U.S. patent application number 13/111361 was filed with the patent office on 2012-11-22 for rod guide with wrapping vanes.
Invention is credited to Daryl Kaltwasser.
Application Number | 20120292021 13/111361 |
Document ID | / |
Family ID | 47174072 |
Filed Date | 2012-11-22 |
United States Patent
Application |
20120292021 |
Kind Code |
A1 |
Kaltwasser; Daryl |
November 22, 2012 |
Rod Guide With Wrapping Vanes
Abstract
A sucker rod guide includes a pair of vanes, offset from one
another by 180.degree., with each vane wrapping approximately
180.degree. around the rod guide. The vanes wrap around the body of
the guide, and are neither spiral nor helical because the surfaces
of the vanes extending radially outwardly from the body of the rod
guide define two dimensional planar surfaces, i.e. flat planes. The
vane thickness varies from a maximum at each end of the vane to a
minimum at a midway point along the vane. This shape assists in
moving fluid up the production tubing when the guide is applied to
a rotary system, such as a progressive cavity pump. This shape also
enhances the erodable volume of the vanes at the extremities, while
providing a less inhibiting path for the flow of fluid in
reciprocating applications.
Inventors: |
Kaltwasser; Daryl; (Katy,
TX) |
Family ID: |
47174072 |
Appl. No.: |
13/111361 |
Filed: |
May 19, 2011 |
Current U.S.
Class: |
166/241.4 |
Current CPC
Class: |
E21B 17/22 20130101;
E21B 17/1071 20130101 |
Class at
Publication: |
166/241.4 |
International
Class: |
E21B 17/10 20060101
E21B017/10 |
Claims
1. A rod guide comprising: an elongate cylindrical body; a first
vane extending radially outwardly from the body, the first vane
defining opposing, parallel, flat, two-dimensional first and second
side walls, the first vane wrapping substantially half-way around
the body; and a second vane extending radially outwardly from the
body, the second vane defining opposing, parallel, flat,
two-dimensional third and fourth side walls, the first vane
wrapping substantially half-way around the body.
2. The rod guide of claim 1, wherein the first and second vanes are
offset from one another by substantially 180.degree..
3. The rod guide of claim 1, wherein the body defines a first end
and a second end, and further comprising: a first conical end cap
extending from the first end of the body; and a second conical end
cap extending from the second end of the body.
4. The rod guide of claim 1, wherein the first vane defines a first
end, a second end, and a middle, and wherein the first vane defines
a maximum width and the first end and the second end and a minimum
width at the middle.
5. The rod guide of claim 4, further comprising: a first conical
end cap extending from the first end of the body; a second conical
end cap extending from the second end of the body; a first angled
edge between the first end of the first vane and the first conical
end cap; and a second angled edge between the second end of the
first vane and the second conical end cap.
6. The rod guide of claim 5, wherein the first angled edge defines
a first straight, non-wrapping vane segment and further wherein the
second angled edge defines a second straight, non-wrapping vane
segment.
Description
FIELD OF THE INVENTION
[0001] The present invention relates generally to the field of
sucker rod guides and scrapers for removing paraffin and other
extraneous materials from the interior wall of production tubing
and protecting the tubing and sucker rod couplings from excessive
wear. More particularly, the present invention relates to a sucker
rod guide with a pair of helical vanes along a portion of the
length of the guide and fluid flow channels between the vanes.
BACKGROUND OF THE INVENTION
[0002] Various types of rod guides and scrapers have been devised
to remove paraffin and other material from the interior wall of
production tubing. Many rod guides include a cylindrical body
molded onto a sucker rod and one or more vanes projecting radially
from the body. In some cases, one or more vanes are substantially
straight (i.e. parallel to the axis of the rod), and in other cases
the vanes are slanted (i.e. inclined at an angle relative to the
axis of the rod). In still other cases, the vanes may be helical
(i.e. spiraling relative to the axis of the rod). The space between
the vanes, or between a slanted vane, defines a flow path for
production fluid past the rod guide.
[0003] Most rod guides today are manufactured from a polymeric
material. Rod guides may be secured in various ways to the sucker
rod. In one application, the rod guide is molded onto the sucker
rod and is thus immobile relative to the sucker rod. In other
applications, the sucker rod includes an open seam which is opened
in order to affix the rod guide to the sucker rod.
[0004] As described in U.S. Pat. No. 7,731,885 to Abdo, for many
applications, a rod guide provided with spiraling vanes is
preferred over a straight or slanted vane guide, since more of the
circumference of the tubing may be cleaned by a single spiraling
guide compared to a single straight-vane guide in a reciprocating
rod application. Spiraling rod guide vanes shown and described by
Abdo included a forward portion spiraling in a forward direction
and a backward portion spiraling in a backward direction rotatably
opposite the forward direction. This arrangement creates a tortuous
path, however, and causes high fluid drag forces to fluid passing
between the rod guide and the interior surface of the production
tubing.
[0005] U.S. Pat. No. 5,277,254 discloses a helical rod guide for
use with a progressing cavity pump rod. The helical guide may
employ either one or two lead vanes. U.S. Pat. No. 6,182,754
discloses a helical scraper for a reciprocating sucker rod. Each of
two vanes extends 180.degree. about the body, with the ends of a
flow channel between the vanes being parallel to the body of the
sucker rod. U.S. Pat. No. 6,439,311 discloses a method of retarding
sand buildup by employing helical vanes which are affixed to
connective rods by shrink couplings. Other patents of interest
include U.S. Pat. Nos. 5,660,534, 5,941,312, 6,065,537, 6,290,475,
and 6,484,882, and Canadian Patents 2,260,710 and 2,291,394.
[0006] The disadvantages of the prior art are overcome by the
present invention, and an improved rod guide and method of molding
a rod guide are hereinafter disclosed.
SUMMARY OF THE INVENTION
[0007] The present invention addresses these and other shortcomings
in the art by providing a pair of vanes, offset from one another by
180.degree., and each vane wrapping approximately 180.degree.
around the rod guide. Vanes in the art that are shown and described
in the references above have been variously described as "spiral"
or "helical". The vanes in the present invention are neither spiral
nor helical because the surfaces of the vanes extending radially
outwardly from the body of the rod guide define two dimensional
planar surfaces, i.e. flat planes, while the corresponding surfaces
of the vanes shown and described in the art define curvilinear
planes.
[0008] Thus, the vane thickness in the present invention varies
from a maximum at each end of the vane to a minimum at a midway
point along the vane. This shape assists in moving fluid up the
production tubing when the guide is applied to a rotary system,
such as a progressive cavity pump. This shape also enhances the
erodable volume of the vanes at the extremities, while providing a
less inhibited path for the flow of fluid in reciprocating
applications.
[0009] These and other features and advantages of this invention
will be readily apparent to those skilled in the art.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] So that the manner in which the above recited features,
advantages and objects of the present invention are attained and
can be understood in detail, more particular description of the
invention, briefly summarized above, may be had by reference to
embodiments thereof which are illustrated in the appended
drawings.
[0011] FIG. 1 is a front perspective view of a sucker rod with a
rod guide of the present invention molded thereon a coupled to a
down-hole pump.
[0012] FIG. 2 is section view of the rod guide molded to a sucker
rod.
[0013] FIG. 3 is a front perspective view of the rod guide.
[0014] FIG. 4 is a side perspective view of the rod guide of FIG. 3
rotated by 90.degree..
[0015] FIG. 5 is an end view of the sucker rod and rod guide of
FIG. 3.
[0016] FIG. 6 is a section view of the rod guide taken along
section lines 6-6 of FIG. 4.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT
[0017] FIG. 1 depicts a presently preferred embodiment of a rod
guide 10 with wrapping vanes 11, in accordance with the teachings
of the present invention. While only one rod guide is depicted, it
is understood that many such rod guides, spaced apart, will be used
in operation. The rod guide 10 is preferably molded onto a sucker
rod 12, although the rod guide may be firmly affixed to the sucker
rod in any manner now known or later developed. A pump 14 is
coupled to the bottom end of the sucker rod 12 in a manner well
known in the art. The pump 14 is positioned within a casing 16 is
pump fluids from the region surrounding the pump 14, up the casing,
around the various rod guides 10, to the surface (not shown).
[0018] The plurality of rod guides are specifically adapted to
operate within one of a number of standard casing diameters. Thus,
there is a design clearance between the vanes 11 and an interior
surface 18 of the casing. This keeps the sucker rod centralized
within the casing and prevents the sucker rod from rubbing against
the interior surface of the casing. The sucker rod, the rod guides,
and the pump are coaxially aligned along an axis 20.
[0019] FIG. 2 illustrates a cross section of a rod guide 10. The
rod guide 10 defines two wrapping vanes 11, as previously
described. Each vane 11 an upper angled edge 22 and a lower angled
edge 24. The angled edges 22 and 24 reduce hydrodynamic resistance
to fluid flow by the rod guide. A conical end cap 26 tapers from
the upper angled edge 22 down to the sucker rod. Similarly, a
conical end cap 28 tapers from the lower angled edge 24. Note that
the angled edge 22 provides a straight, non-wrapping vane segment
between the end of the wrapping vane 11 and the conical end cap 26,
and the angled edge 24 provides a straight, non-wrapping vane
segment between the end of the wrapping vane 11 and the conical end
cap 28.
[0020] FIGS. 3 through 6 provide details of the structure of the
rod guide with wrapping vanes of this invention. FIG. 3 illustrates
a front view of the rod guide, while FIG. 4 shows the rod guide
rotated by 90.degree.. FIG. 3 most clearly shows a feature of this
invention, i.e. a flat, two-dimensional surface 30 on one side of a
vane 11' and a flat, two-dimensional surface 32 on the opposite
side of the vane 11'. This flat surface feature reduces fluid drag
and simplifies the manufacturing process because the mold is easier
to open with the flat surfaces.
[0021] As shown in FIG. 4, the vane 11' and a vane 11'' overlap
along a centerline 34 by roughly the width of a vane. Thus, each
vane subtends roughly 180.degree. around the rod guide. The vane
11'' also includes a flat, two-dimensional surface 36 extending
radially outwardly from an elongate, cylindrical body 38. The vane
11'' includes a flat, two-dimensional surface 40 on the opposite
side of the vane 11'' (see FIG. 6). With this orientation, each
vane defines a minimum thickness at a mid-point along the vane and
maximum thickness at each end of the vane.
[0022] The principles, preferred embodiment, and mode of operation
of the present invention have been described in the foregoing
specification. This invention is not to be construed as limited to
the particular forms disclosed, since these are regarded as
illustrative rather than restrictive. Moreover, variations and
changes may be made by those skilled in the art without departing
from the spirit of the invention.
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