Cross-Reference to Related Applications

fOOOIJ Priority is claimed to U.S. provisional application No. 01/775.749, filed March 1 .! _» 2013. the disclosure of which is. incorporated herein by reference in its entirely.

Field of the Invention

ΙΌ0Θ2] The field of the present invention is systems and methods for joining lined pipes, and particularly cement or rubber lined pipes.

Background of the Invention

[0003] Within industries that use lined pipes, among which is the mining industry; steel pipe is manufactured and may be installed for multiple purposes. Steel pipe can be connected or joined in a variety of ways depending on the application and design requirements. One of the struggles that currently exists with pipes having internal cement or rubber linings is obtaining quality welds when connecting two pieces of beveled end steel cement-lined or rubber-lined pipe. Currentl when two sections of pipe are joined together, beveled end against beveled end, and the initial weld pass (referred to as the "root pass") directly contacts the cement or rubber lining, resulting in both contamination of the welding and weakening of the cement or mbber during the root pass. The result is that the completed weld joint strength is reduced due to this contamination. Also this joint type does not allow a quality mechanical or nondestructive test of the completed welded joint.

ΙΌ0Θ4] In order to overcome this problem with concrete contamination, the thickness of the pipe wall has been increased by about 20% or greater than necessary fo most applications. Such a solution results in about a 20% or greater mcrease in the cost of materials. A more cost effective solution to preventing concrete contamination when joining lined pipes by welding is therefore desired.

Summary of the Invention

jOeoS] The present invention is directed toward a lined pipe and a system and method for joining such lined pipes. The pipes may be cement-lined or rubber-lined carbon steel pipes, although those of skill in the art may recognize uses for the system wit other types of pipe and with other types of lining.

[0006] in a first separate aspect of the present invention, a ring is disposed within and substantially flush with the end of a pipe having an interior lining covering substantially all of the interior wai! of the pipe. The ring forms a circumferential pressure seai against the interior wal l of the pipe, and the radial thickness of the interior lining and the first ring are substantially the same.

[8007] In a second separate aspect of the present invention, the system i ncludes two pipes joined end-to-end, each pipe having an interior lining covering substantially all of the interior wall of the respective pipe. One of two rings is disposed within the joined end of each pipe, with each ring being substantially flush with the respective joined end. Both rings are configured to create a circumferential pressure seal against the interior wail of the respective pipe, in addition, at least one of the rings is configured to create a pipe joint pressure seal against the other of the rings.

{ ^' 0008] Several different enhancements ma be incorporated into this system, either alone or in combination with other enhancements, As one enhancement, the radial thickness of each ring may be approximately the same as the radial thickness of the lining of each respective pipe. As another enhancement, The circumferential pressure seals may be formed by an O-ring set in a circumferential groove in the outer circumferential surface of the ring, or they may be formed by a weld. As another enhancement, the inner circumferential surfaces of the rings may include a coating configured to resist corrosion when exposed to a fluid transported within the pipe during use.

{ ^' 0009] In a third separate aspect of the present invention, a method of connecting lined pipes includes inserting one of two rings into the respective ends of two pipes to be joined end-to-end. Each ring is inserted so that, it is substantially flush with the end of the respective pipe, and each ring forms a circumferential pressure seal against the interior wall of the respective pipe. With the rings inserted, the two pipe ends are welded together along an. exterior circumference of the pipes. This method may be enhanced by use of a two piece clamp configured to seat the rings within the ends of the respective pipes as the two clamp pieces are drawn together. [0010] I n an fourth separate aspect of the present in vention, any of the foregoing aspects may be employed in combination.

[001 Ί J Accordingly, an improved joint lock ring system is disclosed. Advantages of the improvements will be apparent from the drawings and the description of the preferred embodiment.

Brief Desert prion of the Drawings

J00 2J The foregoing summary, as well as the following detailed description of the exemplary embodiments, will be better understood when read in conjunction with the appended drawings. It should be understood, however, that the invention is not limiied to the precise arrangements and instrumentalities shown in the following figures:

[0013] Figs. 1A-E illustrate a first joint lock ring system;

|0014 j Figs. 2A-C illustrate a second joint lock ring system;

[0015 j Figs. 3A-C illustrate a third joint Sock ring system;

[0016] Figs. A-B illustrate a fourth joint lock ring system;

[0017] Figs. 5A-D illustrate a fifth joint lock ring system;

[0018] Figs. 6A-C illustrate a sixth joint Sock ring system;

[0019] Figs. 7A-D illustrate a first half of a pipe clamp assembly ;

(0020] Figs. SA-C illustrate a second half of a pipe clamp assembly; and

[0021] Figs. A~D illustrate an alternative embodiment of the first half of the pipe clamp assembly.

Detailed Description of the invention

[0022] Turning in detail to the drawings, Figs. 1A-E illustrate a joint lock ring system 1.01 suitable for use wit a cement lined pipe 103. A cement lined pipe is described herein as an exemplified embodiment, and those of skill in the art will recognize that the same system may be used with any type of lined pipe, whether the lining be formed by cement; rubber, or any other materials. Thus, it is to be understood that The system includes two rings 105, 107, each inserted into the respective ends 109, 111 of the cement lined pipes 103, each ring being flush with the respective end of the pipe. The cement lining 1 13 lines the inner wall 1 14 of the pipes 103 between the rings 105, 107. Each ring 105, 107 is preferably formed from carbon steel, and preferably of the same steel grade and properties as the pipe, that is roiled to a specified diameter and machined to a speci fied tolerance. The diameter and tolerance are a matter of design choice, depending upon the size and wail thickness of the pipe into which the ring is to be placed.

(0023) Each ring 105. 107 includes a circumferential groove i l 5 in the outer circumferential surface 1 1.7, into which is placed an O-tirig .1 1 , which seals against the internal pipe wall 1 14. This first O-Ring 1 19 restricts fluid, within the pipe from reaching or affecting the weld zone of the welded joint 1 1. The first ring 105 includes an anterior side circumferential groove 123 in which another O-ring 1.25 is seated. This second O- ring 125 creates a pipe joint pressure seal against the second ring 107, as shown in Fig. 1 A, when the pipes 103 are aligned and welded together, and it likewise restricts fluid within the pipe from reaching or affecting the weld, zone of the welded joint 121. The O- rings are preferably formed from a fTuoroearbon elastomer rubber, such as the Viton® brand sold by E.J. da Pont de Nemours and Company of Wilmington, DE.

{ ^' 0024] The anterior side O-ring locations are expected to hold line pressure in excess of 2000 PSi in the event of a weld failure. The benefit provided is a duai sealing systeni thai prevents fluids from potentially escaping into the environment in the event of a weld failure.

{0025] Internal surfaces 127 of the rings 105. 107 that, contact the fluid within the pipes are coated with a wear resistant, nors -conductive ceramic coating 129. This coating 126 preferabl extends entirely along the entire posterior surface 131 of the rings 105, 107 and partially along the anterior surface 133, at least to approximately where the O-ring 1 19 contacts the anterior surfaces 133 of each ring 105, 107 to form the pipe joint pressure seal. Preferably, an aluminum oxide, A1203 (such as is available from Accuratus Corporation of Phillipsburg. J), coating is applied by a plasma spray process to a thickness of about 15 mils to 20 mils. Such a coating is highly resistant, to abrasion, heat, and corrosion.

{0026] A second joint lock ring system 201 is illustrated in Figs, 2A-C. This second system 201 is like the first, except for instead of an O-ring being placed in the side Circumferential groove 1 15 of the first ring 105, a flat, flexible gasket 205 is placed therein. This flat flexible gasket is preferably of the type obtainable from Garlock Sealing Technologies of Palmyra, NY, particularly the Garlock BLUE-GARD 3400 model of flexible gasket.

| 027] A third joint lock ring system 301 is illustrated in Figs. 3A-C. T is third system 301 is also like the first, except for this system 301 does not include a protective ceramic coating, and instead of an O-ring being placed in the side circumferential groove of a ring, the inner surface 305 of each ring 303 is formed with one or more interlocking grooves 307. These interlocking grooves 307 are formed to be complementary to similar interlocking grooves 309 formed on a protective circumferential liner 31 1 , which is preferably molded with Vtton® fiuorocarboii elastomer rubber. The interlocking grooves 307 of each ring 303 and the interlocking grooves 309 of each liner 31 1 may take a shape according to design preference, with the purpose being that the respective grooves 307, 309 serve to hold the liner in place on the inner surface 305 of the ring 303. The anterior and posterior edges 313, 315 of each liner 31 1 extends slightly beyond the edge of the ring 303 so that a seal can be created with the cement liner on one edge 13 and with the second ring on the other edge 315, These sealing points prevent fluids from potentially escaping into the environment in the event of weld failure.

{0028} A fourth joint lock ring system 401 is illustrated in Figs. 4A-E. This fourth system 401 incorporates features of both the first system and the second, system, in this fourth system 401 , the first ring 403 includes an anterior side circumferential groove 407 in which an O-ring 409 is seated, and a liner 41 1 , which is again preferably molded with Viton® fiuorocarbon elastomer rubber, is affixed the inner surface 413 of each ring 403, 405. Through holes 415 are formed around each ring 403, 405, the liner 41 1 extends into the through holes. The through holes 415 are formed to have varying diameters, and the liner 411 is formed with fingers 437 having a complementary shape as compared to the through holes 415 to aid in holding the liner 41 1 in place on each ring 403, 405. The liner 41 1 covers the entire posterior edge 419 of each ring 403, 405 so that a bonded seal can be created with the cement or rubber liner adjacent the posterior edge 419, This sealing point prevents fluids .from potentially escaping into the environment in the event of a weld failure.

{0029} A fifth joint lock ring system 501 is illustrated in Figs. 5A~D. In this fifth system 501, the first ring 503 may be similar to any of the rings described above in Figs. 1A and 2A. The second ring- 505 includes a. circumferential flanae 507 that extends between the cement lining 509 and the pipe 51.1. The end 51.3 of the flange 507 i s affixed to the inner pipe wall 515 by a. weld 516, before the lining is placed, to form a pressure seal and to hold the ring 505 in place. Both rings 503. 505 include a ceramic coating 517, The Q-ring that is used to create the pipe joint pressure seal may be located on either ting, as it is shown in Fig. 5C as bing on the first ring 503, and it is shown in Fig. 5D as being on the second ring 505a. This type of ring with a flange is particularly useful for curved pipe, tees, ells, reducers, and other non-linear pipe sections.

{ ^' 0030] A sixth joint lock ring system 601 is illustrated in Figs. 6A-C. In this sixth system 601 , both rings 603, 605 are similar to the second ring depicted in Figs, 5A-C. Both rings include a circumferential flange 607 which extends between the cement lining 609 and the interior walls 6.13 of the pipes 611 , each circumferential flange 607 being affixed to the interior wail 613 of the respective pipe 1 1 by a weld 615, which forms a pressure seal to prevent leakage in the event the weld between the two pipes fails. This type of system is particularly useful for retrofitting lined pipes in the field,

f 00311 During the manufacture process, the rings are manufactured to meet the intended use conditions for the pipe, and the internal lining requirements for the intended use are determined. The rings are first installed into each end of the pipe at the manufacturing plant, after which the pipe then goes through a machine powered centrifugal cement lining process, such as is well known in the cement-lined pipe industry.

}0032) At the manufacturing plant customer specified, lengths of steel pipe have their interna! ends ground with a .040 chamfer and any excess internal weld seam is sanded smooth. Rings according to a customer's specificatio are fitted with O-rings in the amoves on the outer circumferential surfaces of each ring. A non-toxic, non-petroleum base lubrication is applied to the inside end of the pipe. The ring is then pressed into position. Once the ring is in place, four one inch long tack welds are applied to the back side of the ring. This procedure is repeated for each end of the pipe. G The pipe is then loaded into the cement lining machine, in which cement slurry is pumped into the pipe from one end t the other. The pipe is rolled into the machine and spun ai an appropriate rate to centrifugaly compact the lining to the predetermined thickness and quality. Since the inserted ring was machined to match the required thickness of the applied cement lining, and overall smooth interior surface of the pipe is formed by compressing the cement lining against the end of each ring, creating a seal and bond to the pipe and the inserted ring. The pipe is removed from the machine, hand finished and capped to go through the curing process. After the cement is cured and reaches its designed strength the pipe section is ready for shipping to the customer for installation.

10033] Although the embodiments above are presented from the perspective of the ring systems being placed at the time of manufacture, it is possible, albeit somewhat labor intensive, to place the rings in the field when a pipe needs to be cut to a shorter length. In the field, after the pipe is cut to length, the next step is remove sufficient amount of the cement lining to allow the ring to be placed into the cut end of the pipe. Removal of at least 1-2 cm extra of the lining is preferred. With the cement lining partially removed, and the cut end of the pipe otherwise prepared to receive the ring by removal of buns and sharp edges, the two-piece clamp shown in Figs. 7A-D and SA-C are used to position the ring within the end of the cut pipe. The first clamp part 701 shown in Figs. 7A-D includes two halves 703, 705, which are affixed to the end of the cut pipe using holes 707 in flanges 709 to clamp the two halves 703, 705 aroimd the outer wall of the cut pipe end. The first flange part 701 also includes at least 4 other clamp flanges 713, with holes 715, which are used to secure the first clamp part 701 to the second clamp part 717. Preferably, the first clamp part 701 i positioned to have one edge approximatel flush with the cut end of the pipe, with the guide flanges 71 1 extending away from the cut end of the pipe to support ring being inserted into the pipe, in alternative embodiments more guide flanges may be included, or they may be excluded altogether. With the first clamp part 701 affixed to the cut end of the pipe, the ring is partially seated within the cut end as far as it can be inserted by hand, which will typically be at the point where the O-ring is pressed up against the cut end of the pipe. With the ring partially seated, the second clamp part 717 is secured to the first clamp part by aligning the four peripiiemi holes 71 on the second clamp part. 717 with the four holes 715 on the first clamp part 701 and inserting bolts through the holes 715 in tire first clamp part 701 to engage the peripheral holes 71 (whic may be threaded, or a nut may be used) of the second clamp part 717, The second clamp part 717 is then drawn toward the first clamp part 7 1 by tightening the bolts, and the second c!amp part 717 will subsequently press the ring in to the cut end of the pipe by compressing the O-ring. Once the ring is fully seated, approximately flush with the cut end of the pipe, the 0~ring will create the desired seal, as described above. As a last step, prior to welding the cut pipe to another pipe, is to fill in the space left between the edge of the cement lining and the now-seated ring with appropriate cement for the intended use of the pipe.

{0034J Figs. 9A-D illustrate an alternative embodiment of the first ciamp part 90 i . This clamp part is similar to the first clamp part shown in Figs. 7A-D, with the addition of stabilizing flanges 903 which are placed extending along the exterior surface of the pipe. These stabilizing flanges 903 aid in placement of the first clamp part on the pipe, helping to ensure that the bolts of the first clamp part are aligned with the longitudinal ax is of the pipe.

{0035] Two sections of pipe are joined by placing them end to end in preparatio for welding. An for rings with a side circumferential groove, and O-ring or flexible gasket is placed into the side circumferential groove, and two of the first clamp parts, shown in Figs. SA-D, are used to draw the two sections of pipe together and compress the O-ring or gasket between the ring surfaces. The join may then be tack welded in preparation for the complete welding of the two pipe sections. Each pipe joint is connected in the same manner. The weld joints formed in this manner may undergo nondestructive weld testing and the final quality control examination, without concern of cement inclusion or further weakening the cement lining.

{0036) Some of the benefits that may be realized from the joint lock ring systems described above include;

} ^' 0037] · Allows for full penetration joint welding with no internal cement or rubber lining contamination in the weld zone.

{00383 * Allows for mechanical and non destructive testing of the finished weld joint. J0039] * Allows for a reduction in pipe wail thickness and weld time over partial joint penetration designs.

{ ^' 0040] * Replaces a challenged industry standard for cement lined pipe joining.

{0041] * Accomplishes a permanent inside pipe shoulder for cement lining containment and protection that is out of the weld zone, and no cement patching is required before or after the joint welding for factory installed rings. { ^' 0042] * The rings can be factory installed in all straight pipe and loose fittings to be butt welded in the field.

[0043] · The rings can be easily installed m the field after cutting and beveling the pipe.

{ ^' 0044] · Shop quality internal cement lining patches can be accomplished by □installation crews for all "cut to fit" field joint applications.

f00 5| · Some designs of the ring system utilize an 0~ring gasket, that provides a secondary pressure seal that will safe guard the environment [Jin the event of a weld failure.

{ ^' 0046] · The rings can be used with all designs of cement and mbber linings.

[0047] * The ring base material. ID coatings, and O-ring seal can be O engineered and adapted to .meet specific pipe grades, various service conditions, and fluid types.

{00483 Thus, a joint lock ring system is disclosed. While embodiments of this invention have been shown and described, it will be apparent to those skilled in the art that many more modifications are possible without departing from the inventive concepts herein. The invention, therefore, is not to be restricted except in the spirit of the following claims.