Note: Descriptions are shown in the official language in which they were submitted.
2145118
..
-1- PATENT
HEAT RESISTANT CONTAMINATION CONTROL BOOM
BACKGROUND OF THE INVENTION
Field of the Invention
This invention relates generally to a flotation
barrier or boom, and, more particularly, to an improved
contamination control boom of the type which is
collapsible for more compact storage, and which has
improved heat resistance properties, making the boom able
to contain a burning surface contaminant for long
periods.
Description of Related Art
The increasing frequency of contamination of
bodies of water such as harbors, rivers, lakes, oceans,
and the like, by spills of contaminants, e.g. petroleum,
petroleum products, or other chemicals, has increased the
need for effective contaminant containment and disposal
equipment. Particularly, containment barriers or booms
are utilized to separate the area of a body of water
having a contaminant on the surface thereof from adjacent
areas of the body of water. Typically such booms
comprise a flotation portion to provide buoyancy, which
rises above the surface of the water, and a weighted
curtain or skirt portion which extends down into the
water to a distance effective to prevent contaminants
~ from escaping underneath the flotation portion of the
boom. .
.Because such booms are necessarily relatively
long, and are desirably stored so as to be quickly
deployable in the area of a contaminant spill, it is
advantageous to provide a boom which is collapsible, so
that a smaller volume of space is required for storage,
and so that it is more easily transported. However, the
boom should be capable of quickly being put in service,
and it has been found that storing such a containment
boom in a collapsed condition wound on a reel or drum,
Docket No.: KPLAS-35356
X145118
1
-2- PATENT
and having the ability to spring quickly to its intended
shape when free of the storage reel, satisfies these
conditions. In order to do so, the boom should be made
flexible for storage, and yet, the boom structure must be
adequately stiff and damage resistant to function
properly when deployed.
A further desired attribute is that the boom be
fire resistant. It is often the case that a flammable
contaminant is to be contained, or that such a
contaminant is purposely burned when contained. For
example, in-situ burning of spilled petroleum is
recognized as a desirable clean-up response, as the
harmful effects of the emissions of the products of
combustion are thought to be much less damaging to the
environment than the effects of spilled oil contaminating
shoreline, sea floor, and wildlife.
Consequently, the boom must be constructed so
as to be able to perform its containment function while
withstanding the high temperatures associated with
burning of contaminants for extended periods, which may
last several days. Certain woven ceramic fiber materials
have a sufficiently refractory nature that their physical
properties will remain unchanged under such conditions,
and are sufficiently flexible to form an outer skin of
the boom. However, such materials may be somewhat
porous, or may be punctured, and thus not be suited to
containing air to provide flotation.
It has been recognized by those concerned with
the art that a separate float, which is capable of
maintaining the buoyancy of the boom independently of the
porosity of the outer layer or layers of the material
from which the boom is constructed, is a solution to this
problem. Conventionally, this is done by placing float
material, such as a closed-cell foam material, within the
float portion of the boom.
Conventional float materials such as closed-
Docket No.: KPLAS-35356
.~ 214~i 18
-3- PATENT
cell foams may be relatively stiff, and therefore
unsuited to the bending inherent in compact storage,
deployment and use of a boom of this type. Further,
conventional closed-cell foams otherwise suitable for
this application will break down at temperatures to which
they may be required to be exposed for long periods in a
containment boom application for burning surface
contaminants. Some present devices employ a flotation
material having refractory properties. However, such
relatively refractory materials tend to be more stiff in
comparison to conventional float materials such as foams
formed from polymeric resins having otherwise similar
closed-cell characteristics. Consequently, booms using
such refractory flotation materials are relatively heavy
and more difficult to store compactly, as the flotation
portions of such booms do not deform as readily.
Another consideration in the design of booms is
that they must be constructed so as to remain functional
in adverse conditions such as rough water surface
conditions or a very rapid deployment in an emergency.
Again, flexibility and light weight are important factors
in allowing the boom to function as required. Yet high
strength requirements of materials employed
conventionally also implies a stiffer overall
construction, and hence presents a dilemma to those
concerned with providing a serviceable boom construction
which is compactly storable.
.Similarly, it has been recognized that
providing a flexible float within the boom is desirable,
yet conflicts with the requirement that the boom be
capable of functioning in the very high temperatures that
may be associated with containing a burning surface
contaminant over a long period of time. Conventional
float materials must be somehow shielded from heat that
may damage them, implying further structure adding bulk
and/or stiffness, or the use of refractory float
Docket No.: KPLAS-35356
X145118
-4' PATENT
materials requiring less protection that are themselves
more stiff.
In light of the forgoing, it has been
recognized that the desirable attributes of a contaminant
containment boom of this type should include suitable
containment capability even when exposed to the intense
heat of burning contaminants such as spilled crude oil,
for example. Also desirable Are flexibility and
durability for ease of deployment and use, even for long
periods, and collapsibility and flexibility for more
convenient storage and transport. Convenience of storage
and transport allows the boom to be more accessibly
located in relation to potential contaminant sources,
thus giving rise to the potential to reduce the damaging
effects of a spill.
These attributes being recognized, those
skilled in the art will appreciate that the design of
containment booms is difficult because of the often
conflicting requirements placed on materials used. What
is needed is a containment boom with durable, flexible,
buoyant, heat resistant, flotation that is at once
flexible and collapsible for convenient storage,
transport, deployment and use, and also ruggedly
constructed so as to reliably survive adverse conditions
of use without loss of function. The present invention
addresses these concerns.
SUN~MARY OF THE INVENTION
.Briefly, and in general terms, the present
invention provides an improved contaminant containment
boom combining collapsible and rugged construction with
improved flexibility and heat resistance. The boom
construction includes a flotation portion formed from a
collapsible support structure which supports a heat
resistant outer covering, for example of a woven
refractory material, over a porous spacing layer, such as
Docket No.: KPLAS-35356
~14511~
-5- PATENT
a corrugated wire mesh, in turn placed over another
covering of woven refractory material. An air gap is
formed between the layers of refractory material, for
example by the corrugations of the mesh, giving rise to
a an increased thermal gradient across the layered cover.
The boom in accordance with the invention also
provides a flexible float assembly within the flotation
portion movably connected to the support structure to
allow limited relative movement between the float
assembly and the support structure of the boom. An air
gap is formed between the float assembly and the outer
covering above a water level within the flotation portion
of the boom by the support structure.
In a more detailed aspect, the float assembly
includes non-continuous lengths of laminated closed-cell
foam having transverse slots at preselected intervals
along an outer edge of each laminated layer. The
laminated layers are joined only in the center region of
the non-continuous lengths of foam, allowing relative
slip between the layers, increasing with distance from
the center, facilitating bending. These laminated layers
of closed cell foam are covered by a layered covering
having an outer refractory layer formed from a woven
ceramic fiber material and at least one layer of spacing
material such as corrugated wire mesh, as well as at
° least one layer of liquid absorbent material which may be
selected from the group including closed-cell foams,
semi-closed cell foams, woven and non-woven ceramic or
polymeric fiber fabrics or battings. Provision is made
for water to enter the flotation portion which in turn
may wick up 'into one or more water absorbent layers
covering the flotation foam portion of the float assembly
via access provided in the covering at a bottom location
of the float assembly located in a bottom interior
portion of the float portion of the boom. Water wicked
up into an absorbent layer is allowed to escape from the
Docket No.: KPLAS-35356
2145118
-6- PATENT
float assembly as steam, thereby taking full advantage of
the latent heat of vaporization which continually occurs
once begun, water being supplied by wicking action, and
heat is removed in this way from the float assembly and
providing a cooling effect.
The provisions for escape of steam from the
boom can include incorporation of porous layers in the
covering of the float assembly, as'well as vents placed
at intervals therein, as well as vents in the outer
covering of the flotation portion. Vents in the outer
covering are advantageously constructed with openings
formed in the outer layer of woven ceramic material
offset from openings in the inner layer of woven ceramic
material, with the intervening corrugated mesh material
being continuous, so as to allow and steam to escape from
the flotation portions without allowing radiant heat to
be admitted through the vents in the outer cover. These
vents also allow air to be admitted or expelled from the
flotation portion as it expands or contracts as the boom
is being deployed or recovered from or onto a storage
reel.
In more detail, improved flexibility is
imparted by providing a pivotable connection between the
support structure, such as a helical coil supporting the
flotation portion and the outer covering along the bottom
center of the interior of the flotation portion, and
connecting the float assembly to the collapsible support
structure as mentioned above, in connection with
providing improved flexibility to the float assembly
itself. Flexibility of the float assembly is enhanced by
providing transverse slots along the edges of the
laminated layers of the floats and by providing for
relative slip between layers of laminated float material
contained in the float assembly, facilitating bending in
horizontal and vertical planes. Also, flexibility is
enhanced by providing a non-continuous laminated
Docket No.: KPLAS-35356
~1~5118
- PATENT
construction wherein the layers of the float assembly
periodically terminate forming discrete float portions
within the continuous float assembly. Also, pleats are
provided at intervals in the continuous outer layer of
the float assembly to further facilitate bending.
In a further more detailed aspect, stress
relief joints are provided at intervals in the outer
covering of the flotation portion'of the boom, and as
will be apparent to one skilled in the art, the boom may
be provided in sections of predetermined length and the
joints periodically disposed between these sections are
configured to also allow relative slip between elements
providing stress relief and additional flexibility.
These joints, as well as the strain relief portions
provided in the outer cover, also supplement the vents
described above in allowing water, air, or steam to enter
or escape from the interior of the flotation portion as
required.
As is known in the art, the boom may be
comprised of joined sections of shorter length. The
joints between boom sections, while allowing relative
slip as required between elements, and flexibility, are
also configured to provide uniform boom function and
attributes across the joint. In this regard the
adjoining sections of support structure, for example
helical coil members, are made to abut. Finished ends
are provided for example by laying up adjoining coil
sections so as to overlap for a selected distance. A
small diameter coil spring is placed upon the overlapping
coils and stretched to wrap the coils together to act as
one along the overlapping portion forming a finished end.
A wire mesh joint cover having diagonally oriented edges
in relation to a longitudinal axis of the boom is
provided over the coil in the area of the joint, and an
outer joint covering is provided over the outer covering
of the flotation section. These allow stress relief and
Docket No.: KPLAS-35356
-- X145118
-$- PATENT
the escape of air and steam from the boom, continuity of
the boom containment function across the joint; and
smooth function of the support member compression and
expansion.
Other features and advantages of the invention
will become apparent from the following detailed
description, taken in conjunction with the accompanying
drawings, which illustrate, by c5ay of example, the
features of the invention.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a elevational view of the boom of the
invention being deployed;
FIG. 2 is a perspective view of a portion of
the deployed boom shown partially in cut-away;
FIG. 3 is a medial elevational cross section
view of the deployed boom resting on the surface of a
liquid body.
FIG. 3a is a medial elevational cross section
view of a portion of the boom shown in FIG. 3
FIG. 4 is a detailed medial elevational cross
section view of the float assembly shown in FIG 3;
.FIG. 5 is a fragmentary longitudinal
elevational cross sectional view of a portion of the
float assembly shown in FIG 4;
FIG. 6 is an elevational view, partially in
cut-away of a joint portion of the boom of the invention;
FIG. 7 is a developed plan view of an inner
joint cover shown in FIG. 6;
Docket No.: KPLAS-35356
'~ ~.14~1~~
-9- PATENT
FIG. 8 is a sectional view through a strain
relief portion of the outer cover; and
FIG. 9 is a developed plan view of the outer
cover of the boom at a strain relief portion.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
As shown in FIGURE 1 of the drawings, which are
provided for purposes of exemplary illustration, the
invention is embodied in a contamination control boom 10
having a flotation portion 12 and a weighted curtain or
skirt portion 14. The boom is stored and deployed from
a reel 16. The reel is preferably rotatably mounted upon
a platform 18 such as a vessel, dock or trailer, and the
reeled boom is easily transportable.
As will be apparent to those skilled in the
art, the boom 10 is in a compressed condition when wound
on the reel 16. The boom 10 returns to an expanded
operating condition when it is free of the reel 16, which
will be further described below. The flotation portion
12 in this example is generally circular in cross section
in its fully deployed and expanded condition and provides
a freeboard substantially greater than that provided by
an internal foam. flotation portion (not shown) alone.
~ The weighted skirt portion 14 extends down below the
flotation portion into the water when the boom is
deployed to cut off the escape of floating contaminants
below the~underside of the float portion.
Turning now to FIG. 2, the general
configuration of the boom 10 is shown, the flotation
portion 12 being generally tubular and containing a float
assembly 20 inside. The skirt portion 14 depends from
the flotation portion and is weighted by a chain 22
enclosed in a weight casing 24 formed in the bottom of
the skirt portion. Other configurations for the
Docket No.: KPLAS-35356
X145118
-10- PATENT
flotation portion than the one illustrated could be
employed, for example compressible or non-compressible
stand-off cover supports or frames (not shown) could
connect the float assembly 20 to an insulating cover
defining the flotation portion 12 . The flotation portion
also may have a different shape depending on the
particular compressible or non-compressible support
structure used, and may be closed, or vented to the water
or atmosphere outside.
As will become apparent to one skilled in the
art from the illustrated embodiment, and should be
understood to apply to other configurations, provision of
an air gap to provide a thermal boundary layer between
the environment outside the floatation portion 12 of the
boom 10 and the float assembly 20 inside allows the float
assembly to be made of lower temperature tolerance
materials, including more flexible foam materials.
Additionally, while not specifically discussed,
other ways of implementing the principles of the
invention will suggest themselves to those skilled in the
art. For example, providing a flexible separate heat
resistant outer structure which may incorporate the air-
gap and other features described herein, capable of
fitting over a float assembly 20 such as described herein
or another configuration such as a standard circular
cross section float (not shown), being releasably
attached thereto when containment of burning contaminants
is desired, are intended to be included within the scope
of the invention.
As will be appreciated by one skilled in the
art the boom 10 is compactible by the skirt portion 14
simply folding up, and the flotation portion 12 being
provided with a compressible coil wire support 30 which
is pivotally attached to the interior of the flotation
portion at the bottom thereof by retaining straps 32
attached to the upper end of the skirt portion 14
Docket No.: KPLAS-35356
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-11- PATENT
engaging the bottom of the coils, allowing the coils to
rotate as the boom is rolled onto a reel 16 for example.
Additionally, the float assembly 20 is somewhat
deformable, allowing it to be compressed to a certain
extent in storage of the boom.
The flotation portion 12 is generally formed by
covering the coil with layers 34, 36, and 38 of various
materials which cooperate to form a heat resistant
contaminant impervious barrier around the coils 30,
thereby defining a generally tubular structure in a
deployed state. An outer heat-resistant cover 34 is
formed from a refractory material. A fabric of woven
ceramic fibers has been found to work well for this
purpose. The outer layer may be coated with a flexible
protective waterproof and abrasion resistant coating, for
example a silicone polymer. This coating can be applied
to one or both of the inner and outer surfaces of the
fabric. The coating may be sacrificed where exposed to
high temperatures, but will serve to protect the outer
refractory layer during handling for storage and
deployment, and will still allow it to be flexible.
The outer cover 34 is underlain by an inner
cover 35 defined by layers 36 and 38 around the upper
portion of the flotation portion. A spacing layer 36 of
a highly porous and bulky material, having a high
temperature tolerance, and having minimal contact with
the outer cover layer 34 and inner cover layer 38 serves
to provide an air gap between the inner and outer cover
layers.
As will be appreciated by those skilled in the
art, a thermal boundary layer providing a relatively
larger temperature gradient is provided across these
cover layers due to this insulating configuration. It
has been found that a continuous crimped heat resistent
stainless steel open weave mesh 36 formed, for example,
by crimping corrugations in a woven mesh of stainless
Docket No.: KPLAS-35356
2145118
-12- PATENT
steel wire, works well for this purpose. The spacing
layer of crimped mesh is an integral part of the inner
cover 35, and is securely attached thereto.
The crimped mesh layer 36 also increases the
puncture and tear resistance of the flotation portion 12
of the boom 10, and enhances its flexural strength.
The inner layer 38 of the inner cover 35 is
also a refractory material similar to the outer layer 34.
The weave of the ceramic fiber fabric is also tight
enough to preclude contaminants passing through the
material. This inner layer is coated on the outside with
a protective coating such as that described in connection
with the outer layer. The inner surface 39 of the inner
layer 38 is left uncoated and allows the coils 30 to move
more freely with respect to the inner surface. This is
desirable during deployment and recovery of the boom for
example, as the coils may slide against the inner surface
39 with relative movement of the coils and inner surface
as the coils lay over into a compressed configuration, or
deploy to an expanded configuration, as the boom is
reeled onto the reel 16 (not shown) or reeled off the
reel, respectively. Coating the outer side provides
abrasion resistance against the wire mesh 36.
The float assembly 20 positioned within the
flotation portion 12 comprises a laminated construction.
The outer two cover layers 40 and 42, comprised of an
outer layer 40 of a refractory material such as a ceramic
fiber fabric, and an underlying layer 42 of corrugated
wire mesh as described above in connection with the mesh
layer 36 in the inner cover 35 of the flotation portion,
are continuous between joints (not shown) in the boom 10
described below; whereas structures of laminated sub-
layers 44, 46, 48, 50, 51, as well as a laminated float
52 (all not shown) are not continuous but rather are
broken into relatively shorter sections defining separate
floats 41 to provide increased overall flexibility.
Docket No.: KPLAS-35356
'~ X145118
-13- PATENT
Regularly spaced slots 54 (not shown) are provided in the
outer periphery of the interior layers (not shown) of the
laminated float 52 which facilitate increased flexibility
in a sideways direction to complement increased
flexibility in a vertical direction facilitated by the
non-continuous structure of the interior layers and the
laminated float as will be described.
The float assembly 20 is movably attached to
the coils 30 by float assembly attachment rings 56 formed
from stainless steel wire. The rings engage the wire
mesh layer 42 of the float assembly at a bottom portion
where the mesh layer overlaps in providing closure of the
outer cover layers 40 and 42 around the inner layers of
the float assembly, and the stainless steel mesh is
doubled strength. This attachment allows limited
relative movement between the float assembly and the
coils and provides secure attachment at a double strength
portion of the mesh layer.
Further illustrated aspects of the boom 10
construction include attachment of the skirt portion 14
to the flotation portion 12. As shown in FIG 3, a
curtain portion 58 of the skirt portion is attached to
the outer float cover 34 of the flotation portion by
releasable twist-lock fasteners, allowing the outer float
cover to be independently removed. This is advantageous
as the outer float cover is most susceptible to damage
during training, containment and burning operations. As
will be apparent to one skilled in the art, a lower edge
portion.60 of the outer float cover is underwater during
operation of the boom, and consequently a non-refractory
leader portion 62 of a different material can be employed
in this area. The leader portion is sewn to the
refractory portion of the outer cover 34 with thread 64
formed from stainless steel or of polymer fibers such as
polyester.
Providing a leader portion 62 of different
Docket No.: KPLAS-35356
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-14- PATENT
materials is advantageous in that it can be chosen so as
to have good strength and flexibility properties for
installing fasteners 26. A polyurethane coated polyester
fabric has been found to work well. This increases the
durability of the boom 10 in use, and makes installation
of eyelet portions 25 of the fasteners for example
easier. The eyelets mate with the twist-lock fasteners
26 installed in the curtain 58 of the skirt 14, securing
the cover to the skirt.
The skirt portion 14 is attached to the coils
30 by coil retaining straps 32 as before described.
These straps are formed from polyurethane coated
polyester fabric and are fastened to the skirt portion,
which is formed from the same material. Additionally,
the skirt portion is provided at an upper end of the
curtain 58 with a Y-shaped configuration which may be
formed by securing a separate piece 65 of the same fabric
material as used to form the curtain to the upper end of
the curtain. Each upper branch of the Y-section of the
skirt forms a fabric connection flange for mounting the
fasteners 27 for connection to the inner cover layers 36
and 38 to complete the bottom portion of the inner cover
35 of the flotation portion 12 around the coils.
An inner cover leader 66 of flexible fabric
material similar to the leader portion 62 of the outer
cover 34 can be provided, again to provide a better
material in which to install eyelets for fasteners 27.
The leader is shown sewn by stitching 68 through both the
inner cover 38 and the corrugated mesh layer 36. The
stitching is again of high temperature stainless steel or
polymer fiber thread.
This configuration provides for separate and
independent removal of the inner cover 35 by
disconnection of twist-lock fasteners 27, similar to that
capability provided for first removing the outer cover 34
by disconnection of twist-lock fasteners 26.
Docket No.: KPLAS-35356
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-15- PATENT
The curtain 58 of the skirt portion 14 is
folded back at a bottom end and seamed to form a casing
24 for containing the weight 22. The weight can be
formed conventionally for example by a galvanized high
strength steel chain continuous through the length of the
boom 10.
The float assembly 20 is shown in FIG. 4,
illustrating features of the laiminated construction
mentioned above. An outer cover 70 is formed from the
outer layers 40 and 42 and is continuous throughout the
length of the boom (not shown) except at joints (not
shown) in the boom. Outer float cover 40 is formed from
a treated, continuous, flexible, woven ceramic fiber
fabric having refractory properties, for example a
silicious mineral compound coated fiberglass fabric.
This float cover layer reduces heat transfer into the
float assembly.
When the boom is initially exposed to a burning
contaminant, the float cover 40 is predominantly dry.
During an initial time period wherein it is dry, the
treated glass fabric protects inner float sub-layers
primarily by utilizing its thermal protection properties.
After the boom has been deployed on a water surface and
exposed to turbulence and a burning f luid for an extended
period of time water migrates into the boom through
various openings (not shown) as will be discussed below
and the float cover fabric becomes saturated with water
due to its wicking properties. This gives rise to an
insulation effect due to heat being removed from the
outer cover by means of latent heat of vaporization of
steam which is formed from water wicked into the cover
and thereafter escapes from the boom through various vent
openings described below.
As can be seen, the outer fabric cover layer 40
covers all the outside surface but a porous bottommost
part 72 of the float assembly 20. The fabric cover layer
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40 extends well below the surface of the water inside the
boom which will substantially equalize with respect to
the water surface outside of the boom facilitating the
wicking action described above.
The crimped corrugated wire mesh layer 42 forms
an inner layer of the float cover 70 and extends
completely around the float assembly 20 and overlaps in
the bottommost portion 72 facilitating closure by
crimping a stainless steel clamp 73 around and though the
two overlapping layers of wire mesh 42 in this area.
This construction is advantageous as it keeps the sub-
layers within the mesh layer together during assembly of
the float assembly.
The outer fabric cover layer 40 is sewn to the
underlying,mesh layer 42 by a durable thread, such as
stainless steel or polyester fiber thread, to bond the
two layers, thereby forming an integral layered
construction of the float cover 70 which is flexible and
puncture resistant. Increased flexibility in the float
cover 70 is provide by providing pleats 76 in the outer
fabric layer 40 of the float cover, as also shown in
FIG.5. Returning to FIG 4, the weave of the outer fabric
cover layer is tight and precludes any significant amount
of contaminants that may enter the float 10 from
reaching interior sub-layers of the float assembly.
The mesh layer 42 of the float cover 70 is
formed from a continuous, corrugated, crimped, stainless
steel wire, open weave mesh, similar to that described
above in connection with the spacing layer 36 of crimped
wire mesh formed in an outer layer of the inner cover 35
of the flotation portion 12. The mesh layer of the float
cover provides a thermal boundary layer between the
fabric cover 40 and the sub-layers below similar to that
described above in connection with the outer spacing
layer 36 of the inner cover 35 as it provides an air gap
between the outer fabric cover 42 and enclosed sub layers
Docket No.: KPLAS-35356
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-17- PATENT
except for intermittent contact of the steel wire mesh.
The mesh layer also comprises a flexible continuous
structural component of the float cover which in
combination with the outer fabric envelopes and
constrains the multi-layered and segmented float assembly
portions mentioned above formed by the non-continuous
laminated sub-layers forming individual laminated floats
as will be discussed below.
The mesh layer 42 of the float cover 70 also
. comprises a flexible structural member which may be
fastened to by the steel rings 56 movably attaching the
float assembly to the coil 30.
The float assembly further contains sub-layers
44, 46, 48, 50, 51, and laminated float 52. These
components are not continuous over the length of the boom
as mentioned, but are segmented into individual floats 41
to provide increased flexibility. Various layers 48, 50,
51 and 52 of the segmented individual floats are attached
from top to bottom by a large staple 78 formed from
stainless steel and by a small line of glue 79 applied
between each of the layers in the center region thereof.
After the inner sub-layers comprising the floats are
enveloped by the float cover 70 the bottommost portion of
the staple of each float is bent around the wire mesh
layer 42 at the bottommost portion of the assembled float
assembly. This construction further ties the float
assembly together, yet allows flexibility.
.An outer water-wicking layer 44 of the float
sub-assembly 41 is formed from a treated non-woven
ceramic cloth having desirable insulating and water
absorbing and wicking properties. A high-temperature
non-woven fiberglass cloth coated with a silica gel or
other silicious mineral compound having hydrophilic
properties may be used for example.
Like the outer fabric layer 40 of the float
assembly 20, this material functions differently to
Docket No.: KPLAS-35356
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-18- PATENT
provide an insulating effect depending on the conditions
to which it is exposed at any given time. When the boom
is initially deployed and the interior of the boom 10 is
predominantly dry thermal protection is provided by the
insulating effect of the multiple thermal boundary layers
inherent in the unwoven or batted disposition of the
glass fibers comprising the layer.
When the interior portion of the boom 10
becomes wetted, this wicking layer 44 functions to draw
water from the bottom area 72 of the float assembly 20
admitted by the porous mesh layer 42 in that area, and
wick it up and around the top of the layer, completely
saturating the layer with water. This water is converted
to steam, and the fabric will thereafter continually draw
water up over the inner float sub-layers for conversion
to steam. This process enhances the insulation capacity
of the layer as it maintains a temperature of the boiling
point of water, excess steam being able to migrate into
porous sub-layers, and out through the float cover 70 to
be vented from the boom 10 dissipating heat thereby.
A porous foam layer 46 is provided beneath the
wicking layer 44. This layer is composed of an semi-
closed cell polymeric foam capable of resisting
relatively high temperatures, for example such a foam
formed from polyamide resin. This layer provides thermal
insulation and reserve buoyancy in the float assembly 20.
After the boom 10 has been exposed to elevated
temperatures inherent in a fire for a short period,
usually about twenty minutes, steady state conditions are
attained within the flotation portion 12 of the boom.
Steam generated within the wicking cloth layer 44
permeates down into the porous foam forming a thermal
boundary layer of approximately 213 degrees fahrenheit.
Another layer 48 of mineral coated non-woven
fiberglass cloth is provided beneath the porous foam
layer 46. This second wicking layer 48 functions in
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-19- PATENT
substantially the same manner as the wicking layer 44
discussed above, only from below the porous layer.
Below this second wicking layer 46 two separate
layers 50 and 51 of high temperature resisting closed
cell foam are provided. A closed cell foam formed from
polypropylene resin may be used for example. These
layers provide further thermal barrier function and
reserve buoyancy in the float assembly.
Lastly, a laminated float 52 is provided within
the above described layers. The layers cooperating as
described to thermally insulate this float from the high
temperatures to which the boom 10 is intended to be
exposed. The provision of layers 52a, 52b, 52c, 52d
allows for relative movement therebetween, resulting in
improved flexibility. As will be apparent to one skilled
in the art a large number of layers is preferred, and the
layers shown could be further multiplied to eight or
sixteen for example by decreasing the thickness of each
layer. The laminated float is formed from a closed cell
polymeric foam, for example a closed cell foam formed
from polyethylene. Such a material is very buoyant and
also flexible and low in cost of manufacture. The
layered insulating configuration of the float assembly 20
allows this relatively low temperature resistant material
to be employed.
Also the float assembly 20 is given a shape
which conforms to the coil 30 to which it is attached by
staggering the widths of the layers 52a, 52b, 52c, and
52c, to form a roughly trapezoidal laminated float 52
section. Taking FIG. 4 in conjunction with FIG. 5, it
will be appreciated that the outer edges are provided
with slots 54 which allow increased flexibility of the
float 52 in the horizontal direction as will be
understood by one skilled in the art.
As can best be appreciated with reference to
FIG. 5, the laminated floats 52 are axially aligned
Docket No.: KPLAS-35356
2145118
-20- PATENT
within the continuous float cover 70 having a pleat 76
spaced at periodic intervals, such as approximately four
foot intervals, in the outer fabric layer 40. The outer
wicking layer 44 is folded over at an edge portion 80 at
each end of the float to encapsulate the sub-layers 46,
48, 50, 51, and the laminated float 52. This provides an
easily handled sub-assembly in manufacturing the boom 10,
as well as giving the increased flexibility properties
discussed in connection with the float assembly.
Moreover, it will be appreciated that in a similar manner
the outer cover 70 is folded over and enclosed at joints
(not shown) in the boom as the float assembly is
conveniently non-continuous through such joints, thereby
allowing ready separation.
FIG. 6 illustrates the configuration of a joint
82 between sections of the boom 10. Such joints
facilitate manufacture of the boom and also function to
provide venting in the covers 34, 35 over the coil 30 as
hot gases escape from within the boom. Also as will be
apparent to those skilled in the art the joints provide
a capability to make discrete boom sections releasable,
for example to remove a section to make repairs in the
field.
The joint 80 is effected by terminating the
coil 30 by lashing an overlapping end portion 85 together
with and uncoiled stainless steel spring 95 of suitable
diameter to effect a good connection and by providing
releasable fastener portions 83 incorporating grommets 84
compatible with twist-lock fasteners, and reinforcing
materials as are well known in the art in the curtain 58
of the skirt portion 14 at the joint. The weight chain
22 is provided with a releasable connector 88 at the
joint and is lashed to the casing 24 of the skirt portion
by polyester fiber rope 87 fed through grommets 89
provided in the casing and the links of the chain 22.
With reference to both FIGS. 6 and 7 a wire
Docket No.: KPLAS-35356
'- ~14~118
-21- PATENT
mesh coil joint cover 90 is provided, enclosing the coil
over the joint portion 80 where the covers will not be
continuous. This cover can be formed from the same type
of stainless steel mesh employed elsewhere in the boom 10
construction, but is preferably flat. The edges aligning
with the axis of the boom are provided with a reinforced
leader 91 construction where the mesh 92 is sandwiched
between layers of polymer coated' fabric 93 such as
polyurethane coated polyester fiber fabric by sewing with
stainless steel or high temperature resistant polymer
thread (not shown) and provided with grommets 94 adapted
to interfit with twist lock fasteners 27 connecting the
y-portion of the skirt portion 14 to the inner cover 35.
The edges 96 extending diagonally are protected
by a strip of coated fabric material forming an edge
cover 96 by being wrapped around the edge and sewn with
stainless steel stitching (not shown) in a double row.
the cover may be formed for example by a coated ceramic
fiber material such as is employed in the inner cover 35
of the boom.
Referring to FIG. 6 the joint 80 is further
protected by an outer joint cover 100 formed from a
polymer coated fabric material. This material may be for
example the coated polyester material described above in
connection with the inner cover leader portion 62. It
will be understood by one skilled in the art that the
portion of this outer cover exposed to burning
contaminants may be sacrificed. The outer cover is
provided with grommets 102 for releasably affixing the
outer cover to the boom 10 by means of the twist-lock
fasteners 104 provided in a row in the curtain 58 of the
skirt 14. As will be apparent other types of releasable
fasteners may be used instead of those described herein.
The outer joint cover 100 protects the inner
float chamber of the boom 10 should it become exposed
through the joint 80 between the section covers.
Docket No.: KPLAS-35356
~~4~118
-22- PATENT
The outer joint cover 100 also contains a
central region 106 formed from a layer of coated
refractory material such as coated silica fiber fabric,
as described above in connection with the outer cover 34,
positioned on the inner surface of the joint cover 100
over the joint 80. The portions of the cover assembly
100 above the waterline, except for the central region
106, will be expected to be sacrificed when exposed to
burning contaminants.
The joint portion 80 described also allows
steam to escape from within the flotation portion 12 of
the boom 10 through the non-continuous outer cover 34 at
the joint 80. Additionally, vent holes 110 and 111 may
be periodically provided in the inner and outer heat
resistent coil cover layers 34 and 38, respectively,
along the length of the boom to allow steam to escape.
Such vents are positioned near the top of the boom and
are offset as to the inner and outer cover layers so that
radiant heat energy is prevented from directly entering
the boom. As will be appreciated by one skilled in the
art steam travels in the air gap formed by the spacing
layer 3 6 of wire mesh between the inner and outer vent
holes 111 and 110 respectively.
Referring to FIGS. 8 and 9 strain relief
portions 112 are provided periodically along the length
of the boom 10 com risin a non-continuous
P g portion of the
outer cover 34 underlain by a strain relief protective
cover portion 114 which is stitched along edge portions
116 to the inside surface of the outer cover 34, but left
free along edge portions 118. As will be appreciated by
those skilled in the art this feature provides for strain
relief of the outer cover in bending of the boom 10.
Edge portions of the strain relief portion 112
are wrapped in a reinforcing strip 122 of coated
refractory cloth such as described for use in the inner
coil cover layer 38, and sewn in multiple seams with
Docket No.: KPLAS-35356
CA 02145118 1999-08-10
-23- PATENT
stainless steel thread 124.
A removable tow adapter (not shown) may be
provided at the end of the boom for closing off the
opening at the end of the flotation portion to prevent
excessive water ingress into the boom during towing and
for providing selective attachment of a tow line used to
deploy and position the boom in a body of water. The tow
adapter advantageously is formed for the most part of a
non-refractory material, and has a sack-like
configuration with an open end fitted onto the end of the
boom and a closed end attached to the tow line. The open
end is fitted onto the boom in such a way that the
adapter material either overlaps or underlaps the coil
covers, depending upon the direction of tow, so as to
prevent the ingress of excessive amounts of water into
the boom through the region of overlap or underlap while
the boom is being towed. The chain in the skirt portions
of the boom is removeably attached to the closed end of
the adapter to keep the chain in tension during towing.
An opening with a wire mesh is provided in an
upper surface of the adapter adjacent the end of the boom
to allow heated vapors to escape from the interior of the
boom. A float is positioned inside the adapter between
the closed end and the mesh covered opening. The surface
of the float closest to the opening is covered with
refractory material to protect the float from the heat of
the escaping vapors.
From the foregoing it will be appreciated that
the high temperature resistant boom 10 of the invention
provides advantages in flexibility, continuity of boom
function in containing contaminants along its entire
length, lightness in weight, fire resistance, ease of
storage, deployment and repair over prior art booms of
this general type, without sacrificing durability and
manufacturability.
While a particular form of the invention has
Docket No.: KPLAS-35356
~l~~ll8
-24- PATENT
been described, it will be apparent that various
modifications can be made without departing from the
spirit and scope of the invention.
Docket No.: KPLAS-35356
