Device for Slip Engagement of Large Tolerance Pipe and Method of Use

Abstract

A coupling for a pipe comprises a housing adapted to accept a pipe within an interior portion of the housing and a cone disposed within the housing where, in embodiments, the cone is further adapted to accept the pipe and be allowed to yield rather than the pipe.

Description

PRIORITY INFORMATION

This application claims the benefit of U.S. Provisional Application No. 60/809,003, filed on May 26, 2006.

FIELD OF THE INVENTION

The invention relates to devices used for engaging pipes. In embodiments, the invention more specifically relates to a device for use with slip engagement of pipes such as large tolerance pipes.

BACKGROUND OF THE INVENTION

Current mechanically set Smart Flange Plus® connectors work on pipes with a diameter tolerance of +1/−0%. However, the American Petroleum Institute (API) pipe tolerance is as great as +/−1%. Providing a full range of API tolerances on Smart Flange Plus® connectors may lead to buckling the pipe that is made to the high side tolerance (1%).

Further, the pipe load in the Smart Flange Plus® connector is statically balanced by the cone.

Additionally, cone material strength may be manipulated so that its yield point and strain characteristics closely balance to that of the pipe. Thus, when a connector, e.g. a Smart Flange Plus® connector, is made up and the pipe begins to yield prior to buckling, the cone itself also reaches yield. Further makeup yields the cone, not the pipe.

BRIEF DESCRIPTION OF THE DRAWINGS

The features, aspects, and advantages of the present invention will become more fully apparent from the following description, appended claims, and accompanying drawings in which:

FIGS. 1-2 are views of embodiments, either in partial perspective or in partial perspective cutaway, of embodiments of the invention.

FIG. 3 is a graph of loads on a pipe inserted into a coupling.

FIGS. 4 and 5 are flowcharts of embodiments of the disclosed methods.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

In general, pipe is typically loaded in compression, but compression is unstable and the pipe has limited contraction before buckling. The cone is loaded in hoop, i.e. circumferential, tension which is stable. Typically, the cone can take high dialation strain.

Materials such as soft steels (e.g. A36, A105, C1020) have real strain elongations on the order of 30%. Austenitic stainless materials, e.g. 3xx series, have strain elongations on the order of 40%.

Certain slips, as that term is understood by those of ordinary skill in the pipe setting arts, comprise angled slip teeth where the slip teeth angles are in the neighborhood of the friction angle, as that term is understood by those of ordinary skill in these arts. This keeps axial loads from the pipe during service from exerting radial loads on the cone.

Referring to FIG. 1, as the context requires herein, flange 10 generally comprises flange 10a and flange assembly 10b. In a preferred embodiment, flange 10a is a Smart Flange Plus® flange. Flange assembly 10b is as basically described herein. When the joint is made, flange 10a is made against flange assembly 10b. As studs 17 tighten, a piston (generally shown at 18) pushes slips 300 into cone 200.

Flange 10 for pipe 12 in an embodiment is a coupling comprising housing 100 adapted to accept pipe 12 within interior portion 111 of housing 100 and cone 200 disposed within housing 100.

In certain currently contemplated embodiments, housing 100 may be made of A105, A694, A350, 4130, and/or 4140 steel or the like.

Housing 100 may further comprise seal 120 disposed about interior surface 112 of housing 100 where seal 120 is adapted to conform to outer surface 13 of pipe 12 when pipe 12 is inserted at least partially into housing 110. Seal 120 is made of a suitable material and may comprise nitrile (NBR), fluoroelastomer (FKM), or polyurethane (PUR), or the like, or combinations thereof.

In certain embodiments, housing 100 further comprises limit ring 130 disposed about interior surface 112 of housing 110 intermediate seal 120 and cone 200. Limit ring 130 is also made of a suitable material and, in currently contemplated embodiments, may comprise 4130 or 4140 alloy steel or the like.

Cone 120 is adapted to accept pipe 12 and be disposed about outer portion 14 of pipe 12 when a outer portion of pipe 12, e.g. exterior surface 14, is disposed within housing 100. In preferred embodiments, cone 200 comprises a material having a yield characteristic matched to a predetermined yield characteristic of pipe 12. Cone 200 is typically disposed at a predetermined position within housing 100 sufficient to be disposed proximate an area of likely pipe buckling of pipe 12 when pipe 12 is inserted into housing 100, e.g. area 15.

In certain contemplated embodiments of flange 10, cone 200 is preloaded in housing 100 under tension, e.g. cone 200 is in hoop tension as that term is understood by those of ordinary skill in these arts.

Additionally, cone 200 is typically adapted to tolerate high dilation strain. In certain embodiments, cone 200 comprises steel having an elongation property in excess of 20%.

Referring additionally to FIG. 2, flange 10 may further comprise slip 300, e.g. as part of flange assembly 10b, where slip 300 further comprises internal teeth 310. At least one surface of a predetermined number of internal teeth 310 may comprise angled grip portion 312. In such embodiments, the angle of angled grip portion 312 may be substantially equivalent to a friction angle sufficient to keep an axial load produced by pipe 12 from exerting a radial load on 200 cone past setting after flange 10 is set.

Slip 300, in currently contemplated embodiments, is made of hardened 4140 or case-hardened 8620/8630 alloy steel or the like. In certain embodiments, slip 300 made from hardened 4140 steel is quenched and tempered hardened whereas slip 300 made from case-hardened 8620/8630 alloy steel is carburized.

Flange 10 may further comprise slip 300 adapted to slidably engage exterior surface 14 of pipe 12 when pipe 12 is inserted into a predetermined portion of housing 100. Slip 300 is typically disposed intermediate cone 200 and exterior surface 14 of pipe 12.

In the operation of a preferred embodiment, referring to FIG. 3, slip engaging pipe 12 may be accomplished by manipulating material strength of cone portion 200 (FIG. 1) of flange 10b (FIG. 1) to its yield point. A predetermined strain characteristic of cone 200 is then manipulated to balance pipe 12 (FIG. 1) to be engaged using repair connector and flange 10 (FIG. 1) made up to pipe 12. In certain currently contemplated methods, cone 200 is loaded in tension.

Slip 300 (FIG. 1) may be positioned in-between cone 200 (FIG. 2) and pipe 12 (FIG. 2). In further embodiments using slip 300, an angle for slip teeth 300 (FIG. 2) may be determined which is substantially equivalent to a friction angle sufficient to keep an axial load produced by pipe 12 from exerting a radial load on cone 200 past setting and slip 300 positioned to engage pipe 12 at the friction angle.

In a further embodiment of slip engaging a pipe, a buckling position within an interior of housing 100 (FIG. 1) at which an inserted pipe, e.g. pipe 12 (FIG. 1), is likely to buckle when pipe 12 is inserted into housing 100 and pipe 12 is under a predetermined load is determined. Cone 200 (FIG. 1), adapted to accept pipe 12 within interior portion 111 (FIG. 1) of housing 100 proximate the buckling position, is disposed within housing 100. In typical embodiments, cone 200 comprises a material having a yield characteristic matched to a yield characteristic of pipe 12. Pipe 12 is inserted into an insertion portion of housing 100, where the insertion portion is at least to the determined buckling position. Cone 200 is engaged about exterior surface 14 (FIG. 1) of pipe 12 proximate the determined buckling position and a material strength of cone 200 manipulated to its yield point. Cone 200 is then allowed to yield rather than pipe 12.

In certain currently contemplated methods, slip 300 (FIG. 1) may be positioned in-between cone 200 (FIG. 1) and pipe 12 (FIG. 1).

Additionally, slip 300 (FIG. 1) may comprise angled slip teeth 310 (FIG. 2) where the angle for slip teeth 310 may be substantially equivalent to a friction angle sufficient to keep an axial load produced by pipe 12 (FIG. 1) from exerting a radial load on cone 200 (FIG. 1) past setting slip 300 positioned to engage pipe 12 at the friction angle.

It will be understood that various changes in the details, materials, and arrangements of the parts which have been described and illustrated above in order to explain the nature of this invention may be made by those skilled in the art without departing from the principle and scope of the invention as recited in the claims.

Claims

1. A coupling for a pipe, comprising:

a. a housing adapted to accept a pipe within an interior portion of the housing; and

b. a cone disposed within the housing, the cone further adapted to accept the pipe and be disposed about an outer portion of the pipe within the housing, the cone comprising a material having a yield characteristic matched to a predetermined yield characteristic of the pipe.

2. The coupling of claim 1, wherein the housing further comprises a seal disposed about an interior surface of the housing, the seal adapted to conform to an outer surface of the pipe inserted at least partially into the housing.

3. The coupling of claim 2, wherein the housing further comprises a limit ring disposed about the interior surface of the housing intermediate the seal and the cone.

4. The coupling of claim 1, wherein the cone is preloaded in the housing under tension.

5. The coupling of claim 4, wherein the wherein the cone is in stable hoop tension.

6. The coupling of claim 1, wherein the cone is adapted to tolerate high dilation strain.

7. The coupling of claim 1, wherein the cone material comprises steel having an elongation property in excess of 20%.

8. The coupling of claim 1, further comprising a slip, the slip further comprising internal teeth disposed about a predetermined surface of the slip to engage a predetermined portion of the pipe when the slip is disposed about the predetermined portion of the pipe.

9. The coupling of claim 8, wherein the slip teeth further comprise at least one angled grip surface portion.

10. The coupling of claim 9, wherein the angle of the angled grip portion is substantially equivalent to a friction angle sufficient to keep an axial load produced by the pipe from exerting a radial load on the cone past setting after the coupling is set.

11. The coupling of claim 1, further comprising a slip ring adapted to slidably engage an exterior surface of the pipe when the pipe is inserted into a predetermined portion of the housing.

12. The coupling of claim 11, wherein the slip ring is disposed intermediate the cone and the exterior surface of the pipe.

13. The coupling of claim 1 wherein the cone is disposed at a predetermined position within the housing sufficient to be disposed proximate an area of likely pipe buckling of the pipe when the pipe is inserted into the housing.

14. A method of slip engaging a pipe, comprising:

a. manipulating material strength of a cone portion of a flange to its yield point;

b. manipulating a predetermined strain characteristic of the cone to balance a pipe to be engaged using the flange;

c. making up the flange to the pipe; and

d. allowing the cone to yield rather than the pipe.

15. The method of claim 14 further comprising loading the cone in tension.

16. The method of claim 15, further comprising positioning a slip in-between the cone and the pipe.

17. The method of claim 16, further comprising:

a. determining an angle for the slip which is substantially equivalent to a friction angle sufficient to keep an axial load produced by the pipe from exerting a radial load on the cone past setting; and

b. positioning the slip to engage the pipe at the friction angle.

18. A method of slip engaging a pipe, comprising:

a. determining a buckling position within an interior of a housing at which a pipe is likely to buckle when the pipe is inserted into the housing and the pipe is under a predetermined load;

b. disposing a cone adapted to accept the pipe within the interior of the housing proximate the buckling position, the cone comprising a material having a yield characteristic matched to a yield characteristic of the pipe;

c. inserting a pipe into an insertion portion of the housing, the insertion portion being at least to the buckling position;

d. engaging the cone about an exterior surface of the pipe proximate the buckling position;

e. manipulating a material strength of the cone to its yield point;

f. manipulating a predetermined strain characteristic of the cone to balance the engaged pipe; and

g. allowing the cone to yield rather than the pipe.

19. The method of claim 18, further comprising positioning a slip in-between the cone and the pipe.

20. The method of claim 19, further comprising:

a. determining an angle for the slip which is substantially equivalent to a friction angle sufficient to keep an axial load produced by the pipe from exerting a radial load on the cone past setting; and

b. positioning the slip to engage the pipe at the friction angle.