A tensioner for providing a conduit, e.g., drilling and production riser strings, from a floating vessel at the surface of the ocean to the blowout preventer stack, production tree, or other assembly which is connected to the wellhead at the sea floor. The tensioner compensates for vessel motion induced by wave action and heave and maintains a variable tension to the riser string alleviating the potential for compression and thus buckling or failure of the riser string. The tensioner of the present invention preferably includes at least one mandrel having at least one hang-off donut; at least one upper flexjoint swivel assembly, at least one radially ported manifold, and at least one tensioning cylinder co-linearly combined in a single unit. Methods for assembling risers are also disclosed.

1. Field of the Invention
The invention relates to offshore drilling and production operations and is specifically directed to drilling and production tensioners and risers assembled using the tensioners.
2. Description of Related Art
A marine riser system is employed to provide a conduit from a floating vessel at the water surface to the blowout preventer stack or, production tree, which is connected to the wellhead at the sea floor. A tensioning system is utilized to maintain a variable tension to the riser string alleviating the potential for compression and in turn buckling or failure.
Historically, conventional riser tensioner systems have consisted of both single and dual cylinder assemblies with a fixed cable sheave at one end of the cylinder and a movable cable sheave attached to the rod end of the cylinder. The assembly is then mounted in a position on the vessel to allow convenient routing of wire rope which is connected to a point at the fixed end and strung over the movable sheaves. A hydro/pneumatic system consisting of high pressure air over hydraulic fluid applied to the cylinder forces the rod and in turn the rod end sheave to stroke out thereby tensioning the wire rope and in turn the riser.
The number of tensioner units employed is based on the tension necessary to maintain support of the riser and a percentage of overpull which is dictated by met-ocean conditions i.e., current and operational parameters including variable mud weight, etc.
Normal operation of these conventional type tensioning systems have required high maintenance due to the constant motion producing wear and degradation of the wire rope members. Replacing the active working sections of the wire rope by slipping and cutting raises safety concerns for personnel and has not proven cost effective. In addition, available space for installation and, the structure necessary to support the units including weight and loads imposed, particularly in deep water applications where the tension necessary requires additional tensioners poses difficult problems for system configurations for both new vessel designs and upgrading existing vessel designs.
Recent deepwater development commitments have created a need for new generation drilling vessels and production facilities requiring a plethora of new technologies and systems to operate effectively in deep water and alien/harsh environments. These new technologies include riser tensioner development where direct acting cylinders are utilized.
Current systems as manufactured by Hydralift employ individual cylinders arranged to connect one end to the underside of the vessel sub-structure and one end to the riser string. These direct acting cylinders are equipped with ball joint assemblies in both the rod end and cylinder end to compensate for riser angle and vessel offset. Although this arrangement is an improvement over conventional wire rope systems, there are both operational and configuration problems associated with the application and vessel interface. For example, one problem is the occurrence of rod and seal failure due to the bending induced by unequal and non-linear loading caused by vessel roll and pitch. Additionally, these systems cannot slide off of the wellbore centerline to allow access to the well. For example, the crew on the oil drilling vessel is not able to access equipment on the seabed floor without having to remove and breakdown the riser string.
The tensioner system of the present invention is an improvement over existing conventional and direct acting tensioning systems. Beyond the normal operational application to provide a means to apply variable tension to the riser, the system provides a number of enhancements and options including vessel configuration and its operational criteria.
The tensioner system has a direct and positive impact on vessel application and operating parameters by extending the depth of the water in which the system may be used and operational capability. In particular, the system is adaptable to existing medium class vessels considered for upgrade by reducing the structure, space, top side weight and complexity in wire rope routing and maintenance, while at the same time increasing the number of operations which can be performed by a given vessel equipped with the tensioner system.
Additionally, the present invention extends operational capabilities to deeper waters than conventional tensioners by permitting increased tension while reducing the size and height of the vessel structure, reducing the amount of deck space required for the tensioner system, reducing the top-side weight, and increasing the oil drilling vessel""s stability by lowering its center of gravity.
Moreover, the tensioner of the present invention is co-linearly symmetrical with tensioning cylinders. Therefore, the present tensioner eliminates offset and the resulting unequal loading that causes rapid rod and seal failure in some previous systems.
The tensioner of the present invention is also radially arranged and may be affixed to the vessel at a single point. Therefore, the tensioner may be conveniently installed or removed as a single unit through a rotary table opening, or disconnected and moved horizontally while still under the vessel.
The tensioner of the present invention further offers operational advantages over conventional methodologies by providing options in riser management and current well construction techniques. Applications of the basic module design are not limited to drilling risers and floating drilling vessels. The system further provides cost and operational effective solutions in well servicing/workover, intervention and production riser applications. These applications include all floating production facilities including, tension leg platform (T.L.P.) floating production facility (F.P.F.) and production spar variants. The system when installed provides an effective solution to tensioning requirements and operating parameters including improving safety by eliminating the need for personnel to slip and cut tensioner wires with the riser suspended in the vessel moonpool. An integral control and data acquisition system provides operating parameters to a central processor system which provides supervisory control.
The present invention is also directed to a method of assembling a string of production riser, or production riser, for drill stem testing while the larger string of drilling riser, referred to herein as the drilling riser, is still suspended from the vessel, and preferably, still connected to the wellhead. Therefore, the amount of time, and thus money, required to prepare for the drill stem test is substantially reduced. While the background of method of assembling a production riser will be discussed in greater detail, it is to be understood that the methods of the present invention include assembling a drilling riser.
Generally, a well is first drilled from a drilling vessel or drilling platform having one or more derricks for supporting the drilling riser and other drilling equipment. After drilling is completed, the well is xe2x80x9cclosed offxe2x80x9d using valves or other equipment. The drilling riser is then disassembled. The production riser is then assembled, usually utilizing the same derrick and equipment. This is especially true in vessels having only one fill size derrick that can support the weight of the riser. Both the drilling riser and the production riser consist of tubulars, e.g., casing, attached end to end and extended from the wellhead to the drilling or production facility, e.g., vessel or platform.
Alternatively, in drilling vessels having two derricks, the second derrick may be utilized to assemble the production riser. After the production riser is assembled, it is attached to the wellhead and a drill stem test is performed. The drill stem test is an evaluation of unrestricted flow of hydrocarbon, e.g., oil or gas, from the well and into shipboard tanks to facilitate determining the hydrocarbon reservoir""s size and propensity to flow, e.g., the pressure differential between the well and the tanks capturing the flowing hydrocarbon.
Present methods and applications of this process require either two derricks on the drilling or production vessel or platform, or, require substantially amounts of time, and thus money, to detach and disassemble the drilling riser from the wellhead, and then assemble and attach the production riser to the wellhead using a single derrick.
The methods of the present invention overcome this problem because a derrick is not required to assemble the riser. Instead, a crane,jack knife hoisting rig, or other lifting device smaller than a full size derrick may be used. Additionally, the methods of the present invention provide the advantages of: providing a means to run the riser from the unused rig floor aboard a drilling or production facility, without the use of a standard capacity derrick; includes a system that is modular in construction, transportation, and assembly; providing interchangeability with other drilling or production facilities; permitting assembly of the production riser while the drilling riser is still in use and vice versa; reducing the amount of time that the wellhead is xe2x80x9cidle,xe2x80x9d i.e., that either a drilling riser or production riser is in use; reducing the amount of extra equipment that is needed by the facility in making the rig floor ready for use; providing sufficient tension to the long string of the riser in deepwater over extended periods of time; providing a means to maintain the riser in constant tension, with, if necessary, overpull, while the riser is in service; providing the capability to accommodate angular offset between the riser and the vessel induced by vessel motion; and providing the capability to accommodate axial torque induced in the riser string in the event the drilling or production vessel rotates around the wellhead due to weather and sea conditions.
Further, the methods of assembling a riser using the tensioner of the present invention permit the assembly of the production riser without having to disconnect, or disassemble the drilling riser from the wellhead, and vice versa. Therefore, the drilling tubulars and riser can subsequently be disconnected from the wellhead and the vessel moved to position the pre-assembled production riser into to place and secured to the wellhead, and vice versa, thereby resulting in time, and thus, cost savings.
The foregoing advantages have been obtained through the present tensioner comprising: at least one mandrel; at least one upper flexjoint swivel assembly in communication with the at least one mandrel; at least one manifold in communication with the at least one upper flexjoint swivel assembly, the at least one manifold having a first radial fluid band and a second radial fluid band; at least one tensioning cylinder having a blind end, a rod end, and at least one transfer tubing, the blind end being in communication with the first radial fluid band, the transfer tubing being in communication with the second radial fluid band and the rod end being in communication with at least one flexjoint bearing; and a base in communication with the at least one flexjoint bearing.
A further feature of the tensioner is that the manifold may include a third radial fluid band, the third radial fluid band being in communication with either the blind end or the at least one transfer tubing. Another feature of the tensioner is that the first and third radial fluid bands may be in communication with the at least one transfer tubing and the second radial fluid band may be in communication with the blind end of the at least one tensioning cylinder. An additional feature of the tensioner is that the tensioner may include six tensioning cylinders, wherein at least one tensioning cylinder may be in communication with a first control source and at least one tensioning cylinder may be in communication with a second control source. Still another feature of the tensioner is that the first control source and second control source may be in communication with the same tensioning cylinder. A further feature of the tensioner is that the tensioner may include a hang-off donut. Another feature of the tensioner is that the hang-off donut may be disposed on the mandrel or along the tensioning cylinders, e.g., below the blind end of the tensioning cylinders which captures each of the tensioning cylinders and allows for the transference of axial tension load from the cylinder casing to the mandrel and then directly to the rig structure. An additional feature of the tensioner is that the blind end may be connected to the manifold by at least one sub seal. Still another feature of the tensioner is that each of the at least one tensioning cylinder may include at least one cylinder head. Yet another feature of the tensioner is that the first, second, and third radial fluid bands may each be in communication with a transducer. A further feature of the tensioner is that the tensioner may include at least two tensioning cylinders. Another feature of the tensioner is that the tensioner may include two radial fluid bands in communication with at least one transfer tubing and one radial fluid band in communication with the blind end of each of the at least one tensioning cylinder. An additional feature of the tensioner is that a sub-manifold may be included between the blind end of the tensioning cylinder and the manifold, thereby permitting remotely operated valves to be disposed in the communication channels between the tensioning cylinders and the manifold making it possible to isolate any single or combination of tensioning cylinders for operation, maintenance and Riser Disconnect Management Systems (RDMS) procedures. Still another feature of the tensioner is that a swivel feature may be incorporated either within or in the area of the manifold or upper flexjoint swivel assembly, thereby providing a means to remotely turn the entire tensioner to remove torsional stresses in the riser string that result from the vessel changing heading. A further feature of the tensioner is that the tensioner may further comprise at least one lower flexjoint swivel assembly in communication with the at least one tensioning cylinder and the base.
The foregoing advantages have also been achieved through the present tensioner comprising: at least one mandrel having a first mandrel end and a second mandrel end; at least one upper flexjoint swivel assembly having a first upper flexjoint swivel assembly end and a second upper flexjoint swivel assembly end; at least one manifold having a first manifold surface and a second manifold surface; at least one tensioning cylinder having a blind end, a rod end, and at least one flexjoint bearing in communication with the rod end; and a base, wherein the second mandrel end is connected to the first upper flexjoint swivel assembly end, the second upper flexjoint swivel assembly end is connected to the first manifold surface, the second manifold surface is connected to the blind end, and the rod end and the at least one flexjoint bearing are connected to the base.
A further feature of the tensioner is that tensioner may further include at least one lower flexjoint swivel assembly having a first lower flexjoint swivel assembly end and a second lower flexjoint swivel assembly end, wherein the rod end is connected to the first lower flexjoint swivel assembly end and the second lower flexjoint swivel assembly end is connected to the base. A further feature of the tensioner is that the at least one tensioning cylinder may include at least one transfer tubing, the at least one transfer tubing being in communication with the manifold. Another feature of the tensioner is that the manifold may include two radial fluid bands in communication with the at least one transfer tubing and one radial fluid band in communication with the blind end of the at least one tensioning cylinder. An additional feature of the tensioner is that the tensioner may include six tensioning cylinders, wherein at least one of the tensioning cylinders is in communication with a first control source and at least one tensioning cylinder is in communication with a second control source. Still another feature of the tensioner is that the first control source and the second control source may be in communication with the same tensioning cylinder. A further feature of the tensioner is that the tensioner may include a hang-off donut. Another feature of the tensioner is that the at least one manifold may include at least two radial fluid bands. An additional feature of the tensioner is that at least one of the at least two radial fluid bands may be in communication with the blind end and at least one of the at least two radial fluid bands may be in communication with the rod end.
The foregoing advantages have also been achieved through the present tensioner comprising: at least one mandrel, at least one upper flexjoint swivel assembly, at least one manifold, at least one tensioning cylinder, and a base, the at least one tensioning cylinder includes a blind end in communication with the at least one manifold and a rod end in communication with the base; wherein the at least one mandrel, the at least one upper flexjoint swivel assembly, the at least one manifold, the at least one tensioning cylinder, and the base are assembled to form a unitary, co-linear tensioner.
A further feature of the tensioner is that the tensioner may further comprise at least one lower flexjoint swivel assembly. An additional feature of the tensioner is that the at least one mandrel may be connected to the at least one upper flexjoint swivel assembly, the at least one upper flexjoint swivel assembly being connected to the at least one manifold, the at least one manifold being connected to the at least one tensioning cylinder, the at least one tensioning cylinder being connected to the at least one lower flexjoint swivel assembly, and the at least one lower flexjoint swivel assembly being connected to the base.
The foregoing advantages have also been achieved through the present method for assembling a riser having a plurality of tubulars comprising the steps of: (a) providing a tensioner having a first tensioner end, a second tensioner end, a retracted position, an extended position, at least one mandrel, at least one upper flexjoint swivel assembly in communication with the at least one mandrel, at least one manifold in communication with the at least one upper flexjoint swivel assembly, the at least one manifold having a first radial fluid band and a second radial fluid band, at least one tensioning cylinder having a blind end, a rod end, and at least one transfer tubing, the blind end being in communication with the first radial fluid band, the transfer tubing being in communication with the second radial fluid band, and a base in communication with the rod end of each of the at least one tensioning cylinder; (b) providing a drilling or production facility having a rig floor and a moonpool disposed below the rig floor, the rig floor including at least one rig floor slip having a rig floor slip opened position and a rig floor slip closed position; (c) inserting the tensioner through the at least one rig floor slip, through the rig floor, and into the moonpool; (d) connecting the tensioner to the rig floor; (e) inserting a first tubular through the at least one rig floor slip, through the rig floor, through the tensioner, and into the moonpool; (f) disposing the at least one rig floor slip around the first tubular and moving the at least one rig floor slip from the rig floor slip opened position to the rig floor slip closed position, whereby the first tubular is maintained in place by the at least one rig floor slip; (g) connecting a second tubular to the first tubular thereby forming a riser having a plurality of tubulars; (h) moving the at least one rig floor slip from the rig floor closed position to the rig floor opened position; (i) inserting the second tubular through the at least one rig floor slip, through the rig floor, through the tensioner, and into the moonpool; (j) moving the at least one rig floor slip from the rig floor slip opened position to the rig floor slip closed position, whereby the riser is maintained in place by the at least one rig floor slip; (k) releasably securing the base of the tensioner to the first tubular; (l) connecting a third tubular to the second tubular; (m) moving the at least one rig floor slip from the rig floor closed position to the rig floor opened position; (n) inserting the third tubular through the at least one rig floor slip, through the rig floor, through the tensioner, and into the moonpool, thereby moving the tensioner from the retracted position to the extended position; (o) moving the at least one rig floor slip from the rig floor slip opened position to the rig floor slip closed position; (p) releasing the base of the tensioner from the first tubular, whereby the riser is maintained in place by the at least one rig floor slip; (q) moving the tensioner from the extended position to the retracted position; (r) releasably securing the base of the tensioner to the second tubular; (s) connecting a fourth tubular to the third tubular; (t) moving the at least one rig floor slip from the rig floor closed position to the rig floor opened position; (u) inserting the fourth tubular through the at least one rig floor slip, through the rig floor, through the tensioner, and into the moonpool, thereby moving the tensioner from the retracted position to the extended position; (v) moving the at least one rig floor slip from the rig floor slip opened position to the rig floor slip closed position; (w) releasing the base of the tensioner from the second tubular, whereby the riser is maintained in place by the at least one rig floor slip; (x) moving the tensioner from the extended position to the retracted position; and (y) releasably securing the base of the tensioner to the third tubular.
A further feature of the method for assembling a riser having a plurality of tubulars is that steps (s) through (y) may be repeated with at least one additional tubular until the riser has a predetermined length. Another feature of the method for assembling a riser having a plurality of tubulars is that the method may further include the steps of: connecting a final tubular to the riser; and inserting the final tubular through the at least one rig floor slip, through the rig floor and the tensioner, and into the moonpool. An additional feature of the method for assembling a riser having a plurality of tubulars is that the tensioner may be moved from the extended position to the retracted position, by activating at least one control source in communication with the tensioner. Still another feature of the method for assembling a riser having a plurality of tubulars is that the tensioner and each of the plurality of tubulars may be inserted through the rig floor and into the moonpool by lifting and positioning the tensioner and each of the plurality of tubulars with a crane. A further feature of the method for assembling a riser having a plurality of tubulars is that the tensioner and each of the plurality of tubulars may be inserted through the rig floor and into the moonpool by lifting and positioning the tensioner and each of the plurality of tubulars with a jack knife hoisting rig. Another feature of the method for assembling a riser having a plurality of tubulars is that the tensioner may be connected to the rig floor by removing the at least one rig floor slip and resting the tensioner on the rig floor. An additional feature of the method for assembling a riser having a plurality of tubulars is that the tensioner may be connected to the rig floor by placing the tensioner in communication with a rotating bearing disposed on the rig floor. Still another feature of the method for assembling a riser having a plurality of tubulars is that at least one spider beam may be inserted and at least one subsea appliance is disposed on the at least one spider beam and connected to the first tubular prior to the connection of the second tubular to the first tubular. A further feature of the method for assembling a riser having a plurality of tubulars is that the at least one spider beam may be removed after the connection of the at least one subsea appliance is connected to the first tubular.
The foregoing advantages have also be achieved through the present method for assembling a riser having a plurality of tubulars comprising the steps of: (a) providing a tensioner having a first tensioner end, a second tensioner end, a retracted position, an extended position, at least one mandrel, at least one upper flexjoint swivel assembly in communication with the at least one mandrel, at least one manifold in communication with the at least one upper flexjoint swivel assembly, the at least one manifold having a first radial fluid band and a second radial fluid band, at least one tensioning cylinder having a blind end, a rod end, and at least one transfer tubing, the blind end being in communication with the first radial fluid band, the transfer tubing being in communication with the second radial fluid band, and a base in communication with the rod end of each of the at least one tensioning cylinder; (b) providing a drilling or production facility having a rig floor and a moonpool disposed below the rig floor, the rig floor having at least one rig floor slip having a rig floor slip opened position and a rig floor slip closed position; (c) inserting a first tubular through the at least one rig floor slip, through the rig floor, and into the moonpool; (d) moving the at least one rig floor slip from the rig floor slip opened position to the rig floor slip closed position, whereby the first tubular is maintained in place by the at least one rig floor slip; (e) connecting a second tubular to the first tubular thereby forming a riser having a plurality of tubulars; (f) moving the at least one rig floor slip from the rig floor closed position to the rig floor opened position; (g) inserting the second tubular through the at least one rig floor slip, through the rig floor, and into the moonpool; (h) moving the at least one rig floor slip from the rig floor slip opened position to the rig floor slip closed position, whereby the riser is maintained in place by the at least one rig floor slip; (i) providing at least one spider beam, the at least one spider beam having at least one spider beam slip having a spider beam slip opened position and a spider beam slip closed position; (j) disposing the at least one spider beam slip around the riser and moving the at least one spider beam slip from the spider beam slip opened position to the spider beam slip closed position; (k) moving the at least one rig floor slip from the rig floor slip closed position to the rig floor slip opened position, whereby the riser is maintained in place by the at least one spider beam slip; (l) lowering the tensioner over the riser, through the rig floor, and into the moonpool, whereby the riser passes through the tensioner; (m) connecting the tensioner to the rig floor; (n) releasably securing the base of the tensioner to the riser; and (o) moving the at least one spider beam slip from the spider beam slip opened position to the spider beam slip closed position, whereby the riser is maintained in place by the tensioner.
A further feature of the method for assembling a riser having a plurality of tubulars is that after step (h), steps (e) through (h) may be repeated with at least one additional tubular until the production riser has a predetermined length. Another feature of the method for assembling a riser having a plurality of tubulars is that the riser may include at least 10 tubulars. An additional feature of the method for assembling a riser having a plurality of tubulars is that the riser may include at least 50 tubulars. Still another feature of the method for assembling a riser having a plurality of tubulars is that the tensioner and each of the plurality of tubulars may be inserted through the rig floor and into the moonpool by lifting and positioning the tensioner and each of the plurality of tubulars with a crane. A further feature of the method for assembling a riser having a plurality of tubulars is that the tensioner and each of the plurality of tubulars may be inserted through the rig floor and into the moonpool by lifting and positioning the tensioner and each of the plurality of tubulars with a jack knife hoisting rig. Another feature of the method for assembling a riser having a plurality of tubulars is that step (e) may be achieved by: hoisting and positioning the second tubular above the first tubular and connecting the second tubular to the first tubular. An additional feature of the method for assembling a riser having a plurality of tubulars is that the tensioner may be connected to the rig floor by moving the at least one rig floor slip from the rig floor slip opened position to the rig floor slip closed position. Still another feature of the method for assembling a riser having a plurality of tubulars is that the tensioner may be connected to the rig floor by resting the tensioner on the rig floor. A further feature of the method for assembling a riser having a plurality of tubulars is that the tensioner may be connected to the rig floor by placing the tensioner in communication with a rotating bearing disposed on the rig floor.
The foregoing advantages have also been achieved through the present method for assembling a riser having a plurality of tubulars comprising the steps of: (a) providing a tensioner having a first tensioner end, a second tensioner end, a retracted position, an extended position, at least one mandrel, at least one upper flexjoint swivel assembly in communication with the at least one mandrel, at least one manifold in communication with the at least one upper flexjoint swivel assembly, the at least one manifold having a first radial fluid band and a second radial fluid band, at least one tensioning cylinder having a blind end, a rod end, and at least one transfer tubing, the blind end being in communication with the first radial fluid band, the transfer tubing being in communication with the second radial fluid band, and a base in communication with the rod end of each of the at least one tensioning cylinder; (b) providing a drilling or production facility having a rig floor and a moonpool disposed below the rig floor, the rig floor having at least one rig floor slip having a rig floor slip opened position and a rig floor slip closed position; (c) inserting a first tubular through the at least one rig floor slip, through the rig floor, and into the moonpool; (d) moving the at least one rig floor slip from the rig floor slip opened position to the rig floor slip closed position, whereby the first tubular is maintained in place by the at least one rig floor slip; (e) providing at least one spider beam, the at least one spider beam having at least one spider beam slip having a spider beam slip opened position and a spider beam slip closed position; (f) disposing the at least one spider beam slip around the first tubular and moving the at least one spider beam slip from the spider beam slip opened position to the spider beam slip closed position; (g) moving the at least one rig floor slip from the rig floor slip closed position to the rig floor slip opened position, whereby the first tubular is maintained in place by the at least one spider beam slip; (h) lowering the tensioner over the first tubular, through the rig floor, and into the moonpool, whereby the first tubular passes through the tensioner; (i) connecting the tensioner to the rig floor; (j) releasably securing the base of the tensioner to the first tubular; (k) moving the at least one spider beam slip from the spider beam slip closed position to the spider beam slip opened position, whereby the first tubular is maintained in place by the tensioner; (l) connecting a second tubular to the first tubular thereby forming a riser having a plurality of tubulars; (m) moving the at least one rig floor slip from the rig floor closed position to the rig floor opened position; (n) inserting the second tubular through the at least one rig floor slip, through the rig floor, through the tensioner, and into the moonpool, thereby moving the tensioner from the retracted position to the extended position; (o) moving the at least one rig floor slip from the rig floor slip opened position to the rig floor slip closed position; (p) releasing the base of the tensioner from the riser, whereby the riser is maintained in place by the at least one rig floor slip; (q) moving the tensioner from the extended position to the retracted position; and (r) releasably securing the base of the tensioner to the riser.
A further feature of the method for assembling a riser having a plurality of tubulars is that the method further includes the step of: (s) repeating steps (l) through (r) with at least one additional tubular until the riser has a predetermined length. Another feature of the method for assembling a riser having a plurality of tubulars is that the second tubular may be connected to the first tubular to form the riser having a plurality of tubulars prior to step (h). An additional feature of the method for assembling a riser having a plurality of tubulars is that at least two additional tubulars may be connected to the riser prior to step (h) by: moving the at least one rig floor slip from the rig floor closed position to the rig floor opened position; connecting the at least one additional tubular to the riser; inserting the at least one additional tubular through the at least one rig floor slip, through the rig floor, and into the moonpool; moving the at least one rig floor slip from the rig floor slip opened position to the rig floor slip closed position, whereby the riser is maintained in place by the at least one rig floor slip; repeating the above steps with at least one additional tubular until the production riser has a predetermined length. Still another feature of the method for assembling a riser having a plurality of tubulars is that the method may further comprise the step of: removing the at least one spider beam after step (k). A further feature of the method for assembling a riser having a plurality of tubulars is that the method may further comprise the steps of: connecting a final tubular to the production riser; and inserting the final tubular through the at least one rig floor slip, through the rig floor, and into the moonpool.

Co-linear tensioner and methods for assembling production and drilling risers using same


Automated email categorization and rule creation for email management is provided. An automated filing engine parses an email message for identifying key terms and contextual information for categorizing the email message. Criteria are determined for associating email messages with a particular category. Upon reaching a predetermined threshold, a notification is provided to the email message recipient user, enabling the user to select to allow the automated filing engine to generate a new email folder associated with the category, and to move emails meeting the criteria to the new email folder. The automated filing engine creates a rule based on the criteria, and applies the rule to received email messages, such that email messages meeting the criteria are automatically filed.

An electronic mail application is a useful communication tool. However, many users feel overwhelmed by the amount of email messages that they receive and the need to act on received messages. Oftentimes, as the number of email messages a user receives increases, the user's ability to efficiently organize messages becomes progressively more challenging. Some users may accumulate email messages in an inbox folder, and must scour through their entire inboxes to find a particular email item. As can be appreciated, this can be inefficient and time-consuming. Some users set up a filing system to manage their email messages. For example, a user may set up folders that may relate to broad categories or to particular projects. When an email message arrives in a user's inbox, the user may manually file the message in an appropriate folder. Other users may establish rules that sort email messages into particular folders as they come in. Currently, email organization requires manual work on behalf of the user (e.g., filing emails, creating rules), which does not allow for a maximization of user productivity and efficiency.


Provided is a medical device for clearing an obstruction from a surgical instrument or surgical site, the device comprising: a first hollow member configured to allow air or inert gas passage; a second hollow member having a distal end and a proximal end, the proximal end configured to be connectable to a vacuum or suction source; a housing member configured to receive both the first hollow member and the second hollow member; and a push button operably connected to the housing member; and an inflation bulb configured to be attachable to the housing member, wherein the push button is configured to disengage the first hollow member and occlude the second hollow member when depressed by a force, and/or wherein the push button and the inflation bulb are configured to be operable by one hand of an operator.

Surgical instruments used to shave, cut, resect, abrade and/or remove tissue, bone and or other bodily materials are known. Once the tissue, bone and/or any other bodily materials are cut, it is necessary to remove them from the surgical site. This is typically accomplished through an inner lumen provided in the surgical instrument that is connected to a suction source. Existing surgical instrument may utilize a one-way suction line to aspirate tissue from the surgical site. It is often the case that the tissue forms a clog in the aspiration pathway (most often in the distal end of the surgical instrument). One way to remove the clog is for the person using the surgical instrument to remove the instrument from the surgical site and insert a stylet into the cutting window to force the clog through the cutting portion and into the inner lumen to be aspirated. However, this is often a time-consuming and tedious process, particularly over the course of a surgical procedure in which the surgeon may have to remove multiple clogs. Furthermore, removing and reinserting the surgical instrument is traumatic to the surgical site.
Cleaning functions such as irrigation, suction, or both may also be provided to or incorporated with a surgical instrument during a procedure in order to maintain the surgical instrument clean, which typically requires connecting various individual cables, tubes, lines, ports, etc. to the instrument. The various individual cables, tubes, lines, ports, etc. connected to the surgical instrument may however interfere with a doctor or surgeon performing the medical procedure, which may undesirably add additional time and/or complications to the procedure. Also, by connecting various individual cables, tubes, lines, ports, etc. to the surgical instrument, selective application of irrigation fluid, suction, or both may be difficult to control.
Therefore, in view of the above-mentioned problems associated with clearing clogs from a surgical instrument, it is desirable to develop ways of clearing clogs quickly and efficiently during a surgical procedure.


A double-wound center-feed roll is disclosed which is formed from at least two webs each having lines of weakness which allow the webs to be separated into a plurality of sheets. The lines of weakness of one web are offset from those of the other such that in use the sheets can be dispensed singly from alternate webs. A first portion of the webs at the center of the roll is lightly bonded together while a second portion of the webs on the outside of the roll remains unbonded. The center-feed roll of the present invention reduces the occurrence of both web orientation reversal and streaming dispensing problems.

Center-feed rolls that consist of webs of paper, nonwoven, or other sheet-like materials which are perforated such that the webs can be separated into individual sheets are well-known to those skilled in the art. The roll is often installed in a dispenser with the axis of the roll being vertical, and the sheet-like material is fed from the center of the roll out of the dispenser through an aperture, usually in the base of the dispenser. This type of roll and dispenser is often found in public restrooms, gas station pump areas, and in hospitals and industry, either for use as a dispenser for hand towels or for tissues or towels for general cleaning use.
EP-0865247-B1 to King discloses a double-wound center-feed roll and a dispenser for supporting the roll having an aperture and a base in the dispenser which is provided with a rim which projects into the center of the roll in use. It describes a center-feed roll formed from two webs each having lines of weakness which allow the webs to be separated into a plurality of individual sheets. The lines of weakness of one web are offset from those of the other such that in use the sheets can be dispensed singly from alternate webs. Thus, it provides a double-wound center-feed roll which allows single-sheet dispensing. In use, both webs feed through the aperture of the dispenser, with one web protruding further than the other due to the offset lines of weakness. A user grips and pulls the outermost web, and the friction between it and the aperture causes the next line of weakness in that web to break when it is at or near the aperture such that a single sheet is dispensed. As one web is being pulled from the dispenser and a sheet detached, the other web is also being drawn out from the dispenser. Because the lines of weakness are offset, when the line of weakness of one web breaks, the first sheet of the next web is already protruding from the dispenser. Thus, a well-presented and untouched sheet is available for the next user.
Dispensing performance of the above-described double-wound center-feed roll can be impaired if the orientation of the dispensing webs is reversed. Double-wound center feed rolls are made, as described above, with an inner web and an outer web. The inner web is positioned directly adjacent to the core or the center of the roll. The outer web is separated from the core or center of the roll by the inner web. Web orientation reversal occurs when one complete circumference of the inner web is removed without removing any portion of the outer web. When this occurs, the inner web becomes the outer web and the outer web becomes the inner web.
Web orientation reversal impairs dispensing performance because it can change the relationship of the offset perforations between the inner and the outer webs. When the inner web and the outer web are maintained in the proper relationship, i.e., the inner web remains the inner web and the outer web remains the outer web, the perforations in the inner and outer webs are offset. If the webs reverse, the perforations of the new inner and new outer webs may not have the proper spacing with respect to one another and dispensing may become more difficult or stop altogether.
One method of reducing the incidence of web orientation reversal is to lightly crimp the inner web to the outer web prior to winding the inner and outer web into a roll. Processes for lightly crimping layers together are known in the art. Lightly crimping the inner and outer layers associates the layers together making it less likely for a user to reverse the two layers. However, the light crimping increases the dispensing force required to separate one web from the other and is likely to increase the incidence of streaming, a dispensing problem that occurs when an individual sheet fails to separate, but rather, continues to pull an excessively long section of attached sheets from the dispenser.
Therefore, there is a need for a double-wound center-feed roll in which single sheets can be dispensed with both reduced opportunity for reversal of the inner and outer webs and reduced incidence of streaming. Additionally, there is a need for a process for manufacturing the same.

Center-feed roll and method of making thereof


A repeater system for extending cell coverage, including a frequency band translation repeater for transmitting radio frequency (RF) signals to and receiving RF signals from a base station and translating between the frequency band of THE RF signals and a different frequency band for RF transmission directly between the repeater and user equipment.

The base stations of public land mobile telecommunications networks each have a radio range determined by the characteristics of their transmitting and receiving equipment and their location. The range determines the coverage area of the cell of the base station in which user equipment (LIE), such as a telephone handset, is able to establish a communications channel with the base station. Accordingly, the coverage of the network is determined by both the selection and position of the base station of the network. Coverage in remote areas is always problematic, as it is generally cost prohibitive to install a base station in an area where usage of the network is very low. Accordingly, alternatives need to be adopted in order to extend network service to users in remote locations.
One alternative for remote locations is the use of satellite telecommunications infrastructure. Satellite telephones and access charges to satellite networks are however costly. Another alternative which has been used in Australia is to place mobile handset equipment at the edge of a mobile network's coverage, and then run a fixed copper line from the handset to terminal equipment at the remote location, e.g. the user's home. This gives rise to disadvantages associated with installation and maintenance of the copper lines for users, together with the cost of having the dedicated phones placed at the edge of the network.
Two other alternatives involve the use of radio frequency (RF) repeater systems. These are:                (i) a RF repeater at the edge of the coverage of the network so as to directly retransmit or relay the RF signals to and from the donor base station of the cell and the UE at a remote location outside of the coverage area. This, however, introduces the problem of feedback between the receiving and transmitting antennas of the repeater. Attempts have been made to reduce this feedback by introducing echo cancellers to remove the original signal at the repeater from the retransmitted signal, but this has proved expensive and feedback still occurs, such as from reflections from transport vehicles moving within the area.        (ii) a two stage RF translation system including a RF translator located at the donor base station of the cell to translate the RF signals from the donor base station to a different carrier frequency to that of the network for transmission to a RF repeater located on the edge of the coverage area. The repeater in turn then translates the received RF signals from the RF translator back to the original carrier frequency for transmission to the UE. RF transmission from the UE is similarly translated at the repeater site to communicate with the RF translator and hence to the donor base station. This however is a more expensive solution than (i) and suffers the disadvantage of having to install and maintain additional equipment at the base station as well infrastructure at the repeater site.
Accordingly, it is desired to address the above, or at least provide a useful alternative.

Repeater system for extended cell coverage


A method of operating a vapor generating system, including a once-through vapor generator, wherein wet vapor is generated in the upper portion of the load range and superheated vapor is generated in the lower portion of the load range is disclosed. Generated vapor is passed through an external and remote moisture separator. Superheated vapor is desuperheated by liquid injection as it passes from the vapor generator to the moisture separator.

This invention relates to a method of operating a vapor generator system, in particular, operating a vapor generating system including a once-through vapor generator producing wet vapor at high loads and superheated vapor at low loads. More particularly, this invention relates to a method of operating the steam generating system of a steam-electric power station. Still more particularly, this invention relates to a method of operating a steam generating system, including a once-through steam generator, in a water-cooled nuclear reactor power station.
The vapor generating system of a power plant typically includes one or more vapor generators, a turbine, a condenser, a secondary coolant system and interconnecting piping. In water-cooled nuclear power stations, the vapor generators provide the interface between a reactor (primary) coolant system and the secondary coolant loop, that is, the vapor generating system. Heat generated by a reactor is transferred from the reactor coolant in the vapor generators to vaporize a secondary coolant, usually feedwater, and produce steam. The steam passes from the vapor generator to the turbine where some of its energy is used to drive the turbine. Steam exhausted from the turbine is condensed, regeneratively reheated, and pumped back to the vapor generators as feedwater.
In most pressurized water cooled nuclear steam supply systems, the steam exiting the vapor generators is routed directly to the turbine as dry or superheated steam. When once-through vapor generators are utilized, the steam is often superheated and provided at substantially constant pressure at the turbine throttle over the entire load range.
A typical once-through vapor generator employs a vertical, straight tube bundle, cylindrical shell design with shell side boiling. Hot reactor coolant enters the vapor generator through a top nozzle, flows downward through the tubes, wherein it transfers its heat, and exits through bottom nozzles before passing onto the reactor. The shell, the outside of the tubes, and the tubesheets form the vapor-producing section or secondary side of the vapor generator. On the secondary side, subcooled secondary coolant flows downward into an annulus between the interior of the shell and a tube bundle shroud, and enters the tube bundle near the lower tubesheet. As the secondary coolant flows upwardly through the tube bundle, heat is transferred from the counterflowing reactor coolant within the tubes, and a vapor and liquid mixture is generated on the secondary side ranging from zero quality at the lower tubesheet to substantially dry, one hundred percent quality vapor. The mixture becomes superheated in the upper portion of the tube bundle. The superheated vapor flows downwardly through an upper annulus between the shell and the tube bundle shroud, passes through a vapor outlet, and then onto the turbine. This arrangement insures zero moisture (superheated) vapor at the turbine throttle without the need of bulky steam drying equipment integrally associated with the vapor generators which, in nuclear power stations, are housed within a generally crowded environment in a reactor containment building where space is at a premium. Further detailed description of a once-through vapor generator may be found in U.S. Pat. No. 3,385,268.
The once-through vapor generating concept permits easily controlled operation with both constant average primary coolant temperature and constant steam pressure at the turbine throttle. To change load, the once-through vapor generator relies on a change in the proportion of boiling to superheating length in the tube bundle, that is, a trade-off between nucleate boiling and superheating. In designing and operating vapor generators, it is vital to make efficient use of the heat transfer surface. Hence, it is desirable to maintain nucleate boiling over as wide a range of vapor qualities as possible since nucleate boiling is characterized by high heat transfer coefficients and makes possible the generation of vapor with minimum heating surface. Typically, at high loads the once-through vapor generator heat transfer surface is approximately 75% in nucleate boiling and 25% in superheating; while at low loads the distribution is approximately 5% nucleate boiling and 95% superheating. Control is achieved by regulating feedwater flow to maintain constant output pressure, letting the distribution between superheating and boiling surface automatically vary as a function of load. One disadvantage of this concept is the relatively low heat transfer rate, or effectiveness, of the superheating surface at maximum load which requires more heating surface than would be needed if the heat were all transferred in the nucleate boiling mode. However, superheating is basically required to preclude moisture carry-over to the turbine, particularly during load change excursions.
Due to the single-pass, nonconcentrating characteristics of once-through vapor generators, essentially all of the soluble contaminants in the incoming secondary coolant exit from the unit dissolved in the superheated vapor, in moisture droplets that may be entrained and carried in suspension by slightly superheated vapor. In contrast, recirculating vapor generators concentrate solids in the feedfluid, and limit such concentrations by controlled blowdown. Hence, blowdown is not required in once-through vapor generators, but high quality secondary coolant is required.
In steam systems, feedwater is cleaned, for example, by condensate demineralizers prior to its introduction into the steam generator. Some contaminants remain in the feedwater regardless of the feedwater treatment utilized. Small quantities of common contaminants in feedwater chemistry can be tolerated and feedwater chemical specifications make appropriate allowances therefor. However, if the feedwater contaminants exceed limits allowed by the chemical specifications, either due to variations during normal operating conditions or during load transients, contaminants may be deposited within the turbine where corrosion damage can result due to the buildup and concentration of solids, particularly sodium compounds. Allowable sodium concentrations may be as low as 1 ppb. Unfortunately, a greater proportion of sodium compounds to total solids seems to be present when condensate polishing is used.
Thus, there exists a need to develop operating techniques for vapor generating systems including once-through vapor generators which further minimize contaminant deposition in the turbine and which minimize the disadvantages of utilizing steam generator heat transfer surface for superheating.


A tongue assembly for use in a three-point continuous loop seat belt system is freely slidable along the belt to enable use of a light retractor spring. The tongue assembly includes a lock bar slidable along a base. The base has a flat leading end portion, a parallel offset trailing end position, and a connector section extending at an angle between the leading and trailing end portions. Whe the tongue assembly is engaged with the buckle, the belt wraps around the lock bar, and the lock bar is slid along the angled connector portion of the base toward the trailing end portion. The belt is clamped between the lock bar and the trailing end portion, to restrain the vehicle occupant. When the tongue assembly is disengaged from the buckle, the belt extends through the tongue assembly in such a manner that the belt may move freely through the tongue assembly. Since the belt may move freely through the tongue assembly, the retractor wind-up spring need not be strong enough to lift both the belt and the tongue assembly, and a light retractor spring may be used.

1. Field of the Invention
This invention relates to a tongue assembly for use in a safety apparatus having a belt for restraining an occupant of a vehicle against movement relative to the vehicle. More specifically, this invention relates to a free-running tongue assembly for use in a three-point continuous loop safety belt system.
2. Prior Art
Three-point continuous loop safety belt systems include a safety belt upon which a tongue assembly is slidably mounted. When the safety belt is to be connected to restrain an occupant of a vehicle, the belt is withdrawn from a retractor and the tongue assembly is connected with a buckle. When the tongue assembly is released from the buckle, the belt is wound on the retractor into a stowed position.
In a standard tongue assembly, there is a high level of friction between the tongue assembly and the belt, and the retractor spring is not strong enough to pull the belt through the tongue assembly. As the retractor rewinds the belt, both the belt and the tongue assembly are pulled upwardly by the retractor. If the tongue assembly comes up against the D-ring or retractor before retraction is completed, retraction stops because the retractor cannot pull the belt through the tongue assembly. Some belt webbing is left loose and unretracted. Since both the belt and the tongue assembly are lifted by the retractor, the retractor must have a relatively strong wind-up spring, capable of exerting enough force on the belt to lift the combined weight of the belt and tongue assembly. When the belt is in use, the relatively large force exerted by the retractor wind-up spring results in the belt being pulled across the torso of an occupant of the vehicle with a force which some occupants may find to be objectionably large.
A second type of tongue assembly is known in which there is less friction between the belt and the tongue assembly. However, enough friction remains so that the tongue does not fall freely toward the floor but rather is lifted to the D-ring or retractor. When the tongue assembly contacts the D-ring or retractor, the retractor pulls the belt through the tongue assembly, and excess webbing is stowed onto the retractor. The retractor spring must be strong enough to lift the tongue and overcome the friction between the belt and tongue.
Other systems have been designed with even less friction. U.S. Pat. No. 4,551,889 discloses a self-locking adjust tongue assembly which, when unlatched, has a lock bar depressed from the plane of the base, to permit the adjust tongue to fall freely along the belt when the belt assumes a near vertical position. U.S. Pat. No. 3,941,419 discloses a buckle component which is free to slide down the belt when the belt is in a vertical stored orientation. Co-pending U.S. patent application Ser. No. 280,148 entitled "Tongue Assembly", filed Dec. 5, 1988 by Alexander P. Kotikovsky et al., U.S. Pat. No. 4,878,272 assigned to the assignee of the present application, discloses a tongue assembly through which a belt extends with first and second straight portions having an included angle between them of at least 154.degree., so that the tongue assembly is able to slide on the belt under the influence of gravity. Co-pending U.S. patent application Ser. No. 256,983, filed Oct. 13, 1988 by Alexander P. Kotikovsky entitled "Tongue Assembly" and assigned to the assignee of the present application, discloses a tongue assembly in which there is a minimum amount of friction between the belt and the tongue assembly, so that the two can move easily relative to each other.


Disclosed are tents and tent support frames. A tent support frame includes a rotatable connector and tent support poles. The rotatable connector includes first and second connectors configured to be coupled in a vertical direction with one above another, and rotatable with respect to each other. The first connector includes a first through-hole in a horizontal direction, and the second connector includes a second through-hole in the horizontal direction. Tent support poles include a first tent support pole configured to pass through the first through-hole of the first connector, and a second tent support pole configured to pass through the second through-hole of the second connector.

Nowadays, people like outdoor activities and often go out on weekends or holidays. Consequently, there is an increasingly high demand for outdoor gear such as tents. There are mainly two types of tents available on the market. One type of tents is assemblable. This type of tents has supports formed by sets of poles connected to each other. The supports are independent and separated from each other. As such, the setting up of the tent is time-consuming and physically demanding. Moreover, through-holes for inserting the supports to set up the tent have to be sewn. The independent and separate supports also make the setting up of the tent difficult and make the tent unstable. The other type of tents is foldable. Main issues with the current foldable tents include their high manufacturing costs and large size when folded. To realize the integrated folding/unfolding of the tent support and the tent, structural parts, such as connectors and extensible members, need to be added to the tent support, and the tent support and the tent fabric need to be assembled in advance. This significantly increases material cost and labor cost. In addition, the structural parts for realizing the integrated folding/unfolding and connection of the tent supports increase the size of the tent when folded.
Given the above background, there is a need in the art for tent support frames and tents that address the above-mentioned problems.
The information disclosed in this Background section is provided for an understanding of the general background of the invention and is not an acknowledgement or suggestion that this information forms part of the prior art already known to a person skilled in the art.

Tent and tent support frame having support poles coupled by rotatable connector

Xiamen Innovation Metal Products Co., Ltd.