Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02349538 2001-04-27
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Screen Assemblies for a Vibratory Separator
The present invention relates to screen assemblies
for a vibratory separator and, more particularly but not
exclusively, to screen assemblies for use in shale
shakers. The present invention also relates to a
releasable locking device for securing a screen assembly
to a vibratory separator.
When drilling a wellbore in the earth's surface,
drilling fluid is used to maintain the tip of a drill
cool and to carry solids to the surface of the wellbore
.
'. Once at the surface the solids are removed from the
drilling fluid which can then be re-used.
Types of apparatus that can remove solids from
drilling fluid include a vibratory separator known as
I5 shale shaker. Typically, it is known to provide such
equipment with one or more screens of wire mesh for
filtering the drilling fluid. Typically, the wire mesh is
very fine and does not have a high durability.
The problem of providing the necessary durability to
known screens has been addressed, in one manner, by
bonding the wire mesh to a perforated plastic plate. An
example of this is described in W094/15723.
However, although perforated plates increase the
durability of such screens, they have a "blinding" effect
on the screen in which throughput of the drilling fluid
is reduced.
In addition, it is known to mount a screen in a
frame prior to use in order to make for faster fitting
and removal to a shale shaker.
US-A-5 598 930 discloses a screen for a shale shaker
which comprises an undulating wire mesh screen which is
supported by a series of flat or undulating strips which
are mounted in a frame or between two frame sides.
US-A-4 033 865 discloses a vibratory screening
apparatus having a pair of flat screen cloths mounted in
AA~IFNn~n cu~~r
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face-to-face abutment, with the wires of the lower flat
screen cloth intersecting the openings of the upper
screen cloth so as to inhibit blinding. During vibration,
there is slight relative motion between the two wire mesh
screens, with the upper mesh screen moving away from and
back toward the lower screen.
However, since such screens are typically
constructed off-site, use of frames makes the screens
rigid and awkward to transport and handle, and requires
IO larger storage space. The frame itself also contributes
!_ to the blinding effect. In contrast screening material
can often be transported in rolls.
The present invention seeks to address at least one
or more disadvantages of the prior art.
According to one aspect of the present invention
there is provided a screen assembly for a vibratory
separator, the screen assembly comprising
at least one wire mesh screen formed with undulating
mesh material having a series of ridges spaced apart by a
series of valleys, characterised by a first series of
spaced apart corrugated rods, the arrangement being such
that, in use, the wire mesh screen is supported by the
first series of spaced apart corrugated rods.
Such an arrangement addresses the problem of
providing the necessary support to the screen whilst at
the same time inhibiting the effects of "blinding".
Advantageously, said first series of spaced apart
rods extend in a direction which is transverse to the
ridges and valleys of said at least one wire mesh screen.
Preferably, said screen assembly further comprises a
second series of spaced apart rods arranged, in use, to
support said first series of spaced apart rods.
Advantageously, said second series of spaced apart
rods extend transverse to said first series of spaced
apart rods.
_ e~n~mn~n cu~cn-
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Preferably, said first series of spaced apart rods
are corrugated.
Advantageously, said first series of spaced apart
rods have a corrugated surface
Preferably, the at least one wire mesh screen
comprises a plurality of two or more wire mesh screens.
Advantageously, the plurality of wire mesh screens
are adhered together.
Preferably, the at least one wire mesh screen
includes at least one upper wire mesh screen having a
f_ first mesh size and a lower wire mesh screen having a
mesh size coarser than the first screen mesh size.
Advantageously, said screen comprises a pair of
spaced apart top bars, one top bar on each side of the
screen assembly at an outer edge thereof.
Preferably, the undulating shape of the at least one
wire mesh screen forms a series of end openings on two
sides thereof, and said screen assembly further comprises
plug apparatus for, in use, plugging said series of
end openings.
Advantageously said series of end openings are
encapsulated in encapsulating material.
Preferably, said screen assembly further comprises a
perforated corrugated plate which supports said at least
one wire mesh screen.
Advantageously, the at least one wire mesh screen is
adhered to the corrugated perforated plate,
Preferably, said screen assembly further comprises
an adapter bar on which the at least one wire mesh
screen is mounted,
the adapter bar having recesses for receiving the
first series of spaced-apart rods.
Advantageously, said screen assembly further
comprises
a layer of seal material on top of the adapter bar.
A1~1ENDED SHEET
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According to another aspect of the present invention
there is provided a screen assembly for a vibratory
separator, the screen assembly comprising
at least one wire mesh screen formed with undulating
mesh material having a series of ridges spaced apart by a
series of valleys, and
a layer of wire mesh material, the arrangement being
1 such that, in use, the at least one wire mesh screen is
supported by the layer of wire mesh material.
Such an arrangement addresses the problem of
providing the necessary support to the screen whilst at
the same time inhibiting the effects of "blinding".
Preferably, said layer of wire mesh material has a
coarser mesh than said at least one wire mesh screen.
Advantageously, said screen assembly further
comprises a perforated corrugated plate which supports
said at least one wire mesh screen.
Preferably, the at least one wire mesh screen is
adhered to the corrugated perforated plate.
Advantageously, the at least one wire mesh screen
v
comprises a plurality of two or more wire mesh screens.
Preferably, the plurality of wire mesh screens are
adhered together.
Advantageously, the at least one wire mesh screen
includes at least one upper wire mesh screen having a
first mesh size and a lower wire mesh screen having a
mesh size coarser than the first screen mesh size.
Preferably, said screen assembly further comprises a
pair of spaced apart top bars, one top bar on each side
of the screen assembly at an outer edge thereof.
Advantageously, the undulating shape of the at least
one wire mesh screen forms a series of end openings on
___ _..__~ ,~", ~ .,~. AMENDED~o EET
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two sides thereof, and further comprising
plug apparatus for, in use, plugging said series of
end openings.
Preferably, said series of end openings are
encapsulated in encapsulating material.
Advantageously, the at least ane wire mesh screen
has opposed spaced-apart front and rear edges
encapsulated in encapsulating material.
Preferably there is provided a vibratory separator
fitted with a screen in accordance with the present
invention, wherein said screen assembly is not mounted in
a frame .
According to another aspect
of the present invention
there is provided a frameless screen assembly for a
vibratory separator, the frameless screen assembly
comprising
at least one wire mesh screen formed with undulating
mesh material having a series of ridges spaced apart by
a
series of valleys, and
a first series of spaced apart rods, the arrangement
being such that, in use, the wire mesh screen is
C
supported by the first series of spaced apart rods.
According to another aspect
of the present invention
there is provided a frameless screen assembly for a
vibratory separator, the frameless screen assembly
comprising
at least one wire mesh screen formed with undulating
mesh material having a series of ridges spaced apart by
a
series of valleys, and
a layer of wire mesh material,
the arrangement being
such that, in use, the at least one wire mesh screen is
supported by the layer of wire mesh material.
-- AMENDED SHEET
02349538 2001-04-27
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A screen assembly in accordance with the present
invention, in preferred embodiments, does not require a
wire mesh screen to be mounted in or on a frame before
being fitted to a shale shaker. Farther, said screen
assemblies do not require the support of planar
perforated plates and can be mounted directly on the wear
strip of certain shale shakers. In alternative preferred
embodiments the wire mesh screen can be mounted directly
on a certain shale shakers with standard clamp/hookstrip
arrangements.
According to another aspect of the present invention
there is provided a releasable locking device for
securing a screen assembly to a vibratory separator,
which releasable locking device comprises
an arm movable between a first position and a second
position,
a plunger pivotally connected to said arm for, in
use, retaining said screen assembly to said vibratory
separator in said first position and releasing said
screen assembly from said vibratory separator in said
second position, and
first spring means for, in use, inhibiting movement
of said arm from said first and second positions.
Advantageously, said releasable locking device
further comprises second spring means for, in use,
inhibiting movement of said arm from said first position.
AMENDED SHEET
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For a better understanding of the present invention
reference will now be made, by way of example, to the
accompanying drawings in which:-
Fig. lA is a top plan view, partially cut away, of a
first embodiment of a screen according to the present
invention;
Fig. 1B is an exploded view of one end of the screen
of Fig. lA;
Fig. 1C is a view of one end of the screen of Fig.
lA;
Fig. 1D is an exploded view of one side of the
screen of Fig. lA;
Fig. 2A is a top plan view, partially cut away, of a
second embodiment of a screen according to the present
invention;
Fig. 2B is an exploded view of one end of the screen
of Fig. 2A;
Fig . 2C is a view of one end of the screen of Fig .
2A.
Fig. 2D is an exploded view of one side of the
screen of Fig. 2A;
Fig. 3A is a top plan view, partially cut away, of a
third embodiment of a screen according to the present
invention;
Fig. 3B is an exploded view of one end of the screen
of Fig. 3A;
Fig. 3C is a view of one end of the screen of Fig.
3A;
Fig. 3D is an exploded view of one side of the
screen of Fig. 3A;
Fig. 3E is an exploded view of one side of the
screen of Fig. 3A and mounting
an adapter the
bar for
screen on a vibratory separatorapparatus;
Fig . 3F is a view of one end
of part of a screen
in
accordance present invention on a mounting
with the
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structure of a vibratory shaker apparatus;
Fig. 3G is a view of one end of an adapter bar of
the apparatus of Fig. 3E;
Fig. 9A is a top plan view, partially cut away, of a
fourth embodiment of a screen in accordance with the
present invention;
Fig. 4B is an exploded view of one end of the screen
of Fig. 4A;
Fig. 4C is a view of one end of the screen of Fig.
4A;
Fig. 5A is a top plan view, partially cut away, of a
fifth embodiment of a screen in accordance with the
present invention;
Fig. 5B is an exploded view of one end of the screen
of Fig. 5A;
Fig. 5C is a view of one end of the screen of Fig.
5A;
Fig. 5D is an exploded view of one side of the
screen of Fig. 5A;
Fig. 6 is a view of one side of a screen locking
apparatus in use with a screen in accordance with the
present invention;
Fig . 7A a.s a side view of a first embodiment of
a
releasable screen locking apparatus in accordance with
the present invention;
Fig. 7B shows the apparatus of Fig. 7A in an
unlocked position;
Fig. 7C is a top plan view of the apparatus of Fig.
7B; and
Fig. 8 is a side view of a second embodiment of
a
releasable screen locking apparatus in accordance with
the present invention.
Referring to Figs. lA - 1D there is shown a screen
130 which comprises wire mesh layers 131, 132, 133 (any
or any two of which are optional) mounted over rods 136.
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Optionally, the wire mesh layers 131, 132, 133 may be
adhered (adhesively, by sintering, and/or bonding)
together. The rods 136 may be made of metal (e. g. steel,
stainless steel, zinc, zinc alloys, aluminium, aluminium
alloys, copper, copper alloys) plastic, composite or
fiberglass. The rods 136 are substantially circular in
cross-section, although it is envisaged that any suitable
shape cross-section may be employed. Top bars 135 extend
along two sides of the screen 130. Open ends of the
screen 130 on two sides thereof are plugged with plugs
137 which are made of any suitable metal, plastic (e. g.
urethane), wood, fiberglass, or composite material and
are held in place by a friction fit and/or suitable
adhesive including but not limited to epoxy or glue (e. g.
but not limited to commercially available 3M Jet Melt or
3M TS230). Also, preferably, front and rear edges 142,
143 of the screen 130 are encapsulated by the adhesive or
glue (e . g . but not limited to urethane) . An adapter bar
140 has recesses 141 for receiving the rods 136 and a
plurality of bolt holes 148 for attaching the adapter bar
140 to a typical part or wear or seal strip of known
shakers. Optionally, the rods 136 may be adhered to the
recesses 141. Alternatively, bolts (not shown) may extend
through a shaker basket and into the side of the adapter
bar 140. Seal material (e.g. rubber, plastic BUNA-N,
etc.) 144 may be used on top of the adapter bar 140.
In one aspect the wire mesh layers 131 and 132 are
either l, 2, or 3 mesh and the layer 133 is of a coarser
mesh, a . g . 12 X 12 down to 8 X 8 (or between 8 X 12 and
12 X 8). It is also within the scope of this invention
for the layers 131, 132, 133 to be any mesh size. In one
aspect a screen 130 is made by bonding the layers 131 and
132 into a sheet With epoxy across substantially the
entire surfaces of the layers; then the resulting sheet
is corrugated and the layer 133 is bonded to the sheet.
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In use, the adapter bar 140 is bolted or otherwise
fixed to a shaker. The wire mesh layers 131, 132, 133 and
the rods 136 are then clamped between the top bar 135 and
the adapter bar 140.
The rods 136 inhibit flexing of the screen during
use and increase the longevity of the screen, whilst at
the same time reducing the effects of "blinding". This
arrangement also obviates the need for a frame and/or
planar perforated plate to support the screen. It also
obviates the need for fused plastic to bond the wire mesh
layers together. It is also within the scope of this
embodiment for there to be a second series of rods which
extend transverse to the rods 136 to provide extra
support therefor.
Referring to Figs. 2A - 2D there is shown a screen
260 which comprises wire mesh layers 261, 262, 263 (any
or any two of which may be omitted), corrugated rods 266,
rods 265 underlying parts of the corrugated rods 266, and
encapsulation material 269 (similar to that of the screen
130) which encapsulates front and rear edges of the wire
mesh layers 261, 262, 263 and corrugated rods 266.
Alternatively, some of the internal bars may be included
in the encapsulation material. Top bars 267 are like the
top bars 135 of the screen 130. An adapter bar 268 is
like the bar 140 with side bolt holes 264 for bolting the
adapter bar 268 and the screen 260 attached thereto to a
shaker basket. The adapter bar 268 has rod recesses 264'
and a top seal layer 268' (like the material 144 of
screen 130) .
The screen 260 can be assembled on a shaker i.n a
similar manner to the screen 130. The screen 230 includes
the same benefits as the screen 130. Further, the
corrugated rods 266 increase the contact area with the
screen 260. Therefore the weight of the screen 260 is not
concentrated at the valleys thereof, which helps to
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reduce any local wearing effect that the rods may have on
the screen 260. Further, this is achieved without
"blincling" the screen anymore than the rods 136 blind the
screen 130.
The rods 265 provide extra rigidity to the
corrugated rods 266, although they are not essential for
this embodiment of the invention. The rods 265 could be
spot welded to the corrugated rods 266.
Referring to Figs. 3A - 3E there is shown a screen
330 which comprises wire mesh layers 331, 332, 333 (any
or any two of which are optional) on a perforated
corrugated plate 334 which is mounted over rods 336.
Optionally, the wire mesh layers 331, 332, 333 may be
adhered (adhesively, by sintering, and/or bonding) to the
perforated corrugated plate 334. The rods 336 may be made
of metal (e. g. steel, stainless steel, zinc, zinc alloys,
aluminium, aluminium alloys, copper, copper alloys)
plastic, composite or fiberglass. The rods 336 are
substantially circular in cross-section, although it is
envisaged that any suitable shape cross-section may be
employed. Top bars 335 extend along two sides of the
screen 330. Open ends of the screen 330 on two sides
thereof are plugged with plugs 337 which are made of any
suitable metal, plastic (e. g. urethane), wood,
fiberglass, or composite material and axe held in place
by a friction fit and/or suitable adhesive including but
not limited to epoxy or glue (e.g. but not limited to
commercially available 3M Jet Melt(TM) or 3M TS230).
Also, preferably, front and rear edges 342, 343 of the
screen 330 and the perforated corrugated plate 334 are
encapsulated by the adhesive or glue (e.g. but not
limited to urethane). An adapter bar 340 has recesses 341
for receiving the rods 336 and a plurality of bolt holes
348 for attaching the adapter bar 340 to a typical part
or wear or seal strip of known shakers. Optionally, the
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rods 336 may be adhered to the recesses 341.
Alternatively, bolts (not shown) may extend through a
shaker basket and into the side of the adapter bar 340.
Seal material (e.g. rubber, plastic BUNA-N, etc.) 344 may
be used on top of the adapter bar 340.
In one aspect the wire mesh layers 331 and 332 are
either l, 2, or 3 mesh and the layer 333 is of a coarser
mesh, a . g . 12 X 12 dawn to 8 X 8 (or between 8 X 12 and
12 X 8). It is also within the scope of this invention
for the layers 331, 332, 333 to be any mesh size. The
perforated corrugated plate 334 is, in certain aspects,
made of metal, e.g. but not limited to 20 gauge carbon
steel. In one aspect the screen 330 is made by bonding
the layers 331 and 332 into a sheet with epoxy across
substantially the entire surfaces of the layers; then the
resulting sheet is corrugated and the layer 333 is bonded
to the sheet.
The screen 330 can be assembled on a shaker in a
similar manner to the screens 130 and 230. The perforated
corrugated plate 334 provides extra support to the
screen.
Referring to Fig. 3F the screen 330 is shown clamped
to a shaker basket 346 between a tap bar 335 and a ledge
347 of a shaker basket 346. Clamping is facilitated by
means of a locking bar 338 (hereinafter described).
Referring to Figs. 4A - 4C there is shown a screen
450 which comprises wire mesh layers 451, 452, 453 (any
or any two of which may be omitted) and a wire mesh lower
layer 459 which may be any desired mesh size but which
is, in certain embodiments a coarser mesh than any of the
meshes 451, 452 , 553 . Fig . 4A omits the wire mesh layers
451, 452 , 453 for clarity . In one particular aspect the
wire mesh layer 459 is between 1 X 1 and 4 X 4 mesh
(including between 1 X 4 and 4 X 1 mesh). In particular
embodiments the lower layer of wire mesh 459 is 12 X 12,
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8 X 8 or 4 X 4 mesh, and may include meshes between 8 X
12 to 12 X 8. The layers may have upturned ends 458 so
that the screen 450 may be used with any standard
clamp/hookstrip arrangement. The wire mesh layers 451,
452, 453 may be bonded together as a unit. The upturned
ends 458 may be formed before or after bonding.
Preferably the front and rear edges of the screen 450 are
encapsulated by adhesive or glue and plugs 457 plug
screen ends. The wire mesh lower layer 459 inhibits
flexing of the screen 450 during use and increases
longevity of the screen 550, whilst at the same time
reducing the effects of "blinding". This arrangement also
obviates the need for a frame and/or planar perforated
plate to support the screen. It also inhibits the need
for fused plastic to bond the wire mesh layers together..
As with any screen herein, multiple wire meshes may
be bonded and/or secured together prior to corrugating.
Referring to Figs. 5A - 5D there is shown a screen
550 which comprises wire mesh layers 551, 552, 553 (any
or any two of which may be deleted), a perforated
corrugated plate 554, and a lower layer of wire mesh 559
which may be any desired mesh size but which is, in
certain embodiments a coarser mesh than any of the mashes
551, 552, 553. In one particular aspect the lower layer
of wire mesh 559 is between 1 X 1 and 4 X 4 mesh
(including between 1 X 4 and 4 X 1 mesh). In particular
embodiments the lower layer of wire mesh 559 is 12 X 12,
8 X 8 or 4 X 4 mesh, and may include meshes between 8 X
12 to 12 X 8. The wire mesh layers 551, 552, 553 may have
upturned ends 558 so that the screen 550 may be used with
any standard clamp/hookstrip arrangement. These wire mesh
layers 551, 552, 553 may be bonded together as a unit.
The upturned ends 558 may be formed before or after
bonding. Preferably the front and rear edges of the
screen 550 are encapsulated by adhesive or glue as in the
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screen 430 and plugs 557 plug screen ends as do the plugs
437. The wire mesh lower layer 559 inhibits flexing of
the screen 550 during use and increases longevity of the
screen 550. The perforated carrugated plate 554
reinforces the screen 550 further.
It is within the scope of the invention for a
perforated corrugated plate to be used with any of the
screens disclosed herein.
Referring to Fig. 6 there are shown free latch
levers 639 one in a "down" locking position (the one to
the left in Fig. 6A) locking a screen 130, 230, 330 to
the shaker basket and one in an "up" position from which
a.t is releasable to release the screen from the basket.
In use, the free latch levers 639 clamp the screen 130,
230, 330 between a top bar 135, 235, 335 and one of an
adapter bar 140, 240, 340 and a wear or seal strip (not
shown) of known shakers.
Referring to Fig. 7A - 7D there is shown a
releasable screen locking mechanism 770 far releasably
holding a screen to a basket of a vibratory separator,
for example, a screen 130 with its adapter bars and top
bars is positioned on respective basket ledges (not
shown). As shown in Fig. 7A the releasable screen locking
mechanism 770 releasably holds the screen 130 in place by
clamping the screen 130 between the top bar and the
adapter bar. As shown in Fig. 7B, the releasable screen
locking mechanism 70 is in an "unlock" or release
position permitting the screen 130 (not shown) to be
removed from or inserted into the shaker basket.
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The releasable screen locking mechanism comprises a
body 771 which has a bracket 772 bolted to a shaker
basket wall with bolts (not shown) through holes 773 or
appropriately secured to another part of a shaker. The
body 771 has a hole 774 through which movably extends a
rod 775. Leaf spring 776 are secured to the body 771. The
rod 775 is pivotably mounted to a bar 777 with a pin 778.
A distal end of the bar 777 is pivotably mounted around a
pin or pivot member 779 mounted to the leaf springs 776.
Bolts 781 secured to the pivot member 779 movably extend
through holes 782 in leaf springs 776 and nuts 783
prevent the bolts 781 from escaping from the holes 782 in
the leaf springs. The pivot member 779 fits through the
bar 777. In both over and under centre positions, the bar
777 is releasably biased in place. A first "locked"
position of the releasable screen locking mechanism 770
is shown in Fig. 7A. In the first "locked" position, a
lower end of the rod 775 bears against a top bar of the
screen 130 to releasably hold the screen 130 in a shaker
basket. A second "locked" position is shown in Fig. 7B in
which the screen 130 can be removed from or inserted into
the shaker basket.
Referring to Fig. 8 there is shown another
releasable screen locking mechanism 886 for releasably
holding a screen to a shaker basket. For example, a
screen with its adapter bars and top bars is positioned
on a basket ledge (not shown). The releasable screen
locking mechanism 886 is shown with a bar 887 and plunger
888 in an unlocked position, a locked position indicated
by the bar 878 and plunger 888 in dotted line. A body 889
includes a shaker basket mounting bracket 891 with bolt
holes 872 and holes 893 through which movably extends a
rod 894 of the plunger 888. The rod 894 is pivotably
secured to the bar 878 with a pin 896 and a distal end of
the bar 878 is pivotably mounted about a pivot member
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897. A spring 895 urges the plunger 888 downwardly and is
biased to help maintain the apparatus in a releasable
"locked" position. A spring stop 899 is on the rod 894.
