CA2333612A1 - Structural connection between swivels in swibel stack - Google Patents
Structural connection between swivels in swibel stack Download PDFInfo
- Publication number
- CA2333612A1 CA2333612A1 CA002333612A CA2333612A CA2333612A1 CA 2333612 A1 CA2333612 A1 CA 2333612A1 CA 002333612 A CA002333612 A CA 002333612A CA 2333612 A CA2333612 A CA 2333612A CA 2333612 A1 CA2333612 A1 CA 2333612A1
- Authority
- CA
- Canada
- Prior art keywords
- swivel
- turret
- box
- housing
- connector
- 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.)
- Abandoned
Links
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
- F16L13/00—Non-disconnectible pipe-joints, e.g. soldered, adhesive or caulked joints
- F16L13/14—Non-disconnectible pipe-joints, e.g. soldered, adhesive or caulked joints made by plastically deforming the material of the pipe, e.g. by flanging, rolling
- F16L13/147—Non-disconnectible pipe-joints, e.g. soldered, adhesive or caulked joints made by plastically deforming the material of the pipe, e.g. by flanging, rolling by radially expanding the inner part
Landscapes
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Joints Allowing Movement (AREA)
- Piles And Underground Anchors (AREA)
Abstract
A structural connection (3) between cylindrical housings of a swivel stack (10) is disclosed. A connector female half (6) is welded or machined to one end of a cylindrical housing of a product swivel (1). A pin male half (5) is welded or machined to an end of another product swivel (1) or a base member (2). An installation tool (7) pulls the pin (5) and box (6) together, radial ly expands the box (6), and then shrinks the box (6) onto the pin (5) so that n on- helical engaging threads (20) wedge together to produce axial tension in the connection (3). The connection (3) is structurally strong enough to act as a structural connection (3) between product swivels (1).
Description
TITLE: STRUCTURAL CONNECTION BETWEEN SWIVELS IN
SWIVEL STACK
BACKGROUND OF THE INVENTION
Cross Reference to Related Annlication This application claims priority from Provisional Application 60/090,482 filed 6/24/98.
Field of the Invention This invention relates in general to a stack of rotative couplings or swivels which are capable of transferring fluids between the sea bed and ships, tankers, and other sea-going vessels. In particular, the invention relates to structural connection arrangements for connecting swivels together in a stack.
Description of the Prior Art A swivel stack for a floating, production, storage and offloading (FPSO) vessel normally has a plurality of generally vertical product risers or pipes extending to the central body of the swivel stack from the sea floor. A swivel on the stack is normally provided for each fluid pipe which may be a manifold outlet pipe where several risers are applied to one manifold. Generally horizontal outlet pipes or conduits extend from the swivels to storage areas of the FPSO vessel. The vessel weathervanes about a turret to which the stack body and risers are connected, and the swivels move with the vessel relative to the swivel stack body and risers or manifold outlet pipes extending within the body. The stack body or core which receives the vertical risers is of a generally cylindrical shape. It is desirable to S minimize the dimensions of the stack body.
Hubs and bolted flanges have commonly been employed to connect the interior housing of one swivel in the stack to another interior housing below or to a base for the case of the lower-most swivel in the stack. Such hubs or flanges require space within the cylindrical body of the swivel stack.
A primary objective of the invention is to provide an effective structural connector for connecting interior housings of swivels together to form a swivel stack while minimizing the height of the connection between swivels thereby minimizing the total height of the swivel stack.
SUMMARY OF THE INVENTION
This invention is for a swivel stack comprising a plurality of rotative fluid couplings (called swivels) which are structurally connected together in a stack. The invention provides a structural connector between the top of an inner housing of one swivel and the bottom of an inner housing of a second swivel stacked on top of the first connector for each of the swivels in the stack. Such a structural connector also connects the bottom-most swivel to a cylindrical base which in turn is secured to the top of a turret in a turret mooring system. The preferred connector for connection of the swivels together in a swivel stack is a MERLIN TM
connector of Oil States Industries (UK) Ltd.
SWIVEL STACK
BACKGROUND OF THE INVENTION
Cross Reference to Related Annlication This application claims priority from Provisional Application 60/090,482 filed 6/24/98.
Field of the Invention This invention relates in general to a stack of rotative couplings or swivels which are capable of transferring fluids between the sea bed and ships, tankers, and other sea-going vessels. In particular, the invention relates to structural connection arrangements for connecting swivels together in a stack.
Description of the Prior Art A swivel stack for a floating, production, storage and offloading (FPSO) vessel normally has a plurality of generally vertical product risers or pipes extending to the central body of the swivel stack from the sea floor. A swivel on the stack is normally provided for each fluid pipe which may be a manifold outlet pipe where several risers are applied to one manifold. Generally horizontal outlet pipes or conduits extend from the swivels to storage areas of the FPSO vessel. The vessel weathervanes about a turret to which the stack body and risers are connected, and the swivels move with the vessel relative to the swivel stack body and risers or manifold outlet pipes extending within the body. The stack body or core which receives the vertical risers is of a generally cylindrical shape. It is desirable to S minimize the dimensions of the stack body.
Hubs and bolted flanges have commonly been employed to connect the interior housing of one swivel in the stack to another interior housing below or to a base for the case of the lower-most swivel in the stack. Such hubs or flanges require space within the cylindrical body of the swivel stack.
A primary objective of the invention is to provide an effective structural connector for connecting interior housings of swivels together to form a swivel stack while minimizing the height of the connection between swivels thereby minimizing the total height of the swivel stack.
SUMMARY OF THE INVENTION
This invention is for a swivel stack comprising a plurality of rotative fluid couplings (called swivels) which are structurally connected together in a stack. The invention provides a structural connector between the top of an inner housing of one swivel and the bottom of an inner housing of a second swivel stacked on top of the first connector for each of the swivels in the stack. Such a structural connector also connects the bottom-most swivel to a cylindrical base which in turn is secured to the top of a turret in a turret mooring system. The preferred connector for connection of the swivels together in a swivel stack is a MERLIN TM
connector of Oil States Industries (UK) Ltd.
The connector includes mating female (box) and male (pin) end portions welded to the cylindrical housing bottom of a top swivel and the cylindrical housing top of a bottom swivel. The mating female and male end portions have non-helical, interlocking circumferential teeth and are assembled with a hydraulic tool which is placed inside the connector male and female end portions. After stabbing of the male and female end portions of the swivels, hydraulic pressure is injected between the mating end portions thereby creating relative radial expansion between the male and female end portions, with equipment for pulling the two end portions into mating relationship. The hydraulic pressure is relieved and the box end shrinks about the pin end resulting in a wedging action of the teeth. The wedging action of the teeth converts radial preload into a high axial preload to maintain connector stiffness. The connector of this invention has advantages of (1) reduced size in outside diameter as well as height as compared to prior connection arrangements for swivels in a swivel stack, (2) a minimum number of connector parts (two) providing simplicity of design, and (3) significant time savings for make-up of each connection as compared to flanges or clamp style connections.
Other features and advantages of this invention will be apparent from the following specification and drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a schematic of a swivel stack showing a plurality of swivels connected together in a stack where each swivel is structurally connected to another swivel or to a cylindrical base with a MERLIN TM non-rotational connector; and WO 99/67563 PCTNS99/14218 ~
Other features and advantages of this invention will be apparent from the following specification and drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a schematic of a swivel stack showing a plurality of swivels connected together in a stack where each swivel is structurally connected to another swivel or to a cylindrical base with a MERLIN TM non-rotational connector; and WO 99/67563 PCTNS99/14218 ~
Figures 2A, 2B, and 2C illustrate steps for installing a MERLINrM type connector as a structural connector between swivel cylindrical housings or a swivel housing and a base.
DESCRIPTION OF THE INVENTION
Figure 1 shows a plurality of swivels stacked together to form a swivel stack 10. The inner housing of each swivel 1 is connected to the inner housing of a stacked swivel, or to the cylindrical housing of a base 2 by means of a connector pair 3 which is preferably a MERL,INTM connector available commercially from Oil States Industries (UK) Ltd. of Aberdeen, Scotland. Each connector pair includes a male (pin) connector half 5 and a female (box) half 6 which have non-helical, interlocking circumferential teeth and are assembled with a hydraulic tool 7 and other equipment for installing MERLINTM
connectors.
Figure 1 illustrates the assembly and the method for connecting the male 5 and female 6 parts of the connector pair 3 together. With the swivel base 2 in place, a lower-most swivel assembly 1 with the male portion 5 of the MERLINTM connector is lowered into the female portion 6 on top of the base 2. The swivel 1 is allowed to come to rest with the MERLINTM
connector halves engaged but not connected. Hoisting equipment is removed.
Next, the connector tool 7 is lowered into the swivel stack 10. Annular grooves 4 are provided in the interior of the swivel housings for engagement of the internal connector tool 7. Hydraulic pressure is injected between the teeth of the connector halves at 11 thereby creating radial elastic expansion between the male and female portions while allowing full axial insertion of the male portion into the female portion by connector tool 7. Hydraulic pressure is bled at 11 allowing the connector halves to radially contract or "shrink" elastically thereby providing radial wedging action of the teeth of the male and female portions. After the connection is made, the connection tool 7 is retrieved upwardly from inside the swivel, and the procedure is repeated to install successive swivels in the stack.
Figures 2A, 2B and 2C illustrate the steps in assembling female end portion 6 and male end portion 5. The connector pair 3 is not fully made up in this illustration of Figure 2A, but pin end 5 is stabbed into box end 6. The interlocking teeth 20 are non-helical interlocking teeth which, because of design geometry, can mesh only in the fully made-up position. Figure 2B shows the connection after a tool 7 is placed inside the connection with dogs 10 removably secured in grooves 4 of pin end 5 and box end 6. Hydraulic pressure is applied externally via port 11 for application of hydraulic pressure between the pin 5 and the box 6. The tool 7 pulls the pin 5 and box 6 together as illustrated by arrows A-A into a fully made-up relationship as the hydraulic pressure expands the box 6 and constricts the pin 5.
When pressure is released, the box 6 "shrinks" onto the pin 5. Figure 2C
illustrates the connection after the hydraulic tool 7 has been removed.
Structural connection of the inner housing swivels to form a swivel stack with a MERLIN~'M connector provides a structural connection that is simple and yet very strong. A
great advantage of the use of the MERLINTM connector is that it reduces the height of the connection between swivels as compared to prior flanged type connections.
Reduced height between each swivel translates into a reduced height of the entire swivel stack, resulting in a lower center of gravity of the swivel stack secured to the top of a turret in a turret mooring system of a vessel. A lower center of gravity reduces torque loads applied to the turret caused by rolling and other motions of the vessel. Lower torque loads on the turret results in less forces applied between the turret bearings and the vessel.
Another advantage in the connection of swivels together with a MERLINTM
connector is that an absolute minimum of parts are used: a female half is welded to the top of the swivel (or base) and a male half is welded to the bottom of the swivel.
Furthermore, significant time savings per connection are realized as compared to flange or clamp style connection of cylindrical members. Still another advantage is that the MERLINrM connector has an absolute minimum cross-section thereby reducing the weight of each connection to a minimum.
DESCRIPTION OF THE INVENTION
Figure 1 shows a plurality of swivels stacked together to form a swivel stack 10. The inner housing of each swivel 1 is connected to the inner housing of a stacked swivel, or to the cylindrical housing of a base 2 by means of a connector pair 3 which is preferably a MERL,INTM connector available commercially from Oil States Industries (UK) Ltd. of Aberdeen, Scotland. Each connector pair includes a male (pin) connector half 5 and a female (box) half 6 which have non-helical, interlocking circumferential teeth and are assembled with a hydraulic tool 7 and other equipment for installing MERLINTM
connectors.
Figure 1 illustrates the assembly and the method for connecting the male 5 and female 6 parts of the connector pair 3 together. With the swivel base 2 in place, a lower-most swivel assembly 1 with the male portion 5 of the MERLINTM connector is lowered into the female portion 6 on top of the base 2. The swivel 1 is allowed to come to rest with the MERLINTM
connector halves engaged but not connected. Hoisting equipment is removed.
Next, the connector tool 7 is lowered into the swivel stack 10. Annular grooves 4 are provided in the interior of the swivel housings for engagement of the internal connector tool 7. Hydraulic pressure is injected between the teeth of the connector halves at 11 thereby creating radial elastic expansion between the male and female portions while allowing full axial insertion of the male portion into the female portion by connector tool 7. Hydraulic pressure is bled at 11 allowing the connector halves to radially contract or "shrink" elastically thereby providing radial wedging action of the teeth of the male and female portions. After the connection is made, the connection tool 7 is retrieved upwardly from inside the swivel, and the procedure is repeated to install successive swivels in the stack.
Figures 2A, 2B and 2C illustrate the steps in assembling female end portion 6 and male end portion 5. The connector pair 3 is not fully made up in this illustration of Figure 2A, but pin end 5 is stabbed into box end 6. The interlocking teeth 20 are non-helical interlocking teeth which, because of design geometry, can mesh only in the fully made-up position. Figure 2B shows the connection after a tool 7 is placed inside the connection with dogs 10 removably secured in grooves 4 of pin end 5 and box end 6. Hydraulic pressure is applied externally via port 11 for application of hydraulic pressure between the pin 5 and the box 6. The tool 7 pulls the pin 5 and box 6 together as illustrated by arrows A-A into a fully made-up relationship as the hydraulic pressure expands the box 6 and constricts the pin 5.
When pressure is released, the box 6 "shrinks" onto the pin 5. Figure 2C
illustrates the connection after the hydraulic tool 7 has been removed.
Structural connection of the inner housing swivels to form a swivel stack with a MERLIN~'M connector provides a structural connection that is simple and yet very strong. A
great advantage of the use of the MERLINTM connector is that it reduces the height of the connection between swivels as compared to prior flanged type connections.
Reduced height between each swivel translates into a reduced height of the entire swivel stack, resulting in a lower center of gravity of the swivel stack secured to the top of a turret in a turret mooring system of a vessel. A lower center of gravity reduces torque loads applied to the turret caused by rolling and other motions of the vessel. Lower torque loads on the turret results in less forces applied between the turret bearings and the vessel.
Another advantage in the connection of swivels together with a MERLINTM
connector is that an absolute minimum of parts are used: a female half is welded to the top of the swivel (or base) and a male half is welded to the bottom of the swivel.
Furthermore, significant time savings per connection are realized as compared to flange or clamp style connection of cylindrical members. Still another advantage is that the MERLINrM connector has an absolute minimum cross-section thereby reducing the weight of each connection to a minimum.
Claims
SUBSTITUTE
5. As assembly for a floating storage and offloading vessel comprising:
a turret which is arranged and designed so that said vessel is capable of weathervaning about said turret when said turret is anchored to a seabed, at least one riser which extends to a hydrocarbon supply on the sea floor to a fluid flow swivel coupled to a top end of said turret, said swivel including a cylindrical internal housing (4), having a longitudinal axis and a rotatable swivel housing (1) which is rotatively coupled about the outer perimeter of said internal housing (4), with an internal flow path provided from said internal housing to said swivel housing and to said riser, said internal housing (4) being coupled to a cylindrical mounting base member (2) coupled to said turret, said cylindrical mounting base number (2) and said cylindrical internal housing (40 being secured together by a MERLIN type connector, said MERLIN type connector providing a structural connection between said internal housing (4) and said cylindrical mounting base member (2) coupled to said turret.
6. The assembly of claim 5 wherein said MERLIN type connector has mating box and pin end portions having non-helical, interlocking circumferential teeth which are arranged and designed to mesh only when fully made up and with said box end portion being shrunk onto said pin end portion, wherein said circumferential teeth are wedged together, thereby producing a high axial preload between said box and pin end portions that maintains stiffness and enhances fatigue characteristics of said connector.
7. As assembly for a floating storage and offloading vessel comprising:
a turret which is arranged and designed so that said vessel is capable of weathervaning about said turret when said turret is anchored to a seabed, at least two risers which extend to hydrocarbon supplies on the sea floor to at least two swivel members of a fluid swivel stack coupled to a top end of said turret, each one of said at least two swivels having a cylindrical internal housing having a longitudinal axis and a rotatable swivel housing which is rotatively coupled about the outer perimeter of said internal housing with an internal flow path provided form one of said two risers through said internal housing to said swivel housing.
8. The assembly of claim 7 wherein, said MERLIN type connector has mating box and pin end portions having non-helical, interlocking circumferential teeth which are arranged and designed to mesh only when fully made up and with said box end portion being shrunk onto said pin end portion, wherein said circumferential teeth are wedged together, thereby producing a high axial preload between said box and pin end portions that maintains stiffness and enhances fatigue characteristics of said connector.
5. As assembly for a floating storage and offloading vessel comprising:
a turret which is arranged and designed so that said vessel is capable of weathervaning about said turret when said turret is anchored to a seabed, at least one riser which extends to a hydrocarbon supply on the sea floor to a fluid flow swivel coupled to a top end of said turret, said swivel including a cylindrical internal housing (4), having a longitudinal axis and a rotatable swivel housing (1) which is rotatively coupled about the outer perimeter of said internal housing (4), with an internal flow path provided from said internal housing to said swivel housing and to said riser, said internal housing (4) being coupled to a cylindrical mounting base member (2) coupled to said turret, said cylindrical mounting base number (2) and said cylindrical internal housing (40 being secured together by a MERLIN type connector, said MERLIN type connector providing a structural connection between said internal housing (4) and said cylindrical mounting base member (2) coupled to said turret.
6. The assembly of claim 5 wherein said MERLIN type connector has mating box and pin end portions having non-helical, interlocking circumferential teeth which are arranged and designed to mesh only when fully made up and with said box end portion being shrunk onto said pin end portion, wherein said circumferential teeth are wedged together, thereby producing a high axial preload between said box and pin end portions that maintains stiffness and enhances fatigue characteristics of said connector.
7. As assembly for a floating storage and offloading vessel comprising:
a turret which is arranged and designed so that said vessel is capable of weathervaning about said turret when said turret is anchored to a seabed, at least two risers which extend to hydrocarbon supplies on the sea floor to at least two swivel members of a fluid swivel stack coupled to a top end of said turret, each one of said at least two swivels having a cylindrical internal housing having a longitudinal axis and a rotatable swivel housing which is rotatively coupled about the outer perimeter of said internal housing with an internal flow path provided form one of said two risers through said internal housing to said swivel housing.
8. The assembly of claim 7 wherein, said MERLIN type connector has mating box and pin end portions having non-helical, interlocking circumferential teeth which are arranged and designed to mesh only when fully made up and with said box end portion being shrunk onto said pin end portion, wherein said circumferential teeth are wedged together, thereby producing a high axial preload between said box and pin end portions that maintains stiffness and enhances fatigue characteristics of said connector.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US9048298P | 1998-06-24 | 1998-06-24 | |
| US60/090,482 | 1998-06-24 | ||
| PCT/US1999/014218 WO1999067563A1 (en) | 1998-06-24 | 1999-06-23 | Structural connection between swivels in swibel stack |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2333612A1 true CA2333612A1 (en) | 1999-12-29 |
Family
ID=22222966
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002333612A Abandoned CA2333612A1 (en) | 1998-06-24 | 1999-06-23 | Structural connection between swivels in swibel stack |
Country Status (4)
| Country | Link |
|---|---|
| AU (1) | AU4829499A (en) |
| BR (1) | BR9911847A (en) |
| CA (1) | CA2333612A1 (en) |
| WO (1) | WO1999067563A1 (en) |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NO170779C (en) * | 1983-04-05 | 1992-12-02 | Hunting Oilfield Equipment Hol | ROERSKJOET |
-
1999
- 1999-06-23 AU AU48294/99A patent/AU4829499A/en not_active Abandoned
- 1999-06-23 BR BR9911847-5A patent/BR9911847A/en unknown
- 1999-06-23 CA CA002333612A patent/CA2333612A1/en not_active Abandoned
- 1999-06-23 WO PCT/US1999/014218 patent/WO1999067563A1/en active Application Filing
Also Published As
| Publication number | Publication date |
|---|---|
| AU4829499A (en) | 2000-01-10 |
| BR9911847A (en) | 2001-03-20 |
| WO1999067563A1 (en) | 1999-12-29 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDE | Discontinued |