Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 03159329 2022-04-27
WO 2021/102583
PCT/CA2020/051626
Tesla Turbine Pump and Associated Methods
FIELD OF THE INVENTION
[0001] The present technology relates to a pump based on a Tesla turbine
acting as
a pump.
BACKGROUND
[0002] A Tesla turbine pump consists of a set of smooth discs which are
rotated to
impart motion to a fluid. The fluid enters between the discs near the center,
is given
energy by the rotating discs, then exits at the periphery. A Tesla turbine
does not
generally use friction; instead, it uses the boundary-layer effect on the
discs to impart
motion to the fluid.
[0003] US 4,402,647 discloses a vaneless fluid impeller of the friction type
including
a plurality of co-rotating aligned spaced annular discs mounted for rotation
about a
common axis.
[0004] US 4,773,819 discloses a pump for pumping a slurry includes a rotary
pump
having a plain disc impeller disposed in a cylindrical chamber of a housing
with an
inlet coaxial of the impeller into the housing.
[0005] US 5,191,247 discloses a cooling fan positioned within the casing of an
electric motor comprising a plurality of closely spaced frustoconical discs
carried by
the motor shaft which draw intake air past the motor rotor and stator when
they are
rotated.
[0006] US 6,261,052 discloses an apparatus comprising a longitudinally
extending
housing having a fluid inlet port and a fluid outlet port; and, at least one
plurality of
spaced apart members, each member rotatably mounted in the housing and having
a
pair of opposed surfaces to transmit motive force between fluid introduced
through
the fluid inlet port and the spaced apart members, the surface area of the
opposed
surfaces varying between at least some of the immediately adjacent spaced
apart
members.
[0007] US 2006/0216149 discloses several disc assemblies of a bladeless
compressor, pump or turbine.
[0008] US 6,227,796 discloses an impeller comprising a fluid induction core of
flow
passages spiraling axially about the impeller's rotational axis and a stack of
circular
discs extending radially and concentrically from the induction core.
- 1 -
CA 03159329 2022-04-27
WO 2021/102583
PCT/CA2020/051626
SUMMARY
[0009] In accordance with the invention, there is provided a liquid pump
comprising:
a housing having an inlet disposed at an upstream end and an outlet
disposed at a downstream end opposite the inlet;
a shaft extending through the housing along a center axis of the housing and
configured to be rotated about a rotation axis by a motor; and
one or more pumping stages connected along the shaft in a co-axial
arrangement, each pumping stage comprising a disc impeller comprising multiple
axially spaced discs, each disc having a central opening such that when the
disc
impeller is rotated, liquid entering the disc impeller through the central
openings is
driven outwards between gaps between the discs and towards the outlet,
wherein the size of the central opening of the discs vary with axial position,
the discs with a larger central opening being positioned towards the inlet.
[0010] Each pumping stage may comprise a respective inlet and outlet.
[0011] The inlet may be configured to receive fluid in a direction aligned
with (e.g.
parallel to) the rotation axis. The outlet may be configured to direct fluid
in a direction
aligned with (e.g. parallel to) the rotation axis.
[0012] The disc impeller may comprise disc mounts configured to connect the
discs
together, the disc mounts being aligned with the rotation axis and being
circumferentially elongated.
[0013] The discs in each pumping stage may lie parallel to each other.
[0014] The discs in each pumping stage may be rigid.
[0015] Each stage may be separated by one or more components which directs
fluid
from the outer extent of the discs in one stage to the central openings of the
next
stage.
[0016] The disc impeller may comprise disc mounts configured to connect the
discs
together, the disc mounts being positioned towards the inlet and/or the
central axis.
[0017] The disc impeller may be of unitary construction.
[0018] The disc impeller may be formed from a single block of metal.
- 2 -
CA 03159329 2022-04-27
WO 2021/102583
PCT/CA2020/051626
[0019] The disc impeller may be formed by additive manufacturing techniques
(e.g.
3D printing or sintering).
[0020] The disc impeller may be formed by subtractive manufacturing techniques
(e.g. CNC machining).
[0021] The disc impeller may be formed from steel.
[0022] The spacing between successive discs (e.g. the opposing surfaces of two
neigbouring discs) may be between 2-20 mm.
[0023] Each disc may extend radially away from, and be concentric with, the
rotation
axis.
[0024] The surface of each disc may lie between the rotation axis and a plane
perpendicular to the rotation axis which intersects the rotation axis and the
side of the
disc closest to the inlet. The surface of each receiving disc may form an a
frustoconical shape.
[0025] Each disc may have an outer extent, and wherein the size of the outer
extent
of the discs may vary with axial position, the discs with a larger outer
extent being
positioned towards the inlet.
[0026] Each disc may form an outlet gap with the housing, wherein the size of
the
outlet gaps of the discs varies with axial position, the discs with a smaller
outlet gap
being positioned towards the inlet.
[0027] At least one of the discs may be connected to the shaft indirectly via
another
of the discs. At least one of the discs may not be connected to the shaft
directly (e.g.
with an armature connecting the disc to the shaft).
[0028] The inner surface of the discs around the central opening may be angled
inwardly away from the inlet.
[0029] Each stage may have between 2 and 12 discs.
[0030] The disc closest to the inlet may comprise a lip, the lip being
configured to
prevent fluid passing from the inlet directly into space between a planar
surface of
the disc closest to the inlet and the housing.
[0031] Each pumping stage may comprise a stator configured to draw liquid from
the
housing inwardly towards the rotation axis.
- 3 -
CA 03159329 2022-04-27
WO 2021/102583
PCT/CA2020/051626
[0032] According to a further aspect, there is provided a method of pumping
liquid
comprising:
placing a liquid pump as described herein such that liquid is in fluid
communication with the inlet; and
rotating the shaft.
[0033] The liquid may contain solid particulates.
[0034] The liquid may comprise oil.
[0035] The pump may comprise more than 10 stages. The pump may comprise up to
200 stages.
[0036] The discs may have an outside diameter of between 50 to 350 mm.
[0037] The axial dimension of each stage may be between 30-100 mm.
[0038] The pump may be configured to operate between 2500-5000 rpm.
[0039] The pump may be configured to provide a pumping rate of between 100 and
1,000 m3/day. The pump may be configured to provide a pumping rate of up to
10,000 m3/day.
[0040] The pump may be configured to pump oil, water or a mixture of the two
(e.g.
an emulsion).
[0041] The pump may be configured to pump one or more of the following:
= Light crude oil having an API gravity higher than 31.1 (i.e., less than
870
kg/m3);
= Medium oil having an API gravity between 22.3 and 31.1 (i.e., 870 to 920
kg/m3); and
= Heavy crude oil having an API gravity below 22.3 (i.e., 920 to 1000
kg/m3).
[0042] The pump may be configured to pump fluids containing up to 5% solids by
volume. The pump may be configured to pump fluids containing up to 40% solids
by
volume.
[0043] The impeller, shaft and/or other rotating components may be symmetric
about
at least one mirror plane aligned with the rotation axis. This may help enable
the
pump to run smoothly.
- 4 -
CA 03159329 2022-04-27
WO 2021/102583
PCT/CA2020/051626
[0044] A stator may be a stationary component (e.g. fixed with respect to the
housing) configured to direct fluid flow from the outside of the housing
towards a
centrally located axial outlet. The stator may comprise one or more blades.
[0045] The pump may be used downhole to extract fluid from a well; to remove
water
and/or oil from an oil well; to manage brine and other fluids within a salt
dome; and/or
to move fluid within a geothermal well.
[0046] The pump may be used in oil production which uses particulates (e.g.
sand).
One example is cold heavy oil production with sand (CHOPS) which involves
introducing sand during the completion procedure, maintenance of sand influx
during
the productive life of the well, and implementation of methods to separate the
sand
from the oil for disposal. The sand is then produced along with oil, water,
and gas
and then separated.
BRIEF DESCRIPTION OF THE DRAWINGS
[0047] Various objects, features and advantages of the invention will be
apparent
from the following description of particular embodiments of the invention, as
illustrated in the accompanying drawings. The drawings are not necessarily to
scale,
emphasis instead being placed upon illustrating the principles of various
embodiments of the invention. Similar reference numerals indicate similar
components.
Figure la is an axial cross-section of an embodiment of a pump.
Figure lb is a transverse cut-through view looking down from A-A as shown
in figure la.
Figure lc is a side view of the impeller stage of the embodiment of figure la.
Figure 2 is a perspective cut-through view of multiple stages of an
embodiment of a pump.
Figure 3 is a profile of an impeller for an embodiment of a pump.
DETAILED DESCRIPTION
Introduction
[0048] Pumps are typically used in the industry (e.g. the oil industry) to
pump liquids.
Often these liquids will contain solids (e.g. sand or rock fragments) which
can
damage pump components. For example, solids could damage seals by getting
between the components which are contacting each other (e.g. the vanes and the
- 5 -
CA 03159329 2022-04-27
WO 2021/102583
PCT/CA2020/051626
housing in a vane pump), or by impacting moving components (e.g. the impeller
in a
centrifugal pump).
[0049] Tesla turbine pumps may help address some of these issues. A Tesla
turbine
pump uses the boundary layer effect to transfer energy from a series of blades
to a
fluid (e.g. a liquid). As a result of this effect, the fluid follows a rapidly
accelerated
spiral path along the disc faces until it reaches a suitable exit. The
boundary layer is
formed through a combination of the fluid's adhesion and viscosity. The
boundary
layer helps isolate the discs from the fluid, and any contained solids, moving
through
the pump.
[0050] The present technology relates to ensuring that the fluid can move more
easily though the impeller stage while limiting the damage on the moving
component
of the pump.
[0051] Various aspects of the invention will now be described with reference
to the
figures. For the purposes of illustration, components depicted in the figures
are not
necessarily drawn to scale. Instead, emphasis is placed on highlighting the
various
contributions of the components to the functionality of various aspects of the
invention. A number of possible alternative features are introduced during the
course
of this description. It is to be understood that, according to the knowledge
and
judgment of persons skilled in the art, such alternative features may be
substituted in
various combinations to arrive at different embodiments of the present
invention.
Pump Stage
[0052] Figure la-c are various views of one stage of an embodiment of a Tesla
turbine pump. Figure la is an axial cross-section through the pump in a plane
aligned
with the pump axis. Figure lb is a transverse cut-through view looking down
from A-
A (shown in figure la). Figure lc is a side view of the impeller stage.
[0053] In this case, the pump comprises:
a housing 101 having an inlet 103 disposed at an upstream end and an outlet
104 disposed at a downstream end opposite the inlet;
a shaft 105 extending through the housing along a center axis 120 of the
housing and configured to be rotated about a rotation axis by a motor (not
shown);
and
- 6 -
CA 03159329 2022-04-27
WO 2021/102583
PCT/CA2020/051626
one or more pumping stages connected along the shaft in a co-axial
arrangement, each pumping stage comprising a disc impeller comprising multiple
axially spaced discs 102a-d, each disc having a central opening such that when
the
disc impeller is rotated, liquid enters the disc impeller through the central
openings
and is driven outwards between gaps between the discs and towards the outlet,
wherein the size of the central opening of the discs vary with axial position,
the discs with a larger central opening being positioned towards the inlet.
[0054] In addition to the receiver discs 102a-d which have central openings
for
receiving fluid from the inlet axially and redirecting the received fluid
laterally, the disc
impeller also includes a blocking disc 102e. The blocking disc is positioned
furthest
away from the inlet and does not have any central opening for receiving fluid.
This
means that any fluid which is not redirected by the first receiving discs 102a-
d will be
redirected laterally by the blocking disc. All of the discs in this case
extend radially
and concentrically away from the rotation axis.
[0055] It will be appreciated that for designs which the central openings do
not
diminish in size as you move away from the inlet, when fluid being pumped into
the
inlet, there may be turbulence when the flow strikes an component which does
not
permit any through flow (such as a moving blocking disc or a stationary part
of the
housing). In this case, the diminishing size of the central openings may help
each
disc to redirect a portion of the flow, thereby leading to improved laminar
flow. This is
particularly important where the fluid contains solids because laminar flow
may help
ensure that the solids do not come into contact with solid components of the
pump.
[0056] In this case, the pump also comprises an optional stator before the
outlet.
This stator is configured to redirect rotationally flowing liquid at the edges
of the
housing inwards towards the centrally located outlet. Because the stator is
not
configured to move, it can be built more robustly because excess weight in
this
component may not cause an increased power demand on the motor driving the
impeller stage.
[0057] Having the inlet and the outlet centrally located allows a composite
pump to
be formed by multiple stages arranged coaxially.
[0058] In this case, as shown in figures lb-1c the disc impeller comprises
disc
mounts 107aa-ab, 107ba-bb, 107ca-cc, 107da-db configured to connect the discs
- 7 -
CA 03159329 2022-04-27
WO 2021/102583
PCT/CA2020/051626
together, the disc mounts being aligned with the rotation axis and being
circumferentially elongated.
[0059] In this case, the receiver discs 102a-d are not directly connected to
the shaft.
Instead, the disc towards the outlet 102e is directly connected to the shaft.
Each disc
closer to the inlet is connected to its neighbor towards the outlet. For
example, disc
102d is connected to disc 102e; disc 102c is connected to disc 102d and so on.
That
is, at least one of the discs is supported only via the mounts connecting the
disc to
one or more neighbouring discs. Avoiding the direct connection to the shaft
may help
reduce turbulence by reducing the blockages within the central channel formed
by
the central openings.
[0060] In this case, as shown in figure 1 b, the mounts 107ca-cc are
circumferentially
elongated. That is, they have a greater dimension along a circumference around
the
rotation axis than along a radius from the rotation axis. Although this
reduces the
space for fluid passing out from the central channel, the elongated shape
reduces the
potential for impact between the relatively stationary fluid and the moving
mounts,
while providing the required structural rigidity. The mounts are positioned
towards the
central channel so that the fluid can apply a corrective force in the event
that the
discs deviate away from a plane perpendicular to the rotation axis.
[0061] In this case, the disc impeller is of unitary construction. In this
case, the shaft
and discs are formed using a single block of steel using subtractive method
such as
using a CNC (computer numerical control) machine. In this case, the CNC
machine
is configured to remove material from the block.
[0062] In this case, the spacing between opposing surfaces of neighbouring
discs
(i.e. corresponding to the gap through which liquid can flow) is between 0.5-
20 mm.
This may permit smooth flow of viscous liquids such as oil which may contain
particulates. The spacing between opposing surfaces of neighbouring discs may
be
between 10% and 40% of the discs in the stage (i.e. between the top of the
uppermost disc and the bottom of the lowermost disc).
[0063] In this case, each disc has an outer extent, wherein the size of the
outer
extent of the discs does not vary with axial position. It will be appreciated
that other
configurations are possible.
- 8 -
CA 03159329 2022-04-27
WO 2021/102583
PCT/CA2020/051626
Multiple-Stage Embodiment
[0064] Figure 2 is a transverse cut-through perspective view of multiple
stages of a
pump.
[0065] In this case, the pump comprises:
a housing 201' having an inlet 203' disposed at an upstream end and an
outlet 104 disposed at a downstream end opposite the inlet;
a shaft (not shown) extending through the housing along a center axis of the
housing and configured to be rotated about a rotation axis by a motor (not
shown);
and
multiple pumping stages 290, 290', 290" connected along the shaft in a co-
axial arrangement, each pumping stage comprising a disc impeller comprising
multiple axially spaced discs 202'a-c each disc having a central opening such
that
when the disc impeller is rotated, liquid enters the disc impeller through the
central
openings and is driven outwards between gaps between the discs and towards the
outlet,
wherein the size of the central opening of the discs vary with axial position,
the discs with a larger central opening being positioned towards the inlet.
[0066] The pump is configured such that each impeller stage has a
corresponding
housing module. The connected housing modules make up the housing.
[0067] In this case, each stage of the pump comprises complementary connectors
on the upstream end and on the downstream end of housing modules. This means
that a series of identical stages can be connected end on end to form a pump
with
multiple stages. The outlet of one stage 290 is configured to direct liquid
into the inlet
203' of a connecting neighbouring stage 290'.
[0068] In addition to the receiver discs 202'a-c which have central openings
for
receiving fluid from the inlet and redirecting the received fluid laterally,
the disc
impeller also includes a blocking disc 202'd. The blocking disc is positioned
furthest
away from the inlet and does not have any central opening for receiving fluid.
This
means that any fluid which is not redirected by the first receiving discs
202'a-c will be
redirected laterally by the blocking disc. All of the discs in this case
extend radially
and concentrically away from the rotation axis.
- 9 -
CA 03159329 2022-04-27
WO 2021/102583
PCT/CA2020/051626
[0069] It will be appreciated that the components of the impeller configured
to
contribute to pumping the fluid are rotationally symmetric. This may help
ensure
smooth operation of the pump by improving the balance. It may also allow the
pump
to be operated across a wide range of speeds. For example, a pump comprising a
conventional centrifugal impeller may only operate in a narrow range of
speeds.
[0070] The inner surface of the housing adjacent to the outside edge of the
discs
may be rotationally symmetric. This may allow the pump to be more easily
manufactured and ensure a consistent flow from the discs to the outlet.
[0071] Unlike the embodiment of figure la, in this case, the receiving disc
202'a
which is closest to the inlet 203' comprises a lip 231' which engages with the
housing
of the neighbouring stage 290". This lip is configured to rotate with respect
to the
stationary inlet channel about the rotation axis. This lip is configured to
direct water
passing from the inlet 203' into spaces between the planar surfaces of two
rotating
discs rather than into a space between the planar surface of the receiving
disc 202'a
towards the inlet and the housing. This may help ensure that the fluid from
the inlet is
accelerated consistently as all the fluid will pass between two rotating
discs.
[0072] The disc closest to the outlet also comprises an engagement member
232', in
this case to engage with a complementary connector in the housing of the next
stage. The engagement member 232' may help with alignment. In this case, the
engagement is ring shaped to facilitate rotation about the rotation axis.
[0073] It will be appreciated that for designs which the central openings do
not
diminish in size as you move away from the inlet, when fluid being pumped into
the
inlet, there may be turbulence when the flow strikes an object which does not
permit
any through flow (such as a moving blocking disc or a stationary part of the
housing).
In this case, the diminishing size of the central openings may help each disc
to
redirect a portion of the flow, thereby leading to improved laminar flow. This
is
particularly important where the fluid contains solids and laminar flow may
help
ensure that the solids do not come into contact with solid components of the
pump.
Reducing turbulence on the inlet side may be important in a multistage pump
where
fluid is being pumped into the inlet of each subsequent stage by the preceding
pump
stages (e.g. as opposed to being sucked in by the discs as may be the case in
a
single stage arrangement).
[0074] In this case, the inlet 203' and the outlet 204' are both centrally
located which
allows a composite pump to be formed by multiple stages arranged coaxially. It
will
- 10-
CA 03159329 2022-04-27
WO 2021/102583
PCT/CA2020/051626
be appreciated that any number of stages could be combined together (e.g. up
to
100 stages or more).
[0075] Although not shown, the impellers of the embodiment of figure 2
comprises
disc mounts configured to connect the discs together, the disc mounts being
aligned
with the rotation axis and being circumferentially elongated.
[0076] In this case, the receiver discs 202'a-c are not directly connected to
the shaft.
Instead, the disc towards the outlet 202'd is directly connected to the shaft.
Each disc
closer to the inlet is connected to its neighbor towards the outlet. For
example, disc
202'c is connected to disc 202'd; disc 202'b is connected to disc 202'c and so
on.
Avoiding the direct connection to the shaft may help reduce turbulence by
reducing
the blockages within the central channel formed by the central openings.
[0077] In this case, as shown in figure 1 b, the mounts are circumferentially
elongated. That is, they have a greater dimension along a circumference around
the
rotation axis than along a radius from the rotation axis. Although this
reduces the
space for fluid passing out from the central channel, the elongated shape
reduces the
potential for impact between the relatively stationary fluid and the moving
mounts,
while providing the required structural rigidity. The mounts are positioned
towards the
central channel so that the fluid can apply a corrective force in the event
that the
discs deviate away from a plane perpendicular to the rotation axis.
[0078] In this case, the disc impeller is of unitary construction. The shaft
connector
239' and discs are formed using a single block of steel using a CNC (computer
numerical control) machine. In this case, the CNC machine is configured to
remove
material from the block. In this case, each stage has a shaft connector 239'
comprising a hollow closed channel through which the shaft can pass.
[0079] In this case, the spacing between opposing surfaces of successive discs
is
between 2-20 mm.
[0080] In this case, to further direct the fluid towards the gaps between the
rotating
discs, the inner surface of the discs around the central opening are angled
inwardly
away from the inlet. This may help direct the fluid flow which is not passing
between
the discs to be directed towards other discs while reducing turbulence.
[0081] On the outer extent of the discs, some turbulence may be mitigated by
configuring the stage such that each disc forms an outlet gap with the
housing, and
wherein the size of the outlet gaps of the discs vary with axial position, the
discs with
- 11 -
CA 03159329 2022-04-27
WO 2021/102583
PCT/CA2020/051626
a smaller outlet gap being positioned towards the inlet. In this case, the
increasing
gap is provided by the discs having the same diameter and the housing
increasing in
diameter away from the inlet and towards the outlet. This means that as fluid
is
added from the gaps between each successive disc, there is more room for this
additional fluid to be accommodated.
[0082] In other embodiments, providing a larger gap for fluid exiting the
impeller
towards the outlet side may be provided by the size of the outer extent of the
discs
varying with axial position, the discs with a larger outer extent being
positioned
towards the inlet.
Impeller Profile
[0083] Figure 3 shows a profile for an impeller for a pump stage. The impeller
is
similar to that of figure 2. The impeller stage would be formed by rotating
this profile
about the rotation axis. Mounts are not shown.
[0084] The disc impeller comprises multiple axially spaced discs 302a-c each
disc
having a central opening such that when the disc impeller is rotated, liquid
enters the
disc impeller through the central openings and is driven outwards between gaps
between the discs and towards the outlet, wherein the size of the central
opening of
the discs vary with axial position, the discs with a larger central opening
being
positioned towards the inlet.
[0085] In addition to the receiver discs 302a-c which have central openings
for
receiving fluid from the inlet and redirecting the received fluid laterally,
the disc
impeller also includes a blocking disc 302d. The blocking disc is positioned
furthest
away from the inlet and does not have any central opening for receiving fluid.
This
means that any fluid which is not redirected by the first receiving discs 302a-
c will be
redirected laterally by the blocking disc. All of the discs in this case
extend radially
and concentrically away from the rotation axis.
[0086] In this case, the receiving disc 302a which is closest to the inlet 303
comprises a lip 331 which engages with the housing of the neighbouring stage.
This
lip is configured to direct water passing from the inlet 303 into spaces
between the
planar surfaces of two rotating discs rather than into a space between the
planar
surface of the receiving disc 302a towards the inlet and the housing. This may
help
ensure that the fluid from the inlet is accelerated consistently as all the
fluid will pass
between two rotating discs.
- 12-
CA 03159329 2022-04-27
WO 2021/102583
PCT/CA2020/051626
[0087] The disc closest to the outlet also comprises an engagement member 332,
in
this case to engage with a complementary connector in the housing of the next
stage. In this case, the engagement is ring shaped to facilitate rotation
about the
rotation axis.
[0088] In this case, the stage has a shaft connector 339 comprising a hollow
closed
channel through which the shaft can pass.
Other Options
[0089] In other embodiments, the surface of the disc may lie between the
rotation
axis and a plane perpendicular to the rotation axis. That is, the surface of
each
receiving disc may form an a frustoconical shape. The frustoconical shape may
be
configured such that the outer extent of the disc is axially further away from
the inlet
than the inner extent of the disc.
[0090] The mounts may be configured to be angled inwardly between the outsides
of
the central openings of the two connected discs. This may help reduce
turbulence
and/or reduce wear on the discs by ensuring that the area of the discs inside
the
mounts is reduced. It will be appreciated that having a rotating disc surface
inside the
mount may drive a portion of the fluid into the disc.
[0091] Although the present invention has been described and illustrated with
respect to preferred embodiments and preferred uses thereof, it is not to be
so
limited since modifications and changes can be made therein which are within
the
full, intended scope of the invention as understood by those skilled in the
art.
- 13-
