Note: Descriptions are shown in the official language in which they were submitted.
'` 10~>7709
This invention relates to apparatus and a method
for containing and gathering up material contaminating the
surface of a body of water. When oil or the like is spilled
into a harbour or other body of water, the most immediate
problem is to contain the oil so that it will not spread to
such an extent that it is not practical or worthwhile to
even try and remove the spillage. Sometimes a floating boom
is used in an attempt to stop the spread of water-borne
contaminants but the shear physical task of assembling a
lengthly boom as-is normally required, and of the maneuvering
- the boom into a position where it might be affective,
results in a delay which can render the whole exercise
futile. Furthermore, a boom can only be successfully em-
ployed when water conditions are ideal which seldom is the
case. Generally speaking, the present invention contemplates
the use of acoustical energy to provide, in effect, a huge
broom which can be wielded to sweep floating oil or the like
into a confined area from where it can more readily be
picked up by other means.
More specifically, apparatus according to the
present invention comprises a sound producing device having -
a member capable of transmitting a shaped and intensified
ray of vibrational energy, support means for supporting the
device with at least the member disposed below the water
surface in a position to direct the ray upwardly towards the
floating material at a selected grazing angle relative to
the water surface, and means for activating the sound
producing device to generate the ray and produce at the
water surface incidental to said ray reacting with air
thereabove a horizontally elongated and vertically flattened
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zone of vibrational energy capable of exerting a propelling
force on the floating material. ~ -
In drawings which illustrate preferred embodiments
of the invention,
Figure 1 is a schematic view showing one embodi~
ment of the present invention in a typical position of use,
Figure 2 is longitudinal and schematic section
showing apparatus of this embodiment taken on lines 2-2 of ,, '
Figure 1, ''-
Figure 3 is a schematic plan view of another "' '
embodiment of the present invention, '
Figure 4 is a vertical section taken on the line
4-4 of Figure 3, and
Figure 5 is a schematic side elevation of still '
another embodiment of the present invention.
Referring to Figure 1 of the drawings, there is
shown by way of example one use of the present invention. ~ ,
The,numeral 10 represents a river channel which is navigated ',
by ships 11 and the vessel illustrated in Figure 1 is assumed
to be moving upstream or against the river current. An oil
spill in such a river channel presents a major clean up
problem since it spreads so quickly but downstream movement ,~
of oil or other contaminating materials such as wood chips ~
and the like, can be halted by use of the present invention ;' ~ ',
a number of which may be arranged as shown schematically in ';~ ,, ',
Figure 1. '';
The numeral 20 indicated generally a sonic sweeping
apparatus a suitable number of which are shown in Figure 1 ' '
supported below the water surface by means generally indic- '
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ated at 22. The support means 22 for this embodiment is an
anchor assembly formed of cables 23 and 24, the ends of the
latter cables being suitably anchored as at 25 on land
bordering the channel. Anchor cables 26 hold the cables 23,
and therefor the apparatuses 20, a suitable distance below
surface 28 of the channel so that ships and floating debris
can pass without inteference.
Referring now to schematic Figure 2, each apparatus
20 is shown to comprise a hollow vessel 30 which is provided
with laterally projecting lugs 31 to which the cables 23 are
attached. The vessel 30, which has a plastic dome 32, is
supported by the cables with the dome facing upstream.
Horizontal stabilizers 33 are provided on the hollow vessel,
the stabilizers each being disposed at a slight angle to the
horizontal axis of the vessel so that the river current acts
to hold the apparatus tilted upwardly. Preferably, the
vessel 30 is filled with silicone oil which has not been
indicated or enumerated in the schematic Figure 2.
Suitably mounted within the vessel 30 is a sound
producing device 36 which comprises a body 37 and a member
38 capable of transmitting vibrational energy to a fluid
medium such as water. Preferably, the member 38 used in
this embodiment of the invention is a transducer consisting
of a polarized ceramic dish having a concave face 39 from
which acoustical waves are emitted when the ceramic material
is energized electrically. For this purpose, a suitable
electric circuit 40 connects the member or transducer 38 to
a source of high frequency alternating current (not shown)
on land near the channel 10, some of the wires of the
circuit being carried by the cables 23. Thus, the focused
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transducer 38 can be energized to produce vibratory waves
which are directed forwardly of the vessel 30 through the
dome 32. These waves are concentrated or shaped as well as
intensified by the transducer to form a ray of acoustical
energy. The wave frequency may be in either the sonic or
ultrasonic range.
Transducer 38 is mounted within the vessel 30 by
means generally indicated at 43. This mounting means 43
includes a V-shaped yoke 45 which carries opposing pivot
pins 46, the device 36 being supported by the pins to rock
about the transverse and substantially horizontal axis of
the pins. The yoke 45 can swing about the vertically dis-
posed axis of a pivot pin 47 which secures the yoke to a
suitable part within the hollow vessel.
lS A drive mechanism generally indicated at 50
serves to rock the device 36 about the horizontal and
vertical axis of the pins 46 and 47. The mechanism 50 is
shown to comprise an electric motor 52 which drives a shaft
53 through a reduction (not shown), the shaft being fitted
with a pinion 54. A self-contained displacement pump 55 is
positioned alongside the shaft 53 and a driven shaft 56 of
this pump carries a gear 57 which meshes with the pinion
54. The outlet from the pump 55 is connected by a conduit
59 to a cylinder 60 fitted with the piston 61 having a rod
62. A pin 64 pivotally connects the piston rod to one end
of crank 65 which has its opposite end (not shown) suitably
secured to the body 37. Both pivot pins 46 are fitted with
springs 67 which bias the device 36 so that normally the
piston 61 is urged towards the conduit end of the cylinder
60.
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The mechanism 50 also includes separate a drive
train between the electric motor and the member 45. This
train comprises a worm 70 which is fitted to the shaft 53.
A gear 72 is rotatably mounted on an interior part of the
vessel 30 to engage this worm. Worm gear 72 is fitted with
a crank 73. The member 45 and the crank 73 are pivotally
connected together by a rod 74 and pins 75.
The motor 52 is connected into an electric circuit
76 which extends out of the hollow vessel 30 and along the
cables 23 to a suitable source of low frequency electric
power on land. Thus, the motor 52 can be driven while high
frequency current is delivered separately to the transducer
38. Rotation of the electric motor 52 causes similar move-
ment of the pump 55 whereby pulsating hydraulic pressure is
delivered to the cylinder 60. This causes the piston rod 62to extend against the pressure applied by the springs 67 and
later to retract under spring pressure. The transducer 38,
as a result, is rocked about the horizontal axis of the
pivot pins 46. At the same time, rotation of the shaft 53
results in the transducer 38 being swung back and forth
about the pivot pin 47.
In operation, the device 36 is electrically
energized so that the transducer 38 produces acoustical
waves. Frequencies below ultrasonic are preferred since
there is less attenuation when travelling through water.
The upwardly as a ray which reaches waves diverge from the
centre of the transducer as a ray which reaches the surface
of the water at a collective angle of incidence relative to
the water surface, which angle is commonly referred to as
the grazing angle. At the surface, the acoustic waves
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encounter the air above the water surface and the air, of
course, has an impedance factor much greater than that of
water. This results in a zone of vibrational energy being
developed which is directed forwardly to act upon the
contaminating layer of oil which then becomes a sound
channel or wave guide for the energy. The zone is very
narrow vertically, or not much thicker than the oil layer
itself. On the other hand, the zone is greatly elongated
horizontally due to the normal propagation of the sound -
waves and the fact that the vibrational energy is trapped
between the air and water surfaces. This creates a thin and
fanned-out zone of vibrational energy which is largely
confined to the oil layer and is further intensified as a
result of being flattened so as to serve as a horizontally
directed propelling force. The resultant force is applied
in such a way that the zone of vibrational energy becomes a
sonic or dynamic barrier for the oil or other contaminating
substances. The oil being carried downstream encounters :;
this sonic barrier which extends from bank-to- bank between
the several apparatuses 20 and, as a result, is brought to a
halt. In other words, a sweeping action results since the
water continuous its downstream flow.
The oil starts to accumulate at the sonic barrier
almost as if it had encountered a solid boom and eventually
this steadily increasing accumulation must be removed as
well be explained latter.
If the water surface is quite smooth, the sonic
sweeping apparatus 20 will operate effectively as described
above without the transducer being oscillated within the
vessel 30. The water surface, however, is often roughened
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by the wind and the action of passing boats so that it is
best if the transducer 38 is oscillated about the horizontal
axis provided by the pins 46. The motor 52 is run contin-
ously when the water is rough and, through the mechanism S0,
the sound producing device is caused to rock back and forth ;;
on the pins 46 whereby to continuously vary the grazing
angle. This rocking motion provides the sonic barrier with
a fore and aft sweeping action simulating that of a broom
being used on a floor. As a result, the oil is brushed or
stroked along the water surface which helps to sweep up or
provide a herding action with regard to any small patches of
oil which might otherwise escape past the sonic barrier
because of the roughened surface of the water.
The transducer 38 is also oscillated about the
axis provided by the pivot pin 47 and this provides a hori-
zontal sweeping action which further improves the effective-
ness of the sonic barrier. The sideways sweep imparted to
the barrier also helps to gather up stray patches of oil and
add then to the accumulation. In addition, the horizontal
sweeping action increases the effective width of the zone of
vibration energy provided by each sonic sweeping apparatus
.
20 so that fewer such devices need by used in the arrange-
ment shown in Figure 1.
;~ Preferably, the oil accumulated at the sound
~; 25 barrier is picked up by the method and apparatus for ultra-
sonically removing contaminants from water as described in
United States Patent No. 4,032,438 which was granted on June
28, 1977 to this applicant.
There are other pieces of equipment which can be
used to remove the oil gathered at the sonic barrier and one
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is a conventional weir-type oil skimmer which executes a
skimming action as the name implies. Other equipment
presently available will slurp the oil up off the water
surface but both the oil skimmer and the oil slurp are
effective only when the contaminating material is concen-
trated within a relatively small area as accomplished by use
of the present invention.
The sonic sweeping apparatus 20 has been described
as being equipped with an electrically energized transducer
but it will be noted that other sources of vibrational
energy might be employed as well. For example, a hydro-
dynamic oscillator of conventional design has a sound
producing transducer and associated parts which prod~ce the
sound waves required for a sonic barrier used to sweep ~ ;
contaminating material floating on the surface of a body of
water. An array of transducers may be carried by the
support means 22 so as to collectively provide the zone of
vibrational energy. The transducers need not be dished but
can be flat and associated with lenses wave guides, re-
flectors and the like to concentrate or intensify theacoustic waves. Some horns which have a diaphragm or
transducer operated by fluid pressure will also serve the
intended purpose. Only the wave emitting member of the
sound producing device need be submerged below the surface
of the water.
Figure 3 and 4 illustrate another embodiment of
the present invention. In this instance, an array of three
sound producing devices 80 are used. These devices are
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construc~ed as previously described and are supported by
means generally indicated at 82 and comprising a surface
vessel 83 fitted with a forwardly-projecting boom 84. The
devices are suitably mounted on the forward end of the boom
and a mounting means 85 secures the opposite end of the boom
to the bow of the boat. The vessel 83 is self propelled and
has the usual steering apparatus and so on as will the
sources of power for operating the devices 80 and the boom
84.
Referring now to Figure 4 the mounting means
generally indicated at 85 will be seen to comprise an annular
base 90 which is mounted on the boat 83 concentric with a
vertical opening 91 extending through the hull at the bow.
Blocks 92 mounted on this base carry opposing spindles 93 on
which a housing 94 is rockingly mounted. A shaft 95 is
journalled in the housing to depend through the opening 91
and the opposite or inner end of the boom 84 is fixedly
secured to the lowermost end of the shaft. This arrangement
allows the boom and therefore the sound producing devices to
be swung about the horizontal axis provided by the spindles
93 and the vertical axis provided by the shaft 95.
The housing 94 encloses a drive mechanism generally
indicated at 97 for oscillating the boom 84 and therefore
the devices 80 about the aforementioned horizontal and
vertical axes. Mechanism 97 comprises a motor 98 which
drives a shaft 99 through a magnetic clutch 100. A worm 101
on the shaft 99 meshes with a gear 102 non-rotatably secured 7
to one of the spindles 93. Motor 98 is included in a circuit
103 (Figure 4 only) leading to a source of power (not shown)
aboard the boat and controlled by the boat operator. When
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the motor 98 is energized, the boom 84 is oscillated at a
suitably slow speed in a substantially vertical plane and
the extent of swing is determined by limit switch means ;~
105.
The drive mechanism 97 includes another electric -~
motor 110 mounted within the housing drives a shaft 111
through a magnetic clutch 112. This shaft 111 carries a
worm 114 engaging a gear 115 which is secured to the shaft
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95. Motor 110 has a circuit 117 (Figure 4) connecting it to
a source of power (not shown) aboard the surface vessel 83.
The boom 84 is slowly oscillated about the axis of the shaft
95 when the motor 110 is run and the extent of swing is
controlled by other limit switch means 118, see Figure 4.
The sound producing devices 80 are included in a
lS circuit 120 part of which is carried within the boom 84 to
the bore of the shaft 95. From the shaft 95, the circuit
120 extends out the top of the housing 94 thence to a A.C.
motor generator 121 carried aboard the boat 83. The boat
operator, of course, can control the power to the devices 80
- 20 as well as to the motors 98 and 110.
The embodiment of the invention shown in Figures 3
and 4 is particularly well suited for sweeping up an oil
spill in a harbor or elsewhere. For this purpose, the -
vessel 83 is moved slowly forward with the devices 80 acti-
vated and angled upwardly to ensure an appropriate grazing
angle. The acoustic waves reach the water surface and react
with the air to provide a horizontally elongated and vertically
flattened zone of vibrational energy which propels the oil
ahead of the boat. The devices 80 are oscillated when
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required by swinging the boom up and down as well as from
side to side so that a thorough sweeping action is assured.
The boat 83 is maneuvered around the oil spill to gather the
contaminating material into a pool which can be picked up by
one of the collectors previously described. For example,
the oil can be herded directly into a weir-type oil skimmer.
Figure 5 shows still another embodiment of the
invention wherein a submersible vessel 130 is used to perform
the sweeping operation. Vessel 130 carries a boom 132 on
which an array of sound producing devices 133 are mounted. The
boom 132 is attached to the submarine by mounting means 134
which is the same as the means 85 except that it is inverted
on the vessel. Otherwise the construction of this embodiment
of the invention is similar to the previously described
lS embodiment and therefore further detailed description is not
considered necessary.
The invention shown in Figure 5 operates in the
same manner as the embodiment shown in Figure 3 and 4 except,
of course, that the vessel 130 is submerged along with the `
boom 132 and the sound producing devices 133. Use of the
submarine will allow an accumulation of oil to be swept up
from the surface of a body of water or even from beneath a
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layer of ice as illustrated in Figure 5.
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