U.S. patent application number 12/826493 was filed with the patent office on 2010-12-30 for carrier for plunger during disassembly.
This patent application is currently assigned to WEIR SPM, INC.. Invention is credited to John E. Hawes.
Application Number | 20100325888 12/826493 |
Document ID | / |
Family ID | 43379160 |
Filed Date | 2010-12-30 |
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United States Patent
Application |
20100325888 |
Kind Code |
A1 |
Hawes; John E. |
December 30, 2010 |
CARRIER FOR PLUNGER DURING DISASSEMBLY
Abstract
A carrier that holds a plunger for a reciprocating pump during
maintenance. Maintenance of the pump typically includes repacking
of the packing that surrounds the plunger and revalving of the
pump's inlet and outlet valve. To allow repacking or revalving, the
pump is disassembled and the plunger is removed. The carrier mates
with the pump to hold and support weight of the plunger during
disassembly, allowing one person to perform pump revalving and
repacking.
Inventors: |
Hawes; John E.; (Southlake,
TX) |
Correspondence
Address: |
BRACEWELL & GIULIANI LLP
P.O. BOX 61389
HOUSTON
TX
77208-1389
US
|
Assignee: |
WEIR SPM, INC.
Fort Worth
TX
|
Family ID: |
43379160 |
Appl. No.: |
12/826493 |
Filed: |
June 29, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61221947 |
Jun 30, 2009 |
|
|
|
Current U.S.
Class: |
29/888.021 ;
29/281.1 |
Current CPC
Class: |
F04B 53/22 20130101;
Y10T 29/53961 20150115; Y10T 29/49238 20150115 |
Class at
Publication: |
29/888.021 ;
29/281.1 |
International
Class: |
F04B 39/14 20060101
F04B039/14 |
Claims
1. A carrier assembly for maintenance of a reciprocating pump,
comprising: a semi-circular mating end adapted to engage a cylinder
opening on the pump, a flange that projects radially outward from
the mating end and past the cylinder opening; and a semi-circular
nest projecting axially from a portion of the flange and away from
the cylinder opening having an upward facing concave surface for
receiving and supporting a plunger removed from within the
pump.
2. The carrier assembly of claim 1, further comprising a hinge that
that runs longitudinally along the carrier assembly.
3. The carrier assembly of claim 2, wherein the hinge comprises a
plurality of hinges that run longitudinally along the middle of the
mating end, flange, and nest to allow the carrier assembly to pivot
along the middle.
4. The carrier assembly of claim 1, wherein the mating end, flange,
and nest are fabricated as a single piece.
5. The carrier assembly of claim 1, wherein the mating end, flange,
and nest are fabricated as multiple pieces.
6. The carrier assembly of claim 1, wherein the mating end has
threads on an exterior surface for threadingly engaging
corresponding threads on an interior cylindrical surface of the
cylinder opening.
7. The carrier assembly of claim 1, wherein the nest is adjustable
to receive plungers of varying size.
8. The carrier assembly of claim 1, wherein the nest is
cantilevered from the mating end.
9. The carrier assembly of claim 1, wherein the nest has a length
approximately equal to a length of the plunger it supports.
10. The carrier assembly of claim 1, wherein the flange has an
outer diameter that is larger than an outer diameter of the
cylinder opening.
11. A carrier assembly for maintenance of a pump, comprising: a
semi-cylindrical mating end adapted to engage a cylinder opening on
the pump, the mating end having a threaded outer diameter for
threadingly engaging corresponding threads on an interior surface
of the cylinder opening, a semi-cylindrical flange on the mating
end and in contact with the exterior of the pump, the flange having
an outer diameter larger than an outer diameter of the cylinder
opening; an upward facing nest for receiving and supporting a
plunger removed from within the pump, the nest being cantilevered
from one end to the flange; and a hinge that that runs
longitudinally along the middle of the mating end, flange, and nest
to allow the carrier assembly to pivot along the middle.
12. The carrier assembly of claim 11, wherein the mating end,
flange, and nest are fabricated as a single piece.
13. The carrier assembly of claim 11, wherein the mating end,
flange, and nest are fabricated as multiple pieces.
14. The carrier assembly of claim 11, wherein the nest is
adjustable to receive plungers of varying size.
15. The carrier assembly of claim 1, wherein the nest has a length
approximately equal a length of the plunger it supports.
16. A method for supporting a pump plunger during maintenance or
disassembly of a pump, comprising: removing a suction cover plate
from a cylinder opening on the pump; mating a semi-cylindrical
mating end to the cylinder opening on the pump, removing the
plunger from within the pump through the cylinder opening; and
holding and supporting the plunger on an upward facing concave
surface connected at one end to the mating end.
17. The method of claim 16, further comprising the steps of:
removing packing surrounding the pump plunger; and repacking an
area surrounding the plunger.
18. The method of claim 16, further comprising the step of
revalving an inlet or an outlet valve within the pump;
19. The method of claim 16, wherein the step of mating a
semi-cylindrical mating end to the cylinder opening comprises
screwing the mating end into the cylinder opening.
20. The method of claim 16, wherein only one person is required to
perform the steps of maintenance or disassembly.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority to provisional application
61/221,947, filed Jun. 30, 2009, and is herein incorporated by
reference in its entirety.
FIELD OF THE INVENTION
[0002] This invention relates in general to plungers used in
reciprocating pumps, and, in particular, to a carrier that holds
the plunger during maintenance.
BACKGROUND OF THE INVENTION
[0003] Various kinds of pumps can be used in oilfield operations.
One type of pump, for example, is a reciprocating pump. The
reciprocating pump can be used to pump fluid such as chemicals,
cement, or other media into a well. Reciprocating pumps typically
increase the pressure within a cylinder by reciprocating a plunger
longitudinally within the cylinder. Packing is generally used
around the plunger and the plunger reciprocates as a crankshaft
located within the pump rotates. As the plunger moves away from the
cylinder, the pressure of the fluid inside chamber decreases
creating a differential pressure across an inlet valve that allows
the fluid to enter the cylinder. As plunger moves longitudinally
towards the cylinder, the pressure of the fluid inside of the
cylinder increases until the differential pressure across an outlet
valve that allows fluid to exit cylinder.
[0004] Maintenance of the pump, typically includes repacking of the
packing surrounding the plunger and revalving of the inlet and
outlet valves mentioned above. To allow repacking or revalving, the
pump is disassembled by removing a suction cover plate and removing
the plunger. Additional pump components, such as connecting rods
and pony rods may need to be stroked out to push out the plunger.
However, the plunger is heavy and requires at least one person to
be in position to pull and support the weight of the plunger.
Another person would repack and revalve the pump in the meantime.
Thus, two people are required to perform maintenance on the
pump.
[0005] Thus, a technique would be desired that makes pump
maintenance and disassembly safer, less time consuming, and less
labor intensive.
SUMMARY OF THE INVENTION
[0006] In an embodiment of the present invention, a carrier
assembly is connected to a reciprocating pump for supporting a
plunger removed from the pump during maintenance or disassembly. A
semi-cylindrical mating end can engage a cylinder opening on the
pump. The cylinder opening, previously covered by a suction cover
plate, has threads on an interior surface. The mating end screws
into the cylinder opening, with a semi-cylindrical flange on the
mating end being in contact with the exterior of the pump along a
periphery of the cylinder opening.
[0007] In an embodiment of the present invention, an upward facing
concave surface or nest for receiving and supporting the plunger is
connected at one end to the flange of the mating end. The nest is
cantilevered and holds and supports the weight of the plunger
during maintenance or disassembly of the pump. Further, the nest
has approximately a length equal to that of the plunger it
supports.
[0008] A hinge runs longitudinally down the middle of the carrier
assembly to allow the assembly to fold or pivot about the hinge.
Further, the nest may be adjustable to allow handling of varying
sizes of plungers. The carrier assembly may be a single piece or
fabricated from multiple pieces.
[0009] The carrier assembly thus advantageously provides a safer
way to maintain and disassemble pumps because the carrier assembly,
and not a person, supports the weight of the plunger. This also
results in a less time consuming, and less labor intensive method
of maintaining and disassembling the pumps as only one person, as
opposed to two, is needed to perform maintenance procedures such as
repacking and revalving of the pump.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a schematic side view illustration of a prior art
reciprocating pump;
[0011] FIG. 2 is a sectional view of the pump of FIG. 1;
[0012] FIG. 3 is an enlarged perspective view of one embodiment of
a carrier connected to a cylinder opening to receive and hold the
plunger, constructed in accordance with the invention.
[0013] FIG. 4 is an enlarged frontal view of one embodiment of the
carrier connected to a cylinder opening to receive and hold the
plunger, constructed in accordance with the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0014] Referring to FIGS. 1 and 2, reciprocating pump assembly or
pump 12 includes a crankshaft housing 13 that houses the power
portion of reciprocating pump 12. Stay rods 15 connect crankshaft
housing 13 to a fluid end 17 having a set of cylinders 37 (FIG. 2).
Each cylinder 37 is in communication with a fluid inlet 19 and a
fluid outlet 21. As shown in FIG. 2, a suction cover plate 22
connects to an end of each cylinder 37 opposite the crankshaft
housing 13. 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.
[0015] Referring to FIG. 2, a portion of reciprocating pump 12
housed within crankshaft housing 13 is shown. Crankshaft housing 13
houses a crankshaft 25, which is typically mechanically connected
to a motor (not shown). The motor rotates crankshaft 25 in order to
drive reciprocating pump 12 (FIG. 1). In one embodiment, crankshaft
25 is cammed so that fluid is pumped from each cylinder 37 at
alternating times. As is readily appreciable by those skilled in
the art, alternating the cycles of pumping fluid from each of
cylinders 37 helps minimize the primary, secondary, and tertiary
(et al.) forces associated with reciprocating pump 12 (FIG. 1).
[0016] A bull gear 24 is mechanically connected to crankshaft 25
and is rotated by a motor through pinion gear 26. A connector rod
27 is connected to the crankshaft 25 at one end. The connector rod
27 connects to a crosshead 29 through a crosshead wrist pin 31,
which holds connector rod 27 longitudinally relative to crosshead
29. The connector rod 27 pivots within the crosshead bushing 34 as
crankshaft 25 rotates with the other end of connector rod 27. A
pony rod 33 extends from crosshead 29 in a longitudinally opposite
direction from crankshaft 25. Connector rod 27 and crosshead 29
convert rotational movement of crankshaft 25 into longitudinal
movement of pony rod 33.
[0017] A plunger 35 is connected to pony rod 33 for pumping the
fluid passing through cylinder 37. Packing 36 is mounted in the
inner diameter of cylinder 37 and surrounds plunger 35. A packing
nut 38 is threaded into the cylinder housing 17, and acts to
maintain the packing 36 in the proper position within cylinder 37.
Cylinder 37 includes an interior or cylinder chamber 39, which is
where plunger 35 pressurizes the fluid being pumped by
reciprocating pump 12 (FIG. 1). Cylinder 17 also typically includes
an inlet valve 41 and an outlet valve 43. Valves 41 and 43 are
usually spring-loaded valves and are actuated by a predetermined
differential pressure. Inlet valve 41 actuates to control fluid
flow through fluid inlet 19 into cylinder chamber 39, and outlet
valve 43 actuates to control fluid flow through fluid outlet 21
from cylinder chamber 39.
[0018] Plunger 35 reciprocates, or moves longitudinally toward and
away from cylinder 17, as crankshaft 25 rotates. As plunger 35
moves longitudinally away from cylinder chamber 39, the pressure of
the fluid inside chamber 39 decreases creating a differential
pressure across inlet valve 41, which actuates valve 41 and allows
the fluid to enter cylinder chamber 39 from fluid inlet 19. The
fluid being pumped enters cylinder chamber 39 as plunger 35
continues to move longitudinally away from cylinder chamber 39
until the pressure difference between the fluid inside chamber 39
and the fluid in fluid inlet 19 is small enough for inlet valve 41
to actuate to its closed position. As plunger 35 begins to move
longitudinally towards cylinder chamber 39, the pressure of the
fluid inside of cylinder chamber 39 begins to increase. Fluid
pressure inside cylinder chamber 39 continues to increase as
plunger 35 approaches cylinder 17 until the differential pressure
across outlet valve 43 is large enough to actuate valve 43 and
allow the fluid to exit cylinder 17 through fluid outlet 21. In one
embodiment, fluid is only pumped across one side of plunger 35,
therefore reciprocating pump 12 is a single-acting reciprocating
pump.
[0019] Maintenance of the pump 12, typically includes repacking of
the packing 36 surrounding the plunger 35 and revalving of the
inlet and outlet valves 41, 43. To allow repacking or revalving,
the pump 12 is disassembled by removing the suction cover plate 22
and removing the plunger 35. The connector rod 27 and pony rod 33
can be stroked out to push the plunger 35 out the opening 53 (FIG.
3) previously closed by cover plate 22. Repacking and revalving,
can thus require two people as the plunger 35 is heavy and someone
needs to be in position to pull and support the weight of plunger
35.
[0020] Referring to FIGS. 3 and 4, an embodiment of a carrier
assembly 50 is shown. The carrier assembly 50 includes a threaded
semi-circular annular mating end 52 shown coaxially set within a
correspondingly contoured opening 53. A semi-circular nest 54 is
shown in the embodiment of FIG. 3 that is coaxial with and
projecting from a side of the mating end 52 outside of the opening
53. The nest 54 is elongated and has an upper surface profiled so
the plunger 35 can be set thereon during disassembly. The mating
end 52 has a partial set of threads 57 on its outer surface and a
semi-cylindrical flanged portion 58 on an end outside of the
opening 53. The flanged portion 58 extends radially past the
cylinder opening 53 and is in contact with an exterior of the
cylinder housing 17 adjacent the cylinder opening 53. Cylinder
opening 53 has a threaded inner radius so the cover plate 22 can be
set therein. The partial set of threads 57 on end 52 mate with the
threads (not shown) in opening 53. A hinge 56 runs longitudinally
along the carrier assembly 50 to allow the assembly 50 to fold
longitudinally along the middle. Alternatively, a plurality of
hinges can be utilized; optionally, the carrier assembly 50 can be
a single piece. The threads 57 on the mating end 52 may engage the
threads in the cylinder opening 53 after the suction cover plate 22
is removed. Once the assembly 50 is screwed in place, the nest 54
forms an upward facing, concave surface that can receive and hold
the plunger 35 during disassembly. Carrier assembly 50 is thus
cantilever supported and may be at least as long as the plunger 35.
After maintenance is complete, the plunger 35 can be placed back
into the cylinder opening 53 and the carrier assembly 50 can be
removed. The suction cover plate 22 can then be placed back in the
cylinder opening 53.
[0021] In an additional embodiment, the carrier assembly 50 is
fabricated from multiple pieces, with the mating end 52 being
separate from the nest 54.
[0022] In another embodiment (not shown), the mating end 52 is not
threaded. Instead a hinge is located at the cylinder opening 53 to
mate with a hinge on the mating end 52.
[0023] In another embodiment (not shown), a plurality of vertical
ribs or protrusions are formed on either side of the cylinder
opening 53. A plurality of slots formed on the mating end 52 can
slidingly engage the ribs to support the carrier assembly 50.
[0024] In another embodiment (not shown), the concave and upward
facing surface of the nest 54 may be adjusted to receive plungers
35 of varying size.
[0025] Reciprocating pumps 12 are large, and complex pieces of
equipment with many parts that may have to be replaced as they wear
out. Making the disassembly safer and less time consuming is thus
desirable because it makes pump maintenance safer less labor
intensive. By using a carrier assembly 50 that can mate with the
cylinder opening 53 and that can hold the plunger 35 during
disassembly, the need for two people to remove the plunger 35 is
eliminated. Thus, revalving and repacking can be performed by one
person.
[0026] This written description uses examples to disclose the
invention, including the best mode, and also enable a person of
ordinary skill in the art to practice the invention, including
making and using any devices or systems and performing any
incorporated methods. These embodiments are not intended to limit
the scope of the invention. The patentable scope of the invention
is defined by the claims, and may include other examples that occur
to those skilled in the art. Such other examples are intended to be
within the scope of the claims if they have structural elements
that do not differ from the literal language of the claims, or if
they include equivalent structural elements with insubstantial
differences from the literal language of the claims.
* * * * *