U.S. patent application number 16/040487 was filed with the patent office on 2019-01-24 for pumping system shaft conversion adapter.
This patent application is currently assigned to GE Oil & Gas ESP, Inc.. The applicant listed for this patent is GE Oil & Gas ESP, Inc.. Invention is credited to Joseph Ashurst, Blair Ellington, Andrew Roberts, Matthew Schoelen.
Application Number | 20190024665 16/040487 |
Document ID | / |
Family ID | 65015608 |
Filed Date | 2019-01-24 |
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United States Patent
Application |
20190024665 |
Kind Code |
A1 |
Ashurst; Joseph ; et
al. |
January 24, 2019 |
Pumping System Shaft Conversion Adapter
Abstract
A pump for use in a motorized pumping system has a pump shaft
with a lower ring groove and an upper ring groove. The pump also
includes a lower adapter and an upper adapter. The lower adapter
has a pair of lower ring halves configured to fit within the lower
ring groove and the upper adapter has a pair of upper ring halves
configured to fit within the upper ring groove. The pump further
includes a plurality of stages that each have a stationary diffuser
and a rotating impeller. The rotating impellers are connected to
the shaft with a keyed connection that permits the impeller to
axially travel along the shaft. Also disclosed is a method for
converting a compression shaft to a floater shaft that includes the
steps of placing an upper adapter into the upper ring groove,
placing one or more impellers on the shaft, placing one or more
standard spacers on the shaft and placing a lower adapter into the
lower ring groove.
Inventors: |
Ashurst; Joseph; (Oklahoma
City, OK) ; Roberts; Andrew; (Jacksonville, FL)
; Ellington; Blair; (Oklahoma City, OK) ;
Schoelen; Matthew; (Norman, OK) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
GE Oil & Gas ESP, Inc. |
Oklahoma City |
OK |
US |
|
|
Assignee: |
GE Oil & Gas ESP, Inc.
Oklahoma City
OK
|
Family ID: |
65015608 |
Appl. No.: |
16/040487 |
Filed: |
July 19, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62535224 |
Jul 20, 2017 |
|
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|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F04D 29/054 20130101;
F04D 29/042 20130101; F04D 29/628 20130101; F04D 1/063 20130101;
F04D 1/06 20130101; F04D 29/047 20130101; E21B 43/128 20130101;
F04D 13/10 20130101 |
International
Class: |
F04D 13/10 20060101
F04D013/10; F04D 1/06 20060101 F04D001/06; F04D 29/054 20060101
F04D029/054 |
Claims
1. A pump for use in a motorized pumping system, the pump
comprising: a shaft, wherein the shaft includes a lower ring groove
and an upper ring groove; a lower adapter, wherein the lower
adapter comprises a pair of lower ring halves configured to fit
within the lower ring groove; an upper adapter, wherein the upper
adapter comprises a pair of upper ring halves configured to fit
within the upper ring groove; a plurality of stages, wherein each
of the plurality of stages comprises: a stationary diffuser; and a
rotating impeller connected to the shaft with a keyed connection
that permits the impeller to axially travel along the shaft.
2. The pump of claim 1, wherein the lower adapter further comprises
a lower adapter snap ring configured to hold the pair of lower ring
halves together in the lower ring groove.
3. The pump of claim 1, wherein the upper adapter further comprises
an upper adapter snap ring configured to hold the pair of upper
ring halves together in the upper ring groove.
4. The pump of claim 1, wherein the lower adapter comprises a lower
adapter shoulder that has an adapter shoulder outer diameter.
5. The pump of claim 4, further comprising a lower bearing that has
an inner diameter that is larger than the adapter shoulder outer
diameter.
6. The pump of claim 5, wherein the lower bearing support comprises
a bearing pad.
7. The pump of claim 6, further comprising a bearing spacer
connected to the shaft and configured to contact the bearing pad of
the lower bearing support.
8. A submersible pumping system comprising: an electric motor; a
seal section; and a multistage centrifugal pump driven by the
motor, wherein the pump comprises: a shaft, wherein the shaft
includes a lower ring groove and an upper ring groove; a lower
adapter, wherein the lower adapter comprises a pair of lower ring
halves configured to fit within the lower ring groove; an upper
adapter, wherein the upper adapter comprises a pair of upper ring
halves configured to fit within the upper ring groove; and a
plurality of stages, wherein each of the plurality of stages
comprises: a stationary diffuser; and a rotating impeller connected
to the shaft with a keyed connection that permits the impeller to
axially travel along the shaft.
9. The submersible pumping system of claim 8, wherein the lower
adapter further comprises a lower adapter snap ring configured to
hold the pair of lower ring halves together in the lower ring
groove.
10. The submersible pumping system of claim 8, wherein the upper
adapter further comprises an upper adapter snap ring configured to
hold the pair of upper ring halves together in the upper ring
groove.
11. The submersible pumping system of claim 8, wherein the lower
adapter comprises a lower adapter shoulder that has an adapter
shoulder outer diameter.
12. The submersible pumping system of claim 11, further comprising
a lower bearing that has an inner diameter that is larger than the
adapter shoulder outer diameter.
13. The submersible pumping system of claim 12, wherein the lower
bearing support comprises a bearing pad.
14. The submersible pumping system of claim 13, further comprising
a bearing spacer connected to the shaft and configured to contact
the bearing pad of the lower bearing support.
15. The submersible pumping system of claim 8, wherein the shaft
does not include any ring grooves other than the lower ring groove
and the upper ring groove
16. A method for converting a compression shaft to a floater shaft,
wherein the compression shaft includes an upper ring groove and a
lower ring groove that are respectively capable of holding an upper
two-piece ring and a lower two-piece ring to apply compression to a
diffuser stack disposed along the compression shaft, the method
comprising the steps of: placing an upper adapter into the upper
ring groove; placing one or more impellers on the shaft; placing
one or more standard spacers on the shaft; and placing a lower
adapter into the lower ring groove.
17. The method of claim 16, further comprising the step of placing
one or more bearing spacers on the shaft before the step of placing
a lower adapter into the lower ring groove.
18. The method of claim 16, wherein the step of placing an upper
adapter into the upper ring groove further comprises: placing a
first upper ring half into the upper ring groove; placing a second
upper ring half into the upper ring groove; and securing the first
and second upper ring halves together.
19. The method of claim 18, wherein the step of securing the first
and second upper ring halves together further comprises placing an
upper adapter snap ring over the first and second upper ring
halves.
20. The method of claim 16, wherein the step of placing a lower
adapter into the lower ring groove further comprises: placing a
first lower ring half into the lower ring groove; placing a second
lower ring half into the lower ring groove; and securing the first
and second lower ring halves together.
Description
RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Patent Application Ser. No. 62/535,224 filed Jul. 20, 2017 entitled
"Pumping System Shaft Conversion Adapter," the disclosure of which
is herein incorporated by reference.
FIELD OF THE INVENTION
[0002] This invention relates generally to the field of submersible
pumping systems, and more particularly, but not by way of
limitation, to a mechanism for converting shafts used in multistage
centrifugal pumps.
BACKGROUND
[0003] Multistage centrifugal pumps are used in a variety of
submersible and surface-based applications. In these pumps, each
"stage" includes a rotating impeller and a stationary diffuser. A
shaft keyed only to the impellers transfers mechanical energy from
the motor. During use, the rotating impeller imparts kinetic energy
to the fluid. A portion of the kinetic energy is converted to
pressure as the fluid passes through the downstream diffuser. As
the fluid is pressurized and moved through the pump, force pushes
against the impellers in the opposite direction. This force is
generally referred to as "down thrust." "Up-thrust" occurs as fluid
moving through the impeller pushes the impeller upward. Centrifugal
pumps have a flow rate equilibrium point where the up thrust and
down thrust generated by the impellers are balanced. Lower flow
rates cause excess down thrust, while higher flow rates may cause
excess up thrust. To prevent damage to the pump, the up thrust and
down thrust must be controlled using one or more thrust
bearings.
[0004] In many multistage pumps, the impellers are placed onto the
pump shaft and compressed between a pair of two-piece rings located
at opposite ends of the pump shaft. This design is often referred
to as a "fixed impeller" pump and the thrust generated by the
collection of impellers is transferred to the "compression shaft"
through the lower two-piece ring. The thrust is carried by the
compression shaft into a large thrust bearing that is often located
in a seal section that is adjacent to the pump.
[0005] In some cases, it is desirable to use a "floating impeller"
design in which the impellers are not all linked together under
compression. In a floating impeller design, the impellers are
allowed to move in an axial direction along the shaft during
operation and the down thrust generated by the impellers is not
transferred through the shaft to a dedicated thrust bearing.
Instead, the down thrust created by the impellers is offset by
"bearing stages" positioned at intervals within the pump. The
impellers must be free to move independently between bearing stages
to transfer the thrust to the bearing stages.
[0006] A standard "floater" shaft utilizes snap rings to hold the
impellers, spacers and other components to the shaft and allow for
free axial movement of the impellers. Existing floater shafts thus
include specific grooves at specified locations on the shaft to
accommodate the snap rings. These grooves are not typically present
on a compression shaft. Efforts to retrofit compression shafts to
accommodate a floating impeller design are expensive and time
consuming because the snap ring grooves must be added to the
compression shaft. There is, therefore, a need to develop an
adapter system that permits the facilitated conversion of a
compression shaft into a floater shaft. It is to these and other
objects that the present invention is directed.
SUMMARY OF THE INVENTION
[0007] In one aspect, embodiments of the present invention include
a pump for use in a motorized pumping system. The pump includes a
shaft that has a lower ring groove and an upper ring groove. The
pump also includes a lower adapter and an upper adapter. The lower
adapter has a pair of lower ring halves configured to fit within
the lower ring groove and the upper adapter has a pair of upper
ring halves configured to fit within the upper ring groove. The
pump further includes a plurality of stages that each have a
stationary diffuser and a rotating impeller. The rotating impellers
are connected to the shaft with a keyed connection that permits the
impeller to axially travel along the shaft.
[0008] In another aspect, an embodiment of the invention includes a
method for converting a compression shaft to a floater shaft, where
the compression shaft includes an upper ring groove and a lower
ring groove that are respectively capable of holding an upper
two-piece ring and a lower two-piece ring to apply compression to
an impeller stack disposed along the compression shaft. The method
includes the steps of placing an upper adapter into the upper ring
groove, placing one or more impellers on the shaft, placing one or
more standard spacers on the shaft and placing a lower adapter into
the lower ring groove.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 is an elevational view of a submersible pumping
system.
[0010] FIG. 2 is a cross-sectional view of the pump from the
submersible pumping system of FIG. 1.
[0011] FIG. 3 is a close-up, cross-sectional view of several stages
from the pump of FIG. 2.
[0012] FIG. 4 is a close-up, perspective, cross-sectional view of
the upper adapter near the head of the pump.
[0013] FIG. 5 is a cross-sectional view of the head of the pump
with upper adapter.
[0014] FIG. 6 is a close-up, perspective, cross-sectional view of
the lower adapter in the base of the pump.
[0015] FIG. 7 is a cross-sectional view of the base of the pump
with the lower adapter.
[0016] FIG. 8 is a close-up, cross-sectional view of the upper
adapter.
[0017] FIG. 9 is a close-up, cross-sectional view of the lower
adapter.
[0018] FIG. 10 is a perspective view of the lower adapter.
WRITTEN DESCRIPTION
[0019] FIG. 1 shows an elevational view of a pumping system 100
attached to production tubing 102. The pumping system 100 and
production tubing 102 are disposed in a wellbore 104, which is
drilled for the production of a fluid such as water or petroleum.
As used herein, the term "petroleum" refers broadly to all mineral
hydrocarbons, such as crude oil, gas and combinations of oil and
gas. The production tubing 102 connects the pumping system 100 to a
wellhead 106 located on the surface. Although the pumping system
100 is primarily designed to pump petroleum products, it will be
understood that the present invention can also be used to move
other fluids. It will also be understood that, although each of the
components of the pumping system are primarily disclosed in a
submersible application, some or all of these components can also
be used in surface pumping operations.
[0020] It will be noted that although the pumping system 100 is
depicted in a vertical deployment in FIG. 1, the pumping system 100
can also be used in non-vertical applications, including in
horizontal and non-vertical wellbores 104. Accordingly, references
to "upper" and "lower" within this disclosure are merely used to
describe the relative positions of components within the pumping
system 100 and should not be construed as an indication that the
pumping system 100 must be deployed in a vertical orientation.
[0021] The pumping system 100 includes a pump 108, a motor 110 and
a seal section 112. In some embodiments, the motor 110 is an
electrical motor that receives power from a surface-mounted motor
control unit (not shown). When energized, the motor 110 drives a
shaft that causes the pump 108 to operate. The seal section 112
provides for the expansion of motor lubricants during operation
while isolating the motor 110 from the wellbore fluids passing
through the pump 108. Although only one of each component is shown,
it will be understood that more can be connected when appropriate.
It may be desirable to use tandem-motor combinations, multiple seal
sections, multiple pump assemblies or other downhole components not
shown in FIG. 1. For example, in certain applications it may be
desirable to place a seal section 112 below the motor 110.
[0022] Turning to FIG. 2, shown therein is a cross-sectional view
of the pump 108. The pump 108 includes a pump housing 114, a head
116, a base 118, a shaft 120, and a plurality of stages 122. As
shown in the close-up view of FIG. 3, each of the plurality of
stages 122 includes a diffuser 124 and an impeller 126. The
impellers 126 are connected to the shaft 120 with a keyed
connection that permits axial movement of the impeller 126 along
the shaft 120. In this way, the impellers 126 are permitted a
limited amount of axial "float" between adjacent diffusers 124.
[0023] As illustrated in FIG. 3, the stages 122 in the pump 108 are
configured as either floating stages 128 or bearing stages 130. In
each floating stage 128, the impeller 126 transfers hydraulic load
to the lower or upstream impeller 126 through a standard spacer 132
that passes through the diffuser 124 without interference or
contact. In each bearing stage 130, the impeller 126 transfers down
thrust through a spacer 132 to a bearing spacer 136 by contact with
a bearing pad 134 in the adjacent diffuser 124. In this way, the
hydraulic load created by a collection of impellers 126 is
transferred into a diffuser 124 in a bearing stage 130. It will be
appreciated that some or all of the stages 122 can be configured as
a bearing stage 130. As illustrated in FIGS. 2, 6, and 7, the pump
108 may also include a separate lower bearing support 138 that
includes a bearing pad 134 that offsets thrust carried through a
bearing spacer 136.
[0024] Turning to FIGS. 4 and 5, shown therein are close-up,
cross-sectional views of a portion of the upper end of the pump
108. The shaft 120 includes a standard upper ring groove 140 that
is configured to accept a conventional two-piece ring (not shown),
which would be used in a fixed impeller pump to capture the
compression within the impeller stack. The two-piece ring has been
replaced with an upper adapter 142 for the floating impeller design
of the pump 108. A close-up, cross-sectional view of upper adapter
142 is shown in FIG. 8. The upper adapter 142 includes two upper
ring halves 144a, 144b. Each of the two upper ring halves 144a,
144b has a width that is configured to fit tightly within the upper
ring groove 140. Each of the upper ring halves 144a, 144b further
includes an upper adapter snap ring groove 146 and an upper adapter
shoulder 148.
[0025] During assembly, the two upper ring halves 144a, 144b are
placed into the upper ring groove 140 and approximated. An upper
adapter snap ring 150 can then be placed into the upper adapter
snap ring groove 146 to hold the two upper ring halves 144a, 144b
together within the upper ring groove 140. In other embodiments,
set screws or clamps are used to hold the two upper ring halves
144a, 144b together. Once assembled, the upper adapter 142 remains
fixed with the shaft 120 to contain and position the standard
spacers 132 and impellers 126 as they are allowed to move axially
along the shaft 120. The upper adapter 142 provides a stop and
upper limit for the upward, downstream displacement of the top
impeller 126 and spacers 132.
[0026] Turning to FIGS. 6 and 7, shown therein are close-up,
cross-sectional views of the lower end of the pump 108. The shaft
120 includes a lower ring groove 152 that is configured to accept a
conventional two-piece ring (not shown) that would be used in a
fixed impeller pump to capture the compression within the impeller
stack. The two-piece ring has been replaced with a lower adapter
154 for the floating impeller design of the pump 108.
Cross-sectional and perspective views of lower adapter 154 are
shown in FIGS. 9 and 10, respectively. The lower adapter 154
includes two lower ring halves 156a, 156b. Each of the two lower
ring halves 156a, 156b has a width that is configured to fit
tightly within the lower ring groove 152. Each of the lower ring
halves 156a, 156b further includes a lower adapter snap ring groove
158 and a lower adapter shoulder 160.
[0027] During assembly, the two lower ring halves 156a, 156b are
placed into the lower ring groove 152 and approximated. A lower
adapter snap ring 162 can then be placed into the lower adapter
snap ring groove 158 to hold the two lower ring halves 156a, 156b
together within the lower ring groove 152. In other embodiments,
set screws or clamps are used to hold the two lower ring halves
156a, 156b together. Once assembled, the lower adapter 154 remains
fixed with the shaft 120 to contain and position the standard
spacers 132 and impellers 126 as they are allowed to move axially
along the shaft 120.
[0028] As best illustrated in FIG. 6, the lower adapter 154 can be
used in combination with the lower bearing support 138 to offset
down thrust carried along the shaft 120 while permitting the shaft
120 to lift downstream in the event the up thrust forces exceed the
down thrust forces. The outer diameter of the lower adapter 154 is
smaller than the inner diameter of the lower bearing support 138.
This clearance allows the lower adapter 154 to move inside the
lower bearing support 138, where the lower adapter should 160 can
push the bearing spacer 136 and any standard spacers 132 downstream
along the shaft 120 within the tolerances provided by the spaces
between the various components connected to the shaft 120.
[0029] Thus, the upper adapter 142 and lower adapter 154 provide an
efficient mechanism for positioning and retaining the standard
spacers 132, bearing spacers 136, impellers 126 and other
components disposed along the outside of the shaft 120. The upper
adapter 142 and lower adapter 154 permit the conversion of a
conventional compression shaft into a "floater" shaft without
additional machining operations to the shaft 120. The ability to
quickly and easily convert a compression shaft into a floater shaft
reduces inventory demands and improves part interchangeability.
Shafts removed from older fixed impeller pumps can be easily
reclaimed, converted and installed in a floating impeller pump with
the upper and lower adapters 142, 154.
[0030] It is to be understood that even though numerous
characteristics and advantages of various embodiments of the
present invention have been set forth in the foregoing description,
together with details of the structure and functions of various
embodiments of the invention, this disclosure is illustrative only,
and changes may be made in detail, especially in matters of
structure and arrangement of parts within the principles of the
present invention to the full extent indicated by the broad general
meaning of the terms in which the appended claims are expressed. It
will be appreciated by those skilled in the art that the teachings
of the present invention can be applied to other systems without
departing from the scope and spirit of the present invention.
* * * * *