Note: Descriptions are shown in the official language in which they were submitted.
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TANK FORMED FROM PANELS OF COMPOSITE MATERIAL
This invention relates to a tank formed from one or more panels of a
composite material.
This application relates to the panel disclosed and claimed in Canadian
application 2,639,673 filed October 22nd, 2008. The panel used herein can be
of
the type disclosed in the above application or other composite panels can be
used.
BACKGROUND OF THE INVENTION
A panels of the above application provide an effective very strong
construction with significantly greater rigidity against bending than previous
composite panels.
This has allowed the manufacture of tanks from the panels which can
accommodate the high forces arising from contained liquids within the tank.
This construction can provide a tank of very large dimensions such as
120 feet x 40 feet x 8 feet for containing a very large body of water for
example as a
tank used for hydraulic fracturing of natural gas wells, generally known as
"frac
tanks". The advantage of using the composite panels is that they provide a
high
level of insulation to the tank which avoids or reduces heating costs to
prevent
freezing of the water in cold climates. The insulation can be supplemented by
floating further panels on the surface.
SUMMARY OF THE INVENTION
It is one object of the invention to provide a tank manufactured from
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composite panels.
According to one aspect of the invention there is provided a tank for
containing a liquid comprising:
at least one elongate tank wall;
the tank wall being formed by a plurality of wall panels arranged end to
end along the tank wall;
each wall panel being formed of a composite material including inner
and outer sheets and an intermediate core;
a metal frame for holding the panels in the tank wall including:
a base member extending along the wall at the bottom of the
panels;
and a plurality of joining members connected to the base
member and upstanding therefrom for holding the ends of the panels in end to
end
relationship;
and a liner on an inside surface of the panels to hold a liquid contained
by the wall.
Preferably there is provided a tension member extending along the
tank wall applying a longitudinal tension to the panels to hold them end to
end.
Preferably the tension member such as a cable is arranged closely
adjacent and outwardly of the base member.
Preferably the tank includes at least two planar walls each formed from
a plurality of planar panels where the two walls are connected at a corner.
However
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cylindrical tanks using curved panels can also be manufactured using this
process.
Preferably there is provided a corner post having two channel
members each having a base and two sides for receiving an edge of an end one
of
the panels of the respective wall and wherein one channel is offset along its
wall
from the other to expose a part of the base of the other channel.
Preferably there is provided at the corner post a bracket member for
holding two tension members each extending along a respective one of the walls
and wherein the bracket member includes respective portions thereof butting
the
bases of the channels to apply force thereto.
Preferably there are provided inclined support braces at spaced
positions along the wall and each associated with a respective one of the
joining
members.
Preferably the panels are unsupported by the frame along the top edge
of the panels.
Preferably there is provided a plurality of upstanding posts at spaced
positions along the wall and exterior to the wall post with a bottom of each
post
connected to the base member.
Preferably the posts are attached to a top wall engagement member
for locating the post at the top edge of the wall and wherein there is
provided a
longitudinal tension member which extends from the post over the top edge of
the
panel at right angles to the wall for engaging a spaced parallel wall of the
tank.
Preferably the top wall engagement member comprises an inverted
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channel and a receiving member for engaging and locating the post.
Preferably there is provided a plurality of parallel base panels arranged
to lie on a ground surface inside said at least one wall with an edge of each
panel at
the base member of the wall.
Preferably the base member includes a channel for receiving end
edges of the base panels.
Preferably the parallel base panels are connected side edge to side
edge by connecting members at spaced positions along the side edges.
Preferably there is provided at each joining member a connecting
member extending transverse to the wall from a position outside the wall to a
position inside the wall and connecting the side edges of the base panel
inside the
wall and including a brace extending from the connecting member outside the
wall to
the wall to hold the wall at right angles to the connecting member.
Preferably the tank comprises four walls arranged in a rectangular
arrangement of a first pair of parallel walls and a second pair of parallel
walls
connected at four corners and wherein there is provided a plurality of
parallel base
panels lying on the ground.
In this arrangement, preferably the base panels span across between
the first pair of walls so as to have end edges of the base panels arranged at
each of
the first pair.
In this arrangement, preferably each of the walls has at spaced
positions therealong a plurality of posts mounted outside the walls and each
having
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a top wall engagement member for locating the post at the top edge of the wall
and
wherein there is provided a longitudinal tension member which extends from the
post over the top edge of the panel at right angles to the wall for engaging a
corresponding post of the spaced parallel wall of the respective pair.
5 In this arrangement, preferably the second pair of walls are formed
from a single panel extending along the full length of the wall and the first
pair of
walls includes a plurality of panels arranged end to end.
In this arrangement, preferably the base panels are connected edge to
edge by edge connecting members at spaced position therealong where the
connecting members are arranged so as to be located at positions aligned with
the
tension members spanning the second pair of walls.
Preferably the panel member is of the above type comprising a
honeycomb core panel having a first face and a second opposite face with an
array
of generally hexagonal tubular cells defined by walls of the core panel
extending
between the first and second faces;
a foam material filling the tubular cells;
a first fibrous reinforcing cover sheet extending over the first face of the
core panel;
a second fibrous reinforcing cover sheet extending over the second
face of the core panel;
the first and second cover sheets being filled with a set resin material;
wherein the walls of the honey comb core panel are formed from a
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porous fibrous material;
and wherein the set resin in the cover sheets extends from the cover
sheets into the porous fibrous material of the walls of the core panel so as
to form an
integral structure of the resin extending between the walls and the sheets.
In one arrangement the tank may be rectangular. In this case the tank
is formed from a plurality of panels arranged edge to edge.
The panel members can be connected edge to edge by an adhesive or
by channel members into which an edge of the panel is inserted.
In another arrangement the tank may have a cylindrical wall and at
least one circular end wall.
In this case the circular end wall can be formed of a single panel
member and the cylindrical wall is formed of one or more curved panel members.
Thus the cylindrical wall can be formed of a single peripheral panel
member with the first cover sheet defining an inner surface of the tank and
the
second cover sheet defining an outer surface of the tank.
Preferably the walls of the honey comb core panel are formed from a
porous fibrous material and the set resin in the cover sheets extends from the
cover
sheets into the porous fibrous material of the walls of the core panel so as
to form an
integral structure of the resin extending between the walls and the sheets.
Preferably the resin substantially fills the material of the core walls and
preferably the resin extends through the core walls from the first sheet to
the second
sheet. However the first intention is that the resin acts firstly to form an
integral
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connection between the layer defined by the face sheets and the core walls so
as to
provide and increased resistance to shear forces tending to delaminate the
structure
at the junction between the sheet and the core. Hence, it will be appreciated
that, in
order to achieve this requirement, the resin may not extend fully through the
structure to form the tubular reinforcement. Thus other resins can be used in
the
core material provided they do not interfere with the formation of the
integral
connection.
Secondly the intention is that the resin forms an increased
compression resistance in the core panel by forming a series of resin
reinforced
tubes through the panel at the walls. Hence, it will be appreciated that, in
order to
achieve this requirement, the resin may not extend fully into each and every
pore or
space in the walls but the resin will extend into the structure sufficiently
to form the
integral connection at the sheets and the tubular reinforcement extending
through
the panel.
It will be appreciated that the walls generally do not contain any
existing resin filling material when the resin introduction occurs since this
will prevent
or inhibit the penetration of the resin into the walls and the formation of
the tubular
structures through the panel and the integral connection to the sheets.
However the
walls may contain some reinforcing resin provided it does not prevent the
formation
of the integral connection.
Preferably the resin is a thermosetting resin such as thermosetting
polyester. However other types of resin can be used such as polyurethane or
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epoxy, vinyl ester, phenolic resin.
Preferably the walls are connected each to the next to form the
honeycomb panel by a heat seal. This is preferred as the heat seals are less
likely
to interfere with the entry of the resin during the resin introduction process
and are
easier to effect and less expensive. However adhesive connection may be used.
Preferably the walls are formed from a non-woven fibrous material
such as a spun bond fibrous plastics material. However the material selected
can
be of any construction provided it is porous so as to allow the penetration of
the
resin during the resin introduction step. Thus of course aluminum and plastics
film
cannot be used. The material should also bond to the foam during the foam
filling
step. The compressive strength of the material in the honeycomb construction
is of
less importance and can be quite low in comparison with other. materials, such
as
those conventionally used, provided it is sufficient to allow the foam filling
step to
occur.
Preferably the sheets contain glass reinforcing fibers as these are
inexpensive and are known to provide the required strength characteristics.
However other reinforcing fibers can be used.
While the term "honeycomb" is used generally and in this document it
will be appreciated that the tubular cells formed are generally not accurately
hexagonal in cross section, particularly where, as described herein, the cells
are
formed from a porous fibrous material without reinforcing resin available
during the
filling process to maintain a regular shape of the cells.
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The manufacture of panels in the manner set forth above allows the
formation of panels which can be as much as 8 feet x 40 feet and either 3
inches or
6 inches thick for different levels of insulation. In this way a tank can be
manufactured using the panels with a width formed by one panel of 40 feet and
a
length formed by several panels arranged end to end. Base panels of the same
length can be used to cover the ground with each panels spanning across the
width.
BRIEF DESCRIPTION OF THE DRAWINGS
One embodiment of the invention will now be described in conjunction
with the accompanying drawings in which:
Figure 1 is horizontal cross sectional view through a panel to be used
in the present invention.
Figure 2 is a vertical cross sectional view through the panel of Figure
1.
Figure 3 is an isometric view of a tank according to the present
invention.
Figure 4 is a top plan view of the tank of Figure 3.
Figure 5 is a side elevational view of the tank of Figure 3.
Figure 6 is an isometric view of one corner post of the tank of Figure 3.
Figure 7 is a cross-sectional view along the lines 7-7 of Figure 6 of the
tank of Figure 3.
Figure '8 is an isometric view of one joining member between two
panels of the wall of the tank of Figure 3.
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Figure 9 is a cross-sectional view along the lines 9-9 of Figure 8 of the
tank of Figure 3.
Figure 10 is an isomeric view of the bottom end of one post of the wall
of the tank of Figure 3.
5 Figure 11 is an isometric view of the top end of one post of the wall of
the tank of Figure 3.
Figure 12 is a cross-sectional view along the lines 12-12 of Figure 8 of
the tank of Figure 3.
Figure 13 is a cross-sectional view along the lines 13-13 of the tank of
10 Figure 3.
DETAILED DESCRIPTION
The composite panel described in general above is shown in Figure 1
and 2 and is formed by a honeycomb core panel 10 having a first face 11 and a
second opposite face 12 with an array of generally hexagonal tubular cells
defined
by walls 10A of the core panel extending between the first and second faces.
The
cells are formed from strips 15, 16 arranged side by side of a porous fibrous
material
which is heat sealed at a sealing line 14 to define the generally hexagonal
cells.
A foam material such as a polyurethane foam 18 fills the tubular cells.
A first fibrous reinforcing cover sheet such as a fiberglass mat (or
carbon fiber, aramid fiber, Kevlar fiber, polyester fiber, natural fiber -
e.g. hemp, flax,
straw) 19 extends over the first face 11 of the core panel and a second
fibrous
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reinforcing cover sheet 20 extends over the second face of the core panel.
The first and second cover sheets are filled with a set resin material 21
which extends from the cover sheets 19, 20 into the porous fibrous material of
the
walls 15, 16 of the core panel so as to form an integral structure of the
resin
extending between the walls and the sheets.
In Figure 3 is shown a tank 10 which is rectangular and is formed from
a plurality of panels 11 to 13. The tank 10 is formed from two pairs of
parallel walls
14, 15 and 16, 17 connected at four corners to form a rectangular tank. The
walls
14, 15 are formed by single panels 11 spanning the full length of the wall.
The walls
16, 17 are formed by a plurality of panels 12 arranged end to end along the
wall.
The tank is completed by base panels 13 lying on the ground which also span
the
space between the walls 16 and 17 so that the panels 13 have end edges 13A at
the
walls 16 and 17.
Thus the tank walls 15, 16 are formed by a plurality of wall panels 12
arranged end to end along the tank wall. Each wall panel 11, 12, 13 is formed
of a
composite material including inner and outer sheets and an intermediate core
as
previously described.
There is also provided a metal frame for holding the panels together to
form the construction of the tank and particularly each tank wall. The frame
structure includes a base member 18 extending along the wall at the bottom of
the
panels, and a plurality of joining members 19 connected to the base member and
upstanding therefrom for holding the ends of the panels in end to end
relationship.
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In order to hold liquid, particularly water, without escaping between the
panels and
the frame there is provided a conventional liner schematically indicated at 20
on an
inside surface of the base panels and up the wall panels over a top edge of
the wall
panels to hold a liquid contained by the wall.
The frame further includes a plurality of corner members 23 each
arranged at a respective corner between two walls.
The base panels 13 are connected and held edge to edge by grade
beam elements 21 which are H-shaped in cross-section as shown in Figure 13 to
receive in the two channels thus defined the edges of the adjacent panels 13.
The
grade beam elements include outer portions 21A and 21B at the walls 16 and 17
together with intermediate portions 21C and 21D. The portions 21C and 21D are
located at each space between two adjacent panels whereas the portions 21A and
21 B are located only at the joining members 19.
Each wall is associated with a plurality of posts 22 at spaced positions
along the length of the wall. Thus the walls 14 and 15 have only two posts
spaced
from one another and from the corner members 23. Thus each wall 16 and 17 has
a
series of posts with each panel having two posts making a total of eight posts
for the
four panels with again the posts being spaced from one another and from the
corner
members 23 and from the joining members 19.
Each wall has provided a tension member or cable 24 extending along
the tank wall at the base of the posts 22 and closely adjacent the base member
18
applying a longitudinal tension to the panels to hold them end to end.
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Also each post 22 corresponds in position to an associated post at the
opposite wall and a tension member or cable 25 spans across the tank between
the
two associated posts to apply a tension across the tank. As best shown in
Figures 8
and 9, the tension member or cable 24 is arranged closely adjacent and
outwardly of
the base member 18 and extends past each joining member 189 along the full
length of the wall for connection to the respective corner members 23.
As shown best in Figures 6 and 7, each corner post 23 has two
channel members 23A and 23B each having a base 23C and two sides 23D for
receiving an edge of an end one of the panels of the respective wall and
wherein
one channel 23B is offset along its wall from the other 23A to expose a part
of the
base 23C of the other channel 23A. This allows at the corner post 23 a bracket
member 23E to be connected for holding two tension members 24 each extending
along a respective one of the walls 17, 15. This shaping of the corner member
23
allows wherein the bracket member 23E to include respective portions 23F and
23G
thereof butting the bases 23C of the channels 23A and 23B to apply force
thereto in
the direction along the wall.
As best shown in Figures 3 and 8, there are provided inclined support
braces 26 at spaced positions along the walls 16 and 17 and each associated
with a
respective one of the joining members 19. At each joining member 19 there is
provided a connecting member 19A extending transverse to the wall 17 from a
position 19B outside the wall to a position 19C inside the wall where it forms
the
grade beam 21A. As previously stated, the beam 21A acts to connect the side
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edges of the base panel inside the wall. The connecting member 19A is thus a
rigid
structure extending under the wall from the outer portion 19B into the grade
beam
21A as an integral member to provide stability to the wall against tilting and
lifting.
The outer portion 19B is connected to the brace 26 extending from the
connecting
member 19A outside the wall to the wall at the joining member 19 to hold the
wall at
right angles to the connecting member.
The cylindrical posts are best shown in Figures 10 and 11 and are
located at spaced positions along the wall and exterior to the wall. A bottom
end
22A of each post is connected to the base member 18 by a circular collar 22B
attached at one side 22C to the outer wall of the rail forming the base member
18.
This holds the post fixed to the rail 18. The cable 24 extends through a hole
24A at
the bottom of the post so as to be located by the posts along the outside of
the wall
to prevent distortion of the cables away form the wall.
As shown in Figure 11, the upper end 22D the posts are attached to a
top wall engagement member 22G for locating the post at the top edge of the
wall.
The top wall engagement member 22G comprises an inverted channel 22H which
sits over the top edge of the panel and a receiving collar 22E for engaging
and
locating the upper end 22D of the post 22. The collar is welded to one side of
the
channel 22H so that the collar is held against movement relative to the top
edge of
the panel. A longitudinal tension member 25 extends through a hole 25A in the
post
and is held there by a screw coupling 25B. The cable 25 therefore extends from
the
post 22 over the top edge of the panel over the channel 22H in a direction at
right
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angles to the wall for engaging the associated post at the opposite spaced
parallel
wall of the tank.
As shown in Figure 4, the cables 24 extending longitudinally along the
tank between the walls 14 and 15 and parallel to the walls 16 and 17 are
positioned
5 on the posts so that the connecting members 21A are arranged so as to be
located
at positions aligned with the cable. This ensures that the teOnsion applied by
the
cables is applied onto the structure at a position where the base panels are
held
against relative movement by the connecting members 21A.
The wall panels are unsupported by the frame along the top edge of
10 the panels so that there is no requirement for any structural connections
at this
location. The channels 22G (Figure 11) are sufficient to communicate forces
from
the cables 25 and the posts 22 to the top of the wall and also to act as hold
down
members for the top edge of the liner which extends over the top of the wall
and
drapes down the outside surface of the wall panels to a length sufficient to
prevent
15 the liner from being pulled out.
