Note: Descriptions are shown in the official language in which they were submitted.
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FOAM DELIVERY SYSTEM
BACKGROUND
[0001] This patent document relates to a system to deliver two-part expanding
polymeric
resins to below surface depths.
[0002] In a typical two-part expanding polymeric resin system, the two
chemical
components are impingement-mixed at the surface through appropriate
pumping/proportioner
equipment and delivered through a single injection tube or probe. The depth to
which the
mixed components can be delivered is limited to: (a) the time it takes the
mixed components
to gel and "set-up" which is a function of the density/mix of the resin system
and the
temperature the resin is injected; (b) the back-pressure created at the end of
the probe due to
the expansion of the resin after it is injected; (c) if air-locks within the
delivery probe occur;
and (d) the pressures the mixed material can be injected through a single
probe.
[0003] The gel time of typical two-part expanding resin systems is generally
very short
and usually measured in seconds. The more reactive or faster is the expansion
of the resin
system, the quicker the gel time or set-up time. Similarly, within limits, as
the temperature of
the chemicals increase, the gel time or set-up time decreases. The gel time or
set-up time often
limits the depths to which an already-mixed polymeric resin system can be
delivered before
the material "sets up" and plugs the injection probe.
[0004] Once the mixed expanding resin is injected through the injection probe,
a back-
pressure often develops around the base of the area of the injection and the
back-pressure
slows down the rate of injection of the mixed resin, which causes the resin to
prematurely set-
up in the injection probe and plugs the probe.
[0005] If the soils at depth into which the expanding resin system is being
injected into are
very cohesive or saturated, the air within the injection probe could create an
air-lock as the
chemicals are being delivered from the surface through a single injection
probe. At the very
least, the back pressure caused by the air within the injection probe will
slow the progress of
the mixed two-part resin system and therefore minimize the amount of material
that can be
injected before the expanding resin system sets-up and plugs the probe
[0006] There is a direct relationship between the pressure at which the mixed
resins are
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injected and the depth to which the resins can be delivered. The higher the
pressure the faster
the material can be delivered through a single injection probe and therefore
the deeper and the
longer the material can be delivered before the resin sets-up and plugs the
injection probe.
Despite applied pressures in delivering the two-part resin through a single
probe, eventually
the probe will plug due to depth and/or back-pressure.
SUMMARY
[0007] This patent document addresses these and other difficulties with the
prior art.
[0008] In an embodiment there is a method of delivering a polymer resin below
ground
surface. A bore that is accessible from the ground surface is created below
the ground surface.
A mixing chamber, which is a component of a foam delivery system, is lowered
into the bore.
A polymer resin is discharged from the mixing chamber of the foam delivery
system into the
bore. The mixing chamber is lifted within the bore and the polymer resin is
discharged from
the foam delivery system when the foam delivery system is lifted within the
bore.
[0009] In an embodiment there is a foam delivery system for delivering an
expanding
polymer resin below a ground surface. The foam delivery system has a first
delivery tube
having a surface end and a mixing end and a second delivery tube having a
surface end and a
mixing end. A mixing chamber is attached to the respective mixing ends of each
of the first
and second delivery tubes. A first delivery arm and a second delivery arm
provide a pathway
from and connect to the mixing chamber for discharging the expanding polymeric
resin from
the mixing chamber.
[0010] In an embodiment there is a method of delivering an expanding polymer
resin
having a first component and a second component. An injector, which comprises
a mixing
chamber, is placed at a first sub-surface location. The first component and
the second
component of the expanding polymer resin are mixed in the mixing chamber to
create a mixed
polymer resin. The mixed polymer resin is discharged from the injector at the
first sub-surface
location creating a first foam discharge. The injector is moved to a different
sub-surface
location. The first component and the second component of the expanding
polymer resin are
mixed in the mixing chamber when the injector is at the different sub-surface
location to
create the mixed polymer resin. The mixed polymer resin is discharged from the
injector at
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the different sub-surface location creating a second foam discharge, which
expands into
contact with the first foam discharge.
[0011] These and other aspects of the device and method are set out in the
claims, which
are incorporated here by reference.
BRIEF DESCRIPTION OF THE FIGURES
[00121 Embodiments will now be described with reference to the figures, in
which like
reference characters denote like elements, by way of example, and in which:
Fig. 1 is a partial section view of a foam delivery system in a screw pile;
Fig. 2 is a partial section view of a foam delivery system in a first sub-
surface
location in a bore; and
Fig. 3 is a partial section view of a foam delivery system in a second sub-
surface
location in a bore.
DETAILED DESCRIPTION
[00131 In the claims, the word "comprising" is used in its inclusive sense and
does not
exclude other elements being present. The indefinite article "a" before a
claim feature does
not exclude more than one of the feature being present. Each one of the
individual features
described here may be used in one or more embodiments and is not, by virtue
only of being
described here, to be construed as essential to all embodiments as defined by
the claims.
[0014] Figs. 1- 3 show embodiments of a foam delivery system 10. The foam
delivery
system 10 has a first delivery tube 12 and a second delivery tube 14 each
having a surface end
30 and a mixing end 32. An injector 16 comprising a mixing chamber 22 is
attached to the
respective mixing ends 32 of each of the first and second delivery tubes 12,
14. A delivery
manifold 24 comprising first and second delivery arms 52 connects to the
mixing chamber 22
and provides a pathway for discharging the expanding polymeric resin from the
mixing
chamber 22. Air bleed valves 20 connect to the mixing ends 32 of the first and
second
delivery tubes 12, 14. The air bleed valves 20 are hard fixed into each of the
first and second
delivery tubes 12, 14 thereby preventing the possibility of air locks as the
two components
Component "A" and Component "B" are pumped through the delivery tubes 12, 14
to depth.
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[0015] Figs. 2 and 3 show an embodiment of the foam delivery system 10 in
operation.
The foam delivery system 10 delivers an expanding polymer resin having a first
component
(Component "A") and a second component (Component "B") into a sub-surface
location
through the first and second delivery tubes 12 and 14, respectively. The
injector 16 is placed
at a first sub-surface location, for example the position shown in Fig. 2. The
first component
and the second component of an expanding polymer resin are transported through
the first and
second delivery tubes 12, 14 to the mixing chamber 22 to create a mixed
polymer resin 38.
The mixed polymer resin 38 is discharged from the injector 16 at the first sub-
surface location
to create a first foam discharge 40. The injector 16 is moved to a different
sub-surface
location as shown in Fig. 3. Again, the first and second components of the
expanding polymer
resin are mixed in the mixing chamber 22 when the injector 16 is at the
different sub-surface
location to create the mixed polymer resin. The mixed polymer resin is
discharged from the
injector 16 at the different sub-surface location creating a second foam
discharge 42 so that
the second foam discharge 42 expands into contact with the first foam
discharge 40 as shown
in Fig. 3.
[0016] To deliver foam below a ground surface 34 a bore 36 (Fig. 2) may be
created below
the ground surface 34 prior to operation of the foam delivery system 10. In
the embodiment of
Fig. 1, the foam delivery system 101ies within a screw pile having a drill
stem wall 18 and a
screw 28 at the base to bore into the ground. As shown in Fig. 2, the bore 36
is accessible
from the ground surface 34. In the embodiment of Fig. 2 the mixing chamber 22
is lowered
into the bore 36. A polymer resin is discharged from the mixing chamber 22 of
the foam
delivery system 10 into the bore 36. The foam mixing chamber 22 is lifted
within the bore 36.
The polymer resin is discharged from the foam delivery system 10 when the foam
delivery
system 10 is lifted within the bore 36. For example, the foam delivery system
10 may
continuously discharge the polymer resin as the foam delivery system 10 is
lifted in the bore
36.
[0017] Fig. 1 shows an embodiment in which the pile stem 44 containing the
foam
delivery system 10 is a drill stem that can be driven, screwed or drilled to
the desired depth.
Component "A" and Component "B" are independently pumped in the desired
proportions
through delivery tubes 12, 14 to the depth that the mixed polymer resin is to
be injected. The
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polymer resin is injected to the exterior of the drill stem wall 18. Below the
air bleed valves
20 are a mixing chamber 22 and delivery manifold 24 which together comprise
the injector
16, or mixing /manifold delivery module. The delivery arms 52 of the delivery
manifold 24
attach to a connecting tube 50 that attaches between a port 46 of the delivery
arm 52 and a
stem wall port 48 in the drill stem wall 18. The stem wall ports 48 in the
drill stem wall 18
may be pre-attached to the connecting tubes 50 prior to being lowered into the
ground. The air
bleed valves 20 are each appropriately-sized conventional air bleed valves and
are affixed to
each of the delivery tubes 12, 14 to evacuate air from the delivery tubes 12,
14 as the two
liquids, Components "A" and "B", are being pumped into the delivery tubes 12,
14.
[0018) Below the mixing end 32 of the delivery tubes 12, 14, the two
Components "A"
and "B" combine together in the mixing chamber 22. The mixing chamber 22
comprises off-
setting arms 26, which may be appropriately angled and spiraled to effect
maximum mixing
of the two chemicals coupled with opposing flow of the chemicals themselves.
[0019] In other embodiments, the pile stem may be a different form of hollow
pipe. For
example, the pile stem may be a drill stem or a conduit
(0020] In other embodiment other expandable synthetic substances having
similar
properties may be used. The particular resin system used can be tailored to
meet specific
design applications relating to compressive strength, tensile strength, shear
strength, flexural
strength and other structural characteristics to meet the specific design
application of the resin
system for any given project. In some embodiments, for example, the polymeric
resin system
to be delivered at depth may be a high density, two-part, closed-cell, hydro-
insensitive
polymer resin, such as a polyurethane system.
[0021] In some embodiments, the delivery tubes or probes can be made of metal
such as
aluminum, copper, steel or other metal or, made of a synthetic material such
as rigid or
flexible plastics, fiberglass or other synthetic material. The delivery tubes
12, 14 could be
sectional with each section being welded, friction fitted, glued, screwed or
joined together in
some other fashion. The embodiments of Figs. 1 to 3 show schematic designs of
the foam
delivery system 10. In other embodiments, various orientations and shapes of
the components
of the foam delivery system are possible.
[0022] In some embodiments, the delivery tubes 12 and 14 can be, for example
made of
CA 02583016 2007-03-13
rigid metal, synthetic material or flexible metal through which each of the
two component
parts of the expanding resin will be individually pumped to the desired depth.
The delivery
tubes 12 and 14, which for example, may have a'/4" - 3/4" inside diameter or
larger, may be
constructed from one continuous length or may be sectional and glued, welded,
screwed,
friction fit, or otherwise fit together to form a delivery tube of the desired
length. The
pumping system(s) may be, for example, a conventional pumping and/or
proportioner
equipment readily available in the marketplace capable of pumping the two
components in
their proper proportions into the delivery system described in this Patent
document.
[0023] The foam delivery system 10 may be used in a variety of applications,
for example
for stabilizing and/or densifying base soils at extreme depths, for
stabilizing around the base
of screw-piles and other types of piles that have been screwed or placed at
depth, for
densifying base soils in earth quake prone zones as a prevention against
liquefaction, for
filling voids along vertical planes at depth in such cases as for example old
mine tunnels and
shafts, new mining tunnels and shafts, conduits, or any other structure
resting along a vertical
plane that requires back-filling and stabilization and for filling voids along
horizontal planes
in such cases as for example abandoned conduit, culverts, mined tunnels, or
any other
structure resting along a horizontal plane that requires void-filling.
[0024] Immaterial modifications may be made to the embodiments described here
without
departing from what is covered by the claims.
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