Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02942960 2016-09-23
PUMP ENCLOSURES FOR MATURE FINE TAILINGS NORMALIZATION
Cross Reference to Related Application
This application claims priority from US Provisional Patent Application No.
62/270926
filed on December 22, 2015.
Technical Field
[0001] The specification relates generally to pumping systems, and
specifically to a
pump enclosure for pumping systems.
Background of the Disclosure
[0002] Used process fluid from mining or oil and gas operations is
conventionally
placed in tailings ponds. The process fluid is generally water carrying
various suspended
solids, including sand and clay particles. In a tailings pond, the suspended
solids can
settle into a layer of material referred to as mature fine tailings (MFT), at
the bottom of
the tailings pond. The MFT material, a portion of which may still be water,
can simply be
left in the tailings pond to thicken and solidify; however, this process may
take an
impractically long period of time. Therefore, attempts have been made to
recover the
MFT from tailings ponds for treatment (such as drying, solidification, heavy
metal
extraction and further bitumen recovery) and final land reclamation.
[0003] Conventional attempts to recover MFT from tailings ponds involve
placing
pumps into the MFT layer in a tailings pond and pumping the MFT out of the
tailings
pond. Such attempts are complicated by the varying consistency of the MFT
material
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)
and, particularly, the presence of debris such as tree branches, other
vegetation and
industrial debris in the MFT. The presence of such debris in the MFT layer can
lead to
frequent periods of downtime for maintenance, requiring pump removal from the
tailings
pond to clear debris from the pump inlets, or repair of clogged and/or damaged
pumps
following the ingestion of debris.
Summary
[0004] In a first aspect, there is provided a pump enclosure. The pump
enclosure
includes at least one wall defining a chamber for enclosing a pump, and at
least one
opening in the wall permitting passage of a material to be pumped. At least a
portion of
the wall is at a distance greater than a threshold from an inlet of the pump.
[0005] By reducing or preventing the entry of debris to within at
least a threshold
distance of the pump inlet, the pump enclosure may not only reduce the
likelihood of
pump blockage/damage, but may also restrain debris at a sufficient distance
from the
pump inlet that the likelihood of the debris impinging against the outside of
the enclosure
and clogging one or more openings in the enclosure is reduced. Such enclosures
may
therefore facilitate the process of pumping thick debris entrained tailings
(e.g. MFT) such
as those generated as a by-product of the oil sands extraction process.
[0006] In certain embodiments, the threshold is an inlet diameter of
the pump.
[0007] In certain embodiments, the threshold is a multiple of the inlet
diameter.
[0008] In certain embodiments, the at least one wall includes a side
wall having first
and second ends, and a lower wall connected to the second end of the side
wall.
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[0009] In certain embodiments, the side wall is substantially
cylindrical.
[0010] In certain embodiments, the at least one opening includes a
plurality of
openings defined through side wall.
[0011] In certain embodiments, the side wall includes a plurality of
rods connected to
the lower wall, and the plurality of openings are defined between adjacent
ones of the
rods.
[0012] In certain embodiments, the at least one wall includes an upper
wall connected
to the first end of the side wall.
[0013] In certain embodiments, the upper wall includes an opening
therein for
receiving the pump.
[0014] In certain embodiments, the pump enclosure further includes at
least one
macerator.
[0015] In certain embodiments, the at least one macerator is mounted in
an opening
in the side wall. The macerator has an inlet for receiving material from the
exterior of the
chamber, and an outlet for discharging the material into the chamber.
[0016] In certain embodiments, the at least one macerator is mounted
adjacent to the
side wall. The macerator has an inlet for receiving material from the exterior
of the
chamber, and an outlet for discharging the material to the exterior of the
chamber.
[0017] In certain embodiments, the at least one macerator is mounted
moveably
adjacent to the side wall.
[0018] In certain embodiments, the side wall and the lower wall are
impermeable.
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,
[0019] In certain embodiments, the opening in the upper wall is
configured to receive
a plurality of pumps.
[0020] In certain embodiments, the opening in the upper wall is
configured to
surround a barge supporting the plurality of pumps.
[0021] In certain embodiments, the upper wall is buoyant.
[0022] Other aspects, features, and advantages will become apparent
from the
following detailed description when taken in conjunction with the accompanying
drawings, which are a part of this disclosure and which illustrate, by way of
example,
principles of the inventions disclosed.
Description of the Figures
[0023] The accompanying drawings facilitate an understanding of the
various
embodiments.
[0024] FIG. 1 depicts a pump system including a pump enclosure,
according to a
non-limiting embodiment;
[0025] FIGS. 2A and 2B depict an embodiment of the pump enclosure of
FIG. 1,
according to a non-limiting embodiment;
[0026] FIG. 3 depicts another pump enclosure, according to a non-
limiting
embodiment;
[0027] FIG. 4 depicts a further pump enclosure, according to a non-limiting
embodiment;
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[0028] FIG. 5 depicts a still further pump enclosure, according to a non-
limiting
embodiment; and
[0029] FIGS. 6A and 6B depict yet another pump enclosure, according to a
non-
limiting embodiment.
Detailed Description
[0030] Figure 1 depicts a pump system 100 for use in a body of fluid
104. The body
of fluid 104 can contain any one of, or any combination of, used or unused
process water,
treated wastewater effluent, mature fine tailings (MFT), slurry and the like,
resulting
from mining operations and related activities. In the present example
embodiment, the
body of fluid 104 contains a bed of MFT 108 adjacent to a bottom 112 of the
body of
fluid 104. In addition, the MFT 108 or any other portion of the body of fluid
104 can
contain debris 116, such as vegetation (e.g. tree branches). The pump system
100 is
operated to reclaim the MFT 108 from the body of fluid 104 and deliver the
reclaimed
MFT to other equipment (not shown) for processing, such as drying and
disposal.
[0031] The pump system 100 includes a pump support 120, such as a barge
configured to float at a surface 124 of the body of fluid 104. The pump
support 120
supports a pump 128, such as a submersible vertical turbine pump (VTP), from a
line
132. The line 132 can include a fluid discharge hose from the pump 128, as
well as one or
more conduits for supplying power to the pump 128 and exchanging control data
with the
pump 128. In other embodiments, the fluid discharge hose can be separated from
the line
132.
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[0032] In addition, the system 100 includes a pump enclosure 136. The
pump
enclosure 136 includes one or more walls defining a chamber 138 for enclosing
the pump
128. At least one of the walls defining the chamber 138 includes at least one
opening
therein for permitting the entry of material (such as MFT) into the chamber
138, to be
collected by the pump 128 and delivered to the pump support 120 or other
equipment for
processing. The opening can also be configured to reduce or eliminate the
entry of debris
116 or other material into the pump enclosure 136 that may damage the pump 128
or
interrupt the operation of the pump 128. Further, when the pump enclosure 136
is
installed around the pump 128, the distance between at least a portion of the
walls of the
pump enclosure 136 and an inlet of the pump 128 is greater than a predefined
threshold.
The pump, when in operation, 128 exerts suction pressure on material
surrounding the
inlet. The suction pressure exerted by the pump 128 causes the material to
move towards
the inlet at an increasing radial velocity. This fluid velocity is
proportional to the distance
from the pump suction and decreases radially from the pump inlet. The
filtering action of
the walls of the pump enclosure 136, in the relatively low velocity field,
located at some
radial distance from the pump suction, effectively increases the filtration
efficiency of the
present invention over that of a simple pump strainer for two reasons: the
lower transit
velocity of the media through the screen of the pump enclosure reduces the
pressure drop
across the screen and the larger surface area of the pump enclosure screen, as
compared
to the pump suction strainer, provides a larger surface area than the pump
strainer thereby
reducing the possibility of total flow blockage.
[0033] The threshold distance is selected such that beyond the threshold
distance, the
velocity of material that is pulled towards the inlet of the pump 128 is
reduced
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sufficiently to reduce or eliminate the likelihood of material (e.g. debris
116) clogging the
above-mentioned opening in the walls of the pump enclosure 136. Various
embodiments
of the pump enclosure 136 will be described in greater detail below.
[0034] Referring now to Figure 2A, the pump support 120 is illustrated
with two
pumps 128 suspended therefrom into the body of fluid 104 by respective lines
132. In
other embodiments, more than two pumps 128 can be suspended from the pump
support
120. In further embodiments a single pump 128 can be suspended from the pump
support
120.
[0035] One of the pumps 128 suspended from the pump support 120 is
enclosed in a
pump enclosure 136. In other embodiments, both pumps 128 suspended from the
pump
support 120 can be enclosed in respective pump enclosures. More generally, in
some
embodiments every pump 128 suspended from the pump support 120 can be enclosed
in
a pump enclosure 136.
[0036] The chamber 138 of the pump enclosure 136 is defined by a side
wall 200, a
lower wall 204 and an upper wall 208. The side wall 200 is a substantially
cylindrical
side wall in the present example. In other embodiments, the side wall 200 can
have the
shape of a rectangular prism. The side wall 200 is connected at a lower end to
the lower
wall 204, and at an opposite, upper end to the upper wall 208.
[0037] As mentioned earlier, the pump enclosure 136 includes at least
one opening to
allow entry of material from the body of fluid 104 into the pump enclosure 136
for
collection by the pump 128. In the present example, the side wall 200 includes
a plurality
of spaced apart rods 212 (see Figure 2B) extending between the upper wall 208
and the
lower wall 204. The at least one opening thus includes a plurality of
openings, each
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opening being defined by the space between two adjacent rods 212. In other
embodiments, the side wall 200 can include a mesh instead of the set of rods
212 shown
in Figures 2A and 2B.
[0038] The pump enclosure 136 can include further openings in addition
to those
defined in the side wall 200. For example, the lower wall 204 of the pump
enclosure 136
can also include additional openings. In the example illustrated in Figures 2A
and 2B, the
lower wall 204 includes a ring 216 and a plurality of rods 220 extending along
chords of
the ring 216 (that is, from one point on an inner side of the ring 216 to
another point on
the inner side). The spaces between adjacent ones of the rods 220 are openings
in the
lower wall 204.
[0039] In some embodiments, the upper wall 208 can also include an
opening therein.
For example, as seen in Figure 2A, the upper wall 208 includes an opening 224
therethrough to allow passage of the line 132. In some embodiments, the
opening 224 can
also be large enough to allow passage of the pump 128 therethrough. In such
embodiments, the enclosure 136 can be installed in the body of fluid 104, for
example by
anchoring the enclosure (e.g. via the lower wall 204 and/or upper wall 208) to
the bottom
112 of the body of fluid 104. One or both of the lower wall 204 and the upper
wall 208
can be buoyant, to maintain the orientation of the enclosure 136 relative to
the bottom
112. Once the enclosure 136 is installed, the pump 128 can be lowered from the
pump
support 120 into the enclosure 136 via the opening 224. The position of the
pump 128
can also be adjusted within the chamber 138 during operation by spooling or
unspooling
the line 132 from the pump support 120.
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[0040] The pump enclosure 136 can also include further openings defined
in the side
wall 200. In particular, as seen in Figures 2A and 2B, a plurality of openings
in the side
wall 200 can each accommodate a macerator 228. In the present embodiment, the
pump
enclosure 136 includes four macerators 228. In other embodiments, more than
four
macerators 228 can be included. In further embodiments, as few as zero
macerators 228
can be included in the pump enclosure 136 (that is, the macerators 228 can be
omitted
entirely). Further, the position of the macerators 228 can be varied. In the
present
example, the macerators 228 protrude through the side wall 200 adjacent to the
lower
wall 204. In other embodiments, the macerators 228 can be placed in the side
wall 200 at
any suitable location intermediate to the lower wall 204 and the upper wall
208. In further
embodiments, each macerator 228 can be placed at a different height in the
side wall 200
from the other macerators 228.
[0041] Each of the macerators 228 includes an inlet for receiving
material from the
body of fluid 104, one or more grinding or cutting mechanisms for reducing
breaking the
material received at the inlet into pieces, and an outlet for discharging the
pieces into the
chamber 138. Power supply and control signals for the macerators 228 can
travel along
the line 132 or be supplied from a separate floating companion barge.
[0042] As also mentioned earlier, the distance between at least a
portion of the walls
200, 204 and 208 and an inlet 232 of the pump 128 is greater than a
predetermined
threshold. In the present example, the predetermined threshold distance is a
fraction or
multiple of the diameter "D" of an inlet 232 of the pump 128. In some
embodiments, the
threshold is equivalent to at least one inlet diameter. Thus, for a pump inlet
diameter of
about eight inches, the threshold distance is about eight inches from the pump
inlet. In
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further embodiments, the threshold is equivalent to at least two inlet
diameters. Thus, for
a pump inlet diameter of about eight inches, the threshold distance is about
sixteen inches
from the pump inlet. In other embodiments, the threshold is equivalent to a
greater
multiple of the inlet diameter than two. In further embodiments, the threshold
is
equivalent to a multiple of the inlet diameter that is between one and two.
[0043] Thus, at least a portion of at least one of the side wall 200,
the lower wall 204
and the upper wall 208 is further from the inlet 232 than the threshold
distance as defined
above. In the present embodiment, the entirety of each of the walls 200, 204
and 208 are
further from the inlet 232 than the threshold distance as defined above.
Maintaining at
least the threshold distance between the inlet 232 and at least a portion of
the walls of the
enclosure 136 reduces the velocity of material (imparted by the pump 128) at
the
openings in the walls of the enclosure 136, and therefore can reduce the
likelihood of the
openings becoming clogged with debris. In addition, the outlets of each the
macerators
228 are preferably further from the inlet 232 than the threshold distance as
defined above.
This allows the macerated flow stream to blend and normalize prior to passage
through
the pump suction strainer reducing the possibility of pump suction blockage.
[0044] Referring now to Figure 3, a pump enclosure 336 according to a
further
embodiment is illustrated. The pump enclosure 336 defines a chamber 338 within
a side
wall 300 connected between a lower wall 304 and an upper wall 308. The side
wall 300 is
substantially cylindrical in the present embodiment. In other embodiments, the
side wall
300 can have other configurations, including the shape of a rectangular prism.
The side
wall 300 includes a plurality of spaced apart rods 312, and thus defines
openings between
adjacent rods 312. The lower wall 304 includes a ring 316 and a plurality of
rods 320
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extending along chords of the inner side of the ring 316, thus forming
additional openings
between the chamber 338 and the exterior of the chamber 338.
[0045] In addition, the upper wall 308 defines an opening 324 therein.
While the
pump enclosure 136 illustrated in Figures 2A and 2B enclosed a single pump
128, the
pump enclosure 336 encloses a plurality of pumps 128. In particular, the
opening 324 in
the upper wall 308 is sufficiently large to surround the entirety of the pump
support 120.
The chamber 338 defined by the upper wall 308, the side wall 300 and the lower
wall 304
is sufficiently large to enclose the plurality of pumps 128 suspended from the
pump
support 120.
[0046] In the installed position, the pump enclosure 336 can be anchored to
the
bottom 112 of the body of fluid 104, for example by anchor lines connected to
the lower
wall 304 and/or the upper wall 308. The upper wall 308, the lower wall 304, or
both, can
be buoyant to assist in maintaining the orientation of the pump enclosure 336.
The upper
wall 308 can lie below the surface 124 in the installed position in some
embodiments. In
other embodiments, a portion of the upper wall 308 can rise above the surface
124 of the
body of fluid 104. In such embodiments, the portion of the upper wall 308 that
rises
above the surface 124 may provide protection for the pump support 120 from
waves and
debris floating on the surface 124.
[0047] As seen in Figure 3, the distance from the inlet of each pump 128
enclosed
within the pump enclosure 336 exceeds the above-mentioned threshold distance
of the
inlet diameter "D" of the pump 128.
[0048] Referring now to Figure 4, a further embodiment is illustrated in
the form of a
pump enclosure 436. Certain components of the pump enclosure 436 are as
described
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above in connection with the pump enclosure 336. Those components bear similar
reference characters to the components of the pump enclosure 336, but with a
leading '4'
rather than a leading '3'. Thus, the chamber 438, the side wall 400, the lower
wall 404,
the upper wall 408, are as described above in connection with the chamber 338,
the side
wall 300, the lower wall 304, the upper wall 308, respectively. The same
principle applies
to the ring 416, the rods 412 and 420, and the opening 424.
[0049] In addition, the pump enclosure 436 includes a plurality of
macerators 428
mounted in the side wall 400. As described in connection with the macerators
228 shown
in Figure 2, the macerators 428 collect material from outside the chamber 438,
grind or
cut the material, and discharge the ground or cut material into the chamber
438. In the
present embodiment, the pump enclosure 436 includes ten macerators 428 (eight
macerators 428 are visible in Figure 4). In other embodiments, fewer than ten
macerators
428 can be provided, including zero macerators, as seen in the embodiment of
Figure 3.
In further embodiments, a number of macerators 428 greater than ten may be
provided.
The positions of the macerators 428 can also be varied within the side wall
400.
[0050] Referring to Figure 5, a further pump enclosure 536 is
illustrated. The pump
enclosure 536 includes a chamber 538 defined by a side wall 500, a lower wall
504 and
an upper wall 508. As in the embodiments of Figures 3 and 4, the pump
enclosure 536
surrounds the pump support 120 and thus the chamber 538 encloses all the pumps
128
suspended from the pump support 120. However, the walls 500, 504 and 508 of
the pump
enclosure 536 are solid and impermeable, rather than made of rods or mesh as
in the
embodiments described above. The upper wall 508 preferably extends above the
surface
124 of the body of fluid 104.
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[0051] The pump enclosure 536 includes at least one opening in the side
wall 500, in
the form of a plurality of macerators in the side wall 500. In the present
embodiment, in
which the upper wall 508 extends above the surface 124 of the body of fluid
104, the
macerators 528 provide the only openings from within the body of fluid 104
into the
chamber 538.
[0052] In the embodiments of Figures 3, 4 and 5, the installation of the
pump
enclosures 336, 436 and 536 can be performed by, for example, floating the
pump
enclosure to the planned location of operation of the pump support 120 in the
body of
fluid, and then sinking the pump enclosures into the body of fluid to the
desired depth
and anchoring the pump enclosures. The pump support 120 can then be floated
over the
pump enclosures. In other embodiments, the pump enclosures and the pump
support can
be floated out to the desired position within the body of fluid 104 together
(with the pump
support 120 already surrounded by the pump enclosure). The pump enclosure can
then be
sunk and anchored. Following placement of the pump enclosure and the pump
support
120, the pumps 128 can be deployed from the pump support 120 into the chamber
338,
438 or 538.
[0053] Referring now to Figures 6A and 6B, a further pump enclosure 636
is
illustrated. The pump enclosure 636 defines a chamber 638 that encloses at
least a portion
of a pump 128. More specifically, at least the portion of the pump 128 that
bears the inlet
232 is enclosed within the chamber 638. The chamber 638 can be defined by a
side wall
600 connected between a lower wall 604 and an upper wall 608. At least one of
the walls
600, 604 and 608 includes at least one opening. For example, the side wall 600
can be
made of a mesh or grating, and can therefore include a plurality of openings
therein for
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material to enter the chamber 638 from the body of fluid 104. The side wall
600 is
illustrated as being substantially cylindrical in shape in Figure 6A. In other
embodiments,
the side wall 600 can have other shapes, including the shape of a rectangular
prism.
[0054] The lower wall 604 and the upper wall 608 can be substantially
disc-shaped
walls, with the exception of a slot cut into each of the walls 604 and 608 to
allow for the
passage of a discharge hose 650 from the pump 128. The side wall 600 can also
protrude
inwardly to form a channel allowing the passage of the discharge hose 650. In
other
embodiments, the discharge hose 650 can rest on the upper wall 608 and travel
along the
outermost extent of the side wall 600 before returning to the pump support
120. In such
embodiments, the walls 600, 604 and 608 can omit the above-mentioned slots and
channels.
[0055] In some embodiments, the upper wall 608 can be sufficiently
buoyant to
support the pump enclosure 636, without the pump 128, at or near the surface
124 of the
body of fluid 104. Thus, to install the pump 128 within the enclosure 636, the
enclosure
636 can be floated adjacent to the pump support 120, and the pump 128 can be
lowered
into the upper wall 608. In some embodiments, the upper wall 608 can include a
coupling
mechanism for securing the pump 128 to the upper wall 608. Upon insertion of
the pump
128, the pump 128 and the enclosure 636 together can be lowered from the pump
support
120 via the line 132 to the desired depth within the body of fluid. The
additional weight
of the pump 128 can be greater than the buoyancy provided by the upper wall
608, thus
allowing the assembled pump enclosure 636 and pump 128 to descend into the
body of
fluid 104.
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[0056] In some embodiments (not shown), the pump enclosure 636 can also
include
one or more macerators mounted in the side wall 600. For example, in some
embodiments four macerators can be mounted in the side wall 600 adjacent to
the lower
wall 604.
[0057] Variations to the above embodiments are contemplated. For example,
the
pump 128 can include a cage or strainer at the inlet 232 in any of the above
embodiments,
to prevent any debris that reaches the interior of the pump enclosures from
entering the
inlet 232 and damaging or interrupting the operation of the pump 128.
[0058] In additional embodiments, the alternative configurations are
contemplated for
the macerators 228 and 428, as well as the macerators mentioned in connection
with the
embodiment illustrated in Figures 6A and 6B. As discussed above, each
macerator has a
flow path (from inlet, to grinding or cutting elements, to outlet) that
travels from the
exterior of the pump enclosures to the interior of the pump enclosures (the
chambers 238,
438, 638). In other embodiments, each macerator can instead have a flow path
that is
substantially parallel to the side wall of the pump enclosure. That is, the
macerator can be
mounted outside the side wall of the pump enclosure, and both ingest debris
and
discharge cut or ground debris outside the side wall. Such macerators can also
be
movably connected to the exterior of the pump enclosures. For example,
referring to
Figure 4, one or more of the macerators 428 can be mounted on a track on the
ring 416
and can travel on the track around the exterior of the side wall 400 to clear
accumulated
debris.
[0059] In further embodiments, the pump enclosures can include
additional pumping
devices adjacent to the inlets of the macerators. For example, an eductor can
be placed
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near the inlet of each macerator to increase the flow of material (e.g. MFT)
into the
macerator.
[0060] Various advantages to the embodiments described herein will now
be
apparent. For example, by reducing or preventing the entry of debris to within
at least a
threshold distance of the pump inlet, the enclosures described above not only
reduce the
likelihood of suction blockage and/or damage to the pump, but also restrain
any debris in
the body of fluid at a sufficient distance from the pump inlet that the
likelihood of the
debris impinging against the outside of the enclosure and clogging one or more
openings
in the enclosure is reduced. In addition, in embodiments that include
macerators, debris
that may otherwise impede the operation of pumps is not only prevented from
impeding
the operation of the pumps, but can also be reduced in size sufficiently to be
removed
from the body of fluid 104 by the pumps.
[0061] In the foregoing description of certain embodiments, specific
terminology has
been resorted to for the sake of clarity. However, the disclosure is not
intended to be
limited to the specific terms so selected, and it is to be understood that
each specific term
includes other technical equivalents which operate in a similar manner to
accomplish a
similar technical purpose. Terms such as "left" and right", "front" and
"rear", "above"
and "below" and the like are used as words of convenience to provide reference
points
and are not to be construed as limiting terms.
[0062] In this specification, the word "comprising" is to be understood in
its "open"
sense, that is, in the sense of "including", and thus not limited to its
"closed" sense, that is
the sense of "consisting only of'. A corresponding meaning is to be attributed
to the
corresponding words "comprise", "comprised" and "comprises" where they appear.
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[0063] In addition, the foregoing describes only some embodiments of the
invention(s), and alterations, modifications, additions and/or changes can be
made thereto
without departing from the scope and spirit of the disclosed embodiments, the
embodiments being illustrative and not restrictive.
[0064] Furthermore, invention(s) have described in connection with what are
presently considered to be the most practical and preferred embodiments, it is
to be
understood that the invention is not to be limited to the disclosed
embodiments, but on
the contrary, is intended to cover various modifications and equivalent
arrangements
included within the spirit and scope of the invention(s). Also, the various
embodiments
described above may be implemented in conjunction with other embodiments,
e.g.,
aspects of one embodiment may be combined with aspects of another embodiment
to
realize yet other embodiments. Further, each independent feature or component
of any
given assembly may constitute an additional embodiment.
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