Note: Descriptions are shown in the official language in which they were submitted.
CA 02929339 2016-05-09
FLOATING ROOF FOR STORAGE TANKS
BACKGROUND
[0001] Embodiments relate generally to a floating roof for use in storage
tanks. More
particularly, embodiments relate to a system and a method of producing a
floating roof.
[0002] Currently, floating roof designs maybe time consuming to build and may
require
large amounts of onsite welding. This may lead to large labor cost and quality
control issues.
Additionally, floating roofs may be welded together and connect to a single
rim. The single rim
may be welded to many different pontoons that make up the floating roof This
may add
additional labor time and cost to floating roof construction. In an effort to
reduce material, cost,
labor, and construction time, a pontoon is needed that may be easy to
construct, cheap to
produce, and quickly installed.
SUMMARY OF THE INVENTION
[0003] According to one aspect of the present invention there is provided a
floating roof
system comprising:
a floating roof comprising a plurality of pontoons arranged to form the
floating roof,
wherein the plurality of pontoons each comprise a lower panel, a plurality of
outer walls
disposed at the edges of the lower panel, and a plurality of stiffeners
disposed adjacent the
lower panel; and
a plurality of attachment points attached to the floating roof, wherein the
attachment
points are configured to couple the floating roof to a storage tank.
[0004] The lower panel and outer walls may be attached at a formed corner.
[0005] The outer wall may further comprise a ledge.
[0006] An upper panel may be attached to the ledge.
[0007] The plurality of stiffeners may be c-channels.
[0008] The plurality of attachment points may be located on the edge of the
outer wall.
[0009] The plurality of attachment points may be D-rings.
- 1 -
CA 02929339 2016-05-09
[0010] The lower panel may further comprise panel clips, wherein the panel
clips are
disposed on the edge of the lower panel opposite the outer walls.
[0011] The floating roof may further comprise a segmented rim, wherein each
individual
segment of the segmented rim is attached to an individual outennost pontoon.
[0012] The floating roof may further comprise a plurality of supports coupled
to the
floating roof for supporting the floating roof from a storage tank roof.
[0013] According to a second aspect of the present invention there is provided
a method
of connecting a plurality of pontoons to fon-n a floating roof comprising:
attaching adjacent pontoons of the plurality of pontoons to one another with
one or more
panel clips;
welding the adjacent pontoons to one another; and
welding a rim to a portion of the outennost pontoons that fonn the floating
roof, wherein
the rim is welded to at least a lower panel of each of the outermost pontoons.
[0014] According to the method, at least a portion of the plurality of
pontoons may
comprise a lower panel, an outer wall may be disposed at the edges of the
lower panel, and a
stiffener may be disposed adjacent the lower panel.
[0015] According to the method, the outer wall may further comprise a ledge.
[0016] According to the method, an upper panel may be welded to the ledge.
[0017] According to the method, the stiffener may be a c-channel.
[0018] According to the method, the panel clips may be attached using nuts and
bolts.
[0019] According to the method, the outennost pontoon may have a radial edge.
[0020] According to a further aspect of the prescrit invention, there is
provided a method
of fabricating a pontoon comprising:
forming a lower panel and an outer wall with a formed corner;
bending the outer wall to forrn a ledge; and
attaching an upper panel to the ledge.
[0021] The method may further include disposing a plurality of stiffeners
between the
lower panel and the upper panel.
[0022] The method may further include disposing at least one attachment point
to the
outer wall.
- 2 -
CA 02929339 2016-05-09
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] These drawings illustrate certain aspects of some of the embodiments of
the
present invention and should flot be used to limit or define the invention.
[0024] Figure 1 illustrates a side perspective view of a floating roof system;
[0025] Figure 2 illustrates a top perspective view of a pontoon;
[0026] Figure 3 illustrates a fon-ned corner;
[0027] Figure 4 illustrates a top perspective view of an open pontoon;
[0028] Figure 5 illustrates a top perspective view of a pIurality of attached
pontoons;
[0029] Figure 6 illustrates a bottom perspective view of a plurality of
attached pontoons;
[0030] Figure 7 illustrates a side perspective of a rim attached to an
outermost pontoon;
and
[0031] Figure 8 illustrates a top perspective of a rim attached to an
outermost pontoon.
DETAILED DESCRIPTION
[0032] Embodiments relate generally to a floating roof for use in storage
tanks. More
particularly, embodiments relate to pontoons that may be used with other
pontoons to fonn a
floating roof, which may prevent the evaporation of chemical fluids. In
embodiments, a pontoon
may comprise a lower panel, an outer wall, a stiffener, an upper panel, and a
panel clip. The
pontoon may attach to other pontoons, forming a floating roof, which may be
placed upon a
chemical fluid. Pontoons may connect to other pontoons through panel clips
and/or directly
welding pontoons to adjacent pontoons. In embodiments, outermost pontoons,
adjacent a storage
tank, wall may further attach to a rim. The rim may act as a buffer between
the outermost
pontoons and storage tank wall, allowing the floating roof to move as
chemicals are added or
removed from the storage tank. Advantageously, the pontoons disclosed herein
may reduce the
material, cost, labor, and construction time associated with production of a
floating roof
[0033] Figure 1 illustrates an embodiment of floating roof system 2. Floating
roof system
2 may be housed within a storage tank 4. Storage tank 4 may comprise a storage
tank wall 6 and
a storage tank roof 8. Storage tank 4 and storage tank roof 8 may comprise
a.ny suitable material
for storing a chemical fluid 10. Suitable materials may be, but are flot
limited to, stainless steel,
aluminum, steel, black iron, and/or any combination thereof. Chemical fluids
10 that may be
- 3 -
CA 02929339 2016-05-09
stored within storage tank 4 may comprise petroleum products, crude ou, liquid
chemical
compounds, and/or any combination thereof. Storing chemical fluids 10 within a
confmed storage
tank 4 may create an explosive environment. For example, chemical fluid 10 may
vaporize and
remain trapped within storage tank 4 and storage tank roof 8. This may lead to
the possibility of
explosion and/or loss of chemical fluid 10. To prevent the loss of chemical
fluid 10 and an
explosive environment, a floating roof system 2 may be placed within storage
tank 4. Floating
roof system 2 may comprise a floating roof 14 and a support 12. To prevent
evaporation of
chemical fluid 10, floating roof 14 may be disposed upon, and/or float, upon
chemical fluid 10.
Contact between floating roof 14 and chernical fluid 10 may prevent chemical
fluid 10 from
vaporizing.
[0034] In embodiments, floating roof 14 may flot be sufficiently buoyant to
float upon
chemical fluid 10. To prevent floating roof 14 from sinking, floating roof 14
may be supported by
support 12 and/or a plurality of supports 12 from storage tank roof 8. In
embodiments, supports
12 may attach to tank roof 8 by any suitable means. Suitable means may be, but
are flot limited to
nuts and bolts, pulleys, welding, and/or any combination thereof.
Additionally, supports 12 may
be disposed within storage tank roof 8 at any suitable location as to support
floating roof 14. A
suitable location may be about the center of storage tank roof 8, about the
edges of storage tank
roof 8, or between the center and edges of storage tank roof 8. Supports 12
may be any suitable
chain, wire rope, or other suitable device which may be able to support the
weight of floating roof
14. Supports 12 may attach to floating roof 14 through attachment points 30,
described below.
Additionally, bottom supports, flot illustrated, may be positioned below
floating roof 14 for
support. These bottom supports may be beams, cylindrical legs, and/or columns
within storage
tank 4. In embodiments, bottom supports may attach to floating roof 14 by any
suitable means.
Suitable means may be, but are not limited to, welding, nuts and bolts,
adhesive, and/or any
combination thereof. Bottom supports may be disposed at any suitable location
along floating
roof 14. A suitable location may be about center, about the edges of the
floating roof, and/or
between center and the edge of floating roof 14. Both supports 12 and/or
bottom supports may
be used to support floating roof 14 in the absence of chemical nid 10.
[0035] Floating roof 14 may comprise a plurality of attached pontoons 16.
Pontoons 16
may be comprised of any suitable material for floating on chemical fluid 10.
Suitable material may
- 4 -
CA 02929339 2016-05-09
be, but is flot limited to, stainless steel, aluminum, steel, black iron,
fiberglass, high-density
polyethylene (HDPE), and/or any combination thereof In embodiments, pontoons
16 may be
four sided and may further comprise any suitable shape. A suitable shape may
be, but is flot
limited to, square, rectangular, polyhedral, and/or any combination thereof.
As illustrated in
Figure 2, pontoons 16 may comprise a lower panel 18, outer walls 20,
stiffeners 22, upper panel
24, and panel clips 26. Lower panel 18 may comprise any suitable shape. A
suitable shape may
be, but is flot limited to, square, rectangular, polyhedral, and/or any
combination thereof. In
embodiments, lower panel 18 may have a length and/or width of about two feet
to about twenty
feet, about five feet to about fifteen feet, about ten feet to about eighteen
feet, or about six feet to
about twelve feet. Lower panel 18 may comprise a single sheet of material and
may form a
structure in which outer walls 20, stiffeners 22, upper panel 24, and panel
clips 26 may be
disposed.
[0036] As illustrated in Figures 2 and 3, outer walls 20 may be disposed at
the edges of
lower panel 18. Outer walls 20 may comprise any suitable shape. A suitable
shape may be, but is
flot limited to, square, rectangular, polyhedral, and/or any combination
thereof. In embodiments,
outer walls 20 may have a height of about two inches to about twelve inches,
about four inches to
about eight inches, or about six inches to about ten inches. Outer walls 20
may be welded to the
edges of lower panel 18 and/or welded to adjacent outer walls 20, winch may
fon-n an open box
configuration. Additionally, as illustrated in Figure 3, the edges of lower
panel 18 may be folded,
fonned, pressed, drawn, and/or any combination thereof to form outer walls 20.
In embodiments,
fointed edges 17 may be defined as any portion of lower panel 18, outer watts
20, or their union
may be mechanically or otherwise plastically deformed in order to create a
final fabricated shape.
This may allow outer walls 20 and lower panel 18 to be comprised of the same
sheet of material,
winch may fo= a seamless edge. A seamless edge may reduce the amount of
welding that may
be required to produce a pontoon 16 and may prevent leaking between lower
panel 18 and outer
walls 20.
[0037] Referring to Figure 3, outer wall 20 may further be folded along the
edges
opposite lower panel 18, forming a ledge 19. In embodiments, ledge 19 may be
about a quarter
of an inch to about four inches long, about an inch to about three inches, or
about two inches to
about four inches. Ledge 19 may comprise any suitable shape. A suitable shape
may be, but is flot
- 5 -
CA 02929339 2016-05-09
limited to, square, rectangular, polyhedral, and/or any combination thereof.
Ledge 19 may
provide strength to outer wall 20 and may serve as a connection area for upper
panel 24. In
embodiments, ledge 19 may form a ninety degree angle with outer wall 20 or any
suitable angle
upon which upper panel 24 may attach. Mechanically bending outer wall 20 to
form ledge 19
may prevent deflection, warping, movement, bending, and/or deforrnation of
outer wall 20 and in
turn pontoon 16.
[0038] To provide additional structural support, as illustrated in Figure 2, a
stiffener 22,
and/or a plurality of stiffeners 22, may run the length and/or width of
pontoon 16. Stiffeners 22
may be disposed upon lower panel 18 and may further be disposed adjacent outer
walls 20.
Additionally, in certain embodiments, upper panel 24 may be disposed above
stiffeners 22. In
embodiments, stiffeners may be disposed from one another at any length. A
suitable length may
be about one inch to about twelve inches, about two inches to about ten
inches, about four inches
to about six inches, about six inches to about twelve inches, or about twelve
inches to about
twenty four inches. Stiffeners 22 may be forrned, pressed, machined, and/or
any combination
thereof into a "C-Channel" and/or "U-Channel." As described above, the
mechanical bend within
stiffeners 22 may strengthen stiffeners 22 and in turn strengthen lower panel
18, which may
prevent deflection, warping, deformation, and/or bending of pontoon 16.
Stiffeners 22 may attach
to lower panel 18, outer wall 20, and upper panel 24 by any suitable means.
Suitable means may
be, but are flot limited to, weld, adhesive, nuts and bolts, screws, and/or
any combination thereof.
Upper panel 24 may further be disposed above stiffeners 22, which may prevent
deflection,
warping, and/or bending of upper panel 24. Upper panel 24 may attach to ledge
19 of outer walls
20. Upper panel 24 may attach to outer walls 20 by weld, adhesive, nuts and
bolts, and/or any
combination thereof. Attachrnent of upper panel 24 to ledge 19 may seal
stiffeners 22 within
pontoon 16.
[0039] In embodiments, there may be two types of pontoons 16. Those two types
may be
an "open pontoon," which may not have an upper panel 24, and a "closed
pontoon," which may
have an upper panel 24. An open pontoon 25 is illustrated in Figure 4. As
illustrated, open
pontoon 25 may comprise a lower panel 18, outer walls 20, ledge 19, and
stiffeners 22. Open
pontoons and closed pontoons may each have characteristics suitable for
different projects. For
example, open pontoons 25 may flot trap vapor if an open pontoon 25 forms a
leak. Additionally,
- 6 -
CA 02929339 2016-05-09
open pontoons 25 may be cheaper to fabricate and may weigh less than a closed
pontoon. Closed
pontoons may foi _______________________________________________________ iii
an additional barrier against evaporation within storage tank 4, may be easier
to handle and install, may be difficult to sink, and may require lower design
loads. In
embodiments, a plurality of pontoons 16 may fonn floating roof 14. Attaching
pontoons 16
together may foini floating roof 14. The large surface area of floating roof
14 may allow for
floating roof 14 to be buoyant enough to float on chemical fluids 10.
[0040] Pontoons 16 may attach together through panel clips 26, as illustrated
in Figures 5
and 6. A plurality of panel clips 26 may be disposed along the edges of lower
panel 18 of
pontoon 16 and may further be disposed in a direction opposite outside walls
20. In
embodiments, panel clips 26 may comprise any suitable shape. A suitable shape
may be, but is flot
limited to, square, rectangular, polyhedral, and/or any combination thereof.
Panel clips 26 may
have a length of about one inch to about twelve inches, about four inches to
about eight inches,
about six inches to about twelve inches, or about two inches to about six
friches. In embodiments,
there may be any suitable nurnber of panel clips disposed on lower panel 18. A
suitable number of
panel clips 26 may be, but is flot limited to, about one to about six, about
two to about four, or
about three to about six panel clips. In embodiments, panel clips 26 on a
pontoon 16 may align
with panel clips 26 on an adjacent pontoon 16. Nuts and bolts, welding,
adhesive, and/or any
combination thereof may be used to bind adjacent panel clips 26 together.
Additionally, pontoons
16 may cormect along the edge of outer wall 20 opposite the edge in which
panel clips 26 may be
dispo sed.
[0041] As illustrated in Figure 5, connectors 28 may be used in conjunction
with panel
clips 26 to bind adjacent pontoons 16 into a floating roof 14. In embodiments,
connectors 28 may
connect the edge of outer wall 20 with ledge 19 to an adjacent pontoon 16
outer wall 20 with
ledge 19. Connectors 28 may take the form of a weld, adhesive, nuts and bolts,
and/or any
combination thereof. In embodiments, connectors 28 may bind the top of
pontoons 16 and panel
clips 26 may bind the bottom of pontoons 16. Additionally, there may be a
buffer, flot illustrated,
disposed between adjacent pontoons 16. The buffer may help prevent evaporation
of chemical
fluid 10 and may further prevent adjacent pontoons 16 from rubbing against
each other, which
may lead to excessive wear and tear. In embodiments, the buffer may be any
suitable material to
prevent wear and tear, suitable material may be rubber, plastic, neoprene,
and/or any combination
- 7 -
CA 02929339 2016-05-09
thereof. Fonning floating roof 14, pontoons 16 may further comprise attachment
points 30 to
further support floating roof 14 in an absence of chemical fluids 10 to ftoat
on.
[0042] In embodiments, attachment points 30, as illustrated in Figures 5 and
6, may be
disposed at any suitable location on pontoon 16. Specifically, attachment
points 30 may be
disposed along outer walls 20 and/or upper panel 24. In embodiments there may
be a plurality of
attachment points 30 on a single pontoon 16. In alternate embodiments,
attaclunent points 30
may be located throughout selected pontoons 16 within floating roof 14.
Attachment points 30
may be disposed along the edge at about the center, about the corner, and/or
between the center
and corner of outer walls 20. Additionally, attachment points 30 may be
disposed about the
center, about the edge, and/or between the edge and center of upper panel 24.
In embodiments,
attaclunent points 30 may attach to upper panel 24 and/or outer walls 20 by
any suitable means.
Suitable means may be nuts and bolts, adhesive, weld, and/or any combination
thereof As
illustrated, attachment points 30 may be a hook, D-Ring, take off, extrusion,
and/or any suitable
support device. Attachment points 30 may be used by supports 12 to support
floating roof 14
with storage tank roof 8, as described above, best illustrated in Figure 1.
[0043] As illustrated in Figure 7, rim 32 may be attached to an outennost
pontoon 40 and
may separate floating roof 14 from storage tank wall 6 (e.g., shown in Figure
1). Rim 32 may
comprise any suitable material. Suitable material may be, but is not limited
to, stainless steel,
aluminum, steel, black iron, and/or any combination thereof. In embodiments,
rim 32 may
comprise a channel 34. Channel 34 may be a "C-channel" and/or "U-channel" and
may further
comprise a flange 36 opposite the end of rim 32 that may be adjacent to
chemical fluid 10. Flange
36 may prevent chemical fluid 10 from splashing over and onto pontoons 16 and
outermost
pontoons 40. Additionally, rim 32 may comprise rim extensions 38. Rim
extensions 38 may
connect rim 32 to outermost pontoons 40. Specifically, rim extensions 38 may
attach to the
upper and lower edges of outer wall 20. In alternative embodiments, rim
extensions 38 may
attach to lower panel 18 and upper panel 24. Rim extensions 38 may connect to
outer wall 20,
lower panel 18, and/or upper panel 24 by any suitable connector 28. A suitable
connector 28 may
be a weld, adhesive, nuts and bolts, and/or any combination thereof. In
embodiments, not
illustrated, rim 32 may be separated from storage tank wall 6 by a spacer, not
illustrated. The
spacer may prevent rim 32 and storage tank wall 6 from contacting, which may
prevent excessive
- 8 -
CA 02929339 2016-05-09
wear and tear on rim 32 and storage tank wall 6. In embodiments, as
illustrated in Figure 8, rim
32 may mn the length of outennost pontoons 40. This may allow outermost
pontoons 40, which
may each have a rim 32, to form a single segmented rim. Individual rims 32
forming a single
segmented rim may require less welding and/or connectors 28 disposed on
outennost pontoons
40. Rims 32 may connect to adjacent rias 32 by a weld, adhesive, and/or any
combination
thereof.
[0044] Currently, the construction of floating roof system 2 may be perfonned
at the site
of storage tank 4. Pontoons 16, which may comprise floating roof 14, may
require large amounts
of welding and may be labor intensive. Pontoons 16 may be welded together and
a single rim may
be welded along the outer edge of the outermost pontoons 40 to form floating
roof 14. Current
methods of producing a floating roof 14 may be slow, expensive, and prone to
quality control
issues. A major contributing factor to expense and production time may be
welding time and the
number of welds made. A method of producing a floating roof 14 that reduces
the amount of
welding time and welds may result in reducing the amount of welding immersed
in chemical fluid
10, which may prevent pontoons 16 from leaking.
[0045] A method to reduce welding may inelude manufacturing pontoons 16 within
a
fabrication facility. As noted above, lower panel 18 and outer walls 20 may be
made of the same
sheet of material using formed edges and/or other techniques that may produce
seamless edges,
which may need to be welded. In alternative embodiments, a single sheet of
material may be cut
and folded to produce seams between adjacent outer -m'ails 20, which may
require only the
smallest of welding time and welds. Each embodiment may reduce the amount of
welding needed
to produce pontoon 16. The small amount of welding may also increase the
quality of pontoons
16 produced, as the seams that may be welded may be of a smaller length. In
embodiments, upper
panel 24 and attachment points 30 may be attached to pontoons 16, which may
occur within the
fabrication facility. Producing pontoons 16 within a manufacturing facility
may allow for larger
amounts of pontoons 16 to be produced in a shorter amount of time. A shipment
of pontoons 16
may then be sent to storage tank 4 for final assembly and installation.
[0046] Pontoons 16 may be assembled using nuts and bolts and panel clips 26.
In
embodiments a buffer may be placed between pontoons 16 before attaching
pontoons 16. Nuts
and bolts may hold pontoons 16 together, which may facilitate welding pontoons
16 to each
- 9 -
CA 02929339 2016-05-09
other. This process may be repeated any number of times to produce a floating
roof 14.
Outermost pontoons 40, may be made in the field due to their radial geometry
(in alternative
embodiments outermost pontoons may be made in a fabrication facility), winch
may allow the
outermost pontoons 40 to be disposed adjacent storage tank wall 6. Currently,
the outermost
pontoons 40 may be welded to a single and/or a small number of rims 32, winch
may overlap
adjacent outermost pontoons 40. This may cause welding problems due to the
geometry and
leng-th of the welds. As illustrated in Figure 8, to lessen the amount of
welding required, each
outermost pontoon 40 may have a separate rim 32 attached to outermost pontoons
40. Adjacent
rims 32 may be welded together with shorter welding lengths. Shorter welds may
increase quality
and reduce the amount of welding ti_me. This method of producing a floating
roof 14 may be
more efficient than previous rnethods and reduce cost and production time.
[0047] The foregoing figures and discussion are flot intended to include ail
features of the
present techniques to accommodate a buyer or seller, or to describe the
system, nor is such
figures and discussion limiting but exemplary and in the spirit of the present
techniques.
- 10-
