Note: Descriptions are shown in the official language in which they were submitted.
CA 02258426 1999-O1-08
Title: PRANDTL LAYER TURBINE
FIELD OF THE INVENTION
This invention relates to an apparatus used to transmit
motive force between a fluid and a plurality of spaced apart rotatable
members. The apparatus may be used to transmit the motive force
from a fluid to the spaced apart members or, alternately, from the
spaced apart members to the fluid.
BACKGROUND OF THE INVENTION
Prandtl layer turbines were first described by Nikola Tesla
in United States Patent No. 1,061,206 (Tesla). For this reason, these
turbines are sometimes referred to as "Tesla Turbines". Figures 1 and 2
show the design for a prandtl layer turbine as disclosed in Tesla. As
15 disclosed by Tesla, a prandtl layer turbine 10 comprises a plurality of
discs 12 which are rotatably mounted in a housing 14. Housing 14
comprises ends 16 and ring 18 which extends longitudinally between
ends 16. Discs 12 are spaced apart so as to transmit motive force
between a fluid in housing 14 and rotating discs 12.
20 The discs 12, which are flat rigid members of a suitable
diameter, are non-rotatably mounted on a shaft 20 by being keyed to
shaft 20 and are spaced apart by means of washers 28. The discs have
openings 22 adjacent to shaft 20 and spokes 24 which may be
substantially straight. Longitudinally extending ring 18 has a diameter
25 which is slightly larger than that of discs 12. Extending between
opening 22 and the outer diameter of disc 12 is the motive force
transfer region 26.
The transfer of motive force between rotating discs 12 and
a fluid is described in Tesla at column 2, lines 30 - 49. According to this
30 disclosure, fluid, by reason of its properties of adherence and viscosity,
upon entering through inlets 30, and coming into contact with
rotating discs 12, is taken hold of by the rotating discs and subjected to
two forces, one acting tangentially in the direction of rotation and the
CA 02258426 1999-O1-08
_2_
other acting radially outwardly. The combined effect of these
tangential and centrifugal forces is to propel the fluid with
continuously increasing velocity in a spiral path until it reaches a
suitable peripheral outlet from which it is ejected.
Conversely, Tesla also disclosed introducing pressurized
fluid via pipes 34 to inlets 32. The introduction of the pressurized fluid
would cause discs 12 to rotate with the fluid travelling in a spiral path,
with continuously diminishing velocity, until it reached central
opening 22 which is in communication with inlet 30. Motive force is
transmitted by the pressurized fluid to discs 12 to cause discs 12 to
rotate and, accordingly, shaft 20 to rotate thus providing a source of
motive force.
Accordingly, the design described in Tesla may be used as a
pump or as a motor. Such devices take advantage of the properties of a
fluid when in contact with the rotating surface of the discs. If the discs
are driven by the fluid, then as the fluid passes through the housing
between the spaced apart discs, the movement of the fluid causes the
discs to rotate thereby generating power which may be transmitted
external to the housing via a shaft to provide motive force for various
applications. Accordingly, such devices function as a motor.
Conversely, if the fluid in the housing is essentially static, the rotation
of the discs will cause the fluid in the housing to commence rotating
in the same direction as the discs and to thus draw the fluid through
the housing, thereby causing the apparatus to function as a pump or a
fan. In this disclosure, all such devices, whether used as a motor or as a
pump or fan, are referred to as "prandtl layer turbines" or "Tesla
turbines".
Various designs for prandtl layer turbines have been
developed. These include those disclosed in United States Patent No.
4,402,647 (Effenberger), United States Patent No. 4,218,177 (Robel),
United States Patent No. 4,655,679 (Giacomel), United States Patent No.
CA 02258426 1999-O1-08
-3-
5,470,197 (Cafarelli) and United States Reissue Patent No. 28,742
(Rafferty et al). Most of these disclosed improvements in the design of
a Tesla turbine. However, despite these improvements, Tesla turbines
have not been commonly used in commercial environment.
SUMMARY OF THE INVENTION
In accordance with the instant invention, there is
provided an apparatus comprising:
(a) a longitudinally extending housing having a fluid inlet
port;
(b) at leat one plurality of spaced apart members rotatably
mounted in the housing to transmit motive force between
fluid introduced through the fluid inlet port and the
members, the spaced apart members having an upstream
end and a downstream end; and,
(c) a fluid outlet port extending longitudinally along the
housing and having a first end positioned towards the
upstream end of the spaced apart members and a second
end positioned towards the downstream end of the spaced
apart members, the second end of the fluid outlet port
radially displaced along the housing from the first end.
In one embodiment, the outlet extends in a spiral between
the first and second ends.
In another embodiment, the first end is adjacent the
25 upstream end of the spaced apart members and the second end is
adjacent the downstream end of the spaced apart members.
In another embodiment, the second end is radially
displaced from the first end in the direction of rotation of the spaced
apart members.
30 In another embodiment, the apparatus comprises a first
plurality of spaced apart members and a second plurality of spaced
CA 02258426 1999-O1-08
-4-
apart members. The second plurality of spaced apart members may be
positioned in series with the first plurality of spaced apart membersor
at least partially nested within, or fully nested within, the first
plurality of spaced apart members.
In another embodiment, each of the members comprises a
thin disc.
In accordance with the instant invention, there is also
provided a prandtl layer turbine comprising a housing having a
longitudinally extending fluid outlet port, the fluid outlet port having
10 spaced apart first and second ends, the second end of the fluid outlet
port radially displaced along the housing from the first end.
In one embodiment, the prandtl layer turbine comprises a
plurality of rotatably mounted spaced apart members and the second
end is radially displaced from the first end in the direction of rotation
15 of the spaced apart members.
In accordance with the instant invention, there is also
provided an apparatus comprising:
(a) a longitudinally extending housing having a means for
permitting a fluid to enter the housing;
20 (b) a plurality of spaced apart means for transmitting
motive force between fluid introduced through the means
for permitting a fluid to enter the housing and the spaced
apart means, each spaced apart means having a pair of
opposed surfaces whereby the fluid passing over the
25 surface forms a boundary layer which delaminates as it
passes over the surface; and,
(c) means for discharging the fluid from the housing at
radially displaced locations around the housing.
In one embodiment, at least some of the radially displaced
30 locations are longitudinally displaced from each other and may be
positioned to define a spiral along the housing. The radially displaced
CA 02258426 1999-O1-08
-5-
locations may be discrete fluid exit ports along the housing or they
may define a continuous spiral along the housing.
In accordance with the instant invention, there is also
provided a method for transmitting motive force between a fluid and
a plurality of spaced apart members comprising:
(a) introducing the fluid into a longitudinally extending
housing having at least one plurality of spaced apart
members rotatably mounted in the housing;
(b) passing the fluid through the at least one plurality of
spaced apart members to form a boundary layer which
passes over the at least one plurality spaced apart
members; and,
(c) discharging the fluid at radially displaced locations
along the housing.
In one embodiment, at least some of the radially displaced
locations are longitudinally displaced from each other and the method
further comprises passing a portion of the fluid through the spaced
apart members while a portion of the fluid is discharged through some
of the radially displaced locations.
In another embodiment, at least some of the radially
displaced locations are longitudinally displaced from each other and
the method further comprises passing portions of the fluid between
adjacent spaced apart members and discharging each such portion of
the fluid through a radially displaced location which is longitudinally
positioned adjacent the longitudinal position of the fluid when it exits
from between the spaced apart members.
In another embodiment, the radially displaced locations
are radially displaced from each other in the direction of rotation of
the spaced apart members.
In another embodiment, the at least one plurality of
spaced apart members comprises first and second distinct spaced apart
CA 02258426 1999-O1-08
-6-
members and the method further comprises passing the fluid through
the second spaced apart members to form a boundary layer which
passes over the second spaced apart members.
In another embodiment, the first and second distinct
5 spaced apart members are positioned in series and the method
comprises passing the fluid through the first spaced apart members
and then through the second spaced apart members.
In another embodiment, the first spaced apart members
are positioned are position at least partially within the second spaced
10 apart members and the method comprises passing a portion of the
fluid through some of the second spaced apart members while another
portion of the fluid is passing through some of the second spaced apart
members.
In another embodiment, the fluid passes radially
15 outwardly from the first spaced apart members to the second spaced
apart members.
In another embodiment, the spaced apart members rotate
as the fluid passes therethrough and the method further comprises
rotating the first spaced apart members at a greater rotational speed
20 than the second spaced apart members.
In another embodiment, wherein the spaced apart
members rotate as the fluid passes therethrough and the method
further comprises passing the fluid through the first and second spaced
apart members to rotate the first spaced apart members at a greater
25 rotational speed than the second spaced apart members.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other advantages of the instant invention will
be more fully and particularly understood in connection with the
30 following description of the preferred embodiments of the invention
in which:
CA 02258426 1999-O1-08
-7-
Figure 1 is a cross section along the line 1 - 1 in Figure 2 of
a prior art prandtl layer turbine;
Figure 2 is a cross section along the line 2 - 2 in Figure 1 of
the prior art prandtl layer turbine of Figure 1;
5 Figure 3 is a top plan view of a disc according to a first
preferred embodiment of the instant invention;
Figure 4a is an side elevational view of the disc of Figure
3;
Figures 4b - 4d are enlargements of area A of Figure 4a;
10 Figure 5 is a longitudinal cross section of a prandtl layer
turbine according to a second preferred embodiment of the
instant invention;
Figure 6 is a schematic drawing of the spaced apart
members of one of the prandtl layer turbine unit of Figure
15 5;
Figure 7 is a graph of suction and flow versus the ratio of
the inner diameter of a spaced apart member to the outer
diameter of the same spaced apart member;
Figure 8 is a longitudinal cross section of a prandtl layer
20 turbine according to a third preferred embodiment of the
instant invention;
Figure 9 is a longitudinal cross section of a prandtl layer
turbine according to a fourth preferred embodiment of the
instant invention;
25 Figure 10 is a longitudinal cross section of a prandtl layer
turbine according to a fifth preferred embodiment of the
instant invention;
Figure 11 is a longitudinal cross section of a prandtl layer
turbine according to a sixth preferred embodiment of the
30 instant invention;
Figure 12a is a longitudinal cross section of a prandtl layer
CA 02258426 1999-O1-08
_8_
turbine according to a seventh preferred embodiment of
the instant invention;
Figure 12b is a cross section along the line 12 - 12 in Figure
12a;
Figure 13 is a longitudinal cross section of a prandtl layer
turbine according to an eighth preferred embodiment of
the instant invention;
Figure 14 is a longitudinal cross section of a prandtl layer
turbine according to a ninth preferred embodiment of the
instant invention;
Figure 15 is an end view from upstream end 78 of the
prandtl layer turbine of Figure 14;
Figure 16 is a longitudinal cross section of a prandtl layer
turbine according to a tenth preferred embodiment of the
instant invention;
Figure 17 is an end view from upstream end 78 of the
prandtl layer turbine of Figure 16;
Figure 18 is a perspective view of a prandtl layer turbine
according to an eleventh preferred embodiment of the
instant invention;
Figure 19 is a further perspective view of the prandtl layer
turbine of Figure 18 wherein additional housing of the
outlet is shown;
Figure 20 is a perspective view of the longitudinally
extending ring of a prandtl layer turbine according to an
twelfth preferred embodiment of the instant invention;
Figure 21 is a transverse cross section along the line 21 - 21
of a prandtl layer turbine having the longitudinally
extending ring of Figure 20 wherein the turbine has
secondary cyclones in flow communication with the
turbine outlets;
CA 02258426 1999-O1-08
-9-
Figure 22 is longitudinal section of a vacuum cleaner
incorporating a prandtl layer turbine;
Figure 23 is a longitudinal section of a mechanically
coupled prandtl layer motor and a prandtl layer fan;
Figure 24 is a perspective view of a windmill
incorporating a prandtl layer turbine; and,
Figure 25 is a cross section along the line 25 - 25 of the
windmill of Figure 24.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
According to the instant invention, improvements to the
design of prandtl layer turbines are disclosed. These improvements
may be used in conjunction with any known designs of prandtl layer
turbines. Without limiting the generality of the foregoing, housing 14
15 may be of any particular configuration and mode of manufacture.
Further, the fluid inlet and fluid outlet ports may be of any particular
configuration known in the art and may be positioned at any
particular location on the housing which is known in the art. In
addition, while discs 12 are shown herein as being relatively thin, flat
20 members with a small gap 56 between the outer edge of the disc and
the inner surface of ring 18, it will be appreciated that they may be of
any particular design known in the art. For example, they may be
curved as disclosed in Effenberger and/or the distance between
adjacent discs may vary radially outwardly from shaft 20. Further, the
25 perimeter of discs 12 need not be circular but may be of any other
particular shape. Accordingly, discs 12 have also been referred to
herein as "spaced apart members".
Referring to Figures 3 and 4a-d, preferred embodiments
for spaced apart members 12 are shown. As shown in Figure 3, spaced
30 apart members 12 have an inner edge 40 and an outer edge 42. If spaced
apart member 12 has a central circular opening 22, then inner edge 40
CA 02258426 1999-O1-08
-10-
defines the inner diameter of spaced apart member 12. Further, if the
periphery of spaced apart member 12 is circular, then outer edge 42
defines the outer diameter of spaced apart member 12.
Spaced apart members 12 may extend at any angle form
5 shaft 20 as is known in the art and preferably extend at a right angle
from shaft 20. Further, spaced apart member 12 may have any
curvature known in the art and may be curved in the upstream or
downstream direction (as defined by the fluid flow through housing
14). Preferably, spaced apart member 12 is planer so as to extend
10 transversely outwardly from shaft 20. In this specification, all such
spaced apart members are referred to as extending transversely
outwardly from longitudinally extending shaft 20.
Each spaced apart member 12 has two opposed sides 44 and
46 which extend transversely outwardly from inner edge 40 to outer
15 edge 42. These surfaces define the motive force transfer region 26 of
spaced apart members 12. The spacing between adjacent spaced apart
members 12 may be the same or may vary as is known in the art.
Without being limited by theory, as a fluid travels across
motive force transfer region 26, the difference in rotational speed
20 between the fluid and spaced apart member 12 causes a boundary layer
of fluid to form adjacent opposed surfaces 44, 46. If the fluid is
introduced through openings 22, then the fluid will rotate in a spiral
fashion from inner edge 40 outwardly towards outer edge 42. At some
intermediate point, the fluid will have sufficient momentum that it
25 will separate from opposed surfaces 44, 46 (i.e. it will delaminate) and
travel towards the fluid exit port. By thickening the boundary layer, for
a given rotation of a spaced apart member 12, additional motive force
may be transferred between the rotating spaced apart member 12 and
the fluid. Thus the efficiency of the motive force transfer between
30 spaced apart members 12 and the fluid may be increased.
The boundary layer may be thickened for a particular
CA 02258426 1999-O1-08
-11-
opposed surface 44, 46 of a particular spaced apart member by
providing an area on that spaced apart member 12 having an increased
width (i.e. in the longitudinal direction) at at least one discrete location
of the particular opposed surface 44, 46. Preferably, a plurality of such
areas of increased width are provided on each opposed surface 44, 46 of
a particular spaced apart member 12. Further, preferably such areas of
increased width are provided on at least some, preferably a majority
and most preferably all of spaced apart members of turbine 10.
Referring to Figures 3 and 4, the discrete areas of increased
width may be provided by having raised portions 48 which are
positioned at any place on surface 44, 46. As shown in Figure 3, these
may be positioned on the inner portion of spaced apart member 12
such as adjacent inner edge 40 or spaced some distance outwardly from
inner edge 40. Raised portion 48 preferably is positioned on the inner
portion of spaced apart member 12. Further, a series of raised portions
48 may be sequentially positioned outwardly on spaced apart member
12 so as to successively thicken the boundary layer as it encounters a
plurality of raised areas 48.
Raised portion 48 is a discontinuity or increased width in
surface 44, 46 which the fluid encounters as it rotates around spaced
apart member 12. As the fluid passes over raised portion 48, the
boundary layer thickens. By passing the fluid over a series of raised
portions, the boundary layer may be continuously thickened. This is
advantageous as the thicker the boundary layer, the more energy is
transferred between the rotating spaced apart members and the fluid.
Side 50 of raised portion 48 may extend generally
perpendicular to surface 44, 46 (eg. raised portion 48 may be a generally
square or rectangular protuberance as shown in Figure 4b) at an obtuse
angle alpha (eg. 102 - 122°) to surface 44, 46 (eg. raised portion 48
may be
a generally triangular protuberance as shown in Figure 4c), or a
rounded member on surface 44, 46 (eg. raised portion 48 may be a
CA 02258426 1999-O1-08
-12-
generally hemispherical protuberance as shown in Figure 4c). Raised
portion 48 may be constructed as a point member so as to be positioned
at a discrete location on surface 44, 46. Alternately, it may extend for an
indefinite length as shown in Figure 3.
5 Side 50 is preferably positioned such that the direction of
travel of the fluid as it encounters side 50 is normal to side 50. As the
travels outwardly over surface 44, 46, it will be subjected to both
tangential and radial acceleration as shown by arrows T and R in figure
3. Generally, these forces will cause the fluid to travel outwardly at an
10 angle of about 40° to the radial as shown in Figure 3. By
positioning
side 50 at such an angle (eg. 30° to 50°), the direction of
travel of the
fluid as it encounters side 50 will be about 90°.
Raised portion 48 may have a vertical height from surface
44, 46 varying from about 0.5 to about 25, preferably from about 0.5 to
15 about 10 and more preferably 0.5 to about 2 of the thickness of the
boundary layer immediately upstream of raised portion 48.
The boundary layer may be delaminated from a particular
opposed surface 44, 46 of a particular spaced apart member 12, or the
delamination of the boundary layer from a particular opposed surface
20 44, 46 of a particular spaced apart member 12, may be assisted by
providing an area on that spaced apart member 12 having an increased
width (i.e. in the longitudinal direction) at at least one discrete location
of the particular opposed surface 44, 46. Preferably, a plurality of such
areas of increased width are provided on each opposed surface 44, 46 of
25 a particular spaced apart member 12. Further, preferably such areas of
increased width are provided on at least some, preferably a majority
and most preferably all of spaced apart members of turbine 10.
Referring to Figures 3 and 4a-4d, such discrete areas of
increased width may be provided by having raised portions 52 which
30 are positioned on surface 44, 46. As shown in Figure 3, these may be
positioned on the outer portion of spaced apart member 12 such as
CA 02258426 1999-O1-08
-13-
adjacent outer edge 42 or spaced some distance inwardly from outer
edge 42.
As the fluid travels over opposed surface 44, 46, it
encounters raised portion 52. This results in, or assists in, the
5 delamination of the boundary layer from opposed surface 44, 46. If the
fluid has not delaminated from opposed surface 44, 46 when it reaches
outer edge 42 then the delamination process will absorb energy from
the prandtl layer turbine thereby reducing the overall efficiency of the
prandtl layer turbine.
10 Raised portions 52 may be positioned adjacent outer edge
42 or at an intermediate position inwardly thereof as shown in Figure
3. Further, as with raised portion 48, raised portion 52 preferably has an
upstream side 54 which is a marked discontinuity to opposed surface
44, 46. As shown in Figure 4a, side 54 extends longitudinally outwardly
15 from surface 44, 46. However, raised portions 52 may have the same
shape as raised portions 48.
As fluid travels radially outwardly between inner edge 40
and outer edge 42, a boundary layer is produced (with or without
raised portions 48) which thickens as the boundary layer moves
20 radially outwardly from shaft 20. Preferably, at least one raised portion
54 is positioned radially outwardly on opposed surface 44, 46.
Preferably, raised portion 52 may be positioned at any point on surface
44, 46 where it is desired to commence the delamination process.
Typically, the fluid will commence to delaminate at a position where
25 the fluid has a velocity of about 103 to about 105 mach. Accordingly,
raised portion 52 is positioned adjacent such a position and preferably
just upstream of where the fluid reaches about 103 mach. This velocity
corresponds to the region where the boundary layer achieves fluid
flow characteristics which but for raised portion 52 would cause the
30 fluid to delaminate.
Raised portion 52 may have a vertical height from surface
CA 02258426 1999-O1-08
-14-
44, 46 varying from about 1 to about 100, preferably from about 1 to
about 25 and more preferably 1 to about 5 of the thickness of the
boundary layer immediately upstream of raised portion 52.
In another embodiment, any of the spaced apart members
12 may include both one or more raised areas 48 to assist in thickening
the boundary layer and one or more raised areas 52 to assist in the
delamination of the boundary layer.
In the specification, the word "fluid" is used to refer to
both liquids and gases. In addition, due to the formation of a boundary
layer adjacent opposed surfaces 44, 46, the fluid may include solid
material since the formation of the boundary layer results in a
reduction of, or the prevention of, damage to the surface of spaced
apart members 12 by abrasion or other mechanical action of the solid
material. For this reason, spaced apart members 12 may be made from
any materials known in the art including plastic, metal, such as
stainless steel, composite material such as KevlarTM and reinforced
composite materials such as carbon fibre or metal mesh reinforced
KevlarTM.
In a further preferred embodiment of the instant
invention, one or more fan members 68, 70 may be provided to assist
in the movement of air through the prandtl layer turbines (see for
example Figure 5). This figure also shows a further alternate
embodiment in which two prandtl layer turbines units 64, 66, each of
which comprises a plurality of discs 12, are provided in a single
housing 14. Each prandtl layer turbine unit 64, 66 is provided with an
inlet 60 having a single outlet 62. Discs 12 of each prandtl layer turbine
64, 66 are mounted on a common shaft 20. This nartic-ular
embodiment may advantageously be used to reduce the pressure drop
through the prandtl layer turbine. For example, instead of directing all
of the fluid at a set number of spaced apart members 12, half of the
fluid may be directed to one half of the spaced apart members (prandtl
CA 02258426 1999-O1-08
-15-
layer turbine unit 64) and the other half may be directed at another set
of spaced apart members (prandtl layer turbine unit 66). Thus the
mean path through the prandtl layer turbine is reduced by half
resulting in a decrease in the pressure loss as the fluid passes through
5 prandtl layer turbine 10. In the embodiment of Figure 5, the fluid feed
is split in two upstream of housing 14 (not shown). Alternately, as
shown in Figures 10 and 11, all of the fluid may be fed to a single inlet
60 which is positioned between prandtl layer turbine units 64, 66.
While in these embodiments a like number of similar spaced apart
10 members 12 have been included in each prandtl layer turbine unit 64,
66, each turbine unit 64, 66 may incorporate differing number of spaced
apart members 12 and/or differently configured spaced apart members
12.
It will be appreciated that discs 12 of prandtl layer turbine
15 unit 64 may be mounted on a first shaft 20 and discs 12 of the second
prandtl layer turbine unit 66 may be mounted on a separate shaft 20
(not shown). This alternate embodiment may be used if the two shaft
are to be rotated at different speeds. This can be advantageous if the
prandtl layer turbine is to be used to as a separator as discussed below.
20 If spaced apart members 12 are of the same design, then the different
rotational speed of spaced apart members 12 will impart different flow
characteristics to the fluid and this may beneficially be used to separate
the fluid (or particles entrained into the fluid) into different fluid
streams, each of which has a different composition.
25 Fan member 68 may be of any particular construction that
will transport, or will assist in transporting, fluid to opening 22 of
spaced apart member 12. Similarly, fan member 70 may be of any
particular construction that will assist in the movement of fluid
through unit 64, 66 and transport it, or assist in transporting it, to an
30 outlet 62. Fan member 68 acts to pressurize the fluid and to push it
downstream to one or more of spaced apart members 12. Conversely,
CA 02258426 1999-O1-08
-16-
fan member 70 acts to create a low pressure area to pull the fluid
downstream, either through downstream spaced apart members 12 or
through outlet 62. Fan member 70 may optionally be positioned
outside of the interior of ring 18 so as to draw the fluid from housing
14. Such a fan member may be of any particular construction.
As shown by Figure 5, a fan member 68 may be positioned
immediately upstream of the first spaced apart member 12 of prandtl
layer turbine unit 64. It will also be appreciated as also shown in Figure
5 that fan member 68 may be positioned upstream from upstream end
10 78 of prandtl layer combining at 66. Fan member 68 has a plurality of
blades 72 which are configured to direct fluid towards central opening
22 of the first spaced apart member 12. Blades may be mounted on a
hub so as to rotate around shaft 20. Alternately, for example, fan 70
may be a squirrel cage fan or the like. As shown in Figure 5, blades 72
15 are angled such that when fan member 68 rotates, fluid is directed
under pressure at central opening 22.
Fan member 68 may be non-rotationally mounted on
shaft 20 so as to rotate with spaced apart members 12. Alternately, fan
member 68 may be mounted for rotation independent of the rotation
20 of shaft 20, such as by bearings 76 which engage ring 18 (as shown in
dotted outline in Figure 5) or fan member 68 may be driven by a motor
if it is mounted on a different shaft (not shown). If the prandtl layer
turbine is functioning as a pump, then if fan member 68 is non-
rotationally mounted on shaft 20, the rotation of shaft 20 will cause
25 blades 72 to pressurize the fluid as it is introduced into the rotating
spaced apart members. Alternately, if the prandtl layer turbine unit is
to function as a motor, the movement of the fluid through housing 14
may be used to cause spaced apart members 12 to rotate and,
accordingly, fan member 68 to rotate (if fan member 68 is freely
30 rotatably mounted in housing 14). By pressurizing the fluid as it
enters the spaced apart members with no other changes to spaced apart
CA 02258426 1999-O1-08
-17-
members 12, the pressure at outlet 62 is increased. As the downstream
pressure may be increased, then there is additional draw on the fluid
which allows additional spaced apart members 12 to be added to the
prandtl layer turbine unit 64, 66.
Outlet fan members 70 may be mounted in the same
manner as fan member 68. For example, outlet fan 70 may be non-
rotatably mounted on shaft 20, or rotatably mounted in housing 14
independent of spaced apart member 12 such as by a bearing 76 (not
shown). Blade 72 may be configured so as to direct fluid out of
housing 14 through outlet 62. If fan member 70 is outside housing 14,
then fan member is constructed so as to draw fluid from outlet 62 (not
shown). By providing a source of decreased pressure at or adjacent
outlet 62, additional spaced apart members may be provided in a single
prandtl layer turbine unit 64, 66. Further, an increased amount of the
fluid may travel towards downstream end 80 such that the amount of
fluid which passes over each spaced apart member 12 will be more
evenly distributed.
In another preferred embodiment of the instant
invention, the surface area of motive force transfer region 26 of
opposed surfaces 44, 46 varies between at least two immediately
adjacent spaced apart members 12. This may be achieved by varying
one or both of the inner diameter and the outer diameter of spaced
apart members 12.
Preferably, for at least a portion of the spaced apart
members 12 of a prandtl layer turbine unit 64, 66, the distance between
inner edge 40 and outer edge 42 of a spaced apart member 12 varies to
that of a neighbouring spaced apart member 12. More preferably, the
distance between inner edge 40 and outer edge 42 of a spaced apart
member 12 varies to that of a neighbouring spaced apart member 12
for all spaced apart members in a prandtl layer turbine unit 64, 66. The
distance between inner edge 40 and outer edge of 42 of spaced apart
CA 02258426 1999-O1-08
-18-
members 12 may increase in the downstream direction and preferably
increases from upstream end 78 towards downstream end 80.
Alternately, the distance between inner edge 40 and outer edge of 42 of
spaced apart members 12 may decrease in the downstream direction
and preferably decreases from upstream end 78 towards downstream
end 80.
As shown in Figures 5 and 6, the size of central opening 22
of at least one of the discs of prandtl air turbine unit 64, 66 varies from
the size of the central opening of the remaining spaced apart members
10 12 of that prandtl air turbine unit.
Figure 6 is a schematic diagram, in flow order, of the top
plan views of spaced apart members 12 of prandtl layer turbine unit 64.
As shown in this drawing, each spaced apart member has a centrally
positioned shaft opening 74 for non-rotatably receiving shaft 20 (if
15 shaft 20 has a square cross-section similar in size to that of shaft
opening 74). It will be appreciated that spaced apart members 12 may be
fixedly mounted to shaft 20 by any means known in the art.
In a more preferred embodiment, a major proportion of
the spaced apart members have central openings 22 which are of
20 varying sizes and, in a particularly preferred embodiment, the size of
cental opening 22 varies amongst all of the spaced apart members of a
prandtl layer turbine unit 64, 66. An example of this construction is
also shown in Figures 8 and 9.
As the size of central opening 22 increases, then the
25 amount of fluid which may pass downstream through the cental
opening 22 of a spaced apart member 12 increases. Accordingly, more
fluid may be passed downstream to other spaced apart members where
the fluid may be accelerated. The size of central opening 22 may
decrease in size for at least a portion of the spaced apart members 12
30 between upstream end 78 and downstream end 80. As shown in the
embodiment of Figure 8, the size of central opening 22 may
CA 02258426 1999-O1-08
-19-
continually decrease in size from upstream end 78 to downstream end
80.
An advantage of this embodiment is that the amount of
fluid which may pass through housing 14 per unit of time is increased.
This is graphically represented in Figure 7 wherein the relative
amount of fluid which may flow per unit time through a prandtl layer
turbine may be maximized by adjusting the ratio of the inner diameter
of a spaced apart member 12 to its outer diameter. This ratio will vary
from one prandtl layer turbine to another depending upon, inter alia,
10 the speed of rotation of spaced apart members 12 when the turbine is
in use, the spacing between adjacent spaced apart members. However,
as the size of cental opening 22 increases, then, for a given size of a
spaced apart member 12, the surface area of motive force transfer
region 26 of spaced apart member 12 is decreased. Accordingly, this
15 limits the velocity which the fluid may achieve as it travels between
inner edge 40 and outer edge 42 of a spaced apart member 12 on its way
to outlet 62. Thus, by increasing the amount of fluid which may flow
through the prandtl layer turbine 10, the amount of suction which
may be exerted on the fluid at inlet 60 is decreased as is also shown in
20 Figure 7.
The size of central opening 22 may increase in size for at
least a portion of the spaced apart members 12 between upstream end
78 and downstream end 80. As shown in Figure 9, the size of cental
opening 22 may continuously increase from upstream end 78 to
25 downstream end 80. Less fluid passes through each central opening 22
to the next spaced apart member 12 in the downstream direction.
Accordingly, less fluid will be available to be accelerated by each
successive spaced apart member 12 and accordingly each successive
spaced apart member 12 may have a smaller motive force transfer area
30 26 to achieve the same acceleration of the fluid adjacent the opposed
surface 44, 46 of the respective spaced apart member 12.
CA 02258426 1999-O1-08
-20-
In the embodiments of Figures 8 and 9, the size of
openings 22 varies from one spaced apart member to the next so as to
form, in total, a generally trumpet shaped path (either decreasing from
upstream end 78 to downstream end 80 (Figure 8) or increasing from
upstream end 78 to downstream end 80 (Figure 9). It will be
appreciated that the amount of difference between the size of central
openings 22 of any to adjacent spaced apart members 12 may vary by
any desired amount. Further, the size of the openings may alternately
increase and decrease from one end 78, 80 to the other end 78, 80.
As shown in Figure 5, more than one prandtl layer
turbine unit 64, 66 may be provided in a housing 14. Further, the size
of central opening 22 of the spaced apart members 12 of any particular
prandtl layer turbine unit 64, 66 may vary independent of the change
of size of central openings 22 of the spaced apart members 12 of a
different prandtl layer turbine 64, 66 in the same housing 14 (not
shown). As shown in Figure 5, the size of central opening 22 decreases
from each upstream end 78 to each downstream end 80. However, it
will be appreciated that, if desired, for example, the size of central
openings 22 may decrease in size from upstream end 78 to
downstream end 80 of prandtl air turbine unit 64 while the size of
central openings 22 may increase in size from upstream end 78 to
downstream end 80 of prandtl layer turbine unit 66.
Figures 10 and 11 show a further alternate embodiment
wherein the size of cental openings 22 varies from end 78, 80 to the
other end 78,80. In this particular design, the fluid inlet is positioned
centrally between two prandtl layer turbine units 64, 66. In the
embodiment of Figure 10, the size of cental opening 22 increases from
upstream end 78 to downstream end 80 thus producing a prandtl layer
turbine 10 which has improved suction. This is particularly useful if
the prandtl layer turbine is to be used as a pump or fan to move a
fluid.
CA 02258426 1999-O1-08
-21-
In the embodiment of Figure 11, the size of central
opening 22 decreases from upstream end 78 to downstream end 80
thus producing a prandtl layer turbine 10 that has improved fluid
flow. This particular embodiment would be advantageous if the
prandtl layer turbine end were used as a compressor or pump.
In the embodiments of Figure 5 - 9, each spaced apart
member 12 is in the shape of a disc which has the same outer
diameter. Further, the housing has a uniform diameter. Accordingly,
for each spaced apart member 12, space 56 (which extends from outer
10 edge 42 of each spaced apart member 12 to the inner surface of
longitudinally extending 18) has the same radial length. In a further
alternate embodiment of this invention, the outer diameter of each
spaced apart member 12 may vary from one end 78, 80 to the other end
78, 80 (see Figures 12 and 13). In such an embodiment, space 56 may
15 have a differing radial length (see Figure 12) or it may have the same
radial length (see Figure 13). If prandtl layer turbine 10 is to be used as a
separator, the then space 56 preferably includes a portion 56a which is
an area of reduced velocity fluid (eg. a dead air space) in which the
separated material may settle out without being re-entrained in the
20 fluid. For example, as shown in Figure 12b, ring 18 has an elliptical
portion so as to provide portion 56a.
It will be appreciated that in either of these embodiments,
the size of cental opening 22 may remain the same (as is shown in
Figure 13) or, alternately, cental opening 22 may vary in size. For
25 example, as shown in Figure 12, cental opening may increase in size
from upstream end 78 to downstream end 80. This particular
embodiment is advantageous as it increases the negative pressure in
housing 14 at downstream end 80. and increases the fluid flow
through prandtl layer turbine 10. Alternately, the size of cental
30 opening 22 may vary in any other manner, such as by decreasing in
size from upstream end 78 to downstream end 80 (not shown).
CA 02258426 1999-O1-08
-22-
In a further preferred embodiment of the instant
invention, a plurality of prandtl layer turbine units 64, 66 may be
provided wherein the surface area of the motive force transfer region
26 of the spaced apart members 12 of one prandtl layer turbine unit 64,
5 66 have is different to that of the spaced apart members 12 of another
prandtl layer turbine unit 64, 66. This may be achieved by the outer
diameter of at least some of the spaced apart members 12 of a first
prandtl layer turbine unit 64 having an outer diameter which is
smaller than the outer diameter of at least some of the spaced apart
10 members 12 of a second prandtl layer turbine unit 66. In a preferred
embodiment, all of the spaced apart members 12 of prandtl layer
turbine unit 64 have an outer diameter which is smaller than the
outer diameter of each of the spaced apart members 12 of prandtl layer
turbine unit 66. Examples of these embodiments are shown in Figures
15 14 - 17. It will be appreciated that more than two prandtl layer turbine
units 64, 66 may be provided in any particular prandtl layer turbine 10.
Two have been shown in Figures 14 - 17 for simplicity of the drawings.
Referring to Figures 14 and 15, the spaced apart members
12 of prandtl layer turbine unit 64 have the same outer diameter and
20 the spaced apart members 12 of prandtl layer turbine unit 66 have the
same outer diameter. The outer diameter of the spaced apart members
12 of prandtl layer turbine unit 64 is smaller than the outer diameter of
the spaced apart members 12 of prandtl layer turbine unit 66. As
discussed above with respect to Figures 5 - 13, the outer diameter
25 and/or the inner diameter of the spaced apart members of one or both
of prandtl layer turbine units 64, 66 may vary so that the surface area of
motive force transfer area 26 may vary from one spaced apart member
12 to another spaced apart member 12 in one or both of prandtl layer
turbine units 64, 66.
30 As shown in Figure 14, prandtl layer turbine unit 64 is
provided in series with prandtl layer turbine unit 66. Further, the
CA 02258426 1999-O1-08
-23-
spaced apart members 12 of prandtl layer turbine unit 64 are non-
rotatably mounted on shaft 20' and the spaced apart members 12 of
prandtl layer turbine unit 66 are non-rotatably mounted on shaft 20. It
will be appreciated that prandtl layer turbine unit 64 may be provided
in the same housing 14 as prandtl layer turbine unit 66 or, alternately,
it may be provided in a separate housing which is an airflow
communication with the housing of prandtl layer turbine unit 66.
Preferably, in such an embodiment, each prandtl layer turbine unit 64,
66 is mounted co-axially. Optionally, the spaced apart members of
prandtl layer turbine units 64 and 66 may be non rotationally mounted
on the same shaft 20 (see for example Figures 16 and 17).
Prandtl layer turbine unit 64 has inlet 60' and is
rotationally mounted on shaft 20' whereas prandtl layer turbine unit
66 as an inlet 60 and is mounted for rotation on shaft 20. Fluid passes
through spaced apart members 12' to outlet 62' from where it is fed to
inlet 60 such as via passage 61. Thus the fluid introduced into prandtl
layer turbine unit 66 may have an increased pressure. Passage 61 may
extend in a spiral to introduce fluid tangentially to prandtl layer
turbine units 66. Thus the fluid introduced into prandtl layer turbine
unit 66 may already have rotational momentum in the direction of
rotation of spaced apart members 12.
In a further preferred embodiment as shown in Figures 16
and 17, prandtl layer turbine unit 64 may be nested within prandtl
layer turbine unit 66. For ease of reference, in Fi~urP 1~ the ran+al
openings and motive force transfer regions of prandtl layer turbine
unit 64 are denoted by reference numerals 22' and 26'. The central
opening and motive force transfer regions of the spaced apart
members of prandtl layer turbine unit 66 are denoted by reference
numerals 22 and 26. The spaced apart members of prandtl layer turbine
units 64 and 66 may be mounted on the same shaft 20 or the spaced
apart members of each prandtl layer turbine unit 64, 66 may be
CA 02258426 1999-O1-08
-24-
mounted on its own shaft 20 (as shown in Figure 14).
It will be appreciated that prandtl layer turbine unit 64
may be only partially nested within prandtl layer turbine 66. For
example, the upstream spaced apart members 12 of prandtl layer
5 turbine unit 64 may be positioned upstream from the first spaced apart
member 12 of prandtl layer turbine unit 66 (not shown). Further,
prandtl layer turbine units 64, 66 need not have the same length. For
example, as shown in Figure 16, prandtl layer turbine unit 64
comprises four discs whereas prandtl layer turbine unit 66 comprises
10 seven discs. In this embodiment, the prandtl layer turbine unit 64
commences at the same upstream position as prandtl layer turbine
unit 66 but terminates at a position intermediate of prandtl layer
turbine unit 66. It will be appreciated that prandtl layer turbine unit 64
may extend conterminously for the same length as prandtl layer
15 turbine unit 66. Further, it may commence at a position downstream
of the upstream end of prandtl layer turbine unit 66 and continue to
an intermediate position of prandtl layer turbine unit 66 or it may
terminate to or past the downstream end of prandtl layer turbine unit
66.
20 In a further alternate preferred embodiment, as shown in
Figure 14, prandtl layer turbine unit 64 is rotationally mounted on
shaft 20' whereas prandtl layer turbine unit 66 is mounted for rotation
on shaft 20. For example, shaft 20' may be rotationally mounted
around shaft 20 by means of bearings 82 or other means known in the
25 art. In this manner, spaced apart members 12 of prandtl layer turbine
unit 64 may rotate at a different speed to spaced apart members 12 of
prandtl layer turbine unit 66. Preferably, prandtl layer turbine unit 64
(which has spaced apart members 12 having a smaller outer diameter)
rotates at a faster speed than prandtl layer turbine unit 66. For
30 example, if a first prandtl layer turbine unit had discs having a two
inch outer diameter, the prandtl layer turbine unit could rotate at
CA 02258426 1999-O1-08
-25-
speeds up to, eg., about 100,000 rpm. A second prandtl layer turbine
unit having larger sized discs (eg. discs having an outer diameter from
about 3 to 6 inches) could rotate at a slower speed (eg. about 35,000
rpm). Similarly, a third prandtl layer turbine unit which had discs
5 having an even larger outer diameter (eg. from about 8 to about 12
inches) could rotate at an even slower speed (eg. about 20,000 rpm). In
this way, the smaller discs could be used to pressurize the fluid which
is subsequently introduced into a prandtl layer turbine unit having
larger discs. By boosting the pressure of the fluid as it is introduced to
10 the larger, slower rotating discs, the overall efficiency of the prandtl
layer turbine 10 may be substantially increased. In particular, each stage
may be designed to operate at its optimal flow or pressure range.
Further, if the fluid is compressible. For example, the increase in the
inlet pressure will increase the outlet pressure, and therefore the
15 pressure throughout housing 14. This increase in pressure, if
sufficient, will compress the fluid (eg. a gas or a compressible fluid) in
housing 14. This increases the density of the fluid and the efficiency of
the transfer of motive force between the fluid and the spaced apart
members.
20 Referring to Figures 18 and 19, a further preferred
embodiment of the instant invention is shown. Fluid outlet port 62
extends between a first end 84 and a second end 86. Traditionally, in
prandtl layer turbine units, outlet port 62 has extended along a straight
line between first and second ends 84 and 86. According to the
25 preferred embodiment shown in Figures 18 and 19, second and 86 of
fluid outlet port 62 is radially displaced around housing 14 from first
end 84. The portion of the fluid that passes downstream through
opening 22 of a spaced apart member 12 will have some rotational
momentum imparted to in even though it does not pass outwardly at
30 that location adjacent that spaced apart member. Therefore, assuming
that all spaced apart members are similar, the portion of the fluid
CA 02258426 1999-O1-08
-26-
which passes outwardly along the next spaced apart member will
delaminate at a different position due to the rotational momentum
imparted by its passage through opening 22 in the immediate
upstream spaced apart member. Outlet 62 is preferably configure to
5 have an opening in line with the direction of travel of the fluid as it
delaminates and travels to ring 18. Thus downstream portions of
outlet 62 are preferably radially displaced along ring 18 in the direction
of rotation of spaced apart members 12.
Preferably, fluid outlet port 62 is curved and it may extend
as a spiral along ring 18. Preferably, the curvature or spiral extends in
the same direction as the rotation of the spaced apart members 12. The
fluid flow in prandtl layer turbine 10 is generally represented by the
arrow shown in Figure 19. As represented by this arrow, the fluid will
travel in a spiral path outwardly across an opposed surface 44, 46 and
15 then radially outwardly through fluid outlet port 62. Fluid outlet port
62 preferably curves in the same direction as the direction of the
rotation of the spaced apart members.
It will be appreciated that all of fluid outlet port 62 need
not be curved as shown in Figures 18 and 19. For example, a portion of
fluid outlet port 62 may be curved and the remainder may extend in a
straight line as is known in the prior art. It will further be appreciated
that while fluid outlet port 62 in Figure 18 extends conterminously
with spaced apart members 12, first and second ends 84 and 86 need
not coincide with the upstream and downstream ends of the spaced
25 apart members 12. In particular, fluid outlet port 62 may have any
longitudinal length as is known in the art.
According to further preferred embodiment of the instant
invention, a single prandtl layer turbine unit 64, 66 may have a
plurality of outlets 62. Each outlet 62 may be constructed in any
30 manner known in the art or, alternately they may be constructed as
disclosed herein. For example, they may extend in a spiral or curved
CA 02258426 1999-O1-08
-27-
fashion around ring 18 in the direction of rotation of spaced apart
members 12 of a prandtl layer turbine unit 64, 66. Referring to Figure
20, the ring of a prandtl layer turbine 10 having a single prandtl layer
turbine unit 64, 66 is shown. In this embodiment, two outlets, 90 and
5 92 are provided. Each outlet extends longitudinally along ring 18 from
upstream end 78 of spaced apart members 12 to downstream end 80 of
spaced apart members 12. For ease of reference, spaced apart members
12 have not been shown in Figure 20.
Each outlet 90, 92 may be of any particular construction
10 known in the art or taught herein. For example, each outlet 90, 92 may
extend in a curve or spiral around ring 18. Outlets 90, 92 may have the
same degree of curvature or, alternately, the degree of curvature may
vary to allow separation of a specific density and mass of particulate
matter. For example, if prandtl layer turbine 10 is used for particle
15 separation, particles having a different shape and/or mass will travel
outwardly at different positions. The outlets are preferably positioned
to receive such streams and thus their actual configuration will vary
depending upon the particle separation characteristics of the turbine.
Each outlet 90, 92 may curve in the same direction (eg. the
20 direction of rotation of spaced apart members 12). Alternately, they
may curve in opposite directions or one or both may extend in a
straight line as is known in the prior art. Further, a plurality of such
outlets 90 may be provided.
It will be appreciated that in an alternate embodiment,
25 each outlet 90, 92 may be a portion 56a wherein the separated
particulate matter may settle out and be removed from housing 14 and
an outlet 62 may be provided to receive the fluid from which the
particulate material has been removed.
Assuming that the portion of a fluid which is introduced
30 through a central opening 22 to a position adjacent an opposed surface
44, 46 has approximately the same momentum, and assuming that the
CA 02258426 1999-O1-08
-28-
fluid has portions of differing density, then the rotation of spaced apart
member 12 will cause the portions of the fluid having differing
densities to commence rotating around shaft 20 at differing rates. As
the fluid travels outwardly between inner edge 40 and outer edge 42
5 during its travel around shaft 20, the portions of the fluid having
differing densities will tend to delaminate and travel outwardly
towards ring 18 at different locations around ring 18. Accordingly, in a
preferred embodiment of this invention, a fluid outlet port is
positioned to receive each portion of the fluid as it delaminates from
10 the opposed surface. Accordingly, in the embodiment shown in
Figure 20, it is assumed that the fluid would contain two distinctive
portions (eg. two elements having differing densities). Fluid outlet
ports 90 and 92 are angularly displaced around ring 18 so as to each
receive one of these portions.
15 If the fluid also contains a solid, then, due to aerodynamic
effects, particles having the same density but differing sizes will tend to
separate due to the centrifugal forces exerted upon the particles as they
travel in the fluid from inner edge 40 to outer edge 42. Accordingly, a
prandtl layer turbine may also be utilized as a particle separator. For
20 example, in the embodiment of Figure 20, if the particles have the
same density, then first outlet 90 may be positioned to receive particles
having a first particle sized distribution and fluid outlet port 92 may be
positioned to receive particles having a smaller particle size
distribution.
25 The positioning of fluid outlet ports 90, 92 may be selected
based upon several factors including the total mass and density of the
fluid and/or particles to be separated, the amount of centrifugal force
which is imparted to the fluid and any entrained particles by spaced
apart members 12 (eg. the inner diameter of spaced apart members 12,
30 the outer diameter spaced apart members 12, the longitudinal spacing
between adjacent spaced apart members 12, the disc thickness and the
CA 02258426 1999-O1-08
-29-
speed of rotation of spaced apart members 12).
In the embodiment of Figure 20, outlets 90 and 92 may be
in flow communication with any downstream apparatus which may
be desired. Accordingly, each portion of the fluid may be passed
downstream for different processing steps.
Referring to Figure 21, two cyclones 94, 96 may be
provided in flow communication with fluid outlet ports 90, 92. For
example, if the fluid includes particulate matter, fluid outlet port 90
may be positioned to receive particles having a first particle sized
distribution. First cyclone 94 may be provided in fluid flow
communication with first outlet port 90 for separating some or all of
the particles from the fluid. Similarly, fluid outlet port 92 may be
positioned to receive a portion of the fluid containing particles having
a different particle sized distribution and second cyclone 96 may be
provided to remove some or all of these particles from the fluid.
Generally, cyclones are effective to efficiently remove
particles over a limited particle size distribution. By utilizing a prandtl
layer turbine to provide streams having different particle size
distributions, each of cyclones 94, 96 may be configured to efficiently
separate the particles which will be received therein from the fluid. It
will be appreciated that a plurality of such cyclones 94, 96 may be
provided. Each cyclone 94, 96 may be of any particular design known
in the art. Further, they may be the same or different.
It will be appreciated that while several improvements in
prandtl layer turbines have been exemplified separately or together
herein, that they may be used separately or combined in any
permutation or combination. Accordingly, for example, the turbines,
whether nested or in series, may have varying inner and/or outer
diameters. Further, any of the prandtl layer turbines disclosed herein
may have a curved or spiral outlet 62. Further, if a central air inlet 60 is
utilized as disclosed in Figures 10 and 11, two fluid outlet ports having
CA 02258426 1999-O1-08
-30-
the same or differing curvature may be employed or, alternately, all or
a portion of each of the outlets 62 may extend in a straight line. It will
further be appreciated that even if a series of nested turbines are
utilized to pressurize the fluid, that an inlet fan member 68 may also
be incorporated into the design. Further, any of the prandtl layer
turbines disclosed herein may have an outlet fan member 70. These
and other combinations of the embodiments disclosed herein are all
within the scope of this invention.
Prandtl layer turbines may be used in any application
wherein a fluid must be moved. Further, a prandtl layer turbine may
be used to convert pressure in a fluid to power available through the
rotational movement of a shaft.
In one particular application, a prandtl layer turbine may
accordingly be used to assist in separating two or more fluids from a
fluid stream or in separating particulate matter from a fluid stream or
to separate particulate matter carried in a fluid stream into fluid
streams having different particle sized distributions or a combination
thereof (Figures 20 and 21).
A further particular use of such a prandtl layer turbine
20 may be as the sole particle separation device of a vacuum cleaner or,
alternately, it may be used with other filtration mechanisms (eg. filters,
filter bags, electrostatic precipitators and/or cyclones) which may be
used in the vacuum cleaner art.
Referring to Figure 22, a vacuum cleaner including a
prandtl layer turbine is shown. In this embodiment, vacuum cleaner
100 includes a first stage cyclone 102 having an air feed passage 104 for
conveying dirt laden air to tangential inlet 106. First stage cyclone 102
may be of any particular design known in the industry. The air travels
cyclonically downwardly through first stage cyclone 102 and then
30 upwardly to annular space 108 where it exits first stage cyclone 102. It
will be appreciated by those skilled in the art that cyclone 102 may be of
CA 02258426 1999-O1-08
-31-
any particular orientation. Generally, a first stage cyclone may remove
approximately 90% of the particulate matter in the entrained air.
The partially cleaned air exiting first stage cyclone 102 via
annular space 108 may next be passed through a filter 110. Filter 110
5 may be of any design known in the art. For example, it may comprise
a mesh screen or other filter media known in the art. Alternately, or
in addition, filter 110 may be an electrostatic filter (eg. an electrostatic
precipitator). In such an embodiment, the electrostatic filter is
preferably be designed to remove the smallest particulate matter from
10 the entrained air (eg. up to 30 microns). In another embodiment, the
air may be passed instead to one or most second cyclones. In a further
alternate embodiment, the air may be passed before or after the one or
more second cyclones through filter 110.
The filtered air may then passes next into inlet 60 of
15 prandtl layer turbine 10. Depending upon the efficiency of the cyclone
and the filter (if any) and the desired level of dirt removal, the prandtl
layer turbine may be used to provide motive force to move the dirty
air through the vacuum cleaner but not to itself provide any dirt
separation function. The prandtl layer turbine is preferably positioned
20 in series with the cyclone such that the air exiting the cyclone may
travel in a generally straight line from the cyclone to the prandtl layer
turbine. If the vacuum cleaner is an upright vacuum cleaner, then the
prandtl layer turbine is preferably vertically disposed above the air
outlet from the cyclone. If the vacuum cleaner is a canister vacuum
25 cleaner, then the prandtl layer turbine is preferably horizontally
disposed upstream of the air outlet from the cyclone.
Subsequent to its passage trough the prandtl layer turbine,
the air may be passed through filter 110 and/or one or more second
cyclones in any particular orders. Further, in any embodiment, prior to
30 exiting the vacuum cleaner, the air may be passed through a HEPATM
filter.
CA 02258426 1999-O1-08
-32-
In an alternate embodiment, the prandtl layer turbine may
also function as a particle separator. For example, in the embodiment
of Figure 22, the prandtl layer turbine of Figure 21 has been
incorporated. Prandtl layer turbine 10 separates the particulate matter
5 into two streams having different particle size distributions. These
streams separately exit prandtl layer turbine 10 via outlets 90, 92 and
are fed tangentially into cyclones 94, 96. The cleaned air would then
exits cyclones 94, 96 via clean air outlets 112. This air may be further
filtered if desired, used to cool the motor of the vacuum cleaner or
10 exhausted from the vacuum cleaner in any manner known in the art.
It will be appreciated that these embodiments may also be
used to separate solid material from any combination of fluids (i.e.
from a gas stream, from a liquid stream or from a combined liquid and
gas stream). Further, these embodiments may also be used to separate
15 one fluid from another (eg. a gas from a liquid or two liquids having
differing densities).
In a further particular application, two prandtl layer
turbines may be used in conjunction whereby a first prandtl layer
turbine is used as a motor and a second prandtl layer turbine is used as
20 a fan/pump to move a fluid. The prandtl layer turbine which is used
as a motor is drivingly connected to provide motive force to the
second prandtl layer turbine. An example of such an embodiment is
shown in Figure 23. In Figure 23, reference numeral 10' denotes the
prandtl layer turbine which is used as a motor (the power producing
25 prandtl layer turbine). Reference numeral 10 denotes the prandtl layer
turbine which is used as a fan/pump (the fluid flow causing element).
Each prandtl layer turbine 10, 10' may be of any particular
construction known in the art or described herein. Further, each
prandtl layer turbine 10, 10' may be of the same construction (eg.
30 number of discs, size of discs, shape of discs, spacing between discs,
inner diameter of discs, outer diameter of discs and the like) or of
CA 02258426 1999-O1-08
-33-
different constructions. It will be appreciated that the configuration of
each prandtl layer turbine 10, 10' may be optimized for the different
purpose for which it is employed.
A first fluid is introduced through inlet port 60' into
5 prandtl layer turbine 10'. The passage of fluid through prandtl layer
turbine 10' causes spaced apart members 12' to rotate thus causing shaft
20 to rotate. The fluid exits prandtl layer turbine 10' through, for
example, outlet 62' which may be of any particular construction
known in the art or described herein.
10 The fluid introduced into prandtl layer turbine 10' may be
a pressurized fluid which will impart motive force to spaced apart
members 12'. Alternately, or in addition, fluid 10 may be produced by
the fluid expanding as it passes through prandtl layer turbine 10'. For
example, if prandtl layer turbine 10' has a substantial pressure drop,
15 then another source of fluid for prandtl layer turbine 10' may be a
pressurized liquid which expands to a gas as it travels through prandtl
layer turbine 10' or a pressurized gas which expands as it travels
through prandtl layer turbine 10. The fluid may also be the
combustion product of a fuel. The fuel may be combusted upstream of
20 prandtl layer turbine 10' or within prandtl layer turbine 10'. The
combustion of the fluid will produce substantial quantities of gas
which must travel through prandtl layer turbine 10' to exit via outlet
62'. Another source of fluid for prandtl layer turbine 10' may be
harnessing natural fluid flows, such as ocean currents, ocean tides, the
25 wind or the like.
As a result of the passage of a fluid through prandtl layer
turbine 10', motive force is obtained which may then be transmitted to
prandtl layer turbine 10. As shown in Figure 23, spaced apart members
12 of prandtl layer turbine 10 are mounted on the same shaft 20 as
30 spaced apart members 12' of prandtl layer turbine 10'. However, it will
be appreciated that prandtl layer turbine 10', and 10 may be coupled
CA 02258426 1999-O1-08
-34-
together in any manner which would transmit the motive force
produced in prandtl layer turbine 10' to the spaced apart members 12 of
prandtl layer turbine 10. For example, each series of spaced apart
members 12, 12' may be mounted on a separate shaft and the shafts
5 may be coupled together by any mechanical means known in the art
such that prandtl layer turbine 10' is drivingly connected to prandtl
layer turbine 10.
Prandtl layer turbine 10 has an inlet 60 which is in fluid
flow connection with a second fluid. The rotation of shaft 12 will
10 cause spaced apart members 12 to rotate and to draw fluid through
inlet 60 to outlet 62. Accordingly, prandtl layer turbine 10' may be used
as a pump or a fan to cause a fluid to flow from inlet 60 to outlet 62.
Depending upon the power input via shaft 20 to prandtl layer turbine
10, the fluid exiting prandtl layer turbine 10 via outlet 62 may be at a
15 substantial elevated pressure.
Accordingly, prandtl layer turbine 10' functions as a motor
and may be powered by various means such as the combustion of fuel.
Accordingly, prandtl layer turbine 10' produces power which is
harnessed and used in prandtl layer turbine 10 for various purposes.
20 Referring to Figures 24 and 25, a prandtl layer turbine
which may be used to produce motive force from a naturally moving
fluid (such as wind or an ocean current or a tide) is shown. In this
embodiment, prandtl layer turbine 10 (which may be of any particular
construction) is provided with a fluid inlet 124 (for receiving wind or
25 water). The entry of the fluid through inlet port 124 causes spaced
apart members 12 to rotate. In this embodiment, the fluid would
travel radially inwardly along spaced apart members 12 from the outer
edge 42 to inner edge 40. The fluid would then travel downstream
through central opening 22 to fluid outlet 126. The rotation of spaced
30 apart members 12 by the fluid would cause shaft 20 to rotate. Shaft 20
exits from prandtl layer turbine 10 and provides a source of rotational
CA 02258426 1999-O1-08
-35-
motive force which may be used in any desired application (eg.
electrical generation and pumping water).
Prandtl layer turbine is preferably rotatably mounted so as
to align inlet 124 with the direction of fluid flow so that the fluid is
directed into prandtl layer turbine 10. It will also be appreciated that
inlet 124 may be configured (such as having a funnelled shape or the
like) to capture fluid and direct it into spaced apart members 12. In
Figure 24, prandtl layer turbine 10 is positioned vertically on support
member 120. It will be appreciated that prandtl layer 10 may also be
horizontally mounted (or at any other desired angle).
Tail 122 may be provided on ring 18 and positioned so as
to align inlet 124 with the fluid flow. Tail 122 may be constructed in
any manner known in the art such that when the portion of the fluid
which does not enter prandtl layer turbine 10 passes around ring 18,
tail 122 causes opening 124 to align with the direction of the fluid flow
thereby assisting in maintaining opening 124 aligned with the fluid
flow as the direction of fluid flow changes.
