NO345420B1

NO345420B1 - A multi-bore connector

Info

Publication number: NO345420B1
Application number: NO20190946A
Authority: NO
Inventors: Bjørn Pettersen
Original assignee: Subseadesign As
Priority date: 2019-08-01
Filing date: 2019-08-01
Publication date: 2021-01-25
Also published as: NO20190946A1; WO2021020972A1

Description

FIELD OF THE INVENTION

The present invention relates to a new connector for multi-bore connection in the oil and gas industry.

BACKGROUND

During oil/gas production injection systems, modules/pipelines are connected to obtain flow path between the reservoir and the host facilities. For such system efforts are made to reduce the number of connections by have several lines of various sizes gathered in one single connection, defined as multi-bore connection. At these connections flexibility is obtained by having long pipe sections/spools/flex loops to the connect modules/pipelines without overstressing the pipe or connection system. This results in larger and heavier modules for housing the long process piping. The costs for fabrication, transportation and installation will increase.

The long process pipes with small bore connections will be subjected to Flow Induced Vibrations (FIV). The natural frequency of the piping system is controlled by the mass and stiffness and when too low, the kinetic energy from the fluid flow turbulence will cause vibration induced fatigue to occur which may again cause critical pipe failure and consequence for pollution to the environment. Therefore, reducing the pipe length and spans to be within the maximum recommended for the avoidance of FIV will be an advantage and save costly additional FIV measures. Existing multi-bore connections are based on using heave tools/alignment structures to force the pipe work into final position and thereby making up the connector, which will leave large residual bending moments after release of the make-up tools.

US 2014/0361533 A1, which is owned by the present applicant, describes a pipe connector including: a first inner hub; a second inner hub; a sealing ring in contact with an inner surface of the said first inner hub and said second inner hub; a first outer hub in contact with an outer spherical surface of the first inner hub; a second outer hub in contact with an outer spherical surface of the second inner hub; and a clamping device which can be adjusted radially and axially to interface with external surfaces of the first and second outer hubs.

Other pipe connectors are described in WO 2011/150498 A1 and US 3957291 A.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a new connector for multi-bore connection in oil and gas industry allowing a certain misalignment angle without introducing alignment bending moments into the piping system during connection.

The scope of the invention appears from the appended claims.

In particular the multi-bore connector according to claim 1 includes a second hub with an external thrust ring with curved inner and outer surfaces, a first hub adapted to contact the inner surface of the second hub thrust ring, a sealing ring in contact with an inner spherical surface of the second hub and an inner surface of the first hub, a first coupler ring with a central opening for contacting the outer surface of the second hub thrust ring, a second coupler ring with a central opening for contacting an outer surface of the first hub, wherein the coupler rings are mounted face-to-face, a number of hydraulic couplers installed in the coupler rings, and a locking clamp adapted to force the coupler rings together, whereupon the coupler rings will press against the hubs and lock the hubs together.

The inventive multi-bore connection allows for a flexible solution during piping assembly/connection without requiring large spool lengths to prevent overstressing the pipe work and thereby increasing the piping systems natural frequency above the required threshold value to avoid FIV issues.

Preferred embodiments of the invention appear from the associated dependent claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described in detail in reference to the appended drawings, in which:

Fig. 1a-b are perspective views of the invention,

Fig. 2a-c show applications of the invention, and

Fig. 3a-b are sectional views of the invention, with the connector installed in line and with 3 degrees misalignment, respectively.

DETAILED DESCRIPTION OF THE INVENTION

A process piping system comprises typical pipes of different diameters connected together with stuff flanges and welded tees. Such a system will also have a branch line with a certain length offering enough flexibility for connection to neighbouring module piping system. This flexibility is offered by having long straight sections several bends to prevent overstressing the pipe. The angular misalignment between the connecting parts is the governing parameter producing stresses in the connecting pipes. With the described invention of multi-bore connector using a central hub connector accepting up to /-3 degrees in all directions, the flex loop can be significantly reduced. In addition to reduce branch pipe length, the reduced length will in most cases (combinations of flow velocity and density) increase the natural frequency above the threshold for FIV and make costly FIV measures redundant.

The multi-bore connector according to the invention is illustrated in Figure 1. It consists of two central hubs, a first hub 2A and a second hub 2B, two coupler rings 18A, 18B suspending several hydraulic coupler halves 5, and a 3- segment clamp 6 made up with a clamp locking bolt 7. The two central hubs 2A, 2B are designed to allow some misalignment there between, and are similar to the coupler disclosed in Norwegian patent no. 331285, which is owned by the present applicant.

The multi-bore connector may find several applications, as illustrated in Fig. 2a-c. In Fig. 2a the multi-bore connector 1 is freely suspended connecting two modules 8, 9. In Fig. 2b the coupler 1 is mounted vertically connecting a first module 8 with fixed piping and a second module 9 with flex loop piping. The secondary pipes are not shown in these examples, but are to be connected in the hydraulic couplers surrounding the central hub coupling. Fig. 2c is an example similar to Fig. 2b, here with the secondary piping 10 installed.

The multi-bore connector is shown in detail in Fig. 3a and 3b. The two hubs 2A, 2B are shown at a 0- and 3-degrees misalignment. The misalignment capability of /-3 degrees for the large bore pipe the production/injection pipe is considered enough since experiences have shown that the tolerance loop between modules will be less that these angles.

Specifically, the central connector includes a first hub 2A with an external thrust ring 11 with curved inner 12 and outer 13 surfaces and a second hub 2B adapted to contact the inner surface 12 of the male hub thrust ring 11. The inner surface12 of the thrust ring 11 and the mating outer surface14 of the female hub 2B should preferably be spherical. A sealing ring 15 is bridging an inner spherical surface 16 of the first hub 2A and an inner surface 17 of the second hub 2B. The inner surface 17 of the hub 2B may be conical.

The hubs 2A, 2B are held together by two coupler rings 18A, 18B engaging mating outer surfaces on the hubs, i.e. the outer surface 12 on the external thrust ring 11 on the first hub 2A and a corresponding outer surface 19 on the second hub 2B. All the four surfaces concerned should preferably be torus-shaped. The coupler rings 18A, 18B are mounted in a face-to-face configuration around the two central hubs 2A, 2B and include a number of hydraulic couplers 5 mounted in the circumference of the coupler rings.

Outside the coupler rings there is a locking clamp 6 with wedge-shaped (i. e. conical) inner surfaces engaging corresponding wedge-shaped outer surfaces on the coupler rings. In the illustrated embodiment (Fig. 1a), the locking clamp includes three parts that are hinged together. The clamp is closed by a clamp locking bolt 7. When the locking clamp is closed, the coupling rings 18A, 18B will be forced together in the axial direction and exert a pressure on the two hubs 2A, 2B locking the hubs together, even if the hubs are misaligned as shown in Fig. 3b. Any hydraulic pipes attached to the multi-bore connector will bend correspondingly.

The locking clamp may be realized in several forms. For example, including two part held together by two locking bolts, or two parts hinged together and closed by a single locking bolt. Presently, the three-part solution shown in Fig. 2 is the preferred embodiment.

The inventive multi-bore connector can be used for horizontal and vertical applications to reduce requirements for long flex loop to make up piping between modules. The shorter flex loop will in most cases (combinations of flow velocity and density) increase the natural frequency above the threshold frequency for the flex loop and thereby reduce the risk of flow induced vibration fatigue failures.

Claims

1. A multi-bore connector (1) including:

a first hub (2A) with an external thrust ring (11) with curved inner (12) and outer (13) surfaces,

a second hub (2B) adapted to contact the inner surface (12) of the thrust ring (11),

a sealing ring (15) in contact with an inner spherical surface (16) of the first hub (2A) and an inner surface (17) of the second hub (2B),

a locking clamp (6),

c h a r a c t e r i z e d i n a first coupler ring (18A) with a central opening for contacting the outer surface (13) of the thrust ring (11) of the first hub (2A),

a second coupler ring (18B) with a central opening for contacting an outer surface (19) of the second hub (2B), wherein the coupler rings (18A, 18B) are mounted face-to-face,

a number of hydraulic couplers (5) installed in the coupler rings (18A, 18B), and

wherein the locking clamp (6) is adapted to force the coupler rings (18A, 18B) together, whereupon the coupler rings (18A, 18B) will press against the hubs (2A, 2B) and lock the hubs together.

2. A multi-bore connector according to claim 1, wherein said outer surfaces of the hubs are torus-shaped contacting mating torus-shaped inner surfaces on said coupler rings.

3. A multi-bore connector according to claim 1 or 2, wherein the locking clamp includes wedge-shaped inner surfaces contacting mating wedge-shaped external surfaces on the coupler rings.

4. A multi-bore connector according to any of the claims 1 – 3, wherein the locking clamp includes a first part, a second part and two locking bolts.

5. A multi-bore connector according to any of the claims 1 – 3, wherein the locking clamp includes a first part hinged to a second part, and a locking bolt for closing the locking clamp.

6. A multi-bore connector according to any of the claims 1 – 3, wherein the locking clamp includes a first part hinged to a second part hinged to a third part, and a locking bolt for closing the locking clamp.