CA1040230A - Flexible sealing joint - Google Patents
Flexible sealing jointInfo
- Publication number
- CA1040230A CA1040230A CA261,915A CA261915A CA1040230A CA 1040230 A CA1040230 A CA 1040230A CA 261915 A CA261915 A CA 261915A CA 1040230 A CA1040230 A CA 1040230A
- Authority
- CA
- Canada
- Prior art keywords
- flexible element
- annular
- elastomer
- fluid
- rings
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 238000007789 sealing Methods 0.000 title claims description 6
- 229920001971 elastomer Polymers 0.000 claims abstract description 68
- 239000000806 elastomer Substances 0.000 claims abstract description 68
- 239000012530 fluid Substances 0.000 claims abstract description 35
- 230000007423 decrease Effects 0.000 claims abstract description 14
- 239000000463 material Substances 0.000 claims description 12
- 230000004044 response Effects 0.000 claims description 8
- 230000006872 improvement Effects 0.000 claims description 4
- 239000013536 elastomeric material Substances 0.000 claims description 3
- 238000005553 drilling Methods 0.000 description 20
- 229910052751 metal Inorganic materials 0.000 description 9
- 239000002184 metal Substances 0.000 description 9
- 230000009471 action Effects 0.000 description 6
- 230000000712 assembly Effects 0.000 description 3
- 238000000429 assembly Methods 0.000 description 3
- 238000007906 compression Methods 0.000 description 3
- 101100536354 Drosophila melanogaster tant gene Proteins 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 2
- 230000006835 compression Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000007667 floating Methods 0.000 description 2
- 238000003475 lamination Methods 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000036316 preload Effects 0.000 description 2
- 239000013535 sea water Substances 0.000 description 2
- 239000010959 steel Substances 0.000 description 2
- 241000905957 Channa melasoma Species 0.000 description 1
- 244000043261 Hevea brasiliensis Species 0.000 description 1
- 102000006835 Lamins Human genes 0.000 description 1
- 108010047294 Lamins Proteins 0.000 description 1
- 208000036366 Sensation of pressure Diseases 0.000 description 1
- 229910052729 chemical element Inorganic materials 0.000 description 1
- 230000000295 complement effect Effects 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
- 210000005053 lamin Anatomy 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 229920003052 natural elastomer Polymers 0.000 description 1
- 229920001194 natural rubber Polymers 0.000 description 1
- 239000002674 ointment Substances 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 239000002990 reinforced plastic Substances 0.000 description 1
- 230000008439 repair process Effects 0.000 description 1
- 239000012858 resilient material Substances 0.000 description 1
- 230000000717 retained effect Effects 0.000 description 1
- 239000005060 rubber Substances 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 238000010008 shearing Methods 0.000 description 1
- 229920003051 synthetic elastomer Polymers 0.000 description 1
- 239000005061 synthetic rubber Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
- -1 ~iberglass Substances 0.000 description 1
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
- F16L27/00—Adjustable joints, Joints allowing movement
- F16L27/10—Adjustable joints, Joints allowing movement comprising a flexible connection only, e.g. for damping vibrations
- F16L27/103—Adjustable joints, Joints allowing movement comprising a flexible connection only, e.g. for damping vibrations in which a flexible element, e.g. a rubber-metal laminate, which undergoes constraints consisting of shear and flexure, is sandwiched between partly curved surfaces
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B17/00—Drilling rods or pipes; Flexible drill strings; Kellies; Drill collars; Sucker rods; Cables; Casings; Tubings
- E21B17/02—Couplings; joints
- E21B17/08—Casing joints
- E21B17/085—Riser connections
Landscapes
- Engineering & Computer Science (AREA)
- Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Mining & Mineral Resources (AREA)
- Mechanical Engineering (AREA)
- Physics & Mathematics (AREA)
- Environmental & Geological Engineering (AREA)
- Fluid Mechanics (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- General Engineering & Computer Science (AREA)
- Joints Allowing Movement (AREA)
Abstract
Abstract A flexible joint for a conduit transporting fluid under pressure includes a pair of spaced rigid rings. An annular flexible element is disposed between and sealingly engaging the rings so as to define a pair of annular exposed side surfaces on the element. One side surface is exposed to pressurized fluid flowing through the conduit, thereby creating a pressure differential across the flexible element between its side surfaces. To resist the load that results from the pressure differential, the flexible element in-corporates a body of elastomer that has a thickness between the rings which decreases from the one side surface of the element to the other side surface. The flexible element can thus resiliently accommodate relative motion between the rings, while providing a fluid-tight, pressure-resistant seal.
Description
In recent years, succes~ful methods have been developed for drilling oil and gas wells at underwater locations. A~ a result, an oil or gas well may be drilled and completed 90 that the entire wellhead assembly i~ posi-tioned at a depth at least sufficient to avoid being anavigation hazard to ocean-going vessels (e.g., at or near the ocean floor). Such orfshore or underwater wells may be dri~d from a vessel, such as a drilling barge, or from a platform mounted on legs extending downwardly to the ocean floor.
A drilling barge or similar ~essel i9 particularly susceptible to movements in response to wave action, even though the barge is anchored. Drilling that ls done from a floating vessel must accommodate both lateral and vertical movements of the ve~sel. Accordingly, drilling equipment such as drilling strings and riser lines, which extend down-wardly from the drilling ves~el to the ocean floor, must possess a degree of flexibility sufficient to prevent rupture when the drilling ve~sel moves slightly from its designated location. Typically, the pipe in a drilling string i9 of a su~ficiently small diameter and has su~ficient strength to be flexlble enough to avoid damage. The riser line or marine conductor pipe, on the other hand, has a relatively large diameter and encloses the drilling string 80 that drilling ~mud" may be returned upwardly in the annulus between the inner wall of the riser pipe and the outer wall of the drill string. The increased diameter and rigidlty o~
the riser pipe, as compared to the drill string, requires that the rise pipe include at least one coupling or ~oint assembly that can be readily flexed, can withstand high internal and external fluid pressures, and can hold up
A drilling barge or similar ~essel i9 particularly susceptible to movements in response to wave action, even though the barge is anchored. Drilling that ls done from a floating vessel must accommodate both lateral and vertical movements of the ve~sel. Accordingly, drilling equipment such as drilling strings and riser lines, which extend down-wardly from the drilling ves~el to the ocean floor, must possess a degree of flexibility sufficient to prevent rupture when the drilling ve~sel moves slightly from its designated location. Typically, the pipe in a drilling string i9 of a su~ficiently small diameter and has su~ficient strength to be flexlble enough to avoid damage. The riser line or marine conductor pipe, on the other hand, has a relatively large diameter and encloses the drilling string 80 that drilling ~mud" may be returned upwardly in the annulus between the inner wall of the riser pipe and the outer wall of the drill string. The increased diameter and rigidlty o~
the riser pipe, as compared to the drill string, requires that the rise pipe include at least one coupling or ~oint assembly that can be readily flexed, can withstand high internal and external fluid pressures, and can hold up
-2--~ -3-under the ~brasive action Or fluids, well tool~ and other objects that pass through the ri~er pipe.
One type of flexible ~oint used in ri~er pipes consists of a ball member having a precisely machined spherical surface and a socket member ha~ing a complementary, precisely machined 3pherical surface. The ~oint is flexed by sliding one o~ the spherical surfaces relative to the other. Resilient O-rings help ~eal the Joint at the interface between the slid-ing sur~aces. The flexural movement of such a ball joint i9 impaired, however, when the Joint is ~ub~ected to high pres-sures. The ~oint is al90 subJect to ~rictional wear and deterioration o~ both the slidine surfaces and the O-ring seals, which requires frequent repair or replacement of the ~oint.
Another type of flexible joint for fluid conduit~, such as marine riser pipes, utilizes annular flexible ele-ments disposea between flanges secured to adJaoent ends of different ~ections of condu~t. The ~lexible elements ¢omprise alternating layers of a rigid and a resilient material, uhich are normally metal and an elastomer. The layers or lamina-tions may be annular with ~lat surfaces~ as in the pipe Joint of Johnson U. S. Patent No. 3J168,334, or annular with spherical sur~aoes~ as in the flexlble Joint of Herbert et al ~. 8, Patent No. 3~680,895, Laminated ~lexlble elements permit the necessary ~lexural movement of a Joint and also funotion as seals. A Joint ln¢orporating a laminated element has no ~moYing" parts and is not ~ub~ect to the fri¢tionQl ~ear encountered with the ball-and-socket Joints discussed above.
Other flexible pipe ~oints utilizing lamin~ted flexlble elements ar~ described and illustrated in Herbert et al . : -,,: , . ~.
.1 : ,.. ...
~ L~ 4--U. S. Patents Nos. 3,390,899, 3,734,546 and 3,853f337.
While joint3 utilizing laminated flexible elements avoid the wear problem of convention ball-and-socket ~oint~, the laminated elements have a tendency to rupture and fail upon exposure to high axial loads and high pressure different-ial~. In particular, the elastomer layers Or lamlnated elements, while capabl~ of carrying high compres~ive loads, can only with~tand relatively low tension load3. Thus, when two adjacent lengths of pipe are sub~ected to forces that tend to move the lengths axially away from eaoh other, the laminated fle~ible elements are likely to fail. E~forts to 901ve the problem of tension loads have included the u~e o~
tension bars to carry the tension load~ in pre~erence to the laminated flexible elements. Palr~ o~ laminated ~lexible elements may al90 be utilized in a ~oint such that at least one of the ~lexible elements is always loaded in compre9sion, regardless of the relative axial movement between ad~acent lengths o~ pipe. Reducing or eliminating tenæile loads on a laminsted ~lexible element also reduces the llkelihood o~
rupture due to high pressure differentials on the element.
Similarly, bondin~ ad~acent laminations into an integral member lncreaRes the pressure-re3istance of the laminated element.
The present inventlon i9 directed to a flexible ~oint for a fluid condult which provides an improved high-pressure dynamic seal. According to the invention, the ~oint comprises a pair o~ spaced rlgid rings, which are interposed bet~een the ad~acent ends o~ two lengths of conduit. An annular flexible element is diRposed between and sealingly engsges the rings 80 as to define a pair of annular exposed 1~ 4~ ~ 3 0 _5_ side surraccs on the ~lexible element. One o~ the ~ide sur-faces, preferably the radially innermost surface~ is to be exposed to pressurized ~luid ~lowing through the conduit, thereby creating a pressure difrerential across the flexible element between its slde sur~aces. To resist the load that results from the pressure di~rerential, the ~lexible element incorporate~ a body of alastomer that has a thicknes~ between the rlngs which decreases from the one side surrace of the element to the other side surface. Because o~ lts tapering thickness, the body of elastomer i8 dammed or held against rupturing movement in response to the pressure o~ the rluid in the conduit. The flexible element can thus resillently accommodate relative motion between the rings, and hence the lengths of conduit, while providing a fluid-tight~ pressure-resi~tant seal between the rings.
In one embodiment of the invention, the flexibleelement also includes a plurality of spaced apart~ annular shim of a sub~tantially inextensible material embedded in the the body of elastomer. The shims improve the compresslon load carrying capabilltles o~ the elastomer. To insure a ~dammlng~ action on the body of elastomer, the thickne~ses of the shims are not included when the thickness of the body of elastomer i9 determined. The thickness of each shim may be con~tant or tapered. The shims may taper in thickness ~rom the high pressure ~ide sur~ace of the ~lexible element to the lo~ pressure side surface if the spacing between the rigid rings tapers in a corresponding direction and to an extent su~icient to compensate for the tapering shim thicknesses.
If the 3pacing between the rigid rings remains constant~ for example~ the shims may be tapered in thickness from the low 104~Z30 pressure side of the flexible element to -the high pressure side to provide the necessary "damming" effect. In a preferred embodiment, each shim and the body of elastomer are annular in one plane and arcuate in a perpendicular plane or planes. The arcuate configurations of successive shims may be defined by arcs of circles of increasing diameters so that each shim and the body of elastomer is a spherically shaped annulus.
The joint of the present invention is normally incorporated in a pipe joint assembly for flexibly connecting together two lengths of pipe. One such assembly may include a cylindrical housing having an annular body and an annular flange at each end which extends radially inwardly of the housing body.
Each one of a pair of tubular members of smaller diameter than the housing has a flange at one end extending radially outwardly.
The tubular members are received through opposite open ends of the housing so that the flanges of the tubular members are disposed between the flanges of the housing. The other ends of the tubular members project from opposite open ends of the housing. A pair of opposed sealing joints according to the present invention are disposed between opposed flanges. Both joints may be disposed between the flanges of the tubular members or each joint may be disposed between the flange of a different tubular member and the adjacent flange of the housing.
According to one broad aspect, the invention relates to a pipe joint assembly for fluid conduits that receive fluid under a pressure greater than an external ambient pressure on the conduits, said assembly comprising a cylindrical housing including an annular housing body and an annular flange at each end extending radially inwardly of said housing body, and a pair of tubular members of smaller diameter than said housing, each tubular member including a flange at one end extending .
~ -6-radially outwardly of` said member, said f1anges ol` the tut)ulclr members being disposed between the f`langes of the housing and the other ends of the tubular members projecting f`rom opposite ends of the housing for attachment to fluid conduits, the improvement of two annular joints disposed within the housing, each joint comprising: (a) a pair of spaced rigid rings, and (b) an annular flexible element disposed between the rings and sealingly engaging op~(sed surfaces of the rio~C . .
so as to define a pair of annular exposed side suriaces of said flexible element, the flexible element including a body of elastomer which when measured substantially normal to at least one of the opposed surfaces of the rings has a tapered thickness between the rings that decreases from one side surface to the other side surface of the flexible element, the body of elastomer being closely confined in its tapered : configuration along surfaces that extend from the one side surface to the other side surface of the flexible element so as to resist deflection of the elastomer from between the rings in response to pressure exerted on the one side surface of the flexible element, one ring of one joint being in load and motion transmitting engagement with the flange of one tubular member and being sealingly engaged with said one tubular member, one ring of the other joint being in load and motion transmitting engagement with the flange of the other tubular member and being sealingly engaged with said other tubular member, the other ring of each joint being sealing engaged with a fluid-tight portion of the pipe joint assembly such that the two joints together define at least part of a fluid-tight passageway that interconnects the tubular members to permit a flow of fluid between the tubular members, the joints being oriented such that the one side surface of each r -6a-: ' . ' ' '~ , :
, flexible element is exposed to fluid in said passageway and to pressure exerted by fluid in the passageway, the one side surface being the only side surface of each flexible element which is exposed to fluid in sagd passageway, each flexible element resiently accommodating relative motion between the rings that engage the element and providing a fluid-tight seal that is particularly resistant to pressure exerted on the one side surface of the element.
According to another aspect, the invention relates to a pipe joint assembly for a conduit that receives fluid under a pressure greater than an external ambient pressure on the conduit, said assembly comprising a first annular member including a radially extending flange, and a second annular member spaced from and axially aligned with the first annular member, the second annular member including a radially extending flange that is spaced from and disposed in opposed relation to the flange of the first annular member, the improvement of an annular joint disposed between said flanges, said joint being fluid-tight and comprising an annular flexible 20 element having a pair of annular exposed side surfaces and a pair of annular and opposed end surfaces, the flexible element including (a) a body of elastomer which when measured substantially normal to at least one of the end surfaces of the flexible element has a tapered thickness that decreases from one side surface to the other side surface of the element, the b~dy of elastomer being clo-sely confined in its tapered configuration along surfaces that extend from the one side surface to the other side surface of the flexible element so as to resist deflection of the elastomer from between the flanges in response to pressure exerted on the one side surface of the flexible element, and (b) a plurality of spaced annular ~ -6b-,........ . - - .
.. ~ :. . :
- : . :
, " ~,, -- : : . .
- : - . : - ~ : :
.. . . . .
shims of a suhstantially inextensible material eml~edded in the body of elastomer, the thickness of the body of elastomer being exclusive of the thicknesses of the shims, the joint being in load transmitting engagement with the flange of at least one of the first and second annular members and the end surfaces of the flexible element of the joint being sealingly engaged with fluid-tight portions of the pipe joint assembly so that the flexible element defines at least part of a fluid-tight passage-way that interconnects the annular members to permit a flow of fluid between the annular members, the joint being oriented such that the one side surface of the flexible element is exposed to fluid in the passageway and to pressure exerted by fluid in the passageway, the one side surface being the only side surface of the flexible element which is exposed to fluid in the passageway, the flexible element resiliently accommodating relative motion between the annular members and providing a fluid-tight seal that is particularly resistant to pressure exerted on the one side surface of the flexible element.
According to a further aspect, the invention relates to a flexible joint for a conduit that receives fluid under a pressure greater than an external ambient pressure on the conduit, said joint comprising a pair of spaced rigid rings, and an annular flexible element disposed between the rings and sealingly engaging opposed surfaces of the rings so as to define a pair of annular exposed side surfaces of said flexible element, the flexible element including a body of elastomer which when measured substantially normal to at least one of the opposed surfaces of the rings has a tapered thickness between the rings that decreases from the radially innermost one of the side surfaces to the other side surface of the flexible element, ~ -6c-'~
' '' ~040230 the body of elastomer being closely confined in its tapered configuration along surfaces that extend from the one side surface to the other side surface of the flexible element so as to resist deflection of the elastomer from between the rings in response to pressure exerted on the one side surface of the flexible element, the flexible element resiliently accommodating relative motion between the rings that engage the element and providing a fluid-tight seal that is particularly resistant to pressure exerted on the one side surface of the element.
Yet another aspect of the invention relates to a flexible joint for a conduit that receives fluid under a pressure greater than an external ambient pressure on the conduit, said joint being fluid-tight and comprising an annular flexible element having a pair of annular exposed side surfaces and a pair of annular and opposed end surfaces, the flexible element including (a) a body of elastomer which when measured substantially normal to at least one of the end surfaces of the flexible element has a tapered thickness that decreases from the radially innermost one of the side surfaces to the other side surface of the flexible element, and (b) a plurality of spaced annular shims of a substantially inextensible material embedded in the body of elastomer, the thickness of the body of elastomer being exclusive of the thicknesses of the shims, the joint resiliently accommodating relative motion between adjacent sections of conduit and providing, when sealingly engaged with said adjacent conduit :
sections, a fluid-tight seal that is particularly resistant to pressure exerted on the one side surface of the flexible element.
For a better understanding of the invention, reference ;,, ~ ::
-6d-, - ~. . ~ :: .. : . .: :
:- . . : .: : ::
'. ' : ;, ' . . . . .. . ~ , . .
may be made to the following description of an exemplary embodiment, taken in conjunction with the figures of the accompanying drawings, in which:
. . ., . .
. ~ . - , . . .
. ' :
'~ 7-~igure 1 is a diagrammatical view of a drilling barge at an ofrshore location positioned above a wellhead a~sembly on the ocean ~loor;
Figure 2 is a longitudinal view, partly in cross section, o~ one pipe joint assembly illustrated in Figure 1 and incorporating the joint of the present invention;
Figure 3 i9 a fragmentary view, on an enlarged scale, o~ the joint illustrated in Figure 2; and Figure 4 is a view corresponding to ~igure 3 but illustrating an alternate embodiment of the ~oint of the present invention.
Figure 1 of the drawings illustrates a drilling barge 10 floating on the surfaoe 12 of a body of salt water 1~.
Belo~ the barge 10, an underwater wellhead a~sembly 16 i8 positioned on the ocean floor 18. The lower end of a large diameter marine riser pipe 20 is secured to the wellhead assembly 16 by a wellhead connector ?2. Ths upper end of the marine riser pipe 20 is se¢ured to the barge 10 in any conven-tional manner~ 3uoh as by cables 24. The cables 24 position the top of the marine rlser pipe 20 more or less centrally in a drilllng slot 26 that extends throush the barge 10. During drilling operations, a strlng of drilling pipe 32 passes through a rotary table 34 on the drilllng barge 10 and extends throughout the lengt.h o~ the riser pipe 20 into the well.
Although the riser pipe 20 i8 depicted as a continuou9 plpe or tubular member in Flgure 1, the pipe i9 normall~ made up of a multipliclty o~ relatively short tubular seotlons secured together ln any conventional manner. ~ositloned in the riser 20, adJaoent each of its ends, are flexible pipe ~olnt assemblies 28 and 30. Joint assembl~es 28 and 30 ,, ' : :
1~ 4~ 8-accommodate the ma~or lateral movements o~ the riser pipe 20 due to movements of the barge 10, ~or example. Inasmuch as the ~lexible pipe ~oint assemblies 28 and 30 are essentially identical in construction, they will be described in detail with re~erence only to the joint 30, a~ ~hown in Figure 2.
The pipe joint assembly 30 has a cylindrical outer housing 36 that compri~es an open-ended tubular or annular body 38 and a pair of annular flange members 40a and 40b.
The flange members 40a and 40b are positioned at opposite ends of the body 38 and are releasably secured to the body by lug bolts 42, ~or example. When mounted on the body 38, the ~lange members 40a and 40b extend radially inwardly from the body.
Ad~acent the flange 40a o~ the hou~ing 36 19 a tubular member 44a that extends through the central opening in the rlange 40a. A flange 46a is ~ormed at the end o~ the tubular member 44a which i8 inside the housing 36. The ~lange 46a extends radially outwardly of the tubular member 44a and over-laps the M ange 40a of the housing 36. The overlapping or inter~ering relationship of the flanges 40a and 46a requires the flange 40a to be separable from the body 38 of the housing 36 to permit assembly o~ the tubular member 44a within the housing. An identical tubular member 44b that has a ~lange 46b is dlsposed ad~acent the other end o~ the housing 36 in a corresponding overlapping relationship with the flange 40b.
Annular replaceable wear bushing 43a~ 43b, 45a, 45b, 47a and 47b oover the interior circum~erence o~ each Or the tubular members 44. The bushings 43~ 45 and 47 protect the tubular members 44 against the abrasive action o~ well tools passing through the Joint assembly 30 and drilling mud flowing through the assembly outside the drilling pipe 32.
1(14()Z30 _9_ Between the ~langes 40a and 46a and bGtween the ~langes 40b ~nd 46b are annular laminated bearings 48a and 48b, respectively. Each of the bearings 48 includes two relatively massive, annular end plates 50 and 52 and an intermediate flexible element 54. The end plates 50 and 52 are received on appropriately con~igured sur~aces of the flange~ 40 and 46, respectively. The interfaces between the plates 50 and 52 and the flanges 40 and 46 are not sealed. The ~lexible element 54 is bonded to the end plates 50 and 52 and incorporate~ a plurality of alternating layers of elastomeric material and a material that is substantially inextensible or nonextensible compared to the elastomeric material. The inextensible layers are preferably ~ormed o~ steel, while the elastomeric layers are preferably formed of natural rubber. Other inexten~ible and elastomeric materials may be substituted for the steel and rubber where appropriate. Alternate elastomeria materials include synthetic rubber, while alternate inextensible mater-ials include other metals, ~iberglass, and reinforced plastics.
The layers o~ eaah flexible element 54 and the adjaoent sur-faces o~ the assoaiated end plates 50 and 52 have circular conrigurations in longitudinal section. The over-all spherical shapes o~ the bearlngs 48a and b permit the bearings to ~unction QS universal ~oints with the relative motion be-t~reen ad~acent relatively rigid components (i.e., the in-extensible layers and the end plates) being accommodated by ~lexing or shearlng o~ the elastomer layers.
Interposed between the flanges 46a and 46b o~ the tubular members 44 are a pair o~ flexible ~oints ~;6a and b.
Eaah of the ~oints 56a and b includes two relatively massive, rigid rings 58 and 60 and an annular flexible element 62 -.
~S~40230 located between the ring~. The ~lexible element 62, which includes elastomer, ls relatively so~t or more flexible compared to the flexible elements 54 of the bearings 48. ~he difference in ~lexibility or stirfness may be achieved b~
utilizing a "sorter" elastomer or by constructing the flexible element 62 to have a lower shape factor than the flegible elements 54, for example. The element 62 is bonded to each o~ the rings 58 and 60 so as to define on the ~lexible element a pair of annular side surraces 64 and 66 which are exposed or ~ree. As in the bearings 48a and b, the ~lexible elements 62a and b and the ad~acent surfaces of the end rings 58a and b have circular shapes in longitudinal section. The ~oints 56a and b may thus functlon as universal joints, like the bearing~ 48a and b.
The end rings 58a and b Or the ~oints 56a and b are carrled on and engage sur~aces o~ the flanges 46a and b appro-priately configured to prevent radial shi~ting Or the rings.
Grooves 63a and b formed in the ad~acent surfaces of the flanges 46a and b reoeive resilient 0-rings 65a and b (See also Figure 3) to seal the interfaces between the ~langes and the rlngs 58. End rings 60a and 60b engage each other and rit together. Axially extendlng, annular flanges 68a and 68b on the rings 60a and b overlap in an axial direction to prevent relative radial move~ent between the rings. As best sho~n in Figure 3, grooves 67a and 67b are ~ormed in the rings 60a and b to accept resilient 0-rings 69a and b, which seal the inter-~ace between the rings 60. None o~ the rings 58a, 58b, 60a or 60b is secured to the ad~acent metal sur~ace that the ring contacts. The seallng action o~ the 0-rings 65a and b and the 0-ring 69b is insured by constantly maintainlng a : -. ., . :
1~)4(~Z30 -11-compression load on the Joints 56a and 56b, as will be described herein.
When the various components of the joint assembly 30 are assembled as shown in Figure 2, the exposed end~ of the tubular members 44a and 44b are connected to the ends o~
ad~acent lengths of riser pipe (not shown). The riser pipe 20, throughout its length, is normally malntained in tension.
This tension load, which is transmitted to the joint assembly 30, is carried by compression loading of the laminated elasto-meric bearings 48a and 48b. The load is applied through theflanges 46a and b and is transmitted to the housing 36. Since a compression load on the bearings 48a and b wlll result in de~lection o~ the elastomer in the bearings, the flanges 46a and b of the tubular member~ 44a and b wlll tend to move away from each other and away from the ~olnts 56a and b. To prevent such movement ~rom interrupting the seals at the inter~aces between ~langes 46 and rings 58 and between rings 60a and 60b, the internal oomponents of ~oint assembly 30 are prede~leoted and thus preloaded~ on assembly, between the housing ~langes 40a and 40b. The assembly prede~lection or preload derlects the Joints 56a and b in preferen¢e to the bearings 48a and b due to the di~erence in the sti~nesses of the ~lexible elements 54 and 62, Thus, when the tension load on the riser pipe 20 is transmitted to the tubular members 44a and 44b and the bearings 48a and 48b, the resulting de~lection of the bearings i8 not su~ficient to relieve completely the compres~ion load on the ~oints 56a and 56b. Consequently, the 0-rings 65a, 65b and 69b are always loaded in compre99ion to seal the lnter~aces between ~langes 46 and rings 58 and between ring 60a and ring 60b The preload also pro~ides - :
.
~ Z3~ -~2~
limited frictional engagement between adjacent metal surfaces to prevent relative rotation between the flanges 46 and the rings 58, for example.
The spherical configurations Or the joints 56a and 56b, together with the ~pherical configurations of the bearings 48a and 48b, permit angular misalignment~ between the lengths of riser pipe 20 on either side of the joint assembly 30.
Angled relative orientations of the lengths of riser pipe 20 are accommodated by shearing of the elastomer in the elements 54a, 54b, 62a and 62b, as indicated above. The elastomer in the ~lexible elements 54a, 54b, 62a and 62b will also shear to accommodate rotational movements of the riser pipe sections about their longitudinal axes, During their de~lections~ the ~lexible element3 62 maintain a rluid-tight ~eal against the highly pressurized and abrasive drilling mud, ~or example, that ~lows through the riser pipe 20 along the outside Or the drilling pipe 32. (As noted above, the bearing~ 48 need not provlde a fluid-tight seal against the sea water surrounding the ~oint assembly 30.) The sealing action Or the ~oints 56a and 56b is facilitated by thelr unique design, as discussed ln detail below with parti¢ular reference to ~oint 56b.
A9 disoussed above and illustrated in Figure 2, the radially inner side surfaoes 64 of the flexible elements 62 Or ~oints 56 are normally exposed to a highly pressurized ~luid, such as drilllng mud. The drilling mud is at a pre~-sure substantially higher than the pressure o~ the fluid, such as sea water, to which the opposite side ~urfaces 66 of the flexible elements 62 are exposed. The pressure di~ferential across the elements 62 tends to ~orce the elements radially outwardly from between the rigid rings 58 and 60. To 1~4(J~ 30 -i3-counteract the ef~ects of the pressure differential~ the flexible elements 62 comprise outwardly tapered bodies of elastomer 70. As best shown in Figure 3 with regard to joint 56b, the body o~ elastomer 70b has a thickness (measured 5 substantially normal to the curved surfaces of rings 58b and 60b) which decrease3 from the high pressure side surface 64b of the flexible element 62b to the low pressure side surface 66b of the element. The tapering thickness of the body of elastomer 70b, which has been exaggerated for purpose~ of lO illustration in Figure 3~ is achieved b~ tapering the spacing between the ad~acent arcuate surfaces of the rigid rings 58b and 60b. The taper effectively results in the elastomer being 'tdammed" or retained between the two rings 58b and 60b against radially outward and upward rupturing movement. This positive 15 mechanical interlock provides a more effective high pressure ~eal than is ~ound in similar flexible ~oint~ that rely solely on the strength of the bond between the body Or elastomer and the ad~acent metal part9.
To increase the capacity of the joint 56b of Figure 3 20 to Y ithstand pressure differentials across the body of elasto-mer 70b and/or to reduce the stress in the elastomer for a given pressure differential~ metal shims 72 are embedded in the elastomer 70b at spaced apart locstions between the rings 58b and 60b. The shims 72, which are substantially inexten-25 sible compared to the elastomer 70b, are continuous annularmembers and have arcuate con~igurations in longitudinal section. The arcuate lines of the shims 72 are pre~erably circular arcs. Such a configuration best accommodates the ball-and-socket type operation of the ~oint 56b and ls more 30 convenient to manu~acture than other curved shapes. The arcs may be taken from a single circle Or ~ixed diamete~, or from different diameter circles such that the diameters of successive shims increase ~rith increasing radial distance of the particular shim from the nominal center of the joint. The 5 spacing between the individual shims 72 and between the endmost shims and the adjacent surf`aces of the rings 58b and 60b decreases from the high pressure side 64b of the flexible element 62b to the low pr essure side 66b. With shims defined by circular arcs, the tapering in the spacing is achieved by 10 axially displacing the center of the circle that defines the arcuate shape of each shim ~rom the center of the circle de-flning the arcuate configuration of the adJacent~ radially inwardly locatad shim, While the damming effect in joint 56b i8 provided by a decrease in the spacing between the end rings 15 58b and 60b, the tapering of the thickness of the elastomer body 70b may be accomplished through other techniques. For example, the thicknesses of the shims 72 r~y be tapered from the low pressure side 66b of the flexible element 62b to the high pressure side 64b without tapering the spacing between 20 the end rings 58b and 60b.
It should be noted that the use of tapered layers of elastomer in a laminated elastomeric bearing is kno~m in the art~ as illustrated by Figure 3 of Krotz U~ S. Patent No.
One type of flexible ~oint used in ri~er pipes consists of a ball member having a precisely machined spherical surface and a socket member ha~ing a complementary, precisely machined 3pherical surface. The ~oint is flexed by sliding one o~ the spherical surfaces relative to the other. Resilient O-rings help ~eal the Joint at the interface between the slid-ing sur~aces. The flexural movement of such a ball joint i9 impaired, however, when the Joint is ~ub~ected to high pres-sures. The ~oint is al90 subJect to ~rictional wear and deterioration o~ both the slidine surfaces and the O-ring seals, which requires frequent repair or replacement of the ~oint.
Another type of flexible joint for fluid conduit~, such as marine riser pipes, utilizes annular flexible ele-ments disposea between flanges secured to adJaoent ends of different ~ections of condu~t. The ~lexible elements ¢omprise alternating layers of a rigid and a resilient material, uhich are normally metal and an elastomer. The layers or lamina-tions may be annular with ~lat surfaces~ as in the pipe Joint of Johnson U. S. Patent No. 3J168,334, or annular with spherical sur~aoes~ as in the flexlble Joint of Herbert et al ~. 8, Patent No. 3~680,895, Laminated ~lexlble elements permit the necessary ~lexural movement of a Joint and also funotion as seals. A Joint ln¢orporating a laminated element has no ~moYing" parts and is not ~ub~ect to the fri¢tionQl ~ear encountered with the ball-and-socket Joints discussed above.
Other flexible pipe ~oints utilizing lamin~ted flexlble elements ar~ described and illustrated in Herbert et al . : -,,: , . ~.
.1 : ,.. ...
~ L~ 4--U. S. Patents Nos. 3,390,899, 3,734,546 and 3,853f337.
While joint3 utilizing laminated flexible elements avoid the wear problem of convention ball-and-socket ~oint~, the laminated elements have a tendency to rupture and fail upon exposure to high axial loads and high pressure different-ial~. In particular, the elastomer layers Or lamlnated elements, while capabl~ of carrying high compres~ive loads, can only with~tand relatively low tension load3. Thus, when two adjacent lengths of pipe are sub~ected to forces that tend to move the lengths axially away from eaoh other, the laminated fle~ible elements are likely to fail. E~forts to 901ve the problem of tension loads have included the u~e o~
tension bars to carry the tension load~ in pre~erence to the laminated flexible elements. Palr~ o~ laminated ~lexible elements may al90 be utilized in a ~oint such that at least one of the ~lexible elements is always loaded in compre9sion, regardless of the relative axial movement between ad~acent lengths o~ pipe. Reducing or eliminating tenæile loads on a laminsted ~lexible element also reduces the llkelihood o~
rupture due to high pressure differentials on the element.
Similarly, bondin~ ad~acent laminations into an integral member lncreaRes the pressure-re3istance of the laminated element.
The present inventlon i9 directed to a flexible ~oint for a fluid condult which provides an improved high-pressure dynamic seal. According to the invention, the ~oint comprises a pair o~ spaced rlgid rings, which are interposed bet~een the ad~acent ends o~ two lengths of conduit. An annular flexible element is diRposed between and sealingly engsges the rings 80 as to define a pair of annular exposed 1~ 4~ ~ 3 0 _5_ side surraccs on the ~lexible element. One o~ the ~ide sur-faces, preferably the radially innermost surface~ is to be exposed to pressurized ~luid ~lowing through the conduit, thereby creating a pressure difrerential across the flexible element between its slde sur~aces. To resist the load that results from the pressure di~rerential, the ~lexible element incorporate~ a body of alastomer that has a thicknes~ between the rlngs which decreases from the one side surrace of the element to the other side surface. Because o~ lts tapering thickness, the body of elastomer i8 dammed or held against rupturing movement in response to the pressure o~ the rluid in the conduit. The flexible element can thus resillently accommodate relative motion between the rings, and hence the lengths of conduit, while providing a fluid-tight~ pressure-resi~tant seal between the rings.
In one embodiment of the invention, the flexibleelement also includes a plurality of spaced apart~ annular shim of a sub~tantially inextensible material embedded in the the body of elastomer. The shims improve the compresslon load carrying capabilltles o~ the elastomer. To insure a ~dammlng~ action on the body of elastomer, the thickne~ses of the shims are not included when the thickness of the body of elastomer i9 determined. The thickness of each shim may be con~tant or tapered. The shims may taper in thickness ~rom the high pressure ~ide sur~ace of the ~lexible element to the lo~ pressure side surface if the spacing between the rigid rings tapers in a corresponding direction and to an extent su~icient to compensate for the tapering shim thicknesses.
If the 3pacing between the rigid rings remains constant~ for example~ the shims may be tapered in thickness from the low 104~Z30 pressure side of the flexible element to -the high pressure side to provide the necessary "damming" effect. In a preferred embodiment, each shim and the body of elastomer are annular in one plane and arcuate in a perpendicular plane or planes. The arcuate configurations of successive shims may be defined by arcs of circles of increasing diameters so that each shim and the body of elastomer is a spherically shaped annulus.
The joint of the present invention is normally incorporated in a pipe joint assembly for flexibly connecting together two lengths of pipe. One such assembly may include a cylindrical housing having an annular body and an annular flange at each end which extends radially inwardly of the housing body.
Each one of a pair of tubular members of smaller diameter than the housing has a flange at one end extending radially outwardly.
The tubular members are received through opposite open ends of the housing so that the flanges of the tubular members are disposed between the flanges of the housing. The other ends of the tubular members project from opposite open ends of the housing. A pair of opposed sealing joints according to the present invention are disposed between opposed flanges. Both joints may be disposed between the flanges of the tubular members or each joint may be disposed between the flange of a different tubular member and the adjacent flange of the housing.
According to one broad aspect, the invention relates to a pipe joint assembly for fluid conduits that receive fluid under a pressure greater than an external ambient pressure on the conduits, said assembly comprising a cylindrical housing including an annular housing body and an annular flange at each end extending radially inwardly of said housing body, and a pair of tubular members of smaller diameter than said housing, each tubular member including a flange at one end extending .
~ -6-radially outwardly of` said member, said f1anges ol` the tut)ulclr members being disposed between the f`langes of the housing and the other ends of the tubular members projecting f`rom opposite ends of the housing for attachment to fluid conduits, the improvement of two annular joints disposed within the housing, each joint comprising: (a) a pair of spaced rigid rings, and (b) an annular flexible element disposed between the rings and sealingly engaging op~(sed surfaces of the rio~C . .
so as to define a pair of annular exposed side suriaces of said flexible element, the flexible element including a body of elastomer which when measured substantially normal to at least one of the opposed surfaces of the rings has a tapered thickness between the rings that decreases from one side surface to the other side surface of the flexible element, the body of elastomer being closely confined in its tapered : configuration along surfaces that extend from the one side surface to the other side surface of the flexible element so as to resist deflection of the elastomer from between the rings in response to pressure exerted on the one side surface of the flexible element, one ring of one joint being in load and motion transmitting engagement with the flange of one tubular member and being sealingly engaged with said one tubular member, one ring of the other joint being in load and motion transmitting engagement with the flange of the other tubular member and being sealingly engaged with said other tubular member, the other ring of each joint being sealing engaged with a fluid-tight portion of the pipe joint assembly such that the two joints together define at least part of a fluid-tight passageway that interconnects the tubular members to permit a flow of fluid between the tubular members, the joints being oriented such that the one side surface of each r -6a-: ' . ' ' '~ , :
, flexible element is exposed to fluid in said passageway and to pressure exerted by fluid in the passageway, the one side surface being the only side surface of each flexible element which is exposed to fluid in sagd passageway, each flexible element resiently accommodating relative motion between the rings that engage the element and providing a fluid-tight seal that is particularly resistant to pressure exerted on the one side surface of the element.
According to another aspect, the invention relates to a pipe joint assembly for a conduit that receives fluid under a pressure greater than an external ambient pressure on the conduit, said assembly comprising a first annular member including a radially extending flange, and a second annular member spaced from and axially aligned with the first annular member, the second annular member including a radially extending flange that is spaced from and disposed in opposed relation to the flange of the first annular member, the improvement of an annular joint disposed between said flanges, said joint being fluid-tight and comprising an annular flexible 20 element having a pair of annular exposed side surfaces and a pair of annular and opposed end surfaces, the flexible element including (a) a body of elastomer which when measured substantially normal to at least one of the end surfaces of the flexible element has a tapered thickness that decreases from one side surface to the other side surface of the element, the b~dy of elastomer being clo-sely confined in its tapered configuration along surfaces that extend from the one side surface to the other side surface of the flexible element so as to resist deflection of the elastomer from between the flanges in response to pressure exerted on the one side surface of the flexible element, and (b) a plurality of spaced annular ~ -6b-,........ . - - .
.. ~ :. . :
- : . :
, " ~,, -- : : . .
- : - . : - ~ : :
.. . . . .
shims of a suhstantially inextensible material eml~edded in the body of elastomer, the thickness of the body of elastomer being exclusive of the thicknesses of the shims, the joint being in load transmitting engagement with the flange of at least one of the first and second annular members and the end surfaces of the flexible element of the joint being sealingly engaged with fluid-tight portions of the pipe joint assembly so that the flexible element defines at least part of a fluid-tight passage-way that interconnects the annular members to permit a flow of fluid between the annular members, the joint being oriented such that the one side surface of the flexible element is exposed to fluid in the passageway and to pressure exerted by fluid in the passageway, the one side surface being the only side surface of the flexible element which is exposed to fluid in the passageway, the flexible element resiliently accommodating relative motion between the annular members and providing a fluid-tight seal that is particularly resistant to pressure exerted on the one side surface of the flexible element.
According to a further aspect, the invention relates to a flexible joint for a conduit that receives fluid under a pressure greater than an external ambient pressure on the conduit, said joint comprising a pair of spaced rigid rings, and an annular flexible element disposed between the rings and sealingly engaging opposed surfaces of the rings so as to define a pair of annular exposed side surfaces of said flexible element, the flexible element including a body of elastomer which when measured substantially normal to at least one of the opposed surfaces of the rings has a tapered thickness between the rings that decreases from the radially innermost one of the side surfaces to the other side surface of the flexible element, ~ -6c-'~
' '' ~040230 the body of elastomer being closely confined in its tapered configuration along surfaces that extend from the one side surface to the other side surface of the flexible element so as to resist deflection of the elastomer from between the rings in response to pressure exerted on the one side surface of the flexible element, the flexible element resiliently accommodating relative motion between the rings that engage the element and providing a fluid-tight seal that is particularly resistant to pressure exerted on the one side surface of the element.
Yet another aspect of the invention relates to a flexible joint for a conduit that receives fluid under a pressure greater than an external ambient pressure on the conduit, said joint being fluid-tight and comprising an annular flexible element having a pair of annular exposed side surfaces and a pair of annular and opposed end surfaces, the flexible element including (a) a body of elastomer which when measured substantially normal to at least one of the end surfaces of the flexible element has a tapered thickness that decreases from the radially innermost one of the side surfaces to the other side surface of the flexible element, and (b) a plurality of spaced annular shims of a substantially inextensible material embedded in the body of elastomer, the thickness of the body of elastomer being exclusive of the thicknesses of the shims, the joint resiliently accommodating relative motion between adjacent sections of conduit and providing, when sealingly engaged with said adjacent conduit :
sections, a fluid-tight seal that is particularly resistant to pressure exerted on the one side surface of the flexible element.
For a better understanding of the invention, reference ;,, ~ ::
-6d-, - ~. . ~ :: .. : . .: :
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may be made to the following description of an exemplary embodiment, taken in conjunction with the figures of the accompanying drawings, in which:
. . ., . .
. ~ . - , . . .
. ' :
'~ 7-~igure 1 is a diagrammatical view of a drilling barge at an ofrshore location positioned above a wellhead a~sembly on the ocean ~loor;
Figure 2 is a longitudinal view, partly in cross section, o~ one pipe joint assembly illustrated in Figure 1 and incorporating the joint of the present invention;
Figure 3 i9 a fragmentary view, on an enlarged scale, o~ the joint illustrated in Figure 2; and Figure 4 is a view corresponding to ~igure 3 but illustrating an alternate embodiment of the ~oint of the present invention.
Figure 1 of the drawings illustrates a drilling barge 10 floating on the surfaoe 12 of a body of salt water 1~.
Belo~ the barge 10, an underwater wellhead a~sembly 16 i8 positioned on the ocean floor 18. The lower end of a large diameter marine riser pipe 20 is secured to the wellhead assembly 16 by a wellhead connector ?2. Ths upper end of the marine riser pipe 20 is se¢ured to the barge 10 in any conven-tional manner~ 3uoh as by cables 24. The cables 24 position the top of the marine rlser pipe 20 more or less centrally in a drilllng slot 26 that extends throush the barge 10. During drilling operations, a strlng of drilling pipe 32 passes through a rotary table 34 on the drilllng barge 10 and extends throughout the lengt.h o~ the riser pipe 20 into the well.
Although the riser pipe 20 i8 depicted as a continuou9 plpe or tubular member in Flgure 1, the pipe i9 normall~ made up of a multipliclty o~ relatively short tubular seotlons secured together ln any conventional manner. ~ositloned in the riser 20, adJaoent each of its ends, are flexible pipe ~olnt assemblies 28 and 30. Joint assembl~es 28 and 30 ,, ' : :
1~ 4~ 8-accommodate the ma~or lateral movements o~ the riser pipe 20 due to movements of the barge 10, ~or example. Inasmuch as the ~lexible pipe ~oint assemblies 28 and 30 are essentially identical in construction, they will be described in detail with re~erence only to the joint 30, a~ ~hown in Figure 2.
The pipe joint assembly 30 has a cylindrical outer housing 36 that compri~es an open-ended tubular or annular body 38 and a pair of annular flange members 40a and 40b.
The flange members 40a and 40b are positioned at opposite ends of the body 38 and are releasably secured to the body by lug bolts 42, ~or example. When mounted on the body 38, the ~lange members 40a and 40b extend radially inwardly from the body.
Ad~acent the flange 40a o~ the hou~ing 36 19 a tubular member 44a that extends through the central opening in the rlange 40a. A flange 46a is ~ormed at the end o~ the tubular member 44a which i8 inside the housing 36. The ~lange 46a extends radially outwardly of the tubular member 44a and over-laps the M ange 40a of the housing 36. The overlapping or inter~ering relationship of the flanges 40a and 46a requires the flange 40a to be separable from the body 38 of the housing 36 to permit assembly o~ the tubular member 44a within the housing. An identical tubular member 44b that has a ~lange 46b is dlsposed ad~acent the other end o~ the housing 36 in a corresponding overlapping relationship with the flange 40b.
Annular replaceable wear bushing 43a~ 43b, 45a, 45b, 47a and 47b oover the interior circum~erence o~ each Or the tubular members 44. The bushings 43~ 45 and 47 protect the tubular members 44 against the abrasive action o~ well tools passing through the Joint assembly 30 and drilling mud flowing through the assembly outside the drilling pipe 32.
1(14()Z30 _9_ Between the ~langes 40a and 46a and bGtween the ~langes 40b ~nd 46b are annular laminated bearings 48a and 48b, respectively. Each of the bearings 48 includes two relatively massive, annular end plates 50 and 52 and an intermediate flexible element 54. The end plates 50 and 52 are received on appropriately con~igured sur~aces of the flange~ 40 and 46, respectively. The interfaces between the plates 50 and 52 and the flanges 40 and 46 are not sealed. The ~lexible element 54 is bonded to the end plates 50 and 52 and incorporate~ a plurality of alternating layers of elastomeric material and a material that is substantially inextensible or nonextensible compared to the elastomeric material. The inextensible layers are preferably ~ormed o~ steel, while the elastomeric layers are preferably formed of natural rubber. Other inexten~ible and elastomeric materials may be substituted for the steel and rubber where appropriate. Alternate elastomeria materials include synthetic rubber, while alternate inextensible mater-ials include other metals, ~iberglass, and reinforced plastics.
The layers o~ eaah flexible element 54 and the adjaoent sur-faces o~ the assoaiated end plates 50 and 52 have circular conrigurations in longitudinal section. The over-all spherical shapes o~ the bearlngs 48a and b permit the bearings to ~unction QS universal ~oints with the relative motion be-t~reen ad~acent relatively rigid components (i.e., the in-extensible layers and the end plates) being accommodated by ~lexing or shearlng o~ the elastomer layers.
Interposed between the flanges 46a and 46b o~ the tubular members 44 are a pair o~ flexible ~oints ~;6a and b.
Eaah of the ~oints 56a and b includes two relatively massive, rigid rings 58 and 60 and an annular flexible element 62 -.
~S~40230 located between the ring~. The ~lexible element 62, which includes elastomer, ls relatively so~t or more flexible compared to the flexible elements 54 of the bearings 48. ~he difference in ~lexibility or stirfness may be achieved b~
utilizing a "sorter" elastomer or by constructing the flexible element 62 to have a lower shape factor than the flegible elements 54, for example. The element 62 is bonded to each o~ the rings 58 and 60 so as to define on the ~lexible element a pair of annular side surraces 64 and 66 which are exposed or ~ree. As in the bearings 48a and b, the ~lexible elements 62a and b and the ad~acent surfaces of the end rings 58a and b have circular shapes in longitudinal section. The ~oints 56a and b may thus functlon as universal joints, like the bearing~ 48a and b.
The end rings 58a and b Or the ~oints 56a and b are carrled on and engage sur~aces o~ the flanges 46a and b appro-priately configured to prevent radial shi~ting Or the rings.
Grooves 63a and b formed in the ad~acent surfaces of the flanges 46a and b reoeive resilient 0-rings 65a and b (See also Figure 3) to seal the interfaces between the ~langes and the rlngs 58. End rings 60a and 60b engage each other and rit together. Axially extendlng, annular flanges 68a and 68b on the rings 60a and b overlap in an axial direction to prevent relative radial move~ent between the rings. As best sho~n in Figure 3, grooves 67a and 67b are ~ormed in the rings 60a and b to accept resilient 0-rings 69a and b, which seal the inter-~ace between the rings 60. None o~ the rings 58a, 58b, 60a or 60b is secured to the ad~acent metal sur~ace that the ring contacts. The seallng action o~ the 0-rings 65a and b and the 0-ring 69b is insured by constantly maintainlng a : -. ., . :
1~)4(~Z30 -11-compression load on the Joints 56a and 56b, as will be described herein.
When the various components of the joint assembly 30 are assembled as shown in Figure 2, the exposed end~ of the tubular members 44a and 44b are connected to the ends o~
ad~acent lengths of riser pipe (not shown). The riser pipe 20, throughout its length, is normally malntained in tension.
This tension load, which is transmitted to the joint assembly 30, is carried by compression loading of the laminated elasto-meric bearings 48a and 48b. The load is applied through theflanges 46a and b and is transmitted to the housing 36. Since a compression load on the bearings 48a and b wlll result in de~lection o~ the elastomer in the bearings, the flanges 46a and b of the tubular member~ 44a and b wlll tend to move away from each other and away from the ~olnts 56a and b. To prevent such movement ~rom interrupting the seals at the inter~aces between ~langes 46 and rings 58 and between rings 60a and 60b, the internal oomponents of ~oint assembly 30 are prede~leoted and thus preloaded~ on assembly, between the housing ~langes 40a and 40b. The assembly prede~lection or preload derlects the Joints 56a and b in preferen¢e to the bearings 48a and b due to the di~erence in the sti~nesses of the ~lexible elements 54 and 62, Thus, when the tension load on the riser pipe 20 is transmitted to the tubular members 44a and 44b and the bearings 48a and 48b, the resulting de~lection of the bearings i8 not su~ficient to relieve completely the compres~ion load on the ~oints 56a and 56b. Consequently, the 0-rings 65a, 65b and 69b are always loaded in compre99ion to seal the lnter~aces between ~langes 46 and rings 58 and between ring 60a and ring 60b The preload also pro~ides - :
.
~ Z3~ -~2~
limited frictional engagement between adjacent metal surfaces to prevent relative rotation between the flanges 46 and the rings 58, for example.
The spherical configurations Or the joints 56a and 56b, together with the ~pherical configurations of the bearings 48a and 48b, permit angular misalignment~ between the lengths of riser pipe 20 on either side of the joint assembly 30.
Angled relative orientations of the lengths of riser pipe 20 are accommodated by shearing of the elastomer in the elements 54a, 54b, 62a and 62b, as indicated above. The elastomer in the ~lexible elements 54a, 54b, 62a and 62b will also shear to accommodate rotational movements of the riser pipe sections about their longitudinal axes, During their de~lections~ the ~lexible element3 62 maintain a rluid-tight ~eal against the highly pressurized and abrasive drilling mud, ~or example, that ~lows through the riser pipe 20 along the outside Or the drilling pipe 32. (As noted above, the bearing~ 48 need not provlde a fluid-tight seal against the sea water surrounding the ~oint assembly 30.) The sealing action Or the ~oints 56a and 56b is facilitated by thelr unique design, as discussed ln detail below with parti¢ular reference to ~oint 56b.
A9 disoussed above and illustrated in Figure 2, the radially inner side surfaoes 64 of the flexible elements 62 Or ~oints 56 are normally exposed to a highly pressurized ~luid, such as drilllng mud. The drilling mud is at a pre~-sure substantially higher than the pressure o~ the fluid, such as sea water, to which the opposite side ~urfaces 66 of the flexible elements 62 are exposed. The pressure di~ferential across the elements 62 tends to ~orce the elements radially outwardly from between the rigid rings 58 and 60. To 1~4(J~ 30 -i3-counteract the ef~ects of the pressure differential~ the flexible elements 62 comprise outwardly tapered bodies of elastomer 70. As best shown in Figure 3 with regard to joint 56b, the body o~ elastomer 70b has a thickness (measured 5 substantially normal to the curved surfaces of rings 58b and 60b) which decrease3 from the high pressure side surface 64b of the flexible element 62b to the low pressure side surface 66b of the element. The tapering thickness of the body of elastomer 70b, which has been exaggerated for purpose~ of lO illustration in Figure 3~ is achieved b~ tapering the spacing between the ad~acent arcuate surfaces of the rigid rings 58b and 60b. The taper effectively results in the elastomer being 'tdammed" or retained between the two rings 58b and 60b against radially outward and upward rupturing movement. This positive 15 mechanical interlock provides a more effective high pressure ~eal than is ~ound in similar flexible ~oint~ that rely solely on the strength of the bond between the body Or elastomer and the ad~acent metal part9.
To increase the capacity of the joint 56b of Figure 3 20 to Y ithstand pressure differentials across the body of elasto-mer 70b and/or to reduce the stress in the elastomer for a given pressure differential~ metal shims 72 are embedded in the elastomer 70b at spaced apart locstions between the rings 58b and 60b. The shims 72, which are substantially inexten-25 sible compared to the elastomer 70b, are continuous annularmembers and have arcuate con~igurations in longitudinal section. The arcuate lines of the shims 72 are pre~erably circular arcs. Such a configuration best accommodates the ball-and-socket type operation of the ~oint 56b and ls more 30 convenient to manu~acture than other curved shapes. The arcs may be taken from a single circle Or ~ixed diamete~, or from different diameter circles such that the diameters of successive shims increase ~rith increasing radial distance of the particular shim from the nominal center of the joint. The 5 spacing between the individual shims 72 and between the endmost shims and the adjacent surf`aces of the rings 58b and 60b decreases from the high pressure side 64b of the flexible element 62b to the low pr essure side 66b. With shims defined by circular arcs, the tapering in the spacing is achieved by 10 axially displacing the center of the circle that defines the arcuate shape of each shim ~rom the center of the circle de-flning the arcuate configuration of the adJacent~ radially inwardly locatad shim, While the damming effect in joint 56b i8 provided by a decrease in the spacing between the end rings 15 58b and 60b, the tapering of the thickness of the elastomer body 70b may be accomplished through other techniques. For example, the thicknesses of the shims 72 r~y be tapered from the low pressure side 66b of the flexible element 62b to the high pressure side 64b without tapering the spacing between 20 the end rings 58b and 60b.
It should be noted that the use of tapered layers of elastomer in a laminated elastomeric bearing is kno~m in the art~ as illustrated by Figure 3 of Krotz U~ S. Patent No.
3~179,400 and by Figure 7 of Hinl{s U. S. Patent No. 3~071,422.
25 Neither patent, however, recognizes the construotion and use o~ such an elastomeric bearing as a sealing pipe ~oint.
Figure 4 o~ the application illustrates an alternate embodiment of the ~oints 56. In the embodiment of Figure 4 not only does the thickness of the body of elastomer 70bt 30 diminish from the high pressure side ~urface 64bt of the -, . :~' ,, - - ., ~ .
~ 15-flexible element 62b' to the low pressure surface 66b', but the shims 72t similarly taper from the high pressure side to the low pressure side of the fleYible element 62bt, The tapering Or the sims 72l permits a reduction in the amount of metal used in the flexible element 62bt, as compared to the element 62b of Figure 3. The basis for tapering the shims may best be understood by considering that the annular shims 72' are everwhere subjected to radiall~ directed forces which place each shim 72' in what may be termed Ithoop tension". The "hoop tension" i8 greatest at the edges of the shims 72' adjacent the high pre~sure side 64bl of the flexible element 62bl. The tension diminishes with increasing distance from the longitudinal axis of the pipe joint assembly 30. Thus, the ends of the shims 72' which are uppermost in Figure 4 are 15 subject to a lesser "hoop tension" than the lower ends of the shims. The smaller tlhoop tension" requires a smaller thick-ness of metal to resist the tension load and the shims may be tapered accordingly.
It will be understood that the embodiment desoribed above is merely exemplary and that persons skilled in the art may make many variations and modifications without departing from the splrit and scope of the invention. For example, indivldual rings 58 and 60 may be fabricated in one piece with ad~acent metal oomponents such as flanges 46. The ~oints 56 may also be utilized as combined bearings and seals in a variety of dif~erent pipe ~oint assemblies~ suoh as those shown in the var~ous Figures of Herbert etal U. S. Patent No. 3,6Bo,8g5. ~11 such modifications and variations are intended to be within the scope of the invention as defined in the appended claim~.
.
25 Neither patent, however, recognizes the construotion and use o~ such an elastomeric bearing as a sealing pipe ~oint.
Figure 4 o~ the application illustrates an alternate embodiment of the ~oints 56. In the embodiment of Figure 4 not only does the thickness of the body of elastomer 70bt 30 diminish from the high pressure side ~urface 64bt of the -, . :~' ,, - - ., ~ .
~ 15-flexible element 62b' to the low pressure surface 66b', but the shims 72t similarly taper from the high pressure side to the low pressure side of the fleYible element 62bt, The tapering Or the sims 72l permits a reduction in the amount of metal used in the flexible element 62bt, as compared to the element 62b of Figure 3. The basis for tapering the shims may best be understood by considering that the annular shims 72' are everwhere subjected to radiall~ directed forces which place each shim 72' in what may be termed Ithoop tension". The "hoop tension" i8 greatest at the edges of the shims 72' adjacent the high pre~sure side 64bl of the flexible element 62bl. The tension diminishes with increasing distance from the longitudinal axis of the pipe joint assembly 30. Thus, the ends of the shims 72' which are uppermost in Figure 4 are 15 subject to a lesser "hoop tension" than the lower ends of the shims. The smaller tlhoop tension" requires a smaller thick-ness of metal to resist the tension load and the shims may be tapered accordingly.
It will be understood that the embodiment desoribed above is merely exemplary and that persons skilled in the art may make many variations and modifications without departing from the splrit and scope of the invention. For example, indivldual rings 58 and 60 may be fabricated in one piece with ad~acent metal oomponents such as flanges 46. The ~oints 56 may also be utilized as combined bearings and seals in a variety of dif~erent pipe ~oint assemblies~ suoh as those shown in the var~ous Figures of Herbert etal U. S. Patent No. 3,6Bo,8g5. ~11 such modifications and variations are intended to be within the scope of the invention as defined in the appended claim~.
.
Claims (24)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. In a pipe joint assembly for fluid conduits that receive fluid under a pressure greater than an external ambient pressure on the conduits, said assembly comprising a cylindrical housing including an annular housing body and an annular flange at each end extending radially inwardly of said housing body, and a pair of tubular members of smaller diameter than said housing, each tubular member including a flange at one end extending radially outwardly of said member, said flanges of the tubular members being disposed between the flanges of the housing and the other ends of the tubular members projecting from opposite ends of the housing for attachment to fluid conduits, the improvement of two annular joints disposed within the housing, each joint comprising:
(a) a pair of spaced rigid rings, and (b) an annular flexible element disposed between the rings and sealingly engaging opposed surfaces of the rings so as to define a pair of annular exposed side surfaces of said flexible element, the flexible element including a body of elastomer which when measured substantially normal to at least one of the opposed surfaces of the rings has a tapered thickness between the rings that decreases from one side surface to the other side surface of the flexible element, the body of elastomer being closely confined in its tapered configuration along surfaces that extend from the one side surface to the other side surface of the flexible element so as to resist deflection of the elastomer from between the rings in response to pressure exerted on the one side surface of the flexible element, one ring of one joint being in load and motion transmitting engagement with the flange of one tubular member and being sealingly engaged with said one tubular member, one ring of the other joint being in load and motion transmitting engagement with the flange of the other tubular member and being sealingly engaged with said other tubular member, the other ring of each joint being sealing engaged with a fluid-tight portion of the pipe joint assembly such that the two joints together define at least part of a fluid-tight passageway that interconnects the tubular members to permit a flow of fluid between the tubular members, the joints being oriented such that the one side surface of each flexible element is exposed to fluid in said passageway and to pressure exerted by fluid in the passageway, the one side surface being the only side surface of each flexible element which is exposed to fluid in said passageway, each flexible element resiliently accommodating relative motion between the rings that engage the element and providing a fluid-tight seal that is particularly resistant to pressure exerted on the one side surface of the element.
(a) a pair of spaced rigid rings, and (b) an annular flexible element disposed between the rings and sealingly engaging opposed surfaces of the rings so as to define a pair of annular exposed side surfaces of said flexible element, the flexible element including a body of elastomer which when measured substantially normal to at least one of the opposed surfaces of the rings has a tapered thickness between the rings that decreases from one side surface to the other side surface of the flexible element, the body of elastomer being closely confined in its tapered configuration along surfaces that extend from the one side surface to the other side surface of the flexible element so as to resist deflection of the elastomer from between the rings in response to pressure exerted on the one side surface of the flexible element, one ring of one joint being in load and motion transmitting engagement with the flange of one tubular member and being sealingly engaged with said one tubular member, one ring of the other joint being in load and motion transmitting engagement with the flange of the other tubular member and being sealingly engaged with said other tubular member, the other ring of each joint being sealing engaged with a fluid-tight portion of the pipe joint assembly such that the two joints together define at least part of a fluid-tight passageway that interconnects the tubular members to permit a flow of fluid between the tubular members, the joints being oriented such that the one side surface of each flexible element is exposed to fluid in said passageway and to pressure exerted by fluid in the passageway, the one side surface being the only side surface of each flexible element which is exposed to fluid in said passageway, each flexible element resiliently accommodating relative motion between the rings that engage the element and providing a fluid-tight seal that is particularly resistant to pressure exerted on the one side surface of the element.
2. A pipe joint assembly, according to claim 1, wherein each annular flexible element is bonded to each of the corresponding rigid rings.
3. A pipe joint assembly, according to claim 1, wherein the one side surface of each flexible element is the radially innermost of its side surfaces.
4. A pipe joint assembly, according to claim 1, wherein each flexible element also includes a plurality of spaced annular shims of substantially inextensible material embedded in the body of elastomer, the thickness of the body of elastomer being exclusive of the thicknesses of the shims.
5. A pipe joint assembly, according to claim 4, wherein each shim has a thickness which decreases from the one side surface of the flexible element to the other side surface.
6. A pipe joint assembly, according to claim 4, wherein each shim and each body of elastomer is annular in one plane and arcuate in a plane perpendicular to said one plane.
7. A pipe joint assembly, according to claim 6, wherein the arcuate configuration of each shim is defined by an arc of a circle.
8. A pipe joint assembly, according to claim 7, wherein each shim and each body of elastomer is a spherically shaped annulus.
9. A pipe joint assembly, according to claim 1, which also includes an annular laminated bearing fabricated of alternating annular layers of elastomeric material and substantially inextensible material disposed between each flange of the housing and an adjacent flange of a tubular member, the two annular joints being disposed between the flanges of the tubular members with the other rigid rings of the two joints sealingly engaging one another.
10. In a pipe joint assembly for a conduit that receives fluid under a pressure greater than an external ambient pressure on the conduit, said assembly comprising a first annular member including a radially extending flange, and a second annular member spaced from and axially aligned with the first annular member, the second annular member including a radially extending flange that is spaced from and disposed in opposed relation to the flange of the first annular member, the improvement of an annular joint disposed between said flanges, said joint being fluid-tight and comprising an annular flexible element having a pair of annular exposed side surfaces and a pair of annular and opposed and surfaces, the flexible element including (a) a body of elastomer which when measured substantially normal to at least one of the end surfaces of the flexible element has a tapered thickness that decreases from one side surface to the other side surface of the element, the body of elastomer being closely confined in its tapered configuration along surfaces that extend from the one side surface to the other side surface of the flexible element so as to resist deflection of the elastomer from between the flanges in response to pressure exerted on the one side surface of the flexible element, and (b) a plurality of spaced annular shims of a substantially inextensible material embedded in the body of elastomer, the thickness of the body of elastomer being exclusive of the thicknesses of the shims, the joint being in load transmitting engagement with the flange of at least one of the first and second annular members and the end surfaces of the flexible element of the joint being sealingly engaged with fluid-tight portions of the pipe joint assembly so that the flexible element defines at least part of a fluid-tight passageway that interconnects the annular members to permit a flow of fluid between the annular members, the joint being oriented such that the one side surface of the flexible element is exposed to fluid in the passageway and to pressure exerted by fluid in the passageway, the one side surface being the only side surface of the flexible element which is exposed to fluid in the passageway, the flexible element resiliently accommodating relative motion between the annular members and providing a fluid-tight seal that is particularly resistant to pressure exerted on the one side surface of the flexible element.
11. A flexible joint for a conduit that receives fluid under a pressure greater than an external ambient pressure on the conduit, said joint comprising a pair of spaced rigid rings, and an annular flexible element disposed between the rings and sealingly engaging opposed surfaces of the rings so as to define a pair of annular exposed side surfaces of said flexible element, the flexible element including a body of elastomer which when measured substantially normal to at least one of the opposed surfaces of the rings has a tapered thickness between the rings that decreases from the radially innermost one of the side surfaces to the other side surface of the flexible element, the body of elastomer being closely confined in its tapered configuration along surfaces that extend from the one side surface to the other side surface of the flexible element so as to resist deflection of the elastomer from between the rings in response to pressure exerted on the one side surface of the flexible element, the flexible element resiliently accommodating relative motion between the rings that engage the element and providing a fluid-tight seal that is particularly resistant to pressure exerted on the one side surface of the element.
12. A joint, according to claim 11, wherein the annular flexible element is bonded to each of the rigid rings.
13. A joint, according to claim 11, wherein the flexible element also includes a plurality of spaced annular shims of a substantially inextensible material embedded in the body of elastomer, the thickness of the body of elastomer being exclusive of the thicknesses of the shims.
14. A joint, according to claim 13, wherein each shim has a thickness which decreases from the one side surface of the flexible element to the other side surface.
15. A joint, according to claim 13, wherein each shim and the body of elastomer are annular in one plane and arcuate in a plane perpendicular to said one plane.
16. A joint, according to claim 15, wherein the arcuate configuration of each shim is defined by an arc of a circle.
17. A joint, according to claim 16, wherein each shim and the body of elastomer are spherically shaped annuli.
18. A flexible-joint for a conduit that receives fluid under a pressure greater than an external ambient pressure on the conduit, said joint being fluid-tight and comprising an annular flexible element having a pair of annular exposed side surfaces and a pair of annular and opposed end surfaces, the flexible element including (a) a body of elastomer which when measured substantially normal to at least one of the end surfaces of the flexible element has a tapered thickness that decreases from the radially innermost one of the side surfaces to the other side surface of the flexible element, and (b) a plurality of spaced annular shims of a substantially inextensible material embedded in the body of elastomer, the thickness of the body of elastomer being exclusive of the thicknesses of the shims, the joint resiliently accommodating relative motion between adjacent sections of conduit and providing, when sealingly engaged with said adjacent conduit sections, a fluid-tight seal that is particularly resistant to pressure exerted on the one side surface of the flexible element.
19. A pipe joint assembly, according to claim 10, wherein the annular flexible element is bonded to the fluid-tight portions of the pipe joint assembly with which the flexible element is sealingly engaged.
20. A pipe joint assembly, according to claim 10, wherein the one side surface of the flexible element is the radially innermost of its side surfaces.
21. A pipe joint assembly, according to claim 10, wherein the shims and the body of elastomer are annular in one plane and arcuate in a plane perpendicular to said one plane.
22. A pipe joint assembly, according to claim 21, wherein the shims and the body of elastomer are spherically shaped annuli.
23. A joint, according to claim 18, wherein the shims and the body of elastomer are annular in one plane and arcuate in a plane perpendicular to said one plane.
24. A joint, according to claim 23, wherein the shims and the body of elastomer are spherically shaped annuli.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US62143375A | 1975-10-10 | 1975-10-10 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1040230A true CA1040230A (en) | 1978-10-10 |
Family
ID=24490160
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA261,915A Expired CA1040230A (en) | 1975-10-10 | 1976-09-23 | Flexible sealing joint |
Country Status (7)
| Country | Link |
|---|---|
| JP (2) | JPS5248120A (en) |
| AU (2) | AU509835B2 (en) |
| CA (1) | CA1040230A (en) |
| DE (1) | DE2645515C2 (en) |
| FR (1) | FR2327482A1 (en) |
| GB (2) | GB1553096A (en) |
| NL (1) | NL177242C (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4121861A (en) * | 1977-04-29 | 1978-10-24 | Lord Corporation | Flexible sealing joint |
| GB1582616A (en) * | 1977-04-29 | 1981-01-14 | Lord Corp | Liquid filled flexible conduit joint |
| JPS5848461Y2 (en) * | 1978-03-08 | 1983-11-05 | 株式会社ブリヂストン | Wear resistant flexible joint tube |
| US4746247A (en) * | 1987-01-30 | 1988-05-24 | Lockheed Corporation | Stabilizing ring for interlocking load ring/back flange interface |
| FR2925105B1 (en) | 2007-12-18 | 2010-01-15 | Inst Francais Du Petrole | UPLINK COLUMN WITH FLANGED AUXILIARY PIPES AND CONNECTIONS IN BAIONNETTE. |
Family Cites Families (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US502038A (en) * | 1893-07-25 | Pipe-coupling | ||
| US1925335A (en) * | 1930-12-12 | 1933-09-05 | Nat Supply Co | Ball joint steel hose coupling |
| US2713503A (en) * | 1950-03-08 | 1955-07-19 | Chicago Metal Hose Corp | Reinforced expansion joint |
| US3071422A (en) * | 1959-08-10 | 1963-01-01 | William L Hinks | Continuous strip type of static load bearing |
| US3179400A (en) * | 1963-06-11 | 1965-04-20 | Lord Mfg Co | Torsion spring |
| US3390899A (en) * | 1965-03-15 | 1968-07-02 | Lockheed Aircraft Corp | Flexible joint means |
| DE1945523A1 (en) * | 1969-09-09 | 1971-03-11 | Martin Herter | Ball joint pipe connection |
| US3680895A (en) * | 1969-11-24 | 1972-08-01 | Lockheed Aircraft Corp | Flexible joint means |
| US3734546A (en) * | 1972-03-30 | 1973-05-22 | Lockheed Aircraft Corp | Flexible pipe connection |
| US3848899A (en) * | 1973-02-16 | 1974-11-19 | Dumont Aviat Ass | Pneumatic swivel assembly |
| JPS5181791A (en) * | 1975-01-13 | 1976-07-17 | Osaka Koon Denki Kk | IONKAPUREETEINGUHOHO |
| US4068868A (en) * | 1975-09-02 | 1978-01-17 | Vetco Offshore Industries, Inc. | Flexible joints for marine risers |
-
1976
- 1976-09-23 CA CA261,915A patent/CA1040230A/en not_active Expired
- 1976-09-30 AU AU18256/76A patent/AU509835B2/en not_active Expired
- 1976-09-30 AU AU18256/76A patent/AU1825676A/en not_active Expired
- 1976-10-06 GB GB41416/76A patent/GB1553096A/en not_active Expired
- 1976-10-06 GB GB42991/78A patent/GB1553097A/en not_active Expired
- 1976-10-08 JP JP51121198A patent/JPS5248120A/en active Pending
- 1976-10-08 NL NLAANVRAGE7611153,A patent/NL177242C/en not_active IP Right Cessation
- 1976-10-08 DE DE2645515A patent/DE2645515C2/en not_active Expired
- 1976-10-11 FR FR7630434A patent/FR2327482A1/en active Granted
-
1982
- 1982-07-05 JP JP1982101700U patent/JPS5860086U/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| DE2645515C2 (en) | 1984-07-19 |
| GB1553096A (en) | 1979-09-19 |
| NL177242C (en) | 1985-08-16 |
| JPS5860086U (en) | 1983-04-22 |
| FR2327482A1 (en) | 1977-05-06 |
| JPS5248120A (en) | 1977-04-16 |
| FR2327482B1 (en) | 1983-04-29 |
| NL177242B (en) | 1985-03-18 |
| JPS6319674Y2 (en) | 1988-06-01 |
| NL7611153A (en) | 1977-04-13 |
| AU509835B2 (en) | 1980-05-29 |
| DE2645515A1 (en) | 1977-04-21 |
| AU1825676A (en) | 1978-04-06 |
| GB1553097A (en) | 1979-09-19 |
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