U.S. patent application number 14/480408 was filed with the patent office on 2015-04-30 for light weight oriented net assembly for oil capture and containment.
This patent application is currently assigned to TENSAR CORPORATION. The applicant listed for this patent is TENSAR CORPORATION. Invention is credited to Brian Edward CONNELLY, Daniel Charles HABICHT, Matthew David STEWART.
Application Number | 20150114909 14/480408 |
Document ID | / |
Family ID | 45805631 |
Filed Date | 2015-04-30 |
United States Patent
Application |
20150114909 |
Kind Code |
A1 |
STEWART; Matthew David ; et
al. |
April 30, 2015 |
LIGHT WEIGHT ORIENTED NET ASSEMBLY FOR OIL CAPTURE AND
CONTAINMENT
Abstract
A light weight oriented net or netting assembly is provided for
oil capture and containment. The netting assembly is made by
biaxially stretching or orienting starting materials to form a
pattern of oriented strands and integral junctions that, while
being light in weight, is also strong enough to be used to capture
and remove oil from contaminated water without an outer stabilizing
jacket. The assembly is preferably made from oriented polypropylene
netting that is folded, gathered, bunched and/or otherwise layered
upon itself on the order of 16-64 times and then crimped in one or
more locations to secure the netting layers in a bow tie or tubular
configuration that forms net cavities and an open cell structure to
capture and contain oil that has been dispersed in water. Oil in
the netting assembly can then be removed, such as by pressing or
other removal process, after which the netting assembly may be
reused.
Inventors: |
STEWART; Matthew David;
(Sharpsburg, GA) ; CONNELLY; Brian Edward;
(McDonough, GA) ; HABICHT; Daniel Charles;
(Peachtree City, GA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
TENSAR CORPORATION |
Alpharetta |
GA |
US |
|
|
Assignee: |
TENSAR CORPORATION
Alpharetta
GA
|
Family ID: |
45805631 |
Appl. No.: |
14/480408 |
Filed: |
September 8, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
13204130 |
Aug 5, 2011 |
8828236 |
|
|
14480408 |
|
|
|
|
61344487 |
Aug 5, 2010 |
|
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Current U.S.
Class: |
210/671 ;
210/488; 210/693; 493/394 |
Current CPC
Class: |
B01J 20/261 20130101;
E02B 15/101 20130101; B01J 20/28014 20130101; Y10T 29/49826
20150115; C02F 2101/32 20130101; B65H 45/12 20130101; E02B 15/10
20130101; C02F 1/681 20130101; C02F 1/285 20130101; Y02A 20/204
20180101 |
Class at
Publication: |
210/671 ;
210/488; 210/693; 493/394 |
International
Class: |
E02B 15/10 20060101
E02B015/10; B65H 45/12 20060101 B65H045/12 |
Claims
1-16. (canceled)
17. An oil capture and containment net comprising a plurality of
layers of netting made of an oil adsorbing polymer, said layers
being secured in a bundled arrangement with at least one crimping
element in at least one location of said netting, said crimping
element forming irregular channels in said netting for increased
surface area of said net for better capture and containment of oil
dispersed in water.
18. The oil capture and containment net as set forth in claim 17,
wherein said crimping element secures the netting in a generally
bow tie configuration.
19. The oil capture and containment assembly as set forth in claim
18, wherein said bow tie configuration includes net cavities and an
open cell structure forming said irregular channels.
20. The oil capture and containment net as set forth in claim 17,
further comprising a plurality of crimping elements spaced from one
another lengthwise along the netting.
21. The oil capture and containment net as set forth in claim 20,
wherein said plurality of crimping elements includes a crimping
element adjacent each end of the netting to form a tubular
configuration for said net.
22. The oil capture and containment assembly as set forth in claim
17, wherein said netting is light weight oriented netting.
23. The oil capture and containment assembly as set forth in claim
17, wherein said oil adsorbing polymer is polypropylene.
24. The oil capture and containment assembly as set forth in claim
17, further comprising a handling and connection element.
25. The oil capture and containment assembly as set forth in claim
24, wherein said handling and connection element includes a
rope.
26. The oil capture and containment assembly as set forth in claim
25, wherein the rope has a plurality of knots in a lengthwise
center of the rope.
27. The oil capture and containment assembly as set forth in claim
25, wherein the rope has a loop tied at each end and a fastener at
one end by which the assembly can be attached to another oil
capture and containment assembly.
28. A method of manufacturing an oil capture and containment
assembly comprising the steps of: bundling a length of netting to
have a plurality of layers; and securing the bundled layers
widthwise with at least one crimping element in at least one
location of said netting to form irregular channels or openings
through the bundled layers that increase an overall surface area of
said netting for better capture and containment of oil dispersed in
water.
29. The method as set forth in claim 28, wherein said step of
bundling includes folding, rolling or bunching the netting to
create at least sixteen layers of said netting.
30. The method as set forth in claim 28, wherein said crimping
element secures the netting in a generally bow tie
configuration.
31. The method as set forth in claim 28, wherein said step of
securing the layers includes securing the layers of netting with a
crimping element in at least two locations spaced from one another
along said length, the crimping elements forming irregular channels
through the assembly for increased surface area and better
retention of captured oil when the assembly is removed from
oil-contaminated water.
32. The method as set forth in claim 31, wherein said crimping
elements secure the netting in a tubular configuration that
includes net cavities and an open cell structure.
33. A method of capturing and containing oil dispersed in water
comprising: forming an oil capture and containment assembly having
a plurality of layers of netting made of an oil adsorbing polymer,
said layers being bunched together and secured widthwise with at
least one crimping element in at least one location along a length
of said netting; placing the assembly into water contaminated with
oil, said assembly adsorbing a quantity of said oil through contact
between said assembly and the oil.
34. The method as set forth in claim 33, further comprising the
steps of: removing the assembly with the quantity of adsorbed oil
from the water; reclaiming said adsorbed oil from said assembly;
and reusing said assembly to capture and contain more oil.
35. The method as set forth in claim 33, further comprising the
steps of: fastening the oil capture and containment assembly to
another oil capture and containment assembly end to end to create a
string of oil capture and containment assemblies.
Description
[0001] This application is a continuation application of U.S.
patent application Ser. No. 13/204,130, filed Aug. 5, 2011, issuing
as U.S. Pat. No. 8,828,236 on Sep. 9, 2014, which claims priority
of U.S. provisional application Ser. No. 61/344,487 filed Aug. 5,
2010, the priority of which is hereby claimed.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention is related to the field of oil
adsorption and, more particularly, to an assembly for capturing and
containing oil that has been released into water.
[0004] 2. Description of the Related Art
[0005] Polypropylene is used in the oil adsorption industry for its
inherent affinity for capturing and containing oil. One common
configuration is a "sock" design in which a quantity of
polypropylene pellets or pieces are placed within an outer shell or
jacket that provides structural integrity and is permeable to oil.
In use, the oil flows through the jacket or sock and adheres to the
polypropylene particles for containment in the sock. Absorption
media can also be placed within an outer jacket to capture oil, and
these media include corn husks and cotton fibers which are disposed
of after a single use. With both adsorption and absorption
materials as used according to the prior art, the quantity of
refuse to be disposed of can accumulate quickly in the event of a
large oil spill. With typical disposal methods including
incineration and/or landfill deposit, disposal can become
burdensome, costs can be high, and the environment is negatively
impacted.
[0006] A further disadvantage of the sock configuration is that the
sock has a defined shape and size depending on the outer jacket or
shell used to contain the adsorbent or absorbent material. Hence,
the polypropylene or other adsorbent material cannot expand or
contract with the water current or wave action.
SUMMARY OF THE INVENTION
[0007] In view of the foregoing, the present invention is directed
to a light weight oriented net or netting assembly having a series
of irregular or regular openings that is preferably made of
polypropylene having a natural affinity for oil. For the purpose of
this invention, the terms "light weight oriented net" or "light
weight oriented netting" and "oriented net" or "oriented netting"
are intended to mean integral oriented net or netting made by
biaxially orienting (stretching) polymeric sheet-like starting
material to form a pattern of oriented strands integrally
interconnected by partially oriented junctions. The terms "net" and
"netting" and "oriented net" and "oriented netting" are used
interchangeably throughout this application. By using oriented
nets, the resulting oriented net assembly, while being light in
weight, is also strong enough to make an outside containment and
stabilizing jacket unnecessary.
[0008] To form the desired assembly, light weight oriented net or
netting, preferably made of polypropylene, is folded and/or layered
upon itself until the desired number of layers have been created.
The polypropylene netting layers are then gathered, bundled or
otherwise drawn together at one or more points along their layered
length and crimped to secure the netting layers into a bundled or
gathered assembly. According to a preferred embodiment, the folded
or otherwise gathered netting layers are crimped in about the
center to form a "bow tie" configuration. The bow tie netting
assembly can also be crimped near each of its ends and may also be
crimped in additional intermediate locations, if desired.
Alternatively, the gathered netting layers may be crimped near end
portions thereof but not in the center to form a tubular
configuration. As used herein, when features and performance of the
"bow tie" netting assembly are described, it is understood that the
same features and performance apply to the tubular configuration as
well.
[0009] The layers of oriented netting are buoyant and have a
specific gravity to remain adjacent the contaminated water surface.
When layered between 16 and 64 times, the bow tie netting assembly
initially captures and contains a quantity of oil approximately 20
to 25 times the initial weight of the netting. Oil in the netting
can then be removed, such as by pressing, after which the assembly
may be reused. During multiple re-uses, the oriented netting
assembly effectively captures and contains a quantity of oil
approximately 15 to 16 times its weight during each use. The
reduced yield obtained during subsequent reuses is due to the
polypropylene netting having a reduced affinity for oil due to oil
residue that remains on the netting after the bulk of the oil has
been removed.
[0010] In view of the foregoing, one object of the present
invention is to overcome the drawbacks in conventional sock designs
in which the sock media can only be used once.
[0011] Another object of the present invention is to provide an
adsorbent medium in the form of a light weight, oriented net or
netting assembly preferably made of polypropylene for capturing and
containing oil that can be used and reused many times.
[0012] Yet another object of the present invention is to provide an
oriented net or netting assembly in accordance with the preceding
object that, due to the biaxially oriented strands interconnected
by integral, partially oriented junctions, has sufficient strength
within its own structure to maintain the integrity of the assembly
when burdened with oil in use so as to eliminate the need for an
outer jacket.
[0013] A further object of the present invention is to provide an
oriented net assembly in accordance with the preceding objects that
effectively attracts oil in water so that the oil can be removed
from the water and then, by subjecting the oriented net assembly to
a pressing or other removal process, releases the captured oil so
that such oil can be refined and used.
[0014] A still further object of the present invention is to
provide an oriented net assembly in accordance with the preceding
objects that can be repeatedly reused and, when reused, is able to
capture and contain a quantity of oil up to approximately 15 to 16
times its own weight during each use.
[0015] Another object of the present invention is to provide an oil
capture and containment assembly in accordance with the preceding
objects that is not complex in structure and which can be
manufactured at low cost but yet efficiently captures many times
its own weight in oil that has been dispersed in water.
[0016] Yet another object of the present invention is to provide an
oil capture and containment assembly in accordance with the
preceding objects that is environmentally friendly.
[0017] These together with other objects and advantages which will
become subsequently apparent reside in the details of construction
and operation as more fully hereinafter described and claimed,
reference being had to the accompanying drawings forming a part
hereof, wherein like numerals refer to like parts throughout.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] FIG. 1 is a photograph of a light weight oriented net
assembly for oil capture and containment having a single central
crimp in accordance with the present invention.
[0019] FIG. 2 is a photograph of a light weight oriented net
assembly for oil capture and containment having a single central
crimp as in FIG. 1, and also including a handling and connection
element in accordance with the present invention.
[0020] FIG. 3 is a photograph of another light weight oriented net
assembly for oil capture and containment having end crimps
according to the present invention.
[0021] FIG. 4 is a photograph of a much larger light weight
oriented net assembly for oil capture and containment having
central and end crimps according to the present invention.
[0022] FIG. 5 is a sketch of a roll of oriented polypropylene
netting with a length unrolled for forming a light weight oriented
net assembly for oil capture and containment in accordance with the
present invention.
[0023] FIG. 6 is a sketch of the roll shown in FIG. 5 having been
unrolled and folded to form three layers which will be crimped to
form a light weight oriented net assembly for oil capture and
containment in accordance with the present invention.
[0024] FIG. 7 is a drawing of a representative fabrication set-up
for converting light weight oriented polypropylene netting rolls
into oil capture and containment assemblies through the layering
procedure illustrated in FIG. 6.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0025] In describing a preferred embodiment of the invention
illustrated in the drawings, specific terminology will be resorted
to for the sake of clarity. However, the invention is not intended
to be limited to the specific terms so selected, and it is to be
understood that each specific term includes all technical
equivalents which operate in a similar manner to accomplish a
similar purpose.
[0026] As shown in FIGS. 1-4, the present invention is directed to
a light weight oriented net or netting assembly for oil capture and
containment generally designated by reference numeral 10. The light
weight oriented net or netting assembly 10 is preferably made of
polypropylene netting or net material 12 that is plied, rolled,
spiraled, folded, gathered or bunched in a manner as to create
multiple layers. When the desired number of layers has been
achieved, the stack of layers is gathered or bundled widthwise and
secured with a crimp element 14 that is located at approximately
the center of the layered netting material 12 in the lengthwise
direction. The oriented netting assembly may alternatively be
crimped with end crimps 16, 18 near each end 20, 22, while the
center is not crimped as shown in FIG. 3. The layered netting or
net material 12 may also be crimped with both end crimps 16, 18
near each end 20, 22 and a central crimp element 14 as shown in
FIG. 4.
[0027] As shown in FIGS. 1-4, the result of crimping in accordance
with the present invention is to create a "bow tie" or tubular
configuration in which the width of the layered netting where the
layers have been gathered together is secured while allowing for a
significant amount of the surface area of the netting to be exposed
between the crimps during use.
[0028] In particular, by crimping the multiple layers of netting,
net cavities 24 are created on each side of the crimp(s). These net
cavities 24 form an open cell structure for the net assembly 10 in
order to maximize the surface area of the netting layers for better
capture and containment of the oil. The net cavities 24 thus allow
for greater oil retention both while the oriented netting assembly
is in service and as the netting assembly is being removed from the
water as will be discussed more fully hereinafter. The crimps 14,
16, 18 are preferably made using zip ties, although other crimp
elements as well as any number of crimping or tying methods may
also be used to create the bow tie configuration as would be
understood by persons of skill in the art.
[0029] Moreover, the spacing of the crimps allows the oriented
netting forming the net cavities 24 to expand and contract in the
length and width directions as the crimps move closer or further
apart, respectively, under the influence of water flow or current.
Also, the "free" end portions of the net positioned outside the
outermost crimps and forming the ends of the crimped assembly are
free to expand and contract as influenced by water movement. As a
result, the netting assembly according to the present invention
does not have a fixed width or length during use, enabling the
assembly to adapt to the water conditions in which it is placed
during use.
[0030] As shown in FIG. 2, the bow tie configuration of the
oriented netting assembly may include a handling and connection
element 23. In the embodiment shown, the handling and connection
element 23 is a rope, but other materials or components could also
be used as would be understood by persons skilled in the art.
However embodied, the handling and connection element 23 provides a
"handle" to assist in installation and removal of the net assembly
from an oil capture site. Also, as would be understood, the tubular
configuration shown in FIG. 4 may be similarly equipped with a
handle element 23.
[0031] When configured as a rope, the handling and connection
element 23 is preferably provided with a series of knots 26 in the
lengthwise center of the rope. The knots catch on the crimp 14 and
prevent the rope from pulling out of the oriented netting assembly
10 when the rope is used to move the assembly. In addition, the
rope 23 may be provided with a loop 28 tied at each end and a
fastener 30 at one of the ends by which the bow tie configuration
of the oriented netting assembly can be attached to another similar
netting assembly to create a string of connected assemblies for use
in large oil recovery situations.
[0032] As can be seen in FIGS. 1 and 2, and as best shown by the
partially sketched strands in FIGS. 5 and 6, the netting 12
includes a plurality of lengthwise oriented strands 34 and
widthwise oriented strands 36 formed by orienting, or stretching,
the netting or net material 12 during manufacture. Orienting of the
netting or net material 12 is performed according to conventional
processes as is known in the art of net and netting manufacture. In
this regard, light weight biaxial nets have been manufactured for
many years primarily from a tubular cast extrusion process, and are
used in many applications including carpet backing, erosion
control, filtration support, etc. Such nets may be integrally cast
and then stretched using any of a variety of well known techniques
such as those described, for example, in U.S. Pat. No. 2,919,467 to
Mercer; U.S. Pat. No. 3,070,840 to Mercer; U.S. Pat. No. 3,252,181
to Hureau; U.S. Pat. No. 3,317,951 to Hureau; U.S. Pat. No.
3,384,530 to Mercer et al.; U.S. Pat. No. 3,384,692 to Galt et al.;
U.S. Pat. No. 3,496,965 to Hureau; U.S. Pat. No. 3,917,889 to
Gaffney et al.; and U.S. Pat. No. 4,756,946 to Mercer. The subject
matters of all of the foregoing identified nine patents are
expressly incorporated by reference in this application as if set
forth fully herein. These patents are cited as illustrative, and
are not considered to be all inclusive, or to exclude other
techniques known in the art for the production of oriented
nets.
[0033] Once oriented, the netting has integral strands and
junctions that are strong enough to maintain the integrity of the
netting assembly both during use and while being drawn out of
contaminated water after having adsorbed a large quantity of oil.
The oriented net or netting according to the present invention
typically has mesh openings or apertures 38 defined by the crossing
strands that are generally square with each side preferably
measuring between about 0.20 inches and about 1.5 inches. However,
the net or netting structure is not limited to generally square
apertures nor to regular openings, but can include a wide range of
regular and/or irregular openings arranged in a generally
consistent pattern or in an irregular pattern that create an open
structure having a large surface area for oil adherence capture. In
this regard, oriented net or netting that falls short of product
specifications for use in a given industry may still be effectively
used as an oil capture and containment assembly in accordance with
the present invention, with a resulting reduction in manufacturing
waste.
[0034] In addition, the openings in the netting, whether regular or
irregular in themselves, form irregular channels or openings
through the assembly once the layers are crimped, due to the
bunching and gathering of the layers. As a result, while the
assembly has an open cell structure that maximizes the surface area
to which the oil can adhere, both the bow tie and the tubular
configurations create an irregularity in the passages through the
assembly that are otherwise created by the apertures in the
oriented netting. So unlike a flat net in which the openings are
regular and extend entirely through the assembly so that a straight
object like a rod can be pushed through the structure's openings
from one side of the net to the other, the bow tie and tubular
configurations force the openings in various layers out of
alignment such that a straight object cannot be easily threaded
through the assembly. As a result, the net assembly according to
the present invention has an improved ability to retain oil adhered
thereto when the net assembly is removed from the water.
[0035] The light weight oriented netting 12 is typically made in a
roll 40 as shown in FIGS. 5 and 6, or may be made according to
other conventionally known methods of polymer netting manufacture.
The light weight netting 12 is made of a polymer, preferably
polypropylene, that has an inherent affinity for oil. Preferably,
the polymer has a melt index range of between about 0.5 g/10 mins
and about 4.0 g/10 mins. Other polymers may also be used, such as a
polyethylene polymer, provided the polymer chosen has an affinity
for oil. The netting or net material may be made in various colors
ranging from green and black to clear.
[0036] Depending upon the thickness of the strands, the weight of
the netting 12 per square foot will vary. A preferred weight range
for polypropylene netting in accordance with the present invention
is between about 0.75 lb/1,000 sq. ft. and about 30 lb/1,000 sq.
ft. With netting weights within this range, the resulting oil
capture and containment assemblies 10 made from this material are
light in weight, buoyant so as to remain adjacent the water
surface, and yet, due to their oriented structure and integrally
formed strands and junctions, are strong enough to make an outside
containment and stabilizing jacket unnecessary during use of the
netting assemblies to capture and remove oil from contaminated
water. By eliminating the outer jacket, the total oil-exposed
surface area of the polypropylene netting is effectively increased,
thereby increasing oil capture and containment capability for a
given weight and surface area of the oriented netting.
[0037] As illustrated in FIG. 6, according to one method of
manufacture, the roll 40 of oriented netting is unrolled to a
desired length and then folded, gathered, bunched and/or laid down
upon itself until the desired number of layers has been reached.
Three layers are shown at the stage of production shown in FIG. 6,
but it is preferred to have the oriented netting layered between
about 16 and 64 times to form one of the bow tie configuration
assemblies. Using the roll method of manufacture, the oriented
netting assemblies can be made to any desired length, with netting
assemblies up to 100 feet long or more being possible. With longer
netting assemblies, more crimps may be used, effectively creating
more oil retaining pockets 24 between the crimps. However, the
crimps should be spaced well apart to multiply the amount of
netting that is exposed over a given length. Preferably the crimps
are at least five feet apart to allow for spreading of the netting
and to maximize the netting surface area and resulting oil capture
and containment. The width of the net is limited by the
manufacturing equipment used to make the rolls, with the width of
the roll generally being between about 23 inches to a maximum of
about 250 inches.
[0038] A representative fabrication set-up for converting light
weight oriented netting rolls into oil capture and containment
assemblies through the layering procedure is illustrated in FIG. 7
and generally designated by reference numeral 50. Other fabrication
set-ups may also be used. According to the manufacturing embodiment
shown in FIG. 7, the fabrication set-up 50 includes at least one
layout table 52 upon which the oriented netting is unrolled to a
desired length. Additional layout tables, such as the two tables
52, 54 shown in FIG. 7, may be placed side by side to support a
longer netting assembly. Positioned over and on either side of the
tables is a horizontal bar 56, 58 supported by steel support beams
60. The bars 56, 58 may be used to support the two opposite ends of
a rod 62 that is passed through the center of the roll 40 to allow
the roll to be unrolled while supported by the rod 62. By sliding
the rod 62 along the bars 56, 58 back and forth over a distance
corresponding with the length of the layout tables 52, 54 below
while unrolling the roll 40, multiple layers of the netting 12 can
be laid down, one upon the other, and supported upon the tables to
form a netting assembly 10.
[0039] In addition to the bow tie and tubular configurations, oil
capture and containment netting assemblies according to the present
invention may be made in a layered pillow configuration, similar to
that used in prior art products. In the layered pillow
configuration, netting in accordance with the product
specifications already summarized above is layered and fitted
within an outer casing of the same material.
[0040] In a further configuration, multiple layers of oriented
netting are sewn together along one side edge of the stacked,
bundled or otherwise gathered layers to create an assembly that
resembles a book. Test results of the effectiveness of oil capture
and containment oriented netting assemblies in the book
configuration are summarized by the first trial as set forth in the
Table I below.
TABLE-US-00001 TABLE I First Trial Effectiveness Testing of
"Pillow" versus stretched net Weight of Weight of Pad Weight of
Weight gain Water and Oil before Material after of material Weight
of lb. captured/lb Test # Description (lb.) introduction (lb.)
introduction (lb.) (lb.)* Poll after test of polypro 1 Stretched
1.1 lb 142.5 0.40 1.42 1.02 141.0 2.55 net inside single 1.1 lb
cast pillow 2 Fluff inside single 141 1.70 2.86 1.16 139.5 0.68 1.1
lb cast pillow 3 Fluff inside 139.5 0.96 1.84 0.88 139.0 0.92
double 1.1 lb cast pillow 4 Stretched net 139 139 1.06 0.96 138.0
9.60 3.7 C sewn together on one side "Book" 8 Layers *This includes
any trapped water Independent Variables Oil Added to Pool (lb) 1.8
Water in Pool (lb) 140 % Oil in water 1.3%
[0041] During the first trial, the book configuration of the oil
capture and containment netting assembly (Test #4) was tested
against three prior art products including a stretched net inside a
single cast pillow (Test #1), fluff inside a single cast pillow
(Test #2), and fluff inside a double cast pillow (Test #3). For
each test, 1.8 pounds of oil was poured into 140 pounds of water
contained in a molded backyard pool of the kind used by small
children.
[0042] The book configuration according to the present invention
was made with oriented clear (C) polypropylene netting having a
weight of 3.7 lbs/1,000 sq. ft. A specification sheet for this
commercially available netting is set forth below in Table II.
TABLE-US-00002 TABLE II Product LW037C Structure Type Light
Weight-Oriented Polymer Type Polypropylene Color Clear/Natural Unit
Weight 3.7 lb./M Ft.sup.2 MD & TD Mesh Size 0.25'' .times.
0.25'' Target MD & TD Tensile Strength 28.0/23.0 MD/TD min.
lbs/3 inches Note: All values in table are NOMINAL unless otherwise
specified
In the same way described earlier, the book configuration used for
testing was fabricated using eight layers of 3.7 lbs/1,000 sq. ft.
oriented netting sewn together along a single side edge to form the
"book". The testing showed that the book according to the present
invention was found to adsorb 9.60 pounds of oil per pound of
polypropylene netting. With the best of the three prior art
products, results of only 2.55 pounds of oil per pound of
polypropylene netting were obtained.
[0043] While the results obtained with the book configuration of
the oil capture and containment netting assembly were about 3-14
times better than the prior art pillow-style products, the bow tie
configuration netting assembly such as that shown in FIG. 1 was
found to have even greater effectiveness, as shown by the second
trial summarized in Table III below.
TABLE-US-00003 TABLE III Second Trial Bow Tie Testing Data Weight
of Weight of Weight water oil Average lb Weight of Weight of Bow
Tie after gain of mixture captured/lb Description of Weight of
Water Bow Tie Introduction Bow Tie after test lb captured/ of
polypro of Test # Bow Tie Oil grams grams grams gram grams grams lb
of polypro the two test 1 Stretched 1.1 C 129.6 400 4.73 46.02
41.29 481.2 8.73 net, 8 layers 2 Stretched 1.1 C 131.2 400 4.82
46.15 41.33 452.0 8.57 8.65 net, 8 layers 3 Stretched 1.1 C 236.4
400 8.84 176 167.16 499.0 18.91 net, 16 layers 4 Stretched 1.1 C
285.12 400 9.20 212 202.80 501.1 22.04 20.47 net, 16 layers 5
Stretched 1.1 C 558.92 600 16.1911 441.34 425.15 745.34 26.26 net,
32 layers 6 Stretched 1.1 C 560.12 600 17.1911 436.85 418.46 740.89
24.34 25.30 net, 32 layers 7 Stretched 1.1 C 860.67 600 24.7511
603.56 578.81 852.3 23.39 net, 64 layers 8 Stretched 1.1 C 854.29
600 23.5531 619.94 578.81 876.2 25.32 24.35 net, 64 layers 9
Stretched 1.1 C 0.6171 3.45 5.59 net, 1 layers
[0044] While not intending to be bound by the following technical
analysis in this paragraph, it is believed that the improved
effectiveness of the bow tie configuration is due in part to the
larger surface area presented to the oil. In the book
configuration, the "pages" do not create net cavities or an open
cell structure and, therefore, the book configuration has a less
than optimal oil retention ability when being removed from the
oil-contaminated water. In the prior art pillow configurations, the
affinity of the oil for the outside of the pillow effectively
blocks additional oil from being adsorbed into the center of the
pillow. In addition, as noted previously, the bow tie configuration
yields improved results over conventional pillow designs as well as
the book configuration due to the crimping and the resulting
creation of net cavities on each side of the crimp(s). These net
cavities allow for greater oil retention both while the oriented
netting assembly is in service and as the assembly is being removed
from the water.
[0045] Test results of the effectiveness of oil capture and
containment oriented net or netting assemblies in the bow tie
configuration are summarized by the second trial as set forth in
Table III. In the second trial, five bow tie netting assemblies
made of oriented clear (C) polypropylene netting having a weight of
1.1 lbs/1,000 sq. ft. were tested over a series of nine tests. A
specification sheet for this commercially available clear netting
is set forth hereinafter in Table IV. In addition, a specification
sheet for black netting of the same weight is provided thereafter
in Table V.
TABLE-US-00004 TABLE IV Product LW011C Structure Type Light
Weight-Oriented Polymer Type Polypropylene Color Clear/Natural Unit
Weight 1.1 lb./M Ft.sup.2 MD & TD Mesh Size 0.25'' .times.
0.25'' Target MD & TD Tensile Strength 5.0/4.0 MD/TD min. lbs/3
inches Note: All values in table are NOMINAL unless otherwise
specified
TABLE-US-00005 TABLE V Product LW011B Structure Type Light
Weight-Oriented Polymer Type Polypropylene Color Black Additives
Min. 0.1% Carbon Black Unit Weight 1.1 lb./M Ft.sup.2 MD & TD
Mesh Size 0.25'' .times. 0.25'' Target MD & TD Tensile Strength
5.0/4.0 MD/TD min. lbs/3 inches Note: All values in table are
NOMINAL unless otherwise specified
[0046] In the second trial, the first oriented netting assembly had
eight layers (Tests #1 and #2), the second oriented netting
assembly had 16 layers (Tests #3 and #4), the third oriented
netting assembly had 32 layers (Tests #5 and #6), the fourth
oriented netting assembly had 64 layers (Tests #7 and #8), and the
fifth oriented netting assembly had one layer (Test #9).
[0047] As is evident from the results, the best performance was
obtained during Tests #5-6 and Tests #7-8, using bow tie netting
assemblies having 32 and 64 layers, respectively. As a result of
both these trials and additional testing, it has been determined
that when layered between 16 and 64 times, the bow tie netting
assembly 10 initially captures and contains a quantity of oil
approximately 20 to 25 times the initial weight of the net or
netting. Once the oil in the netting is removed, such as by
pressing or other removal process, the netting assembly 10 may be
reused and, during multiple re-uses, has been found to repeatedly
capture and contain a quantity of oil approximately 15 to 16 times
its weight during each subsequent use. Results obtained during
testing to determine the effective capture and containment
quantities of a bow tie netting assembly as configured in FIG. 1
and having 32 layers after multiple uses are set forth in Table VI
(Test #11 and Test #12) which follows.
TABLE-US-00006 TABLE VI Fourth TrialDetermination of effective
capture and containment after multiple uses Weight of Weight of
Weight of Weight of Bow Tie after Weight of Bow Tie before Bow Tie
after Weight of Bow Tie after Weight of introduction 3.sup.rd
Description of Weight of Water introduction introduction Bow Tie
introduction 2.sup.nd Bow Tie introduction Test # Pillow Oil grams
grams grams grams after press time grams 2.sup.nd press grams 11
Stretched 560.12 600 17.19 435.65 27.19 434.34 1.1 C net, 32 24.34
14.97 layers lbs absorbed per lb of polypro 12 Stretched 17.56
442.6 25.8275 445.2 26.2479 442.16 1.1 C net, 32 24.21 16.24 15.85
layers lbs absorbed per lb of polypro
[0048] In addition, the oriented netting assemblies work quickly,
with each netting assembly achieving substantially its maximum oil
capture and containment capacity in approximately 10 minutes.
Results obtained when testing a bow tie netting assembly as
configured in FIG. 1 and having 16 layers to determine the
adsorption rate over time are set forth in Table VII below.
TABLE-US-00007 TABLE VII Third Trial Determination of adsorption
rate over time Weight of Bow Weight of Bow Weight of Bow Weight of
Bow Description of Tie before Tie after Tie after Tie after
adsorption rate Weight of Oil Weight of introduction introduction
10 introduction 20 introduction 30 Test # over time grams Water
grams grams min grams min grams min grams 1 Stretched 1.1 C 286.4
480 8.84 166.22 174.12 176 net, 16 layers 17.80 18.69 18.91 lbs
absorbed per lb of polypro
[0049] As shown in Table VII, the weight gain measured in the
netting assembly after 10 minutes was significant, while each
subsequent 10 minute interval thereafter yielded small additional
oil adsorption returns. In Table VII, the three weight values of
the bow tie assembly as set forth in the first row (166.22, 174.12
and 176) represent the actual weights of the bow tie samples after
10, 20 and 30 minutes, respectively. The three values appearing in
the second row immediately under the first row represent the
respective ratios of the amount of material adsorbed (determined by
subtracting the initial bow tie sample weight from the weight
values in the first row) divided by the initial weight of the bow
tie sample (8.84) for each of the 10, 20 and 30 minute
increments.
[0050] Once the oriented net or netting assemblies with their
captured oil quantity are removed from the water, the oil can be
removed and refined for subsequent use. Various methods of removal
may be employed as would be understood by persons of skill in the
art. According to one preferred method, the oil is pressed out of
the net or netting assembly by applying squeezing pressure to the
netting, as one would squeeze a sponge or wring out a mop with two
rollers, and collecting the oil that is thereby "wrung out".
[0051] In addition, during sequential testing of the bow tie
oriented netting assemblies in water contained in the pool
described above, each assembly was found to effectively capture oil
released in the pool by pulling the assembly back and forth through
the oil. Alternatively, the netting assembly according to the
present invention also worked effectively to capture the oil when
the water was agitated to create waves, as by lifting and lowering
one side of the pool. This performance capability in response to
"wave action" makes the bow tie netting assemblies excellent
candidates for oil spill clean-up in seas, oceans or other open
water where natural water wave movement is typically
encountered.
[0052] Further, the open mesh structure according to the present
invention, with the irregular channels or openings through the
assembly, has the advantage of maximizing the surface area of the
polypropylene that the oil can adhere to, thereby improving its oil
capture capabilities relative to a more solid structure, such as a
sock filled with absorbent material, or a net in which all of the
openings are regular and extend entirely through the assembly such
that a straight object such as a rod could be pushed entirely
through the structure's openings.
[0053] The foregoing descriptions and drawings should be considered
as illustrative only of the principles of the invention. The
invention may be configured in a variety of shapes and sizes and is
not limited by the dimensions of the preferred embodiment. Numerous
applications of the present invention will readily occur to those
skilled in the art. Therefore, it is not desired to limit the
invention to the specific examples disclosed or the exact
construction and operation shown and described. Rather, all
suitable modifications and equivalents may be resorted to, falling
within the scope of the invention.
* * * * *