JPH0158397B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF INDUSTRIAL APPLICATION The present invention relates to pipe connection fittings, particularly, but not exclusively, for use in submarine pipe installations.

BACKGROUND OF THE INVENTION A need often arises for non-welded permanent pipe connection fittings for subsea and surface applications. Furthermore, especially for subsea applications, a telescoping feature is also required for pipe connection fittings, which allows adjacent connections to be separated.

In subsea template or manifold-based equipment installed on the seabed, subsea flow lines are installed from a platform or land-based facility. In the case of deep sea installations, due to the complexity of operation, it is common to run the line to its final position, hold it at a connection, and then make the final connection to the manifold or template pipe system as a separate operation. There are several ways to make this final connection, but in all cases, the pipe ends are separated, a seal or seal retaining member is inserted between them, and then they are brought together and the pipe ends are pressure clamped. It's normal.

Therefore, when making the final connection, a means is required to separate and widen the pipe ends. Telescoping joints have been proposed in the past for this purpose, but despite their substantial advantages, they have been subject to severe criticism in two respects. Firstly, the long-term effectiveness of the resilient sealing member required to prevent leakage is not guaranteed, and secondly, the fittings generally must be restrained to avoid separation due to end pressure.

In order to avoid the problems associated with telescoping fittings, the current state of the art for subsea installations is to use flexible pipe spools or flex loops in manifold pipe systems that bend appropriately to separate the ends of the pipes to be connected. It is common to include it in the structure.

As will be appreciated by those skilled in the art, this method requires the use of large bent pipes to provide the required bends without overstressing the pipe loops. The desired effect can also be achieved by modification of the outboard subsea flowline, which allows the dimensions of the template and manifold structures to be reduced, but successful back modification of the flowline to make the final connection. It is difficult to predict whether this will happen or not, and the success of this operation cannot be guaranteed at all.

Problems to be Solved by the Invention Therefore, an object of the present invention is to provide a metal seal for underwater equipment that can be designed as a telescoping pipe connection joint, in order to solve the above-mentioned problems of the conventional telescoping joint for underwater equipment. To provide pipe connection fittings with.

Means for Solving the Problems A pipe connection fitting according to the invention provides a tight fitting that provides a seal against leakage from the fitting and a friction lock to prevent axial separation of the inner and outer fitting members from each other under intended operating pressure conditions. The inner and outer joint members are telescopically fitted coaxially on the inside and outside through a fit, and one joint member is provided with a duct that can be connected externally and reaches the contact interface between the two joint members, and a duct is provided in one joint member to allow pressurized fluid to flow through the inner and outer joint members. This makes it possible to release the friction lock and allow telescopic relative movement of both joint members. An interference fit in which one coupling member is placed inside the other produces a pressure utilization effect due to an increase in the internal working pressure that tends to expand the inner coupling member at the contact interface, which improves sealing efficiency and Both friction locking efficiency can be increased.

Seal members may be attached to both ends of the contact interface to provide an interference fit. These seal members limit the frictional lock release hydraulic pressure introduced through the duct, and may be made of elastomer or metal. In the latter case, the sealing member or sealing surface may be formed by machining the coupling member itself. These sealing members, except for those portions which are planar sealing surfaces, are incidental to normal operation of the joint on which the interference fit seal operates.

Preferably, the outer joint member is provided with a stepped counterbore for receiving the inner joint member.

Operation In joints that do not utilize a telescoping extension connection operation and a telescoping contraction separation operation, the entire length of the counterbore preferably provides an interference fit, with the mating outer circumferential surface of the inner joint member attached to the counterbore. be complementary to In this case, the stepped structure facilitates the initial assembly of the joint, partially joining the inner and outer joint members before forming an interference fit, and preferably connecting the sealing member to the inner end of the inner joint member and the outer joint member. provided at each outer end of the member.

When the length of the joint is telescopically variable, when a suitable fluid pressure is applied from the outside through the duct, the outer portion of the counterbore in the outer joint member The inner joint member may have a reduced diameter inner end sleeve portion slidably mated with the lower end portion to provide the required interference fit for the inner joint member. This allows the portions of the through-holes in both joint members that are exposed when the joint is fully retracted to have the same diameter, providing a nearly continuous through-hole in the operating state when the joint is extended, and allowing the pig to passage through the fitting without losing full dynamic sealing contact to the through-hole. A wiper/protective seal ring is preferably provided to prevent solid matter from entering between the counterbore and the sleeve, and a second wiper/protective seal ring is provided at the inner end of the contact interface. It may be placed in

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention will now be explained in detail with reference to the accompanying drawings showing two preferred embodiments in axial section.

The upper half of Figure 1 shows the pipe fitting in a fully retracted condition, and the lower half of the figure shows the pipe fitting in a fully extended, operational condition.

The joint of FIG. 1 has an outer joint member 1 and an inner joint member 2 that fit inside and outside in a telescoping manner. The outer joint member 1 has a through hole 3 with the same diameter as the pipeline in which the joint is used, and the inner joint member 2 also has a through hole 4 with the same diameter. The stepped counterbore portion of the outer joint member 1 has a medium diameter portion 5 and a large diameter end portion 6. An annular groove 7 is provided in the intermediate portion of this counterbore of the outer joint member 1 .

A complementary step is formed on the outer periphery of the inner joint member 2 . A seal 9 formed inwardly of the relief groove 8 of the inner joint member 2 provides an "interference fit" within the large diameter end 6 of the outer joint member counterbore. This provides both a leak-tight seal from the eyelid joint and a nested friction lock to prevent relative movement of the joint members 1, 2. In particular, it prevents the joint from bursting due to internal working pressure.

An elastic inner seal 11 and an outer seal 12 are provided between the inner and outer joint members 1 and 2 at both end positions of the contact interface part 10 that provides an interference fit, and the inner seal 11 is bitten into the outer joint member 1. , the outer seal 12 is bitten into the inner joint member 2. The inner end sleeve portion 13 of the inner joint member 2 is slidably fitted into the middle diameter portion 5 of the outer joint member 1. This allows the permanently exposed part of the hole to become an almost continuous hole, as shown in the lower part of FIG. 1, and the thin sleeve section 13 bridges the groove 7 so that pigs can and both coupling parts 3 and 4 without losing the dynamic sealing contact between them.

The wiper and protection seal 14 is attached to the outer joint member 1.
It is provided between the outer end of the medium diameter portion 5 and the sleeve portion 13. As shown in the lower half of FIG. 1, this seal 14 is wedged into the outer joint member 1, placing the seal 14 near the inner or free end of the sleeve portion 13 when fully engaged and extended. A second wiper/protection seal 15 is inserted into the outer joint member 1 inside the seal 11 to provide second protection for the contact interface portion 10.

The duct 16 in the inner joint member 2 has an external connection port 17 and a peripheral groove 19 in the contact interface 10.
It reaches the boat 18 that communicates with. This duct 1
When pressure fluid is supplied to 6, this pressure fluid separates both joint members 1 and 2 at the contact interface part 10,
Both joint members 1 and 2 are removed by releasing the interference fit.
Allows nested movement between each other. The maximum range or stroke of mutual extension of the joint members is designated by the symbol S.

The pipe connection fittings described above are of the type that are incorporated into subsea pipe installations close to the inboard/outboard seal connections of subsea template or manifold systems.
During installation, one of the two coupling members 1, 2 is welded to the template or manifold pipe device,
The other end is welded to the corresponding connecting flange or hub. When retracting the outboard flowline, it may be necessary to retract the inboard piping system. If the outboard hub is fixed downwards, feed the connecting tool into position, position both the inboard and outboard hubs, and at the same time use the probe receiver for the hydraulic stroke.
Plug in and connect to. This pressure receiver, not shown, may be permanently connected to the external connection port 17 for the joint hydraulic stroke.

Although this coupling was primarily designed for deep sea use as a means of remote connection without the need for a diver, it may also be used for connection by a diver in shallow water.

For stroking the joint, a suitable high pressure is applied to the stroke boat 18 which forces the joint members 1, 2 apart and allows telescopic mutual free movement between them to reach the extended position. Once the pipe fittings are finally connected, a pressure equal to the operating internal pressure is applied via the stroke boat 18 to pressure test the pipe fittings. Since the interference fit is maintained up to the resilient stroke seal or outer seal 12, the pipe fitting pressure restraint test is performed on the surface that abuts the stroke inlet port groove or circumferential groove 19. Further, an outer circumferential groove 20 is provided in the contact interface portion 10 of both the joint members 1 and 2. These facilitate the distribution of pressure fluid in this area,
When the joint is unlocked by applying external pressure to the external connection port 17, it acts as an anti-lock groove to equalize the pressure.

It is understood that in a practical installation both the inboard and outboard pipe systems would likely be securely secured. In this case, the frictional locking resistance caused by the interference fit between the two joint members 1 and 2 only needs to be addressed by the difference in pressure receiving area between the pipe hole and the sliding contact interface diameter. There is no need to deal with the sum of the total pressure receiving area and the differential area of the inner pipe.

Although the coupling of FIG. 1 has been described as being attached to a template or manifold arrangement, it will be appreciated that it also has advantages for intermediate connections in subsea flow lines. In this case, the coupling can be installed on the seabed over the entire length of the pipeline by a method of remotely connecting the entire length of the pipeline on the seabed without the use of large-scale enlarged pipe loops.

Although the joint of the present invention has a simple structure,
It has considerable flexibility and works effectively as long as its final operating position is within a fairly wide tolerance.
The tendency of the pipe to move due to pressure end load only increases the preset load of the flow line connection. Compared to current common practice in the art, the joint according to the invention can be replaced with an equivalent 360° bend having a diameter at least four times the length of the present joint.

A flexible shroud 21 is installed to protect the surface portion of the inner joint part 2 which enters the outer joint part 1 during the connection process, which surface part would otherwise be exposed. This prevents crusting on the surface areas which would interfere with the connection process after a period of operation on the seabed. One end of the cover 21 is fixed to the outer circumference of the outer joint member 1 by a clamp ring 22, and the other end is fixed to the outer circumference of the inner joint member 2 by a clamp ring 23.

The embodiment of FIG. 2 is basically similar to that of FIG. 1, but is simplified in that it eliminates the possibility of telescoping expansion under pressure. Equivalent basic parts in this embodiment are designated by the reference numerals used in FIG. 1 plus 100. Outer joint member 101 and inner joint member 10
2 each have through holes 103 and 104 with the same diameter corresponding to the diameter of the pipeline into which the joint is to be fitted. In the illustrated state after coupling, the inner end of the inner joint member 102 is in contact with the inner end stepped portion 130 of the stepped counterbore portion consisting of the medium diameter portion 105 and the large diameter end 106 of the outer joint member 101. come into contact with In this case, the annular groove 7 in FIG. 1 is omitted, and the outer joint member 101 and the inner joint member 102 are interference-fitted over the entire length of the counterbore portion, that is, both the medium diameter portion 105 and the large diameter end portion 106. be done.

Therefore, the inner seal 111 and the outer seal 11 are arranged at both ends of the contact interface to achieve an interference fit.
2 are relatively widely separated. In this case, inner seal 1
11 is attached to the inner end of the inner joint member 102 and the outer seal 112 is attached to the outer end of the outer joint member 101. The medium diameter part 105 and the large diameter end 106 of the counterbore have approximately equal effective lengths, and a relatively short radial duct 116 and external connection port 11
7 is formed on the outer joint member 101 at the center of the large diameter end 106. A circumferential groove 119 communicating with the duct 116 at the contact interface is formed in the outer joint member 101 in this case. In addition, several spaced circumferential grooves 120 are provided in the counterbore large diameter end 106 and in this case interference fit of the inner coupling member 102 to facilitate the distribution of external pressure fluid at the contact interface. Several pieces are formed in the sleeve part 113.

To assemble this joint, the inner joint member 102 is partially inserted into the outer joint member 101 until the inner seal 111 enters the counterbore medium diameter section 105, at which time the outer seal 112 also engages with the inner joint member 102. to engage. Here, fluid pressure is introduced between the joint members 101 and 102 from the outside via the external connection port 117 and the duct 116.
This fluid pressure is localized between both seals 111 and 112, and pushes the cylindrical engagement portions of both joint members apart in the radial direction, expanding outer joint member 101 and contracting inner joint member 102. This allows both coupling members 101, 102 to be fully pushed together into the normal operating position shown in FIG. 2, providing a permanent metal seal joint upon release of applied fluid pressure and providing an interference fit in accordance with the present invention. A metal seal and friction lock is realized using a composite cylindrical arrangement.

Once assembled, the fitting is subjected to a pressure test via external port 117 at a pressure lower than the pressure required to separate the fitting members, i.e., an internal operating pressure. When internal operating pressure is applied, the effect of increased hoop stress in the cylindrical portion of the outer joint member 101 surrounding the inner joint member 102 enhances the pressure seal and friction locking effect, resulting in a pressure-based seal.

Thereafter, when it becomes necessary to disassemble the joint, fluid pressure is applied through the external connection port 117 to separate the connecting members 101 and 102 in the radial direction so that they can be separated in the axial direction. Although this connection joint has a simplified structure, it has high speed of connection and separation work, possibility of external pressure test on the joint,
It has general advantages such as a dimensionally small profile.

In the embodiments described above, the elastic inner seal 11 or 111 may be omitted depending on the situation. In this case, the application of a test pressure via the external connection 17 or 117 ensures the integrity of the interference fit between the two coupling members 1, 2, provided that the coupling in question "holds" that pressure. provide proper verification. If the duct 16 of the first embodiment is compatible with the installation method, the duct 16 of the first embodiment can be replaced with the second embodiment.
It is also possible to provide a radial passage through the outer joint member 1, similar to the duct 116 in the illustrated embodiment.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a telescoping telescoping pipe fitting particularly suitable for underwater installations, and FIG. 2 is a cross-sectional view of a non-retractable pipe fitting suitable for underwater and floating installations. 1,101... Outer joint member, 2,102...
Inner joint member, 3, 4, 103, 104... Through hole, 5, 105... Medium diameter portion, 6, 106... Large diameter end, 7... Annular groove, 8... Relief groove, 9... Seal part, 10... Contact interface part, 11, 111... Inner seal, 12, 112... Outer seal, 13,
113... Sleeve portion, 14, 15... Protective seal, 16, 116... Duct, 17, 117...
External connection port, 18... Boat, 19, 119...
Peripheral groove, 20, 120... Outer groove, 22, 23...
...clamp ring.

Claims (1)

Claims: 1. Connecting the inner and outer joints through an interference fit that provides a seal against leakage from the joints and a friction lock to prevent axial separation of the inner and outer joint members from each other under intended operating pressure conditions. The members are fitted coaxially inside and outside in a telescoping manner, and a duct is provided in one of the joint members that enables external connection and reaches the contact interface between the two joint members. A pipe connection joint characterized by allowing nested relative movement of joint members. 2. A pipe connection joint according to claim 1, characterized in that a sealing surface is formed by machining both joint members. 3. In the joint described in claim 1 or 2, sealing members are fitted or formed by machining on both ends of the contact interface portion that forms an interference fit between the two joint members, and both sealing members A pipe connection joint characterized in that it maintains friction lock release fluid pressure applied through the duct. 4. The pipe connection joint according to claim 3, wherein the seal member is an elastic seal member or a metal seal member machined from the joint member. 5. In the joint according to any one of claims 1 to 4, the duct communicates with the outer circumferential groove of the contact interface, and the outer circumferential groove communicates with the outer circumferential groove of the joint member in which the duct is formed. A pipe connection joint characterized in that it is formed on the surface or inside. 6. A pipe connection joint according to any one of claims 1 to 5, characterized in that the outer joint member has a stepped counterbore. 7. The joint according to claim 6, wherein substantially the entire length of the stepped counterbore forms the interference fit, and the inner joint member has an outer circumferential surface that is a complementary fit. Pipe connection fittings. 8. The pipe connection joint according to claim 3 or 7, wherein the sealing member is provided at the inner end of the inner joint member and the outer end of the outer joint member, respectively. . 9. The pipe connection joint according to claim 7 or 8, wherein the duct is formed on an outer joint member. 10 In the joint described in claim 6, the length of the joint is variable in a telescoping manner when an appropriate fluid pressure is applied from the outside through the duct, and the counterbore of the outer joint member is an outer end of the portion forming the interference fit with the inner joint member, the inner joint member having a reduced diameter inner end sleeve portion that is slidably engaged with the inner portion of the counterbore. A pipe connection fitting characterized by: 11 In the joint described in claim 10, the portions of the through holes in both joint members that are exposed when the joint is completely contracted have the same diameter and are substantially continuous under long-term operating conditions. A pipe connection joint characterized by forming a through hole. 12. In the joint according to claim 10 or 11, a wiper and protective seal is provided to prevent solid matter from entering between the counterbore portion and the sleeve portion of the inner joint member. A pipe connection fitting characterized in that it is attached. 13. The pipe connection joint according to claim 12, characterized in that a second wiper/protective seal is attached to the inner end of the contact interface where the interference fit is formed. 14. A pipe connection joint according to any one of claims 10 to 13, characterized in that the duct is formed within the inner joint member. 15 In the joint according to any one of claims 10 to 14, a flexible cover is attached between both joint members, and when the joint of the inner joint member is in an extended state, the outer joint member A pipe connection fitting characterized in that said covering surrounds a portion which is external to the member but is received within the outer fitting member when the fitting is in a fully retracted state. 16. In the joint according to any one of claims 1 to 15, a groove is provided in the contact interface portion of both joint members that provides the interference fit, and the fluid introduced through the duct is provided with a groove. A pipe connection joint characterized in that it promotes pressure distribution within the contact interface.