GB2233415A

GB2233415A - Pipe connectors

Info

Publication number: GB2233415A
Application number: GB9010951A
Authority: GB
Inventors: George David Lemons
Original assignee: FMC Corp
Current assignee: FMC Corp
Priority date: 1989-06-30
Filing date: 1990-05-16
Publication date: 1991-01-09
Anticipated expiration: 2010-05-16
Also published as: JPH0341286A; AU5575590A; GB2233415B; JPH0781656B2; NO301135B1; FR2649175A1; DE4016124C2; NL193117C; FR2649175B1; AU629935B2; CA2016566C; DE4016124A1; NL193117B; NO902222L; CA2016566A1; NL9001167A; BR9002331A; NO902222D0; GB9010951D0; IT9020386A1

Abstract

A pipe connection 9a comprises a first and a second pipe element 10, 11 each including a cavity 30, 36 adjacent to a center bore 31, 32 in the pipe element. The first pipe element 10 has a substantially smooth inner surface which defines an outer boundary of the first cavity 30. An annular seal 26a mounted in the cavities seals the junction between the pipe elements. An outer portion of the seal has a plurality of ridges or threads 40 having outer points 42 which press against the inner surface of the first cavity to retain the annular seal in the first cavity when the pipe elements are separated. <IMAGE>

Description

1 PIPE CONNECTIONS

BACKGROUND OE THE INVENTION

This invention relates to pipe connections, and more particularly, to such connections for use in temporary and quasi-permanent pipe flowlines.

Temporary and permanent flowlines are commonly used in production, drilling, cementing, stimulation, injection and testing of oil and gas wells. Flexible devices with quick connections at the ends provide a quick and convenient layout of the piping system and provide fluid tight seals between the mating pipe element members. Some of the flexible devices used are swivel joints, hoses, composite structure pipe, and ball joints. Seals and separate connections are required at each end of the device. Connections include hammer type unions, flanges, clamps, specialty couplings, and pipe threads.

SUMMARY OF THE INVENTION

The present invention provides a pipe connection comprising:- first and second pipe elements, respectively having axially extending bores and end portions provided with first and second respective cavities adjacent to said bores; and an annular seal for mounting in said first and second cavities to prevent leakage at a joint between said pipe elements, said seal including an outer portion provided with protruding surface formations which press against an inner surface of the first cavity to retain the annular seal therein when the first and second pipe elements are separated.

The pipe connection may serve e.g. as a swivel joint or as a pipe connector. This reduces the number of seal leak paths in the total piping system; reduces the number of variations in pipe elements required; enhances the utility of individual pipe elements; and reduces the cost of pipe elements required. In a preferred embodiment, a pair of pipe retention members each have an internal bore for receiving one of a pair of pipe elements. Each of the retention members is 2 secured to a corresponding one of the pipe elements by a load element, such as a load ring. The retention members are interconnected by pipe threads or other means to secure the pipe elements in a f ixed end-to-end relationship. The retention members can be interconnected with the pipe elements positioned a distance apart and the retention members rotated relative to each other to pull the pipe elements into tight alignment. The retention members can be readily disconnected from the pipe elements by merely removing the load elements and the retention members removed from the pipe elements.

The pipe elements each have a central bore extending lengthwise through the pipe element and each element has a cavity adjacent to the central bore. A first one of the pipe elements includes an inner surface defining an outer boundary of its cavity. An annular seal is mounted in the two cavities when the pipe elements are connected, with the seal extending along a portion of the lengths of the two pipe elements adjacent to an end portion of each of the pipe elements. Thus, the seal extends across a junction of the pipe elements to prevent leakage at a joint between the pipe elements. The annular seal includes an outer portion having a plurality of protruding surface formations which press against the inner surface of the cavity in the f irst pipe element. The seal can be pressed into the cavity causing the frmations of the seal to press against the surf ace of the cavity of the f irst pipe so the seal remains in the cavity when the two pipe elements are separated, thereby preventing dropping and losing the seal. The annular seal and its formations have an outer diameter slightly larger than the diameter of the cavity so an outer portion of the formations presses tightly against the inner surface which def ines the outer boundary of the cavity. When a pair of threaded nuts are used as the retention members the joined pipe elements can be identical thereby reducing the number of different elements to be manufactured. The profile of the pipe elements of the present invention is small compared to unions and similar devices in prior art connectors.

Other features and advantages of the invention will be 3 apparent from the claims and from the following description, made with reference to the drawings.

BRIEF-DESCRIPTION OE THE DRAWINGS

Figure 1 is a side elevation. partly in section, of one embodiment of a pipe connection of the present invention.

Figure 2 is an end section of the pipe connection of Figure 1 taken along line 2-2 of Figure 1.

Figures 3-6 are partial sections of another embodiment of the pipe connection of Figure 1 showing a sequence of disconnecting the pipe elements.

Figure 7 is an enlarged side elevation, partly in section of the pipe connection of Figures 3-6, showing details of a threaded portion of the annular seal and of the cavity.

Figure 8 is a further enlarged inside elevation of one embodiment of a portion of the threaded seal of Figure 7.

Figure 9 is another embodiment of the threaded seal of Figure 8.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Figures 1, 2 disclose a pipe connector device 9 having a pair of pipe elements 10, 11 interconnected by a pair of retention members 12, 13 and a pair of load elements 17. Pipe elements 10, 11 are mounted in an internal bore 12a, 13a. of the retention members 12, 13 and secured to members 12, 13 by load elements 17, each mounted in a pair of grooves 18a, 18b and 18c, 18d.

To assemble connector device 9, member 12 is positioned about pipe element 10 with groove 18a adjacent to groove 18b and member 13 is positioned about pipe element 11 with groove 18c adjacent to groove 18d. A plug 19 is removed from a bore 20 of member 12 and a plurality of load elements 17 are fed through bore 20 into grooves 18a, 18b to secure member 12 to pipe element 10 and plug 19 is replaced in bore 20. A plug 24 is removed from a bore 25 and a plurality of load elements 17 are fed through bore 25 into grooves 18c, 18d to secure member 13 to pipe element 11. Plug 24 is replaced in bore 25 to keep load elements 17 in place. A sealing member 26 provided with protruding surface formations (not shown) is placed in a portion of a cavity 30 adjacent to a center bore 31 of pipe 4 element 10. Pipe elements 10, 11 are positioned with center bore 31 of pipe element 10 aligned with a center bore 32 of pipe element 11. Member 12 is rotated relative to member 13 so that a threaded portion 12b of member 12 mates with a threaded portion 13b of member 13 and draws pipe elements 10, 11 toward the position shown in Figure 1. A portion of sealing member 26 moves into a cavity 36 adjacent to center bore 32 and the portion of sealing member 26 provided with surface formations is pressed into the cavity 30 to provide a fluid tight seal between elements 10 and 11. Groove 18c is wider than groove 18d so that retention members 12, 13 can be partially threaded together before a rotation of member 12 relative to member 13 applies pressure to secure pipe elements 10, 11 in tight abutment. Engagement of the surface formations within the cavity 30 retains the sealing element therein upon separation of the pipe elements.

Another embodiment of the present invention 9a disclosed in Figures 3-6 includes another wide groove 18e in retention member 12d. Plugs 19, 24, disclosed in Figures 1, 2, have been omitted from Figures 3-6 in order to simplify the drawings but it should be understood that such plugs are needed to install the load elements 17a, 17b.

When it is desired to disconnect pipe element 10 from pipe element 11, to replace seal 26 or for other reasons, member 12d is rotated relative to member 13 causing the members 12d, 13 to be spaced as shown in Figure 4. Further rotation of member 12d relative to member 13 causes a shoulder 37 of groove 18e to press against a load- element 17a and a shoulder 38 of groove 18c to press against a load element 17b to move pipe element 10 away from pipe element 11 as shown in Figure 5. The slight separation of elements 10, 11 allows any internal pressure in bores 31, 32 to bleed off while threads 12b, 13b are still engaged and prevent elements 10, 11 from being blown apart. Still further rotation of retention member 12d allows pipe elements 10, 11 to be separated as shown in Figure 6.

The forced separation of pipe elements 10, 11 due to rotation of members 12, 13 prevents elements 10,11 from 4 sticking together and facilitates seal replacement or dismantling of flowline systems.

In the embodiments disclosed in Figures 1-6 pipe elements 10, 11 are identical which simplifies manufacturing and reduces costs compared to connectors using unlike pipe elements. The load elements 17, 17a, 17b can also be identical to reduce costs.

Details of seal 26a for use in the connector devices 9, 9a is disclosed in the enlarged drawing of Figure 7. A r idged outer portion 26b of seal 26a is pressed against a substantially smooth inner surface 30b of cavity 30 to secure seal 26a to pipe element 10 when pipe elements 10 and 11 are separated. This prevents seal 26a from being dropped and possibly lost when retention members 12d, 13 are separated. The right hand portion (Figs. 3, 7) of seal 26a is positioned in cavity 30 and the left hand portion of seal 26a is in cavity 36 when pipe elements 10,11 are locked together as shown in Figure 3. Since load elements 17 are locked into grooves 18a-18d this embodiment has no loose pieces when members 12, 13 are separated. When seal 26a needs to be replaced, member 12d is rotated relative to member 13 until members 12d, 13 are separated, seal 26a being retained in the cavity 30 by the ridged portion 26b. Seal 26a is then pulled axially away from center bore 31 until ridged portion 26b disengages from surface 30b of cavity 30. A new seal 26a is pushed into cavity 30 and retention member 12d rotated relative to retention member 13 to reconnect the pipe elements in a fluid-tight arrangement.

A plurality of ridges 40 (Fig. 8) are formed on seal 26a so they tilt toward a center groove 41 to facilitate moving seal 26a into cavity 30 (Fig. 7) with ridges 40 pressed against surface 30b of cavity 30. This tilt also causes a plurality of radially outer points 42 to press even more firmly against surface 30b when seal 26a attempts to move from right to left in cavity 30. A diameter D1 of seal 26a is slightly (0.00111 to 0. 00511, 0.025 to 0.127 mm) greater than a diameter D2 of cavity 30 to insure a tight fit of seal 26a in cavity 30. Ridges 40 can be spiral threads of the type used p 6 on bolts or ridges 40 can be annular, arranged in axial succession. other forms of protrusions will also be apparent. An advantage of the spiral threads is they can be formed using a conventional thread die of the type used on large bolts. The thread die also provides accurate values of diameter to outer points 42 of seal 26a at a low cost. An advantage of having ridges which are annular is easier replacement of seals 26a. Annular ridged seals remain close to the center 46 of cavity 30 (Fig. 7) as they are being removed, while spiral threads may cause seal 26a to be forced away from the center line of cavity 30 and bind against surface 30b of cavity 30.

If greater holding power is desired the tilt of the threads or ridges may be increased as shown in a plurality of threads 40a (Fig. g). The outer points 42 of threads 40 (Fig. 8) and 40a (Fig. 9) bend slightly when seal 26a is forced into cavity 30 (Fig. 7).

The present invention may be used in a connection having few parts, e.g. a swivel joint or a pipe connector. A seal is attached to one pipe element to prevent dropping the seal when a pair of pipe elements are separated. Other elements are preferably also secured to the pipe elements to prevent loose pieces from being dropped or lost.

Although the best mode contemplated for carrying out the present invention has been herein shown and described, it will be apparent that modification and variation may be made without departing from what is regarded to be the subject matter of the invention.

7

Claims

CLAIMS:

1. A pipe connection comprising:- first and second pipe elements, respectively having axially extending bores and end portions provided with f irst and second respective cavities adjacent to said bores; and an-annular seal for mounting in said first and second cavities to prevent leakage at a joint between said pipe elements, said seal including an outer portion provided with protruding surf ace formations which press against an inner surface of the first cavity to retain the annular seal therein when the first and second pipe elements are separated.

2. A pipe connection as claimed in claim 1 wherein the first and second cavities have substantially smooth surfaces defining their radially outer boundaries and extend axially along a portion of the lengths of the first and second pipe elements.

3. A pipe connection as claimed in claim 1 or 2 wherein a diameter of the annular seal is greater than a diameter of the first cavity whereby the protruding surface formations are forcibly pressed against the inner surface of the first cavity to retain the seal therein.

4. A pipe connection as claimed in claim 1, 2 or 3 wherein the surface formations are ridges having an outer point which is tilted relative to the seal to facilitate moving the seal into the first cavity and to increase the resistance of the seal against removal from the first cavity.

5. A pipe connection as claimed in claim 4 wherein the ridges extend annularly about the seal in axial succession.

6. A pipe connection as claimed in claim 4 wherein the ridges are in the form of a spiral threaded area on the outer surface of the seal.

A 8

7. A pipe connection substantially as described with reference to or as shown in the drawings.

Published 1991 at The Patent Office. State House. 66171 High Holbom,1. ondonWCIR47?. Further copies maybe obtained from The Patent Office $ales Branch. St Mary Cray. Orpington. Kent BR5 3RD. Printed by Multiplex techniques ltd. St Ma-ry Cray. Kent. Con. 1187