U.S. patent application number 10/832517 was filed with the patent office on 2005-03-17 for plunger with flow passage and chamber.
Invention is credited to Gray, William R., Holt, James H..
Application Number | 20050056416 10/832517 |
Document ID | / |
Family ID | 46302007 |
Filed Date | 2005-03-17 |
United States Patent
Application |
20050056416 |
Kind Code |
A1 |
Gray, William R. ; et
al. |
March 17, 2005 |
Plunger with flow passage and chamber
Abstract
A chamber for use in plungers used in wells that produce liquids
and/or gases under, which is connected to an internal flow passage
to facilitate more rapid descent of the plunger to the well stop. A
closure means is housed within the chamber, and is in the open
position when the plunger descends down the tubulars. The closure
means is actuated when the plunger and stopper stem reach the well
stop. Once the closure means is seated, it is held in the closed
position by the build up of pressure below the plunger. The
invention also covers a plunger and a method of using the
plunger.
Inventors: |
Gray, William R.;
(Huntsville, TX) ; Holt, James H.; (Conroe,
TX) |
Correspondence
Address: |
THE MATTHEWS FIRM
2000 BERING DRIVE
SUITE 700
HOUSTON
TX
77057
US
|
Family ID: |
46302007 |
Appl. No.: |
10/832517 |
Filed: |
April 27, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10832517 |
Apr 27, 2004 |
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10077457 |
Feb 15, 2002 |
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6725916 |
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Current U.S.
Class: |
166/68.5 ;
166/101; 166/106; 166/110 |
Current CPC
Class: |
E21B 43/121
20130101 |
Class at
Publication: |
166/068.5 ;
166/101; 166/110; 166/106 |
International
Class: |
E21B 043/00; E21B
033/12 |
Claims
We claim:
1. A plunger for use in a gas/liquid lift system in downhole
production tubulars in a well producing fluids and/or gases under
variable well pressures, comprising: a body slidingly engageable
within the tubulars and capable of movement up and down said
tubulars; said body having a top end, a bottom end, and an inner
passage within said body for receiving well fluids and/or gases and
enabling more rapid descent of said plunger in a well; a chamber in
said body, wherein said body provides a wall at least partially
surrounding said chamber, wherein said chamber is capable of
receiving well fluids and/or gases; an opening between the chamber
and the inner passage that allows fluid communication between the
chamber and the inner passage; a closure member at least partially
located inside the chamber, the closure member having a top end and
a bottom end, said member being moveable between an open and a
closed position; and at least one port through said wall, wherein
well fluids and/or gases can flow into said chamber and into said
inner passage.
2. The plunger of claim 1, further comprising at least one opening
near or at the top of said plunger, wherein said fluids and/or gas
can exit out of the inner passage.
3. The plunger of claim 1, wherein the closure member is a stopper,
and wherein said stopper has a heat, a top end, and a bottom end
with a stem attached thereto.
4. The plunger of claim 1, having a plurality of ports in side
walls of the plunger, the ports opening into the chamber, said
ports allowing well fluids and/or gases to enter or exit the
chamber.
5. The plunger of claim 3, further comprising a roof within said
chamber, and an opening in the roof, wherein a portion of the
stopper rests against said roof opening in the closed position,
thereby closing the opening between the chamber and the inner
passage, thereby obstructing a flow of well fluids and/or gases
into the inner passage.
6. The plunger of claim 3, having a chamber with a roof and a
floor, wherein said floor is parallel to the roof.
7. The plunger of claim 3, having a stopper with a triangular
head.
8. The plunger of claim 3, having a chamber with a floor and a
roof, wherein said roof is dome shaped, and said floor is
nonparallel to said roof.
9. The plunger of claim 3, having a stopper with a semicircular
head.
10. The plunger of claim 1, further comprising a fishing part
attached to the top end of said plunger, the fishing part having an
inner passage for the flow of fluids and/or gases.
11. The plunger of claim 1, further comprising an opening within
the floor of the chamber, wherein said bottom end of said closure
member rests against the chamber floor in the open position and a
stem attached to the bottom end of said closure member, said stem
extending downwardly through said opening.
12. The plunger of claim 11, wherein said stem engages a well stop
when the plunger descends to the well stop, thereby pushing the
stem and the closure member upward, the head of the closure member
closing the opening between the chamber and the inner passage,
thereby obstructing a flow of well fluids and/or gases into the
inner passage, said closure member being held against the roof by a
build up of pressure below the closure member.
13. The plunger of claim 1, wherein the outlet openings of said at
least one port opens into the chamber above the top end of the
closure member when the closure member is in the open position and
below the bottom end of the closure member when the closure member
is in the closed position.
14. The plunger of claim 4, having an inlet in the wall of the
chamber that leads to said at least one port that opens into said
chamber, wherein the inlet of said port is oblong in shape.
15. The plunger of claim 1, wherein at least a portion of the
plunger body has a plurality of spirals thereon.
16. The plunger of claim 1, wherein at least a portion of the
plunger body has a brush disposed thereon.
17. The plunger of claim 1, wherein a portion of the body of the
plunger body has plurality of washers thereon, said washers being
movable about said body.
18. The plunger of claim 1, having a least one external pad
disposed about a portion of said plunger body.
19. The plunger of claim 1, wherein at least a portion of the body
of the plunger is coated with a compound that reduces friction
between the plunger and the tubulars.
20. A chamber for use in gas lift plungers, comprising: an cap for
attachment to a gas lift plunger body, said cap having an inner
passage and a chamber for receiving well liquids and/or gases, said
chamber having a roof at the upper end and a floor at the lower
end, with an opening in said roof that allows fluid communication
with an inner passage in a plunger; and wherein a plunger stopper
is at least partially located inside the chamber, the plunger
stopper being moveable between an open and a closed position.
21. The chamber of claim 20, having at least one port in said wall
for the entry of well liquids and/or gases into the chamber, said
at least one port having an inlet opening in the plunger body and
an outlet opening in the walls of the chamber, with a passage
between the inlet and the outlet, wherein the outlet openings of
said port is positioned in the chamber above the top end of the
stopper when the stopper is in the open position and below the
bottom end of the stopper when the stopper is in the closed
position.
22. The chamber of claim 20, further comprising an opening in the
floor that communicates with a bore below the floor, said bore
extending downward and having an opening at the bottom of said
cap.
23. The chamber of claim 20, the stopper has a head, the head
having an upper end and a lower end, the upper end of the head
resting against the roof in the closed position, the lower end
having a stem attached thereto, and resting against the chamber
floor in the open position and the stem extending downwardly
through said opening in the floor and into said bore and extending
outwardly from said bottom end opening, whereby the stem engages a
well stop when the plunger descends down the well tubulars thereby
pushing the stopper stem and the head upward, at least a portion of
the head being seated against the roof to close the opening between
the chamber and the inner passage, thereby obstructing a flow of
well liquids and/or gases into the inner passage, said stopper
being held against the roof by a build up of pressure below the
stopper.
24. The chamber of claim 20, wherein said cap is securably or
removably attached to said plunger body.
25. The chamber of claim 20, used in a plunger wherein at least a
portion of the plunger body has a plurality of spirals thereon.
26. The chamber of claim 20, used in a plunger wherein at least a
portion of the plunger body has a brush disposed thereon.
27. The chamber of claim 20, used in a plunger wherein a portion of
the body of the plunger body has plurality of washers thereon, said
washers being movable about said body.
28. The chamber of claim 20, used in a plunger having a least one
external pad disposed about a portion of said plunger body.
29. The chamber of claim 20, used in a plunger body wherein at
least a portion of the plunger body is coated with a compound that
reduces friction.
30. The chamber of claim 20, wherein said chamber has a roof that
is parallel to said floor.
31. The plunger of claim 20, wherein said chamber has a roof that
is nonparallel to said floor.
32. A method of lifting well liquids and/or gases from a
subterranean reservoir to a well surface in tubulars in a well by
increasing pressure in the well tubulars, comprising: providing a
plunger with a body that is capable of movement up and down said
tubulars, said body having a top end, a bottom end, and an inner
passage within said body for receiving well fluids and/or gases and
enabling more rapid descent in a well; making a chamber within said
plunger body for receiving well fluids and/or gases, with an
opening that communicates with the inner passage and wherein well
liquids and/or gases can flow into said chamber and into said inner
passage, wherein said body provides at least one side wall at least
partially surrounding said chamber; placing a stopper at least
partially inside the chamber, the stopper being moveable between an
open and a closed position; positioning the closure means in the
open position; putting said plunger in a well having tubulars that
produces fluids and/or gases; and allowing said plunger to descend
or gravitate to the well bottom or well stop.
33. The method of claim 32, further comprising step of attaching a
stem to the stopper and positioning the stopper so that the stem
extends outside the bottom of said plunger body, wherein said stem
contacts said well bottom or well stop when said plunger gravitates
down said tubulars, thereby pushing said stopper upwardly to close
said opening to said inner passage.
34. The method of claim 33, further comprising steps of: allowing
pressure to build up in the well to a predetermined or desired
level and enabling fluids from a reservoir to accumulate in the
well; and opening a valve connected to the tubulars that decreases
the pressure inside the tubulars thereby elevating the plunger and
the accumulated well fluids and/or gases to the surface.
35. The method of claim 32, further comprising the step of
attaching a fishing part to the top end, said fishing part having
an inner passage for the flow of fluids and/or gases.
36. The method of claim 32, further comprising the step of placing
a plurality of ports disposed in side walls of the fishing part,
the ports having an inlet opening in the walls of the inner passage
and an outlet opening in the fishing part, said ports allowing well
fluids and/or gases to exit the inner passage when the stopper is
in the open position.
37. The method of claim 32, further comprising the step of
providing a plurality of ports in the chamber wall, said ports
allowing well fluids and/or gases to enter or exit the chamber.
38. The method of claim 32, wherein the flow of said liquids and/or
gases into said chamber is greater than the flow of said liquids
and/or gases into the inner passage, thereby creating a choking
effect.
39. The method of claim 38, wherein the choking effect assists in
keep the stopper in the open position.
40. The method of claim 32, further comprising steps of: placing
the plunger in the tubulars without shutting in the well; and
allowing the plunger to ascend to the well surface when sufficient
pressure has built up in the well.
Description
RELATED APPLICATIONS
[0001] This application is a continuation in part of U.S.
application Ser. No. 10/077,457, filed Feb. 15, 2002, that is still
pending.
FIELD OF THE INVENTION
[0002] The present invention relates to improvements in plungers
used in a gas/fluid lift system in wells producing both fluids and
gases, such as petroleum and natural gas, under variable pressure
to facilitate the lifting of fluids from a subterranean reservoir
to the surface through a well conduit or tubulars.
[0003] Another further improvement concerns a valve-like assembly
used to regulate and restrict the flow of fluids and gases through
an internal passage in plunger that allows such plungers to descend
to the well bottom more rapidly than plungers without internal
passages.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] Details of this invention are described in connection with
the accompanying drawings that bear similar reference numerals in
which:
[0005] FIG. 1 is a schematic representation of an operating well
and production of the well by utilizing a gas operated plunger
according to an embodiment of the invention;
[0006] FIG. 1A shows an embodiment of plunger according to this
invention that is descending in the production tubulars and has the
closure member in the open position;
[0007] FIG. 1B shows an embodiment of plunger according to this
invention in the production tubulars, with the closure member in
the closed position;
[0008] FIG. 1 is a schematic representation of an operating well
and production of the well by utilizing a gas operated plunger
according to an embodiment of the invention;
[0009] FIG. 2 is a longitudinal, external view, of a gas operated
plunger;
[0010] FIG. 3 is a top inner perspective view of the four segments
of the embodiment of FIG. 2;
[0011] FIG. 4 is an inner, perspective view of the grooved core and
jacket assembly of the segments of FIGS. 2-3, with one of the
segments removed;
[0012] FIG. 5 is a longitudinal view of two of the four cooperating
segments that form the jacket assembly for use with the preferred
embodiment of FIG. 18;
[0013] FIG. 6 is a view of the upper end of the four segments of
FIG. 5;
[0014] FIG. 7 is an inner, perspective view of one of the segments
of FIGS. 5-6;
[0015] FIG. 8 is an outer perspective view of one of the segments
of FIGS. 5-6;
[0016] FIG. 9 is an inner planar, or flattened, perspective view of
one of the segments of FIGS. 5-7;
[0017] FIG. 10 is an outer planar, or flattened, perspective view
of one of the segments of FIGS. 5-6, 8;
[0018] FIG. 11 is a cross-sectional view of the segments of FIGS.
6, 9, taken across lines D-D of FIG. 9;
[0019] FIG. 12 is a cross-sectional view of the segments of FIGS.
6, 9, taken across lines A-A of FIG. 9;
[0020] FIG. 13 is a cross-sectional view of the segments of FIGS.
8, 10, taken across lines C-C of FIG. 10;
[0021] FIG. 14 is a cross-sectional view of the four segments of
FIGS. 5, 6, taken across lines B-B of FIG. 10;
[0022] FIG. 15 is a cross-sectional view of the segments of FIGS.
8, 10, taken across lines B-B of FIG. 10;
[0023] FIG. 16 is a detailed drawing, partially in section,
illustrating the biasing means of the preferred embodiment of FIG.
18, and the sectional view of the grooves and segments of FIGS. 9,
12;
[0024] FIG. 17 is a detailed drawing, partially in section,
illustrating the flow in the area between the segments and grooves
in FIG. 16 of the preferred embodiment of FIG. 18;
[0025] FIG. 18 is a longitudinal view, in quarter section, of a
preferred embodiment of a gas operated plunger;
[0026] FIG. 19 is an outer perspective view of the installation of
one of the segments underneath a retaining ring;
[0027] FIG. 20 is a longitudinal view, in quarter section, of a gas
operated plunger that has a chamber and an internal passage and
valve closure means in the open position;
[0028] FIG. 21 is the top view of the fishing piece of the plunger
of FIG. 20;
[0029] FIG. 22 is the bottom view of the plunger of FIG. 24;
[0030] FIG. 23 is a sectional view of the chamber of the plunger of
FIG. 20 with the closure means in the closed position;
[0031] FIG. 24 is a sectional view of the chamber of an alternate
embodiment of a plunger and a plunger stopper in the open
position;
[0032] FIG. 25 is a sectional view of the chamber of an alternate
embodiment of a plunger and a plunger stopper in the closed
position;
[0033] FIG. 26 is a longitudinal cross-sectional view of a spiral
plunger;
[0034] FIG. 27 is a longitudinal cross-sectional view of a spiral
plunger;
[0035] FIG. 28 is a longitudinal cross-sectional view of a spiral
plunger;
[0036] FIG. 29 is a longitudinal cross-sectional view of a spiral
plunger;
[0037] FIG. 30 is a longitudinal cross-sectional view of a spiral
plunger;
[0038] FIG. 31 is a longitudinal cross-sectional view of a Teflon
coated plunger;
[0039] FIG. 32 is an external view of plunger with pads;
[0040] FIG. 33 is an external view of a brush plunger;
[0041] FIG. 34 is an external view of a plunger with washers;
[0042] FIG. 35 is a is a longitudinal cross-sectional view of a
plunger with a grooved mandrel and pads with fingers;
[0043] FIG. 36 is a is a longitudinal cross-sectional view of a
plunger with pads;
[0044] FIG. 37 is a longitudinal cross-section view of a spiral
plunger with an internal fishing piece in the closed position;
[0045] FIG. 38 is a longitudinal cross-sectional view of a spiral
plunger with an internal fishing piece in the open position;
and
[0046] FIG. 39 is a top cross-sectional view of the chamber of
FIGS. 37-38.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0047] The present invention provides a plunger for use in tubulars
in wells producing both liquids and gases under variable pressure.
The plunger assists with the build up of pressure between the
subterranean reservoir and the surface by having an inner seal and
an external sliding and variable holding seal with adjacent well
tubulars. The inner and external seals restrict the upward flow of
the liquids and/or gases. This causes an increase in the well
pressure below the plunger and facilitates the upward lifting of
the plunger and gases and/or liquids from the reservoir to the
surface when pressure is reduced above the plunger, such as at the
well head.
[0048] The improved plunger comprises a body which is slidingly
engageable and which gravitates within the tubulars. The plunger
body may have an external sealing means such as a plurality of
segments which are mounted around a core, also known as a mandrel,
and which collectively form a jacket. The segments, collectively
the jacket assembly, are slidingly and sealingly engageable with
the insides of the well tubulars, based upon the pressure affected
between the inner surface, or inside, of the jacket and the core.
The jacket has the largest diameter of the plunger when the
segments are in an expanded radial position. The segments have a
convex outer surface and typically have a concave inner surface.
However, the core of the plunger could be square, triangular, or of
another geometric shape, in which case the inner surfaces of the
segments could be flat, or of any other corresponding geometric
shape.
[0049] In an embodiment of the plunger, there is also an inner
sealing means such as at least one rigid finger which projects
radially inward from the underside of each segment toward the core,
with the fingers of the adjacent segments collectively cooperating
to encircle the core. Preferably, there are a plurality of fingers
on the undersides of each segment. The fingers are normally
separated from the core especially when the segments, collectively
the jacket, are pushed radially outward. When the fingers are
separated from the core, the fingers collectively create a tortuous
path of flow between the core and the segment undersides and affect
a turbulent inner seal. When the segments making up the jacket are
pushed to their most radially inward position, the fingers touch
the core and cause a complete inner seal.
[0050] In a further embodiment, the core has at least one
circumferential groove on its surface, and more preferably a
plurality of grooves. This also creates a tortuous path of flow
between the core and the jacket underside and affects an inner
seal. In another embodiment, the plunger has both grooves and
fingers, and the fingers are correspondingly located to fit into
the grooved portions of the core. This design creates an even more
tortuous path of flow for liquids and gases which effects an inner
seal and creates an increased surface area between the segments and
core. The increased surface area also has the effect of increasing
the internal plunger pressure, i.e., the pressure between the core
and the jacket assembly and energizes the segments, pushing the
segments radially outward toward the well tubulars. This preferred
design also prevents detachment and/or loss of the segments if the
retainer rings, explained below, fail because the segments will be
held in place by the finger-groove interface and by the outer well
tubulars. This design provides for increased functionality and
seeks to minimize expensive and time consuming fishing operations
to retrieve dislocated parts.
[0051] In a plunger that has external pads, there is at least one
biasing means, which is typically a spring, between the underside
of each segment and the core to outwardly bias each segment and to
achieve inward and outward radial rebounding of the segments from
the inner core. The preferred embodiment also has recessed spaces,
or blind holes, in the core or core grooves and/or the fingers that
hold the biasing means in place between the core and segments and
prevent displacement and loss of the biasing means. The preferred
embodiment typically also has retaining means such as retaining
rings that limit the outward radial movement of the segments/jacket
assembly. In plungers with both fingers and grooves, at least one
of the outside edges of the grooves will be angularly reduced to
allow installation of segments with projecting fingers into the
grooves of the core and allows the end of the segments to be
installed underneath the retaining rings.
[0052] In yet another embodiment of the invention, the plunger has
an internal passage that extends part way through the body, or
through the entire axis of the plunger, to facilitate a more rapid
descent of the plunger to the bottom of the well or the well stop
means. These plungers may further have a chamber in a modified end
cap near the bottom end, which houses a closure means such as a
plunger stopper. The chamber connects to the internal passage at
the roof and connects to the stem bore in the floor of the chamber.
These plungers also have a top end and a bottom end with at least
one opening at or near the top and the bottom end and may have at
least one port that allows the flow of the well contents. The
chamber into the chamber connects to the flow passage to increase
the flow rate and to facilitate even more rapid descent of the
plunger. The preferred embodiment has a plurality of ports within
the chamber, and may have additional ports near the top end.
[0053] The plunger stopper has a top end that has a shape similar
to that of the roof, and in some cases, the upper chamber area, and
has a stem attached to the bottom end that extends downward through
and protrudes outwardly from an opening in the bottom end. When the
stem engages the bottom well stop means upon descent, the closure
means such as a stopper, is pushed upwardly against the roof of the
chamber, thereby sealing off the inner passage and restricting the
upward flow of liquids and/or gases from the chamber and the ports
in order to build up pressure below the plunger.
[0054] The improved design of this closure means, or stopper,
operates without springs or catches, yet still holds the stopper
against the roof of the chamber. It also does not use long sucker
rod, which are prone to bending, to unseat the closure means.
Instead, the pressure build-up below the plunger keeps the plunger
stopper engaged against the roof of the chamber. The plunger stays
at or near the bottom well stop until the pressure in the tubulars
above the plunger is reduced, or until the pressure below the
plunger exceeds the pressure above the plunger. The simplified bore
sealing means also reduces the amount of time needed for costly and
time-consuming repairs and replacements and dispenses with the need
for expensive and customized devices at the surface that unseat the
prior art closure valves.
[0055] Referring first to FIG. 1, there is shown a well W for
producing hydrocarbon gases and/or liquids from a subterranean
reservoir R. The well may be of the horizontal or vertical variety.
The plunger pump P is especially useful in wells where the gas
pressure alone is insufficient to produce the flow of liquids or
the significant flow of liquids at the surface. In these
situations, hydrocarbons from such wells cannot be recovered except
through the installation of considerably expensive submersible pump
units that require daily inspection and maintenance. Similarly, in
wells producing primarily gas, the gas production may be
substantially impaired by liquids, whether hydrocarbons or salt
water, which accumulate in the bottom of the well. In either event,
it is desirable to remove liquids from the bottom of such wells
without installing conventional pumping units. Typically, one or
more well conduits extend from the subterranean reservoir R to the
well surface WS. In the preferred embodiment, there is a casing
string CS, at the upper end of which is a well head WH, and a
tubular string T, also known as "tubulars." Tubulars T is a generic
term used to define the variety of tubes and tubular members, such
as cement casings, conduits, and tubing and tubing string, which
can also be referred to as the production string, which can be made
from a variety of materials such as plastic, metal, and concrete.
Tubulars line the well surface and can also be placed inside or on
the outside of other tubulars. In any event, the tubulars are the
well channels through which liquids from the subterranean reservoir
R are raised to the surface. Near the bottom of the tubulars is a
tubing stop means TS mounted in any suitable manner. The tubing
stop means TS may be relocated by wire line or other operations at
different depths as well conditions change. The tubing stop TS
preferably incorporates a bumper spring B of some type for stopping
downward movement of a plunger type pump unit P, which is slidably
and sealably disposed in the tubulars T and which will be described
in greater detail hereafter. At the well surface WS is a master
cutoff or motor operated valve MV suitably attached to the tubing
string T to entirely block the flow of gases and/or liquids from
the tubulars T as desired. This arrangement further allows
retrieval of the plunger pump P for inspection or repair. Above the
valve V is a flow tee F and a lubricator L closed at its upper end
by detachable end cap E. A bumper sub BS is usually placed therein
with a spring (not shown) which is engageable by the plunger pump P
when rising through the tubulars T to stop movement of the plunger
P and to cushion the shock created thereby. Connected to the flow
tee F is a production or pay line PL in which is installed a motor
control valve MV. An electronic controller EC is provided for
operating the control motor valve MV. The electronic controller EC
is also connected to a tubing plunger sensor S for sensing the
pressure within the wellhead WH. A plunger catching device PC may
also be attached to the tubing string T above valve V. While not
required, a rod could be used to unseat the closure means.
[0056] Initially, the plunger P is placed in the tubulars through
the lubricator sub L. This is done by removing the cap E while the
valve V is closed. Then the cap E is replaced, the valve V opened,
and the plunger P is allowed to gravitate or fall to the bottom of
the well through the tubulars T. Although the sealing means, such
as a jacket 100 made of segments, e.g., 46, 47, 48, 49, is biased
outwardly for sliding and sealing engagement with the interior of
the tubulars T, there is a small amount of leakage around the
outside of the jacket assembly 100 and through the edges of the
sealing segments 46, 47, 48, 49. This permits the plunger P to fall
under its own weight toward the bumper spring B that will arrest
its downward movement. Other plungers of this invention that do not
have a jacket, fall under their own weight. When this occurs, the
motor valve MV is closed and a time sequence is initiated by the
controller EC. Additional gases and/or liquids enter the tubulars T
and the gas and/or fluid pressure begins to build. The controller
EC is programmed to keep the valve V closed until substantial
liquids have entered the tubulars T and sufficient gas pressure has
built up within the well. The amount of time necessary will be
different for every well and may change over the life of the well.
After a predetermined amount of time, the controller EC opens the
motor valve MV, which substantially reduces the pressure above the
plunger P. Consequently, the accumulated gas pressure therebelow
forces the plunger P, and the gases and/or liquids trapped
thereabove, upwardly through the conduit or tubulars T, through the
flow tee F, the valve V and the pay line PL for production of the
well. As the plunger P is propelled upwardly through the tubulars T
by pressure, it passes through the valve V, and is sensed by the
sensor S and eventually movement thereof is arrested by a spring
(not shown) in the lubricator sub L. When the plunger P is detected
by the sensor S, a signal is transmitted to the controller EC that
initiates closure of the valve V. Thereafter the plunger P is
allowed to again gravitate or fall to the bottom of the well so
that this cycle can be repeated.
[0057] However in wells that have very low pressures, the well need
not be shut in (by closing the valve V) to allow the plunger to
descend down the tubulars. This allows for a near continuous
production. Additionally, in plungers with large diameter flow
passages, such as 1 inch in diameter or greater, the plunger may
also be able to descend down the tubulars without shutting in the
well. Once sufficient pressure builds beneath the plunger, the
plunger and the contents of the tubulars will be brought to the
well surface.
[0058] In describing the specific embodiments herein which were
chosen to illustrate the invention, certain terminology is used
which will be recognized as employed for convenience and having no
limiting significance. For example, the terms "upper," "lower,"
"top," "middle," "bottom," and "side" refer to the illustrated
embodiment in its normal position of use. The terms "outward" and
"inward" will refer to radial directions with reference to the
central axis of the device. Furthermore, all of the terminology
defined herein includes derivatives of the word specifically
mentioned and words of similar import.
[0059] Differential gas pressure operated pistons, also known as
plungers, have been used in producing subterranean wells where the
natural well pressure is insufficient to produce a free flow of
gas, and especially liquids, to the well surface. A plunger lift
system typically includes tubulars placed inside the well conduit,
which extend from the reservoir(s) of the well to the surface. The
tubulars have a well valve and lubricator at the top and a tubing
stop and often a bumper spring or other type of spring assembly at
the bottom. The cylindrical plunger typically travels between the
bottom well stop and the top of the tubulars. The well is shut in
for a selected time period that allows pressures to build up, then
the well is opened for a selected period of time. When the well
valve is opened, the plunger is able to move up the tubulars,
pushing a liquid slug to the well surface. When the well valve is
later closed, the plunger, aided by gravity, falls downwardly to
the bottom of the tubulars. Typically, the open and closed times
for the well valve are managed by a programmable electronic
controller.
[0060] When the plunger is functioning properly, liquids accumulate
and stay above the plunger and pressurized gases and/or liquids
below the plunger are blocked from flowing up, around, and through
the plunger. As a result, the plunger and accumulated liquids are
pushed upwardly.
[0061] The improved stopper assembly that is housed in a chamber is
typically located in a modified end cap and seals off the inner
passage in a simplified manner. The stopper stem and stopper head
is pushed up into the chamber when the plunger bottom contacts the
well stop means, and the stopper is held up against the opening of
the passage by the fluid and/or gas pressure below the plunger.
[0062] FIG. 1A shows an embodiment of plunger according to this
invention that is descending in the production tubulars T, with the
closure member 600 in the open position. The fluids 912 in the
tubulars are able to enter the chamber 510 through the ports 701,
702 and flow into the inner passage 460 and out an opening 720 in
the top of the plunger body. Of course the opening may be near
located elsewhere, near the top.
[0063] FIG. 1B shows an embodiment of plunger according to this
invention in the production tubulars T, with the closure member in
the closed position. The fluids 912 in the tubulars are still able
to enter the chamber 510 through the ports 701, 702 and flow into
the chamber below the closure member, but cannot exit through the
inner passage 460 as the closure member has closed off the
communication 525 between the chamber and the inner passage.
[0064] This simplified and improved design dispenses with the need
for complicated moving parts which to actuate the closure means,
and eliminates the need for expensive equipment at the well head
which is used to unseat the closure means.
[0065] Referring now also to FIGS. 2-25, the drawings show a
plunger, which is used in a gas/fluid lift system in the tubulars T
of wells that produce both liquids and gases under variable
pressure. Referring now to the drawings in detail, FIGS. 1, 2, 18,
and 20 show a plunger that has a body that is slidingly engageable
within the well tubulars T. The body is typically made of rigid
material, such as arty type of metal or metal alloys, rigid
plastics and polymers, ceramics, and the like, with the preferred
embodiment being made of stainless steel. In an embodiment, the
body has an inner core 10, for support and for inner sealing. The
core 10 may also be known as a mandrel, and may be solid or hollow.
The core is typically substantially cylindrical and typically has
the smallest diameter of the plunger body.
[0066] As in FIG. 2, there is a flexible jacket assembly 100
surrounding or mounted about the core 10. The preferred embodiment
has four segments 20, 21, 22, and 23, which collectively form a
flexible jacket assembly 100. Of course, fewer or more segments can
be used to form the jacket assembly. These segments 20, 21, 22, and
23, are made of a relatively rigid material, such as those known in
the art, like metal, hard rubber, plastic, graphite, etc., and
typically have a relatively smooth outer surface, due to the die
cast molding of the segments, and/or polishing of the segments, for
sliding and sealing contact with the walls of the well tubulars in
which the plunger P is to be used, such as the inner walls of the
tubulars T in FIG. 1. Referring now to FIGS. 2, 3 and 4, each
segment typically has a substantially convex outer shape 30 and a
substantially concave inner surface 32, like that of a semicircular
arch. In an embodiment, each segment 20-23, or 46-49 (see e.g.,
FIGS. 5-8 and 35-36) has substantially the same width and curve so
that several segments can be placed side by side to form a flexible
jacket assembly 100, which is mounted around the core 10, such as
by upper and lower retaining rings 150 and 160, respectively. The
retaining rings 150, 160, limit the outward radial movement of the
jacket assembly, and may be secured by one or more set screws 415.
The inner surface of the jacket assembly 100 is separated from the
core 10, unless it is pushed to its most inward position.
[0067] The sealing segments 20, 21, 22, 23, which collectively make
up the jacket assembly 100, are typically held in position around
the core 10 of the plunger body by retaining means such as an upper
retaining ring 150 and a lower retaining ring 160, which slip on
over the core 10, with the upper retaining ring usually abutting
the collar 410 of a fishing part 420. As in FIG. 19, the top end
400 of the core 10 is also typically substantially cylindrical and
has means such as threading, i.e., a helical or spiral ridge which
can be used to removably or securably attach, by screwing, into or
onto another part. Alternatively, there may be drilled or threaded
holes in both the plunger body and the part, to be secured other
parts of the plunger may be connected by threads, welding,
soldering, pins, screws or a combination thereof. Other parts
include plunger parts, plunger accessories, or other oil field
components or tools.
[0068] The preferred embodiment has a upper end fishing piece 420
which is typically threadingly connected 430 near the top end of
the core 400 and has a head 425 located above a fishing neck 424 of
a reduced diameter that is removably attached to the top end 400
and may also be secured with a set screw, e.g., 415. The fishing
piece 420 may also have a wrench flat 423, to assist in loosening
or tightening. Alternatively, the fishing piece or part 420 may be
tooled into the core 10. The lower retaining ring usually abuts an
end cap 140. The bottom end 426 of the core 10 typically has means
such as threading 435 to attach other parts. In the embodiment of
FIG. 18, a plug or end piece 140 is threadedly connected to
corresponding threads 435 on the lower end of the core 10, and may
have a tapered end 141. The cap may be provided with wrench flats
142 for aiding in the engagement or disengagement of the threaded
connection, and a set screw (not shown) may be tightened when the
cap is fully engaged as to prevent accidental loosening or
disengagement. Alternatively, the end cap 140 may be tooled into
the bottom end 426 of the core 10.
[0069] The upper and lower ends of each of the segments may also
have notches across the ends as in 21c, 23c, or recessed ends such
as in 21d, 23d, which cooperate to fit under the retaining rings
150, 160. This limits the movement of the jacket assembly 100
radially inwardly and outwardly from the core 10. The upper and
lower ends of the segments may also be inwardly tapered as in 20a,
21a, 22a, 23a, so that when the segments engage a restriction in
the well tubulars T, the segments will be forced toward their most
inward position. This allows the plunger to overcome the
restriction and to pass through the restricted area. In their
innermost position 290, the segments, e.g., 20-23 and 46-49, have a
diameter less than that of any restriction to be encountered in the
tubulars. Referring now to FIGS. 1 and 2, the jacket assembly also
has the largest diameter 300 of the plunger when the jacket
assembly 100 is in its most radially expanded position 300, when it
sealingly engages the tubulars. Referring now to FIGS. 1, 3, and 4,
the jacket assembly 100 is also slidingly and sealingly engageable
within the well tubulars T, based upon the pressure effected by the
flow path 200 between the underside of the jacket 100 and the core
10 by the gas and liquids that move upwardly between the segments
20, 21, 22, and 23, and based upon the outward biasing force of the
jacket assembly against the tubulars T.
[0070] Typically, the segments are substantially rectangular 25.
However, the segments 20, 21, 22, 23, and 46, 47, 48, 49, may be a
variety of geometric shapes, sizes, and dimensions, as long as they
are able to cooperate to surround the core or to form a jacket
assembly 100. One such variation of segments 46, 47, 48, 49 of the
preferred embodiment are shown in FIGS. 5, 7-15, 18, 20, and 35.
One of the segments 48 is in inner and outer perspective views in
FIGS. 5, 7, 8, 9, and 10, and cross-section in FIGS. 11, 12, 13,
and 15. FIG. 6 is an upper end view of the segments 46-49. FIG. 14
is a sectional view of the segments 46-49 at section B-B, in their
most inward position. Each of these segments 46, 47, 48, 49, is
provided with a convex, or substantially convex outer surface, 51,
52, 53, 54, respectively. The inner surfaces of the segments are
substantially cylindrical in shape, e.g., 46a, 47a, 48a, 49a. The
segments of the preferred embodiment further have sides which have
a tab 60 or slotted 61, 67 portion, preferably with a tab 60 on one
side and a slot 61, 67 on the opposing side, as in FIGS. 5, 7, and
8. For example in FIG. 5, segment 48 has a tab 60 that is engaged
with slot 61 of segment 49. See also segments 46 and 47 in FIG. 14,
with tabs 64, 66, respectively and slots 63, 65, respectively. The
cross-section of segments 46, 47, 48, 49, as in FIG. 14, show that
when the mutually engageable tabs 60, 62, 64, 66 are interconnected
with the slots 61, 63, 65, 67 located on the sides of the adjacent
segments, that a circumferential jacket assembly 100 is formed. In
FIGS. 6, 8, and 9, these tabs, e.g., 60, and slots, e.g., 67, have
stepped areas so that a portion of a tab 60a overlaps an inset
portion of a corresponding slot 67a, 67b. The overlapping is
accomplished with opposing surfaces, e.g., 67a and 60a, which are
slidably engageable with the opposing surfaces of the adjacent
segments 46-49, and which guide the segments inwardly and outwardly
between their innermost and outermost radial positions. These
overlapping, opposing, sealing surfaces are planar surfaces which
are tangentially disposed relative to a cylinder whose axis
corresponds with the axis of the core 100 of the plunger body about
which the segments are disposed. The overlapping surfaces further
minimize leakage from the flow path 200 of FIGS. 16, 17, between
the core and the segments, and therefore assist in inner
sealing.
[0071] The upper and lower ends of these segments may also be
inwardly tapered as at 51a, 52a, 53a, 54a, and 51b, 52b, 53b, 54b,
respectively, so that when the segments engage a restriction in the
well tubulars, the segments will be forced inwardly to allow the
plunger to pass through the restriction. In the preferred
embodiment, the upper ends of each segment have a semicircular
notch 70, 72, 74, 76, as do the lower ends of such segments 71, 73,
75, 77, which slidably fit under the lugs, e.g., 153, 163, 164 of
the retaining rings. See FIGS. 18, 19.
[0072] The preferred embodiment further has segments wherein the
inner surface or underside, e.g., FIG. 7, 16, possess at least one
finger 120 which is preferably made of rigid material, such as
metal, stainless steel, plastic, hard rubber, graphite, and the
like. The rigid fingers 120 of the exemplary embodiment are made of
metal and are an integral part of the segment 46, 47, 48, 49, which
is molded. The exemplary embodiment has three fingers 120 on the
underside of each segment. See, for example, FIG. 7. Preferably,
there is a plurality of rigid fingers on each segment underside,
with the preferred embodiment, e.g., FIGS. 4, 7, 19, having three
such fingers 120 on the underside of each segment 32, 63,
respectively. The fingers 120 of each segment protrude radially
inward toward the core 10 and are parallel and horizontally aligned
with the fingers 120 of the adjacent segments to collectively
cooperate to encircle the core 10, and serve as part of the
internal sealing means. The fingers 120 and core 10 are typically
separated by space, or a flow path 200 unless the fingers are
pushed to their most inward position. If the core 10 also has
grooves, e.g., 12, 14, 16, the fingers 120 on the underside of the
segments 46, 47, 48, 49 are adjacent to and aligned with the
grooves 12, 14, 16, and the fingers 120 fit into the grooves, 12,
14, 16. See FIGS. 3, 19. Where both fingers and grooves are
present, there is an increased surface area between the inner
surface of the segments and the core, which energizes the segments
and pushes the segments outwardly to cause an external seal with
the tubulars. Typically during operation, the fingers 120 and core
10 or core grooves 12, 14, 16, are separated by a space, or flow
path 200.
[0073] As in FIGS. 3, 7, 13, each finger 120 is defined by top 120f
and bottom side surfaces 120b. The fingers 120 may be in a variety
of geometric shapes. For example, the fingers 120 may have a
cross-section such as that of a V-shape, wherein the top and bottom
sides converge (not shown), or conversely the side surfaces may
diverge with respect to one another (not shown). In the preferred
embodiment, the fingers 120 also have an inner surface 120d, which
is a curved concave shape, which is complimentary to the shape of
the core 10. However, the inner surface of the finger 120 could
also be semicircular in cross-section, with a convex inner surface
(not shown). Many other variations and combinations thereof are
also possible. Further, the finger has first 125a and second side
edges 125b which are flat and angularly aligned with the first and
second adjacent side edges of the segment, e.g., 48a, 48b,
respectively. The elevation of the fingers 120 may vary. In the
embodiment having a grooved core 12, 14, 16, the elevation of the
fingers 120 may be at least as great as the depth, e.g., 18b of the
groove, e.g., 12, 14, 16, 18, or conversely, less than the depth of
the groove 12, 14, 16. However, the fingers 120 must be of a
narrower width than that of the corresponding groove, so the
fingers 120 can fit into such grooves, e.g., 12, 14, 16. See FIGS.
18, 19. Further, the fingers 120 may be of a uniform or variable
elevation, shape, and width with respect to one another.
[0074] Now referring back to the fingers on the underside of the
segments, in the preferred embodiment, the top and bottom side
surfaces 120f, 120b of the finger 120 has an angle of substantially
90 degrees, relative to the outer surface of the core 11, and has
an inner surface 120d which is substantially parallel to the outer
surface of the core 10. The finger 120 of this design has a square
or rectangular cross-section. See, e.g., FIGS. 5, 18, 20.
[0075] Alternatively, the fingers may be located on the surface of
the core 11, and would be referred to as "bands" (not shown). The
core may have one circumferential band, or a plurality of
circumferential bands. In this case, the bands have corresponding
elements and features equivalent to those found in the fingers. The
bands may be found in an embodiment with or without corresponding
furrows on the underside of the segments (not shown). In this case,
the furrows have corresponding elements and features equivalent to
those found in the grooves of the core. The underside of the
segments may have one furrow, or a plurality of furrows, which
collectively form a circumferential furrow. When there are both
bands and furrows present (not shown), the bands on the surface of
the core 11 (not shown) fit into the corresponding furrows on the
underside of the segments (not shown). The bands may be a variety
of shapes and widths, similar to those described for the fingers.
Preferably, the band has a flat bottom side and a flat top side and
a curved outer surface. The bands may also have a variety of
elevations, and may be at least as great or less than the depth of
the furrow (not shown). Similar to the plurality of fingers and
grooves, a plurality of bands and/or furrows create a tortuous path
of flow for liquids and gases and an increased surface area between
the undersides of the segments and the core which would energize
the segments and push the segments outwardly to cause an outer seal
with the tubulars. Further, a plurality of bands and/or furrows
also provides a tortuous path of flow and effects an inner
turbulent seal and retards the upward flow of liquids and gases and
causing an increase in pressure below the plunger. Similar to the
fingers and grooves, the biasing means may be placed between the
core and the segments. Also similarly, there may be at least one
blind hole in each band that accommodates a biasing means,
discussed below, under each segment. The biasing means may also be
disposed between the band and the furrow (not shown). Further, at
least one furrow in each segment may have a blind hole that
accommodates the biasing means with the biasing means being
disposed between the band and the furrow (not shown).
[0076] The core 10 of the plunger body in FIGS. 16, 17, 18 may also
possess internal sealing means such as one grove or a plurality of
longitudinally spaced circumferential grooves 12, 14, 16, 18 which
are defined by recessed surfaces that are interspersed between the
ungrooved sections of the surface of the core 11. There is also an
inner turbulent sealing effect, FIG. 4, when the embodiment has an
ungrooved core and at least one, or preferably a plurality of
fingers, e.g., 120 that project inwardly toward the core 11. There
is an even more dramatic inner sealing effect where the embodiment
has grooves 12, 14, 16 as well as projections, e.g., 120.
[0077] Each groove, e.g., 12, 14, 16, or 14, 16, 18 is defined by a
recessed surface, e.g., 18b and upper and lower side surfaces,
e.g., 18a and 18c, respectively. In the preferred embodiment, the
lower surface portion 18b has an angle of substantially 180
degrees, relative to the outer surface of the core 11, and have
upper and lower portions 18a, 18c, that have an angle of
substantially 90 degrees, relative to the outer surface of the
ungrooved core 11a. The core of this design has a square or
rectangular cross-section, see, e.g., FIG. 16. The preferred
embodiment of the plunger has a core 10 which includes a plurality,
preferably three, of longitudinally spaced circumferential grooves,
e.g., 12, 14, 16, that divide the peripheral surface of the core 11
into a plurality of outer surface sections, e.g., 11a, 11a. Again,
due to the necessity for clearance between the plunger P and the
tubulars T which allows the plunger to fall or gravitate to the
bottom of the well, a flow passage is formed between the jacket and
the tubulars, and some of the gas below the plunger P will flow up
between the plunger P and the tubulars T, as well as up into the
plunger beneath the jacket assembly and the core. As shown in FIGS.
16, 17, for illustration purposes, the gas also enters into the
flow path 200 between the segment 48 and the core surface 11, 11a,
a first portion F.sub.1 of the gas flows along the surface of the
ungrooved core 11a and the segment underside 63, and a second
portion F.sub.2 flows down into the groove, e.g., 16, 18 and
recessed surface, e.g., 18b. The four right angles at each corner,
13a, 13b, 13c, 13d, and along the recessed surface 18b and the top
18a and bottom sides 18c of the groove 18 cause the first portion
F.sub.1 and second portion F.sub.2 of flowing gas meet at
substantially a right angle at the corner 13a, creating a turbulent
flow region T.sub.1, that inhibits liquid flow downward into the
groove and inhibits gas flow upward out of the groove. The gas
flowing up along the plunger core surface 11, 11a dissipates energy
at each successive groove, e.g., 16, 14, 12. Alternatively, the
grooves may be located in the underside surfaces of the segments,
e.g., 46-49 (not shown). In that situation, the grooves would have
corresponding elements and features equivalent to those found in
the grooves, e.g., 12, 14, 16.
[0078] The groove may also be in the form of a spiral, or
conversely in a variety of geometric shapes, and, for example, may
have a cross-section such as that of a V-shape, or top and bottom
sides that converge or diverge with respect to one another, or a
semicircular cross-section (not shown). Many other variations are
also possible. For example, the depth and/or length of the
recesses, e.g., 18b, may be variable, as well as the length of the
body sections 11a between the recesses. Further, the grooves, e.g.,
12, 14, may be of a uniform or variable depth, shape, and width,
with respect to one another.
[0079] As best seen in FIGS. 16, 18, the preferred embodiment may
also have biasing means, which are typically springs 190, disposed
between the core 10 and the underside or inner surface of the
segment, which biases the segments, e.g., 46, 47, 48, 49, outwardly
from the core 10. The biasing means may take the form of a
helically wound spring 190 or leaf spring or other member which has
the ability to rebound or recoil after being compressed. Further,
the core 10 may possess a blind hole 180, or a blind hole 182 may
be present in the core groove 185, e.g., 12, 14, 16. Preferably
there are two biasing means, e.g., 190 between each segment, e.g.,
46, 47, 48, 49 and the adjacent area of the core 10 or core groove,
e.g., 12, 14, 16. The biasing means 190 are preferably placed about
midway across the width of the segment and at places along the
length of the underside that leave the segment balanced against the
core 10. The blind holes, e.g., 180, 182, accommodate and hold the
biasing means, e.g., 190 in place. The finger of the preferred
embodiment may also have a blind hole 185 that accommodates a
biasing means, e.g., 190. Preferably the embodiment has a blind
hole in both the core 180 or core groove 182 and the underside of
the adjacent segment 185 (not shown) or finger 120. This design
minimizes the risk of loss of the biasing means 190.
[0080] Referring to FIG. 1, the gas below the plunger P must have
sufficient pressure to overcome the weight of the plunger P and a
liquid slug LS on top of the plunger P, and the pay line PL
pressure, in order to move the plunger P up the tubulars T. Due to
the necessity for clearance between the plunger P and the tubulars
T which allows the plunger to fall or gravitate to the bottom of
the well, a flow passage is formed between the jacket 100 and the
tubulars T, and some of the gas below the plunger P will flow up
between the plunger P and the tubulars T, as well as up into the
plunger beneath the jacket assembly 100 and the core 10. As shown
in FIGS. 16, 17 once the gas and/or liquids enter into the flow
path 200 between the segment 48 and the core surface 11, 11a, a
first portion F.sub.1 of the gas flows along the surface of the
core 11 and the segment underside 63, and a second portion F.sub.2
flows down and around the raised finger 120. The four right angles
at each corner of the finger, 120a, 120c, 120e, 120g, and along the
surfaces of the bottom 120b and top sides 120f and inner surface of
the groove 120d, cause the first portion F.sub.1 and second portion
F.sub.2 of flowing gas to meet at substantially a right angle at
the corner 120e, creating a turbulent flow that inhibits liquid
flow downward into the areas of the segment between the fingers
which have lower elevations and inhibits gas flow upward out of the
segment area between the fingers. The gas flowing up along the
plunger core surface 11, 11a dissipates energy at each successive
finger, e.g., 120. There is an even more dramatic inner sealing
effect where the embodiment has some grooves 12, 14, 16 in the core
10, as well as projections, e.g., 120, FIGS. 16, 18.
[0081] The sealing segments 46-49 are mounted around the core 100
of the plunger body and are preferably held in place by a retaining
means such as an upper retaining ring 150 and a lower retaining
ring 160. See FIGS. 2, 4, 18, 19. The retaining rings 150, 160 are
substantially cylindrical and have a hollow inner surface of
slightly larger diameter than the core 10 and a shape that
corresponds to the shape of the core 10. The retaining rings also
have first 151, 161 and second 152, 162 ends, with the first ends
151, 161 having a plurality of lugs positioned next to the
segments, and the seconds ends being positioned on the opposite
side of the segment ends. Preferably the retaining rings 150, 160
have a plurality of lugs, e.g., 163, 164, preferably four, which
are spaced at ninety degree intervals around the retaining rings
150, 160, and which are positioned to protrude inwardly toward the
segments and are oriented to engage the notches 70, 72, 74, 76 at
the upper ends of the segments 46, 47, 48, 49, as in FIGS. 5, 6,
and the lower ends of the segments, e.g., 71, 73. The retaining
rings 150, 160 may also serve to hold the fingers 120 in position
over the grooves, e.g., 12, 14, 16, 18, in the core 10. The upper
retaining ring 150 is slipped over the core 100 of the plunger body
and is positioned adjacent to the segments, 46-49, and may also be
adjacent to the shoulder 410 of the fishing piece 420, which may be
tooled into the top end of the core 10, or removably attached to
the body such as by threading 430. The retaining 150, 160 rings may
be held in place by a set screw 415, which is screwed into a
drilled hole 402 in the core 10. See FIGS. 18, 19. Similarly, the
lower retaining ring 160 is slipped over the core 100 of the
plunger body and is positioned adjacent to the segments, 46-49, and
may also be adjacent to the end cap 220, which may be tooled into
the bottom end of the core 10, or removably attached to the body
such as by threading 225, and may also have corresponding lugs.
Alternatively, the segments, e.g., 21, 23, 48 may have a slotted,
e.g., 21c, 23c or notched top, e.g., 70 and bottom ends, e.g., 71
which slidably fit under the retaining rings, and limit the outward
radial movement of the segments, e.g., 21, 23, 48. See FIGS.
4,8.
[0082] Further, in an embodiment having a grooved core, e.g., 12,
14, 16 and fingers 120, and upper 150 and lower retaining rings
169, the edges of at lease one the groove, typically the uppermost
or lowermost, e.g. 16, of the core 10 is preferably angularly
reduced to allow installation of the segments 46, 47, 48, 49
underneath the upper retaining ring 150. See FIG. 19. Further, the
top or bottom edge 12a of the lowermost or topmost groove, e.g., 12
of the core is angularly reduced 12k to allow installation of the
segments with fingers 120 underneath the lower retaining ring 160.
Of course the fingers 120 of the segments, e.g., 46-49, may also be
present in plungers with grooved cores 12, 14, 16, with fingers
interspersed in the core grooves. In that case, at least one outer
edge of one of the grooves, e.g., 12, or grooves, e.g., 12, 14, 16,
is angularly reduced to allow installation of the segments with
fingers 120 underneath the retaining rings, e.g., 150, 160.
[0083] Referring now to FIGS. 1, 20-25, the operation of an
additional embodiment of a plunger will be explained. FIGS. 20-25,
illustrate an alternate embodiment of the invention that in many
respects is the same as the embodiments of FIGS. 1-19. Similar to
the previous embodiments, the plunger of FIGS. 20, 23, 24, and 25
has a body with a core 10, but also has areas defined as a top end
400, and a bottom end 500. The top end 400 has threading 430 to
which additional parts can be attached. In this embodiment, a
separate piece, such as a fishing part 420 is threadingly connected
to the body at a threaded connection 430. The top end fishing piece
420, like some of the previous embodiments, is provided with a head
area 425 and a reduced neck 424 for engagement by a fishing tool if
required. The bottom end 500 is provided with an external thread
435 to which additional parts can be attached such as a modified
end cap 220 with a corresponding internal thread 221, provides a
threaded connection between the body and the end cap 220. The
modified end cap 220 includes an enlarged chamber portion 510. The
plunger is also provided with an inner passage 460 which may extend
partway through or through the entire body and plunger, a chamber
510, and a closure member 600. The major difference between the
plunger of FIGS. 2 and 18 and the previously described features of
FIGS. 2-19 is the inner passage 460 and the chamber 510 and closure
member 600. Like in the previously described embodiments, the
plungers of FIGS. 20-25 is provided with an outer seal means made
up of a plurality of segments, e.g., 46, 47, 48, 49, or 20-24,
which are substantially similar, if not identical, to the
corresponding elements in the embodiments of FIGS. 2-19. Retaining
rings 150 and 160 hold these segments 46, 47, 48, 49, or 20-24,
collectively the jacket assembly 100 in place but permit yet limit
outward radial movement between an innermost position 290, in which
the exterior cylindrical surfaces thereof lie has a diameter less
than that of any restriction to be encountered in the tubulars T
with which it is to be used, and an outermost position 300 in which
the exterior cylindrical surfaces, e.g., 46, 47, 48, 49 slidingly
and sealingly engage the walls of the tubulars T in which the
plunger P is to be used. Biasing means such as springs 190, bias
these segments toward their outermost position 300. The unique
circumferentially and mutually engageable tabs and slots and the
overlapping opposing tangentially disposed planar surfaces provided
by stepped areas, as in FIGS. 5, 6, 8, 14 thereon allow radial
inward and outward movement while limiting leakage and erosion
caused thereby.
[0084] As in the embodiments shown in FIGS. 2-19, the body of the
plunger also includes an internal sealing means, such as the inner
surfaces of the segments, which may also have rigid fingers 120
projecting inwardly. Or alternatively, the raised surfaces may be
in the form of a rigid band on the surface of the core 11 (not
shown). Preferably, each segment, e.g., 46-49 has three fingers 120
on the underside of each segment, which protrudes radially inward
toward the core 10. The fingers 120 of each segments, e.g., 46-49
are parallel and horizontally aligned with the fingers of the
adjacent segments so the fingers collectively cooperate to encircle
the core 10. As in the previous embodiments, the preferred internal
sealing means also includes a core 10, wherein the surface 11 is
grooved, e.g., 12, 14, 16. Where there are both grooves 12, 14, 16,
in the surface of the core 11 and fingers 120 on the segments 46,
47, 48, 49, the fingers 120 are adjacent to and fit into the
grooves 12, 14, 16, in the core. The fingers 120 are typically
separated from the core 10 unless the fingers are pushed to their
most inward position. Typically during operation, the fingers 120
and core 10 are separated by a space, or flow path 200. This
arrangement of grooves and/or finger projections (or a band located
on the core 10, not shown) creates a tortuous path of flow that
effects an inner turbulent seal.
[0085] The chamber 510 that houses the closure means, such as a
stopper 600, is an enlarged area within the end cap 210, and the
body provides at least one side wall 918, at least partially
surrounding the chamber. As previously mentioned, the end cap 210
is threadingly connected to the lower plunger body portion 500 at
the threaded connection 435. The chamber 510 has a roof 520 at the
upper end which may be inwardly tapered 545 below the roof 520,
with an opening 525 in the roof which communicates with the upper
inner passage 460 and a floor 550 at the lower end with an opening
in the floor into a bore the floor may communicate with a bore
which houses a stem 630 attached to the closure means. Furthermore,
there is an opening 560 at the end of the plunger stem bore passage
560 at the bottom of the end cap 570. When the closure means rests
upon the chamber floor at least part of the time and is in the open
position, which allows fluid and/or gas to enter the inner passage,
the stem protrudes downward 670 from the body of the plunger. In
one embodiment, the roof 520 of the chamber 510 is substantially
horizontal and has edges or walls that correspond with the shape of
the upper side of the closure means. Additionally, the walls 918 of
the chamber may be straight, angled, or curved to correspond with
the shape of the closure means. Further, a stopper 600 with a head
may be used as the closure means. The top end of the head may be
dome shaped, like the roof of FIGS. 20 and 23. In that case, the
floor is nonparallel to the roof. Alternatively, the roof 520 may
be triangular in cross-section and the head of the stopper is
correspondingly cone-shaped or triangular, like that of FIGS.
24-25.
[0086] In an embodiment, the plunger has a chamber that is circular
in cross-section, a floor that is flat, and a flat roof, with the
floor being parallel to the roof. See e.g., FIGS. 37-38. Further,
in an embodiment, the stopper has a triangular top end. See FIGS.
24-25, and FIGS. 26-29, and FIGS. 31, 33, and 34.
[0087] In a further embodiment, the plunger has a chamber with a
floor that is flat, and a dome shaped roof, like that of FIGS. 20
and 23, and a stopper that has a semicircular or dome shaped top
end, like that of FIGS. 20 and 23. There are also other variations
of additional shapes which the chamber roof and chamber floor could
possess, such as a flat roof with straight chamber walls and a
curved or flat floor, and corresponding variations of the shape of
the first end and second end of the stopper, such as a flat top end
and a circular bottom end (see FIG. 23), which could also be
operable.
[0088] The roof 520 of the chamber 510 is further connected to a
downwardly facing and tapered seating surface 530. The area below
the seating surface 530 is also provided with an area partially
defined by a slanted or tapered ramp area 545 below the seating
surface 530. The seating surface 530 of the preferred embodiment is
sized and designed to receive and guide a plunger stopper closure
member 600 albeit rounded, half-sphere, or ball-type, upwardly to
the seating surface 530 in the roof 520. The plunger stopper 600
has a head 615 with a top end 610 and a bottom end 630, wherein the
bottom end of the stopper is substantially curved 635. Conversely,
the bottom end of the stopper may be substantially flat 630. A stem
650 is attached to the bottom end 630 of the head 615.
Alternatively, the top end 610 of the plunger stopper 600 may
further have a stem 670 that is attached to the top end 610 of the
head 615. This stem 670 will be pushed up into the inner passage
460 above the chamber 510, when the bottom end 570 of the plunger
hits the bottom well stop means to further ensure closure of the
opening 525 into the passage 460. (See FIGS. 24, 25). Under certain
conditions, the stopper 600 is moveable between the open position
of FIG. 20, in which fluid and/or gas flow is permitted into the
inlet ports, e.g., 700, 702 in the end cap 220 through the chamber
510 and into the passage of the body 460, through the hole 525 in
the roof 520, and out through the outlet ports, e.g., 715, 716,
717, 718 in the top end. In FIG. 23, the stopper 600 is in a closed
position in which the fluid and/or gas flow through the chamber
opening 545 into the passage 460 of the plunger body is blocked by
the top 610 of the stopper 600. In the open position, the stem 650
extends downwardly through the opening 555 in the hole in the floor
550 of the chamber 510 into the bore 540 in the bottom of the end
cap 560, and protrudes 670 from the lower end of the plunger body
570, when the plunger is descending through the tubulars T, or at
the surface once the motor valve MV has been opened. When the stem
655 and then the bottom end of the plunger reach the bottom of the
well, or some type of bottom well stop or well stop means TS, the
stem 650 and stopper head 615 is forced or pushed upwardly until
the top end of the head 610 is seated against the seating surface
530 of the roof 520 of the chamber 510.
[0089] The fishing part that is attached to the top end also has an
inner passage 460. In one embodiment, the inner passage 460 also
has an opening 720 at the top end of the plunger. As previously
discussed, the fishing part 420 may also have a plurality of outlet
ports 715, 716, 717, 718, or axial inner passages, disposed around
the sides of the collar 410 of the fishing piece 420, in addition
to, or instead of the opening at the top end 720. Preferably, there
are four radial ports, e.g., 715, 716, 717, 718 that are spaced
along the cylindrical axis of the collar at about 45 degrees from
each other.
[0090] Similarly, there are preferably a plurality of radial ports
located along the cylindrical axis of the end cap 220. In an
embodiment, the ports are about 45 degrees from each other 700,
701, 702, and 703. The location of the inlet ports, e.g., 700, 702
in the chamber wall 511 of the end cap 220 are especially
important. The ports 700, 702 are preferably located so that the
inside openings of the ports 710, 712 into the chamber 510 are
located above the top end 610 of the plunger stopper head 615 when
the stopper 600 is in its downward position. Furthermore, these
inlet ports are preferably located so that the inside opening of
the ports 710, 712 will be below the bottom end 630 of the stopper
head 615 when the stopper is in its upward position, closing the
inner passage 460. This placement of the inlet ports assures the
bypassing of liquids through the chamber passage 510 and into inner
passage 460 as the plunger falls in the tubulars T.
[0091] The plungers of the embodiments of FIGS. 20-38 also operate
much as the plunger embodiment of FIGS. 2-5 and 6-19, and may be
described with reference to FIG. 1. Like the plunger P of FIG. 1,
and 2-19, the plunger of FIGS. 20-38 may be placed in the tubing
string T and allowed to fall or gravitate to the bottom of the well
W for producing the subterranean formation F thereof. However, it
will fall more rapidly due to the inner passage 460. When the
bottom end of the plunger 570 reaches the well stop or stop means,
the stem 650 of the closure means such as the stopper 600, and the
head member 615 are pushed upwardly toward the roof and to the
seating surface 530 and the closure means or stopper 600 is seated
against the roof 520. When the plunger P reaches the bumper spring
BS at the bottom of the tubulars, the weight of the plunger pushes
against the well stop TS forcing the stopper stem 650 and head 615
in an upward direction. As soon as the closure member enters or
obstructs the flow path of valve passage, the top end 610 of the
stopper 600 then proceeds past the ramp area 545 and up into the
seating surface 530 in the roof 520. Once the stopper 600 is seated
to assume its closed position seated, the flow of liquids into the
chamber through the inlet ports, e.g., 702, 710 will flow up into
the chamber 510 and against the second end of the plunger head 630
will cause the stopper to assume and maintain its closed position
against the seating surface 530 as illustrated in FIGS. 23, 25. At
this point, the bypassing of fluid through the passage 460 is
blocked and gas pressure is allowed to build up just as with
plunger 1 and 2 of the embodiment illustrated in FIGS. 24 and 5-19.
After a preselected, predetermined period of time, the control
valve MV at the surface is opened by the controller EC and the gas
pressure built up in the well causes the plunger and any well
liquids accumulated in the tubulars T thereabove to be elevated to
the surface and produced through the production or pay line PL.
Once the plunger is detected by sensor S and the control valve V
closed by the controller EC, pressure is equalized in the area of
the lubricating sub E. When that occurs the plunger stopper 600,
due to its own weight, falls back down and reassumes its open
position of FIG. 20-24, and 38. This opens the inner passage 460,
allowing the plunger to descend to the bottom of the well W to
repeat the cycle.
[0092] Of course the concept of the novel bypass and chamber with a
closure member such as a stopper can be utilized in downhole
plungers of any type and design, with or without pads. FIGS. 26-39,
for example, are additional types of plungers in which Applicants'
invention may be incorporated. The plunger of the embodiment of
FIGS. 26-39 operates much as the plunger embodiment in FIGS. 20-25,
as previously described.
[0093] The plungers in FIGS. 26-30 are known as spiral plungers,
FIG. 31 shows a Teflon coated spiral plunger that reduces the
friction between the plunger and well tubulars. FIG. 32 is a
plunger with pads, FIG. 33 is a brush plunger, and FIG. 34 is a
wobble washer plunger where individual washers which move around
the mandrel of the plunger. The plunger of this invention, may also
have at least one external pad disposed about a portion of the
plunger body, with or without a grooved mandrel. See e.g. FIGS.
35-36.
[0094] The spiral plungers of FIGS. 26-32, and the washer plunger
of FIG. 34 also provide a labyrinth type external seal against the
tubulars, and the brush plunger also provides external seal against
the tubulars.
[0095] The plungers of FIGS. 35-36 have pads that provide an
external seal against the tubulars and a flow path between the pads
and the mandrel. The sealing features of the plungers of FIG. 35 is
like that of the plunger and elements of FIGS. 5-18, as previously
described. And, the sealing features of the plunger of FIG. 36 is
like that of the plunger of FIGS. 2-3, as previously described.
[0096] The internal bypass and flow passage of plungers of FIGS.
29-38 function similarly and have common elements. For example, the
plungers of FIGS. 26-34 have a body, and areas defined as a top end
400, and a bottom end 500. They also have an inner passage 460,
chamber 510, and closure means within the chamber, and ports that
open into the chamber. The flow passage in these plunger also has
an opening 720 at the top of the plunger body.
[0097] Spiral plungers, brush plungers, pad plungers, and wobble
washer plungers are well known in the art. These plungers are often
used in well tubulars to clean debris or buildup from the inside or
well tubulars and/or to prevent such build up. Applicants have
improved the operation of such plungers by incorporating an inner
passage, a chamber, and a closure means within the inner chamber of
such plungers. The operation of other plungers can also be improved
by incorporating Applicants' improvements.
[0098] The plunger of the embodiment of FIGS. 26-38 also operates
much as the plunger embodiment of FIGS. 20, and 23-25. Like the
plunger P of FIG. 1, and FIGS. 20-25, the plunger of FIGS. 26-38
may be placed in the tubing string T and allowed to fall or
gravitate to the bottom of the well W for producing the
subterranean formation F thereof. These plungers will fall more
rapidly due to the inner passage 460 than their counterparts that
do not have an inner passage. The inner passage is typically
positioned within the center of the plunger body, and may extend
the entire length of the plunger, or nearly the entire length of
the plunger.
[0099] Similar to the previous embodiments, the plunger of FIGS.
35-38 have a body, and areas defined as a top end 400, and a bottom
end 500. See FIGS. 37-38 The body is typically made of rigid
material, such as any type of metal or metal alloys, rigid plastics
and polymers, ceramics, and the like, or other materials used or
known by one skilled in the art, with the preferred embodiment
being made of stainless steel to resist corrosion.
[0100] The wall thickness 900 of the plunger body varies upon the
material used. It is also important to note that in plungers that
do not have a grooved mandrel or a body with external spirals 902,
the bore area that houses the inner passage 460 can be enlarged
since the mandrel or body is not being decreased in thickness to
make grooves.
[0101] In an embodiment, a fishing part can be included, but is not
required. The fishing part can be internal or external. The fishing
part may be a separate piece 420 connected to the body, or may be a
part of the body. The top end fishing piece 420, like some of the
previous embodiments, is provided with a head area 425 and a
reduced neck 424 for engagement by a fishing tool if required. See
FIGS. 35-36. Alternatively, the plunger may have an internal
modification 420a to facilitate fishing of the plunger from the
tubulars. See FIGS. 37-38.
[0102] The plunger is also provided with an inner passage 460 which
may extend partway through or through the entire body. In an
embodiment, part of the inner passage is also enlarged and forms a
chamber 510. In an embodiment, the inner passage 460 extends to the
top end of the plunger, and communicates with an opening in the top
720 of the plunger. The chamber 510 may house a closure member,
such as a stopper 600, is an enlarged area within the bottom end of
the plunger 210. The chamber bottom can be screwed to the body of
the plunger through as for example by threads, or can be threaded
on and/or welded and/or pinned 904 on, or secured with screws and
welded, or simply connected by welding 850. As previously
mentioned, the chamber may be incorporated through an end cap 210
that is removably or permanently connected to the lower plunger
body portion 500, e.g., such as threaded connection 435. See FIGS.
35-36. In any case, at least a portion of the bottom end of the
plunger is preferably removable so that a closure member can be
placed within the chamber. The bottom end may be attached to the
body of the plunger in various ways known to one skilled in the
art, including but not limited to by welding, pins, screws and the
like. The bottom end 500 may have threads 435 to which parts can be
attached such as a modified end cap 220.
[0103] The chamber 510 has a roof 520 at the upper end with an
opening 525 in the roof, which communicates with the inner passage
460 and a floor 550 at the lower end with an opening 555. In an
embodiment, there is a bore 540 that extends from the floor to the
bottom of the plunger. In an embodiment, the bore 540 houses a stem
630 that is attached to the closure member. In one embodiment, the
roof 520 of the chamber 510 is substantially curved and has a
stopper 600 with a head 615 whose top end 610 is correspondingly
curved 605, like the roof 520 of FIGS. 20 and 23. Alternatively,
the roof 520 may be triangular in cross-section and the head of the
stopper is correspondingly cone-shaped, like that shown in FIGS.
24-25. There are also other variations of additional shapes which
the chamber roof and chamber floor could possess, such as a flat
roof with straight chamber sides and a flat or curved floor, and
corresponding variations of the shape of the top end and bottom end
of the stopper, such as a flat top end and a circular bottom end,
which could also be operable. However, for ease of manufacture, the
chamber has sides 908 that are straight or substantially straight,
and has a flat bottom floor 550. See FIGS. 37-38. Further, the roof
is flat and has an opening 525 in it in which a portion of the
stopper becomes seated. See FIGS. 37-38.
[0104] The roof 520 of the chamber 510 may also have a seating
surface 530. The seating surface 530 may be or may have an area
partially defined by a slanted or tapered ramp area 545 as in FIGS.
20 and 24. The seating surface 530 of the preferred embodiment is
sized and designed to receive and guide a plunger stopper closure
member 600 albeit rounded, half-sphere, or ball-type, upwardly to
the seating surface 530 in the roof 520. The closure member may
take various forms and shapes such as that shown in FIGS. 20,
23-29, 31, 33-34, 35-38, or may be in the form of a check type
valve or any other type of closure member known or used by one
skilled in the art. In an embodiment, the closure member is a
plunger stopper 600 has a head 615 with a top end 610 and a bottom
end 630. See FIGS. 37-38. A stem 650 is attached to the bottom end
630 of the head 615 of the stopper or the lower end of the closure
member. The stem protrudes downward from the body of the plunger
when the closure member is in the open position. See FIGS. 38. Of
course the chamber could be located above the bottom end of the
plunger, with a longer stem attached to the closure means.
[0105] In a further embodiment, the top end 610 of the plunger
stopper 600 may also have a stem 670 that is attached thereto. This
stem will be pushed up into the inner passage 460 above the chamber
510, when the bottom end 570 of the plunger hits the bottom well
stop means to further ensure closure of the opening 525 into the
inner passage 460. See FIGS. 24-25.
[0106] The plunger is placed within the tubulars with the closure
means in the open position. Under certain conditions, the closure
means such as a stopper 600 is moveable between the open position
of FIG. 38, in which fluid and/or gas flow is permitted into the
inlet ports, e.g., 700, 702 in the end cap 220 through the chamber
510 and into the inner passage of the body 460, through the hole
525 in the roof 520, and out through the outlet port, e.g., 710 in
the top end, and the closed position of e.g., FIG. 37. The plunger
body in the area near the ports must have a reduced diameter so
that fluids 912 below and beside the plunger may enter the ports.
See FIG. 38. FIG. 1A also shows fluids entering the chamber at the
area between the plunger body and the tubulars. In FIGS. 26-29, 31,
33-37, the stopper 600 is in a closed position in which the fluid
and/or gas flow through the chamber opening 545 into the passage
460 of the plunger body is blocked by the top 610 of the stopper
600.
[0107] During the decent of the plunger within the tubulars, the
closure means is held in the open position by the mere weight of
the closure means due to gravity, and the flow of the gas and/or
fluid above the closure means through the ports that open into the
chamber. The bottom of the stem must still touch the well stop to
become pushed into the closed position. In the open position, a
stem 650 that is attached to the bottom end of the closure means
extends downwardly through the opening 555 in the hole in the floor
550 of the chamber 510 into the bore 540 in the bottom of the end
cap 560, and protrudes 670 from the lower end of the plunger body
570, when the plunger is descending through the tubulars T, or at
the surface once the motor valve MV has been opened such as in FIG.
1. When the stem 655 and then the bottom end of the plunger reach
the bottom of the well, or some type of bottom well stop or well
stop means TS, the stem 650 and the closure means is forced or
pushed upwardly until the top end of the closure means is seated
against the roof 520 of the chamber 510.
[0108] There may be additional outlet ports in the plunger body
near the top end to increase flow. For example, the fishing part
420 may also have a plurality of outlet ports disposed around the
sides of the collar 410 of the plunger body that has a reduced
diameter, in addition to, or instead of the opening at the top end
720. Preferably, there is a plurality of ports, e.g., 715, 716. In
an embodiment, the ports are located along the cylindrical axis of
the collar. Further, in an embodiment, the ports are evenly spaced
with respect to one another.
[0109] Again, there are preferably a plurality of ports that are
spaced along the cylindrical axis of the end cap 220. In an
embodiment, are spaced around the cap at equal distances at about
45 degrees from each other 700, 701, 702, and 703. The location of
the inlet ports, e.g., 700, 702 in the chamber wall 511 of the end
cap 220 are especially important. The ports 700, 702 are preferably
located so that the inside openings of the ports 710, 712 into the
chamber 510 are located above the top end 610 of the plunger
stopper head 615 when the stopper 600 is in its downward position.
FIG. 39 shows a chamber with a plurality of ports 700, 701 and 702.
Furthermore, these ports are preferably located so that the inside
opening of the ports 710, 712 in the chamber will be below the
bottom end 630 of the stopper head 615 when the stopper is in its
upward position, closing the inner passage 460. This placement of
the inlet ports assures the bypassing of gases and/or liquids
through the chamber passage 510 and into inner passage 460 as the
plunger falls in the tubulars T.
[0110] Also in an embodiment the ports in the chamber have an
oblong shape 910, such as an oval or rectangle so as to minimize
the amount of surface area that would be taken out by for example,
a port that is circular, that could weaken the body structure. See
FIGS. 37-38.
[0111] In an embodiment the flow area through the ports in the
chamber is greater than the flow through the inner passage of the
plunger to create a back pressure and choking effect. This choking
effect assists in keeping the stopper in the open position during
the descent of the plunger.
[0112] In tests conducted in a 10,000 foot low pressure gas well, a
normal pad plunger without the bypass and inner passage took about
one hour to descend to the well bottom. In contrast a two-inch
diameter plunger with the novel bypass with an inner passage of
about one inch in diameter took only about ten to fifteen minutes
to descend to the well bottom. This decreased cycle time increased
the gas output of the well from about 180 mcfd (180,000 cubic
feet/day) to about 330 mcfd. (330,000 cubic feet/day).
[0113] The plunger of the present invention has a number of unique
elements. However, many variations of the invention can be made by
those skilled in the art without departing from the spirit of the
invention. Accordingly, it is intended that the scope of the
invention be limited only by the claims that follow. Of course, the
present invention is not intended to be restricted to any
particular form or arrangement, or any specific embodiment
disclosed herein, or any specific use, since the present invention
may be modified in various ways without departing from the spirit
or scope of the claimed invention herein. Furthermore, the figures
of the various embodiments is intended only for illustration and
for disclosure of operative embodiments and not to show all of the
various forms or modifications in which the present invention might
be embodied or operated. The present invention has also been
described in considerable detail in order to comply with the patent
laws by providing full public disclosure of at least one of its
forms. However, this detailed description is not intended to limit
the broad features or principles of the present invention in any
way, or to limit the scope of the patent monopoly to be
granted.
* * * * *