Note: Descriptions are shown in the official language in which they were submitted.
The present invention is directed generally to an
apparatus and a method for recovering oil from the surface of
a body of water.
BACKGROUND OF THE INVENTION
In these days of giant oil tankers plying the seas
there is an increasing danger of spillage of crude oil onto the
surface of the oceans or inland waterways either -through
accident or mistake. There have already been enough such
spillages for environmentalists to see that the damage to the
ecology can be devastating when a spillage occurs and the spille~
oil reaches shore. Additionally, the economic consequences o
oil spillages are far~reaching, both from the standpoint of the
losses incurred and the expense of attempting to recover the oil.
There have been many attempts at achieving an effective
apparatus which will ecQnomically and efficiently recover oil
following a spill. Such apparatus should be economical to
produce, be readily transportable to the spill site, be
relatively easy to operate and be efficient in its operation,
Several versions of oil skimming devices have been tried, such
devices using a conveyor or other such apparatus to convey oil
from the water surface upwardly to a waiting tank, Crude oil is
extremely viscous and has the unwelcome property of sticking
securely to almost anything it contacts. This leads to unending
problems with conveyor-type recovery devices as they soon become
clogged or bound by the oil itself.
One attempt at utilizing the properties of crude oil
for recovery thereof is found in Canadian Patent No. 998,624
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issued October 19, 1976 to Olsenl That patent teaches the
utiliæation of a number of floating cells having openings
adjacent the -top through which an oil/water mixture passes
by wave action into -the cells. The mixture is pumped from
each cell to a holding tank on board a ship or a barge.
In the holding tank the oil floats to the ~op and uncontaminated
water is returned to the sea through a bal:L float control
valve by gravity. This device thus makes use of the lower
specific gravity of the oil to achieve separation but it
also has drawbacks. For example there is no control over the
amount of oil/water mixture entering the cells as dependence
is made on wave action to cause the mixture to enter the cells.
Also the action of the cells and the subsequent pumping
operation will result in unwanted emulsification of the oil in
the water, making separation more dificult.
SUMMARY OF THE INVENTION
The present invention is similar to that of Canadian
Patent No. 998,624 in that it utilizes the lower specific
gravity of the oil to achieve separation. However, the present
invention permits a controlled flow of oil/water mixture to a
recovery unit, not being dependent on wave action; does not
require a separate ship or barge to carry a holding tank; and
reduces the chance of emulsification of the oil, permittiny more
efficient recovery thereof.
The present invention utilizes a collection unit
which very simply entails a vertically oriented retaining wall
of generally U-shape which funnels the oil/water mixture from
the mouth thereof as it is towed through the water to a con-
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centration area defined by the wall, A recovery unit is
towed by the collection unit and entails a vertically oriented
open ended cylinder having portions above and below the water
surface. A conduit leads from below the concentration area and
exits in~o -the lower portion of the cylinder, below the watex
surface, the conduit being oriented to induce a circular flow
within the cylinder. A pump in the conduit draws the oil/
water mixture from the concentration area and pumps it to the
cylinder~ In the cylinder the oil floats to and accumulates
on the surface of the water therein and uncontaminated water
is forced out of the open lower end of the cylinder. Proto~types
of the invention have shown that there is very little emulsifica-
tion of the oil and hence almost 100% recovery of oil from the
oil/water mixture passed therethrough, There is control of the
amount of oil/water mixture passed through the apparatus and o
course there is control of the passage of the apparatus through
the oil spill as the apparatus may be towed by an oil spill
containment boom and the boats deploying it. Once the cylinder is
~ full it may be replaced by an "empty" recovery unit or it may be
; 20 emptied into any suitable larger receptacle as might be contained
in, for example, a tanker ship or barge.
Broadly speaking therefore the present invention may be
seen as providing a method of recovering oil from the surface of
a body of water including the steps of: (a) moving apparatus
comprising a collection unit defining a concentration area therein~
a recovery unit having a vertically oriented open ended cylinder
mounted therein with upper and lower portions extending above
and below the water surface respectively, and
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a submerged pumping unit including a pump-containing conduit
leading from the concen-tration area to an opening in the '~
lower portion of the cylinder, through the oil contaminated
water; (b) operating the pump to draw an oil/water mixture
from the concentration area into the conduit; (c) continuing
operation of the pump to force the oil/water mixture through
the conduit and into the cylinder; and (d) flowing the oil/
water mixture generally tangentially into the cylinder below
the water surface whereby oil from the mixture will rise to '
and accumulate on the surface of water within the cylinder and
uncontaminated water will flow downwardly through the lower ,~
open end of the cylinder. ,
The above method may be effectively carried.out in :~
accordance with the present invention by way of appaxatus for
recovering oil from the surface of a body of water comprising
a collection unit, a pumping unit and a recovery unit, the
collection unit including means for deflecting an oil/water ~,
mixture into a concentration area therein, the recovery unit
including generally vertically oriented open ended holding
means having a lo~er submerged portion, and the pumping,means
including submerged conduit means leading from the concent.ration ~,
area -to an opening i.n'the submerged portion of the holding means
and containing pump means therein operable to contirluously draw a
quantity of the oil/water mixture from the concentration area :
and to feed the quantity through the conduit means to the .
holding means, ~hereat oil floats ~o and accumulates on the surface
of water in the holding means and uncontaminated water exits
from the open lower portion of the holding means. .
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BRIEF DESCRIPTION OF T~E DR~WINGS
Fig~re 1 is an elevation, partly in cross-section of an oll
spill recovery apparatus of the present invention.
Figure 2 is a plan view of the apparatus depicted in claim 1.
DEiSCRIPTION OF TEE E`I~EFE~R~æD EMBODIMENT
ST~UCTU~OE
The oil recovery system of the recovery :invention is designated
by the reference number 10 and it includes three basic components, namely a
collectian unit 12, a recovery unit 14 and a pu¢ping unit 16. The collection
unit 12 is connected via the pumping unit 16, to the recovery unit 14.
The collection unit 12 will ke descriked first of all with
reference to bo-th fig~res of the drawings, A retaining wall 18 is shcwn
as being vertically oriented and as ex-tending above and below the water
line W. The re-taining wall has a yenerally U-shape and is n~de up of a pair
of opposed side walls 20 which may be parallelito each other or may diverge
outwardly from the curved wall 22 which connects the walls together along
one vertical edge thereof. The opposite vertical edges of the walls 20 define
therebetween an open mouth area M which is spanned by a coarse mesh scree
24 which has upper and lower portians akove and below the water line
respectively to irlhibit the entry of debris into the collection unit while
still permitting the oil on the water to pass into the collection unit. At
the water surface and generally in the vicinity of the cen-ter of curvature
for the curved end wall 22 is a concentration area C, the significance of
which will become more readily apparen-t hereinbelow.
A flotation bcom 26 extends along the outer surface
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of the retaining wall ~ and is intended to maintain the
retaining wall in its preferred orientation as discussed
above. The flotation boom is generally rectangular in cross-
section and may tc~ke the form of a metal casing containing
flotation material such as an expanded cellular foam. By
using a metal casing to contain the flotation material it
~ is possible to attach other elements to the boom 26 and the
; flotation boom adds structural rigidity to the collection unit.
~he flotation boom 26 has a curved portion 28 which
; 10 follows the curved end wall 22. A plurality of curved,
vertically oriented recesses 30 are provided in -the ou~ermost
vertical surface of the curved portion 28 and each such recess
contains a rotatable resilient bumper roller 32 such that a
portion of the outer surface of the roller 32 projects out-
wardly of its recess. Each roller is mounted on a vertical
shaft which in turn is connected to the metal casing at each
vertical end as at 34. The rollers 32 serve to buffer any
relative movement between the flotation boom 26 and a second
air-filled boom 36. The rollers also serve to maintain a
space between the booms 26 and 36 so as to avoid damage to ;
the boom 36 which might occur if the two booms were to ~ub
together,
The boom 26 is also provided with a relatively deep
well 38 situated in the curved portion 28 and on the
longitudinal center line of the unit 12. At the base of the
well is one half of a ball-and-socket joint which will be
utilized in the towing of the recovery unit 14 behind the
collection unit 12 as to be discussed hereinbelow.
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The inner wall of the flotation boom 26 mounts
bearing means such as a pair of journal or pillow blocks 40,
which blocks are mounted on an axis which is perpendicular
to the longitudinal axis of the collection unit 12. Each
pillow block 40 supports one end of a stub shaft 42, the
opposite end of each stub shaft 42 being affix2d to a support
ring 44 normally situated below the water surface. The ring
44 may thus pivot on the axis of the stub shafts 42.
A central support ring 46 is concentrically located
within the support ring 44 and has diametrically opposed
mounting bars 48 secured thereto. Each bar 48 is pivotally
attached to the outer support ring 44 as at 50 along the
longikudinal axis of the collection unit 12 whereby the
central support ring is pivotable about the longitudinal axis
of the collection unit. Within the central support ring 46
is slidably disposed an elongated sleeve 52. A control yoke
54 is pivoted at its apex 56 to one of the bars 48 and at the
opposite end of each leg 58 to the sleeve 52, on an axis para~lel
to the axis passing through the pillow blocks 40. A cross-bar ;~
60 is secured.to the legs 58 adjacent.the apex and is attached in
a conventional manner to ~he piston rod of a water impermeable
pneumatic cylinder 62 mounted on the bar 48 between the apex :~
56 and the central ring 46. Actuation of the cylinder 62
will have the effect of pivotting the yoke about its pivot
connection to the bar at the apex 56 whereby the sleeve 52 will
slidably raise or lower within the central ring 46.
The recovery unit 14 will now be described with
reference to the two figures of -the drawings. As seen
particularly in Figure 2 a pair of flotation tanks 64 is
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provided As with the flotation boom 26 the tanks 64 may
be formed of metal and contain a suitable flotation material.
Desirably the tank 64 will have a boat-hull~like configuration
for good mobility through the water, the tanks being arranged
catamaran~style as shown in Figure 1,
Each tank mounts on its upper su:rface a journal or
pillow block 66 so as to define a transverse axis therebetween.
Each block in turn mounts one end of a stub shaft 68 with the
opposite end of each stub shaft 68 being secured to a
cylindrical holding tank 70. The tank 70 is open at both ends
and has an upper portion 72 which projects above the water line
W and a lower portion 74 which extends below the water line.
The lower portion 74 is provided with an opening 76 the purpose
of which will be described hereinbelow.
The upper surface of each tank 64 is provided with
hand-rails 78 in a normal fashion and is also provided with :
a plurality of tie-up cleats 80.
The recovery unit 14 is connected to the collection
unit 12 for towing thereby by a catwalk unit 82. The catwalk
unit 82 includes a semicircular structure 84 covered by a screen
86 and is also provided with hand-rails 88. As seen in Figure
1 the structure 84 is elevated with respect to the flotation
tanks and a ladder 90 extends between the structure 84 and the
top of each flotation tank 64. The catwalk unit is pivotally
attached to the flotation tanks at the base of each ladder 90. :.
At the forward area of the structure 84 a tongue 92
is provided, the tongue being pivotally attached to the upper .~.
surface of the structure 84 as at 94, The tongue 92 is wide
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enough for a person to walk on and is provided with a handrail
96. At the forward end of the tongue 92 a downwardly extending
leg 98 fits within the well 38 and has the other half of the
ball-and-socket joint secured thereto for mating engagement
with the one half already provided at the base of the well 38.
Once the joint is secure,it is seen that the recovery unit 14
is connected to the collection unit 12 by the catwalk uni,t 82
and that a degree of freedom between the units 12 and 14 is
provided by the ball-and-socket joint and the other pivotal
connections~as between the tongue 92 and the structure 84, and ''
between the structure 84 and the flotation tanks 64.
Two further areas of adjustment on the recovery unit
are provided. FirSt of all,, a stabilizing cable 100 is,secured,
at one end to the bottom of the holding tank 70. The cable
passes over a pulley 102 mounted on the tongue 92 and has its
other end secured to a winch 104 mounted on a pedestal 106
atop one of the flotation tanks 64. This mechanism serves two
purposes: it maintains the holding tank 70 in a generally
, vertical orientation during towing and it permits a controlled ;
pivotting of the holding tank 70 on its stub shafts 68 whenever
such is desired.
.~ The second adjustment mechanism is provided by the
cable 108 which is anchored at one end to one of the flotation
- tanks 64, passes over a pair of pulleys 110 atop -the catwalk
; structure, and is anchored at the other end to a winch mounted
on a pedestal 114 on the other of the flotation tanks. With
this mechanism the catwalk unit 82 may be pivotally raised or
' lowered relative to the recovery unit 14.
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The pumping unit 16 will now be described with
particular reEerence to Figure 1 of the drawings. Below
the concentration area C of the collection unit 12 the slidable
sleeve 52 is secured to or may be integral with a generally
vertical conduit portion 116. Portion 116 continues the
sleeve 52 downwardly below the concentration area C and is,
of course, slidably vertically adjustable along with the sleeve
52. Contained within the conduit portion 116 is a plurality of
similar spiral vanes 118 affixed to the inside wall of the
conduit portion 116, which vanes impart a spiral or swirling
effect to any fluid passing thereby.
Below the conduit portion 116 is a pumping portion 120
which includes a generally 90 elbow portion 122. Within the
pumping portion 120 and between the vanes 118 and the elbow
portion 122 is a pump 124 having vanes 126 in the form of
propeller blades affixed to a shaft 1~8. The shaft is maintained
coaxial with the conduit and pumping portions 116 and 120 by
one or more shaft supports 130. Shaft 128 passes downwardly
through a sealed opening 132 in the elbow portion 122 and
terminates at a submergible drive motor 134. The motor 134
as well as the height of the sleeve 52 is control]ed by an
operator situated on the collection unit 12 and provided with
appropriate controls 136 mounted thereon. As the necessary
circuitry to achieve effective aontrol is well within the
expertise of a skilled person in the art it is not considered
necessary to discuss the details of such circuitry.
The elbow portion 122 feeds into a rectifier portion
138 which contains vertical and horizontally oriented vanes
140 and 142 respectively. From the rectifier portion 138 a
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first flexible conduit 144 extends to a sealable joint 146
to which is removably secured a second flexible conduit 148.
Conduit 148 extends between the collection unit 12 and the
recovery unit 14 and terminates at a second sealable joint 150.
Also secured to the second joint 150 is a third ]ength of
condui-t 152 which in turn sealably feeds into the opening 76
in the lower portion 74 of the holding tank 70. The conduit
152 is oriented relative to the holding tank 70 so that the
axis of the conduit 152, and of the conduits 144 and 148 as
well, is not aligned with the longitudinal centreline of the
units 12 and 14, and hence is not aligned with a radius of
the holding tank. This is for the purpose of imparting a
circular or spiral motion to fluid exiting from the conduit
~52 into the holding tank 70. This effect is further enhanced
by an outlet deflector cap 154 which may be secured to the
end of the conduit 152 within the holding tank 70, the cap 154
serving to deflect fluid Erom the conduit 152 towards the inner
wall of the holding tank 70.
OPERATION
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The operation of the present invention will now be
describedl with particular reference to Figure 1. For such
description it is assumed that the complete assembly has been
towed, floating on the surface of the water, to an oil spill
site by suitahle means, as by a tug boat, During such towing
; operation it is suggested that the length of conduit 148 be
disconnected at -the joints 146 and 150 to avoid damage and
that the holding tank 70 be winched up, as by cable 100, to a
generally horizontal attitude to improve the towability of the
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unit 14 and to avoid damage to the tank,
Once the spill site has been reached the holding
tank is lowered so as to assume its generally vertical orienta-
tion as shown in Figure 1 and the conduit 148 is connected at
the joints 146, 150. The collection unit i~; then towed into the
spill, connected to a containment boom towecl by suitable boats,
with the recovery unit being towed by the collection unit. An
oil/water mixture is funnelled by the walls 20 into the general
vicinity of the collection area C due to the forward movement
of the collection unit into the spill. The opening of the
sleeve 52 is maintained, under operator control, just below the
level of the oil floating on the water surface and the motor 134
is turned on. The motor drives the pump 124 so that an oil/water
mixture is drawn downwardly Erom above the sleeve 52 into the
sleeve past the spiral vanes 118. The spiral vanes induce a
degree of tuxbulence into the oil/water mixture, thereby tending
; to break up the oil from a continuous film or layer into smaller
particles which flow more easily past the pump 124 and through
the conduits 144, 148 and 152. The rectifier 138 smoothes out
the flow of oil/water mixture through the conduits and thus
permits some rejoining of the oil particles during the passage
through the conduits. The oil/water mixture flows through the
' conduits 144, 148 and 152 and is deflected by the deflector cap
154 into a flow pattern which is circular and essentially laminar,
following the inner wall of the holdiny tank 70. During such flow
within the tank the oil, having a lower specific gravity than the
water tends to rise to the surface of the water within the tank.
Uncontaminated water will eventually flow out through the open
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bottom end of the tank,
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The tank will eventually contain so much oil that
it will, in essence, be full. At that point in time a barge
or other vessel could be brought alongside the recovery unit
and the oil contained therein could be transferred by
conventional means to the barge for appropriate disposalO
As an alternative it would be possible to disconnect the full
recovery unit from the collection unit, as by disconnecting the
ball-and-socket joint and the conduit join~ 150 and to connect
an empty recovery unit to the collection unit. The full
recovery unit could then be towed to a shore installation for
disposal o~ the oil contained in the full holding tank thereof.
Of course, any other suitable method for disposing of oil in
the full holding tank could be utilized without departing from
the spirit of the present invention.
It is understood, of course, that a skilled person in
the art could alter the structure of the described apparatus
without departing from the splrlt of the present invention.
Accordingly the protection to be afforded the invention should
be determined from the claims appended hereto.
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