Note: Descriptions are shown in the official language in which they were submitted.
THRUST BEARING SYSTEM AND METHOD FOR OPERATING THE SAME
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Application No.
62/735,868 filed on September 25, 2018.
TECHNICAL FIELD
[0002] The present disclosure relates generally to a fluid machine,
and, more
specifically, to thrust bearing lubrication for axial thrust force
compensation within the fluid
machine suitable for high contaminant or gas bubble environments.
BACKGROUND
[0003] The statements in this section merely provide background
information related
to the present disclosure and may not constitute prior art.
[0004] Rotating fluid machines are used in many applications for many
processes.
Lubrication for a rotating fluid machine is important. Various types of fluid
machines use a
thrust bearing that is lubricated by the pumpage. Adequate flow of pumpage
should be supplied
to obtain proper lubrication. Fluid machines are used under various
conditions. During normal
operating conditions, lubrication may be relatively easy. However, under
various operating
conditions contaminants or bubbles may be present in the pumpage. Contaminants
and pumpage
may affect the lubrication provided by the thrust bearing. Losing lubrication
may cause damage
the fluid machine. Air entrainment or debris within the pumpage may cause
upset conditions.
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[0005] Referring now to FIG. 1, a hydraulic pressure booster (HPB) 10
is one type of
fluid machine. The hydraulic pressure booster 10 is part of an overall
processing system 12 that
also includes a process chamber 14. Hydraulic pressure boosters may include a
pump portion 16
and a turbine portion 18. A common shaft 20 extends between the pump portion
16 and the
turbine portion 18. The HPB 10 may be free-running which means that it is
solely energized by
the turbine and will run at any speed where the equilibrium exists between a
turbine output
torque and the pump input torque. The rotor or shaft 20 may also be connected
to an electric
motor to provide a predetermined rotational rate.
[0006] The hydraulic pressure booster 10 is used to boost the process
feed stream
using energy from another process stream which is depressurized through the
turbine portion 18.
[0007] The pump portion 16 includes a pump impeller 22 disposed within
a pump
impeller chamber 23. The pump impeller 22 is coupled to the shaft 20. The
shaft 20 is
supported by a bearing 24. The bearing 24 is supported within a casing 26.
Both the pump
portion 16 and the turbine portion 18 may share the same casing structure.
[0008] The pump portion 16 includes a pump inlet 30 for receiving
pumpage and a
pump outlet 32 for discharging fluid to the process chamber 14. Both of the
pump inlet 30 and
the pump outlet 32 are openings within the casing 26.
[0009] The turbine portion 18 may include a turbine impeller 40
disposed within a
turbine impeller chamber 41. The turbine impeller 40 is rotatably coupled to
the shaft 20. The
pump impeller 22, the shaft 20 and the turbine impeller 40 rotate together to
form a rotor 43.
Fluid flow enters the turbine portion 18 through a turbine inlet 42 through
the casing 26. Fluid
flows out of the turbine portion 40 through a turbine outlet 44 also through
the casing 26. The
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turbine inlet 42 receives high-pressure fluid and the outlet 44 provides fluid
at a pressure reduced
by the turbine impeller 40.
[0010] The
impeller 40 is enclosed by an impeller shroud. The impeller shroud
includes an inboard impeller shroud 46 and an outboard impeller shroud 48.
During operation
the pump impeller 22, the shaft 20 and the turbine impeller 40 are forced in
the direction of the
turbine portion 18. In Fig. 1, this is in the direction of the axial arrow 50.
The impeller shroud
48 is forced in the direction of a thrust bearing 54.
[0011] The
thrust bearing 54 may be lubricated by pumpage fluid provided from the
pump inlet 30 to the thrust bearing 54 through an external tube 56. A gap or
layer of lubricating
fluid may be disposed between the thrust bearing 54 and outboard impeller
shroud which is small
and is thus represented by the gap 55 therebetween. A filter 58 may be
provided within the tube
to prevent debris from entering the thrust bearing 54. At start-up, the
pressure in the pump
portion 16 is greater than the thrust bearing and thus lubricating flow will
be provided to the
thrust bearing 54. During operation, the pressure within the turbine portion
18 will increase and
thus fluid flow to the thrust bearing 54 may be reduced. The thrust bearing 54
may have
inadequate lubricating flow during operation. Also, when the filter 58 becomes
clogged, flow to
the thrust bearing 54 may be interrupted. The thrust bearing 54 generates a
force during normal
operation in the opposite direction of arrow 50.
[0012]
Referring now to FIG. 2, a first example of a hydraulic-pressure booster
10" is illustrated. In this example, the common components from Fig. 1 are
provided with the
same reference numerals are not described further. In this example, a hollow
shaft 20' is used
rather than the solid shaft illustrated in Fig. 1. The hollow shaft 20' has a
shaft passage 70 that is
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used for passing pumpage from the pump impeller chamber 23 of the pump portion
16 to the
turbine portion 18. The passage 70 may provide pumpage from the pump inlet 30.
[0013] The inboard shroud 46' includes radial passages 72. The radial
passages 72
are fluidically coupled to the shaft passage 70. Although only two radial
passages 72 are
illustrated, multiple radial passages may be provided.
[0014] The impeller 40' may include vanes 76A-D as is illustrated in
Fig. 3. The
impeller 40' includes axial passages 74. The axial passages 74 may be provided
through vanes
76A and 76C of the impeller 40'. The axial passages are parallel to the axis
of the HPB 10'' and
the shaft 20'. The axial passages 74 extend partially through the inner
impeller shroud 46' and
entirely through the outboard impeller shroud 48'. The axial passages 74
terminate adjacent to
the thrust bearing 54. Again the gap 55 between the outboard impeller shroud
48' and the thrust
bearing 54 is small and thus is represented by a line in the Figure. The
lubrication path for the
thrust bearing 54 includes the shaft passage 70, the radial passages 72 and
the axial turbine
impeller passages 74.
[0015] In operation, at start-up pressure within the pump portion 16
is higher than the
turbine portion 18. Fluid within the pump portion travels through the shaft
passage 70 to the
radial passages 72 and to the axial passage 74. When the fluid leaves the
axial passage 74, the
fluid is provided to the thrust bearing 54. More specifically, the fluid
lubricates the space or gap
55 between the thrust bearing 54 and the outboard impeller shroud 48'. The
thrust bearing 54
generates an inboard axial force in response to the lubricating fluid in the
opposite direction of
arrow 50.
[0016] The highest pressure in the pumpage occurs in the pump inlet 30
during
startup. Passages downstream of the pump inlet are at lower pressure and thus
fluid from the
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_
pump portion 16 flows to the turbine portion 18. Consequently, pumpage from
the inlet is high
during the startup. During shutdown of the equipment, the same factors apply
due to the
differential and pressure between the pump and the turbine. During normal
operation, the
highest pressure is no longer in the pump inlet but is at the pump outlet 32.
Due to the
arrangement of the lubrication passages, the pressure increases in the pumpage
due to a pressure
rise occurring in the radial passage 72 due to a centrifugal force generated
by the rotation of the
turbine impeller 40'. The amount of pressure generation is determined by the
radial length of the
radial passages 72 and the rate of the rotor rotation. Consequently, pumpage
is provided to the
thrust bearing at the startup, normal operation and shutdown of the hydraulic
pressure booster
10".
[0017] Referring now to FIG. 3, the impeller 40' is illustrated having
four impeller
vanes 76A-76D. Various numbers of vanes may be provided. The vanes extend
axially relative
to the axis of the shaft 20'. More than one impeller vane may have an axial
passage 74. The
axial passage 74 extends through the vanes 76 and the inboard impeller shroud
46' sufficient to
intercept radial passage 72 and the outboard impeller shroud 48' which are
illustrated in Fig. 2.
[0018] It should be noted that the process chamber 14 is suitable for
various types of
processes including a reverse osmosis system. For a reverse osmosis system,
the process
chamber may have a membrane 90 disposed therein. A permeate output 92 may be
provided
within the process chamber for desalinized fluid to flow therefrom. Brine
fluid may enter the
turbine inlet 42. Of course, as mentioned above, various types of process
chambers may be
provided for different types of processes including natural gas processing and
the like.
[0019] Referring now to FIG. 4, an example similar to that of Fig. 2
is illustrated and
is thus provided the same reference numerals. In this example, a hydraulic
pressure booster
CA 3056662 2019-09-25
10" having a deflector 110 is provided within the pump inlet 30. The deflector
110 may be
coupled to the pump impeller 22 using struts 112. The struts 112 may hold the
deflector 110
away from the pump impeller so that a gap is formed therebetween that allows
fluid to flow into
the shaft passage 70.
[0020] The deflector 110 may be cone-shaped and have an apex 114
disposed along
the axis of the shaft 20'. The cone shape of the deflector 110 will deflect
debris in the pumpage
into the pump impeller 22 and thus prevent passage of debris into the shaft
passage 70. Unlike
the filter 58 illustrated in Fig. 1, the debris is deflected away from the
shaft passage 70 and thus
will not clog the shaft passage 70.
[0021] Referring now to FIG. 5, the turbine portion 18 is illustrated
having another
example of a thrust bearing 54'. The thrust bearing 54' may include an outer
land 210 and an
inner land 212. A fluid cavity 214 is disposed between the outer land 210, the
inner land 212
and the outer shroud 48'. It should be noted that the thrust bearing 54' of
Fig. 5 may be included
in the examples illustrated in Figs. 2 and 4.
[0022] The outer land 210 is disposed adjacent to the annular
clearance 60. The inner
land 212 is disposed adjacent to the turbine outlet 44. The thrust bearing 54'
may be annular in
shape and thus the outer land 210 and inner land 212 may also be annular in
shape.
[0023] The cavity 214 may receive pressurized fluid from the pump
portion 16
illustrated in Figs. 2 and 4. That is, pumpage may be received through the
shaft passage 70, the
radial passages 72 and the axial passages 74.
[0024] Slight axial movements of the shaft 20 in the attached impeller
shroud 48' may
cause variations in the axial clearance 220 between the lands 210 and 212
relative to the outer
shroud 48'. If the axial clearances 220 increase, the pressure in the fluid
cavity 214 decreases
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due to an increase of leakage through the clearances 220. Conversely, if the
axial gap of the
clearance 220 decreases, the pressure will rise in the fluid cavity 214. The
pressure variation
counteracts the variable axial thrust generated during operation and ensures
that the lands 210
and 212 do not come into contact with the impeller shroud 48'.
[0025] The reduction in pressure is determined by the flow resistance
in the passages
70-74. The passages are sized to provide a relationship between the rate of
leakage and the
change in pressure in the fluid cavity 214 as a function of the axial
clearance. The radial location
of the passage 74 determines the amount of centrifugally generated pressure
rise and is
considered in ensuring an optimal leakage in addition to the diameters of the
flow channel.
Excessive leakage flow may impair the efficiency and insufficient fluid flow
will allow
clearances to be too small and allow frictional contact during operation.
[0026] The pressure in the fluid cavity is higher than the turbine
outlet 44 and the
pressure in the outer diameter of the impeller in the annular clearance 60
when the passage 74 is
at the optimal radial location. Leakage will thus be out of cavity 214 to
allow a desired pressure
variation within the fluid cavity 214.
[0027] Referring now to FIG. 6A, an example similar to that of Fig. 5
is illustrated.
The inner land 212 is replaced by a bushing 230. The bushing 230 may form a
cylindrical
clearance relative to the impeller wear ring 232. The fluid cavity 214 is thus
defined between the
wear ring 232, the bushing 230 and the outer land 210.
[0028] Referring now to FIG. 6B, vane 240 of an impeller 242 having
curvature in
the axial plane as well as the radial plane is illustrated. The impeller 242
may be used in a mixed
flow design. In this example, the outer land 210' and inner land 212' are
formed according to the
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shape of the impeller 242. The fluid cavity 214' may also be irregular in
shape between the outer
land 210' and the inner land 212'.
[0029] The fluid passage 250 provides fluid directly to the fluid
cavity 214' in a
direction at an angle to the longitudinal axis of the fluid machine and shaft
20'. Thus, the radial
passages 72 and axial passages 74 are replaced with the diagonal passage 250.
The diagonal
passage 250 may enter the fluid cavity 214' at various locations including
near the land 212' or at
another location such as near land 210'. Various places between land 210' and
212' may also
receive the diagonal passage 250.
[0030] Referencing now to FIG. 7, another example of a hydraulic
pressure booster
10Iv is set forth. In this example, the center bearing 24 provides radial
support for the shaft 20Iv
that has a central axial shaft passage 710. The central axial shaft passage
710 communicates
fluid from the pump portion 16 to the turbine portion 18. In particular, the
central axial shaft
passage 710 communicates fluid to an impeller passage having radial extending
passages 720
disposed in a first shroud portion 46 of the impeller 40. The impeller 40 and
a second shroud
portion 48 are located on the axial ends thereof. The radially extending
passages 720 fluidically
communicate with axially extending passages 726. The axially extending
passages 726
fluidically communicate with a thrust bearing 728. The thrust bearing 728 is
defined as being a
rotating thrust face 730 of the second shroud portion 48, a stationary thrust
face 732 of the thrust
wear ring 734. The thrust wear ring 734 is disposed around the turbine outlet
44. The thrust
bearing 728 is also defined by an inner land 736 and an outer land 738.
[0031] The turbine impeller 40 has vanes 724 that have the axially
extending
passages disposed therein.
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[0032] Further areas of applicability will become apparent from the
description
provided herein. It should be understood that the description and specific
examples are intended
for purposes of illustration only and are not intended to limit the scope of
the present disclosure.
SUMMARY
[0033] This section provides a general summary of the disclosure, and
is not a
comprehensive disclosure of its full scope or all of its features.
[0034] The present disclosure provides an improved method for
lubricating a rotating
process machine during operation. The system provides pumpage to the thrust
bearing over the
entire operating range of the device.
[0035] In one aspect of the disclosure, a fluid machine comprises a
pump portion
having a pump impeller chamber, a pump inlet and a pump outlet, a turbine
portion having a
turbine impeller chamber, a turbine inlet and a turbine outlet and a shaft
extending between the
pump impeller chamber and the turbine impeller chamber. The fluid machine also
includes a
first bearing and a second bearing spaced apart to form a balance disk
chamber. A balance disk is
coupled to the shaft and is disposed within the balance disk chamber and a
turbine impeller
coupled to the impeller end of the shaft disposed within the impeller chamber.
A first thrust
bearing is formed between the balance disk and the first bearing. The thrust
bearing receives
fluid from at least one of the pump inlet or the turbine outlet.
[0036] In another aspect of the disclosure, a method for operating a
fluid machine
includes communicating fluid from a pump outlet or a turbine inlet to a thrust
bearing formed by
a balance disk coupled to a shaft, rotating the balance disk between a first
bearing and a second
bearing, and generating an axial force in response to communicating fluid in
response to
communicating and generating.
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[0037] In another aspect of the disclosure, a fluid machine assembly
comprises a
pump portion having a pump impeller chamber, a pump inlet and a pump outlet. A
turbine
portion has a turbine impeller chamber, a turbine inlet and a turbine outlet.
A center bearing is
disposed between the pump impeller chamber and turbine impeller chamber. The
center bearing
has a first end surface defining a stationary thrust face within the pump
impeller chamber. A
shaft extends between the pump impeller chamber and the turbine impeller
chamber through the
center bearing. A turbine impeller is coupled to the shaft disposed within the
turbine impeller
chamber. A pump impeller is coupled to the shaft and disposed within the pump
impeller
chamber. The pump impeller comprises a rotating thrust face opposite the
stationary thrust face.
A land is disposed between the stationary thrust face and the rotating thrust
face. The center
bearing defines a distribution groove disposed at least partially around the
shaft. A feed supply
couples the pump outlet to the distribution groove. A thrust bearing comprises
a thrust bearing
cavity defined between the stationary thrust face, the rotating thrust face
and the land. The thrust
bearing receives filtered fluid from the pump outlet. A first bearing
clearance through the center
bearing fluidically couples the distribution groove to the thrust bearing
cavity. A second bearing
clearance through the center bearing fluidically couples the distribution
groove to the turbine
impeller chamber.
[0038] In another aspect of the disclosure, method of operating a
fluid machine
comprises communicating fluid from a pump outlet to a distribution groove
disposed in a center
bearing, communicating fluid from the distribution groove to a thrust bearing
formed between a
stationary end surface of a center bearing and an end surface of a pump shroud
that is coupled to
a shaft, rotating the shaft to generate a first axial force, and generating a
second axial force
CA 3056662 2019-09-25
counter to the first axial force in response to communicating fluid from the
distribution groove to
the thrust bearing.
[0039] In
another aspect of the invention, a fluid machine assembly includes a casing
comprising a pump portion having a pump impeller chamber, a pump inlet and a
pump outlet. A
pump impeller is disposed in the pump impeller chamber. The casing further
comprises a turbine
portion having a turbine inlet, a turbine outlet and a turbine impeller
chamber. A turbine
impeller is disposed in the turbine impeller chamber. The turbine impeller
comprises a turbine
shroud having a rotating thrust face. A shaft extends between the pump
impeller and the turbine
impeller. The shaft comprises a center axial shaft passage, a first radial
shaft passage and a
second radial shaft passage. A turbine wear ring is disposed around the
turbine outlet comprising
a stationary thrust face opposite the rotating thrust. A center bearing is
disposed around the shaft
between the pump impeller chamber and turbine impeller chamber. The center
bearing and the
shaft comprise a bearing clearance therebetween. A land is disposed between
the stationary
thrust face and the rotating thrust face. A thrust bearing comprising a thrust
bearing cavity
defined between the stationary thrust face, the rotating thrust face and the
land. The thrust
bearing receives filtered fluid from the pump outlet. A lubricant supply
couples lubricant to the
thrust bearing cavity. An impeller passage communicates lubricant from the
thrust bearing
cavity to the center axial shaft passage. The axial shaft passage communicates
lubricant to the
bearing clearance through the first radial shaft passage and the second radial
shaft passage. The
bearing clearance communicates lubricant to the pump impeller chamber and the
turbine impeller
chamber.
[0040] In
yet another aspect of the invention, a method includes communicating
lubricant to a thrust bearing cavity disposed between a turbine impeller and a
thrust wear ring,
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communicating lubricant from the thrust bearing cavity to a center axial shaft
passage of a shaft
through an impeller passage of the turbine impeller, communicating lubricant
through the axial
shaft passage to a bearing clearance between a shaft and a center bearing
through a first radial
shaft passage and a second radial shaft passage and communicating lubricant
through the bearing
clearance to a pump impeller chamber and a turbine impeller chamber.
[0041] Further areas of applicability will become apparent from the
description
provided herein. The description and specific examples in this summary are
intended for
purposes of illustration only and are not intended to limit the scope of the
present disclosure.
DRAWINGS
[0042] The drawings described herein are for illustration purposes
only and are not
intended to limit the scope of the present disclosure in any way.
[0043] FIG. 1 is a cross-sectional view of a first turbocharger
according to the prior
art.
[0044] FIG. 2 is a cross-sectional view of a first fluid machine
according to the prior
art.
[0045] FIG. 3 is an end view of an impeller of FIG 2.
[0046] FIG. 4 is a cross-sectional view of a second fluid machine
according to the
prior art.
[0047] FIG. 5 is a cross-sectional view of a third example of a
turbine portion
according to the prior art.
[0048] FIG. 6A is a cross-sectional view of a fourth example of a
turbine portion
according to the prior art.
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[0049] FIG. 6B is a cross-sectional view of an alternative example of an
impeller of
the prior art.
[0050] FIG. 7 is a cross-sectional view of a fifth example of a turbine
having an axial
lubrication system of the prior art.
[0051] FIG. 8A is a cross-sectional view of a first example according to
the present
disclosure.
[0052] FIG. 8B is a front view of the balance disk of FIG. 8A.
[0053] FIG. 8C is a cross-sectional view of the balance disk relative to a
bearing
surface of FIG. 8A.
[0054] FIG. 8D is a cross-sectional view of a second example according to
the
present disclosure.
[0055] FIG. 8E is a cross-sectional view of a third example according to
the present
disclosure
[0056] FIG. 9 is a fourth example of a hydraulic pressure booster according
to the
disclosure.
[0057] FIG. 10 is a fifth example of a hydraulic pressure booster according
to the
disclosure.
[0058] FIG 11 is a sixth example of a hydraulic pressure booster according
to the
disclosure.
[0059] FIG. 12A is an axial cross-sectional view of channel in a shaft
of first example
for use in FIG 11.
[0060] FIG 12B is a radial cross-sectional view of channel in a shaft
of first example
for use in FIG 11.
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[0061] FIG. 12C is an axial cross-sectional view of channel in a shaft
of second
example for use in FIG 11.
[0062] FIG 12D is a radial cross-sectional view of channel in a shaft
of second
example for use in FIG 11.
[0063] FIG. 12E is an axial cross-sectional view of channel in a shaft
of third
example for use in FIG 11.
[0064] FIG 12Fis a radial cross-sectional view of channel in a shaft
of third example
for use in FIG 11.
[0065] FIG. 12G is an axial cross-sectional view of channel in a shaft
of fourth
example for use in FIG 11.
[0066] FIG 12H is a radial cross-sectional view of channel in a shaft
of fourth
example for use in FIG 11.
DETAILED DESCRIPTION
[0067] The following description is merely exemplary in nature and is
not intended to
limit the present disclosure, application, or uses. For purposes of clarity,
the same reference
numbers will be used in the drawings to identify similar elements. As used
herein, the phrase at
least one of A, B, and C should be construed to mean a logical (A or B or C),
using a non-
exclusive logical OR. It should be understood that steps within a method may
be executed in
different order without altering the principles of the present disclosure.
[0068] In the following description, a hydraulic pressure booster
having a turbine
portion and pump portion is illustrated. However, the present disclosure
applies equally to other
fluid machines. The present disclosure provides a way to deliver pumpage to a
thrust bearing
over the operating range of the device. Debris entering the turbine is also
reduced.
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[0069] Referring now to Figure 8A, a fluid machine such as a hydraulic
pressure
booster 910 according to the present disclosure is set forth. In this example,
the components with
the same reference numerals described above in Figures 1-7 are set forth. In
this example, the
hydraulic pressure booster 910 includes a first bearing 912 and a second
bearing 914 that are
spaced apart. In this example, the bearing 912 may be referred to as a turbine
bearing and the
bearing 914 may be referred to as a pump bearing. The pump bearing 914 and
turbine bearing
912 define a balance disk chamber 916. The balance disk chamber 916 houses a
balance disk 918
which is rotatably coupled to the common shaft 20. The bearing 912 has a first
side 912A that is
disposed adjacent to the turbine impeller 40 and a second surface 912B within
the balance disk
chamber 916. The bearing 914 has a first side 914A adjacent to the pump
impeller 22 and a
second side 914B within the balance disk chamber 916. The bearings 912 and 914
provide radial
support for the shaft 920. The turbine outlet 44 is coaxial with the shaft 20.
[0070] The balance disk 918 has a first side or surface 918A that
faces surface 912B
and a second surface 918B that faces the second surface 914B. Surface 918A has
a land 930. The
second surface 918B has a second land 932. The lands 930 and 932 are annular
in shape. In an
alternate example, the land 930 may be disposed on the surface 912B. Land 932
may also be
disposed on the surface 914B.
[0071] A first thrust bearing 940 is defined by the volume between the
surface 912B,
surface 918A and the first land 930. A second thrust bearing 942 is defined
between the surface
914B, surface 918B and the land 932. The thrust bearing and the land 932. The
thrust bearings
940, 942 are provided with process fluid from either the turbine flow or the
feed flow as will be
defined below. Fluid is communicated to the first thrust bearing 940 through
an inlet port 944.
Fluid is communicated to the second thrust bearing 942 through a port 946. The
port 944 is in
CA 3056662 2019-09-25
fluid communication with a channel 948 that extends through the bearing 912
and the casing 26.
A channel 950 is in fluid communication with the port 946 through the bearing
914 and the
casing 26. Another channel 952 may extend through the casing 26 and provide
fluid adjacent to
the balance disk 918.
[0072] A first pipe 954 may communicate fluid to the first channel
948. A second
pipe 956 communicates processed fluid to the channel 950. Pipe 958
communicates fluid to the
channel 950.
[0073] Each of the pipes 954, 956 and 958 may be in communication with
a four-way
valve 960. The four-way valve 960 selectively communicates fluid to the pipes
954-956. It
should be noted that the four-way valve 960 may receive fluid from a filter
962. The filter 962
filters out contaminants from the process fluid before reaching the pipes 954-
958. Fluid from the
filter 962 is communicated through a pipe 964.
[0074] In operation, the four-way valve 960 may be eliminated if the
hydraulic
pressure booster 910 is used in one or selected operating conditions. That is,
the loads acting on
the shaft from the turbine impeller 40 or the pump impeller 22 may always act
in a constant
direction during operation. Thus, one of the channels 948-952 may be provided
in the design
while eliminating the others.
[0075] A three-way valve 970 is in communication with the turbine
inlet 42 and the
pump outlet 32 through pipes 972 and 974, respectively.
[0076] In operation, a counter thrust to balance the thrust of the
rotor is provided with
the balance disk 918 and the thrust bearings 940 and 942 associated therewith.
As mentioned
above, only one thrust bearing need be formed in certain design conditions.
When the thrust
indicated by arrow 50, which is toward the turbine portion, is present,
lubrication flow may be
16
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admitted through the pipe 954 and into the channel 948 where it enters to form
a thrust bearing
through the port 944. Fluid enters the pipe through the four-way valve 960,
the pipe 958 and the
filter 962. Fluid may be communicated into the filter 962 through the three-
way valve 970 which
operates to provide fluid from either the turbine inlet 42 or the pump outlet
32. The three-way
valve 970 may be controlled by a controller 980 which may be microprocessor-
based. The
controller 980 may also control the operation of the four-way valve 960.
[0077] If the thrust is directed toward the pump side of the HPB 910,
lubrication flow
may be admitted through channel 950 and pipe 956. Fluid is communicated
through the four-way
valve 960, the three-way valve 970 and from one of the turbine inlet 42 or the
pump outlet 32.
[0078] As briefly mentioned above, it may also be desirable to
communicate fluid
simultaneously through the pipes 954 and 958. Likewise, it may be desirable to
communicate
fluid through pipes 956 and 958. The pipe 958 communicates fluid to the
channel 952. The
channel 952 provides fluid adjacent to the peripheral edge of the balance disk
918.
[0079] Referring now to Figure 8B, to increase the thrust force,
hydrodynamic action
of the balance disk 918 may be used. The balance disk 918 may be provided with
a plurality of
radially oriented surface recesses that generate hydrodynamic lift that
increases in strength as the
gap between the balance disk and the adjacent bearing face decreases. In this
example, a first
plurality of recesses 982A extends from the outer periphery of the balance
disk 918 to just short
of a groove 984. The groove 984 is a reduced thickness portion. It should be
noted that each
surface 918A, 918B of the balance disk may include such surfaces. However,
only one surface in
various designs may be used. The recesses 982B extend from the groove 984 to
just short of the
outer periphery of the balance disk 918. The recesses 982A and 982B are
interspersed. That is,
17
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when traversing around the balance disk 918, the recesses 982A alternate with
recesses 982B. In
this example, there are four recesses 982A and four recesses 982B.
[0080] Referring now to Figure 8C, a cross-sectional view of the
balance disk relative
to one of the surfaces 912B or 914B is set forth. In this example, the balance
disk is moving in
the direction indicated by the arrow 986. Each of the recesses 982A or 982B
may be formed
according to the following. The recesses 982A or 982B include a tapered
portion 988. The
groove 990 is on the leading edge and thus pressure is built up in the tapered
portion 988 due to
the movement of the balance disk 918 in the direction indicated by the arrow
986.
[0081] Because the lubrication flow to the thrust bearings are
filtered, the clearance
between the surfaces 912B or 914B and the balance disk 918 may be small. The
clearance is
smaller than the distance between the wear rings 232.
[0082] Referring now to Figure 8D, the balance disk 918 includes a
flow channel 992
therethrough. The flow channel 992 extends within the balance disk 918 and
communicates fluid
from a first side of the balance disk to a second side of the balance disk
918. In Figure 8D, fluid
is communicated from the pump side or surface 918B of the balance disk 918 to
the turbine side
or surface 918A of the balance disk 918.
[0083] The flow channel 992 has a first axial portion 992A that
extends from the
pump side 918B proximate to or adjacent to the shaft 20. A radial portion 992B
extends in a
radial direction from the first axial portion 992A. The radial portion 992B
extends away from the
shaft 20 in a radial direction. A second axial portion 992C couples the radial
portion 992B to the
second side of the balance disk 918.
[0084] In operation, fluid flows from the first side or surface 918A
of the balance
disk 918 which corresponds to the pump side through the first axial portion
992A, through the
18
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radial portion 992B where the centrifugal forces cause an increase in the
pressure of the fluid.
The centrifugal force is caused by the high rate of rotation of the shaft 20
and the rotor associated
therewith. Fluid exits to the second surface 918B of the balance disk 918
through the second
axial portion 992C into the thrust bearing formed on the first surface 918A.
The second axial
portion 992C is located a further distance from the shaft 20 than the first
axial portion 992A
(radially outward). The flow channel 992 consequently increases the capacity
of the thrust
bearing at the turbine side of the balance disk 918.
[0085] It should be noted that a plurality of flow channels may be
included in the
balance disk. To provide balanced forces, the flow channels may be
symmetrically disposed
about the balance disk 918. It should also be noted that in Figure 8D, the
thrust forces that act on
the shaft are in the direction toward the turbine side.
[0086] Referring now to Figure 8E, another embodiment of a flow
channel within a
balance disk 918 is set forth in a similar manner as that of Figure 8D.
However, in Figure 8E, the
predominant forces are in the direction of the pump portion 16. Therefore, a
flow channel 994 is
communicating fluid from the first surface 918A of the balance disk which
corresponds to the
turbine portion to the second surface 918B of the balance disk which
corresponds to the pump
side of the balance disk 918. In this example, the flow channel 994 includes a
first axial portion
994A that is fluidically coupled to the first surface 918A of the balance disk
918. A radial
portion 9948 communicates fluid from the first axial portion 994A to a second
axial portion
994C. The second axial portion 994C communicates fluid to the second surface
918B of the
balance disk. In a similar manner to that described above with respect to
Figure 8D, fluid enters
the first axial portion 994A adjacent to or proximate to the shaft 20. The
pressure of the fluid
within the flow channel 994 is increased by the centrifugal forces acting on
the rotating balance
19
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disk 918. The fluid pressure increases within the radial portion 994B as the
fluid traverses in the
direction illustrated by the arrow toward the outward direction of the balance
disk 918 away
from the shaft 20. Higher pressure fluid then enters the thrust bearing
located at the pump side of
the balance disk 918. As mentioned above, the increased high pressure fluid
into the thrust
bearing increases the capacity of the thrust bearing, in this case, on the
pump side of the
hydraulic pressure booster 910.
[0087] Referring now to Figure 9, an alternative fluid machine 1010 is
set forth. hi
this example, fluid is communicated from the pump outlet 32 to the filter 1011
disposed within a
pipe 1012. A pipe 1014 may communicate fluid from the pump outlet to the shaft
20 between the
turbine portion 18 and the pump portion 16 of the fluid machine 1010 such as a
hydraulic
pressure booster. In this example, the balance disk 1030 and balance disk
chamber 1042 have
been relocated outboard and adjacent to the turbine portion 18 of the fluid
machine. The casing
26 may be supplemented with a casing extension or outer cap 1020 that is
fastened with a bolt
1022 to a turbine end of the casing 26. The casing 26 and the outer cap 1020
may have a hollow
space therebetween to house a first bearing 1024 and a second bearing 1026.
The bearings 1024
and the bearings 1026 have inner surfaces 1024A and 1026A, respectively. The
surface 1024A
may form thrust bearing 1040 between surfaces 1030A of the balance disk 1030
within the
volume defined by the wear ring 1080 disposed on the surface 1030A.
[0088] The flow channels 992, 994 illustrated in the balance disks
illustrated in
Figures 8D and 8E may also be incorporated within the balance disk 1030 to
increase the
capacity of the thrust bearings 1040.
[0089] A shaft extension 1032 may extend from the turbine portion 18
and the shaft
20 so that the balance disk 1030 and the wear ring 1080 rotates therewith. A
shaft seal 1034 seals
CA 3056662 2019-09-25
the shaft extension 1032 from leakage with the turbine outlet 44. The turbine
outlet 44 is
perpendicular to the shaft 20.
[0090] The pipe 1014 and the channel 1014A are provided closer to the
pump
impeller 22 than the turbine impeller 40. That is, the distance between the
pump impeller 22 and
the channel 1014A is less than the distance between the channel 1014A and the
turbine impeller
40.
[0091] In operation, the rate of flow to the thrust bearing 1040
formed by a volume
within the balance disk chamber 1042 between the outer cap 1020 of the bearing
casing, the
balance disk 1030 and wear ring 1080 is very low since the only passage into
the thrust bearing
volume is through the shaft seal 1034.
[0092] A temperature sensor 1044 and a proximity sensor 1046 may be
disposed
within the bearing 1024 to generate a temperature signal corresponding to a
temperature at the
bearing 1024 and a proximity signal of the balance disk 1030 relative distance
to the bearing
1024. The output of the temperature sensor 1044 may be used to control the
heat exchanger 1050
and thus cool the fluid within the thrust bearing 1040. The fluid from the
thrust bearing 1040
may be communicated through the heat exchanger 1050 and to the inlet pipe 1052
in a cooled
state. The circulation through the heat exchanger 1050 is driven by the higher
pressure caused by
the rotating balance disk 1030. That is, a higher pressure exists at the outer
diameter of the
balance disk 1030 and thus the fluid may be communicated through the heat
exchanger and back
through the inlet pipe 1052.
[0093] The speed sensor 1060 may be used to monitor the rotational
speed of the
shaft extension 1032 which also corresponds to the rotational speed of the
shaft 20. The speed
sensor 1060 may be located within the turbine outlet 44 or adjacent to the
temperature sensor
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1044 and the proximity sensor 1046. A tooth or other indicator on the balance
disk may provide
the sensor with the rotational speed of the shaft.
[0094] Referring now to Figure 10, another example of a hydraulic
pressure
booster 1100 is set forth. The same components from the above examples use the
same
reference numerals. In the following example, the balance disk is eliminated.
In this example, a
thrust bearing 1120 is formed within the pump cavity 1122. The pump cavity
1122 also includes
a volute 1124. The casing 26 has a center bearing 1130 disposed therein. The
center bearing
1130 extends between the pump portion 16 and the turbine portion 18. The
center bearing 1130
has an end surface that forms a stationary thrust face 1132. The shaft 20
extends through and is
normal to the thrust face extends around the shaft 20.
[0095] The pump impeller 22 has a shroud 1136 that is generally
cylindrical in
shape and has an end surface 1138. The end surface 1138 of the shroud 1136
rotates together
with the shaft 20. In this example, a land 1140 is disposed on the end surface
1138 of the shroud
1136. The land 1140 thus rotates with the shroud 1136 and the pump impeller
22. Of course, the
land 1140 may be disposed on the center bearing 1130 and in particular the end
surface (thrust
face 1132) of the center bearing 1130. As illustrated, the gap or distance
between the end of the
land 1140 and the stationary thrust face 1132 of the center bearing 1130 is
Di. As will be further
described below, various operating conditions may cause the gap Di to vary.
[0096] A thrust bearing cavity 1142 of the thrust bearing 1120 is
defined between
the end surface 1138, the stationary thrust face 1132, the land 1140 and the
shaft 20. Ultimately,
clean fluid from the pump outlet 32 is communicated to the thrust bearing
cavity 1142.
[0097] A feed supply 1144 fluidically communicates fluid from the
pump outlet
32 to the thrust bearing cavity 1142. The feed supply 1144 includes a pipe
1146 that has a filter
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1148 disposed therein. The filter 1148 is used to filter the possibly
contaminated outlet fluid of
the pump outlet 32. The pipe 1146 is coupled to a channel 1150 that extends
through the casing
26. A second channel 1152 through the center bearing 1130 is in fluid
communication with the
channel 1150 and the pipe 1146. The channels 1150 and 1152 extend in a radial
direction toward
the shaft 20 and are part of the feed supply 1144.
[0098] The center bearing 1130 includes a distribution groove 1160
disposed
around the longitudinal axis of the center bearing 1130 and hydraulic pressure
booster 1100. The
groove 1160 has a width WI and a depth Ri that corresponds to the distance
from the shaft 20.
The distribution groove 1160 is ring shaped and is around the shaft 20.
[0099] The distribution groove 1160 is fluidically coupled to both
the pump
portion 16 and the turbine portion 18internal to the casing 26. More
specifically, the distribution
groove 1160 is in fluid communication with the thrust bearing cavity 1142
through a first bearing
clearance 1162 in center bearing 1130. A second bearing clearance 1164 in the
center bearing
fluidically communicates fluid from the distribution groove 1160 to the
turbine cavity 1166. The
first bearing clearance 1162 and the second bearing clearance 1164 extend in
an axial direction.
In this example, the distribution groove 1160 is closer to the pump portion
than the turbine
portion. That is, the length of the first bearing clearance 1162 is less than
the length of the
second bearing clearance 1164.
[0100] In operation, a portion of the high pressure fluid that
exits the pump outlet
32 is partially communicated through the pipe 1146 and through the filter 1148
of the feed
supply 1144. Fluid from the pipe 1146 is communicated through the channels
1150 and 1152 of
the feed supply 1144 into the distribution groove 1160. The fluid from the
distribution groove
1160 is communicated both to the pump portion 16 and the turbine portion 18.
In particular,
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fluid from the distribution groove 1160 is communicated through the first
bearing clearance 1162
into the thrust bearing cavity 1142.
Fluid from the distribution groove 1160 is also
simultaneously communicated through the second bearing clearance 1164 and into
the turbine
cavity 1166. Fluid flowing through the bearing clearances 1162, 1164 provide
lubrication and
cooling to the center bearing 1130. Fluid entering the thrust bearing cavity
1142 is
communicated through the distance Di between the end of the land 1140 and the
stationary thrust
face 1132 of the center bearing 1130.
[0101] The
pressure within the thrust bearing cavity 1142 counteracts the natural
force of the hydraulic pressure booster indicated by arrow 1168. When the gap
Di increases, the
pressure within the thrust bearing cavity 1142 is reduced and thus the land
1140 moves closer to
the center bearing 1130. When the pressure within the thrust bearing cavity
1142 increases the
gap DI and thus the pressure within the thrust bearing 1142 is reduced. Thus,
movement of the
pump impeller 22 and the land 1140 connected thereto restricts or increases
the fluid flow
between the land 1140 and the stationary thrust face 1132 of the center
bearing 1130. In should
be noted that the thrust bearing 1120 provides a counter thrust or force to
the force indicated buy
the arrow 1168. The flow of fluid from the thrust bearing cavity 1142
ultimately is
communicated to the pump of volute 1124.
[0102] As
mentioned above, in one constructed example the axial length of the
first bearing clearance 1162 is less than the length of the second bearing
clearance 1164. The
length of the first bearing clearance 1162 and the second bearing clearance
1164 are related to
the axial location of the distribution groove 1160. A shorter first bearing
clearance 1162 results
in the pressure within the thrust bearing cavity 1142 being higher. The
"stiffness" of the thrust
24
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bearing 1120 increases with a longer first bearing clearance 1162. This is
because the change in
flow will result in a larger pressure change through the first bearing
clearance 1162.
[0103] The volume of the distribution groove 1160 is defined
between the shaft
20, the width WI and the depth Di. The depth Di is terminated by the
longitudinally extending
wall 1170. The longitudinal width WI of the distribution groove 1160 is
defined by the lateral
walls 1178 and 1180. The volume of the distribution groove 1160 may be changed
based upon
various design and use considerations. The amount of flow between the land
1140 and the
stationary thrust face 1132 of the center bearing 1130 is considered when
sizing the distribution
groove 1160. The flow of fluid between the land 1140 and the stationary thrust
face 1132
changes based on axial movement of the shaft 20 and the pump impeller 22. The
amount of flow
through the gap Di in extreme operating conditions is compensated for by the
amount of volume
within the distribution groove 1160. That is, the amount of volume within the
distribution
groove 1160 may be sized to compensate for a rapid flow of fluid through the
gap Di. The
volume of the distribution groove 1160 is capable of replacing rapidly lost
volume within the
thrust bearing cavity 1142. The volume within the distribution groove 1160 is
thus a function of
the thrust bearing cavity volume.
[0104] Another design consideration is the amount of volume within
the thrust
bearing cavity 1142. As the radial distance between the land 1140 and the
shaft 20 increases, a
greater amount of thrust may be accommodated.
[0105] Referring now to FIG 11, ultra-high pressure applications
such as those
involving hazardous fluids require a large flange between the pump and turbine
impellers and
thus long shafts are required to be used. Long shafts have reduced stiffness
and require
additional bearing area for support. This results in greater drag and a
potential for rubbing. In
CA 3056662 2019-09-25
this example, a hydraulic pressure booster 1200 has the thrust bearing 28 that
receives fluid from
the lubricant passage 740. In this example, the lubricant passage 740 extends
in an axial
direction through the casing 26. A pipe 742 fluidically communicates lubricant
from a filter 744
to the lubricant passage 740. The filter removes particulates to protect the
bearing surfaces from
wear.
[0106] A check valve 746 disposed in a pipe 748 that fluidically
communicates a
lubrication source 750 with the filter 744 is set forth. The check valve 746
allows flow from the
lubrication source 750 to reach the filter 744 but prevents flow in the
opposite direction. That is,
flow from the hydraulic pressure booster 1200 is prevented from leaving the
thrust bearing cavity
729.
[0107] In the example set forth in FIG. 11, lubricant flows in the
opposite
direction as that illustrated in FIG 7. The thrust bearing 728 is formed in a
similar manner to that
illustrated above with respect to FIG. 7 in that a thrust bearing 728 has a
thrust bearing cavity
729 defined by the rotating thrust face 730, the stationary thrust face 732,
the inner land 736 and
the outer land 738. Lubricant flows from a lubrication source 750 through the
lubricant passage
740 into the thrust bearing cavity 729. The lubricant passage 740 extends
through an axial end
741 of the casing 26 at the axial end 741. As denoted in described lines, the
lubricant source 750
may be the pump outlet 32 which may be filtered by filter 744. Lubricant flows
from the thrust
bearing cavity 729 into the axially extending passages 726 that are disposed
within the vanes
724. Lubricant flows from the axially extending passages to the radially
extending passages 720.
Lubricant flows from the radially extending passages 720 to the center axial
shaft passage 710
disposed within the shaft 20v. Fluid flows from the central axial shaft
passage 710 of the shaft
20" to a first radial shaft passage 762 and a second radial shaft passage 764.
In this example, the
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first radial shaft passage 762 and the second radial shaft passage 764 are
perpendicular to the
center axial shaft passage 710.
[0108] A bearing clearance 760 is disposed between the center
bearing 24 and the
shaft 20Iv. The bearing clearance 760 received fluid from both the first
radial shaft passage 762
and the second radial shaft passage 764. The lubricant flows in an axial
direction toward the
pump impeller chamber 23 and the turbine impeller chamber 41. The lubricant
prevents rubbing
of the shaft with the center bearing 24 as well as provides cooling.
[0109] It should be noted that the location of the axially
extending passages 726
are located close to the longitudinal axis LA of the hydraulic pressure
booster 1200. This
reduces the adverse centrifugal pressure gradient exerted in the radially
extending passages 720.
[0110] One advantage of the system is that during start up and shut
down, the
pressure of lubrication flow passing through the inlet pipe 42 of the turbine
portion 18 may be
insufficient for lubricated the rotor. The check valve 746 prevents lubricant
fluid from leaving
the casing and the thrust bearing cavity 729. This prevents contaminated fluid
from entering the
bearing cavity 729 from the turbine impeller chamber 41. In normal start up,
the rotor 43 comes
up to speed in a matter of a few seconds and thus the prevention of backflow
or reverse flow
through the lubricant passage 740 avoids damage until normal lubrication flow
is established.
[0111] Referring now to FIGS. 12A and 12B, the shaft 20vI is
illustrated in
further detail. In this example, the first radial shaft passage 762 and the
second radial shaft
passage 764 are illustrated in further detail. The example set forth in FIGS.
12A and 12B are
suitable for many conditions. However, because the first radial shaft passage
762 and the second
radial shaft passage 764 are disposed in the same cross-sectional plane, a
weakening of the shaft
27
CA 3056662 2019-09-25
might take place. That is, the first radial shaft passage 762 and the second
radial shaft passage
764 intersect the center axial shaft passage at point P.
[0112] Referring now to FIGS. 12C and 12D, the first radial shaft
passage 762'
and the second radial shaft passage 764' intersect the central axial shaft
passage at different
locations. That is, the intersection of the center axial shaft passage 710 and
the intersections P1
and P2 the first radial shaft passage 762' is P2 and the second radial shaft
passage 764' is P2 are
offset in a longitudinal direction to increase the strength of the rotating
shaft 20V11
[0113] Referring now to FIGS. 12E and 12F, the first radial shaft
passage 762"
and the second radial shaft passage 764" are disposed in an angular direction
relative to the
longitudinal axis LA of the shaft 20v11. In this example, the angle A relative
to the longitudinal
axis LA of the shaft 20 is about 45 degrees. In this example, the center axial
shaft passage 710
and the first radial passage shaft passage 762" and the second radial shaft
passage 764" intersect
at a common point P3.
[0114] Referring now to FIGS. 12G and 12H, the intersection of the
center axial
shaft passage 710 and the first radial shaft passage 762" is P4 and the second
radial shaft
passage 764" is P5. The intersection points P4 and P5 are offset in a
longitudinal direction.
This is believed to increase the strength of the shaft 20Iv.
[0115] In FIGS. 12E-12H a 45 degree angle is illustrated. However,
various
angles between about 30 and about 60 degrees relative to the longitudinal axis
LA of the shaft
20vin may be provided. It is believed that the shaft 2O" illustrated in FIG.
12G provides the
strongest shaft arrangement because two angled channels are axially staggered
to eliminate
overlap in any radial plane. The intersection of the radial shaft passages
762, 764 with the control
axial shaft 760 are off set at points P4 and P5.
28
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[0116]
Those skilled in the art can now appreciate from the foregoing description
that the broad teachings of the disclosure can be implemented in a variety of
forms. Therefore,
while this disclosure includes particular examples, the true scope of the
disclosure should not be
so limited since other modifications will become apparent to the skilled
practitioner upon a study
of the drawings, the specification and the following claims.
29
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