Note: Descriptions are shown in the official language in which they were submitted.
VALVE SEAT EXTRACTION DEVICE
BACKGROUND OF THE INVENTION
[0001] The present invention relates generally to tools for the removal of
valve seats and in
particular to a valve seat puller useful, for example, in the petroleum
industries.
[0002] Pumps used for the pumping of fluid used in oil and natural gas
extraction operations
may include valve seats that wear over time and must be replaced. These valve
seats are usually
press fit into a casting or the like and must be pulled free from within the
casting using
considerable force, for example, obtained through a hydraulic cylinder.
[0003] Valve seat pullers are known which can extend into a casting and
pass through a
valve seat to extract the valve seat. The pullers include jaws with outwardly
extending teeth for
engaging a backside of the valve seat and for providing a shaft which can
attach to a hydraulic
cylinder to apply the necessary force to the valve seat. Because of the
considerable force applied
to the valve seat, a method of preventing the jaws from retracting during this
process may be
required.
[0004] U.S. patent 9,302,380 describes a valve seat puller where the jaws
are pressed
outward by a tapered cone attached to the valve puller shaft. When the shaft
is pulled upward
after the jaws have been fit through a valve seat, the cone shaft urges the
jaws outward with a
pressure comparable to that required for the extraction.
SUMMARY OF THE INVENTION
[0005] The present invention provides a valve seat puller eliminating the
need for a
cumbersome cone shaft which may require extra clearance beneath the valve seat
for operation
and whose movement relative to the jaws makes the application of downward
pressure on the
seat puller, necessary to engage with the valve seat, more difficult. Instead,
the present invention
provides a puller body attached to the upper ends of the jaws holding the jaws
in the extended
position through a combination of jaw support surfaces that bias the lower
edges of the jaws
outward with upward force and a positive locking through downward extension of
the shaft into
the puller body. The invention also provides an ability to release the shaft
from the puller body
to permit faster setup and removal of the valve seat.
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Specifically, the present invention provides a valve seat puller having a
first and second
jaw extending along an insertion axis and pivoting with respect each other so
that lower ends of
the first and second jaws may move together and apart perpendicular to the
insertion axis, the
lower ends of the first and second jaws including outwardly extending ledges.
A puller body
attaches to upper ends of the first and second jaws and communicates with a
shaft extendable
along the insertion axis to guide the first and second jaws to a valve seat.
The puller body allows
the first and second jaws to move together to pass through the valve seat in
an engagement mode
and holds the lower ends of the first and second jaws apart so that the ledges
engage a backside
of the valve seat for removal of the valve seat in a removal mode.
[0006] It is thus a feature of at least one embodiment of the invention to
provide a valve
puller that can engage a valve seat without an ancillary cone expander
positioned between the
jaws.
[0007] The first and second jaws may be attached to each other by a
transversely extending
hinge allowing the first and second jaws to pivot about a transverse axis
perpendicular to the
insertion axis.
[0008] It is thus a feature of at least one embodiment of the invention to
provide a simple
method of pivoting the jaws with respect to the puller body.
[0009] The puller body may urge the upper ends of the first and second jaws
together when
the puller body pulls against the upper ends of the first and second jaws in
an axial motion with
respect to the first and second jaws that is required for removal of the valve
seat.
[0010] It is thus a feature of at least one embodiment of the invention to
provide an outward
force on the jaws to prevent slippage during seat extraction.
[0011] The puller body may include an axial-threaded bore for receiving the
shaft
therethrough so that rotation of the shaft with respect to the puller body
locks the first and second
jaws in separation engaging a valve seat for removal.
[0012] It is thus a feature of at least one embodiment of the invention to
provide a positive
locking of the jaws to prevent slippage.
[0013] The first and second jaws may attach to the puller body by means of
upwardly
extending T-bars fitting within corresponding transverse T-slots in the puller
body.
[0014] It is thus a feature of at least one embodiment of the invention to
provide a robust
joint that permits the necessary motion of the first and second jaws.
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[0015] The T-slots in the puller body may slope downward toward the
insertion axis.
[0016] It is thus a feature of at least one embodiment of the invention to
provide a simple
way of biasing the jaws outward with upward force on the puller body.
[0017] The upper surface of the T-bars may engage the shaft passing through
the threaded
bore to lock the first and second jaws apart.
[0018] It is thus a feature of at least one embodiment of the invention to
provide a simple
method of locking the jaws using the shaft itself.
[0019] The valve seat puller may further include a spring biasing the lower
ends of the first
and second jaws apart and wherein the spring is a helical compression spring
positioned below
the hinge with respect to the puller body in between the first and second
jaws.
[0020] It is thus a feature of at least one embodiment of the invention to
provide a simple
spring biasing system that protects the spring against damage.
[0021] The hinge includes a threaded hinge pin removable therefrom for
separation of the
first and second jaws.
[0022] It is thus a feature of at least one embodiment of the invention to
permit ready
disassembly of the valve seat puller for in-field cleaning or repair.
[0023] The lower ends of the first and second jaws may include a bevel
surface engaging an
upper lip of the valve seat with axial movement of the puller body toward the
valve seat to press
the lower ends of the first and second jaws together.
[0024] It is thus a feature of at least one embodiment of the invention to
provide simple
engagement between the valve seat puller and the valve seat through downward
pressure on the
shaft without ancillary motion or sliding.
[0025] These particular objects and advantages may apply to only some
embodiments falling
within the claims and thus do not define the scope of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] Fig. 1 is a simplified cross-section of a valve having a valve seat
showing positioning
of the valve seat puller of the present invention for removal of the valve
seat;
[0027] Fig. 2 is a top-, front-, left-, and right-side drawing of a valve
seat puller jaw forming
a left and right jaw of the valve seat puller of Fig. 1 together with a
perspective rendering of the
same.
[0028] Fig. 3 is a top-, front-, and side-elevational view of a puller body
of the seat puller of
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the present invention showing a cross-sectional elevation along line A-A and a
perspective
rendering of the puller body;
[0029] Fig. 4 is a right-side and front view of the assembled valve seat
puller in partial cross-
section showing a first stage of inserting the valve seat puller into a valve
seat where the valve
seat compresses the lower ends of the valve seat puller jaws together and
showing a perspective
partial cross-sectional view of the same;
[0030] Fig. 5 is a figure similar to Fig. 4 showing the valve seat puller
in partial passage
through the valve seat with the valve seat puller jaws compressed together;
[0031] Fig. 6 is a figure similar to Figs. 4 and 5 showing expansion of the
valve seat puller
jaws outward after passage through the valve seat so that ledges of the jaws
engage a backside of
the seat for retraction of the same; and
[0032] Fig. 7 is a figure similar to Figs. 4-6 showing a threading inward
of the shaft of the
valve seat puller into the puller body to lock valve seat jaws in an extended
position.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0033] Referring now to Fig. 1, a valve seat puller 10 of the present
invention may include a
threaded shaft 12 extending along the insertion axis 14 and attached at its
lower end to a seat
puller body 16 by a threaded coupling thereto. Extending from beneath the seat
puller body 16
are first and second jaws 18a and 18b attached at their upper ends to the seat
puller body 16 to be
retained axially with respect to the seat puller body 16. Lower ends of the
first and second jaws
18 hold at their lower tips outwardly extending ledges 22. The lower ends of
the first and second
jaws 18 may pivot with respect to each other inward and outward as indicated
by arrows 20 to
pass through a ring-shaped valve seat 24 and to extend on the other side of
the valve seat 24 so
that the ledges 22 can grip a backside 26 of the valve seat 24 to allow it to
be extracted.
[0034] A collar 30 may be threaded onto the upper end of the threaded shaft
12 to support
the threaded shaft 12 against a pancake hydraulic cylinder 32 allowing
substantial forces to be
applied to the seat puller 10 along axis 14 against a body of the valve or
pump casting 15.
[0035] Referring now to Fig. 2, each jaw 18 may attach to the other by
means of mutually
engaging hinge portions 34 extending toward each other from proximate inner
surfaces 38 of the
jaws 18. The hinge portions 34 hold the jaws 18 together to pivot with respect
to each other
about a transverse hinge axis perpendicular to axis 14 as retained by a hinge
pin (not shown in
Fig. 2).
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[0036] An upper end of each jaw 18 above the hinge portions 34 may provide
for a T-bar 36
generally sloping downward toward the inner surface 38 of each jaw 18.
[0037] Below the hinge portions 34 on the inner surface 38 of each jaw 18
is a blind bore
40that may receive corresponding ends of a helical compression spring (not
shown) urging the
bottom ends of the jaws 18 apart. This spring is optional. An upper surface of
the T-bar 36 of
each jaw 18 includes a circular indentation 42 which will interact with the
lower end of the
threaded shaft 12 (shown in Fig. 1) to lock the jaws 18 in the open position
as will be discussed
below.
[0038] Referring now to Fig. 3 the body 16 may include a threaded through
bore 46
threadably receiving a lower end of the threaded shaft 12 (shown in Fig. 1).
Transversely
extending downwardly-canted T-slots 48 slidably receive the T-bars 36 of the
jaws 18 shown in
Fig. 2 during the pivoting about the hinge portions 34. The T-slots 48 are
over sized to allow
pivoting action but have lower surfaces 50 that face upward to engage
corresponding lower
surfaces of the T-bars 36 biasing the T-bar 36 outward with upward force on
the T-bars 36 from
the body 16 and, accordingly, biasing the lower ends of the jaws 18 outward
with upward motion
of the body 16.
[0039] Referring now to Fig. 4, when the jaws 18a and 18 are assembled
together at the
hinge portions 34 by means of a threaded hinge pin 52, the installed
compression spring 54 urges
the lower ends of the jaws 18 outward. Beveled surfaces 56 on the outer lower
edges of the
ledges 22 of the jaws 18 engage comparable bevels on the valve seat 24 so that
downward force
on the body 16 by the threaded shaft 12 causes the lower ends of the jaws 18
to move inward as
shown in Fig. 5 to pass through the valve seat. As shown in Fig. 6, the spring
54 then urges the
jaws 18 apart so that the ledges 22 may overlap exposed back surfaces of the
valve seat 24
allowing the valve seat 24 to be pulled upward by force on the threaded shaft
12. Any such force
causes engagement between lower beveled surfaces of the T-bars 36 tending to
separate the
lower ends of the jaws 18. In addition, the threaded shaft 12 maybe threaded
downward through
the bore 46 of the body 16 to engage the flats 42 on the upper surfaces of the
T-bar 36 locking
the lower ends of the jaws 18 in their outermost position. At this point, as
shown in Fig. 7,
upward force on the threaded shaft 12 causes retraction of the valve seat for
removal.
[0040] Referring again to Fig. 1 it will be appreciated that the ability to
unscrew threaded
shaft 12 from the body 16 simplifies assembly of the puller 10 around the
hydraulic cylinder 32
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without the need to completely remove the collar 30. It will also be
appreciated that engagement
of the puller 10 with the valve seat 24 requires very little clearance beneath
the valve seat.
[0041] The components of the seat puller 10 may be fabricated from material
such as steel to
provide necessary strength for this operation.
[0042] Certain terminology is used herein for purposes of reference only,
and thus is not
intended to be limiting. For example, terms such as "upper", "lower", "above",
and "below" refer
to directions in the drawings to which reference is made. Terms such as
"front", "back", "rear",
"bottom" and "side", describe the orientation of portions of the component
within a consistent
but arbitrary frame of reference which is made clear by reference to the text
and the associated
drawings describing the component under discussion. Such terminology may
include the words
specifically mentioned above, derivatives thereof, and words of similar
import. Similarly, the
terms "first", "second" and other such numerical terms referring to structures
do not imply a
sequence or order unless clearly indicated by the context.
[0043] When introducing elements or features of the present disclosure and
the exemplary
embodiments, the articles "a", "an", "the" and "said" are intended to mean
that there are one or
more of such elements or features. The terms "comprising", "including" and
"having" are
intended to be inclusive and mean that there may be additional elements or
features other than
those specifically noted. It is further to be understood that the method
steps, processes, and
operations described herein are not to be construed as necessarily requiring
their performance in
the particular order discussed or illustrated, unless specifically identified
as an order of
performance. It is also to be understood that additional or alternative steps
may be employed.
[0044] It is specifically intended that the present invention not be
limited to the embodiments
and illustrations contained herein and the claims should be understood to
include modified forms
of those embodiments including portions of the embodiments and combinations of
elements of
different embodiments as come within the scope of the following claims.
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