup, and to eliminate detrimental temperature effects
on oil viscosity by providing means for varying and controlling the
temprature of the separator pickup surfaces. This was alleged to be
provided by means for guiding a stream of liquid which has a top immis-
cible layer, a bottom immiscible layer and an interface therebetween. A
drum is provided having a serrated hydrophobic pickup surface and means
are provided for rotatably mounting the drum so that its axis of rotation
is so located above the stream that the roots of the serrations of the
hydrophobic surface lie on the interface when the serrations, as viewed
in cross-section, are at their limit of downward travel. Means are pro-
vided for removing liquid from the hydrophobic surface of the drum, the
removing means including a squeegee blade making continuous contact with
the surface of the hydrophobic pickup surface. Means are provided for
varying the rate of rotation of the drum, and means are optionally
provided for controlling the temperature of the hydrophobic pickup
surface.
There are situations, however, which do not favour the use of
the above-described conyentional skimming or burn-off devices for either
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or both of the following reasons, namely: Ca) the quantity of oil is
too large as is possible in the case of an offshore well blow-out;
(b) there is too much wave action.
Accordingly, it is an ob~ect of a broad aspect of this inven-
tion to provide an improved floating device for the recovery of oil
from oil spills.
By a broad aspect of this invention, a floating oil recovery
device is provided comprising: a main platform; a plurality of
radiating float members projecting therefrom, a plurality of concentric
perforated open cylindrical baffles depending therefrom, providing a
plurality of annular passages and a central cylindrical core; a suction
pump disposed within the cylindrical core, the pump being flexibly
suspended therewithin to float with its intake substantially at the oil-
water interface.
By one variant of this invention, the cylindrical baffles are
provided with circular flanges projecting into the annular passages.
~ - By a variation-of this variant,a plurality of vertically
spaced-apart flanges are provided.
By another variant of this invention,:the radiating float
members comprise a plurality of outrigger floats, each supported by an
arm having an elbow capable of articulated adjustment.
By yet another variant of this invention, the suction pump
includes a discharge tube, and the discharge tube is connected to the
pump by flexible means.
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By a variation of this variant, the discharge tube is freely
vertically movable with relation to the main platform.
By another aspect of this invention, a method is provided for
skimming and suctioning spilled oil from a body of water, the method
including the steps of: '(1) passing waves containing the oil spill
through a plurality of consecutive perforated baffles, thereby progres-
sively reducing the height of the ~ave; (2) providing a central collec-
ting core of relatively calm water; ~3) positioning a free floating
.. , . -- . . . _ . _ . . ...................... . . . .. .. . .suctlon device therein, the device having an intake at the oil-water inter-
face; and (4) operating the free floating suction device to suction off
spilled oil in the central collecting core and (S) providing discharge means
connected to the free floating suction device to remove the oil collected by
the suction device.
Thus, the device according to an aspect of this invention comprises
two parts. The first part is a series of concentric wave baffles making up a
unit which is supported by outrigger floats to provide a wide "stance" and
stability. This unit provides an area of chop-free water in the centre where
the second part operates.
The second part is a free floating skimming device which drains off
the top few inches of oil and/or water which is then pumped out to be collected
or burned in an oil-well testburner which can typically accept up to 50%
water. The skimming nozzle is free to follow changes in wave height by being
unrestricted in vertical movement independent of the wavebreaker which sup-
ports it. It can also f~llow the changes in waveslope by being free to tilt
in any direction through the use of a flexible connection. This ensures that
the skimmer's intake remains parallel and just below the water level at all
times. By ad~usting the buoyancy the intake can be kept so that the oil film
can be collected with relatively little water.
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The primary pump can be incorporated into the skimming device
and driven by hydraulics or any other pumping system can be mounted on
the floating wave baffle unit, directly above the ski~mer.
In the accompanying drawings,
Figure 1 is a partial cutaway view of the device of one aspect
of this invention; and
Figure 2 is a section through line II-II of Figure 1.
The floating oil recovery-device, shown generally as 100, is
basically intended to provide a platform for supporting the equipment
necessary to skim and remove spilled oil from a water body. In order
to operate efficiently under adverse weather conditions such as choppy
waters, certain features form part of the construction of the device,
thus providing an adYantage in the operation of the device.'
In order to maintain the'devlce in a stable floating position,
outrigger floats 110 rest belo~ supporting arms 111 which radiate from
the platform 112 of the device.' Supporting arms 111 have an elbow 113
which allows the floats 110 to be rigidly supported from the platform
while the bulk and weight of the'supporting arms 111 is minimized. By
providing a pivotal adjustment to the supporting arms 111, the floats 110
can be lowered or raised to obtain the desired platform height in rela-
tion to particular wave conditions. The elbows 113 also serve the pu -
pose of providing adjustment to the position of the float through arti-
culating adjustments. In a preferred embodiment, the floating device
has four outrigger floats; however, as long as symmetry is maintained,
more outrigger floats may be provided.'
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Referring now to the main body of the floating oil recovery device
100, the platform 101 has a plurality of concentric depending open cylindrical
baffles 114, 116, 118, 120 provided with a plurality of perforations 117.
The baffles are partially submerged below the water surface 115. The spaced-
apart perforations 117 are of suitable size to allow the passage of the oil
infested water into the concentric annular passages 122, 124, 126 between
baffles 114, 116, 118 and 120, respectively. Baffle 114 is provided, along
- its inner wall, with a plurality of vertically spaced-apart downwardly depend-
ing flanges 128, to assist in calming the agitated water as it passes through
perforations 117. Similarly, baffles 116 and ~18 are provided with such
flanges 128 both on their outer walls and their inner walls, and baffle 120
is provided with such flanges 128 on its outer wall.
Within the inner core 121 enclosed by the third baffle 120 is a
relatively calm area where an oil recovery pump 121 is disposed. The pump
is described in copending Canadian patent application Serial No. 253,7~2 filed
June 1, 1976 is suitably suspended from the platform 101 by means of a flexi-
ble connection 123. The outlet pipe 125 is connected to pump 127 by means
of a flexible conduit 129 and elbow pipe 131. Pipe 125 is free to move ver-
tically within roller bearing retainer 133. Thus, any wave
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or turbulent water which strikes the outside surface of baffle 114
continues through perforation 117 towards the pump 121 and ls progres-
sively reduced in height with esch passage through the concentrlc
baffles 116, 118, 120 and contact with the flanges 12~. When entrance
is gained i~to the central collecting area 119, the motion of the water
has been substantiall~ reduced, and the pump 121 is able efficlently to
skim and suction off the oil resting on the surface of the relatively
calm and confined water. The floating pump 121 is furthermore able to
cope with any remaining minor water motion as a result of its flexible
connection 123 and its "free'floating" pipe connection via retainer 133
to the platform 112. The'liquid which is suctioned off is removed by a
conventional pump 127 positioned on the platform 112 driven by motor 135
'' and is disposed of via outflo~ pipe 137 in a burner (not shown).
The entire device 100 can be either towed by a vessel or can
be set up to provide its own motive means.
