U.S. patent application number 11/270672 was filed with the patent office on 2007-05-10 for helical rod guide and method.
Invention is credited to Gary E. Abdo.
Application Number | 20070102151 11/270672 |
Document ID | / |
Family ID | 38002574 |
Filed Date | 2007-05-10 |
United States Patent
Application |
20070102151 |
Kind Code |
A1 |
Abdo; Gary E. |
May 10, 2007 |
Helical rod guide and method
Abstract
A rod guide 10 for positioning on a sucker rod includes a
sleeve-shaped guide body 12 and two or more spiraling vanes 14, 16
each extending radially outward from the sleeve-shaped body, with
each vane spiraling about the body and defining a flow path between
circumferentially spaced vanes. Each vane has a forward portion 24
spiraling in a forward direction, and a backward portion 26
spiraling in a backward direction rotatably opposite the forward
direction. The rod guide may be used for either reciprocating rod
or rotating rod applications.
Inventors: |
Abdo; Gary E.; (Edmond,
OK) |
Correspondence
Address: |
Browning Bushman P.C.
Suite 1800
5718 Westheimer
Houston
TX
77057-5771
US
|
Family ID: |
38002574 |
Appl. No.: |
11/270672 |
Filed: |
November 9, 2005 |
Current U.S.
Class: |
166/241.4 |
Current CPC
Class: |
E21B 17/1071 20130101;
E21B 17/22 20130101 |
Class at
Publication: |
166/241.4 |
International
Class: |
E21B 17/10 20060101
E21B017/10 |
Claims
1. A rod guide for positioning on a sucker rod, comprising: a
sleeve-shaped guide body for positioning about the sucker rod; two
or more vanes each extending radially outward from the
sleeve-shaped guide body, each vane spiraling about the guide body
and defining a flow path between circumferentially spaced vanes;
and each vane having a forward portion spiraling in a forward
direction, and a backward portion spiraling in a backward direction
rotatably opposite the forward direction.
2. A rod guide as defined in claim 1, wherein the forward -and
backward portions of each vane meet to form an axially elongate and
continuous vane.
3. A rod guide as defined in claim 1, wherein the forward and
backward portions of each vane meet adjacent a middle region of the
guide body.
4. A rod guide as defined in claim 3, wherein the forward and
backward portions of each vane meet at substantially an axial
center of the sleeve-shaped guide body.
5. A rod guide as defined in claim 1, wherein an end of each vane
is tapered radially inward toward the sleeve-shaped guide body.
6. A rod guide as defined in claim 1, wherein each vane extends
circumferentially about the guide body from 130.degree. to
220.degree..
7. A rod guide as defined in claim 1, further comprising: a rounded
transition region between the forward directed portion and the
backward directed portion of each vane.
8. A rod guide as defined in claim 1, wherein the rod guide is
fabricated from plastic.
9. A rod guide as defined in claim 1, wherein the rod guide is
molded onto the sucker rod.
10. A rod guide as defined in claim 1, wherein each vane has a
circumferential width of from 30 to 60.degree..
11. A rod guide as defined in claim 1, wherein each of a left side,
a right side, and a radially exterior surfaces of each vane form a
substantially curved planar surface.
12. A rod guide for positioning on a sucker rod, comprising: a
plastic material sleeve-shaped guide body for positioning about the
sucker rod; one or more plastic material vanes extending radially
outward from the sleeve-shaped guide body, each vane spiraling
about the body and defining a flow path between circumferentially
spaced from the one or more vanes; and each vane having a forward
portion spiraling in a forward direction, and a backward portion
spiraling in a backward direction rotatably opposite the forward
direction, the forward and backward portions meeting to form an
axially elongate and continuous vane.
13. A rod guide as defined in claim 12, wherein the forward and
backward portions of each vane meet adjacent a middle region of the
guide body.
14. A rod guide as defined in claim 12, wherein an end of each vane
is tapered radially inward toward the guide body.
15. A rod guide as defined in claim 12, wherein the rod guide is
molded onto the sucker rod.
16. A rod guide as defined in claim 12, wherein the sucker rod is
reciprocated within a tubing string, such that a radially exterior
surface of each vane slides along an interior surface of the tubing
string.
17. A rod guide as defined in claim 12, wherein the sucker rod is
rotated within a tubing string, such that a radial external surface
of each vane rotatably engages an interior surface of the tubing
string.
18. A rod guide for positioning on a sucker rod, comprising: a
sleeve-shaped guide body for positioning about the sucker rod; two
or more plastic material vanes each extending radially outward from
the sleeve-shaped guide body, each vane spiraling about the guide
body and defining a flow path between circumferentially spaced
vanes; each vane having a forward portion spiraling in a forward
direction, and a backward portion spiraling in a backward direction
rotatably opposite the forward direction; and wherein each vane
extends circumferentially about the guide body from 130.degree. to
220.degree..
19. A rod guide as defined in claim 18, wherein each vane has a
circumferential width of from 30 to 60.degree..
20. A rod guide as defined in claim 18, further comprising: a
rounded transition region between the forward directed portion and
the backward directed portion of each vane.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to rod guides and scrapers
supported on a sucker rod for removing debris 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 rod guide or scraper with vanes spiraling
along the length of the guide and fluid flow channels between the
one or more vanes, and to a method of molding such a rod guide.
BACKGROUND OF THE INVENTION
[0002] Various types of rod guides and scrapers have been devised
to remove wax, paraffin, and other debris from the interior wall of
production tubing. Most rod guides include a sleeve-shaped body for
positioning over the sucker rod and one or more vanes projecting
radially from the body, with one or more vanes being relatively
straight (parallel to the axis of the rod), slanted (inclined at an
angle relative to the axis of the rod), or helical (spiraling
relative to the axis of the rod). The spacing between the vanes, or
between a slanted or spiraling single vane, serves as a flow path
for passing production fluid past the rod guide.
[0003] Most rod guides today are manufactured from a plastic
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 rigid with the sucker rod due to the molding
process.
[0004] 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 guides do, however,
cause high fluid drag forces to fluid passing by the rod guide and
to the surface.
[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] In one embodiment, the rod guide for positioning on a sucker
rod includes a sleeve-shaped guide body and two or more vanes each
extending radially outward from the sleeve-shaped body. Each vane
spirals about the body and defines a flow path between
circumferentially spaced vanes. Each vane has a forward portion
spiraling in a forward direction, and a backward portion spiraling
in a backward direction rotatably opposite the forward
direction.
[0008] In one embodiment, the rod guide includes a plastic material
sleeve-shaped guide body, and the forward and backward portions
meet adjacent a middle region of the guide body to form an axially
elongate and continuous vane. The rod guide may be molded by
engaging first and second molds to form a radially inner chamber
within the engaged molds to define a sleeve-shaped guide body, with
the first and second molds forming a radially outer chamber
extending radially outward from and in communication with the inner
chamber and defining one or more spiral vanes. Each vane has a
forward portion spiraling in a forward direction and a backward
portion spiraling in a backward direction rotatably opposite the
forward direction.
[0009] These and further features and advantages of the present
invention will become apparent from the following detailed
description, wherein reference is made to the figures in the
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a pictorial view of a suitable rod guide molded on
a sucker rod.
[0011] FIG. 2 is another view of the rod guide shown in FIG. 1.
[0012] FIG. 3 is a canted top view of the rod guide shown in FIGS.
1 and 2.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0013] FIG. 1 depicts a plastic material rod guide 10 according to
this invention. Referring briefly to FIG. 3, the rod guide 10
includes a generally sleeve-shaped guide body 12 for positioning on
a sucker rod, and two or more vanes 14, 16 each extending radially
outward from the sleeve-shaped body 12, with each vane spiraling
about the guide body and defining a fluid flow path 18, 20 between
circumferentially spaced vanes. As shown in FIG. 1, the rod guide
may be of a molded one-piece construction fixed to a rod 22 during
the molding process, in which case the rod guide is well suited for
use with a reciprocating rod to clean the interior of production
tubing. If desired, a sucker rod rotator may be used to slowly
rotate the sucker rod and thus the guide 10 with respect to the
tubing string during use. In another embodiment, the rod guide 10
may be mounted on the sucker rod 10, which rotates to drive a
progressive cavity pump, with the rotating rod guide engaging the
interior of the tubing string.
[0014] As shown in FIG. 1, each vane has a forward portion 24
spiraling in a forward direction, and a backward portion 26
spiraling in a backward direction rotatably opposite the forward
direction. The terms "forward" and "backward" are not intended to
be indicative of direction, and only indicate that one portion of
the vane spirals in a rotatably opposite direction from the other
portion. Looking at the rod guide shown in FIGS. 1 and moving
downward along the guide, the forward portion may be the clockwise
direction and the backward portion the counterclockwise direction,
but the forward portion could alternatively be the counterclockwise
direction and the backward portion the clockwise direction.
[0015] Referring still to FIG. 1, the forward and backward portions
24, 26 each meet adjacent a middle region of the guide body to form
an axially elongate and continuous vane, and in the disclosed
embodiment these portions meet at substantially an axial center of
the sleeve-shaped body. In order to minimize the flow losses of
fluid passing by the rod guide and between the vanes, the forward
and backward portions are substantially mirror images of one
another and have substantially the same spiral taper and
substantially the same axial length. Each end 28, 30 of each vane
is tapered radially inward toward the sleeve-shaped guide body, as
shown. The end, 28, 30 may define side surfaces extending radially
inward toward the center of the guide in a direction moving axially
toward the extreme end of the guide, thereby facilitating molding
of the guide.
[0016] In a preferred embodiment, each vane 14, 16 has a left-side
surface 32 as shown in FIG. 2, a right-side surface 34 which is
substantially parallel to the left-side surface of a respective
vane, and the radially exterior surface 36 which extends between
the left-side and the right-side surfaces. Each of these surfaces
is a substantially curved planar surface, and each vane has a
circumferential width of from 30.degree. to 60.degree.. Each vane
also extends circumferentially about the guide body from
130.degree. to 220.degree. to provide a substantial circumferential
area for cleaning the production tubing string while retaining a
relatively large flow area for fluid passage by the rod guide.
[0017] By providing the rod guide with both a forward spiraling
portion and a backward spiraling portion, fluid drag through the
rod guide is minimized compared to an embodiment which continued to
spiral the vanes along the length of the guide in a single
direction. Also, a rounded transition region 38 is provided between
the forward directed portion and the backward directed portion of
each vane and further reduces fluid drag. A circumferential width
of each flow passage is from about 120.degree. to about
150.degree..
[0018] Although the rod guide as disclosed herein is well suited
for use on a reciprocating rod string, the rod guide may also be
used on a rotating rod string for driving a PC pump. For this
latter application, the guide may be fixedly molded to the rod
string as for the reciprocating rod application. The guide provides
a large bearing area, which is the exterior surface of the vanes,
for engaging the interior of the tubing string to provide for long
life. Although the guide as disclosed herein for preferred
applications may have two generally radially opposing vanes, the
guide may be provided with one or more vanes, with each vane having
a forward portion spiraling in a forward direction and a backward
portion spiraling in a backward direction rotatably opposite the
forward direction. If three or more vanes are provided, each of the
vanes would generally be positioned at consistent intervals about
the circumference of the sleeve-shaped guide body, so that three
vanes would be spaced at substantially 120.degree. intervals.
[0019] The rod guide may be molded for fixing on a sucker rod
utilizing first and second molds which engage to form a radially
inner chamber in the engaged molds defining the sleeve-shaped guide
body. The first and second molds may also form a radially outer
chamber extending radially outward from and in communication with
the inner chamber, and define the one or more spiraling vanes each
having a forward portion spiraling in a forward direction and a
backward portion spiraling in a backward direction rotatably
opposite the forward direction.
[0020] Although specific embodiments of the invention have been
described herein in some detail, this has been done solely for the
purposes of explaining the various aspects of the invention, and is
not intended to limit the scope of the invention as defined in the
claims which follow. Those skilled in the art will understand that
the embodiment shown and described is exemplary, and various other
substitutions, alterations and modifications, including but not
limited to those design alternatives specifically discussed herein,
may be made in the practice of the invention without departing from
its scope.
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