JPS6319674Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a flexible pipe joint for connecting conduits carrying pressurized fluid.

In recent years, effective methods have been developed for drilling oil and gas wells underwater. In this method, these oil or gas wells are drilled so that the drilling head is located at a sufficient depth that it does not pose a hazard to navigating ships (on or near the ocean floor). Such offshore or underwater wells are dug from a vessel, such as a drilling vessel, or from a platform supported on multiple legs that stands on the ocean floor.

Ships such as drilling ships are particularly susceptible to wave motion, even if they are anchored. Excavation performed from a floating vessel must therefore accommodate the lateral and vertical movements of the vessel. Drilling equipment reaching the seabed from the ship, such as the drilling string and sampling pipes, should therefore have some degree of freedom to avoid being destroyed when the drilling ship moves slightly from its position. Must be. In particular, the pipes in the drilling string are given sufficiently small diameters and lengths to avoid damage. The sampling pipe or subsea introduction pipe may also have a relatively large diameter and house a drilling string that directs the excavated mud up the annulus between the internal wall of the sampling pipe and the external wall of the string. It's summery. Therefore, the sampling pipe, which has a larger diameter and greater stiffness than the drilling string, should have at least one coupling or joint to be sufficiently flexible and to withstand internal and external fluid pressures and be able to withstand the sampling process. Constructed to withstand friction from fluids passing through the pipe, drilling tools, etc.

One type of flexible joint traditionally used in sampling pipes consists of a ball with a precision-machined spherical surface and a socket with a complementary spherical surface, also precisely machined. flex by sliding one against the other. Further, the interface between both spherical surfaces is sealed by an elastic O-ring.
The flexural movement of such ball joints is impaired when subjected to high pressures. Additionally, this joint has the problem that both the sliding surface and the O-ring seal wear and deteriorate, requiring frequent repair or replacement.

Flexible joints for fluid conduits, such as subsea collection pipes, include an annular flexible member disposed between flanges attached to the ends of the conduit sections. This flexible member is usually constructed from alternating layers of rigid and flexible bodies made of metal and elastomer. The shape of these layers or flakes may be flat-faced toroids, as in the pipe joint of Jonsson, U.S. Pat. No. 3,168,334, or as in the flexible joint of Herbert et al., U.S. Pat. No. 3,680,895. It is made into an annular body with a spherical surface. The use of a layered flexible member allows the necessary flexural movement of the joint and also acts as a seal.
Since this layered joint has no moving parts, it does not suffer from the wear and tear that occurs in the ball and socket joints described above.

Joints using layered flexible members do not suffer from the wear problems of typical ball and socket joints, but are prone to rupture or weakening when subjected to high axial loads and high pressure differentials. . In particular, the elastomeric layer of the layered member can withstand high compressive loads but is relatively weak in tensile loads. Therefore, if a force acts that causes longitudinally adjacent pipes to move away from each other in the axial direction, this flexible member will be subjected to a tensile load and will be easily destroyed. In order to solve the problem of this tensile load, a tension bar that supports the tensile load is used to prevent the tensile load from acting on the flexible member. It has also been practiced to use a pair of layered flexible members at the joint so that at least one of them is always subjected to a compressive load regardless of relative movement in the longitudinal direction of the adjacent pipes. . By reducing the tensile load on the layered flexible member, the possibility of failure due to high pressure differentials can also be reduced. Furthermore, the pressure resistance of the layered member is also improved by adhering adjacent layers.

The present invention seeks to provide a flexible joint for a fluid conduit with an improved high pressure dynamic seal. According to the invention, the joint consists of a pair of spaced rigid rings arranged between adjacent ends of two conduits. An annular flexible member is fluid-tightly disposed between the rings, with both sides of the flexible member remaining exposed to the outside. The inner side of these sides is exposed to the pressurized fluid flowing through the conduit. This creates a pressure differential across the flexible member between the sides of the flexible member. To withstand the loads caused by this pressure difference, the flexible member has an elastomeric body that tapers in thickness from one side of the member to the other between the rigid rings. This tapered thickness reduction allows the elastomeric body to withstand fluid pressure in the conduit. In this way, the flexible member flexibly accommodates relative movement between the rings, that is, between the pipes, maintains fluid tightness between the rings, and forms a pressure-tight seal.

Further, according to the present invention, the flexible member also includes:
It has a plurality of spaced annular intermediate inserts constructed from a non-stretchable material embedded within an elastomeric body. This insert improves the compressive strength of the elastomeric body. When referring to the thickness of the elastomer body, it refers to the thickness excluding the thickness of the insert. The thickness of each insert may be constant or tapered. If the space between the rigid rings is tapered from the high pressure side to the low pressure side, and this space is wide enough even if the shape of the insert body is tapered,
The insert may be tapered in this direction.
When the spaces between the rigid rings have a constant spacing, for example, the insert may taper in thickness from the low-pressure side to the high-pressure side of the flexible member to obtain the required durability effect. I can do it.

In a preferred embodiment, each of the insert and the elastomer body is an annular body having an arcuate shape in a plane that includes the central axis and diameter of the annular body. Therefore, each of the insert and the elastomer body becomes a ring body having a spherical surface whose diameter increases sequentially from the inside.

The present invention relates to a flexible pipe joint assembly for joining two pipes. The assembly includes a cylindrical housing with a cylinder and an annular flange projecting radially inwardly at each end of the cylinder. A pair of tubes having a smaller diameter than the housing each have a flange at one end and are received within the housing such that the flanges of the tubes are disposed between the flanges of the housing. The other ends of these tubes each project outwardly from the flange of the housing. A pair of seal joints according to the present invention may be disposed between opposing flanges of the pair of tubes, or between the flanges of the tubes and the housing.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a drilling ship 10 floating on the surface 12 of the sea 14.
It shows. Below the vessel 10 is a submersible well head assembly 16 located on the ocean floor 18. The lower end of the large diameter sampling pipe 20 is connected to the assembly 16 by a connector 22. The upper end of the sampling pipe 20 is suitably fixed to the ship 10, for example by a cable 24. The cable 24 is
A sampling pipe 20 is positioned approximately in the center of a drilling slot 26 extending through the vessel 10. During a drilling operation, a string of drilling pipes 32 is passed from the rotary table 34 of the drilling vessel 10 through the sampling pipe 20 to the well.

Although the sampling pipe 20 is shown in FIG. 1 as a continuous pipe or tube, it typically consists of a number of short tubes secured together in any suitable manner. Near each end of the sampling pipe 20 is a flexible pipe joint assembly 28.
and 30 are arranged. Joint assemblies 28 and 30 accommodate large lateral movements of the sampling pipe caused, for example, by movement of drilling vessel 10. These flexible pipe joint assemblies 28 and 30 have substantially identical construction, so that the joint assembly 30 shown in FIG.
Only those will be explained in detail.

The pipe joint assembly 30 has a cylindrical outer housing 36 having a cylindrical body 38 open at both ends and a pair of flanges 40a and 40b. The flanges 40a and 40b are removably attached to both ends of the cylindrical body 38 by bolts 42, for example. When attached to barrel 38, flanges 40a and 40b will project radially inwardly of the barrel.

Adjacent to flange 40a of housing 36,
A tube 44a is placed so as to pass through the opening. A flange 46a is provided at one end of the tube 44a located inside the housing 36. The flange 46a projects radially outwardly from the tube 44a and overlaps the flange 40a of the housing 36. These flanges 40a and 46a
The flange 40a needs to be removable from the barrel 38 in order to allow this overlap. This allows assembly of tube 44a within housing 36.
A tube 44b similar to tube 44a having a flange 46b is located at the other end of housing 36, with flange 46b and flange 40b similarly overlapping. An annular replaceable bushing 43a, 43b, 45a, 45b, 47a and 47b covers the inner periphery of each tube 44. Bushes 43, 45 and 47 connect the well tool and sampling pipe 32 through the joint assembly 30.
The pipe 44 is protected from the frictional effects of drilling mud passing outside the pipe.

Between flanges 40a and 46a and flange 4
Between 0b and 46b is an annular flexible member 48a.
and 48b are respectively arranged. The flexible members 48a and 48b are formed by a pair of relatively strong annular plates 50a, 50b and 52a, 5, respectively.
2b and intermediate flexible members 54a, 54b.
It is made up of plates 50a, 50b and 52
a, 52b are flanges 40a, 40b and 46a, 4, respectively, having surfaces of approximately corresponding shapes.
It has been accepted by 6b. Each flange-to-plate interface is unsealed. Flexible member 54 is adhered to plates 50 and 52 and is formed from a plurality of alternating layers of an elastomeric material and a material that is less extensible or less extensible than the elastomeric material. . Preferably, this non-extensible layer is constructed from steel and the elastomer material is constructed from natural rubber. Other non-extensible or elastomeric materials may also be used. Other elastomeric materials include man-made rubber;
Other non-extensible materials include other metals, fiberglass, and reinforced plastics. Each layer of flexible member 54 and adjacent plates 50 and 52
is circular in longitudinal cross section. The generally spherical shape of flexible members 48a and 48b allows the flexible members to function as a universal joint between adjacent relatively rigid members (i.e., non-stretchable layers). Relative movement between the plates) is absorbed by the flexibility of the elastomer layer.

A pair of flexible joints 56a and 56 are located between flanges 46a and 46b of tubes 44a and 44b.
b is placed. Joints 56a and 5
6b each have two relatively hard and rigid rings 58a, 60a and 58b, 60b and an annular flexible member 62a and 62b, respectively. Flexible member 62 containing elastomeric material
a and 62b are flexible members 48a and 48
It is softer and more flexible than the flexible materials 54a and 54b of b. This flexibility or stiffness difference is achieved by using a softer elastomer or a flexible member having a lower shape factor than flexible members 54a and 54b. Flexible members 62a and 62
b is rings 58a and 60a or ring 58
a pair of exposed or free sides 64a and 66a or side 6 bonded to b and 60b;
4b and 66b. Flexible member 48a
and 48b, the flexible member 6
2a and 62b and the adjacent ring 58a
The surfaces of and 58b are circular in longitudinal section. Joints 56a and 56b, like flexible members 48a and 48b, function as universal joints.

Ring 58a of joints 56a and 56b
and 58b are received and engaged flanges 46a and 46b that are shaped to prevent radial displacement of the ring. Grooves 63a and 63b formed in opposing faces of flanges 46a and 46b receive flexible O-rings 65a and 65b (see also FIG. 3) that seal the interface between the flanges and the rings. The rings 60a and 60b are engaged and fitted together. The axially projecting annular flanges 68a and 68b of rings 60a and 60b axially overlap to prevent relative radial misalignment between the rings.
As best shown in FIG.
and 67b are formed on rings 60a and 60b and seal the interface of rings 60a and 60b.
9b is accepted. rings 58a, 58b,
Neither 60a nor 60b is fixed to the metal surface to which they are adjacent. O-ring 65
The sealing action of a, 65b and 69b is ensured by keeping the compressive load of joints 56a and 56b constant as described below.

As shown in FIG. 2, joint assembly 30
Once the various members of the tubes 44a and 44b are assembled, the exposed ends of tubes 44a and 44b are joined to adjacent ends of a sampling pipe (not shown). The sampling pipe 20 is normally held in tension over its entire length. This tensile load is transferred to the joint assembly 30, which in turn transfers the compressive load to the layered flexible members 48a and 48b. This load is applied to the flange 46
a and 46b and housing 36
can be conveyed to. The compressive load on flexible members 48a and 48b causes the elastomeric material in the flexible members to deflect so that flanges 46a and 46b of tubes 44a and 44b tend to move away from each other;
It also tries to move away from joints 56a and 56b. Flanges 46a, 46b and ring 58
The inner members of the joint assembly 30 are pre-biased to prevent such movement from destroying the seals of the interfaces between the rings 60a and 60b and between the rings 60a and 60b. Housing flanges 40a and 40
A load is applied in advance between b. This pre-biasing or loading of assembly 30 biases joints 56a and 56b rather than flexible members 48a and 48b due to the difference in stiffness of flexible members 54a, 54b and 62a, 62b.
Thus, when a tensile load on sampling pipe 20 is transferred to tubes 44a and 44b and flexible members 48a and 48b, the deflection of these flexible members completely relieves the compressive load on joints 56a and 56b. Not enough to do that. As a result, the O-rings 65a, 65b and 69b are
A constant compressive load seals the interface between flanges 46a, 46b and rings 58a, 58b and 60a and 60b. This pre-applied load also creates some degree of frictional engagement between adjacent metal surfaces, e.g. flange 46a.
This prevents relative rotation between the ring 58a or the flange 46b and the ring 58b.

The spherical shapes of the flexible members 48a and 48b and the spherical shapes of the joints 56a and 56b are as follows.
Allows for angular mismatch on either side of the joint assembly 30 between the two sampling pipes 20.
This angular misalignment of collection pipe 20 is accommodated by the flexibility of the elastomer in members 54a, 54b, 62a and 62b, as described above. The elastomers in flexible members 54a, 54b, 62a and 62b also absorb rotational movement about the longitudinal axis of sampling pipe 20. Flexible member 62
Upon deflection of a, 62b, the flexible member, for example, along the outside of the excavation pipe 32
(As discussed above, the flexible members 48a, 48b form a fluid-tight seal against the seawater surrounding the joint assembly 30.) (no need to form). Joints 56a and 5
The sealing action of joint 56b is easily achieved due to its unique design as described below for joint 56b.

As described above and shown in FIG.
The radially inner surfaces 64a, 64b of the flexible members 62a, 62b of a, 56b are typically exposed to high pressure fluids such as drilling mud. Drilling mud is
It has a considerably higher pressure than fluid pressure such as seawater. A surface 66 facing the inner surfaces 64a and 64b
a and 66b come into contact with this seawater. This pressure difference between the opposite sides of the flexible members 62a, 62b forces the flexible members radially outward between the rigid rings 58a, 58b and 60a, 60b. To counter this pressure difference, flexible members 62a and 62
b has an elastomer 70b tapered outward. As shown for joint 56b in FIG. 3, elastomer 70b is attached to high pressure side 64 of flexible member 62b
b toward the low pressure side surface 66b (ring 58
b and 60b) (measured approximately perpendicular to the curved surface of 60b). Although exaggerated in FIG. 3 for illustrative purposes, the tapered thickness of elastomer 70b is achieved by tapering the space between adjacent arcuate surfaces of rigid rings 58b and 60b. This taper effectively serves to resist radially outward and upward destructive movement of the elastomer supported between the two rings 58b and 60b. This positive mechanical interlock creates a more effective high pressure seal than similar joints that rely solely on adhesion between an elastomer and an adjacent metal component.

Improving the ability of the joint 56b shown in FIG. 3,
That is, a metallic intermediate insert 72 is inserted into the elastomer 70b between rings 58b and 60b to provide increased durability with respect to pressure differentials on the elastomer 70b and to reduce distortion of the elastomer given this pressure differential. embedded at intervals. Insert 72, which has little extensibility compared to elastomer 70b, is a continuous annular member with an arcuate longitudinal cross section. Preferably, this arc is a circular arc. This shape allows for ball-and-socket type operation of joint 56b and is more convenient to manufacture than other shapes. This arc may be a single circle of constant diameter, or it may be circles of different diameters such that the diameters of successively adjacent inserts increase from the nominal center of the joint. The distances between the individual inserts and between the end inserts and adjacent surfaces of rings 58b and 60b decrease from high pressure side 64b to low pressure side 66b of flexible member 62b. When the inserts are circular arcs, the interval between them can be tapered by shifting the center of the arc of each insert in the axial direction with respect to the center of the arc of the adjacent insert. The retention effect of joint 56b is obtained by reducing the spacing between rings 58b and 60b, but the elastomer 70
Other techniques may be used to taper the thickness of b. For example, the thickness of the insert 72 may vary from the low pressure side 66b of the flexible member 62b to the high pressure side 64 of the flexible member 62b.
It may be tapered towards b. In this case, the spacing between rings 58b and 60b is not tapered.

The use of tapered elastomers in flexible members is well known, as in FIG. 3 of Croix, U.S. Pat. No. 3,179,400 and FIG. 7 of Hinks, U.S. Pat. No. 3,071,422. However, none of the prior art recognizes the construction and use of such flexible members as sealed pipe joints.

FIG. 4 shows another embodiment of the joints 56a, 56b. In the embodiment of FIG. 4, the thickness of elastomer 70b' is greater than the thickness of flexible member 62.
In addition to tapering from high pressure side 64b' to low pressure side 66b' of flexible member 62b', insert 72' similarly tapers from the high pressure side to the low pressure side of flexible member 62b'. There is. The tapered shape of insert 72' reduces the amount of metal used in the flexible member compared to flexible member 62b of FIG. The reason for tapering the inserts 72' may be best understood from the fact that a radially directed force called hoop tension is applied to any portion of each annular insert. . That is, the annular tension is greatest at the end of the insert adjacent the high pressure side 64b' of the flexible member 62b'. This tension decreases as the distance from the longitudinal axis of the pipe joint assembly 30 increases. Therefore, the fourth
Each end of the insert 72', which is at the top in the figure,
It will experience less annular tension than at its lower end. If the annular tension is low, the metal will need to be thin to withstand this load, and the insert will therefore be tapered.

The embodiments described above are merely shown for convenience of explanation, and various modifications and changes can be easily made by those skilled in the art. For example, rings 58a, 58b, 60a and 60b can integrally form adjacent members such as flanges 46a and 46b.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a drilling ship located at sea, such as on a well head assembly on the seabed, and FIG. 2 shows one of the pipe joint devices shown in FIG. 1 and the present invention included therein. 3 is a vertical cross-sectional view including a partial cross-sectional view of the joint according to
The figure is an enlarged cutaway view of the joint shown in FIG. 2, and FIG. 4 is a view corresponding to FIG. 3 of another embodiment of the invention. 28, 30...Pipe joint device, 36...
...Housing, 38...Cylinder, 40a, 40b...
...Flange, 44a, 44b...Pipe, 46a, 4
6b...flange, 48a, 48b...flexible member, 50a, 50b, 58a, 58b, 60a,
60b...Plate or rigid ring, 54a, 54
b, 62a, 62b... flexible member, 70b...
Elastomer, 72...Insert.

Claims (1)

[Claims for Utility Model Registration] 1. A pipe joint device of a type in which a pair of spherical rigid rings are connected by a flexible member, which includes a cylindrical body 38 and a radially inward portion at both ends of the cylindrical body. annular flanges 40a, 40 protruding from
a cylindrical housing 36 having a cylindrical housing 36; and a cylindrical housing 36 having one end connected to both ends of the cylindrical housing 36, and flanges 46a and 46b protruding radially outward from the one end. A pair of small tubes 44a, 44
b, the respective flanges 46a and 46b of the pair of tubes are both located between the annular flanges 40a and 40b at both ends of the cylindrical body 38, and the other ends of the pair of tubes 44a and 44b are protruding from both ends of the housing 36,
In a pipe joint device for connecting pressurized fluid conduits, a pair of opposing annular joints 56a and 56b is provided between the flange of one pipe and the flange of the other pipe of the pair of pipes, and the annular joint (a) a pair of rigid rings 58a, 58b spaced apart from each other, one of which engages the annular flanges 46a, 46b; 60a, 60;
(b) This pair of rigid rings 58a, 58b; 6
0a, 60b are formed with annular flexible members 62a, 62b disposed between mutually opposing surfaces, and the flexible members 62a, 62b are connected to each of the rigid rings 58a, 58b; 60a, 60b. annular outer surfaces 66a and 66b which are fluid-tightly adhered to the mutually opposing surfaces and whose flexible members 62a and 62b are exposed radially outward;
and an annular inner surface 64 exposed radially inward.
a, 64b, and its inner surface 64
a, 64b are adapted to be in contact with the pressurized fluid; elastomer bodies 70b, 70b' embedded at a distance between the pair of rigid rings, and the thickness of the elastomer body excluding the thickness of the annular inserts 72, 72' is between the pair of rigid rings. The inner surface 6 when measured in a direction substantially perpendicular to at least one of the mutually opposing surfaces of the
4b, 64b' toward the outer surfaces 66b, 66b', the inserts 72, 72' and the elastomer bodies 70b, 70b' form an annular body;
A pipe joint characterized by being curved in a plane that includes the central axis and diameter of the annular body. 2. The curved inserts 72, 72'
2. The pipe joint according to claim 1, wherein the pipe joint has a circular arc shape. 3. The pipe joint according to claim 2, wherein the inserts 72, 72' and the elastomer bodies 70b, 70b' are spherical annular bodies.