Patent Publication Number: US-2021172268-A1

Title: Clamp Assembly

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This patent application claims the benefit of priority to GB Patent Application No. 1917817.7, filed on 5 Dec. 2019, which application is incorporated herein by reference in its entirety, 
     TECHNOLOGICAL FIELD 
     The present application relates to a clamp assembly, typically for handling two conduits connected together and particularly for making and/or optionally breaking connections between the conduits and optionally for servicing components of the conduits at the connection, for example seals, bearings or other components accessible at the connection. In some examples, conduits are flowline conduits on opposite sides of a connection flowing fluids to or from an oil or gas well. 
     BACKGROUND 
     EP0852996 discloses apparatus for fusing plastic pipes. DE102006026334 discloses a device for joining subsea pipelines. 
     SUMMARY 
     According to one or more embodiments there is provided a clamp assembly adapted for breaking a connection in a pressurised flowline of an oil or gas well. The clamp assembly may include:
         first and second clamp members, each of the first and second clamp members having at least first and second interconnected clamp segments, the first clamp segment being pivotally moveable with respect to the second clamp segment to close the clamp segments around a conduit;   at least one first guide rod with a first axis connecting a first clamp segment of the first clamp member to a first clamp segment of the second clamp member, and at least one second guide rod with a second axis connecting a second clamp segment of the first clamp member to a second clamp segment of the second clamp member, wherein the first and second axes of the first and second guide rods are parallel;   a drive mechanism connecting the first clamp member to the second clamp member, wherein the drive mechanism is adapted to drive axial movement of the first and second clamp members relative to each other in a direction parallel to the first and second axes;   wherein the first and second clamp members are adapted to engage with the conduit when the clamp segments are closed around the conduit, and wherein the first and second guide rods are adapted to permit relative axial movement of the first and second clamp members in a direction parallel to the first and second axes while maintaining alignment of the first and second clamp members.       

     Optionally the clamp assembly is adapted to handle (for example to separate and optionally make up) connections in large bore conduits, for example connections of pressurised flowlines used to flow high-pressure fluid to and optionally from the bores of oil and gas wells, for example during hydraulic fracturing operations. Optionally the diameter of the bore of the conduit is larger than 4 inches, optionally larger than 5 inches (0.127 metres), optionally from 5 inches to 8 inches (0.203 metres), or optionally approximately 7⅝ths inches (0.194 metres). Optionally the diameter of the bore of the conduit is less than 15 inches (0.381 metres), optionally less than 10 inches (0.254 metres), optionally less than or equal to 8 inches (0.203 metres). Optionally the connection is between two sections of the conduit. Optionally the two sections of the conduit are relatively moveable when the connection is made up, for example, some connections handled by the clamp assembly could permit pivotal movement of the conduit sections, e.g. rotation of one section in relation to the other, e.g. around the axis of at least one of the sections when the connection is made up and operational. In the case of conduits which permit relative movement of adjacent conduit sections on either side of a connection, such as articulating flowlines, the connections often comprise one or more components which can require routine maintenance or replacement, such as bearing rings and seals e.g. annular seals. 
     Optionally the conduits are flowline conduits adapted for use in oil and gas wells for flowing fluids into or out of the well. 
     Optionally the clamp assembly allows in-field separation and makeup (e.g. at the site of the wellbore) of conduit connections. Optionally the clamp assembly provides access to the internal components of a conduit or conduit connection for cleaning, maintenance or replacement. This allows for a significant reduction in the duration of interruption of wellbore operations, such as hydraulic fracturing operations, required for maintenance and replacement of connection components, and also typically reduces the difficulty of such operations. The pivotally interconnected clamp segments of the first and second clamp members also advantageously allow rapid deployment and installation of the clamp assembly, compared to other tools which may comprise two or more separate components which must be assembled each time in the course of deployment and installation. 
     Since the clamp assembly comprises a first clamp member having at least first and second interconnected clamp segments, each of which are connected or attached to corresponding clamp segments of a second clamp member, the entire clamp assembly can optionally be lifted or suspended from a single lifting point e.g. a lifting eye or ring. Furthermore, the entire clamp assembly can optionally be lifted or manoeuvred by a single lifting device (which might be for example a crane or a forklift, optionally having a capacity of at least 100 to 500 kg). Optionally the clamp assembly (and optionally the one or more lifting points of the clamp assembly) are capable of at least partially supporting the weight of the conduits adjacent the conduit connection, as well as the clamp assembly itself, which can advantageously reduce the requirements for ancillary support structures to support the conduits while the clamp assembly is used to separate the conduit connection. 
     Optionally first and second clamp segments of the first clamp member are constrained to pivot synchronously with each other, and similarly, the first and second clamp segments of the second clamp member are constrained to pivot synchronously with each other. Optionally this constraint is facilitated by the first and second guide rods. For example, a guide rod could have a sliding section held in an orientation bore which permits sliding of at least one section of the guide rod through the orientation bore while resisting misalignment of the section of the guide rod with the orientation bore, for example, by providing a close tolerance between the orientation bore and the guide rod. Thus pivotal movement of a clamp segment on one clamp member urges corresponding pivotal movement of the corresponding clamp segment on the other clamp member, at the same rate. Optionally the first and second guide rods could be telescopic in other examples. 
     Optionally the first and second clamp segments of each of the first and second clamp members are constrained to move axially synchronously with each other. 
     Optionally the first and second clamp members have a first (optionally axial) degree of freedom of movement, and optionally the at least first and second clamp segments (optionally corresponding first and second clamp segments of the first and second clamp members) have a second (optionally rotational) degree of freedom of movement, which can optionally be perpendicular to the first degree of freedom of movement. Optionally the at least first and second clamp segments are pivotally moveable in a plane that is perpendicular to the axis of movement of the first and second clamp members. Optionally the first and second clamp segments pivot around a pivot connection that is parallel to the first and second axes. The first and second axes of the at least one first and second guide rods are optionally parallel with the axis of movement of the drive mechanism. The first and second axes of the at least one first and second guide rods are also optionally parallel with an axis of the first degree of freedom of movement of the first and second clamp members, which is optionally parallel to an axis of the conduit when the first and second clamp segments are closed around the conduit. Optionally the first and second axes are spaced apart from one another. 
     Optionally the various ranges of freedom of movement of the various parts are constrained. For example, while the first and second clamp members are movable in the first and second degrees of freedom, they are also optionally constrained to move only within those degrees of freedom, e.g. only axially apart, and only rotationally around the pivot connection between the clamp segments, and the assembly is optionally arranged such that movement along other axes, or around other axes, is resisted or restricted or even substantially prevented. This helps the assembly to maintain alignment of the two conduits on opposite sides of the connection during breaking, so that the two conduits separate only by axial movement, while retaining the alignment of their axes, and the parallel orientation of the clamp members attached to the conduit, thus facilitating makeup of the conduits after servicing is complete. This helps to reduce non-axial movement, e.g. sway, yaw and pitch of the conduit sections relative to one another when the sections are separated, and thereby assist with fast and accurate re-assembly after completion of maintenance operations on the connection. 
     Optionally the clamp segments forming the first and second clamp members are formed from a metallic material, optionally aluminium, optionally high-strength aluminium. Optionally each clamp segment is formed e.g. cut, machined or milled from a single integral piece e.g. a single plate or block of material. 
     Optionally a recess is formed in an inner surface of each clamp segment, optionally by cutting or milling, which is optionally at least partially annular. 
     Optionally redundant or excess portions of each clamp segment can be removed, optionally by machining or milling, during or optionally after production of the clamp segment, optionally to reduce the weight of the clamp assembly. 
     Optionally each clamp segment of the first and second clamp members comprises at least two, optionally parallel plates which are spaced apart from each other, optionally in an axial direction. Optionally the inner surface of each clamp segment is at least partially arcuate, optionally concave, and optionally at least partially semi-circular. Optionally the inner surfaces of the at least two plates are aligned with each other in an axial direction. 
     Optionally at least a part of the inner surface of each clamp segment comprises an annular portion. Optionally each annular portion on each segment has the same radius. Optionally when the clamp segments are closed, the annular portion(s) on each segment engage arcuate parts of the outer surface of the flowline. Optionally the radius of the annular portions of the clamp segments matches the radius of the arcuate parts of the outer surface of the flowline. Optionally when the clamp segments are closed, the annular portions of the inner surfaces lie on a circle. Optionally the circle has a centre that is coincident with the axis of axial movement of the first and second clamp members. 
     Optionally a recess is formed in each of the first and second clamp members. Optionally the recess can be disposed between the plates of the clamp segment. Optionally the recess is at least partially annular. Optionally the recess in one clamp member is parallel to the recess in the other clamp member. Optionally the recesses are perpendicular to the axis of at least one or more of the first and second guide rods, conduit and drive mechanisms. 
     Optionally a recess is disposed on the inner surface of each clamp member, e.g. on an inner surface of at least one clamp segment, optionally on an inner surface of each clamp segment. Optionally each recess is adapted to engage with at least one protrusion (e.g. a lip or a shoulder) on an outer surface of the conduit connection. Optionally the protrusion is at least partially annular and can optionally extend circumferentially around the conduit sections, for at least a part of the distance around the outer surface of the conduit sections. Optionally the axial dimension of the recess of each clamp segment corresponds to an axial dimension of its associated protrusion. Optionally each recess is adapted to receive at least one protrusion. Optionally the recesses of the first and second clamp members engage with the protrusions on the conduit sections either side of the conduit connection to break the connection, optionally by axially separating the conduit sections. Optionally the clamp members remain engaged with the conduit sections to re-make the conduit connection, optionally by axially closing the conduit sections. 
     Optionally the outer surface of each clamp segment is generally arcuate, and optionally convex. Optionally the recess formed between the inner surfaces of the plates is a closed recess. 
     Optionally each clamp segment has a generally U- or C-shaped profile. Optionally one or more support points for at least one guide rod, and optionally for at least one drive mechanism, are disposed on the outer surface of each clamp segment. 
     Optionally each clamp member, and optionally each clamp segment, has at least one lifting point, e.g. a padeye. 
     Optionally the at least first and second clamp segments of each clamp member are interconnected by a pivot connection such as a hinge. Optionally the pivot connection is disposed at a distal end of each of the at least first and second clamp segments. Optionally the pivot connection allows the at least first and second clamp segments to pivot e.g. rotate relative to each other in each clamp member. Optionally the pivotal movement is constrained within a limited range. For example, optionally the at least first and second clamp segments can rotate between 60 degrees and 120 degrees relative to each other, and optionally between 60 degrees and 100 degrees relative to each other. 
     Optionally the first and second clamp members each have an open configuration in which the ends of the clamp segments distal to the pivot connection are spaced apart, and a closed configuration in which the said ends of the clamp segments are closer together than in the open configuration. Optionally a first clamp segment (optionally each first clamp segment of the first and second members) comprises a latching device adapted to latch (e.g. releasably latch) the first clamp segment to another clamp segment (e.g. the second clamp segment) of the same clamp member, optionally when the clamp segments of the clamp member are closed around the conduit (i.e. in the closed configuration). Optionally the one or more latching devices are disposed at an opposing distal end of the first clamp segments from the pivot connection. Optionally the latching devices have an unlocked (e.g. open) position, in which relative pivotal movement of the first and second clamp segments is permitted, and optionally the latching devices have a locked (e.g. closed) position, in which relative pivotal movement of the first and second clamp segments is restricted. Optionally the latching devices are tethered e.g. permanently connected to the first clamp segments in each of the unlocked and the locked positions, and optionally the latching devices cannot be separated from the first clamp segments in either of the unlocked and the locked positions. Optionally the latching devices comprise swing bolts tethered to one of the clamp segments (e.g. the first clamp segment) by a pivot connection which permits the swing bolt to move between the unlocked and locked positions around the pivot connection without detaching from the first clamp segment. 
     Optionally the first guide rod is fixed to the first clamp segment at only one end, and at the other end, the first guide rod has a sliding connection to the other first clamp segment. Optionally the second guide rod is fixed to the second clamp segment at only one end, and at the other end, the second guide rod has a sliding connection to the other second clamp segment. 
     Optionally at least two first guide rods are connected between the first clamp segments of the first and second clamp members, and optionally at least two second guide rods are connected between the second clamp segments of the first and second clamp members. 
     Optionally the first and second guide rods maintain alignment of the first and second clamp members as they move axially relative to each other, which optionally facilitates smooth relative movement of the first and second clamp members, and optionally reduces friction due to misalignment of the first and second clamp members. Optionally the axial length of at least one of the first and second guide rods is constant. Optionally each of the first and second guide rods is fixed to one of the clamp members and optionally has an axially movable connection (e.g. a sliding connection) with the other of the clamp members. Optionally the axially movable connection is provided by a bearing aperture in the said other of the clamp members through which the guide rod passes. Optionally at least one guide rod comprises a bearing rod. Optionally the at least one aperture comprises a bearing device such as a ball bearing, optionally a linear ball bearing, optionally a linear roller bearing. 
     Optionally the aperture receiving the guide rod maintains alignment of the guide rod during axial movement, e.g. by the bearing device. Optionally the bearing device permits axial movement of the second clamp member relative to the guide rod, and optionally restricts (optionally substantially prevents) non-axial movement (e.g. pitch and/or yaw) of the second clamp member relative to the guide rod. Optionally the bearing device supports the guide rod in a perpendicular orientation relative to the second clamp member. Optionally the rate of axial movement of the said other of the clamp members relative to each guide rod is equal. 
     Optionally at least one guide rod comprises an indicator, which optionally indicates that the first and second clamp members are axially separated by a predetermined distance. Optionally the predetermined distance between the first and second clamp members corresponds to the axial distance between the protrusions on opposing conduits of the conduit connection before the connection is separated. Optionally the indicator allows the axial distance between the first and second clamp members to be set equal to the axial distance between the protrusions on each opposing conduit of the connection, optionally before the first and second clamp members engage with the conduits. Optionally the indicator comprises a mark (e.g. a groove), which optionally aligns with a surface (optionally an axially inner surface) of the second clamp member when the first and second clamp members are axially separated by the predetermined distance. 
     Optionally at least one guide rod (optionally each of the guide rods) has a locking device to lock the connection between a clamp member (optionally the second clamp member) and the at least one guide rod. Optionally the locking device restricts relative axial movement between the second clamp member at least one guide rod, and optionally the locking device restricts relative axial movement of the first and second clamp members, optionally while permitting pivotal movement of the two clamp members to close and open around the conduit. Optionally the locking device comprises an elongate member (e.g. a rod or pin) adapted to be received through an aperture in at least one guide rod, and optionally in at least one cap or collar fixed to a clamp member (optionally the second clamp member). Optionally each collar is fixed to a bearing device disposed within an aperture in the second clamp member. Optionally the locking device is attached (e.g. tethered) to a clamp member (optionally the second clamp member). 
     Optionally the locking device is received through an aperture in the at least one guide rod, and optionally through at least one collar when the apertures are aligned. Optionally the apertures in the at least one guide rod and collar are aligned when the first and second clamp members are axially separated by a second predetermined distance. Optionally the second predetermined distance is greater than the first predetermined distance, and optionally the second predetermined distance corresponds to an axial distance between the at least one protrusion on opposing sections of the conduit connection after the connection is separated. Optionally the locking device can be engaged to restrict or substantially prevent relative axial movements of the first and second clamp members when the clamp members are axially separated by the second predetermined distance. When the locking device is engaged, relative axial movement of the first and second clamp members, optionally due to loss of power to the first and second drive mechanisms, or optionally due to inadvertent activation of the first and second drive mechanisms, is restricted or substantially prevented. Optionally each guide rod has a respective locking device. 
     Optionally a first drive mechanism connects a first clamp segment of the first clamp member to a first clamp segment of the second clamp member, and optionally a second drive mechanism connects a second clamp segment of the first clamp member to a second clamp segment of the second clamp member. Optionally the first and second drive mechanisms are adapted to drive axial movement of the first and second clamp members relative to each other in a direction parallel to the first and second axes. Optionally the first and second drive mechanisms resist movement of the first and second segments out of parallel alignment with one another during axial movement, optionally by synchronous driving of the first and second drive mechanisms. Optionally at least one drive mechanism is connected (e.g. fixed) to the first and second clamp members at respective first and second axial ends of the at least one drive mechanism. 
     Optionally the axial length of the at least one drive mechanism is variable. Optionally at least one drive mechanism is telescopic, and varies its axial length by telescoping. Optionally the drive mechanism comprises at least first and second portions, and optionally the first and second portions are adapted to axially overlap with each other, or optionally a first portion is received inside a second portion. Optionally the at least one drive mechanism comprises a hydraulic cylinder and piston arrangement. Optionally the or each cylinder and piston arrangement has a first end connected to the first clamp member and a second end connected to the second clamp member and is optionally arranged along an axis that is parallel to the first and second axes. 
     Optionally the first and second drive mechanisms share at least one common drive actuation system. Optionally the first and second drive mechanisms share a first common drive actuation system, which optionally permits synchronised actuation of the first and second drive mechanisms in a first direction (optionally in a first linear direction, optionally to axially extend the first and second drive mechanisms, optionally to increase the axial distance between the first and second clamp members). Optionally the first and second drive mechanisms are synchronised. In some examples, the first and second drive mechanisms share a second common drive actuation system, which optionally permits synchronised actuation of the first and second drive mechanisms in a second opposing direction (optionally in a second linear direction, optionally to axially retract the first and second drive mechanisms, optionally to decrease the axial distance between the first and second clamp members). Optionally the first and second common drive actuation systems each produce equal (optionally balanced) driving forces in each of the first and second drive mechanisms. Optionally the equal driving forces in each of the first and second drive mechanisms maintain alignment of the first and second clamp members as they move between axially retracted and expanded positions. Optionally the first and second drive mechanisms can drive the first and second clamp members in one direction only, e.g. apart, or together. Optionally movement in the opposite direction can be passive, or driven by another mechanism. Optionally the first and second drive mechanisms drive axial movement along an axis that is parallel to the guide rods. 
     Optionally the common drive actuation system comprises a hydraulic circuit, optionally comprising a hydraulic fluid reservoir containing pressurised hydraulic fluid, which is optionally in fluid communication with the first and second drive mechanisms through first and second fluid lines. Optionally pressurised hydraulic fluid in the first fluid line actuates the first and second drive mechanisms in a first direction, optionally extending the pistons of first and second hydraulic cylinders. Optionally pressurised hydraulic fluid in the second fluid line actuates the first and second drive mechanisms in an opposing second direction, optionally retracting the pistons of first and second hydraulic cylinders. 
     Optionally the at least one drive mechanism comprises an extension mechanism adapted to axially extend the drive mechanism, and optionally to increase the axial distance between the first and second clamp members. Optionally the at least one drive mechanism comprises a retraction mechanism adapted to axially retract the drive mechanism, and optionally to decrease the axial distance between the first and second clamp members. 
     Optionally where first and second drive mechanisms are provided, the extension mechanisms of the first and second drive mechanisms are operatively linked, and optionally the retraction mechanisms of the first and second drive mechanisms are operatively linked. Optionally the operatively linked extension mechanisms produce an equal driving force in the first and second drive mechanisms (optionally on the push stroke of at least one hydraulic cylinder), and optionally the operatively linked retraction mechanisms also produce an equal driving force (optionally on the pull stroke of at least one hydraulic cylinder), optionally in an opposing direction to the driving force produced by the extension mechanisms. Optionally the operatively linked extension and retraction mechanisms of the first and second drive mechanisms drive axial movement of the first and second clamp members synchronously with each other, optionally maintaining alignment of the first and second clamp members. 
     Optionally the clamp assembly further comprises at least one clamp portion removal mechanism, which is optionally adapted to remove (optionally to support) at least one portion of the conduit connection, optionally a housing around the conduit connection, optionally a clamp around the conduit connection. Optionally the clamp assembly comprises two clamp portion removal mechanisms. Optionally a first clamp portion removal mechanism is disposed on a first clamp segment of the first clamp member, and optionally a second clamp portion removal mechanism is disposed on a second clamp segment of the first clamp member. Optionally the clamp portion removal mechanisms are adapted to remove portions of the conduit connection from opposing sides of the conduit connection, and optionally to remove portions of the conduit connection in opposing radial directions relative to the conduit connection. Optionally the at least one clamp portion removal mechanism facilitates easy removal of one or more portions of the conduit connection which must be removed to gain access to the internal components of the conduit connection, and optionally reduces the time required to replace the one or more portions of the conduit connection. 
     Optionally the at least one clamp portion removal mechanism comprises a rail, and optionally a bracket. Optionally the bracket is pivotally connected to the rail (optionally at a distal end of the rail), and optionally the rail has a sliding connection with the first clamp member, optionally with a first or second clamp segment of the first clamp member. Optionally the rail is slidable, optionally in a generally radial direction relative to the conduit connection, optionally in a direction perpendicular to the axes of the first and second guide rods. Optionally the bracket is movable in a first direction (optionally generally away from the conduit connection) and an opposing second direction (optionally generally toward the conduit connection). Optionally the rails of the first and second clamp portion removal mechanisms are disposed approximately parallel to each other, and optionally the first direction of movement (e.g. away from the conduit connection) of each of the brackets of the first and second clamp portion removal mechanisms are in opposing directions, optionally in opposing radial directions relative to the conduit connection. 
     Optionally the bracket of each clamp portion removal mechanism rotates relative to the rail, optionally in a plane that is parallel with the rail, and optionally parallel to the axes of the first and second guide rods. Optionally the bracket is connected to the rail by a pivot connection. Optionally the bracket rotates at least 90 degrees, optionally from 90 degrees to 180 degrees, optionally approximately 180 degrees, typically around the pivot connection. Optionally the bracket rotates from a first position, in which it optionally faces away from the conduit connection, to a second position, in which it optionally faces toward the conduit connection. Optionally the bracket is adapted to be removably connected to a portion of the conduit connection. Optionally the bracket receives a fixing or fastener, optionally to temporarily secure it to a portion of the conduit connection, optionally while the portion of the conduit connection is joined to the conduit connection. 
     Optionally the sliding (optionally linear) movement of the rail, and optionally the pivotal (optionally rotational) movement of the bracket, allow at least one portion of the conduit connection to be removed (e.g. displaced) from the conduit connection (and optionally allowing substantially unobstructed access to the conduit connection), while remaining fixed to the clamp assembly. 
     Optionally the rail of each clamp portion removal mechanism incorporates a restraint mechanism, which optionally restricts, optionally substantially prevents, sliding movement of the rail relative to the first clamp member. Optionally the rail restraint mechanism comprises a rail brake, which is optionally tightened or loosened (optionally manually e.g. by hand) to respectively restrain or release the rail. Optionally the rail restraint mechanism can be engaged when the rail is in any position relative to the first clamp member. 
     Optionally the bracket of each clamp portion removal mechanism incorporates a restraint mechanism, which optionally restricts, optionally substantially prevents, rotational movement of the bracket relative to the rail. Optionally the bracket restraint mechanism comprises a locking pin, which is optionally inserted or removed through the bracket and the rail to respectively lock or free the bracket. Optionally the bracket restraint mechanism can be engaged only when the bracket is orientated in (optionally close to) its positions of maximum rotation relative to the rail, 
     A method of breaking a connection in a pressurised flowline of an oil or gas well is also provided. The method may include using a clamp assembly. The clamp assembly may include:
         first and second clamp members, each of the first and second clamp members having at least first and second interconnected clamp segments, the first clamp segment being pivotally moveable with respect to the second clamp segment;   at least one first guide rod with a first axis connecting a first clamp segment of the first clamp member to a first clamp segment of the second clamp member, and at least one second guide rod with a second axis connecting a second clamp segment of the first clamp member to a second clamp segment of the second clamp member, wherein the first and second axes of the first and second guide rods are parallel; and   a drive mechanism connecting the first clamp member to the second clamp member,   wherein the method comprises:   closing the clamp segments of the first and second clamp members around the conduit and engaging the first and second clamp members with the flowline; and   driving axial movement of the first and second clamp members away from each other to break the conduit connection, wherein the guide rods permit relative axial movement of the first and second clamp members in a direction parallel to the first and second axes while maintaining alignment of the first and second clamp members.       

     Optionally the method includes rotating the clamp assembly around the conduit connection after the first and second clamp members have been closed around the conduit connection, optionally before driving axial movement of the first and second clamp members to break the conduit connection. Optionally the latching devices for latch the first clamp segments to the second clamp segments can be partially locked (optionally partially tightened) while rotating the clamp assembly around the conduit connection,. 
     Optionally the method includes driving axial movement of the first and second clamp members toward each other to re-make the conduit connection while the first and second clamp members are closed around the conduit connection, 
     In one or more embodiments, a bearing ring removal tool may include:
         a cam member having one or more first and second cam surfaces at a first distal end, wherein the first and second cam surfaces are rotated by a force applied to an opposing second distal end of the cam member;   and a drive arm, the drive arm being pivotally connected to the cam member at a pivot point adjacent to the first and second cam surfaces,   wherein the cam member drives movement of the drive arm,   and wherein the first cam surface is spaced apart from the second cam surface,   and wherein the minimum radius of the second cam surface around the pivot point is greater than the maximum radius of the first cam surface around the pivot point.       

     Optionally the cam member drives movement of the drive arm in a direction perpendicular to a follower surface with which the first and second cam surfaces engage. 
     Optionally the first cam surface is arcuate, and optionally forms a portion of a circle e.g. an arc of a circle. Optionally the second cam surface is arcuate, and optionally forms a portion of a circle e.g. an arc of a circle. Optionally the radius of the arc of the first cam surface is larger than the radius of the arc of the second cam surface, 
     optionally at least 2, or 3, or 5 times as large. Optionally the centres of the arcs of the first and second cam surfaces are offset from each other, and are optionally aligned on an axis passing through the pivot point. Optionally the centre of the arc of the first cam surface is closer to the pivot point than the centre of the arc of the second cam surface. Optionally the pivot point is disposed on an axis of the cam member. 
     Optionally the centres of the arcs of the first and second cam surfaces and the pivot point are aligned on the axis of the cam member. 
     Optionally the cam member comprises first and second segments, which are optionally symmetrical. Optionally a first cam surface and a second cam surface is disposed at distal ends of both the first and second cam member segments. Optionally the opposing second distal ends of the cam member segments are interconnected, optionally by a force application segment, optionally by a handle. Optionally a pivot point is disposed on the first and second cam member segments, and optionally the drive arm is pivotally connected to the first and second cam member segments, optionally at the distal ends of the drive arm. 
     Optionally an inner portion of the drive arm (optionally intermediate the distal ends of the drive arm) is arcuate, optionally semi-circular. Optionally the plane of the notional circle forming the semi-circular portion of the drive arm is oriented perpendicular to the direction of movement of the drive arm, and is optionally orientated parallel with the follower surface with which the first and second cam surfaces of the cam member are engaged. Optionally a portion (optionally the inner portion) of the drive arm is adapted to engage with a bearing ring, optionally with a radially extending lip (optionally a circumferential lip) disposed on an outer surface of the bearing ring. 
     Optionally the first and second cam surfaces contact the follower surface in sequence. Optionally when the first cam surface is engaged with the follower surface, the second cam surface is spaced apart from the follower surface, and optionally when the second cam surface is engaged with the follower surface, the first cam surface is spaced apart from the follower surface. Optionally the rate of movement of the pivot point (and optionally of the drive arm) is lower as the first cam surface rotates (optionally against the follower surface), and higher as the second cam surface rotates (optionally against the follower surface). Optionally the force produced by the drive arm (optionally against the bearing ring) is greater as the first cam surface rotates (optionally against the follower surface), and less as the second cam surface rotates (optionally against the follower surface). 
     Various aspects of one or more embodiments will now be described in detail with reference to the accompanying figures. Still other aspects, features, and advantages are readily apparent from the entire description thereof, including the figures, which illustrates a number of exemplary aspects and implementations. One or more embodiments are also capable of other and different examples and aspects, and its several details can be modified in various respects, all without departing from the spirit and scope of the present invention. Accordingly, each example herein should be understood to have broad application, and is meant to illustrate one possible way of carrying out the invention, without intending to suggest that the scope of this disclosure, including the claims, is limited to that example. Furthermore, the terminology and phraseology used herein is solely used for descriptive purposes and should not be construed as limiting in scope. In particular, unless otherwise stated, dimensions and numerical values included herein are presented as examples illustrating one possible aspect of the claimed subject matter, without limiting the disclosure to the particular dimensions or values recited. All numerical values in this disclosure are understood as being modified by “about”. All singular forms of elements, or any other components described herein are understood to include plural forms thereof and vice versa. 
     Language such as “including”, “comprising”, “having”, “containing”, or “involving” and variations thereof, is intended to be broad and encompass the subject matter listed thereafter, equivalents, and additional subject matter not recited, and is not intended to exclude other additives, components, integers or steps. Likewise, the term “comprising” is considered synonymous with the terms “including” or “containing” for applicable legal purposes. Thus, throughout the specification and claims unless the context requires otherwise, the word “comprise” or variations thereof such as “comprises” or “comprising” will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers. 
     Any discussion of documents, acts, materials, devices, articles and the like is included in the specification solely for the purpose of providing a context for the present invention. It is not suggested or represented that any or all of these matters formed part of the prior art base or were common general knowledge in the field relevant to the present invention. 
     In this disclosure, whenever a composition, an element or a group of elements is preceded with the transitional phrase “comprising”, it is understood that we also contemplate the same composition, element or group of elements with transitional phrases “consisting essentially of”, “consisting”, “selected from the group of consisting of”, “including”, or “is” preceding the recitation of the composition, element or group of elements and vice versa, In this disclosure, the words “typically” or “optionally” are to be understood as being intended to indicate optional or non-essential features of the invention which are present in certain examples but which can be omitted in others without departing from the scope of the invention. 
     References to directional and positional descriptions such as upper and lower and directions e.g. “up”, “down” etc. are to be interpreted by a skilled reader in the context of the examples described to refer to the orientation of features shown in the drawings, and are not to be interpreted as limiting the invention to the literal interpretation of the term, but instead should be as understood by the skilled addressee. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the accompanying drawings:  FIGS. 1 a  and 1 b    are respectively perspective and end elevation views of an example of a clamp assembly; 
         FIGS. 2 a  and 2 b    are perspective views of the clamp assembly shown in  FIG. 1 , illustrating the clamp segments in the closed position and the clamp members in the axially retracted position; 
         FIGS. 3 a  and 3 b    are respectively a perspective view of the clamp assembly shown in  FIG. 1 , and a detailed section view of a guide rod locking device; 
         FIG. 4  is a side section view of a flowline connection; 
         FIGS. 5 a  and 5 b    are respectively perspective and side elevation views of an example of a bearing ring removal tool; 
         FIGS. 6 a  and 6 b    are perspective views of the clamp assembly shown in  FIG. 1 , respectively illustrating the clamp assembly rotated around the flowline connection to provide access for the bearing ring removal tool shown in  FIGS. 5 a  and 5 b    which is engaged with a separated flowline connection, and the same flowline connection with the bearing ring removed and the clamp assembly rotated back to its initial position; 
         FIGS. 7 a  to 7 l    are a sequence of perspective views of a second example of a clamp assembly which includes optional clamp removal gantries, showing sequential steps in one possible mode of operation of the second example; and 
         FIG. 7 m    is a view of a possible modification of the clamp assembly in  FIGS. 7 a -7 l   , showing internal detail of a possible recess with more than one slot. 
     
    
    
     DETAILED DESCRIPTION 
     Referring now to the drawings, a first example of a clamp assembly  1  in accordance with one or more embodiments is shown in  FIG. 1   a.  The clamp assembly  1  comprises first and second clamp members  10 ,  11 . In this example first clamp member  10  comprises first and second clamp segments  20   a,    20   b,  and second clamp member  11  comprises first and second clamp segments  30   a,    30   b,  but in other examples each clamp member  10 ,  11  may comprise more than two clamp segments. The first and second clamp segments  20   a,    20   b  of the first clamp member  10  are connected by a hinge  12   a,  and the first and second clamp segments  30   a,    30   b  of the first clamp member  11  are connected by a hinge  12   b.  Also in this example the first clamp segments  20   a,    30   a  of clamp members  10 ,  11  are interconnected by two guide rods  40   a,    40   b  and a hydraulic cylinder  50 , and the second clamp segments  20   b,    30   b  of clamp members  10 ,  11  are interconnected by two guide rods  41   a,    41   b  and a hydraulic cylinder  51 . In other examples there may be more or fewer guide rods, or more hydraulic cylinders, and the numbers of guide rods and hydraulic cylinders need not be equal (or in the other words, symmetrical) between the first clamp segments  20   a,    30   a  and the second clamp segments  20   b,    30   b.  In this example, the axes of the guide rods  40   a,    40   b,    41   a,    41   b  and hydraulic cylinders  50 ,  51  (axis X of guide rod  41   a  and axis X′ of guide rod  41   b  shown for illustration in  FIG. 1 a   ) are all mutually parallel. Instead of the hydraulic cylinders  50 ,  51  the assembly could optionally use any drive mechanism capable of bidirectional axial movement, for example, any type of mechanical, hydraulic or pneumatic linear actuators e.g. leadscrews or pneumatic cylinders. 
     In this example each of the clamp segments  20   a,    20   b,    30   a  and  30   b  are generally semi-circular (or C-shaped), and are formed e.g. machined or milled from high-strength aluminium, optionally from a single e.g. integral plate of high-strength aluminium, but in other examples the clamp segments can be formed from other materials, or can be formed from discrete components that are fixed together, such as two or more plates separated by intermediate spacer elements which are bolted or otherwise fastened together. 
     Also in this example, as best seen in  FIG. 1  b, clamp segment  30   a  comprises end portions  34   a,    34   b  at opposite distal ends of the clamp segment  30   a,  while clamp segment  30   b  comprises an end portion  35  at one distal end of the clamp segment.  FIG. 1  b shows only the second clamp member  11 , but the skilled reader will understand that the first clamp member has equivalent features not in view in  FIG. 1   b,  particularly end portions  24   a,    24   b  of clamp segment  20   a,  and end portion  25  of clamp segment  20   b.  End portions  24   a,    24   b,    25 ,  34   a,    34   b,    35  of clamp segments  20   a,    20   b,    30   a,    30   b  are adjacent to the semi-circular portions of the clamp segments. Hinges  12   a,    12   b  and swing bolts  14   a,    14   b  are disposed at the end portions of the clamp segments  20   a,    20   b,    30   a,    30   b,  as will be described in more detail below. 
     In this example, the inner surfaces of the clamp segments  20   a,    20   b,    30   a  and  30   b  are symmetrical, arcuate and optionally semi-circular. Thus, when the clamp segments  20   a,    20   b  of clamp member  10 , and the clamp segments  30   a,    30   b  of clamp member  11  are closed, the inner surfaces of the clamp segments  20   a,    20   b  and  30   a,    30   b  optionally have the same radius, and form generally circular apertures in the clamp members  10 ,  11 , which have an inner diameter approximately equal to an outer diameter of a flowline connection  70  (seen in  FIG. 4 ). The centres of the circular apertures of the closed clamp members  10 ,  11  are aligned along an axis that is parallel with the axes of the guide rods  40   a,    40   b,    41   a,    41   b  and hydraulic cylinders  50 ,  51 . 
     As also shown in  FIG. 1   a,  in this example the inner surfaces of clamp segments  20   a,    20   b,    30   a  and  30   b  are recessed, to form grooves or recesses  22 ,  32 , that extend at least partially, or optionally fully, around the arcuate inner surface of the clamp segments. Thus the recesses  22 ,  32  are at least partially annular. In this example the axial separation between the recesses  22 ,  32  is approximately equal to the axial separation between the load shoulders  74   a,    74   b  of flowline connection  70  (seen in  FIG. 4 ), and the radial depth of the recesses  22 ,  32  is approximately equal to or greater than the radial protrusion of the load shoulders  74   a,    74   b  beyond the outer surface of the flowline connection adjacent to the load shoulders. The load shoulders  74   a,    74   b  are thus in this example of a suitable dimension to be received within the recesses  22 ,  32 . 
     In this example a first end portion  24   a  of clamp segment  20   a  is pivotally joined by hinge  12   a  to an end of clamp segment  20   b,  and similarly, a first end portion  34   a  of clamp segment  30   a  is pivotally joined by hinge  12   b  to an end of clamp segment  30   b.    
     The hinges  12   a,    12   b  are generally equivalent. The first end portions  24   a,    34   a  of clamp segments  20   a,    30   a  comprise hinge leaves which extend circumferentially from each semi-circular clamp segment, and which have a reduced width (e.g. in an axial direction) relative to the clamp segments  20   a,    30   a.  Also, the ends of clamps segments  20   b,    30   b  are optionally bifurcated to form a recess whose axial width is approximately equal to the width of the first end portions  24   a,    34   a  of clamp segments  20   a,    30   a.  Apertures are disposed in an axial direction (parallel to the axis of the clamp assembly) through the first end portions  24   a,    34   a  of clamp segments  20   a,    30   a,  and through the ends of clamp segments  20   b,    30   b.  The first end portions  24   a,    34   a  of clamp segments  20   a,    30   a  are positioned within the bifurcations at the ends of clamp segments  20   b,    30   b  such that the apertures through the first end portions  24   a,    34   a  and clamp segments  20   a,    30  are aligned with each other. Pins  13   a,    13   b  are inserted through the aligned apertures, and can be secured in position with secondary fasteners, for example split pins or e-clips. 
     In this example second end portions  24   b,    34   b  of clamp segments  20   a,    30   a  and end portions  25 ,  35  of clamp segments  20   b,    30   b  are also bifurcated. Swing bolts  14   a,    14   b  are pivotally tethered to the second end portions  24   b,    34   b  of clamp segments  20   a,    30   a,  for example by mounting on a pivot pin. Also in this example swing bolts  14   a,    14   b  comprise a threaded shaft or bolt and one or more threaded nuts on the bolt. For example, each swing bolt  14   a,    14   b  may have a first nut for tightening the swing bolt when the first and second clamp members  10 ,  11  are closed, and a second locking nut to secure the position of the first nut after the swing bolts have locked the closed first and second clamp members. Thus the nuts can be loosened to unfasten the swing bolts without completely removing the nut from the shaft of the swing bolt, thereby reducing the risk of dropped objects. 
     As best seen in  FIG. 1 b   , swing bolts  14   a,    14   b  can be rotated around the pivot pins disposed in second end portions  24   b,    34   b  of clamp segments  20   a,    30   a  between a locked position in which the swing bolts are engaged with the end portions  25 ,  35  of clamp segments  20   b,    30   b,  and an unlocked position in which the swing bolts are spaced apart from the end portions  25 ,  35 , and free to rotate around the second end portions  24   b,    34   b  of clamp segments  20   a,    30   a.  When the first and second clamp members  10 ,  11  are closed around flowline connection  70 , the swing bolts  14   a,    14   b  engage with end portions  25 ,  35  to lock together and secure the first and second clamp segments  20   a,    20   b  and  30   a,    30   b  of each clamp member  10 ,  11 . Typically the second end portions  24   b,    34   b  of clamp segments  20 ,  30   a  abut the end portions  25 ,  35  of clamp segments  20   b,    30   b  when the first and second clamp members  10 ,  11  are closed, but the swing bolts  14   a,    14   b  may lock and secure the clamp members even if the end portions  24   b,    34   b  and  25 ,  35  are slightly spaced apart when the clamp members are closed. 
     In this example guide rods  40   a,    40   b  are mounted between clamp segments  20   a  and  30   a,  and guide rods  41   a,    41   b  are mounted between clamp segments  20   b  and  30   b.    
     The guide rods  40   a,    40   b,    41   a,    41   b  are mounted perpendicular to the outer surfaces of clamp members  10 ,  11 , or in other words, perpendicular to the plane of the apertures formed by clamp members  10 ,  11  when they are closed. Also in this example, as best seen in  FIG. 1   b,  the guide rods  40   a,    40   b  and  41   a,    41   b  are mounted symmetrically on clamp segments  20   a,    30   a  and  20   b,    30   b,  and are spaced further from the ends of the semi-circular portions of the clamp segments than from each other. In other words, in this example the guide rods  40   a,    40   b  and  41   a,    41   b  are mounted on semi-circular clamp segments  20   a,    30   a  and  20   b,    30   b  at respective angular positions of approximately 60 degrees and 120 degrees around the arc of the clamp segments. In other examples, particularly where there are fewer than or more than two guide rods per pair of clamp segments, the guide rods need not be regularly or symmetrically spaced. 
     Optionally a first axial end of each of the guide rods  40   a,    40   b  and  41   a,    41   b  is rigidly fixed to respective clamp segments  20   a,    20   b  of the first clamp member  10 . For example, bolts can be passed through a side surface of clamp segments  20   a,    20   b  to engage with a coaxial threaded bore of the guide rods, which are then tightened to fix the guide rods to the opposing side surface of the clamp segments  20   a,    20   b.    
     The second axial end of each of the guide rods  40   a,    40   b  and  41   a,    41   b  is moveably (e.g. slidably) connected to respective clamp segments  30   a  and  30   b  of the second clamp member  11 . In this example guide rods  40   a,    40   b  and  41   a,    41   b  extend through bores  36  (shown in  FIG. 1 b   ) through the side surfaces of respective clamp segments  30   a  and  30   b.  Also in this example, ball bearings  38  (e.g. linear ball bearings) are optionally disposed within the bores  36 , which allow the guide rods  40   a,    40   b  and  41   a,    41   b  to slide axially through the clamp segments  30   a  and  30   b,  but restrict the guide rods from significant deviation from a perpendicular orientation with respect to the clamp segments. In other words, the linear ball bearings  38  maintain the axes of the guide rods  40   a,    40   b  and  41   a,    41   b  in parallel alignment with the direction of axial movement of the first clamp member  10  relative to the second clamp member  11 . In this example each linear ball bearing  38  also comprises a collar with an aperture  39  (best seen in  FIG. 2 a   ) adjacent the side surfaces of clamp segments  30   a,    30   b  facing clamp segments  20   a,    20   b.    
     Also in this example, an indicator in the form of a score or groove  44  (best seen in 
       FIGS. 1 a    and  FIG. 6 b   ) is provided on an outer surface of each of the guide rods  40   a,    40   b,    41   a,    41   b.  The indicator grooves  44  optionally extend circumferentially around each of the guide rods. The indicator grooves  44  are positioned axially on the guide rods so that when the first and second clamp members  10 ,  11  are in the axially retracted position, or in other words when the axial spacing between first and second clamp members corresponds to the axial spacing between load shoulders  74   a,    74   b  of flowline connection  70 , the indicator grooves  44  align with the collars of linear ball bearings  38 . Thus, the first and second clamp members  10 ,  11  are correctly positioned to engage with the flowline connection  70  when the indicator grooves  44  are immediately adjacent to (e.g. just visible beside) the collars of linear ball bearings  38 . 
     In this example, apertures  46  (best seen in  FIG. 3 b   ) extend diametrically (e.g. perpendicular to the axis) through each of the guide rods  40   a,    40   b,    41   a,    41   b.  The apertures  46  are positioned axially on the guide rods so that when the first and second clamp members  10 ,  11  are in the axially expanded position, the apertures  46  align with the apertures  39  through the collars of linear ball bearings  38 . 
     In this example a first hydraulic cylinder  50  is mounted between clamp segments  20   a  and  30   a,  and a second hydraulic cylinder  51  is mounted between clamp segments  20   b  and  30   b.  The hydraulic cylinders  50 ,  51  are mounted parallel to the guide rods  40   a,    40   b,    41   a,    41   b,  and in this example are disposed intermediate the guide rods connecting respective clamp segments  20   a,    30   a  and  20   b,    30   b.  Optionally the axial ends of each of the hydraulic cylinders  50 ,  51  are rigidly fixed to respective clamp segments  20   a,    20   b  of the first clamp member  10  and clamp segments  30   a,    30   b  of the second clamp member  11 , adjacent to the outer surfaces of the clamp segments  20   a,    20   b  and  30   a,    30   b.  In this example, the cylinders  52 ,  53  of hydraulic cylinders  50 ,  51  are joined to the clamp segments  20   a,    20   b  of the first clamp member  10 , and the pistons  54 ,  55  are joined to the clamp segments  20   b,    30   b  of the second clamp member  11 . Alternatively, the cylinders  50 ,  51  could be in the opposite orientation. 
     As best seen in  FIG. 2 b   , in this example both hydraulic cylinders  50 ,  51  share a common ‘push’ stroke line  56  and a common ‘pull’ stroke line  57 , each in a direction parallel with the axes of the guide rods  40   a,b  and  41   a,b.  Typically the ‘push’ and ‘pull’ stroke lines supply pressurised hydraulic fluid from a single source (e.g. 
     reservoir) to different hydraulic chambers within the hydraulic cylinders  50 ,  51 . For example, the ‘push’ stroke line supplies pressurised hydraulic fluid to corresponding first chambers of hydraulic cylinders  50 ,  51  to extend the pistons  54 ,  55  and move the clamp members  10 ,  11  toward their axially expanded position, and the ‘pull’ stroke line supplies pressurised hydraulic fluid to corresponding second chambers of hydraulic cylinders  50 ,  51  to retract the pistons  54 ,  55  and move the clamp members  10 ,  11  toward their axially retracted position. 
     A bearing removal tool  60  is shown in  FIGS. 5 a    and  5   b.  As will be explained in more detail below, after the clamp assembly  1  has been operated in order to separate the flowline connection  70  and provide access to the bearing ring  76  and/or seals  78   a,    78   b  (seen in  FIG. 4 ), for example for routine maintenance or replacement, the bearing ring can be difficult to remove from the end of a flowline section  72   a,    72   b  after the ends of the flowline sections have been separated. The bearing removal tool  60  allows the bearing ring  76  to be removed from the end of flowline section  72   a  or  72   b.    
     In this example the bearing removal tool  60  comprises two cam arms  62   a,    62   b  which are interconnected by a handle  63 . The cam arms  62   a,    62   b  are generally similar to each other and are orientated in the same direction as each other. The handle  63  is disposed perpendicular to the cam arms  62   a,    62   b,  and is rigidly fixed to the cam arms at a first distal end of the cam arms. The opposing second distal end of each of the cam arms  62   a,    62  comprises a first cam surface  64   a,    64   b  and a second cam surface  65   a,    65   b.  Pivot points  66   a,    66   b  are disposed on the cam arms  62   a,    62   b  adjacent to the first and second cam surfaces  64   a,    64   b,    65   a,    65   b.    
     Cam surfaces  64   a,    64   b  and  65   a,    65   b  are defined by their changing (e.g. increasing) distance or radius from pivot points  66   a,    66   b.  As best seen in  FIG. 5 b   , in this example the radius of first cam surfaces  64   a,    64   b  from pivot points  66   a,    66   b  increases gradually around the first cam surfaces, and the radius of second cam surfaces  65   a,    65   b  increases and then decreases relatively sharply around the second cam surfaces. Also in this example, the maximum radius of the first cam surfaces  64   a,    64   b  is less than the maximum radius of the second cam surfaces  65   a ,  65   b.    
     Also in this example the bearing removal tool  60  further comprises a drive arm  68 . The distal ends of the drive arm  68  are pivotally connected to the cam arms  62   a,    62   b  at pivot points  66   a,    66   b,  such that the cam arms can rotate relative to the drive arm. In this example an inner portion of the drive arm  68  is semi-circular, with an inner diameter that is slightly larger than the outer diameter of the outer surface of bearing ring  76 , but slightly smaller than the outer diameter of a shoulder or lip  77  disposed on the outer surface of the bearing ring  76 . The end portions of the drive arm  68  which are pivotally connected to cam arms  62   a,    62   b  are straight, and are orientated perpendicular to the plane of the notional circle forming the semi-circular inner portion of the drive arm. Optionally a secondary handle  69  is fixed to the semi-circular inner portion of the drive arm  68 , approximately midway around the arc of the semi-circular inner portion. 
     In operation, the hydraulic cylinders  50 ,  51  of the clamp assembly  1  are first activated to move the clamp members  10 ,  11  into their axially retracted position, in which the second clamp member  11  is aligned with the indicator grooves  44  of the guide rods  40   a,    40   b,    41   a,    41   b,  as illustrated in  FIGS. 2 a  and 2 b   . In this position, the clamp members  10 ,  11  are axially separated by a distance equivalent to the axial separation of the load shoulders  74   a,    74   b  of flowline connection  70  (when made up), and so the recesses  22 ,  32  of the clamp segments  20   a,    20   b,    30   a,    30   b  will engage with the load shoulders  74   a,    74   b  when the clamp members  10 ,  11  are closed around the flowline. 
     The clamp assembly  1  is then manoeuvred into position above the flowline connection  70  by supporting (e.g. suspending) the clamp assembly from lifting eyes  18  with a suitable hoisting or lifting device, such as a crane or forklift. Typically the clamp assembly  1  is manoeuvred to a point vertically above the flowline connection  70 , and rotated horizontally so that the clamp members  10 ,  11  are approximately aligned with the load shoulders  74   a,    74   b  of the flowline connection. 
     The clamp members  10 ,  11  of the clamp assembly  1  are then opened, for example by manually pulling the end portions  24   b,    34   b  of first clamp segments  20   a,    30   a  away from the end portions  25 ,  35  of second clamp segments  20   b,    30   b.  In this example the end portions  24   b,    34   b  can be separated from the end portions  25 ,  35  by at least 15 inches (0.381 metres) when the clamp members  10 ,  11  are opened (e.g. before being lowered onto the flowline connection  70 ), and optionally can be separated by up to about 26 inches (0.660 metres), depending on the extent of relative rotation between the first and second clamp segments  20   a,    20   b  and  30   a,    30   b,  but in other examples the distances between the separated end portions  24   b,    34   b,  and  25 ,  35  may be smaller or greater than this, for example to accommodate flowline connections having smaller or greater maximum outer diameters. Typically the lifting eyes  18  are positioned on the first and second clamp segments  20   a,    20   b,    30   a,    30   b  a suitable distance away from pivots  12   a,    12   b  e.g. approximately aligned with the first guide rods  40   a,    41   a  to ensure that the weight of the clamp assembly  1  does not strongly urge the clamp members  10 ,  11  toward the open or closed position. In this example the lifting eyes  18  are positioned a suitable distance from pivots  12   a,    12   b  to provide the clamp members  10 ,  11  with a slight bias toward the closed position. Alternatively in this example, the clamp assembly  1  can be suspended from lifting eyes  18  of the first clamp segments  20   a,    30   a,  and from auxiliary lifting eyes  19  of the second clamp segments  20   b,    30   b  (or vice versa), which optionally provides the clamp members  10 ,  11  with a slight bias toward the open position, which can allow the clamp assembly  1  to be more easily lowered onto the flowline connection  70 . In this case, the clamp members  10 ,  11  are typically closed manually around the flowline connection  70  once the clamp assembly  1  is in position around the flowline connection. 
     The clamp assembly  1  is then lowered onto the flowline connection  70  so that the first clamp segments  20   a,    30   a  pass down one side of the flowline connection, and the second clamp segments  20   b,    30   b  pass down the other side of the flowline connection. 
     The clamp members  10 ,  11  are then closed around the flowline connection  70 , for example by pushing the end portions  24   b,    34   b  of first clamp segments  20   a,    30   a  toward the end portions  25 ,  35  of second clamp segments  20   b,    30   b,  or the clamp members  10 ,  11  may optionally be sufficiently biased to move toward the closed position without intervention. As the clamp members  10 ,  11  are closed, the recesses  22 ,  32  of the clamp segments  20   a,    20   b,    30   a,    30   b  engage with the load shoulders  74   a,    74   b  of the flowline connection  70 . The swing bolts  14   a,    14   b  are then rotated from their unlocked positions to their locked positions in which they are engaged with the end portions  25 ,  35  of second clamp segments  20   b,    30   b,  and in this example, the bolts of the swing bolts  14   a,    14   b  are partially tightened (e.g. hand tightened) to hold the clamp members  10 ,  11  in their closed positions, while allowing rotation of the clamp assembly  1  around the flowline connection  70 . 
     Prior to separating the flowline connection  70 , a locking clamp  71  around the flowline connection is first removed to allow the flowline sections  72   a,    72   b  of the flowline to be moved apart from each other. Typically the locking clamp  71  comprises a cylinder-shaped body that can be radially removed from the flowline connection  70  as two equal half segments  71   a,    71   b  from either side of the flowline connection, in opposing directions. To facilitate this, the clamp assembly  1  can be rotated a quarter turn (e.g. about 90 degrees) around the flowline connection  70 , from the orientation shown in  FIG. 2 a    to the orientation shown in  FIG. 2 b   . After fully tightening the swing bolts  14   a,    14   b  to secure the flowline connection  70  within the clamp assembly  1 , the segments  71   a,    71   b  of the locking clamp  71  can be loosened and disconnected, and then radially removed in a horizontal direction from the flowline connection  70 , between the guide rods of opposing clamp segments e.g. between the guides rods  40   a,    41   a  on one side of the flowline connection, and between the guide rods  40   b,    41   b  on the other side of the flowline connection. 
     After the locking clamp  71  has been removed from the flowline connection  70 , the hydraulic cylinders  50 ,  51  can be activated to extend the pistons  54 ,  55 , thereby moving the clamp members  10 ,  11  into their axially expanded position in a direction parallel to the axes of the guide rods  40   a,b  and  41   a,b,  best seen in  FIG. 6 b   . As the clamp members  10 ,  11  move apart, the load shoulders  74   a  of the first flowline section  72   a  are urged apart from the load shoulders  74   b  of the second flowline section  72   b,  thus separating the flowline sections  72   a,    72   b  apart from each other. The axes of the two flowline sections  72   a,    72   b  are maintained in alignment during the axial separation by the guide rods and the drive mechanism. Once the flowline connection  70  has been separated, but before any work is carried out on any of the internal components of the flowline connection, locking pins  16  are inserted through the aligned apertures  39 ,  46  of the collars of the linear ball bearings  38  and of the guide rods  40   a,    40   b,    41   a,    41   b.  The locking pins  16  restrict movement of the guide rods  40   a,    40   b,    41   a,    41   b  relative to the second clamp member  11 , and thus prevent any significant axial movement of the first and second clamp members  10 ,  11  relative to each other. 
     Once the locking pins  16  are in place, the internal components of the flowline connection  70  can be safely accessed. The inner surfaces of the bearing ring  76  typically form a partial seal with flowline sections  72   a,    72   b  (in addition to the seals formed by seal rings  78   a,    78   b ), which results in the creation of a partial vacuum between the axial ends of flowline sections  72   a,    72   b  and the axially-facing surfaces of the bearing ring, which can be difficult to overcome when separating the flowline connection  70 . Typically when the clamp assembly  1  separates the flowline connection  70 , the bearing ring  76  is removed from the flowline section  72   a  or  72   b  to which it adheres least, but remains attached to the flowline section  72   a  or  72   b  to which it adheres more strongly. 
     To remove the bearing ring  76  from the flowline section  72   a  or  72   b,  the bearing removal tool  60  is first inserted into the flowline connection, so that the drive arm  68  engages with the lip  77  of the bearing ring  76 , and the first cam surfaces  64   a,    64   b  engage with the side surfaces of clamp segments  20   a,    20   b,  as shown in  FIG. 6 a   . Note that if the bearing ring  76  had remained attached to the first flowline section  72   a  rather than the second flowline section  72   b  as shown in  FIG. 6 a   , the first cam surfaces  64   a,    64   b  of the bearing removal tool  60  could alternatively be engaged with the side surfaces of the clamp segments  30   a,    30   b.    
     The bearing removal tool  60  is then operated by applying a force, e.g. in an axial direction, typically by hand, to the handle  63  of the bearing removal tool  60 , while supporting the position of the drive arm  68  against the lip  77  of the bearing ring  76  with the secondary handle  69 . As the handle  63  is pulled in an axial direction away from the clamp segments  20   a,    20   b  with which the first cam surfaces  64   a,    64   b  are engaged, the first cam surfaces rotate against clamp segments  20   a,    20   b  and urge the pivot points  66   a,    66   b  axially away from the clamp segments  20   a,    20   b,  which also drives the drive arm  68  axially away from the clamp segments  20   a,    20   b.  Thus, the drive arm  68  begins to drive the bearing ring  76  away from the end of flowline section  72   a.  As best seen in  FIG. 5 b   , because the radius of first cam surfaces  64   a,    64   b  increases only gradually, a relatively large movement of handle  63  causes only a relatively small movement of pivot points  66   a,    66   b,  but this small movement provides a correspondingly large mechanical advantage that is able to overcome the partial vacuum seal of the bearing ring  76  with the flowline section  72   a.  As the handle  63  is pulled further, second cam surfaces  65   a,    65   b  make contact with clamp segments  20   a,    20   b,  which lifts first cam surfaces  64   a,    64   b  away from clamp segments  20   a,    20   b,  as also illustrated in  FIG. 5 b   . In this example, as best seen in  FIG. 5 b   , the minimum radius of the second cam surfaces  65   a,    65   b  is greater than the maximum radius of the first cam surfaces  64   a,    64   b.  Therefore, after the second cam surfaces  65   a,    65   b  have engaged the clamp segments  20   a,    20   b,  further movement of handle  63  causes a relatively large movement of pivot points  66   a,    66   b  axially away from the clamp segments  20   a,    20   b,  but with a correspondingly smaller mechanical advantage. This allows the bearing removal tool  60  to completely remove the bearing ring  76  from the flowline section  72   a  by causing axial movement of the drive arm  68  that is equal to or greater than the axial length of the portion of flowline section  72   a  on which the bearing ring  76  was mounted. Once the bearing ring  76  has been moved off the flowline section  72   a,  it can be removed from the clamp assembly  1 , for example by withdrawing it radially from the flowline connection  70  between guide rods  40   a,    41   a.    
     The procedure for replacing the bearing ring  76  and/or seals  78   a,    78   b,  and re-making the flowline connection  70 , is generally the reverse of the procedure for separating the flowline connection and removing the bearing ring  76  described previously. Referring again to  FIG. 6 a   , the bearing ring  76  can be loosely mounted (e.g. by hand) on the end of either of flowline sections  72   a  or  72   b.  Preferably, the bearing ring  76  is checked to ensure that it is square with the flowline section (e.g. that the axis of the bearing ring  76  is coaxial with the axis of the flowline section  72   a  or  72   b ). 
     Before activating the hydraulic cylinders  50 ,  51  to retract the pistons  54 ,  55  and return the clamp members  10 ,  11  to their axially retracted position seen in  FIGS. 2 a  and 2 b   , the locking pins  16  must first be removed from the guide rods  40   a,    40   b,    41   a,    41   b,  to allow the guide rods to move axially relative to the second clamp member  11 . The hydraulic cylinders  50 ,  51  can then be activated, and clamp members  10 ,  11  begin to approach each other, in a direction parallel to the axes of the guide rods  40   a,b  and  41   a,b.  As the clamp members  10 ,  11  move together, the load shoulders  74   a  of the first flowline section  72   a  are urged toward the load shoulders  74   b  of the second flowline section  72   b,  and the ends of flowline sections  72   a,    72   b  are received into the ends of the bearing ring  76 . The hydraulic cylinders  50 ,  51  deliver sufficient axial compression force to the clamp members  10 ,  11  to drive home the flowline sections  72   a,    72   b  within the bearing ring  76  and engage the seals  78   a,    78   b.    
     Once the flowline connection  70  has been re-made, the locking clamp  71  is also replaced around the flowline connection, for example by returning the half segments of the locking clamp to the flowline connection and then reconnecting and tightening them together. The swing bolts  14   a,    14   b  can then be partially loosened to allow the clamp assembly  1  to be rotated around the flowline connection  70  to its original position shown in  FIG. 2 a    e.g. with the swing bolts  14   a,    14   b  vertically below the flowline connection  70 . The swing bolts  14   a,    14   b  can then be fully loosened and moved toward the unlocked positions, thus releasing the end portions  25 ,  35  of second clamp segments  20   b,    30   b  from the end portions  24   b,    34   b  of first clamp segments  20   a,    30   a.    
     Finally, the clamp assembly  1  is re-attached to the hoisting or lifting device in order to at least partially support the clamp assembly while the clamp members  10 ,  11  are again opened, for example by manually pulling the end portions  24   b,    34   b  of first clamp segments  20   a,    30   a  away from the end portions  25 ,  35  of second clamp segments  20   b,    30   b.  Once the first and second clamp segments  20   a,    20   b  and  30   a,    30   b  have been rotated relative to each away from the pipeline connection  70 , the clamp assembly  1  can be lifted above and away from the flowline connection. 
     A second example of a clamp assembly  101  in accordance with one or more embodiments is shown in  FIGS. 7 a  to 7 l   . The second example is generally similar to the first example described above, and equivalent parts are numbered similarly, but the reference numbers are increased by 100. In the second example, the clamp members  110 ,  111  (including hinges  112   a,    112   b  (seen in  FIG. 7 b   ) and swing bolts  114   a,    114   b ), guide rods  140   a,    140   b,    141   a,    141   b  and hydraulic cylinders  150 ,  151  are all similar in form and function to the equivalent parts of the first example described above. 
     In this example, as seen in  FIG. 7 a   , first and second optional clamp removal gantries  126   a,    126   b  are connected respectively to clamp segments  120   a,    120   b  of the first clamp member  110 . Rail guides  121   a,    121   b  are disposed on side surfaces of clamp segments  120   a,    120   b,  generally diagonally opposite one another, approximately adjacent to the rigidly fixed ends of guide rods  140   a  and  141   b.  Rails  123   a,    123   b  are slidable through the rail guides  121   a,    121   b,  and clamp brackets  128   a,    128   b  are pivotally connected to a first distal end of each rail  123   a,    123   b.    
     As first seen in  FIG. 7 d   , the clamp brackets  128   a,    128   b  are adapted to be attached to clamp segments  171   a,    171   b  of the locking clamp which secures flowline connection  170 . The locking clamp and clamp segments  171   a,    171   b  in this example are equivalent to the locking clamp  71  and clamp segments  71   a,    71   b  described above in the first example. In this example the clamp brackets  128   a,    128   b  comprise two parallel plates which are joined by one or more handles, and a connection plate  129   a,    129   b  ( 129   b  seen in  FIG. 7 e   ). Also in this example, an aperture is disposed through each of the connection plates  129   a,    129   b,  through which a fixing such as a bolt can be passed to secure the clamp segments  171   a,    171   b  to the clamp brackets  128   a,    128   b.    
     In this example the rail guides  121   a,    121   b  are adapted to allow the rails  123   a,    123   b  to slide bidirectionally through the rail guides. The rails  123   a,    123   b  optionally slide in a direction perpendicular to the axes of the guide rods  140   a,    140   b,    141   a,    141   b,  and optionally generally parallel to an axis which passes through the respective ends of the clamp segments  120   a,    120   b.  In other words, rail  123   a  slides parallel to an axis joining the end portions  124   a,    124   b  of clamp segment  120   a,  and rail  123   b  slides parallel to an axis joining the end portion  125  and opposing end of clamp segment  120   b.  Optionally the rails  123   a  and  123   b  are mutually parallel when the clamp segments are closed. Each clamp removal gantry  126   a,    126   b  optionally has a stowed position, in which the clamp brackets  128   a,    128   b  have least separation from the rail guides  121   a,    121   b  and each rail  123   a,    123   b  is positioned generally alongside the side surfaces of clamp segments  120   a,    120   b,  as best seen in  FIG. 7 b   . Each clamp removal gantry  126   a,    126   b  optionally also has an extended position, in which the clamp brackets  128   a,    128   b  have greatest separation from the rail guides  121   a,    121   b  and each rail  123   a,    123   b  is moved radially away from the generally circular aperture formed by the inner surfaces of the clamp members  120   a,    120   b,  as best seen in  FIGS. 7 d  and 7 e   . Also in this example, the opposing second end of each rail  123   a,    123   b  from the clamp bracket  128   a,    128   b  optionally incorporates a stop which prevents each rail  123   a,    123  from sliding beyond the extended position seen in  FIGS. 7 d  and 7 e    and out of the rail guides  121   a,    121   b.  Optionally, each rail guide  121   a,    121   b  also comprises a rail brake, which can be engaged e.g. by tightening to restrict the sliding movement of each rail  123   a,    123   b  relative to the corresponding rail guide  121   a,    121   b.    
     In this example the clamp brackets  128   a,    128   b  are connected to the first distal ends of the rails  123   a,    123   b  by pivot connections or hinges  127   a,    127   b  which allow the clamp brackets to rotate about approximately 180 degrees around the ends of the rails, best seen by comparing  FIGS. 7 d  and 7 e    (although other ranges of motion are possible). The clamp brackets  128   a,    128   b  rotate in a plane that is parallel with the rails  123   a,    123   b,  and perpendicular to the plane of the circular aperture of the first clamp member  110 , typically around a pivot axis that is perpendicular to the axes of the guide rods  140   a,b  and  141   a,b.  Optionally each clamp bracket hinge  127   a,    127   b  incorporates a locking pin which can be inserted into each hinge to lock the position e.g. rotational position of each clamp bracket  128   a,    128   b  relative to the rails  123   a,    123   b.    
     The operation of the clamp assembly  101  is generally similar to the operation of the first example of the clamp assembly  1  described above, except that in this example, the clamp removal gantries  126   a,    126  assist in the removal of the clamp segments  171   a,    171   b  of the locking clamp before the flowline connection  170  is separated, and when replacing the clamp segments  171   a,    171   b  of the locking clamp after the flowline connection is remade. 
     While the clamp assembly  101  is supported (e.g. suspended) from a hoisting or lifting device, the clamp members  110 ,  111  are opened, for example by manually pulling end portions  124   b,    134   b  of first clamp segments  120   a,    130   a  away from end portions  125 ,  135  of second clamp segments  120   b,    130   b,  as seen in  FIG. 7 a   . The clamp assembly  101  is then lowered onto the flowline connection  170 , the clamp members  110 ,  111  are closed around the flowline connection  170 , and the swing bolts  114   a,    114  are fully tightened after rotating the clamp assembly  101  a quarter turn around the flowline connection  170  into the position shown in  FIG. 7 b   . The rail brakes in the rail guides  121   a,    121   b  are disengaged and the locking pins removed from the clamp bracket hinges  127   a,    127   b  (clamp hinge  127   b  only visible in  FIG. 7 a   ) to allow the clamp brackets  128   a,    128   b  to be rotated around the pivot connections with the rails  123   a,    123   b,  such that the connection plates  129   a,    129   b  are now facing the flowline connection  170 . The locking pins are then replaced in the clamp bracket hinges  127   a,    127   b  to lock the clamp brackets  128   a,    128   b  in position. 
     The clamp brackets  128   a,    128   b  are then moved toward the clamp segments  171   a,    171   b  by sliding the rails  123   a,    123   b  toward their engaged position, seen in  FIG. 7 c   . The positions of the clamp brackets  128   a,    128   b  are adjusted until the connection plates of the clamp brackets  128   a,    128   b  contact the clamp segments  171   a,    171   b,  and bolts are inserted through the connection plates into the clamp segments to secure the clamp segments to the clamp brackets  128   a,    128   b.  The rail brakes in the rail guides  121   a,    121   b  are then re-engaged to ensure that any movement of the clamp brackets  128   a,    128   b  relative to the flowline connection  170  is substantially restricted. 
     The fixings (typically bolts) between the clamp segments  171   a,    171   b  can then be removed, releasing the clamp segments from each other and from the flowline, although the clamp segments typically remain substantially stationary while the rail brakes in the rail guides  121   a,    121   b  are engaged. When the rail brakes are disengaged, the rails  123   a,    123   b  and clamp brackets  128   a,    128   b  can be moved partially or fully toward their extended position, shown in  FIG. 7 d   , before the rail brakes are again engaged. The clamp segments  171   a,    171   b  are thus removed from the flowline connection  170 . In order to provide improved access to the flowline connection between the guide rods on either side of the flowline connection, the clamp brackets  128   a,    128   b  and attached clamp segments  171   a,    171   b  can then optionally be rotated by removing the locking pins from the clamp bracket hinges  127   a,    127   b,  rotating the clamp brackets, and replacing the locking pins. The rails  123   a,    123   b  and clamp brackets  128   a,    128   b  with attached clamp segments  171   a,    171   b  can also optionally be returned to their stowed positions as shown in  FIG. 7 e    if a large unobstructed working area is required around the flowline connection  170  by releasing the rail brakes in the rail guides  121   a,    121   b,  returning the rails  123   a,    123   b  to their stowed positions and then optionally re-engaging the rail brakes. 
     The flowline connection  170  can then be separated by actuating the hydraulic cylinders  150 ,  151 , expanding the clamp assembly  101  and inserting the locking pins  116  in the same manner as previously described for the first example of a clamp assembly  1 , as shown in  FIG. 7   f.    
     Use of a bearing removal tool  160  to remove the bearing ring  176  in the same manner described above in the first example is illustrated in  FIGS. 7 g  and 7 h   . The bearing removal tool is shown inserted into the flowline connection  170  as shown in  FIG. 7 g    to engage with the bearing ring  176 , and then a force is applied e.g. in a direction generally parallel to the axes of the guide rods  140   a,b  and  141   a,b  to move the bearing removal tool  160  into the position shown in  FIG. 7 h   , which as described previously, frees the bearing ring  176  from the flowline connection. The bearing ring  176  and or seals (shown only in  FIG. 4  as  78   a ,  78   b ) can then be maintained or replaced as required. 
     The procedure for re-making the flowline connection  170  and returning the clamp segments  171   a,    171   b  to the flowline connection after the connection has been re-made is generally the reverse of the procedure for removing the clamp segments and breaking the flowline connection described above. As shown in  FIG. 7 i   , after maintenance operations on the bearing and seal etc. in the flowline are complete, the locking pins  116  are removed from the guide rods  140   a,    140   b,    141   a,    141   b,  and the hydraulic cylinders  150 ,  151  then activated to drive the clamp members  110 ,  111  toward each other, as shown in  FIG. 7   j.    
     The rail brakes in the rail guides  121   a,    121   b  and the locking pins of the clamp bracket hinges  127   a,    127   b  are then released and or removed as required in order to manoeuvre the clamp brackets  128   a,    128   b  and attached clamp segments  171   a,    171   b  back into the engaged position around the flowline connection  170 , as illustrated in  FIG. 7 k   . As with removing the clamp segments  171   a,    171   b,  the rail brakes are engaged when initially re-joining the clamp segments to each other, but it is useful if the rail brakes in the rail guides  121   a,    121   b  are released prior to fully tightening the fixings e.g. bolts between the clamp segments  171   a,    171   b,  to ensure that the clamp segments are free to move relative to each other while being fully tightened. Once the locking clamp  170  is again secured around the flowline connection, the connection plates of the clamp brackets  128   a,    128   b  are released from the clamp segments  171   a,    171   b,  and the clamp removal gantries  126   a,    126   b  are again returned to their stowed positions as seen in  FIG. 7   b.    
     Finally, the swing bolts  114   a,    114   b  can be partially loosened to allow the clamp assembly  101  to be rotated around the flowline connection  170 , and then the swing bolts fully loosened and moved toward their unlocked positions, thus releasing the end portions  125 ,  135  of second clamp segments  120   b,    130   b  from the end portions  124   b,    134   b  of first clamp segments  120   a,    130   a.  The clamp assembly  101  can then be re-attached to the hoisting or lifting device, and the clamp assembly  101  lifted above and away from the flowline connection  170 , as shown in  FIG. 7 l   . In one possible modification, the recesses of the assembly  101  shown in  FIGS. 7 a -7 l    could have multiple slots, e.g. 2, 3, 4 or more slots, arranged to receive multiple ridges of each of the load shoulders attached to the pipe. A similar modification could be made to the assembly  1  shown in the earlier figures.