Note: Descriptions are shown in the official language in which they were submitted.
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A FORM FOR CONTAINING SETTABLE FILLER MATERIAL DURING SETTING
This invention relates to a form for containing and shaping a settable
filler material during setting of the material and particularly with forming a
pumped
high strength grout or concrete type material into a column shape and holding
the
material while it sets. The material with which the present invention is
primarily but
not exclusively concerned is that used for creating high strength
reinforcement
columns in a mine shaft to prevent collapse of the shaft.
BACKGROUND OF THE INVENTION
Fabric bags are used for containing many bulk materials. Some bags
are used for transporting particulate materials. Such bags are commonly formed
by
stitching woven polypropylene fabric to forms walls of the container and in
many
cases a liner is provided.
Fabric containers are often used also for containing fill material to form
a geo-textile container which holds the fill material in location.
One example of a geo-textile container is shown in US patent
5,902,070 of Bradley Industrial Textiles Inc. This comprises a tubular body
which
may typically be 2000 feet in length and may typically be up to 45 feet in
diameter.
Such a tubular body is used to contain fill and is located in a bay to reduce
erosion.
The use of a strip of material which is wound helically to form a tube is
previously known and is used in a number of different circumstances for
forming a
tubular cover. The above patent utilizes this known technique for
manufacturing a
geo-textile tube which includes the helically formed tube together with a
liner. These
techniques, it is stated, overcome the weakness of the seam.
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In an entirely unrelated field, forms are used to manufacture concrete
columns. In many cases the form is a tubular cardboard or paper structure
which
contains the concrete for a sufficient period of time for it to set. In cases
where the
column is of too large a diameter or where the structure is more complex, the
form
work necessary to support the concrete material while it sets is generally
fabricated
from wooden panels and suitable supporting framework.
It will of course be appreciated that a large diameter column of a
significant height generates very high pressures at the lower part of the
column thus
tending to burst or expand containing materials. For this reason cardboard or
paper
products are completely unsuitable for containing columns having a diameter
greater
than of the order of 18 inches.
One field where trials have recently been carried out is that of
providing reinforcing columns within a mine shaft to provide sufficient
strength to
support the roof of the mine shaft against collapse after the mine shaft is
abandoned. Such columns must provide very high strength and of course must be
cast in place to provide a complete support between the floor and roof of the
shaft.
For this purpose conventional concrete is generally unsuitable and it has been
necessary to generate new high strength settable filler materials or grout
which can
provide, generally without steel or other reinforcements, the necessary
strength to
provide support for the mine shaft without the necessity of filling the whole
shaft
across its full area or volume.
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Such filler materials which are suitable for this purpose generally are
pumped in a hot fluid condition. Up until now the only suitable technique to
contain
the fluid materials in their heated condition until set has been to provide
the
conventional panelling and framework. However it will be appreciated that this
construction is highly labour intensive and therefore very expensive.
Some trials have been carried out for the use of fabric bags to contain
the hot fluid grout material until set. However these fabric bags have
generally failed
in trials due to the high forces at the bottom of the tubular bag which tend
to bow or
expand the bag at that area thus allowing the filler material to slump so that
it fails to
provide its proper shape and construction. Also the heat of the fluid material
exacerbates the tendency of the fabric bags to expand. The failure of the bags
has
therefore not been at the seams but has instead been over the body of the
fabric
material itself which has simply expanded sufficiently to fail in its
requirement to
maintain the required cylindrical shape.
SUMMARY OF THE INVENTION
It is one object of the present invention, therefore, to provide an
improved form construction for containing and shaping a settable filler
material
during setting of the material.
According to a first aspect of the invention, therefore, there is provided
a form for receiving and containing a settable filler material while the
material sets
comprising:
a tubular wall;
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two circular end panels;
the wall and end panels each being formed from a flexible woven
polymer fabric;
each of the panels being stitched around its circular peripheral edge to
an end edge of the tubular wall;
at least one filler opening into the form for receiving the filler material;
wherein the tubular wall is formed from a strip of the fabric which is
arranged helically such that one side edge of the strip is stitched to an
opposed side
edge of a next turn of the strip to define a stitched seam which extends
helically
around the tubular wall from one end panel to the opposite end panel.
The fabric is flexible such that the form can generally be folded flat for
transportation and storage and for location within confined areas.
Preferably the flexible woven fabric is laminated on its inside surface
with a metal foil layer.
Preferably the strip of fabric has a width relative to the diameter of the
tubular wall such that the strip extends in at least one turn of helix and
such that
preferably the strip lies at an angle of the order of 45 degrees relative to a
line
transverse to the longitudinal axis of the tubular member.
Preferably there is provided a filler opening in one end panel and a
filler opening in the tubular wall, although in some cases only a single
filler can be
provided. Such a filler opening includes preferably a closing spout using a
tie
closure or the like of a conventional nature well known to one skilled in the
art.
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Preferably there are provided support straps adjacent the one end
panel which has the filler opening.
Preferably the tubular wall and the end panels each consist of single
layer of the fabric.
5 Preferably the tubular wall and the end panels are stitched together
with stitched seams on an outside of the form where the seams are preferably
simple overlapping seams.
Preferably the flexible fabric is pc~iypropylene woven fabric, which is
convenient, relatively inexpensive and readily available. However other
materials
may be used in special circumstances where additional expense may be
warranted.
Preferably the flexible woven fabric is of a transportation bag grade
and thus is substantially imperforate as opposed to geo-textile materials
which tend
in most cases to be perforated to allow water flow through the material while
retaining fill material within the container formed by the material.
According to a second aspect of the invention there is provided a form
for receiving and containing a settable filler material while the material
sets
comprising:
a tubular wall;
two circular end panels;
the wall and end panels each being formed from a flexible woven
polymer fabric;
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each of the panels being stitched around its circular peripheral edge to
an end edge of the tubular wall;
at least one filler opening into the form for receiving the filler material;
wherein the flexible woven fabric is laminated on its inside surface with
a metal foil layer.
According to a third aspect of the invention there is provided a method
for forming a support column comprising:
providing a form for receiving and containing a settable filler material,
the form comprising:
a tubular wall;
two circular end panels;
the wall and end panels each being formed from a flexible woven
polymer fabric;
each of the panels being stitched around its circular peripheral edge to
an end edge of the tubular wall;
at least one filler opening into the form for receiving the filler material;
locating the form with one end panel uppermost at a surface to be
supported and with the opposite end panel resting on a floor surface;
pouring into the form a heated settable filler material;
and causing the filler material to set while contained by the form;
wherein the flexible woven fabric is laminated on its inside surface with
a metal foil layer.
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According to a fourth aspect of the invention there is provided a
method for forming a support column comprising:
providing a form for receiving and containing a settable filler material,
the form comprising:
a tubular wall;
two circular end panels;
the wall and end panels each being formed from a flexible woven
polymer fabric;
each of the panels being stitched around its circular peripheral edge to
an end edge of the tubular wall;
at least one filler opening into the form for receiving the filler material;
locating the form with one end panel uppermost at a surface to be
supported and with the opposite end panel resting on a floor surface;
pouring into the form a heated settable filler material;
and causing the filler material to set while contained by the form;
wherein the tubular wall is formed from a strip of the fabric which is
arranged helically such that one side edge of the strip is stitched to an
opposed side
edge of a next turn of the strip to define a stitched seam which extends
helically of
the tubular wall from one end panel to the opposite end panel.
BRIEF DESCRIPTION OF THE DRAWINGS
One possible embodiment of the invention will now be described in
conjunction with the accompanying drawings, in which:
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Figure 1 is an isometric view of a form according to the present
invention when expanded from a folded condition ready to receive the settable
material.
Figure 2 is a cross sectional view through the form of Figure 1 showing
it in the installed condition with the settable material contained therein and
setting to
form a reinforcement column.
Figure 3 is a cross sectional view through one seam of the form of
Figure 1 showing the construction of the seam and the fabric from which the
form is
manufactured
DETAILED DESCRIPTION
In Figure 1 is shown a form 10 which is defined by a top circular panel
11, a bottom circular panel 12 and a tubular wall 13. The tubular wall 13 is
formed
from a strip 14 of fabric which is wound helically to for a series of turns of
the strip
which are indicated at 14A, 14B and 14C along the length of the tubular wall
13.
Thus one side edge 15 of the turn 14B is stitched to a second side edge 16 of
the
turn 14C. Thus the side edge 16 of the turn 14B is stitched to the side edge
15 of
the turn 14A.
In practice the strip can have a long length from a suitable rolled
supply and can be formed continuously into a continuous helical tube having
the
required diameter of the tubular wail 13. From the continuous tubular body,
sections
can be cut in transverse direction to the axis of the tubular body thus
cutting the strip
diagonally so that each of the turns 14A and 14C has a diagonal transverse cut
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forming a bottom end 17 of the tubular wall and a top end 18 of the tubular
wall. In
practice the material can be folded flat for cutting since the fabric is
flexible and can
be laid flat after the stitched seams are formed.
The end panels 11 and 12 are simply flat circular panels formed from
the same fabric which are then stitched so that the peripheral outer edge 19
of the
panel 11 is stitched around the top edge 18 of the tubular wall and the
peripheral
edge 20 of the panel 12 is stitched around the bottom edge 17 of the tubular
wall.
The seams are formed on the outside of the structure for convenience of
manufacture since the appearance of the product is of little or no importance
and the
product will not be in view once it has been used to provide the form for the
material
since the installation is in almost all cases at a location where neither the
column nor
the exterior form work will be visible.
The exterior seams are shown in one example in Figure 3 where the
helical seam between the edges 15 and 16 of the turns 14A and 14B is shown.
Thus the edges are simply turned outwards to form overlying flanges which are
then
stitched together by one or more rows of stitches along the seam as indicated
at 25.
In examples shown there are two rows of stitches shown at 25 and 26 side by
side.
Other forms of stitching can be used to provide seams of increased strength
but
generally this is not necessary since a simple overlapping seam can be used as
the
strength of the seam is not seriously tested in the construction herein.
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The fabric from which the side wall and the panels are manufactured is
also shown in Figure 3 and is a laminated fabric including an outer layer 30
and an
inner layer 31.
The outer layer 30 is a woven polypropylene fabric having the following
5 typical characteristics.
The layer 31 is a metal foil layer laminated onto the inside surface of
the woven fabric layer. The woven fabric layer is free from coatings so that
it
consists solely of the woven yarns and the foil layer is laminated onto the
inside
surface of the fabric by a suitable adhesive material. The foil is preferably
of a
10 thickness so that it is highly flexible with the flexing of the fabric.
Aluminium foil is
suitable in view of its cost, handling and flexibility.
The forms typically have a diameter of the order of 2 to 5 feet and one
example is of the order of 3 feet in diameter which has been certain to
provide the
necessary structural strength for the fabricated column. The height of the
tubular
wall is typically in the range 6 to 8 feet which is sufficient to provide a
structural
support between the ceiling and floor of the mine shaft. Larger forms can also
be
used both in diameter and in heights for larger mine shafts.
The width of the fabric strip 14 is selected relative to the diameter of
the tubular wall so that the seams extend diagonally relative to a line
transverse to
the longitudinal axis of the tubular wall which angle is indicated at A which
lies of the
order of 45°. This angle can be varied within a range which can be
selected by one
skilled in the art bearing in mind that a smaller angle to the transverse line
that is a
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larger angle to the longitudinal axis will act to increase the number of turns
around
the axis which will assist in maintaining the form at the bottom of the bag
where the
forces are greatest and increase strength characteristics. However the limits
on the
angle arise due to an increased difficulty in manufacture so that the
selection of
angle is based upon a balance of increased strength relative to manufacturing
difficulty..
The construction set forth above also lays the fabric on the bias
relative to the axis of the tubular wall.
The use of the diagonal wall structure has been found to reduce the
expansion of the fabric at the lower part which can cause slumping of the
contained
filler material. The use of the foil laminated liner on the inside surface of
the fabric
has also been found to reduce the expansion of the fabric when containing the
heated filler material. The two features in combination are preferably used
since in
combination they provide the best arrangement for reducing the tendency of the
fabric of the tubular wall from distorting from its normally cylindrical
shape. It is
believed that the bias arrangement of the fabric together with the heat
dissipating
characteristics of the liner tend to reduce the possibility for the fabric to
soften and
expand particularly at the areas of highest pressure.
In order to fill the form with the settable heated filler material, a first
filler opening 40 is provided in the top panel 11 and the second filler
opening 41 is
provided in the side wall at a position approximately mid-height of the side
wall.
These filler openings are of the type having an neck 43 into which the filler
material
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can be injected by wrapping the neck around a filling pipe. The neck can be
tied off
by a suitable wrapping 44 which then closes the neck to prevent the filler
material
from gushing or escaping from the form, bearing in mind that the filler
material is
generally under pressure within the form and is sufficiently liquid to flow
into the form
and to fill all voids within the form.
In order to support the form within the zone to be filled, there is
provided a pair of support straps 50 on the side wall adjacent the top end
panel 11.
The straps 50 are provided on the side wall just downwardly from the panel so
that
the panel can be located at the ceiling while the straps are held on suitable
connectors attached to the ceiling on each side of the tubular wall.
Additional straps
can be provided for additional support.
The form of the above construction has been found to provide
sufficient support for the heated filler material for a sufficient period of
time to allow
the filler material to set in the required position without slumping during
the setting.
While the fabric is impermeable in view of the laminated foil layer, there is
sufficient
openings at the stitch lines to allow excess water to escape if necessary.
When the material is set, the form can simply remain in place since in
most cases its presence is irrelevant to the function thus avoiding the
necessity for
its removal.
Since various modifications can be made in my invention as herein
above described, and many apparently widely different embodiments of same made
within the spirit and scope of the claims without departing from such spirit
and
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scope, it is intended that all matter contained in the accompanying
specification shall
be interpreted as illustrative only and not in a limiting sense.
