U.S. patent application number 14/195196 was filed with the patent office on 2014-10-30 for offset valve bore for a reciprocating pump.
This patent application is currently assigned to S.P.M. Flow Control, Inc.. The applicant listed for this patent is S.P.M. Flow Control, Inc.. Invention is credited to Jacob A. Bayyouk, John Bruce Clayfield Davies, Donald Mackenzie, David M. Manson.
Application Number | 20140322034 14/195196 |
Document ID | / |
Family ID | 46198008 |
Filed Date | 2014-10-30 |
United States Patent
Application |
20140322034 |
Kind Code |
A1 |
Bayyouk; Jacob A. ; et
al. |
October 30, 2014 |
OFFSET VALVE BORE FOR A RECIPROCATING PUMP
Abstract
A fluid end 15 for a multiple reciprocating pump assembly 12
comprises at least three plunger bores 61 or 91, each for receiving
a reciprocating plunger 35. Each plunger bore has a plunger bore
axis 65 or 95. The plunger bores are arranged across the fluid end
to define a central plunger bore and lateral plunger bores located
on either side of the central plunger bore. The fluid end 15 also
comprises at least three respective suction valve bores 59 or 89 in
fluid communication with the plunger bores. Each suction valve bore
can receive a suction valve 41 and has a suction valve bore axis 63
or 93. The fluid end 15 also comprises at least three respective
discharge valve bores 57 or 87 in fluid communication with the
plunger bores. Each discharge valve bore can receive a discharge
valve 43 and has a discharge valve bore axis 63 or 93. At least one
of the axes of at least one of the suction and discharge valve
bores is offset in the fluid end from its respective plunger bore
axis.
Inventors: |
Bayyouk; Jacob A.;
(Richardson, TX) ; Manson; David M.;
(Newtonmearns, GB) ; Mackenzie; Donald; (Glasgow,
GB) ; Davies; John Bruce Clayfield; (Glasgow,
GB) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
S.P.M. Flow Control, Inc. |
Fort Worth |
TX |
US |
|
|
Assignee: |
S.P.M. Flow Control, Inc.
Fort Worth
TX
|
Family ID: |
46198008 |
Appl. No.: |
14/195196 |
Filed: |
March 3, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
13314745 |
Dec 8, 2011 |
8668470 |
|
|
14195196 |
|
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|
|
61421453 |
Dec 9, 2010 |
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Current U.S.
Class: |
417/53 ;
417/269 |
Current CPC
Class: |
F04B 53/16 20130101;
F04B 47/00 20130101; F04B 23/06 20130101; F04B 1/00 20130101; F04B
39/122 20130101; F04B 27/00 20130101; F04B 1/0456 20130101 |
Class at
Publication: |
417/53 ;
417/269 |
International
Class: |
F04B 1/053 20060101
F04B001/053 |
Claims
1-41. (canceled)
42. A method of pumping fluid, the method comprising: conveying
fluid from a first flowpath to a second flowpath that is located
above the first flowpath and that defines a first longitudinal
center axis that is perpendicular to the first flowpath; conveying
the fluid from the second flowpath and into a pump chamber that is
located above the second flowpath and thus also above the first
flowpath; pressurizing the fluid within the pump chamber,
comprising reciprocatingly driving a plunger in the pump chamber
along a second longitudinal center axis that is perpendicular to
the first longitudinal center axis and either intersects, or is
horizontally spaced from, the first longitudinal center axis;
conveying the pressurized fluid out of the pump chamber via a third
flowpath that is located above the pump chamber, is opposed to the
second flowpath, and defines a third longitudinal center axis that
is perpendicular to the second longitudinal center axis and is
either horizontally spaced in a parallel relation from, or coaxial
with, the first longitudinal center axis defined by the second
flowpath so that a plunger horizontal spacing is defined between
the second longitudinal center axis and at least one of the first
and third longitudinal center axes; and delivering the pressurized
fluid from the third flowpath to a fourth flowpath that is: located
above the pump chamber and thus also above the second flowpath and
the first flowpath; perpendicular to the third flowpath and the
second flowpath; and spaced from the first flowpath in a parallel
relation.
43. The method of pumping fluid of claim 42, wherein
reciprocatingly driving the plunger along the second longitudinal
center axis comprises moving the plunger away from the pump
chamber; wherein conveying the fluid from the second flowpath and
into the pump chamber comprises actuating, to a first open
position, a first valve located in the second flowpath and thus
below the pump chamber; wherein the first valve located below the
pump chamber is actuated to the first open position in response to
moving the plunger away from the pump chamber; and wherein
actuating the first valve located below the pump chamber to the
first open position allows the fluid to enter the pump chamber via
the second flowpath.
44. The method of pumping fluid of claim 43, wherein pressurizing
the fluid within the pump chamber further comprises actuating, to a
first closed position, the first valve located below the pump
chamber to prevent the fluid from exiting the pump chamber via the
second flowpath.
45. The method of pumping fluid of claim 43, wherein
reciprocatingly driving the plunger along the second longitudinal
center axis further comprises moving the plunger toward the pump
chamber; wherein conveying the pressurized fluid out of the pump
chamber via the third flowpath comprises actuating, to a second
open position, a second valve that is located in the third flowpath
and thus above the pump chamber, and that is opposed to the first
valve located in the second flowpath and below the pump chamber;
wherein the second valve located above the pump chamber is actuated
to the second open position in response to moving the plunger
toward the pump chamber; and wherein actuating the second valve
located above the pump chamber to the second open position allows
the fluid to exit the pump chamber via the third flowpath.
46. The method of pumping fluid of claim 45, wherein, during moving
the plunger toward the pump chamber, the plunger is located within
the pump chamber, the first valve is located below the plunger, and
the second valve is located above the plunger, so that the plunger
is located between the first and second valves.
47. The method of pumping fluid of claim 42, wherein: the second
longitudinal center axis, along which the plunger is
reciprocatingly driven, intersects the first longitudinal center
axis defined by the second flowpath; the third longitudinal center
axis defined by the third flowpath is horizontally spaced in a
parallel relation from the first longitudinal center axis defined
by the second flowpath; and the plunger horizontal spacing is
defined between the second longitudinal center axis, along which
the plunger is reciprocatingly driven, and the third longitudinal
center axis defined by the third flowpath.
48. The method of pumping fluid of claim 42, wherein: the second
longitudinal center axis, along which the plunger is
reciprocatingly driven, is horizontally spaced from the first
longitudinal center axis defined by the second flowpath; the third
longitudinal center axis defined by the third flowpath is coaxial
with the first longitudinal center axis defined by the second
flowpath; and the plunger horizontal spacing is defined between the
second longitudinal center axis, along which the plunger is
reciprocatingly driven, and both of the coaxial third and first
longitudinal center axes defined by the third and second flowpaths,
respectively.
49. The method of pumping fluid of claim 42, wherein: the second
longitudinal center axis, along which the plunger is
reciprocatingly driven, is horizontally spaced from the first
longitudinal center axis defined by the second flowpath; and the
third longitudinal center axis defined by the third flowpath is
horizontally spaced in a parallel relation from the first
longitudinal center axis defined by the second flowpath.
50. The method of pumping fluid of claim 49, wherein: the second
longitudinal center axis, along which the plunger is
reciprocatingly driven, is horizontally spaced from the first
longitudinal center axis defined by the second flowpath; the third
longitudinal center axis defined by the third flowpath is
horizontally spaced in a parallel relation from the first
longitudinal center axis defined by the second flowpath to the same
degree as the second longitudinal center axis is horizontally
spaced from the first longitudinal center axis so that the third
longitudinal center axis intersects the second longitudinal center
axis; and the plunger horizontal spacing is defined between the
second longitudinal center axis, along which the plunger is
reciprocatingly driven, and the first longitudinal center axis
defined by the second flowpath.
51. A system for pumping fluid, the system comprising: means for
conveying fluid from a first flowpath to a second flowpath that is
located above the first flowpath and that defines a first
longitudinal center axis that is perpendicular to the first
flowpath; means for conveying the fluid from the second flowpath
and into a pump chamber that is located above the second flowpath
and thus also above the first flowpath; means for pressurizing the
fluid within the pump chamber, comprising means for reciprocatingly
driving a plunger in the pump chamber along a second longitudinal
center axis that is perpendicular to the first longitudinal center
axis and either intersects, or is horizontally spaced from, the
first longitudinal center axis; means for conveying the pressurized
fluid out of the pump chamber via a third flowpath that is located
above the pump chamber, is opposed to the second flowpath, and
defines a third longitudinal center axis that is perpendicular to
the second longitudinal center axis and is either horizontally
spaced in a parallel relation from, or coaxial with, the first
longitudinal center axis defined by the second flowpath so that a
plunger horizontal spacing is defined between the second
longitudinal center axis and at least one of the first and third
longitudinal center axes; and means for delivering the pressurized
fluid from the third flowpath to a fourth flowpath that is: located
above the pump chamber and thus also above the second flowpath and
the first flowpath; perpendicular to the third flowpath and the
second flowpath; and spaced from the first flowpath in a parallel
relation.
52. The system for pumping fluid of claim 51, wherein means for
reciprocatingly driving the plunger along the second longitudinal
center axis comprises means for moving the plunger away from the
pump chamber; wherein means for conveying the fluid from the second
flowpath and into the pump chamber comprises means for actuating,
to a first open position, a first valve located in the second
flowpath and thus below the pump chamber; wherein the first valve
located below the pump chamber is actuated to the first open
position in response to moving the plunger away from the pump
chamber; and wherein actuating the first valve located below the
pump chamber to the first open position allows the fluid to enter
the pump chamber via the second flowpath.
53. The system for pumping fluid of claim 52, wherein means for
pressurizing the fluid within the pump chamber further comprises
means for actuating, to a first closed position, the first valve
located below the pump chamber to prevent the fluid from exiting
the pump chamber via the second flowpath.
54. The system for pumping fluid of claim 52, wherein means for
reciprocatingly driving the plunger along the second longitudinal
center axis further comprises means for moving the plunger toward
the pump chamber; wherein means for conveying the pressurized fluid
out of the pump chamber via the third flowpath comprises means for
actuating, to a second open position, a second valve that is
located in the third flowpath and thus above the pump chamber, and
that is opposed to the first valve located in the second flowpath
and below the pump chamber; wherein the second valve located above
the pump chamber is actuated to the second open position in
response to moving the plunger toward the pump chamber; and wherein
actuating the second valve located above the pump chamber to the
second open position allows the fluid to exit the pump chamber via
the third flowpath.
55. The system for pumping fluid of claim 54, wherein, during
moving the plunger toward the pump chamber, the plunger is located
within the pump chamber, the first valve is located below the
plunger, and the second valve is located above the plunger, so that
the plunger is located between the first and second valves.
56. The system for pumping fluid of claim 51, wherein: the second
longitudinal center axis, along which the plunger is
reciprocatingly driven, intersects the first longitudinal center
axis defined by the second flowpath; the third longitudinal center
axis defined by the third flowpath is horizontally spaced in a
parallel relation from the first longitudinal center axis defined
by the second flowpath; and the plunger horizontal spacing is
defined between the second longitudinal center axis, along which
the plunger is reciprocatingly driven, and the third longitudinal
center axis defined by the third flowpath.
57. The system for pumping fluid of claim 51, wherein: the second
longitudinal center axis, along which the plunger is
reciprocatingly driven, is horizontally spaced from the first
longitudinal center axis defined by the second flowpath; the third
longitudinal center axis defined by the third flowpath is coaxial
with the first longitudinal center axis defined by the second
flowpath; and the plunger horizontal spacing is defined between the
second longitudinal center axis, along which the plunger is
reciprocatingly driven, and both of the coaxial third and first
longitudinal center axes defined by the third and second flowpaths,
respectively.
58. The system for pumping fluid of claim 51, wherein: the second
longitudinal center axis, along which the plunger is
reciprocatingly driven, is horizontally spaced from the first
longitudinal center axis defined by the second flowpath; and the
third longitudinal center axis defined by the third flowpath is
horizontally spaced in a parallel relation from the first
longitudinal center axis defined by the second flowpath.
59. The system for pumping fluid of claim 58, wherein: the second
longitudinal center axis, along which the plunger is
reciprocatingly driven, is horizontally spaced from the first
longitudinal center axis defined by the second flowpath; the third
longitudinal center axis defined by the third flowpath is
horizontally spaced in a parallel relation from the first
longitudinal center axis defined by the second flowpath to the same
degree as the second longitudinal center axis is horizontally
spaced from the first longitudinal center axis so that the third
longitudinal center axis intersects the second longitudinal center
axis; and the plunger horizontal spacing is defined between the
second longitudinal center axis, along which the plunger is
reciprocatingly driven, and the first longitudinal center axis
defined by the second flowpath.
60. A method of manufacturing a fluid end for a reciprocating pump
assembly, the method comprising: providing a block comprising
horizontally spaced, opposing first and second end portions;
forming in the block a center plunger bore, the center plunger bore
defining a longitudinal center axis; forming in the block first and
second lateral plunger bores on either side of, and horizontally
spaced in a parallel relation from, the center plunger bore so that
the first and second lateral plunger bores are symmetric about the
longitudinal center axis and thus respective horizontal spacings
between the longitudinal center axis and the first and second
lateral plunger bores are equal; forming in the block first and
second lateral valve bores on either side of, horizontally spaced
from, and perpendicular to, the center plunger bore so that: the
first and second lateral valve bores are asymmetric about the
longitudinal center axis defined by the center plunger bore, the
horizontal spacing between the longitudinal center axis and the
first lateral valve bore is greater than the horizontal spacing
between the longitudinal center axis and the second lateral valve
bore, the first lateral valve bore is disposed between the first
end portion and the center plunger bore, and the second lateral
valve bore is disposed between the second end portion and the
center plunger bore; and connecting an end support to the first end
portion; wherein the horizontal spacing between the first end
portion, to which the first end support is connected, and the first
lateral valve bore is less than the horizontal spacing between the
second end portion and the second lateral valve bore.
61. The method of claim 60, wherein the end support comprises a
plate, and wherein connecting the end support to the first end
portion of the block comprises bolting the plate to the first end
portion.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to provisional application
61/421,453 filed Dec. 9, 2010.
TECHNICAL FIELD
[0002] An arrangement is disclosed whereby a valve bore is offset
from a plunger bore in a fluid end of a reciprocating pump to
relieve stress.
BACKGROUND OF THE DISCLOSURE
[0003] In oil field operations, reciprocating pumps are used for
various purposes. Reciprocating pumps are used for operations such
as cementing, acidizing, or fracturing of a subterranean well.
These reciprocating pumps run for relatively short periods of time,
but they operate on a frequent basis and oftentimes at extremely
high pressures. A reciprocating pump is mounted to a truck or a
skid for transport to various well sites and must be of appropriate
size and weight for road and highway regulations.
[0004] Reciprocating pumps or positive displacement pumps for oil
field operations deliver a fluid or slurry, which may carry solid
particles (for example, a sand proppant), at pressures up to 20,000
psi to the wellbore. A known pump for oilfield operations includes
a power end driving more than one plunger reciprocally in a
corresponding fluid end or pump chamber. The fluid end may comprise
three or five plunger bores arranged transversely across a fluid
head, and each plunger bore may be intersected by suction and
discharge valve bores. In a known reciprocating pump, the axis of
each plunger bore intersects perpendicularly with a common axis of
the suction and discharge valve bores.
[0005] In a mode of operating a known three plunger bore
reciprocating pump at high fluid pressures (for example, around or
greater than 20,000 psi), a maximum pressure and thus stress can
occur within a given pump chamber as the plunger moves
longitudinally in the fluid end towards top dead center (TDC),
compressing the fluid therein. One of the other pump chambers will
be in discharge and thus at a very low pressure, and the other pump
chamber will have started to compress the fluid therein.
[0006] It has been discovered that, in a given pump chamber, the
areas of highest stress occur at the intersection of each plunger
bore with its suction and discharge valve bores as the plunger
moves to TDC. The occurrence of high stress at these areas can
shorten the life of the fluid end.
[0007] JP 2000-170643 is directed to a multiple reciprocating pump
having a small size. The pump has three piston bores in which the
pistons reciprocate but, so that a compact pump configuration can
be provided, the axis of each suction valve bore is arranged
perpendicularly to its respective discharge valve bore (that is, so
that there is a laterally directed discharge from the fluid
end).
[0008] JP 2000-170643 also teaches that a limit as to the volume of
fluid that can be pumped by a small reciprocating pump is the size
of suction and discharge valve bores. Contrary to the embodiments
disclosed herein, the teaching of JP 2000-170643 is not concerned
with reducing stresses arising at the intersection of piston,
suction and discharge bores. Rather, JP 2000-170643 teaches moving
the axes of each of the outside suction and discharge valve bores
outwardly with respect to their plunger bore axis to enable the
volume of each of the suction and discharge valve bores to be
increased. Thus, with an increased pump speed, an increased
volumetric flow can be achieved with a pump that still has a
similar overall dimensional profile. In addition, JP 2000-170643
teaches that the valve bores are moved outwardly without increasing
the amount of material between the suction and discharge bores.
This is because the reconfiguration of the pump in JP 2000-170643
is not concerned with reducing stresses within the pump in use.
SUMMARY
[0009] In a first aspect there is disclosed a fluid end for a
multiple reciprocating pump assembly. The multiple reciprocating
pump assembly may, for example, comprise three or five plunger
bores, and may find application in oilfield operations and/or may
operate with fluids at high pressures (for example, as high as
20,000 psi or greater). The fluid end comprises at least three
plunger bores (for example, three or five plunger bores), each can
receive a reciprocating plunger, and each can have a plunger bore
axis. The plunger bores can be arranged across the fluid end to
define a central plunger bore and lateral plunger bores located on
either side of the central plunger bore (for example, one or two
lateral plunger bores located on either side of the central plunger
bore, to define a fluid end with three or five plunger bores
respectively). At least three respective suction valve bores (for
example, three or five suction valve bores) can be provided for and
be in fluid communication with the plunger bores. Each suction
valve bore can receive a suction valve and have a suction valve
bore axis. At least three respective discharge valve bores (e.g.
three or five discharge valve bores) can be provided for and be in
fluid communication with the plunger bores. Each discharge valve
bore can receive a discharge valve and have a discharge valve bore
axis. In accordance with the first aspect, at least one of the axes
of at least one of the suction and discharge valve bores is offset
in the fluid end from its respective plunger bore axis. The offset
can be such that overall stress within the fluid in use is reduced
(e.g. as the plunger moves to TDC). This reduction in overall
stress is a surprising discovery, with an outcome that the useful
operating life of the fluid end can be increased.
[0010] In certain embodiments for each of the plunger bores, the
suction valve bore may oppose the discharge valve bore. This
arrangement is easier to manufacture, maintain and service than,
for example, arrangements in which the axis of each suction valve
bore is e.g. perpendicular to the discharge valve bore. In
addition, the opposing bore arrangement may induce less stress in
the fluid end in use than, for example, a perpendicular bore
arrangement.
[0011] In certain embodiments for each of the plunger bores, the
axes of the suction and discharge valve bores may be aligned, for
even greater ease of manufacture, maintenance and service. In other
certain embodiments, the at least one offset axis may be offset in
an amount ranging from about 10% to about 60% of the diameter of
the plunger bore. In certain other embodiments, the offset axis may
be offset in an amount ranging from about 20% to about 50%, or from
about 30% to about 40%, of the diameter of the plunger bore.
[0012] In other certain embodiments, the at least one offset axis
may be offset in an amount ranging from about 0.5 to about 2.5
inches. In certain other embodiments, the offset axis may be offset
in an amount ranging from about 1.5 to 2.5 inches. These dimensions
may represent an optimal range for many bore diameters of fluid end
configurations employed in fracking pumps in oilfield and related
applications.
[0013] In a second aspect, there is provided a fluid end for a
multiple reciprocating pump assembly. The fluid end comprises at
least three plunger bores each for receiving a reciprocating
plunger, with each plunger bore having a plunger bore axis. The
plunger bores are arranged across the fluid end to define a central
plunger bore and lateral plunger bores located on either side of
the central plunger bore. At least three respective suction valve
bores are in fluid communication with the plunger bores. Each
suction valve bore is able to receive a suction valve and has a
suction valve bore axis. At least three respective discharge valve
bores are in fluid communication with the plunger bores. Each
discharge valve bore is able to receive a discharge valve and has a
discharge valve bore axis. In accordance with the second aspect at
least one of the axes of at least one of the suction and discharge
valve bores is offset in the fluid end from its respective plunger
bore axis in such a manner that overall stress within the fluid end
in use is reduced. This reduction in overall stress is a surprising
discovery with an outcome that the useful operating life of the
fluid end can be increased.
[0014] In certain embodiments for each of the plunger bores, the
suction valve bore may oppose the discharge valve bore.
[0015] In certain embodiments for each of the plunger bores, the
axes of the suction and discharge valve bores may be aligned.
[0016] In other certain embodiments, the at least one offset axis
may be offset in an amount ranging from about 10% to about 60% of
the diameter of the plunger bore. In certain other embodiments, the
offset axis may be offset in an amount ranging from about 20% to
about 50%, or from about 30% to about 40%, of the diameter of the
plunger bore.
[0017] In other certain embodiments, the at least one offset axis
may be offset in an amount ranging from about 0.5 to about 2.5
inches. In certain other embodiments, the offset axis may be offset
in an amount ranging from about 1.5 to 2.5 inches. These dimensions
may represent an optimal range for many bore diameters of fluid end
configurations employed in fracking pumps in oilfield and related
applications.
[0018] In a third aspect, there is provided a fluid end for a
multiple reciprocating pump assembly. The fluid end comprises at
least three plunger bores each for receiving a reciprocating
plunger. Each plunger bore has a plunger bore axis, with the
plunger bores being arranged across the fluid end to define a
central plunger bore and lateral plunger bores located on either
side of the central plunger bore. At least three respective suction
valve bores are in fluid communication with the plunger bores. Each
suction valve bore is able to receive a suction valve and has a
suction valve bore axis. At least three respective discharge valve
bores are in fluid communication with the plunger bores. Each
discharge valve bore is able to receive a discharge valve and has a
discharge valve bore axis. Each discharge valve bore opposes a
respective suction valve bore. In accordance with the third aspect,
at least one of the axes of at least one of the suction and
discharge valve bores is offset in the fluid end from its
respective plunger bore axis.
[0019] In certain embodiments for each of the plunger bores, the
axes of the suction and discharge valve bores may be aligned.
[0020] In other certain embodiments, the at least one offset axis
may be offset in an amount ranging from about 10% to about 60% of
the diameter of the plunger bore. In certain other embodiments, the
offset axis may be offset in an amount ranging from about 20% to
about 50%, or from about 30% to about 40%, of the diameter of the
plunger bore.
[0021] In other certain embodiments, the at least one offset axis
may be offset in an amount ranging from about 0.5 to about 2.5
inches. In certain other embodiments, the offset axis may be offset
in an amount ranging from about 1.5 to 2.5 inches. These dimensions
may represent an optimal range for many bore diameters of fluid end
configurations employed in fracking pumps in oilfield and related
applications.
[0022] In certain embodiments at least one of the axes of the
suction and discharge valve bores for each of the lateral plunger
bores may be inwardly or outwardly offset. For example, for a three
or five plunger bore fluid end that has a central plunger bore
(such as may be arranged on a central axis of the fluid end), the
inward or outward offset may comprise a lateral offset (that is,
towards or away from a given one of the sides of the fluid end).
The offset may, in addition, be with respect to an axis of the
central plunger bore, or in further embodiments with respect to the
central axis of the fluid end in the case of offsetting a central
suction and/or discharge valve bore.
[0023] In certain embodiments, for the lateral plunger bores, for
reasons of uniformity of design and stress reduction in the fluid
end, the at least one offset axis may be inwardly or outwardly
offset to the same extent as the other at least one offset
axis.
[0024] In certain embodiments, the axes of both the suction and
discharge valve bores may be inwardly or outwardly offset.
[0025] In certain embodiments, the axes of both the suction and
discharge valve bores may be inwardly or outwardly offset to the
same extent.
[0026] In other certain embodiments, the fluid end may comprise
three or five plunger bores, and three or five corresponding
suction and discharge valve bores.
[0027] In a fourth aspect, there is provided a fluid end for a
multiple reciprocating pump assembly. The fluid end comprises first
and second opposing sides having a longitudinal dimension, first
and second opposing end surfaces, a top surface having a
longitudinal dimension, and a bottom surface having a longitudinal
dimension. At least three plunger bores are provided, each for
receiving a reciprocating plunger, and each plunger bore having a
plunger bore axis. The plunger bores are arranged across the fluid
end to define a central plunger bore and lateral plunger bores
located on either side of the central plunger bore. At least three
respective suction valve bores are in fluid communication with the
plunger bores. Each suction valve bore is able to receive a suction
valve and has a suction valve bore axis. At least three respective
discharge valve bores are in fluid communication with the plunger
bores. Each discharge valve bore is able to receive a discharge
valve and has a discharge valve bore axis. In accordance with the
fourth aspect at least one of the axes of at least one of the
suction and discharge valve bores is offset in the fluid end from
its respective plunger bore axis. The offset can be such that
overall stress within the fluid end in use is reduced (for example
as the plunger moves to TDC). Again this reduction in overall
stress is a surprising discovery with an outcome that the useful
operating life of the fluid end can be increased.
[0028] In certain embodiments for each of the plunger bores, the
suction valve bore may oppose the discharge valve bore.
[0029] In other certain embodiments for each of the plunger bores,
the axes of the suction and discharge valve bores may be
aligned.
[0030] In other certain embodiments, the at least one offset axis
may be offset in an amount ranging from about 10% to about 60% of
the diameter of the plunger bore. In certain other embodiments, the
offset axis may be offset in an amount ranging from about 20% to
about 50%, or from about 30% to about 40%, of the diameter of the
plunger bore.
[0031] In other certain embodiments, the at least one offset axis
may be offset in an amount ranging from about 0.5 to about 2.5
inches. In certain other embodiments, the offset axis may be offset
in an amount ranging from about 1.5 to 2.5 inches. These dimensions
may represent an optimal range for many bore diameters of fluid end
configurations employed in fracking pumps in oilfield and related
applications.
[0032] In certain embodiments, at least one of the first and second
end surfaces may further comprise an end support. The end support
may be configured such that overall stress within the fluid in use
is reduced. The end support may comprise the arrangement or
addition of further material (for example, metal) to the fluid
end.
[0033] In other certain embodiments, the end support may add from
about 0.1% to about 25% to a portion of the longitudinal dimension
of the first and second opposing sides.
[0034] In certain embodiments, the end support may cover from about
20% to about 80% of the surface on at least one of the first and
second ends. In certain other embodiments the end support may cover
from about 30% to about 70%, or from about 40% to about 60%, or
around 50% of the surface on at least one of the first and second
ends.
[0035] In other certain embodiments, the end support may cover the
entire surface on at least one of the first and second ends.
[0036] In certain embodiments, the longitudinal dimension of the
bottom surface may be greater than the longitudinal dimension of
the top surface.
[0037] Other aspects, features, and advantages will become apparent
from the following detailed description when taken in conjunction
with the accompanying drawings, which are a part of this disclosure
and which illustrate, by way of example, principles of the fluid
end as disclosed herein.
DESCRIPTION OF THE FIGURES
[0038] Notwithstanding any other forms which may fall within the
scope of the fluid end as set forth in the Summary, specific
embodiments of the fluid end and reciprocating pump will now be
described, by way of example only, with reference to the
accompanying drawings.
[0039] In the Description of the Figures and in the Detailed
Description of Specific Embodiments, a pump that comprises three
plunger, suction and discharge bores is hereafter referred to as a
"triplex", and a pump that comprises five plunger, suction and
discharge bores is hereafter referred to as a "quint", being an
abbreviation of "quintuplex".
[0040] In the drawings:
[0041] FIGS. 1A and 1B illustrate, in sectional and perspective
views, an embodiment of a reciprocating pump. FIG. 1A may depict
either a triplex or quint, although FIG. 1B specifically depicts a
triplex.
[0042] FIGS. 1C and 1D illustrate, in end and perspective views, an
embodiment of a triplex fluid end for a reciprocating pump, in
which cover plates have been removed for clarity, to illustrate the
provision of end supports on opposing sides of the fluid end.
[0043] FIG. 2 schematically depicts an embodiment of a triplex,
being a partial section of FIG. 1A taken on the line 2-2, to
illustrate both lateral (or outside) valve bore pairs being offset
inwardly from their respective plunger bores.
[0044] FIG. 3 is an underside schematic view of the section of FIG.
2 to show a bolt pattern on a fluid end.
[0045] FIG. 4 schematically depicts another embodiment of a
triplex, being a partial section similar to FIG. 2, to illustrate
some of the valve bores outwardly offset from their respective
plunger bores.
[0046] FIG. 5 is an underside schematic view of the section of FIG.
4 to show a bolt pattern on a fluid end of a cylinder.
[0047] FIG. 6 schematically depicts another embodiment of a
triplex, being a partial section similar to FIG. 2 to illustrate
the valve bores offset to the left of their respective plunger
bores.
[0048] FIG. 7 is an underside schematic view of the section of FIG.
6 to show a bolt pattern on a fluid end of a cylinder.
[0049] FIG. 8 schematically depicts another embodiment of a
triplex, being a partial section similar to FIG. 2 to illustrate
discharge valve bores offset from respective plunger bores.
[0050] FIG. 9 schematically depicts another embodiment of a
triplex, being a partial section similar to FIG. 2 to illustrate
suction valve bores offset from respective plunger bores.
[0051] FIG. 10 schematically depicts a first embodiment of a quint,
being a partial section of FIG. 1A taken on the line 2-2, to
illustrate the two lateral valve bore pairs on either side of the
central valve bore pair being offset inwardly from their respective
plunger bores.
[0052] FIG. 11 is an underside schematic view of the section of
FIG. 10 to show a bolt pattern on a fluid end of a cylinder.
[0053] FIG. 12 is a similar view of the quint of FIG. 10, but
illustrates both the innermost and outermost lateral valve bore
pairs, and not the central valve bore pair, being offset outwardly
from their respective plunger bores.
[0054] FIG. 13 is a similar view of the quint of FIG. 10, but
illustrates all the valve bore pairs being offset to the left of
their respective plunger bores.
[0055] FIG. 14 is a similar view of the quint of FIG. 10, but
illustrates the innermost lateral valve bore pairs being offset
inwardly and the outermost lateral valve bore pairs being offset
outwardly, and the central valve bore pair not being offset, from
their respective plunger bores.
[0056] FIG. 15 is a similar view of the quint of FIG. 10, but
illustrates the innermost lateral valve bore pairs being offset
outwardly and the outermost lateral valve bore pairs being offset
inwardly, and the central valve bore pair not being offset, from
their respective plunger bores.
[0057] FIGS. 16 and 17 schematically depict side sectional
elevations as generated by finite element analysis (FEA), and taken
from opposite sides, through a triplex fluid end, to illustrate
where maximum stress, as indicated by FEA, occurs for the
intersection of a plunger bore with the suction and discharge valve
bores; with FIG. 16 showing no offset and FIG. 17 showing 2 inch
inward offset.
[0058] FIG. 18 is a data point graph that plot Von Mises yield
criterion (that is, for the maximum stress, in psi, as determined
by FEA) against the amount of valve bore offset (in inches) for a
single (mono) fluid end and a triplex fluid end.
[0059] FIGS. 19 and 20 are two different bar graphs that plot Von
Mises yield criterion (that is, for the maximum stress, in psi, as
determined by FEA) against different amounts of valve bore offset
(in inches), both inward and outward, for a single (mono) fluid end
and a triplex fluid end.
DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS
[0060] Referring to FIGS. 1A and 1B, an embodiment of a
reciprocating pump 12 housed within a crankshaft housing 13 is
shown. The crankshaft housing 13 may comprise a majority of the
outer surface of reciprocating pump 12. Stay rods 14 connect the
crankshaft housing 13 (the so-called "power end") to a fluid end
15. When the pump is to be used at high pressures (for instance, in
the vicinity of 20,000 psi or greater), up to four stay rods can be
employed for each plunger of the multiple reciprocating pump. The
stay rods may optionally be enclosed in a housing.
[0061] The pump 12 is a triplex having a set of three cylinders 16,
each including a respective plunger bore 17. The three (or, in the
case of a quint, five) cylinders/plunger bores can be arranged
transversely across the fluid end 15. A plunger 35 reciprocates in
a respective plunger bore 17 and, in FIG. 1A, the plunger 35 is
shown fully extended at its top dead centre position. In the
embodiment depicted, fluid is only pumped at one side 51 of the
plunger 35, therefore the reciprocating pump 12 is a single-acting
reciprocating pump.
[0062] Each plunger bore 17 is in communication with a fluid inlet
or suction manifold 19 and a fluid outlet side 20 in communication
with a pump outlet 21 (FIG. 1B). A suction cover plate 22 for each
cylinder 16 and plunger bore 17 is mounted to the fluid end 15 at a
location that opposes the plunger bore 17. The pump 12 can be
free-standing on the ground, can be mounted to a trailer that can
be towed between operational sites, or mounted to a skid such as
for offshore operations.
[0063] Crankshaft housing 13 encloses a crankshaft 25, which can be
mechanically connected to a motor (not shown). The motor rotates
the crankshaft 25 in order to drive the reciprocating pump 12. In
one embodiment, the crankshaft 25 is cammed so that fluid is pumped
from each cylinder 16 at alternating times. As is readily
appreciable by those skilled in the art, alternating the cycles of
pumping fluid from each of the cylinders 16 helps minimize the
primary, secondary, and tertiary (et al.) forces associated with
the pumping action.
[0064] A gear 24 is mechanically connected to the crankshaft 25,
with the crankshaft 25 being rotated by the motor (not shown)
through gears 26 and 24. A crank pin 28 attaches to the main shaft
23, shown substantially parallel to an axis A.sub.X of the
crankshaft 25. A connector rod 27 is connected to the crankshaft 25
at one end. The other end of connector rod 27 is secured by a
bushing to a crosshead or gudgeon pin 31, which pivots within a
crosshead 29 in housing 30 as the crankshaft 25 rotates at the one
end of the connector rod 27. The pin 31 also functions to hold the
connector rod 27 longitudinally relative to the crosshead 29. A
pony rod 33 extends from the crosshead 29 in a longitudinally
opposite direction from the crankshaft 25. The connector rod 27 and
the crosshead 29 convert rotational movement of the crankshaft 25
into longitudinal movement of the pony rod 33.
[0065] The plunger 35 is connected to the pony rod 33 for pumping
the fluid passing through each cylinder 16. Each cylinder 16
includes an interior or cylinder chamber 39, which is where the
plunger 35 compresses the fluid being pumped by reciprocating pump
12. The cylinder 16 also includes an inlet (or suction) valve 41
and an outlet (or discharge) valve 43. Usually the inlet and outlet
valves 41, 43 are arranged in an opposed relationship in cylinder
16 and may, for example, lie on a common axis.
[0066] The valves 41 and 43 are usually spring-loaded and are
actuated by a predetermined differential pressure. The inlet
(suction) valve 41 actuates to control fluid flow from the fluid
inlet 19 into the cylinder chamber 39, and the outlet (discharge)
valve 43 actuates to control fluid flow from the cylinder chamber
39 to the outlet side 20 and thence to the pump outlet 21.
Depending on the size of the pump 12, the plunger 35 may be one of
a plurality of plungers, for example, three or five plungers may be
utilized.
[0067] The plunger 35 reciprocates, or moves longitudinally, toward
and away from the chamber 39, as the crankshaft 25 rotates. As the
plunger 35 moves longitudinally away from the cylinder chamber 39,
the pressure of the fluid inside the chamber 39 decreases, creating
a differential pressure across the inlet valve 41, which actuates
the valve 41 and allows the fluid to enter the cylinder chamber 39
from the fluid inlet 19. The fluid continues to enter the cylinder
chamber 39 as the plunger 35 continues to move longitudinally away
from the cylinder 17 until the pressure difference between the
fluid inside the chamber 39 and the fluid in the fluid inlet 19 is
small enough for the inlet valve 41 to actuate to its closed
position.
[0068] As the plunger 35 begins to move longitudinally into the
cylinder 16, the pressure on the fluid inside of the cylinder
chamber 39 begins to increase. Fluid pressure inside the cylinder
chamber 39 continues to increase as the plunger 35 approaches the
chamber 39 until the differential pressure across the outlet valve
43 is large enough to actuate the valve 43 and allow the fluid to
exit the chamber 39 through the fluid outlet 21.
[0069] The inlet valve 41 is located within a suction valve bore 59
and the outlet valve 43 is located within a discharge valve bore
57. In the embodiment depicted, both valve bores 57, 59 are in
communication with, and extend orthogonally to the plunger bore 17.
The valve bores 57, 59 as shown are also co-axial (that is, lying
on a common axis, or with parallel axes), but they may be offset
relative to each other as described below.
[0070] It should be noted that the opposing arrangement of the
valve bores 57, 59 depicted in FIG. 1 is easier to manufacture (for
example, by casting and machining), and is easier to maintain and
easier to service than, for example, a perpendicular arrangement of
the valve bores (that is, where the axes of the bores are
perpendicular). In the opposing bores arrangement, the bores can be
easily accessed, packed, unpacked, serviced, etc from under and
above the fluid end, without interfering with inlet and outlet
manifolds.
In addition, it is understood that, where stress reduction in the
fluid end is desirable, the opposing arrangement of the valve bores
57, 59 may induce less stress in the fluid end, especially at high
operating pressures of 20,000 psi or greater, when compared with a
perpendicular or other angled bore arrangement.
[0071] In FIGS. 1A and 1B, the fluid end 15 is shown without an end
support and can be from about 36 to about 45 inches in length as
measured from the first and second opposing sides. An embodiment of
the fluid end 15 provides that the length is about 36 inches or
about 39 inches in length as measured from the first and second
opposing sides. A quintuplex fluid end can be from about 60 inches
to about 80 inches in length as measured from the first and second
opposing sides. An embodiment of the quintuplex fluid end has a
length of about 52 inches, 63 inches or about 70.5 inches.
[0072] Referring now to FIGS. 1C and 1D, a triplex fluid end 15'
for a reciprocating pump is illustrated. In these Figures the cover
plates are removed for clarity. The fluid end 15' of FIGS. 1C and
1D comprises a modified end in comparison to the fluid end 15 of
FIGS. 1A and 1B. In this regard, end supports in the form of
additional material regions 18A and 18B have been added to opposing
first 202 and second 204 sides of the fluid end 15'. In FIG. 1C the
regions 18A and 18B are shown by stippling. The additional material
may comprise the provision of extra metal in the fluid end during
its manufacture (for example, by casting). However, there may be
other ways of providing such end supports including bolt on plates,
supporting framework, and so on.
[0073] The distance between the first and second opposing sides 202
and 204 defines a longitudinal dimension 210 for the fluid end 15'.
The fluid end 15' also comprises a top surface 212 having a
longitudinal dimension 214 and a bottom surface 216 having a
longitudinal dimension 210. Because the additional material regions
18A and 18B are provided in a bottom portion of the first and
second opposing sides 202 and 204, the longitudinal dimension 210
for the bottom surface 216 is greater than the longitudinal
dimension 214 for the top surface 212. The longitudinal dimension
210 for a triplex fluid end 15' having an end support 18 can be
greater than 35 inches to 40 inches, from about 36.1 inches to
about 45 inches, from about 36.5 inches to about 39 inches, from
about 37 inches to about 39 inches, is about 38 inches, or is about
39 inches. The longitudinal dimension 210 for a quintuplex fluid
end having an end support 18 can be greater than 50 inches, greater
than 52 inches, from about 50 inches to about 80 inches, from about
52.1 inches to about 85 inches, from about 71 inches to about 85
inches, is about 56 inches, is about 67 inches, or is about 74.5
inches.
[0074] This form of end support may be employed where, for example,
one or both lateral (outside) valve bores 57, 59 are to be offset
outwardly in the fluid end. In such an instance, the additional
material in the regions 18A and 18B can function to reduce overall
stress within the fluid end. Generally, if one of the lateral valve
bores 57, 59 is offset outwardly in the fluid end then the
additional material region 18A or 18B will be provided just at that
end.
[0075] As depicted in the drawings, the additional material regions
18A and 18B may be dimensioned so as to add to the longitudinal
dimension of the fluid end. For example, the increase in
longitudinal dimension can range from about 0.1% to about 25% of
the length of the fluid end (being the distance between first and
second opposing sides).
[0076] As depicted in the drawings, the additional material regions
18A and 18B may be dimensioned so as to cover a proportion of the
first and second opposing sides of the fluid end. For example, the
regions 18A and 18B may each cover a proportion of its respective
side in an amount ranging from about 20% to about 80%. As shown in
FIG. 1D, each region 18A and 18B covers slightly greater than 50%
of its respective side. However, if required, the regions 18A and
18B may each cover up to 100% of the first and second opposing
sides of the fluid end.
[0077] As depicted in the drawings, the additional material regions
18A and 18B cover a lower part of their respective first and second
opposing sides of the fluid end. This can correspond with a region
or point of maximum stress arising from the outward offset of a
lateral suction valve bore. As a result, the longitudinal dimension
of the bottom part of the fluid end is greater than the
longitudinal dimension of the top part of the fluid end.
[0078] Referring now to FIG. 2, a partial sectional view of the
fluid end 15 of the pump 12 taken on the line 2-2 of FIG. 1A is
schematically depicted. In the embodiment of FIGS. 2 and 3, the
pump 12 is a triplex having three plunger bores 17 corresponding to
three cylinder bores. However, as described hereafter with
reference to FIGS. 10 to 15, the pump can have a different number
of cylinders and plunger bores, such as five. For a symmetric
triplex fluid end, a central bore of the three plunger bores lies
on a central axis of the fluid end, with the other two plunger
bores arranged evenly on either side of the central plunger bore.
The offset may be with respect to a central axis of the fluid
end.
[0079] In the embodiment of FIGS. 2 and 3 each of the three plunger
bores 17 is indicated schematically with the reference numeral 61
(that is, 61a, 61b and 61c); each of the three suction valve bores
is indicated schematically with the reference numeral 59 (i.e. 59a,
59b and 59c); and each of the three discharge valve bores is
indicated schematically with the reference numeral 57 (that is,
57a, 57b and 57c). Similarly, the axis of each plunger bore 61 is
indicated schematically with the reference numeral 65 (that is,
65a, 65b and 65c). Also, the common axis of each of the valve bores
59 and 57 is indicated schematically with the reference numeral 63
(that is, 63a, 63b and 63c). This nomenclature will also be used
hereafter with reference to each of the different triplex fluid end
embodiments described herein in FIGS. 2 to 9.
[0080] It has been discovered that the highest point of stress
concentration in pump 12 occurs at the intersection of a plunger
bore with the suction (or inlet) and discharge (or outlet) valve
bores. The maximum stress in the fluid end occurs when one plunger
(for example a lateral plunger) is approaching Top Dead Center
(TDC), another is approaching Bottom Dead Center (BDC), and a third
has just started moving from BDC to TDC.
[0081] It has further been discovered that, to reduce fluid end
stress, some or all of the lateral (outside) valve bores 57a, 57c,
59a, 59c at the discharge and suction side may be inwardly offset
so that an axis 65 of at least some of the plunger bores (that is,
the lateral plunger bore axes 65a 65c) does not intersect with a
common valve bore axis 63 such that at least one of the lateral
valve bore axis 63a or 63c is inwardly offset from its respective
lateral plunger bore axes 65a or 65c. This inward lateral offset
has been observed to noticeably reduce the stress in the fluid end
15 that arises as a result of fluid flowing therein, especially at
the high pressures that can be employed in oilfield operations (for
example, with oil well fracking fluid).
[0082] In the three cylinder triplex pump embodiment of FIGS. 2 and
3 the lateral (or outside) suction and discharge valve bores 59a,
57a and 59c, 57c are each shown as being inwardly offset and to the
same extent from the associated lateral (or outside) plunger bores
61a and 61c. The central discharge and suction valve bores 57b, 59b
are not offset from their respective plunger bores 61b. Thus, the
terminology "offset inwardly and to the same extent" can be
considered as meaning offset inwardly in relation, or with
reference, to the central plunger bore 61b and central valve bores
57b, 59b. In addition, the common axis 63a of the valve bores 59a,
57a is offset inwardly from the axis 65a of plunger bore 61a.
Further, the common axis 63c of the valve bores 59c, 57c is offset
inwardly and to the same extent from the axis 65c of the plunger
bore 61c.
[0083] Furthermore, whilst in this embodiment the amount of inward
offset from both the lateral plunger bores and axes toward the
central plunger bore and axis is the same, the amount of offset can
be different. For example, the suction and discharge valve bores on
one side can be more or less laterally offset to that of the
suction and discharge valve bores on the other side of the fluid
end. Additionally, either or both of the suction and discharge
valve bores on one side may be laterally offset by different
extents, or one may not be offset at all, and this offset may be
different to each of the suction and discharge valve bores on the
other side of the fluid end, which also may be offset differently
to each other.
[0084] In any case, the inward offsetting of both the lateral
suction and discharge valve bores 59a, 57a and 59c, 57c, by the
same amount and to the same extent, has been surprisingly observed
to reduce stress within the fluid end at the high fluid operating
pressures, as explained in Example 1.
[0085] As indicated above, in the three cylinder triplex pump
embodiment of FIGS. 2 and 3, the common axis 63b of the central
suction and discharge valve bores 59b, 57b intersects with axis 65b
of the central plunger bore 61b. It has been observed that in a
fluid end having three or more cylinders, there is less stress
concentration at the intersection of the central plunger bore 61b
with the central valve bores 57b, 59b as compared to the stress at
the intersections of the lateral bores and their respective
plungers, and hence offsetting the central valve bores 57b, 59b may
not be required. However, the embodiments of FIGS. 5 and 6 provide
that the central valve bores 59b, 57b and axes can also be offset
(e.g. maybe to a lesser degree than the lateral bores) to reduce
stress concentration thereat.
[0086] In the embodiment of FIGS. 2 and 3, each common axis 63 of
the valve bores 57 and 59 extends perpendicularly to the plunger
bore axis 65, although the lateral axes 63a and 63c do not
intersect.
[0087] The amount of inward offset of the valve bores 59, 57 and
the plunger bores 61 can be significant. For example, for 4.5 inch
diameter bores, the valve bore 59, 57, may be inwardly offset 2
inches from a respective plunger bore 61. The amount of inward
offset may be measured from axis to axis. For example, the distance
can be set by referring to the distance that the common axis 63a or
63c of the valve bores 57a or 57c and 59a or 59c is offset either
from its respective plunger bore axis 65a or 65c, or from the
central plunger bore axis 65b (or where the central valve bore is
not offset, as offset from the central common axis 63b of the valve
bores 57b and 59b).
[0088] In any case, the amount of the offset can be about 40% of
the diameter of the plunger bore, though it can, for example, range
from about 10% to about 60%. Where the inward offset of each of the
lateral valve bores 59a, 59c and 57a, 59c is 2 inches, the distance
from axis 63a of valve bores 59a, 57c to axis 63c of valve bores
59c, 57c thus becomes 4 inches closer than in known fluid ends of
similar dimensions.
[0089] In other embodiments, the inward offset of each lateral
valve bore can range from about 0.25 inch to about 2.5 inch, from
about 0.5 inch to about 2.0 inch, from about 0.75 inch to about 2.0
inch, from about 1 inch to about 2 inch, from about 0.25 inch to
about 1.25 inch, from about 1.5 inch to about 2.5 inch, from about
1.5 inch to about 2.0 inch, or from about 1.5 inch to about 1.75
inch.
[0090] This moving of the lateral valve bores inwardly can
represent a significant reduction in the overall dimension and
weight of the fluid end. However, one limit to the amount of inward
offset of the lateral (or outside) valve bores toward the central
valve bore can be the amount of supporting metal between the valve
bores.
[0091] When the lateral (or outside) suction valve bores 59 are
inwardly offset as described with reference to FIG. 2, modification
of the suction manifold 19 (FIGS. 1A and 1B) can allow for its easy
connection to the new fluid end 15. Similar modifications can be
employed for the discharge manifold.
[0092] A conventional suction manifold corresponds to conventional
bolt patterns that would be located at a greater distance than that
occurring between the valve bores 59a, 57a, to valve bores 59c, 57c
depicted in FIG. 2. The new bolt pattern 71 is illustrated in FIG.
3, which schematically depicts an underside of the fluid end 15. In
this regard, the distance 74 of the axis 63a of the valve bore 59a
to the axis 63c of the valve bore 59c is shorter than the distance
72 between the axis 65a of the plunger bore 61a to the axis 65c of
the plunger bore 61c, the latter of which corresponds to the
conventional bolt pattern. It is feasible to modify and utilize a
manifold with the new bolt pattern.
[0093] Referring now to the embodiment of FIGS. 4 and 5, the
lateral (or outer) discharge and suction valve bores 57a, 59a, 57c,
59c are depicted as being offset outwardly from their respective
plunger bores 61a, 61c. For example, the axis 63a of the valve
bores 59a, 57a is outwardly offset from the axis 65a of the plunger
bore 61a. Similarly, the axis 63c of the valve bores 59c, 57c is
outwardly offset from the axis 65c of the plunger bore 61c.
Although the amount of offset of the valve bores 59a and 59c
depicted in FIGS. 4 and 5 are equal, each valve bore 59a, 59c may
have a different offset.
[0094] The axis 63b of the central valve bores 57b, 59b is again
shown intersecting with the axis 65b of the plunger bore 61b.
However, the central valve bores 59b, 57b may also be offset. In
the embodiment of FIGS. 4 and 5, as in the embodiment of FIGS. 2
and 3, the suction manifold 19 can be modified to connect to the
new fluid end 15. The new bolt pattern 71' is illustrated in the
underside view of the fluid end 15 in FIG. 5. In the new bolt
pattern 71', the distance 74' from axis 63a of valve bore 59a to
axis 63c of valve bore 59c is greater than the distance 72' between
axis 65a of plunger bore 61a and axis 65c of plunger bore 61c, the
latter of which is the conventional bolt pattern. Again, it is
feasible to modify and utilize suction and discharge manifolds 19
with the new bolt pattern. However, where the amount of outward
offset from the central valve bore is too close to the outer sides
of the fluid end, this can cause an increase in stress as discussed
hereafter with respect to the data of Example 2. This can be
compensated for by adding a support end, such as the additional
material regions 18A and 18B illustrated in FIGS. 1C and 1D, to the
opposing end surfaces of the fluid end. The reduction in overall
stress within the fluid end as a result of providing such support
ends is also discussed hereafter with respect to the stress data of
Example 2.
[0095] Referring now to the embodiment shown in FIGS. 6 and 7, the
suction valve bores 59a, 59b, 59c and the discharge valve bores
57a, 57b, 57c corresponding to each plunger bore 61a, 61b, 61c are
offset to one side (in this case to the left of the fluid end) and
to the same extent, or alternatively may be offset to the right
(not shown). Thus, the common axis 63 (i.e. 63a, 63b, 63c) of each
of the valve bores 59, 57 is offset to the left of an axis 65 (i.e.
65a, 65b, 65c) of each respective plunger bore 61. Due to the
uniform offset of the valve bores 59, 57 associated with each of
the plunger bores 61, a bolt patterns 77 can also be spaced
uniformly. The distance 78 from the common axis 63a of the valve
bores 59a, 57a to the common axis 63c of the valve bores 59c, 57c
is equal to the distance 79 between the axis 65a of the plunger
bore 61a to the axis 65c of the plunger bore 61c, the latter of
which is the conventional bolt pattern. Thus, in this embodiment, a
conventional suction manifold 19 (FIG. 1) may be bolted onto the
fluid end 15 depicted in FIG. 7.
[0096] In another embodiment shown in FIG. 8, the discharge valve
bores 57a, 57b, 57c are shown being offset to the same extent to
the right (or to the left--not shown) while the suction valve bores
59a, 59b, 59c remain aligned with each plunger bore 61a, 61b, 61c.
Thus, an axis 63' of each of the discharge valve bores 57 is offset
to the right of an axis 65 of each respective plunger bore 61,
whereas the axis 63'' of each suction valve bore 59 intersects the
axis 65 of its respective plunger bore 61. Due to the uniform
offset of the discharge valve bores 57 associated with each of the
plunger bores 61, the bolt patterns are also spaced uniformly. In
this regard, the distance 81 from the axis 63'a of the valve bore
57a to the axis 63'c of the valve bore 57c is equal to the distance
82 between the axis 65a of the plunger bore 61a to the axis 65c of
the plunger bore 61c, the latter of which is the conventional bolt
pattern. Thus, the fluid end of this embodiment employs a
conventional discharge manifold set up. In this embodiment, the
offset of at least one of the valve bores, here the discharge valve
bores 57, can again provide a reduction in stress within the fluid
end at the cross bore intersections.
[0097] In another embodiment shown in FIG. 9, the suction valve
bores 59a, 59b, 59c can be offset by the same extent to the right
(or to the left--not shown) while the discharge valve bores 57a,
57b, 57c remain aligned with each plunger bore 61a, 61b, 61c. Thus,
an axis 63'' of each of the suction valve bores 59 is offset to the
right of an axis 65 of each respective plunger bore 61, whereas the
axis 63' of each discharge, valve bore 57 intersects the axis 65 of
its respective plunger bore 61. Due to the uniform offset of the
discharge valve bores 57 associated with each of the plunger bores
61, the bolt patterns are also spaced uniformly. In this regard,
the distance 83 from an axis 63''a of the valve bore 59a to an axis
63''c of the valve bore 59c is equal to the distance 84 between an
axis 65a of the plunger bore 61a to the axis 65c of the plunger
bore 61c, the latter of which is the conventional bolt pattern.
Thus, a conventional suction manifold 19 (FIG. 1) may be bolted
onto the fluid end 15. As with the embodiment described in FIG. 8,
the offset of at least one of the valve bores, here the suction
valve bore 59, can provide a reduction in stress at the cross bores
of the fluid end 15.
[0098] It should be noted that the offsetting of just the discharge
valve bores 57, or the offsetting of just the suction valve bores
59, can also be employed in a quint fluid end set-up.
[0099] Referring now to FIGS. 10 and 11, a first embodiment of a
quint fluid end (that is, a quintuplex fluid end having five
plungers, five suction valves and five discharge valve bores) is
shown. FIG. 10 is a partial section of FIG. 1A taken on the line
2-2 (i.e. noting that FIG. 1A can also relate to a quint). FIG. 11
is an underside schematic view of the section of FIG. 10 to show a
bolt pattern on a fluid end. For a symmetrical quint fluid end, a
central bore of the five plunger bores lies on a central axis of
the fluid end, with two plunger bores arranged evenly on either
side of the central plunger bore. Again, offset may be with respect
to a central axis of the fluid end.
[0100] In the embodiment of FIGS. 10 and 11 each of the five
plunger bores 17 is indicated schematically with the reference
numeral 91 (that is, 91a, 91b, 91c, 91d and 91e); each of the three
suction valve bores is indicated schematically with the reference
numeral 89 (that is, 89a, 89b, 89c, 89d and 89e); and each of the
three discharge valve bores is indicated schematically with the
reference numeral 87 (that is, 87a, 87b, 87c, 87d and 87e).
Similarly, the axis of each plunger bore 91 is indicated
schematically with the reference numeral 95 (that is, 95a, 95b,
95c, 95d and 95e). Also, the common axis of each of the valve bores
89, 87 is indicated schematically with the reference numeral 93
(that is, 93a, 93b, 93c, 93d and 93e). This nomenclature will also
be used hereafter with reference to the different quint fluid end
embodiments described herein.
[0101] In the quint fluid end embodiment of FIGS. 10 and 11 the two
lateral valve bores 89a and 87a; 89b and 87b; 89d and 87d; 89e and
87e on each side of the central valve bores 89c and 87c are shown
as being inwardly offset from their respective plunger bores 91a,
91b, 91d and 91e.
[0102] In the embodiment of FIGS. 10 and 11 each of the two lateral
valve bores on either side of the central valve bores is inwardly
offset by the same amount and to the same extent. However, with a
quint fluid end, many more variations and offset combinations are
possible than with a triplex fluid end. For example, just two of
the lateral discharge valve bores 87a and 87b (and not their
respective suction valve bores 89a and 89b) may be inwardly offset,
and these two discharge valve bores 87a and 87b may each be offset
by the same or different amounts. This inward offset may not be
employed for the opposite two lateral discharge valve bores 87d and
87e. The inward offset may be employed for the opposite two lateral
suction valve bores 89a and 89b, which latter two might also each
be offset by the same or by different amounts, and so on.
[0103] Referring to the new bolt pattern of FIG. 11, modification
of the suction manifold can allow for its easy connection to the
new quint fluid end. As mentioned above, a conventional suction
manifold corresponds to conventional bolt patterns that are located
at a greater distance than that occurring between the valve bores
89a, 87a, to valve bores 89e, 87e depicted in FIG. 11. The new bolt
pattern 101 is illustrated in FIG. 11, which schematically depicts
an underside of the fluid end 15. In this regard, the distance 104
of the axis 93a of the valve bore 89a to the axis 93e of the valve
bore 89e is shorter than the distance 102 between the axis 95a of
the plunger bore 91a to the axis 95e of the plunger bore 91e, the
latter of which corresponds to the conventional bolt pattern.
Again, it is feasible to modify and utilize a manifold with the new
bolt pattern.
[0104] Referring now to FIG. 12, another embodiment of a quint
fluid end is shown. FIG. 12 shows a similar view to the quint of
10, but in this embodiment illustrates the outward offsetting from
their respective plunger bores 91a, 91b, 91d and 91e of the
outermost and innermost lateral valve bores 89a, 87a, 89b, 87, 89d,
87d and 89e, 87e on each side of the non-offset central valve bores
89c and 87c.
[0105] Referring now to FIG. 13, yet another embodiment of a quint
fluid end is shown. FIG. 13 shows a similar view to the quint of
FIG. 10, but in this embodiment illustrates the offsetting to the
left, (although it may be, to the right) of each of the valve bores
89, 87.
[0106] Referring now to FIG. 14, yet a further embodiment of a
quint fluid end is shown. FIG. 14 shows a similar view to the quint
of FIG. 10, but in this embodiment illustrates the inward
offsetting from their respective plunger bores 91b and 91d of the
innermost lateral valve bores 89b, 87b and 89d, 87d, and the
outward offsetting of the outermost lateral valve bores 89a, 87a
and 89e, 87e. The central valve bores 89c, 87c are not offset.
[0107] Referring now to FIG. 15, a yet further embodiment of a
quint fluid end is shown. FIG. 15 shows a similar view to the quint
of FIG. 10, but in this embodiment illustrates the outward
offsetting from their respective plunger bores 91b and 91d of the
innermost lateral valve bores 89b, 87b and 89d, 87d, and the inward
offsetting of the outermost lateral valve bores 89a and 87a, and
89e and 87e. Again, the central valve bores 89c and 87c are not
offset.
[0108] Whilst not shown, with the quint fluid end many other
combinations of valve bore offsets are possible, and material
(metal) within the fluid end may be adjusted accordingly.
EXAMPLES
[0109] Non-limiting examples are provided to illustrate how the
offsetting of a lateral valve bore can surprisingly and
unexpectedly reduce stress in a fluid end during operation at high
pressures as compared to a fluid end having conventional unmodified
valve bores. Example 1 discusses data modeled for an inward
offsetting, and Example 2 discusses data modeled for an outward
offsetting. In the following examples, finite element analysis
(FEA) tests were conducted for a triplex fluid end, although it was
noted that the findings also applied to a quintuplex fluid end.
[0110] The FEA experiments were conducted to compare the stresses
induced in a number of new fluid end configurations having three
cylinders against a known (existing and unmodified) three cylinder
fluid end configuration. In the unmodified fluid end configuration
the axis of each plunger bore intersected perpendicularly with a
common axis of the suction and discharge valve bores.
[0111] In these FEA stress tests, each fluid end was subjected to a
working fluid pressure of 15,000 psi, commensurate with that
experienced in usual applications. The pressure of fluid in the
lateral discharge bore was observed by FEA to be 16,800 psi.
[0112] FIGS. 16 and 17 show two of the schematics of a triplex
fluid end that were generated by FEA at these model fluid
pressures. In FIGS. 16 and 17 regions of stress are shaded
according to the key adjacent to FIG. 17. The view in FIG. 16 is
from one side of the fluid end and shows no offset of the suction
and discharge valve bores 59 and 57. The head of the arrow A
illustrates where maximum stress occurred at the intersection of
the plunger bore 61 with the suction valve bore 59 (that is, where
the plunger bore 61 first intersects with the suction valve bore
59). This indicates that, in operation, stress in the fluid end may
be reduced, for example, by offsetting just one of the suction
valve bores 59. However, greater stress reduction may also be
achieved by offsetting of the opposing lateral suction and
discharge valve bores 59 and 57.
[0113] The view in FIG. 17 is from an opposite side of the fluid
end and shows a 2 inch inward offset of the discharge and suction
valve bores 57 and 59. The offset was measured from the centerline
of the respective plunger bore 65a, 65c. The head of the arrow A
illustrates where maximum stress occurred at the intersection of
the plunger bore 61 with the suction valve bore 59 (i.e. where the
suction valve bore 59 intersects with the extension of the plunger
cylinder which terminates at the suction cover plate 22). In other
words, the region of maximum concentrated stress has been shifted
out of the intersection of the plunger bore 61 with the suction
valve bore 59.
Example 1
Inward Offsetting
[0114] In the first set of tests a single (or mono) block fluid end
and a triplex fluid end were each modeled. The single block fluid
end was modeled with one of the valve bores offset and an end was
modified with an end support. With the triplex fluid end one of the
lateral (outside) valve bores was inwardly offset, as compared with
a triplex pump in which both lateral valve bores may be inwardly
offset. The fluid end configurations modeled included one (e.g.
lateral) discharge 57 and suction 59 bore being inwardly offset by
1.5 inches and by 2 inches.
[0115] The stress result modeled by FEA was correlated to the Von
Mises yield criterion (in psi) and the results were plotted for
each of zero offset (that is, an existing fluid end), and 1.5
inches and 2 inches offset (that is, a new fluid end) and offset
with an end support. The results are shown in the graphs of FIG. 18
(which shows data point results for both 1.5 inches and 2 inches
offset) and FIG. 19 (which represents the results for 1.5 inches
and 2 inches inward offset in a bar chart).
[0116] As can be seen, the FEA modeling of the tested fluid ends
resulted in a 2 inch inward offset of a triplex fluid end having
the greatest amount of stress reduction as compared to no offset
and to 1.5 inches inward offset for the triplex or single block.
Moreover, the single block fluid end with an offset surprisingly
did not produce much of reduction in stress. However, as soon as
the end was modified with the end support that was 2 inches in
length (or thickness) and extended along the entire exterior end
the stress dropped noticeably (FIG. 19). The overall stress
reduction in the triplex fluid end for a 2 inch inward offset was
noted to be approximately 30% (that is, from .about.97,000 psi to
less than 69,000 psi as shown in FIGS. 18 and 19). It was noted
that such a stress reduction would be likely to significantly
extend the useful operating life of the fluid end.
Example 2
Outward Offsetting
[0117] In the second set of tests, the outward offsetting of one of
the lateral (outside) valve bores was modeled. The fluid end
configurations tested included one lateral suction 57 and suction
59 bore being outwardly offset by 1.5 inches and by 2 inches. The
results for a 2 inch offset are shown in FIG. 20. For a 2 inch
outward offset in a triplex, with no adjustment for a resultant
thinning in adjacent wall material, the FEA modeling resulted in an
increase in stress at the intersection of plunger and valve bores
(2.sup.nd rightmost bar). However, in the FEA model, as soon as the
wall was modified with an end support that was 2 inches in length
(or thickness) extending along the entire surface of the outer wall
(see e.g. FIGS. 1C and 1D), the overall stress reduction in the
fluid end was around 29% (from .about.97,000 psi to less than
69,000 psi). Again, it was noted that such a stress reduction would
be likely to significantly extend the useful operating life of the
fluid end.
[0118] In the foregoing description of certain embodiments,
specific terminology has been resorted to for the sake of clarity.
However, the disclosure is not intended to be limited to the
specific terms so selected, and it is to be understood that each
specific term includes other technical equivalents which operate in
a similar manner to accomplish a similar technical purpose. Terms
such as "left" and right", "front" and "rear", "above" and "below",
"top" and "bottom" and the like are used as words of convenience to
provide reference points and are not to be construed as limiting
terms.
[0119] In this specification, the word "comprising" is to be
understood in its "open" sense, that is, in the sense of
"including", and thus not limited to its "closed" sense, that is
the sense of "consisting only of". A corresponding meaning is to be
attributed to the corresponding words "comprise", "comprised" and
"comprises" where they appear.
[0120] In addition, the foregoing describes only some embodiments
of the fluid end and reciprocating pump, and alterations,
modifications, additions and/or changes can be made thereto without
departing from the scope and spirit of the disclosed embodiments,
the embodiments being illustrative and not restrictive.
[0121] Furthermore, the fluid end and reciprocating pump have
described in connection with what are presently considered to be
the most practical and preferred embodiments, it is to be
understood that the fluid end and reciprocating pump are not to be
limited to the disclosed embodiments, but on the contrary, is
intended to cover various modifications and equivalent arrangements
included within the spirit and scope of the disclosure. Also, the
various embodiments described above may be implemented in
conjunction with other embodiments, e.g., aspects of one embodiment
may be combined with aspects of another embodiment to realize yet
other embodiments. Further, each independent feature or component
of any given assembly may constitute an additional embodiment.
* * * * *