U.S. patent application number 10/016029 was filed with the patent office on 2002-08-29 for crossing spiral compressor/pump.
This patent application is currently assigned to Capstone Turbine Corporation. Invention is credited to Bosley, Robert W..
Application Number | 20020119040 10/016029 |
Document ID | / |
Family ID | 23763132 |
Filed Date | 2002-08-29 |
United States Patent
Application |
20020119040 |
Kind Code |
A1 |
Bosley, Robert W. |
August 29, 2002 |
Crossing spiral compressor/pump
Abstract
A crossing spiral compressor or pump having a cylindrical rotor
rotating within a cylindrical stator bore. Both the outer surface
of the rotor and the bore of the stator include a plurality of
spiral fluid flow channels separated by narrow blades, with the
spiral fluid flow channels of the stator bore spiraling in the
reverse or opposite direction relative to the spiral fluid flow
channels of the rotor. The fluid flow channels on the rotor and in
the bore have open sides that face the annular gap between the
rotor and stator with the channels crossing each other at many
locations to facilitate fluid exchange between rotor channels and
bore channels.
Inventors: |
Bosley, Robert W.;
(Cerritos, CA) |
Correspondence
Address: |
Rachele Wittwer
IRELL & MANELLA LLP
1800 Avenue of the Stars, Suite 900
Los Angeles
CA
90067
US
|
Assignee: |
Capstone Turbine
Corporation
|
Family ID: |
23763132 |
Appl. No.: |
10/016029 |
Filed: |
December 11, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10016029 |
Dec 11, 2001 |
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09444014 |
Nov 19, 1999 |
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6361271 |
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Current U.S.
Class: |
415/72 |
Current CPC
Class: |
F05B 2250/15 20130101;
F05B 2250/25 20130101; F04D 3/02 20130101; F04D 5/002 20130101;
F04D 23/008 20130101 |
Class at
Publication: |
415/72 |
International
Class: |
F04D 001/04 |
Claims
What is claimed is:
1. A rotary machine comprising: a stator housing having a central
bore with a plurality of fluid flow channels spiraling in a first
direction; and a rotor rotatably supported within said central bore
of said stator housing, said rotor with a plurality of fluid flow
channels on its outer surface spiraling in a second direction
opposite to said first direction; said plurality of stator housing
bore fluid flow channels separated by blades which are
significantly narrower than the width of said stator housing bore
fluid flow channels and said plurality of rotor fluid flow channels
separated by blades which are significantly narrower than the width
of said rotor fluid flow channels.
2. The rotary machine of claim 1, and in addition, means to
introduce fluid to said plurality of stator housing bore fluid flow
channels and said plurality of rotor fluid flow channels at one end
thereof and to collect fluid at the other end thereof.
3. The rotary machine of claim 2 wherein in the single direction of
fluid flow the fluid generated thrust load on the rotor bearings is
equal to pi times the square of the rotor radius times the
differential fluid pressure across the rotary machine.
4. The rotary machine of claim 1, and in addition, means to
introduce fluid to said plurality of stator housing bore fluid flow
channels and said plurality of rotor fluid flow channels generally
at the midpoint of said rotor and said stator housing, with
generally one half of the introduced fluid travelling in one axial
direction away from said midpoint and the other half of the
introduced fluid travelling away from said midpoint in the opposite
axial direction, and means disposed at each end of said stator
housing and said rotor to collect fluid from said plurality of
stator housing bore fluid flow channels and said plurality of rotor
fluid flow channels.
5. The rotary machine of claim 4 wherein the bi-directional fluid
flow path results in generating minimal to no fluid generated
thrust load on the rotor bearings.
6. The rotary machine of claim 1, and in addition, means to
introduce fluid to said plurality of stator housing bore fluid flow
channels and said plurality of rotor fluid flow channels generally
at each end of said rotor and said stator housing, and means
generally at the midpoint of said stator housing and said rotor to
collect the introduced fluid from said plurality of stator housing
bore fluid flow channels and said plurality of rotor fluid flow
channels.
7. The rotary machine of claim 6 wherein the bi-directional fluid
flow path results in generating minimal to no fluid generated
thrust load on the rotor bearings.
8. The rotary machine of claim 1, and in addition, means to rotate
said rotor with respect to said stator housing to compress or
pressurize the fluid in said plurality of rotor fluid flow channels
and said plurality of stator housing bore fluid flow channels.
9. The rotary machine of claim 1 wherein said fluid is expanded or
depressurized within said plurality of rotor fluid flow channels
and said plurality of stator housing bore fluid flow channels to
impart rotation to said rotor with respect to said stator
housing.
10. The rotary machine of claim 1 wherein each of said plurality of
spiraling fluid flow channels on said rotor crosses many of said
plurality of spiraling fluid flow channels in the central bore of
said stator housing.
11. The rotary machine of claim 1 wherein each of said plurality of
spiraling fluid flow channels in the central bore of said stator
housing crosses many of said plurality of spiraling fluid flow
channels on said rotor.
12. The rotary machine of claim 1 wherein each of said plurality of
spiraling fluid flow channels on said rotor crosses many of said
plurality of spiraling fluid flow channels in the central bore of
said stator housing, and each of said plurality of spiraling fluid
flow channels in the central bore of said stator housing crosses
many of said plurality of spiraling fluid flow channels on said
rotor.
13. The rotary machine of claim 12 wherein the crossing
intersections of said plurality of rotor fluid flow channels with
said plurality of stator housing bore fluid flow channels combine
to form a plurality of elliptical fluid flow channels normal to the
rotational axis of said rotor.
14. The rotary machine of claim 13 wherein the spiral flow patterns
of the fluid in said plurality of rotor fluid flow channels, the
spiral flow pattern of the fluid in said plurality of stator
housing bore fluid flow channels, and the spiral flow pattern of
the fluid in said plurality of elliptical combined fluid flow
channels where the rotor and the stator housing fluid flow channels
cross, will cause the fluid passing through the rotary machine to
alternately pass through the rotor fluid flow channels and through
the stator housing bore fluid flow channels and then repeat this
sequence several more times before exiting the rotary machine.
15. The rotary machine of claim 12 wherein the rotation of said
rotor within said stator housing bore and the crossing
intersections of said plurality of rotor fluid flow channels in
said stator housing bore induce fluid flow along the axis of said
rotor's rotation within the annulus formed between said rotor and
said stator housing bore.
16. The rotary machine of claim 12 wherein the rotation of said
rotor within said stator housing bore and the crossing
intersections of said plurality of rotor fluid flow channels in the
stator housing bore induce a pressure rise in the fluid as the
fluid moves through the rotary machine.
17. The rotary machine of claim 12 wherein the fluid in said
plurality of rotor fluid flow channels leaves the rotor fluid flow
channels and enters said plurality of stator housing bore fluid
flow channels at the crossing intersections of said plurality of
rotor fluid flow channels and said plurality of stator housing bore
fluid flow channels.
18. The rotary machine of claim 12 wherein the fluid in said
plurality of stator housing bore fluid flow channels leaves the
stator housing bore fluid flow channels and enters said plurality
of rotor fluid flow channels at the crossing intersections of said
plurality of stator housing bore fluid flow channels and said
plurality of rotor fluid flow channels.
19. The rotary machine of claim 12 wherein the fluid in said
plurality of rotor fluid flow channels leaves the rotor fluid flow
channels and enters said plurality of stator housing bore fluid
flow channels at the crossing intersections of said plurality of
rotor fluid flow channels and said plurality of stator housing bore
fluid flow channels, and the fluid in said plurality of stator
housing bore fluid flow channels leaves the stator housing bore
fluid flow channels and enters said plurality of rotor fluid flow
channels at the crossing intersections of said plurality of stator
housing bore fluid flow channels and said plurality of rotor fluid
flow channels.
20. The rotary machine of claim 19 wherein the fluid leaving said
plurality of rotor fluid flow channels and entering said plurality
of stator housing bore fluid flow channels at the crossing
intersections of said plurality of rotor fluid flow channels and
said plurality of stator housing bore fluid flow channels, and the
fluid leaving said plurality of stator housing bore fluid flow
channels and entering said plurality of rotor fluid flow channels
at the crossing intersections of said plurality of stator housing
bore fluid flow channels and said plurality of rotor fluid flow
channels, will have a combined flow pattern whose component normal
to said rotor's rotation axis is essentially a spinning motion that
follows the elliptical shape of the combined fluid flow
channel.
21. The rotary machine of claim 1 wherein each of said plurality of
rotor fluid flow channels has a cross section normal to the spiral
axis of that channel that resembles a half circle with the opening
facing the central bore of said stator housing.
22. The rotary machine of claim 1 wherein each of said plurality of
stator housing bore fluid flow channels has a cross section normal
to the spiral axis of that channel that resembles a half circle
with the opening facing said rotor.
23. The rotary machine of claim 1 wherein each of said plurality of
rotor fluid flow channels has a cross section normal to the spiral
axis of that channel that resembles a half circle with the opening
facing the central bore of said stator housing, and each of said
plurality of stator housing bore fluid flow channels has a cross
section normal to the spiral axis of that channel that resembles a
half circle with the opening facing said rotor.
24. The rotary machine of claim 1, when used as a compressor or gas
turbine, wherein the cross sectional area of said plurality of
rotor fluid flow channels decreases from the low pressure end to
the high pressure end of the rotary machine to compensate for
increasing fluid density.
25. The rotary machine of claim 1, when used as a compressor or gas
turbine, wherein the cross sectional area of said plurality of
stator housing bore fluid flow channels decreases from the low
pressure end to the high pressure end of the rotary machine to
compensate for increasing fluid density.
26. The rotary machine of claim 1 wherein the cross sectional area
of said plurality of rotor fluid flow channels and the cross
sectional area of said plurality of stator housing bore fluid flow
channels each decreases from the low pressure end to the high
pressure end of the rotary machine to compensate for increasing
fluid density.
27. The rotary machine of claim 1 wherein the rotor fluid flow
channel blades separating each rotor fluid flow channel from the
adjacent rotor fluid flow channels do not, by virtue of their
width, form seals that resist fluid flow from one rotor fluid flow
channel to either of the adjacent rotor fluid flow channels.
28. The rotary machine of claim 1 wherein the stator housing bore
fluid flow channel blades separating each stator housing bore fluid
flow channel from the adjacent stator housing bore fluid flow
channels do not, by virtue of their width, form seals that resist
fluid flow from one stator housing bore fluid flow channel to
either of the adjacent stator housing bore fluid flow channels.
29. The rotary machine of claim 1 wherein the rotor fluid flow
channel blades separating each rotor fluid flow channel from the
adjacent rotor fluid flow channels do not, by virtue of their
width, form seals that resist fluid flow from one rotor fluid flow
channel to either of the adjacent rotor fluid flow channels, and
the stator housing bore fluid flow channel blades separating each
stator housing bore fluid flow channel from the adjacent stator
housing bore fluid flow channels do not, by virtue of their width,
form seals that resist fluid flow from one stator housing bore
fluid flow channel to either of the adjacent stator housing bore
fluid flow channels.
30. The rotary machine of claim 1 wherein the rotation of said
rotor within said stator housing bore induces the fluid in said
plurality of stator housing bore fluid flow channels to spin about
the stator housing bore fluid flow channel's spiral axis.
31. The rotary machine of claim 1 wherein the rotation of said
rotor within said stator housing bore induces the fluid in said
plurality of rotor fluid flow channels to spin about the rotor
fluid flow channel's spiral axis.
32. The rotary machine of claim 1 wherein said plurality of rotor
fluid flow channels convert rotor shaft power into fluid kinetic or
velocity energy.
33. The rotary machine of claim 1 wherein the high velocity fluid
leaving said plurality of rotor fluid flow channels and entering
said plurality of stator housing bore fluid flow channels will have
much of its kinetic or velocity energy converted into potential or
pressure energy by the stationary stator housing bore fluid flow
channels acting as vaneless diffusers.
34. The rotary machine of claim 1 wherein the fluid passes many
times alternately through the rotor fluid flow channels and stator
housing bore fluid flow channels as the fluid passes through the
rotary machine.
35. The rotary machine of claim 1 wherein the fluid passing through
the rotary machine will experience an increase in kinetic or
velocity energy each time the fluid passes through said plurality
of rotor fluid flow channels.
36. The rotary machine of claim 1 wherein the fluid passing through
the rotary machine will experience a conversion of kinetic or
velocity energy into potential or pressure energy each time the
fluid passes through the stator housing bore fluid flow
channels.
37. The rotary machine of claim 1 wherein said rotor is rotatably
supported within said stator housing bore by grease packed ball
bearings.
38. The rotary machine of claim 1 wherein, when operating at its
highest flow and lowest pressure rise capability, the spiral flow
patterns of the fluid flowing through the rotary machine will have
a loose pitch with a minimum of flow passes through said plurality
of rotor fluid flow channels
39. The rotary machine of claim 1 wherein, when operating at its
highest flow and lowest pressure rise capability, the fluid flow
passing through said plurality of rotor fluid flow channels
increases its kinetic or velocity energy during substantially the
entire period of passage of the fluid through said plurality of
rotor fluid flow channels.
40. The rotary machine of claim 1 wherein, when operating at its
highest flow and lowest pressure rise capability, the fluid flow
passing through said plurality of stator housing bore fluid flow
channels converts its kinetic or velocity energy into potential or
pressure energy during substantially the entire period of passage
of the fluid through said plurality of stator housing bore fluid
flow channels.
41. The rotary machine of claim 1 wherein, when operating at its
lowest flow and highest pressure rise capability, the spiral flow
patterns of the fluid flowing through the rotary machine will have
a tight pitch with a maximum of fluid flow passes through said
plurality of rotor fluid flow channels.
42. The rotary machine of claim 1 wherein, when operating at its
lowest flow and highest pressure rise capability, the fluid flow
passing through said plurality of rotor fluid flow channels
increases its kinetic or velocity energy only during the later part
of its passage through said plurality of rotor fluid flow
channels.
43. The rotary machine of claim 1 wherein, when operating at its
lowest flow and highest pressure rise capability, said plurality of
rotor fluid flow channels behave as rotating diffusers during the
early part of fluid flow passage through said plurality of rotor
fluid flow channels.
44. The rotary machine of claim 1 wherein, when operating at its
lowest flow and highest pressure rise capability, the fluid flow
passing through said plurality of stator housing bore fluid flow
channels will experience conversion of its kinetic or velocity
energy into potential or pressure energy only during the earliest
part of its passage through said plurality of stator housing bore
channels.
45. The rotary machine of claim 1 wherein, when operating at its
lowest flow and highest pressure rise capability, said plurality of
stator housing bore fluid flow channels behave as nozzles,
converting the fluid's potential or pressure energy into kinetic or
velocity energy and producing a local flow with an axial component
opposed to the general fluid flow through the rotary machine.
46. The rotary machine of claim 1 wherein the blades at the radial
flow entry point of said plurality of rotor fluid flow channels
have a radial slope.
47. The rotary machine of claim 1 wherein the blades at the radial
flow entry point of said plurality of rotor fluid flow channels
have a forward leaning slope.
48. The rotary machine of claim 1 wherein the blades at the radial
flow entry point of said plurality of stator housing bore fluid
flow channels have a forward leaning slope.
49. The rotary machine of claim 1 wherein the blades at the radial
flow entry point of said plurality of stator housing bore fluid
flow channels have a radial slope.
50. The rotary machine of claim 1 wherein the blades at the radial
flow entry point of said plurality of rotor fluid flow channels
have a radial slope and the blades at the radial flow entry point
of said plurality of stator housing bore fluid flow channels have a
radial slope.
51. The rotary machine of claim 1 wherein the blades at the radial
flow entry point of said plurality of rotor fluid flow channels
have a forward leaning slope and the blades at the radial flow
entry point of said plurality of stator housing bore fluid flow
channels have a forward leaning slope.
52. The rotary machine of claim 1 wherein the pitch of said
plurality of rotor fluid flow channels spiral varies from one end
of the rotor to the other end.
53. The rotary machine of claim 52 wherein the pitch of said
plurality of rotor fluid flow channels spiral varies from one end
of the rotor to the other end with a tighter pitch and a reduced
channel cross-sectional area at the high pressure end.
54. The rotary machine of claim 1 wherein the cross-sectional area
of said plurality of rotor fluid flow channels is reduced as the
fluid flow approaches the fluid exit.
55. The rotary machine of claim 1 wherein the cross-sectional area
of said plurality of stator housing bore fluid flow channels is
reduced as the fluid flow approaches the fluid exit.
56. The rotary machine of claim 1 wherein the cross-sectional area
of said plurality of rotor fluid flow channels is reduced as the
fluid flow approaches the fluid exit and the cross-sectional area
of said plurality of stator housing bore fluid flow channels is
reduced as the fluid flow approaches the fluid exit.
57. The rotary machine of claim 1 wherein the pitch of said
plurality of stator housing bore fluid flow channels spiral varies
from one end of the rotor to the other end.
58. The rotary machine of claim 57 wherein the pitch of said
plurality of stator housing bore fluid flow channels spiral varies
from one end of the stator housing to the other end with a tighter
pitch and a reduced channel cross-sectional area at the high
pressure end.
59. A rotary machine including a crossing spiral
compressor/pump/turbine and a permanent magnet motor/generator
comprising: a housing including a motor/generator stator positioned
at one end of said housing and a compressor/turbine stator at the
other end of said housing; a shaft rotatably supported within said
housing; a permanent magnet rotor disposed on said shaft at one end
thereof and rotatably supported within said motor/generator stator;
a compressor/pump/turbine disposed at the other end of said shaft
and rotatably supported within said compressor/turbine stator; said
compressor/pump/turbine rotor having a plurality of fluid flow
channels spiraling in a first direction and said compressor/turbine
stator having a plurality of fluid flow channels operably
associated with said plurality of spiraling rotor fluid flow
channels and spiraling in a second direction opposite to said first
direction.
60. The rotary machine of claim 59 wherein said shaft is rotatably
supported within said housing at one end by a single bearing and at
the other end by a duplex bearing.
61. The rotary machine of claim 59 wherein said shaft is rotatably
supported within said housing at one end by a duplex bearing and at
the other end by a single bearing.
62. The rotary machine of claim 59 and in addition, a
bi-directional inverter to provide power to said motor or extract
power from said generator.
63. The rotary machine of claim 62 wherein electrical power is
utilized to produce fluid power when the fluid supplied to the
inlet of the crossing spiral compressor/turbine is at a lower
pressure than that needed at the outlet of the crossing spiral
compressor/turbine.
64. The rotary machine of claim 62 wherein electrical power is
generated when the fluid supplied to the inlet of the crossing
spiral compressor/pump/turbine is at a greater pressure than that
needed at the outlet of the crossing spiral
compressor/pump/turbine.
65. The rotary machine of claim 62 wherein the rotary machine
transitions smoothly from generating electrical power while
expanding or depressurizing the fluid to utilizing electrical power
to compress or pressurize the fluid in response to changes in the
supplied inlet fluid pressure and/or the required outlet fluid
pressure.
66. A method of compressing fluid comprising the steps of:
providing a stator housing having a central bore with a plurality
of fluid flow channels spiraling in a first direction, said
plurality of stator housing bore fluid flow channels separated by
blades which are significantly narrower than the width of said
stator housing bore fluid flow channels; rotatably supporting a
rotor within said central bore of said stator housing, said rotor
with a plurality of fluid flow channels spiraling in a second
direction opposite to said first direction, said plurality of rotor
fluid flow channels separated by blades which are significantly
narrower than the width of said rotor fluid flow channels; and
rotating said rotor within said stator housing bore with the fluid
flow in said plurality of stator housing bore fluid flow channels
crossing the fluid flow in said plurality of rotor fluid flow
channels.
Description
TECHNICAL FIELD
[0001] This invention relates to the general field of compressors
and pumps and more particularly to a compressor/pump having a
crossing spiral fluid flow path.
BACKGROUND OF THE INVENTION
[0002] A crossing spiral compressor/pump is a high-speed rotary
machine that accomplishes compression or pressurization of fluid by
imparting a velocity head to each fluid particle as it passes
through the machine's rotor flow channels and then converting that
velocity head into a pressure head in the bore flow channels of a
stator housing that function as vaneless diffusers. While in this
respect a crossing spiral compressor/pump has some characteristics
in common with a centrifugal compressor or centrifugal pump, the
primary flow in a crossing spiral compressor/pump is axial with a
double helical spin, while in a centrifugal compressor the primary
flow is radial with no spin. The fluid particles passing through a
crossing spiral compressor/pump travel in a tight pitch helical
flow pattern within loosely pitched spiral flow channels on the
outside of the rotor and inside the stator housing bore. The rotor
flow channels are essentially half circles with their open surface
facing outward adjacent to the bore flow channels. The bore flow
channels are essentially half circles with their open surfaces
facing inward adjacent to the rotor flow channels. The adjacent
rotor and bore flow half circle flow channels function together as
a combined channel that is essentially circular. Within the
combined channels, the fluid particles travel along helical
streamlines, the centerline of the helix coinciding with the center
of the combined rotor and bore spiral channels. This flow pattern
causes each fluid particle to pass through the rotor channels many
times while the fluid particles are traveling through the crossing
spiral compressor/pump, each time acquiring kinetic energy. After
each pass through the rotor flow channels, the fluid particles
reenter the adjacent stator housing bore channels where they
convert their kinetic or velocity energy into potential or pressure
energy. This produces an axial pressure gradient in the rotor and
stator housing bore flow channels.
[0003] The multiple passes through the rotor flow channels
(regenerative flow pattern) allows a crossing spiral
compressor/pump to produce discharge heads of up to fifteen (15)
times those produced by a centrifugal compressor operating at equal
tip speeds. Since the cross-sectional area of the flow channels in
a crossing spiral compressor/pump is usually smaller than the
cross-sectional area of the radial flow in a centrifugal
compressor, a crossing spiral compressor/pump would normally
operate at flows which are lower than the flows of a centrifugal
compressor having an equal impeller diameter and operating at an
equal tip speed. These high-head, low-flow performance
characteristics of a crossing spiral compressor/pump make it well
suited to a number of applications where a reciprocating
compressor, a rotary displacement compressor, or a low
specific-speed centrifugal compressor would not be as well
suited.
[0004] A crossing spiral compressor/pump can be utilized as a
turbine by supplying it with a high pressure working fluid,
dropping fluid pressure through the machine, and extracting the
resulting shaft horsepower with a generator. Hence the terms
"compressor/turbine" or "pump/turbine" are used throughout this
application. During normal operation, the crossing spiral machine
can be converted from a compressor/pump into a turbine by reducing
and reversing the discharge head pressure.
[0005] Among the advantages of a crossing spiral compressor/pump or
a crossing spiral turbine are:
[0006] (a) simple, reliable design with only one rotating
assembly;
[0007] (b) stable, surge-free operation over a wide range of
operating conditions (i.e. from full flow with low discharge head
pressure to no flow with high discharge head pressure)
[0008] (c) long operating life (e.g., 40,000 hours) limited mainly
by their bearings;
[0009] (d) freedom from wear product and oil contamination since
there are no rubbing or lubricated surfaces utilized;
[0010] (e) only one stage required compared to multi-stage
centrifugal compressor/pump assemblies of equal pressure rise and
speed; and
[0011] (f) higher operating efficiencies when compared to a very
low specific-speed (high head pressure, low flow, and low impeller
speed) centrifugal compressor.
[0012] On the other hand, a crossing spiral compressor/pump or
turbine cannot compete with a moderate to high specific-speed
centrifugal compressor, in view of their relative efficiencies.
While the best efficiency of a centrifugal compressor at a high
specific-speed (low head and high flow) operating condition would
be on the order of seventy-eight percent (78%), at a low
specific-speed operating condition a centrifugal compressor could
have an efficiency of less than twenty percent (20%). A crossing
spiral compressor/pump operating at the same low specific-speed and
at its best flow can have efficiencies of about fifty-five percent
(55%).
[0013] The flow in a crossing spiral compressor/pump can be
visualized as two fluid streams that first merge and then divide as
they pass through the compressor/pump.
[0014] While the unique capabilities of a crossing spiral
compressor/pump would seem to offer many applications, the low flow
limitation severely curtail their widespread utilization.
[0015] Permanent magnet motors and generators, on the other hand,
are used widely in many varied applications. This type of
motor/generator has a stationary field coil and a rotatable
armature of permanent magnet(s). In recent years, high energy
product permanent magnets having significant energy increases have
become available. Samarium cobalt permanent magnets having an
energy product of twenty-seven (27) megagauss-oersted (mgo) are now
readily available and neodymium-iron-boron magnets with an energy
product of thirty-five (35) megagauss-oersted are also available.
Even further increases of mgo to over 45 megagauss-oersted promise
to be available soon. The use of such high energy product permanent
magnets permits smaller machines capable of supplying higher power
outputs.
[0016] The permanent magnet rotor may comprise a plurality of
equally spaced magnetic poles of alternating polarity or may even
be a sintered one-piece magnet with radial orientation. The stator
would normally include a plurality of windings and magnet poles of
alternating polarity. In a generator mode, rotation of the rotor
causes the permanent magnets to pass by the stator poles and coils
and thereby induces an electric current to flow in each of the
coils. In the motor mode, electrical current is passed through the
coils, which will cause the permanent magnet rotor to rotate.
SUMMARY OF THE INVENTION
[0017] A crossing spiral flow path compressor is a rotary machine
having a rotor disposed to rotate within a stator housing bore,
with the rotor having a plurality of channels spiraling in one
direction and the stator housing bore having a plurality of
channels spiraling in the reverse or opposite direction. The rotor
and stator housing bore channels would be separated by narrow
blades (significantly narrower than the width of the channels) with
minimal blocking of backflow around the blades.
[0018] The crossing spiral compressor/pump may be integrated with a
permanent magnet motor/generator to achieve fluid dynamic
characteristics that are otherwise not readily obtainable. The
crossing spiral compressor/pump and permanent magnet
motor/generator are disposed in a housing with the crossing spiral
compressor/pump at one end and typically the permanent magnet
motor/generator at the other end. The crossing spiral
compressor/pump rotor and the permanent magnet rotor form a common
rotor which is rotatable mounted within this housing typically by
bearings at the ends of the common rotor. Alternately, the common
rotor may be supported by bearings at the ends of the crossing
spiral compressor/pump section of the rotor with the
motor/generator section of the rotor overhanging the bearing
located between the compressor/pump and the motor/generator.
[0019] In one embodiment the flow is introduced at one end and
passes through the entire axial length of the rotor and stator
housing bore channels while in another embodiment the flow is
introduced at the midpoint of the rotor and stator housing bore
channels and travels in both directions away from the midpoint.
Alternately, flow can be introduced at both ends of the rotor and
bore channels.
[0020] It is therefore, a principal aspect of the present invention
to provide an improved compressor or pump that utilizes spiral flow
channels to induce fluid flow and pressure rise within the
fluid.
[0021] It is another aspect of the present invention to provide a
compressor or pump that has a nominally cylindrical rotor.
[0022] It is another aspect of the present invention to provide a
compressor or pump that has a nominally cylindrical bore in the
interior of a non-rotating stator housing within which the rotor
rotates.
[0023] It is another aspect of the present invention to provide a
compressor or pump that has spiral fluid flow channels on the outer
surface of the cylindrical rotor.
[0024] It is another aspect of the present invention to provide a
compressor or pump that has spiral fluid flow channels on the inner
surface of the cylindrical bore.
[0025] It is another aspect of the present invention to provide a
compressor or pump that has spiral fluid flow channels on the inner
surface of the cylindrical bore that spiral in the reverse or
opposite direction relative to the spiral fluid flow channels on
the outer surface of the cylindrical rotor.
[0026] It is another aspect of the present invention to provide a
compressor or pump wherein each spiral fluid flow channel on the
outer surface of the cylindrical rotor crosses many of the spiral
fluid flow channels on the inner surface of the cylindrical
bore.
[0027] It is another aspect of the present invention to provide a
compressor or pump wherein each spiral fluid flow channel on the
inner surface of the cylindrical bore crosses many of the spiral
fluid flow channels on the outer surface of the cylindrical
rotor.
[0028] It is another aspect of the present invention to provide a
crossing spiral compressor or pump wherein each spiral fluid flow
channel on the outer surface of the cylindrical rotor has a cross
section normal to the spiral axis of that channel that resembles a
half circle with the opening facing the inner surface of the
bore.
[0029] It is another aspect of the present invention to provide a
crossing spiral compressor or pump wherein each spiral fluid flow
channel on the inner surface of the cylindrical bore has a cross
section normal to the spiral axis of that channel that resembles a
half circle with the opening facing the outer surface of the
rotor.
[0030] It is another aspect of the present invention to provide a
crossing spiral compressor or pump wherein the crossing
intersections of the spiral fluid flow channels on the outer
surface of the cylindrical rotor with the spiral fluid flow
channels on the inner surface of the cylindrical bore form an
elliptical combined fluid flow channel normal to the rotational
axis of the rotor.
[0031] It is another aspect of the present invention to provide a
crossing spiral compressor or pump wherein the rotation of the
rotor within the stator housing bore and the crossing intersections
of the spiral fluid flow channels on the rotor and in the bore
induce fluid flow along the axis of the rotor's rotation within the
channeled annulus formed between the rotor and bore.
[0032] It is another aspect of the present invention to provide a
crossing spiral compressor or pump wherein the rotation of the
rotor within the stator housing bore and the crossing intersections
of the spiral fluid flow channels on the rotor and in the bore
induce a pressure rise in the fluid as the fluid moves through the
crossing spiral compressor/pump.
[0033] It is another aspect of the present invention to provide a
crossing spiral compressor wherein the cross sectional area of the
fluid flow channels (either or both the rotor or bore) decrease
from the inlet (low pressure) end to the outlet (high pressure) end
of the crossing spiral compressor to compensate for increasing
fluid density.
[0034] It is another aspect of the present invention to provide a
crossing spiral compressor or pump wherein the fluid dynamic blades
separating each fluid flow channel from the adjacent fluid flow
channels are narrow in comparison to the width of the fluid flow
channels on either side (for both the fluid flow channels on the
outer surface of the rotor and the fluid flow channels on the inner
surface of the stator housing bore).
[0035] It is another aspect of the present invention to provide a
crossing spiral compressor or pump wherein the fluid dynamic blades
separating each fluid flow channel from the adjacent fluid flow
channels do not, by virtue of their width, form seals that resist
fluid flow from one channel on the rotor to either of the adjacent
channels on the rotor or from one channel in the stator housing
bore to adjacent channels in the stator housing bore.
[0036] It is another aspect of the present invention to provide a
crossing spiral compressor or pump wherein the fluid in the rotor
flow channels leaves those channels and enters the stator housing
bore flow channels at the crossing intersections of the rotor and
the bore fluid flow channels.
[0037] It is another aspect of the present invention to provide a
crossing spiral compressor or pump wherein the fluid in the stator
housing bore flow channels leaves those channels and enters the
rotor flow channels at the crossing intersections of the bore and
the rotor fluid flow channels.
[0038] It is another aspect of the present invention to provide a
crossing spiral compressor or pump wherein the fluid leaving the
rotor flow channels and entering the stator housing bore flow
channels at the crossing intersections of the rotor and the bore
fluid flow channels and the fluid leaving the stator housing bore
flow channels and entering the rotor flow channels at the crossing
intersections of the rotor and the bore fluid flow channels will
have a combined flow pattern whose component normal to the rotor's
rotation axis is essentially a spinning motion that follows the
elliptical shape of the combined fluid flow channel.
[0039] It is another aspect of the present invention to provide a
crossing spiral compressor or pump wherein the rotation of the
rotor within the stator housing bore induces the fluid in the
stator housing bore fluid flow channels to spin about the bore
fluid flow channel's spiral axis.
[0040] It is another aspect of the present invention to provide a
crossing spiral compressor or pump wherein the rotation of the
rotor within the stator housing bore induces the fluid in the rotor
fluid flow channels to spin about the rotor fluid flow channel's
spiral axis.
[0041] It is another aspect of the present invention to provide a
crossing spiral compressor or pump wherein the rotor fluid flow
channels convert rotor shaft power into fluid kinetic or velocity
energy as would a centrifugal compressor or pump impeller.
[0042] It is another aspect of the present invention to provide a
crossing spiral compressor or pump wherein the high velocity fluid
that has just left the rotor fluid flow channels and has just
entered the stator housing bore fluid flow channels will have much
of its kinetic or velocity energy converted into potential or
pressure energy by the stationary stator housing bore fluid flow
channels that function in a manner similar to a vaneless diffuser
in a centrifugal compressor or pump.
[0043] It is another aspect of the present invention to provide a
crossing spiral compressor or pump wherein the spiral flow patterns
of the fluid in the rotor fluid flow channels, the spiral flow
pattern of the fluid in the stator housing bore fluid flow
channels, and the spiral flow pattern of the fluid in the
elliptical combined fluid flow area where the rotor and the stator
housing fluid flow channels cross, will cause the fluid passing
through the compressor or pump to alternately pass through the
rotor fluid flow channels and through the stator housing bore fluid
flow channels and then repeat this sequence several more times
before exiting the compressor or pump.
[0044] It is another aspect of the present invention to provide a
crossing spiral compressor or pump wherein the spiral flow patterns
of the fluid in the compressor or pump can be characterized as
vortex flow patterns, regenerative flow patterns, or multi-pass
flow patterns since the fluid passes many times through the rotor
and bore fluid flow channels (alternately through each type of
channel) as the fluid passes through the compressor or pump.
[0045] It is another aspect of the present invention to provide a
crossing spiral compressor or pump wherein the fluid passing
through the compressor or pump will experience a conversion of
kinetic or velocity energy into potential or pressure energy every
time the fluid passes through the stator housing bore flow
channels.
[0046] It is another aspect of the present invention to provide a
crossing spiral compressor or pump wherein the pressure rise in the
fluid passing through the compressor or pump can be many times the
pressure rise of fluid passing through a single pass centrifugal
compressor or pump of equal tip speed (impeller circumference times
impeller revolutions per second) owing to the multi-pass nature of
the present invention.
[0047] It is another aspect of the present invention to provide a
crossing spiral compressor or pump wherein the rotor tip speed and
usually the rotor rpm can be much lower than for a single pass
centrifugal compressor or pump of equal pressure rise and flow
rate, owing to the multi-pass nature of the present invention.
[0048] It is another aspect of the present invention to provide a
crossing spiral compressor or pump which operates at such a low
speed that the rotor bearing requirements may be satisfied by
utilizing grease packed ball bearings.
[0049] It is another aspect of the present invention to provide a
crossing spiral compressor or pump wherein, when operating at its
highest flow and lowest pressure rise capability, the spiral flow
patterns of the fluid flowing through the compressor or pump will
have a loose pitch with a minimum of flow passes through the
rotor.
[0050] It is another aspect of the present invention to provide a
crossing spiral compressor or pump wherein, when operating at its
highest flow and lowest pressure rise capability, the fluid flow
passing through the rotor flow channels will experience increases
in its kinetic or velocity energy during its entire period of
passage through these channels.
[0051] It is another aspect of the present invention to provide a
crossing spiral compressor or pump wherein, when operating at its
highest flow and lowest pressure rise capability, the fluid flow
passing through the stator housing bore flow channels will
experience conversion of its kinetic or velocity energy into
potential or pressure energy during its entire period of passage
through these channels.
[0052] It is another aspect of the present invention to provide a
crossing spiral compressor or pump wherein, when operating at its
lowest flow and highest pressure rise capability, the spiral flow
patterns of the fluid flowing through the compressor or pump will
have a tight pitch with a maximum of flow passes through the
rotor.
[0053] It is another aspect of the present invention to provide a
crossing spiral compressor or pump wherein, when operating at its
lowest flow and highest pressure rise capability, the fluid flow
passing through the rotor flow channels will experience increases
in its kinetic or velocity energy only during the latter part of
its passage through these channels. During the earlier part of its
passage through these channels, these channels behave as rotating
diffusers, converting the kinetic or velocity energy (associated
with the backwards flow exiting the stator housing bore fluid flow
channels and entering the rotor fluid flow channels) into potential
or pressure energy.
[0054] It is another aspect of the present invention to provide a
crossing spiral compressor or pump wherein, when operating at its
lowest flow and highest pressure rise capability, the fluid flow
passing through the stator housing bore flow channels will
experience conversion of its kinetic or velocity energy into
potential or pressure energy only during the earliest part of its
passage through these channels. During the latter part of its
passage through these channels, these channels behave as nozzles,
converting the fluid's potential or pressure energy into kinetic or
velocity energy and producing a local flow with an axial component
opposed to the general fluid flow through the compressor or
pump.
[0055] It is another aspect of the present invention to provide a
crossing spiral compressor or pump wherein the blades at the radial
flow entry point of the rotor fluid flow channels can have either a
radial slope or a forward leaning slope. The forward leaning slope
can reduce fluid shock losses and will result in a rotor fluid flow
channel cross section that deviates moderately from that of a half
circle. The radial slope can have manufacturing advantages and will
result in a rotor fluid flow channel cross section that
approximates that of a half circle.
[0056] It is another aspect of the present invention to provide a
crossing spiral compressor or pump wherein the blades at the radial
flow entry point of the stator housing bore fluid flow channels can
have either a radial slope or a forward leaning slope. The forward
leaning slope can reduce fluid shock losses and will result in a
stator housing bore fluid flow channel cross section that deviates
moderately from that of a half circle. The radial slope can have
manufacturing advantages and will result in a stator housing bore
fluid flow channel cross section that approximates that of a half
circle.
[0057] It is another aspect of the present invention to provide a
crossing spiral compressor wherein the pitch of the rotor fluid
flow channel spiral can vary from one end of the rotor to the other
end, typically having a tighter pitch and a reduced channel
cross-sectional area at the high pressure end.
[0058] It is another aspect of the present invention to provide a
crossing spiral compressor wherein the cross-sectional area of the
rotor fluid flow channel is reduced as the fluid flow approaches
the fluid exit.
[0059] It is another aspect of the present invention to provide a
crossing spiral compressor wherein the cross-sectional area of the
stator fluid flow channel is reduced as the fluid flow approaches
the fluid exit.
[0060] It is another aspect of the present invention to provide a
crossing spiral compressor wherein the pitch of the stator housing
bore fluid flow channel spiral can vary from one end of the rotor
to the other end, typically having a tighter pitch and a reduced
channel cross-sectional area at the high pressure end.
[0061] It is another aspect of the present invention to provide a
crossing spiral compressor or pump wherein, in the first
embodiment, the fluid flow enters one end of the rotor and stator
housing bore fluid flow channels and exits the other end of the
fluid flow channels.
[0062] It is another aspect of the present invention to provide a
crossing spiral compressor or pump wherein, in the first
embodiment, the single direction of fluid flow results in a fluid
generated thrust load on the rotor bearings equal to pi times the
square of the rotor radius times the differential fluid pressure
across the compressor or pump.
[0063] It is another aspect of the present invention to provide a
crossing spiral compressor or pump wherein, in the first
embodiment, it is desirable to minimize the diameter of the rotor
to minimize the axial load that the thrust bearings must
support.
[0064] It is another aspect of the present invention to provide a
crossing spiral compressor or pump wherein, in the second
embodiment, the fluid flow enters at the mid point of the crossing
spiral compressor/pump rotor and stator housing bore fluid flow
channels and exits at both ends of the fluid flow channels (or
alternately, enters at both ends and exits at the mid point of the
crossing spiral compressor/pump rotor and stator housing bore).
[0065] It is another aspect of the present invention to provide a
crossing spiral compressor or pump wherein, in the second
embodiment, the bi-directional fluid flow path results in
generating minimal to no fluid generated thrust load on the rotor
bearings.
[0066] It is another aspect of the present invention to provide a
crossing spiral compressor or pump wherein, in the second
embodiment, it is desirable to utilize a larger diameter for the
rotor than with the first embodiment since thrust load is not a
problem and it allows the length of the rotor for bi-directional
flow to be reduced.
[0067] It is another aspect of the present invention to provide a
crossing spiral rotary machine that can function as a compressor or
pump or can function as a turbine for either compressible or
incompressible fluids.
[0068] It is another aspect of the present invention to provide a
crossing spiral compressor or pump wherein the compressor or pump
is driven by an integrated permanent magnet motor/generator.
[0069] It is another aspect of the present invention to provide a
crossing spiral compressor or pump wherein the compressor or pump
is driven by a permanent magnet motor/generator having a
motor/generator stator that is integrally mounted within the
compressor or pump housing and a motor/generator rotor that is
mounted on a common shaft with the compressor or pump rotor and the
integrated compressor/motor/generator or pump/motor/generator share
common bearings.
[0070] It is another aspect of the present invention to provide a
crossing spiral compressor or pump integrated with a permanent
magnet motor/generator wherein the motor/generator is driven by a
bi-directional inverter which can provide power to the motor or
extract power from the generator.
[0071] It is another aspect of the present invention to provide a
crossing spiral compressor or pump integrated with a permanent
magnet motor/generator and utilized with a bi-directional inverter
wherein gaseous fluids are compressed or expanded.
[0072] It is another aspect of the present invention to provide a
crossing spiral compressor or pump integrated with a permanent
magnet motor/generator and utilized with a bi-directional inverter
wherein liquid fluids are pressurized or depressurized.
[0073] It is another aspect of the present invention to provide a
crossing spiral compressor or pump integrated with a permanent
magnet motor/generator and utilized with a bi-directional inverter
wherein electrical power is utilized to produce fluid power when
the fuel (either gaseous or liquid) supplied to the inlet of the
compressor or pump is at a lower pressure than that needed at the
outlet of the compressor or pump.
[0074] It is another aspect of the present invention to provide a
crossing spiral compressor or pump functioning as a turbine and
integrated with a permanent magnet motor/generator and utilized
with a bi-directional inverter wherein electrical power can be
generated when the fuel (either gaseous or liquid) supplied to the
inlet of the compressor or pump is at a greater pressure than that
needed at the outlet of the compressor or pump.
[0075] It is another aspect of the present invention to provide a
crossing spiral compressor or pump integrated with a permanent
magnet motor/generator and utilized with a bi-directional inverter
that can shift or transition smoothly from generating electrical
power while expanding or depressurizing the working fluid to
utilizing electrical power to compress or pressurize the working
fluid in response to changes in the supplied inlet fluid pressure
and/or the required outlet fluid pressure.
[0076] It is another aspect of the present invention to provide a
crossing spiral compressor or pump integrated with a permanent
magnet motor/generator and utilized with a bi-directional inverter
that can precisely control the shaft speed of the compressor or
pump.
[0077] It is another aspect of the present invention to provide a
crossing spiral compressor or pump integrated with a permanent
magnet motor/generator and utilized with a bi-directional inverter
that can precisely control the shaft torque delivered to or
extracted from the compressor/pump by the motor/generator.
[0078] It is another aspect of the present invention to provide a
crossing spiral compressor or pump integrated with a permanent
magnet motor/generator and utilized with a bi-directional inverter
that can precisely control the pressure change that occurs as the
fluid passes through the compressor or pump.
[0079] It is another aspect of the present invention to provide a
crossing spiral compressor or pump integrated with a permanent
magnet motor/generator and utilized with a bi-directional inverter
that can precisely control the fluid energy change that occurs as
the fluid passes through the compressor or pump (e.g. by
controlling the product of shaft speed and shaft torque).
[0080] It is another aspect of the present invention to provide a
crossing spiral compressor or pump integrated with a permanent
magnet motor/generator and utilized with a bi-directional inverter
that can provide volumetric fluid flow rate data for the fluid
passing through the compressor or pump (e.g. by monitoring the
shaft speed and shaft torque).
[0081] It is another aspect of the present invention to provide a
crossing spiral compressor/turbine or pump/turbine that does not
experience fluid dynamic stall or surge instabilities such as are
experienced by centrifugal compressors/pumps/turbines when process
fluid flows are low and the pressure changes experienced by the
process fluid when passing through these devices are large.
[0082] It is another aspect of the present invention to provide a
crossing spiral compressor/turbine or pump/turbine that does not
produce pressure pulsations or flow pulsations such as those
produced by reciprocating compressors.
[0083] It is another aspect of the present invention to provide a
crossing spiral compressor/turbine or pump/turbine that does not
need to be turned on and off in order to control fluid pressure
discharge pressure such as can be the case with reciprocating
compressors driven by constant speed motors when fluid delivery
flow rates must vary.
[0084] It is another aspect of the present invention to provide a
crossing spiral compressor/turbine or pump/turbine that does not
need an accumulator in order to limit fluid discharge pressure
pulsations (e.g. caused by compressor or pump piston strokes) and
to limit fluid discharge pressure variations (e.g. caused by
variations in the required process fluid delivery flow and by
turning the compressor/pump/turbine on and off).
[0085] It is another aspect of the present invention to provide a
crossing spiral compressor/turbine or pump/turbine that has no
rubbing rings, seals or other hardware that can wear.
[0086] It is another aspect of the present invention to provide a
crossing spiral compressor/turbine or pump/turbine that does not
utilize oil lubrication other than grease in ball bearings and does
not discharge oil vapors with the process fluid.
[0087] It is another aspect of the present invention to provide a
crossing spiral compressor/turbine or pump/turbine that produces a
large pressure change in the process fluid with low rotor tip
speeds.
[0088] It is another aspect of the present invention to provide a
crossing spiral compressor/turbine or pump/turbine that operates at
reasonably high efficiencies when machine specific speed is low
(i.e. when pressure change is high, flow is low and tip speed is
low) which is a condition where centrifugal compressors perform
poorly.
[0089] It is another aspect of the present invention to provide a
crossing spiral compressor/turbine or pump/turbine integrated with
a permanent magnet motor/generator and utilized with a
bi-directional inverter that is efficient in fluid dynamic energy
conversion and efficient in electrical power utilization and
generation over the entire operating ranges for pressure, flow and
speed. A bi-directional inverter, sometimes called a four quadrant
inverter, is capable of putting power into the permanent magnet
motor or taking power out of the permanent magnet generator.
[0090] It is another aspect of the present invention to provide a
compressor/turbine or pump/turbine that can operate from no flow
with maximum pressure change across the machine to full flow with
minimum pressure change across the machine with no instabilities or
discontinuities in the pressure/flow characteristics.
[0091] It is another aspect of the present invention to provide a
compressor/turbine or pump/turbine integrated with a permanent
magnet motor/generator and utilized with a bi-directional inverter
that can quickly and continuously adjust its process fluid
throughput flow rate to match requirements.
[0092] It is another aspect of the present invention to provide a
crossing spiral compressor or pump integrated with a permanent
magnet motor/generator and utilized with a bi-directional inverter
wherein gaseous fuels for a turbogenerator are compressed or
expanded.
[0093] It is another aspect of the present invention to provide a
crossing spiral compressor or pump integrated with a permanent
magnet motor/generator and utilized with a bi-directional inverter
wherein liquid fuels for a turbogenerator are pressurized or
depressurized.
[0094] It is another aspect of the present invention to provide a
crossing spiral compressor or pump integrated with a permanent
magnet motor/generator and utilized with a bi-directional inverter
wherein gaseous fuel for a turbogenerator is compressed or expanded
to precisely control the fuel pressure or mass flow required by the
turbogenerator.
[0095] It is another aspect of the present invention to provide a
crossing spiral compressor or pump integrated with a permanent
magnet motor/generator and utilized with a bi-directional inverter
wherein liquid fuel for a turbogenerator is pressurized or
depressurized to precisely control the fuel pressure or mass flow
required by the turbogenerator.
BRIEF DESCRIPTION OF THE DRAWINGS
[0096] Having thus described the present invention in general
terms, reference will now be made to the accompanying drawings in
which:
[0097] FIG. 1 is an end view of the crossing spiral compressor/pump
of the present invention;
[0098] FIG. 2 is a sectional view of the crossing spiral
compressor/pump of FIG. 1 taken along line 2-2 of FIG. 1;
[0099] FIG. 3 is a perspective view of the spiral rotor of the
crossing spiral compressor/pump of the FIGS. 1 and 2;
[0100] FIG. 4 is an enlarged end view of the spiral rotor of FIG.
3;
[0101] FIG. 5 is a perspective view of the stator of the crossing
spiral compressor/pump of the FIGS. 1 and 2;
[0102] FIG. 6 is a cross sectional view of the stator of FIG. 5
taken along line 6-6 of FIG. 5;
[0103] FIG. 7 is an enlarged sectional view of a portion of the
spiral rotor of FIGS. 3 and 4 showing an opposed aligned stator
channel;
[0104] FIG. 8 is an enlarged sectional view of a portion of the
spiral rotor of FIGS. 3 and 4 showing an opposed offset stator
channel;
[0105] FIG. 9 is an enlarged sectional view of a portion of the
spiral rotor of FIGS. 3 and 4 showing rotor channel flow at a
medium back pressure;
[0106] FIG. 10 is an enlarged sectional view of a portion of the
spiral rotor of FIGS. 3 and 4 showing rotor channel flow at a high
back pressure;
[0107] FIG. 11 is an enlarged sectional view of a portion of the
spiral rotor of FIGS. 3 and 4 showing rotor channel flow at a low
back pressure;
[0108] FIG. 12 is a sectional view of an alternate crossing spiral
compressor/pump of the present invention having fluid entry at the
center of the compressor/pump;
[0109] FIG. 13 is a plan view of the spiral rotor of the alternate
crossing spiral compressor/pump of FIG. 12;
[0110] FIG. 14 is an end view of the spiral rotor of the alternate
crossing spiral compressor/pump of FIG. 12;
[0111] FIG. 15 is a sectional view of the rotor and stator of the
alternate crossing spiral compressor/pump of FIG. 12;
[0112] FIG. 16 is a sectional view of an alternate crossing spiral
compressor/pump of the present invention having fluid entry from
both ends of the compressor/pump;
[0113] FIG. 17 is a plan view of the spiral rotor of the alternate
crossing spiral compressor/pump of FIG. 16;
[0114] FIG. 18 is an end view of the spiral rotor of the alternate
crossing spiral compressor/pump of FIG. 16;
[0115] FIG. 19 is a sectional view of the stator of the alternate
crossing spiral compressor/pump of FIG. 16;
[0116] FIG. 20 is a perspective view, partially cut away, of a
turbogenerator for use with the crossing spiral compressor/pump of
the present invention;
[0117] FIG. 21 is a detailed block diagram of a power controller
for the turbogenerator of FIG. 20;
[0118] FIG. 22 is a detailed block diagram of the power converter
in the power controller illustrated in FIG. 21;
[0119] FIG. 23 is an enlarged sectional view of a portion of the
spiral rotor and housing bore showing a change of size of the rotor
fluid flow channel from one end of the rotor to the other;
[0120] FIG. 24 is an enlarged sectional view of a portion of the
spiral rotor and housing bore showing a change in pitch in the
rotor channel flow from the entry point to the exit point; and
[0121] FIG. 25 is an enlarged sectional view of a portion of the
spiral rotor and housing bore showing a change in rotor channel
flow cross-sectional area from the entry point to the exit
point.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0122] As illustrated in FIGS. 1 and 2, the crossing spiral
compressor/pump 10 of the present invention generally comprises a
fluid stator or stator housing 12 having a central bore within
which a fluid rotor 14 is disposed to rotate. An end cap 16, having
an inlet 18 and outlet 20 rotatably supports one end of the rotor
14 in duplex bearings 22 while the other end of the rotor 14 is
rotatably supported by single bearing 24 held in the opposite end
cap 26. The end cap inlet 18 communicates with the crossing spiral
compressor/pump inlet 19 while the end cap outlet 20 communicates
with the crossing spiral compressor/pump outlet 21.
[0123] The rotor 14 is driven by an electric motor 30, preferably a
permanent magnet motor, having stator windings 32 disposed around a
permanent magnet rotor 34, which is an extension of rotor 14. The
motor 30 is in a recessed portion 36 of the fluid flow stator 12.
Disposed around the stator 12 is an elongated cylindrical cooling
housing 40 to form an annular passage 42 which includes a plurality
of radially extending fins 43 for cooling air. A fan 44 having a
plurality of blades 46 in a housing 45 attached to the cooling
housing 40 forces cooling air through the annular passage 42 and
fins 43 to cool the crossing spiral compressor/pump 10 and electric
motor 30.
[0124] The rotor 14 is illustrated in FIGS. 3 and 4 and is
generally cylindrical with a plurality of spiral blades 48. Spiral
grooves or channels 50 are formed between adjacent blades 48. The
pitch angle of the spiral blades 48 is generally illustrated by way
of example as approximately 45 degrees.
[0125] The stator 12 is illustrated in FIGS. 5 and 6. The stator 12
is generally cylindrical with a central bore having a plurality of
spiral grooves or channels 52 separated by narrow blades 53. The
stator housing bore channels 52 normally have the same pitch as the
rotor channels 50 but spiral in the reverse or opposite
direction.
[0126] FIGS. 7 and 8 illustrate the relationship of the rotating
rotor channels 50 and the stator channels 52. FIG. 7 shows the
stator housing bore channels 52 generally aligned with the rotor
channels 50 wherein the fluid flow pattern normal to the rotor's
rotational axis is elliptical, while FIG. 8 shows the stator
housing bore channels 52 generally offset from the rotor channels
50 wherein the fluid flow pattern is more complex.
[0127] FIGS. 9-11 illustrate the flow of fluid in the rotor
channels 50: FIG. 9 at a medium back pressure; FIG. 10 at a high
backpressure; and FIG. 11 at a low backpressure. The diffusion
section 60, 60' and 60" where the fluid is decelerated, is larger
with a high back pressure and smaller with a low back pressure,
while the kinetic and velocity addition section 62, 62' and 62",
where the fluid is accelerated, is larger at low back pressure and
smaller at high back pressure.
[0128] The crossing spiral compressor/pump 10 runs at low enough
speed that it can be easily run on greaseback ball bearings (or
other grease lubricated rolling contact bearings) driven by a
permanent magnet motor. The rotor 14 is a long cylinder and with a
compression length of e.g. 10 inches and would have a rotor
diameter of e.g. 1.375 inches. This produces 20 parallel flow paths
in the rotor where the spiral goes one way, say clockwise, and a
like spiral pattern in a stationary stator bore which goes
counter-clockwise. The two spirals of the rotor channel 50 and
stator channel 52 go in opposite directions.
[0129] The crossing spiral compressor/pump 10 is a type of
compressor that has a single rotor 14 that allows the gas to be
accelerated by the rotor 14 which puts kinetic energy into the gas
and then diffuses the gas's velocity or kinetic energy into
potential or pressure energy in the stator 12 and then repeats this
process a fifty times or so from the time the gas enters the
compressor 10 until the time it leaves. Fifty stages of compression
can be achieved with a single rotor 14 with each stage of
compression only having a pressure ratio of e.g. 1.03, (something
that is very easy to achieve).
[0130] The gas enters the area between the rotor 14 and the stator
12 which has a small clearance, on the order of four and a half
thousandths of an inch, and the gas is accelerated by the rotor
blades 48 which, if rotating clockwise, will take the gas
clockwise. While there will be a slight backward slippage, the gas
will be driven into a rotational motion by fluid shear forces
because the stator channel 52 is not rotating. This essentially
causes the gas to spin and the gas in the rotor 14 goes into the
stator 12 and the gas in the stator 12 is driven into the rotor
14.
[0131] Every time the gas spirals clockwise along the rotor channel
50, and crosses the flow coming from a stator channel 52 that is
going counter-clockwise, the gas in the two channels 50, 52
exchanges by rotation and exchange momentum. Each time this
rotation occurs the gas from the stator 12 goes into the rotor 14
and its velocity energy is diffused and converted into pressure
energy in the first half of that rotor channel 50. Then in the
second half of the rotor channel 50 the gas is accelerated into a
local reverse flow. The gas then leaves the rotor 14 and goes into
the stator 12 where it is diffused and the fluid velocity energy
induced by rotor 14 is converted into pressure energy, and in the
second half of the stator 12 the gas is reaccelerated in a reverse
direction by a nozzle effect and is then made available for the
rotor 14. This condition is particularly true at high pressure head
and low flow.
[0132] Essentially, there are two quarters of rotation where
diffusion is occurring, one on the rotor 14 and one on the stator
12, and two quarters of rotation where circumferential acceleration
of the fluid is occurring, one on the rotor 14 and one on the
stator 12. Now the gas will typically rotate 50 times between the
inlet 19 and outlet 21 which gives it a hundred times to be
accelerated and a hundred times to be diffused.
[0133] The number of parallel channels that are in the rotor 14,
which are spiraled in one direction, and the number of channels in
the stator 12, which are spiraled in the reverse direction, can be
addressed in terms of the aspect ratio of the interface between the
stator channel 52 and rotor channel 50 in which the gas will be
rotating. While the channels 50, 52 are shown as half circles, the
gas path is actually an elliptical path so the gas is not able to
spin really quickly because it's not a round path. If the grooves
are made deeper into the rotor 14 and into the stator 12, (or to
state it another possibly more accurate way, if the width of the
grooves is made less but the depth of the grooves is kept the same)
a circular cross section at the interface of the two channels (both
stator and rotor) would be achieved thus easing the gas's rotation.
This should produce higher pressure and higher efficiency
operation. So there is a variable in the design of this kind of
compressor which can be characterized as the number of parallel
channels for a given depth and a given diameter of the rotor, which
effectively determines the aspect ratio of the channels.
[0134] The ratio of depth to width of the channels should optimize
depending upon the pitch angle of the channels which is a second
variable. A third variable is the forward sloping of the blades
which separate each channel and for both the stator channels and
the rotor channels.
[0135] A fourth variation is the reduction in the cross sectional
area of the channels as you go from the low pressure end of the
compressor to the high pressure end, which is to maintain constant
blade width and would also entail a tightening of the pitch angle
by reducing the groove width and depth. Eventually this results in
a finer pitch on the high pressure end and a coarser pitch on the
low pressure end.
[0136] Now the configuration of the compressor with all these
parameters might be characterized as follows: at the low pressure
end (typically the inlet) of the channels there would be a coarse
angle from normal to the axis of the rotor. As the spiral proceeds,
the cross sectional area of the spirals will decrease towards the
high-pressure end and the pitch will become finer. The blades
separating the channels can be leaning forward into the direction
of motion of the rotor and leaning forward towards the direction
from which the rotor comes for the stator. The overall angle at the
channels, both the inlet and outlet, is also a parameter and can be
optimized as is the linearity of the change in the cross section
area going from the low-pressure end to the high-pressure end.
[0137] While the flow of fluid in the crossing spiral
compressor/pump can be in a single direction from one end of the
compressor/pump to the other end as shown in FIGS. 1 and 2, the
fluid can be introduced at the midpoint of the compressor/pump and
discharged at both ends as illustrated in FIGS. 12-15 or can be
introduced at both ends and discharged from the midpoint of the
compressor/pump ad illustrated in FIGS. 16-19.
[0138] In the first bi-directional embodiment of FIGS. 12-15, the
fluid enters the crossing spiral compressor/pump 10' through an
inlet 64 in the end cap 16', through the inlet 65 in the stator 12'
and then into the radial inlet 66 at the midpoint of the compressor
pump 10'. It then proceeds in the space between the rotor 14' and
stator 12' in both directions from the midpoint radial inlet
66.
[0139] The fluid travelling to the right from the radial inlet 66
is collected in radial outlet 67 and proceeds to the left in stator
outlet 68. The fluid travelling to the left from the radial inlet
66 is collected in the end cap radial outlet 69 which also receives
the fluid from the stator outlet 68. The combined compressed fluid
exits the compressor/pump 10' through outlet 70.
[0140] As illustrated in FIGS. 13 and 14, the rotor 14' includes a
first (left-end) spiral section 71 and a second (right-end) spiral
section 72 on either side of central inlet 66. The first or
left-end spiral section 71 spirals in one direction, shown as
counterclockwise, while the second or right-end spiral section 72
spirals in the opposite direction, shown as clockwise.
[0141] The stator 12', illustrated in FIG. 15, includes a central
bore having a first or left-end spiral section 73 and a second or
right-end counter section 74 on either side of central inlet 66.
The first or left-end spiral section 72 has a clockwise spiral
while the second or right-end counter section 74 has an opposite or
counterclockwise spiral. The left-end counter clockwise spiral
section 71 of the rotor 14' rotates within the left-end clockwise
section spiral section 73 of the stator 12' while the right-end
clockwise spiral section 72 of the rotor 14' rotates within the
right-end counter clockwise section spiral section 74 of the stator
12'.
[0142] In the second bi-directional embodiment of FIGS. 16-19, the
fluid enters the crossing spiral compressor/pump 10" through inlets
80 and 81 at opposite ends of the rotor 14" and stator 12". The
fluid then proceeds into the space between the rotor 14" and stator
12" from the left-end and through the inlet 79 in stator 12" to the
right-end where this fluid proceeds in the space between the rotor
14" and stator 12". The fluid proceeds in both directions towards
the midpoint radial outlet 82 and the compressed fluid is
discharged through stator outlet 83 and end cap outlet 84.
[0143] As illustrated in FIGS. 17 and 18, the rotor 14" includes a
first (left-end) spiral section 86 and a second (right-end) spiral
section 87 on either side of central outlet 82. The first or
left-end spiral section 86 spirals in one direction, shown as
counterclockwise, while the second or right-end spiral section 87
spirals in the opposite direction, shown as clockwise.
[0144] The stator 12", illustrated in FIG. 19, includes a central
bore having a first or left-end spiral section 90 and a second or
right-end counter section 91 on either side of central radial
outlet 82. The first or left-end spiral section 90 has a clockwise
spiral while the second or right-end counter section 91 has on
opposite or counterclockwise spiral. The left-end counter clockwise
spiral section 86 of the rotor 14" rotates within the left-end
clockwise section spiral bore 90 of the stator 12" while the
right-end clockwise spiral section 87 of the rotor 14" rotates
within the right-end counter clockwise section spiral bore 91 of
the stator 12".
[0145] With the fluid flow entering at the mid point of the rotor
and stator housing bore fluid flow channels and exiting at both
ends of the fluid flow channels (or alternately, enters at both
ends and exits at the mid point of the rotor and stator housing
bore), the bi-directional fluid flow path results in the
possibility of generating no fluid generated thrust load on the
rotor bearings. This also permits the utilization of a larger
diameter for the rotor that allows the length of the rotor to be
reduced.
[0146] One possible use for the crossing spiral compressor/pump 10
is to compress natural gas or other gaseous fuel for a machine such
as a turbogenerator. The crossing spiral compressor/pump 10 can
take natural gas that is essentially at atmospheric pressure and
can boost the natural gas to a pressure over 30 pounds per square
inch (PSI) gauge. All of this can be accomplished with a compressor
that does not have rubbing surfaces, does not have oil lubrication,
and does not have seals that can wear. To do this with a
centrifugal compressor would require very high tip speed, large
diameters and high rpms, and would have inherently large leakages
from the impeller blades to the scroll.
[0147] A permanent magnet turbogenerator 110 is illustrated in FIG.
20 as an example of a turbogenerator for use with the crossing
spiral compressor/pump of the present invention. The permanent
magnet turbogenerator 110 generally comprises a permanent magnet
generator 112, a power head 113, a combustor 114 and a recuperator
(or heat exchanger) 115.
[0148] The permanent magnet generator 112 includes a permanent
magnet rotor or sleeve 116, having a permanent magnet disposed
therein, rotatably supported within stator 118 by a pair of spaced
journal bearings. Radial stator cooling fins 125 are enclosed in an
outer cylindrical sleeve 127 to form an annular air flow passage
which cools the stator 118 and thereby preheats the air passing
through on its way to the power head 113.
[0149] The power head 113 of the permanent magnet turbogenerator
110 includes compressor 130, turbine 131, and bearing rotor 136
through which the tie rod 129 passes. The compressor 130, having
compressor impeller or wheel 132 which receives preheated air from
the annular air flow passage in cylindrical sleeve 127 around the
permanent magnet motor stator 118, is driven by the turbine 131
having turbine wheel 133 which receives heated exhaust gases from
the combustor 114 supplied with air from recuperator 115. The
compressor wheel 132 and turbine wheel 133 are rotatably supported
by bearing shaft or rotor 136 having radially extending bearing
rotor thrust disk 137.
[0150] The bearing rotor 136 is rotatably supported by a single
journal bearing within the center bearing housing while the bearing
rotor thrust disk 137 at the compressor end of the bearing rotor
136 is rotatably supported by a bilateral thrust bearing. The
bearing rotor thrust disk 137 is adjacent to the thrust face of the
compressor end of the center bearing housing while a bearing thrust
plate is disposed on the opposite side of the bearing rotor thrust
disk 137 relative to the center housing thrust face.
[0151] Intake air is drawn through the permanent magnet generator
112 by the compressor 130 that increases the pressure of the air
and forces it into the recuperator 115. In the recuperator 115,
exhaust heat from the turbine 131 is used to preheat the air before
it enters the combustor 114 where the preheated air is mixed with
fuel and burned. The combustion gases are then expanded in the
turbine 131 which drives the compressor 130 and the permanent
magnet rotor 116 of the permanent magnet generator 112 which is
mounted on the same shaft as the turbine wheel 133. The expanded
turbine exhaust gases are then passed through the recuperator 115
before being discharged from the turbogenerator 110.
[0152] The system has a steady-state turbine exhaust temperature
limit, and the turbogenerator operates at this limit at most speed
conditions to maximize system efficiency. This turbine exhaust
temperature limit is decreased at low ambient temperatures to
prevent engine surge.
[0153] Referring to FIG. 21, the power controller 140, which may be
digital, provides a distributed generation power networking system
in which bi-directional (i.e. reconfigurable) power converters (or
inverters) are used with a common DC bus 154 for permitting
compatibility between one or more energy components. Each power
converter operates essentially as a customized bi-directional
switching converter configured, under the control of power
controller 140, to provide an interface for a specific energy
component to DC bus 154. Power controller 140 controls the way in
which each energy component, at any moment, with sink or source
power, and the manner in which DC bus 154 is regulated. In this
way, various energy components can be used to supply, store and/or
use power in an efficient manner. The energy components, as shown
in FIG. 21, include an energy source 142 such as the turbogenerator
110, utility/load 148, and storage device 150, which can simply be
a battery.
[0154] A detailed block diagram of power converter 144 in the power
controller 140 of FIG. 21 is illustrated in FIG. 22. The energy
source 142 is connected to DC bus 154 via power converter 144.
Energy source 142 may produce AC that is applied to power converter
144. DC bus 154 connects power converter 144 to utility/load 148
and additional energy components 166. Power converter 144 includes
input filter 156, power switching system 158, output filter 164,
signal processor 160 and main CPU 162.
[0155] In operation, energy source 142 applies AC to input filter
156 in power converter 144. The filtered AC is then applied to
power switching system 158 which may conveniently be a series of
insulated gate bipolar transistor (IGBT) switches operating under
the control of signal processor 160 which is controlled by main CPU
162. The output of the power switching system 158 is applied to
output filter 164 which then applies the filtered DC to DC bus
154.
[0156] Each power converter 144, 146, and 152 operates essentially
as a customized, bi-directional switching converter under the
control of main CPU 162, which uses signal processor 160 to perform
its operations. Main CPU 162 provides both local control and
sufficient intelligence to form a distributed processing system.
Each power converter 144, 146, and 152 is tailored to provide an
interface for a specific energy component to DC bus 154. Main CPU
162 controls the way in which each energy component 142, 148, and
150 sinks or sources power and DC bus 154 is regulated at any time.
In particular, main CPU 162 reconfigures the power converters 144,
146, and 152 into different configurations for different modes of
operation. In this way, various energy components 142, 148, and 150
can be used to supply, store and/or use power in an efficient
manner.
[0157] In the case of a turbogenerator 110 as the energy source
142, a conventional system regulates turbine speed to control the
output or bus voltage In the power controller 140, the
bi-directional controller functions independently of turbine speed
to regulate the bus voltage.
[0158] FIGS. 21 and 22 generally illustrate the system topography
with the DC bus 154 at the center of a star pattern network. In
general, energy source 142 provides power to DC bus via power
converter 144 during normal power generation mode. Similarly,
during power generation, power converter 146 converts the power on
DC bus 154 to the form required by utility/load 148. During utility
start up, power converters 144 and 146 are controlled by the main
processor to operate in different manners. For example, if energy
is needed to start the turbogenerator 110, this energy may come
from load/utility 148 (utility start) or from energy source 150
(non-utility start). During a utility start up, power converter 146
is required to apply power from load 148 to DC bus for conversion
by power converter 144 into the power required by the
turbogenerator 110 to start up. During utility start, the
turbogenerator 110 is controlled in a local feedback loop to
maintain the turbine revolutions per minute (RPM). Energy storage
150 is disconnected from DC bus while load/utility grid regulates
V.sub.DC on DC bus 154.
[0159] Similarly, in a non-utility start, the power applied to DC
bus 154 from which turbogenerator 110 may be started, may be
provided by energy storage 150. Energy storage 150 has its own
power conversion circuit in power converter 152, which limits the
surge current into the DC bus 154 capacitors, and allows enough
power to flow to DC bus 154 to start turbogenerator 110. In
particular, power converter 156 isolates the DC bus 154 so that
power converter 144 can provide the required starting power from DC
bus 154 to turbogenerator 110.
[0160] A more detailed description of the power controller can be
found in U.S. patent application Ser. No. 207,817, filed Dec. 8,
1998 by Mark G. Gilbreth et al, entitled "Power Controller",
assigned to the same assignee as this application and hereby
incorporated by reference.
[0161] FIGS. 23, 24, and 25 illustrate alternative channel
arrangements where the size of the channels varies from entry point
to exit point (FIG. 23), the pitch of the channels varies from
entry point to exit point (FIG. 24), and the channel fluid flow
entry point blade shape varies (FIG. 25).
[0162] While specific embodiments of the invention have been
illustrated and described, it is to be understood that these are
provided by way of example only and that the invention is not to be
construed as being limited thereto but only by the proper scope of
the following claims.
* * * * *