Modular pipeline clamp

Abstract

Pipeline clamp for connecting to a subsea pipeline, the connector comprising: Two hemicylindrical portions, first comprising clamps 3-1 and 3-2, while the second comprises clamps 3-3 and (3-4), where

Description

Field of the Invention The present invention relates to pipeline connectors / clamps and to a modular pipeline clamp comprising a plurality of constituent connectors / clamps. The invention is particularly suitable, but by no means limited, for use during the repair / replacement of portions of subsea pipelines. Background to the Invention Subsea pipelines are pipelines which are used to convey fluids (such as oil or gas) between two locations. In some instances, such pipelines are used to convey fluids from an offshore extraction facility (e.g. an offshore oil platform) to the shore for further processing of the extracted fluid. These pipelines are sometimes referred to as export pipelines. Similarly, pipelines are sometimes used to connect between offshore facilities, and in this case these pipelines are sometimes referred to as in-field pipelines. Over time, defects may arise in subsea pipelines, such as leaks, cracks and general corrosion associated with long-term use in challenging subsea conditions. Additionally, ruptures may occur along a section of pipeline e.g. in the event of a process faults or an earthquake. Moreover, dents, gouges and buckles may be caused along portions of a subsea pipeline by anchors and / or fishing apparatus being dragged over the pipeline. Such defects may be detected during routine subsea maintenance (e.g. by divers, by remotely operated vehicles (ROVs), and / or by sensors). Given the myriad of ways in which pipelines can be damaged, as well as given the potential for ecological issues and for downtime, many pipeline operators maintain a large stock of various sizes of pipeline clamps, connectors and couplings to repair the defective pipeline as quickly as possible. This necessitates each operator to carry a large inventory of such repair devices, both on shore as well as at sea, as well as having a certain degree of luck insofar as the repair device that they have in stock will actually be able to fit to and fix the defective pipeline. Should a particularly problematic defect be found in a pipeline and the stocked repair devices be unable to repair the defect, the operator will instead need to obtain a bespoke repair device to repair the defective pipeline. It can take more than six months for such a device to be manufactured and shipped to the site for repairing the defective pipeline, potentially causing a great deal of loss for the pipeline operator during the period of downtime in oil and gas production. There is therefore a desire for pipeline clamp apparatus which addresses at least some of the above problems. Summary of the Invention The present invention is set out in the appended independent claims. Optional features are set out in the appended dependent claims. Disclosed is a pipeline clamp for connecting to a subsea pipeline, the pipeline connector comprising: a first hemicylindrical portion comprising first and second clamping means, a second hemicylindrical portion comprising third and fourth clamping means, wherein the first and third clamping means and the second and fourth clamping means are configured for mutual alignment; wherein each of the first and second hemicylindrical portions comprises first and second ends, each of the first and second ends having a sealing region for sealing the pipeline in use, and defining a void between the sealing region of the first end and the sealing region of the second end; and wherein at least one of the first and second hemicylindrical portions further comprises an inlet, in communication with the void, for receiving a filler. Optionally, each sealing region may comprise an internal plurality of grooves for sealing the subsea pipeline in use. Optionally, the first and third clamping means may be hingedly connected. Optionally, at least one of the first and second ends of the first and second hemicylindrical portions may comprise an external coupling portion for receiving a coupling member for coupling the pipeline clamp to another pipeline clamp. Optionally, each of the first and second hemicylindrical portions may comprise one or more locating means, disposed about a respective external perimeter of each of the first and second hemicylindrical portions, for mutually aligning the pipeline clamp with another pipeline clamp. Optionally, each of the locating means may comprise an eyelet protruding from the respective hemicylindrical portion for receiving a tie rod in use. Optionally, each of the locating means may comprise two or more eyelets mutually aligned along a longitudinal axis for receiving the tie rod in use. Also disclosed is a modular pipeline clamp comprising a plurality of pipeline clamps as described above, and one or more coupling members for coupling the pipeline clamps, wherein each coupling member is configured to interpose between adjacent pipeline clamps and to engage with the external coupling portion of each of the adjacent pipeline clamps. Optionally, the modular pipeline clamp may further comprise a plurality of tie rods configured to pass through mutually longitudinally aligned eyelets, wherein at least one end of each tie rod comprises a thread for receiving a fastener to secure each tie rod between the longitudinally aligned eyelets of the connected pipeline clamps. Also disclosed is a pipeline clamp for connecting to a subsea pipeline, the pipeline clamp comprising: a first hemicylindrical portion comprising first and second clamping means; a second hemicylindrical portion comprising third and fourth clamping means, wherein the first and third clamping means and the second and fourth clamping means are configured for mutual alignment; wherein each of the first and second hemicylindrical portions comprises first and second ends, each of the first ends having a sealing region for sealing the pipeline in use; and wherein each of the second ends comprises an annular rim having an adjustable grip configured for adjustment by one or more bolts. Optionally, the sealing region may comprise an internal plurality of grooves for sealing the subsea pipeline in use and the adjustable grip may be a pipeline gripping system comprising rows of gripping balls and / or gripping wedges which may be adjustable by the one or more bolts for gripping the pipeline in use. Optionally, the first and third clamping means may be hingedly connected. Optionally, each of the first ends of the first and second hemicylindrical portions may comprise an external coupling portion for receiving a coupling member for coupling the pipeline clamp to another pipeline clamp. Optionally, each of the first and second hemicylindrical portions may comprise one or more locating means, disposed about a respective external perimeter of each of the first and second hemicylindrical portions, for mutually aligning the pipeline clamp with another pipeline clamp. Optionally, each of the locating means may comprise an eyelet protruding from the respective hemicylindrical portion for receiving a tie rod in use. Optionally, each of the locating means may comprise two or more eyelets mutually aligned along a longitudinal axis for receiving the tie rod in use. Optionally, the first and second hemicylindrical portions may be connected by an actuatable piston for controlling the rate at which the first and second portions are brought together in use. Also disclosed is a modular pipeline clamp comprising two pipeline clamps as describe above; and a coupling member for coupling the pipeline clamps, wherein the coupling member is configured to interpose between each pipeline clamp and to engage with the external coupling portion of each pipeline clamp. Optionally, the modular pipeline clamp may further comprise a plurality of tie rods configured to pass through mutually longitudinally aligned eyelets, wherein at least one end of each tie rod comprises a thread for receiving a fastener to secure each tie rod between the longitudinally aligned eyelets of the connected pipeline clamps. Also disclosed is a modular pipeline clamp, comprising: at least one of first pipeline clamp; at least two different pipeline clamps, and a plurality of coupling members for coupling the pipeline clamps, wherein each coupling member is configured to interpose between adjacent pipeline clamps and to engage with the external coupling portion of each of the adjacent pipeline clamps. Optionally, the modular pipeline clamp may further comprise a plurality of tie rods configured to pass through mutually longitudinally aligned eyelets, wherein at least one end of each tie rod comprises a thread for receiving a fastener to secure each tie rod between the longitudinally aligned eyelets of the connected pipeline clamps. Also disclosed is a method of repairing a defective portion of a subsea pipeline, the method comprising: installing the pipeline clamp or modular pipeline clamp as set out above around the defective portion. Optionally, the method may further comprise introducing filler into the inlet. Also disclosed is a method of joining portions of a subsea pipeline together, the method comprising: installing the pipeline clamp or modular pipeline clamp as set out above around a joint between adjacent subsea pipeline portions. Optionally, the method may further comprise introducing filler into the inlet. Each feature disclosed in this specification (which term includes the claims) and / or shown in the drawings may be incorporated in the invention independently or in combination with any other disclosed and / or illustrated features. In particular but without limitation the features of any of the claims dependent from a particular independent claim may be introduced into that independent claim in any combination or individually. Brief Description of the Drawings The invention will now be described by way of example only with reference to the attached figures in which: Figure 1a is a perspective schematic illustration of a clamp for a pipeline; Figure 1b is a schematic cutaway view along the axis A-A of the clamp shown in Figure la; Figure 1c is a plan schematic illustration of the clamp shown in Figure 1a; Figure 1d is a side-on schematic illustration of the clamp shown in Figure 1a; Figure 2a is an alternative side-on illustration of the clamp shown in Figure 1a Figure 2b is a schematic illustration of the clamp shown in Figure 1d from the opposite side; Figure 2c is a schematic perspective illustration of the clamp shown in Figure 1a in use; Figure 3a is a schematic cutaway view along the axis B-B of the clamp shown in Figure 1a in use; Figure 3b is a schematic perspective view of one hemicylinder of a coupling means for coupling a modular clamp to another modular clamp; Figure 3c is a schematic cutaway view along the axis C-C of the coupling means shown in Figure 3b; Figure 4a is a perspective schematic illustration of a modular clamp installed on a pipeline, the modular clamp comprising a plurality of the clamps shown in Figure 1a; Figure 4b is a perspective schematic cutaway illustration of the modular clamp installed on a pipeline as shown in Figure 4a; Figure 5a is a perspective schematic illustration of an alternative clamp for a pipeline; Figure 5b is a schematic cutaway view along the axis D-D of the clamp shown in Figure 5a; Figure 6a is a plan schematic illustration of the clamp shown in Figure 5a; Figure 6b is a side-on schematic illustration of the clamp shown in Figure 5a; Figure 7a is a perspective schematic illustration of a modular clamp for a pipeline having two clamps of the type illustrated in Figure 5a; Figure 7b is a schematic cutaway view of the clamp shown in Figure 7a; Figure 8a is a schematic cutaway view of the clamp shown in Figure 7a installed onto a defective section of pipeline; Figure 8b is a schematic view of the clamp shown in Figure 8a installed onto a defective section of pipeline; Figure 9a is a schematic perspective view of two of the clamps illustrated in Figure 7a being used to replace a portion of defective pipeline; Figure 9b is a schematic perspective cutaway view of the clamps and replacement pipeline portion illustrated in Figure 9a; Figure 10a is a schematic perspective view of a modular repair clamp comprising a plurality ofclamps as shown in Figure 1a and Figure 5a; Figure 10b is a schematic perspective cutaway view of the modular repair clamp shown in Figure 10a in use; Figure 11 a is an exploded view of the modular repair clamp shown in Figure 10a; and Figure 11b is a side-on schematic illustration of the clamp shown in Figure 10a. In the figures, like elements are indicated by like reference numerals throughout. Detailed Description of Preferred Embodiments The present embodiments represent the best ways known to the Applicant of putting the invention into practice. However, they are not the only ways in which this can be achieved. Pipeline Clamp To overcome disadvantages with pipeline connectors, the present work discloses the use of a pipeline clamp for repairing / replacing sections of subsea pipelines. Reference will now be made to Figure 1a, which is a perspective schematic illustration of a clamp 1 for a pipeline according to a first example, Figure 1 b which is a schematic cutaway view along the axis A-A of the clamp 1 shown in Figure 1a, Figure 1c, which is a plan schematic illustration of the clamp shown in Figure 1a, and Figure 1 d, which is a side-on schematic illustration of the clamp shown in Figure 1a. As illustrated, the clamp 1 is formed of a first hemicylindrical portion comprising first and second clamping means 3-1,3-2, and a second hemicylindrical portion comprising third and fourth clamping means 3-3, 3-4, each of the first and second hemicylindrical portions having first and second ends. The first clamping means 3-1 and the third clamping means 3-3 are configured for mutual alignment, and the second clamping means 3-2 and the fourth clamping means 3-4 are also configured for mutual alignment, along an axis which is generally perpendicular to the longitudinal axis of the clamp 1. The clamp 1 also comprises an external coupling portion 5-1, 5-2 for receiving a coupling member (not illustrated) for coupling the pipeline clamp 1 to another pipeline clamp, and / or the clamp 1 may comprise one or more one or more locating means 2, disposed about a respective external perimeter of each of the first and second hemicylindrical portions, for mutually aligning the pipeline clamp with another pipeline clamp, as will be discussed in greater detail below. However, it will be appreciated that the external coupling portions 5-1, 5-2 for receiving a coupling member are optional. During installation (e.g. by divers, by remotely operated vehicles (ROVs), or the like), each of the first and second hemicylindrical portions will be offered up about the defective, e.g. leaking, pipe (as described in more detail below). Once the clamping means 3-1, 3-2, 3-3, 3-4 have been mutually aligned, the clamping means 3 are clamped together thereby clamping the first and second hemicylindrical portions together and forming the clamp 1 over the defective portion of pipeline. To assist the offering up of the first and second hemicylindrical portions to the defective pipe, a clamping means 3-2 of the first hemicylindrical portion may be hingedly connected by a hinge 6 to a clamping means 3-4 of the second hemicylindrical portion as shown in Figures 1 c, 1 d and 2a (although it will be appreciated that the hinged connection may instead be made between clamping means 3-1 of the first hemicylindrical portion and clamping means 3-3 of the second hemicylindrical portion). Whilst in the illustrated example the clamping means 3 takes the form of a pair of lugs projecting from each of the first and second hemicylindrical portions, through which three bolts may be secured to bring the first and second hemicylindrical portions into contact when tightened during installation, other means for clamping the hemicylindrical portions together may be used instead (such as lugs comprising receiving portions for fewer than three or more than four bolts). Each of the first and second hemicylindrical portions comprises first and second ends, with each of the first and second ends having a sealing region R for sealing against the pipeline in use (this is illustrated in Figure 1b, which shows regions R when taken along cross-section A-A shown in Figure 1a). Each of the sealing regions R may comprise an internal plurality of grooves for sealing against the subsea pipeline in use. For instance, the plurality of grooves may be formed from a rubberised sealing material, or the like, wherein the sealing material is suitable for subsea use. As shown in Figures 1a, 1b, 1c and 1 d, each of the first and second hemicylindrical portions respectively comprise an inlet 4-1, 4-2 (however, it will be appreciated that only one of the hemicylindrical portions may comprise such an inlet 4). Each inlet is configured to receive a filler for sealing / repairing the defective portion of pipeline over which the clamp 1 has been installed, as shown in Figure 2c (as described in more detail below), and hence clamp 1 can be considered as a leak-repair / leak prevention clamp. The filler may be an (injectable) polymer, or the like (e.g., an injectable elastomeric material). Specifically, once installed on a defective portion of a pipeline in the manner illustrated in Figure 2c, the first and second ends define a void between the sealing region R of the first end and the sealing region R of the second end. The void V is shown in Figure 3a (Figure 3a being a cross-section taken along the axis B-B illustrated in Figure 2c) and is formed circumferentially between the portion of defective pipeline P and the internal surface of the first and second hemicylinders of the clamp 1. As illustrated, void V is in fluidic communication with inlets 4-1, 4-2 and may therefore receive filler as needed during the repair operation to seal a leak which has formed in a defective portion of pipeline P. In one implementation, a pressure sensor may be provided at an inlet 4-1 (not illustrated), with a filling hose being provided at the other inlet 4-2 (not illustrated). An installer may determine that the filling of the void V has been achieved when the pressure sensor reaches a predetermined value. Providing two (or more) inlets may also facilitate the filling process by enabling displaced fluid (e.g. seawater) to exit the void V via one inlet as the void V is filled via another inlet. In addition to each of the first and second ends of the first and second hemicylindrical portions comprising the sealing region R, the first and second ends may additionally (or instead) comprise an external coupling portion 5-1, 5-2 for receiving an external coupling member / portion for coupling the pipeline clamp 1 to another pipeline clamp 1. In this way, a plurality of clamps 1 may be interconnected, in a modular fashion, to form a larger clamp as may be needed depending on the size of the defect in the defective pipeline (as discussed in more detail below). Specifically, a first part of an external coupling member 7 is shown in Figure 3b, whereby the first part of an external coupling member 7 is substantially hemicylindrical to facilitate mating with its corresponding coupling portion 5-1, 5-2 of the first / second hemicylindrical portion of the clamp 1 in use. The first part of the external coupling member 7 comprises clamping means 8-1, 8-2 for securing to corresponding clamping means of a second part of the external coupling member 7 in use. The clamping means 8-1, 8-2 are formed in a similar manner to the clamping means 3 used to clamp the first and second hemicylindrical portions of the clamp 1 together. Whilst in the illustrated example the clamping means 8-1, 8-2 takes the form of a pair of lugs projecting from each end of the first part of the external coupling member 7, through which two bolts may be secured to bring the first part of the external coupling member 7 into contact with the second part of the external coupling portion when tightened during installation, other means for clamping the external coupling portion together may be used instead (such as lugs comprising receiving portions for one or more bolts). As shown in more detail in Figure 3c (Figure 3c being a cross-section taken along the axis C-C illustrated in Figure 3b), the external coupling member 7 comprises a groove 9 which is configured to mate with a corresponding groove present on the external coupling portion 5-1, 5-2. Accordingly, and as shown in Figures 4a and 4b (Figure 4b being a cross-section taken along the axis D-D illustrated in Figure 4a), a tightly sealed interconnection is formed between adjacent clamps 1-1, 1-2, 1-3 by interposed external coupling members 7-1, 7-2 to form a modular clamp. Of course, whilst the modular clamp illustrated in Figures 4a and 4b comprises three of the above-described clamps 1 and two of the above-described external coupling members 7, it will be appreciated that a modular clamp may generally comprise n clamps 1 and n-1 external coupling members 7, as needed to fix the defective pipeline P. As noted above (and as illustrated e.g. in Figures 1a and 2a), each of the first and second hemicylindrical portions comprises one or more locating means 2, disposed about a respective external perimeter of each of the first and second hemicylindrical portions, for mutually aligning the pipeline clamp 1 with another pipeline clamp 1. Such an arrangement beneficially ensures, for example in the case of a modular clamp, the mutual alignment of components in use - such as inlets 4 being longitudinally aligned to assist the installer to rapidly introduce filler into the clamps 1. As illustrated, each of the locating means 2 comprises an eyelet protruding from each respective hemicylindrical portion, the eyelet being configured to receive a tie rod 10 in use. Whilst in the example illustrated with reference to Figures 1a and 1b, each of the locating means 2 comprises two eyelets mutually aligned along the clamp’s longitudinal axis for receiving the tie rod 10 in use, e.g. as shown in Figure 1a eyelets 2-1 and 2-7, 2-2 and 2-8, 2-3 and 2-9, 2-4 and 2-10, etc. are mutually aligned, each clamp 1 may comprise more than two longitudinally aligned eyelets. For instance, two longitudinally aligned eyelets may be used when the clamp 1 has a diameter of around 24 inches, whereas three or more eyelets may be used when the clamp 1 has a diameter of more than 24 inches. As illustrated in Figures 4a and 4b, a plurality of tie rods pass through mutually longitudinally aligned eyelets 2. At least one end of each tie rod 10 may comprise a thread for receiving a fastener, such as a bolt, to secure each tie rod 10 between the longitudinally aligned eyelets 2 of the connected pipeline clamps 1. The tie rods 10 may be installed once the first and second hemicylindrical portions of each clamp 1 have been fastened together with a respective interposing coupling member 7 being fastened between each clamp 1. By installing tie rods 10 in this way, the modular clamp may be aligned longitudinally and provided with greater structural integrity and robustness against longitudinal movement (thereby avoiding a recurrence of any leaks from the repaired pipeline). Longitudinal alignment of the inlets 4 may be particularly beneficial, e.g. when a diver wishes to fill each void of each clamp 1 simultaneously using a three-pronged filling manifold (or when using a multi-pronged filling manifold, depending on the number of inlets 4). Alternative Pipeline Clamp Reference will now be made to Figure 5a, which is a perspective schematic illustration of an alternative pipeline clamp 100 to another example, and to Figure 5b which is a schematic cutaway view along the axis D-D of the clamp 100 shown in Figure 5a. Clamp 100 is formed from a first hemicylindrical portion comprising first clamping means 30-1 and a second clamping means 30-2 (not illustrated), and a second hemicylindrical portion comprising a third clamping means 30-3 and a fourth clamping means 30-4 (not illustrated), each of the first and second hemicylindrical portions having first and second ends. The first clamping means 30-1 and the second clamping means 30-2 are configured for mutual alignment with the third clamping means 30-3 and the fourth clamping means 30-4 respectively, along an axis which is generally perpendicular to the longitudinal axis of the clamp 1. Each of the first ends of the first and second hemicylindrical portions have a sealing region R for sealing against the pipeline in use (which is analogous to the sealing region described above with respect to the clamp 1 according to the first example, the description of which will not be repeated here), and each of the second ends of the first and second hemicylindrical portions have an annular rim having an adjustable grip 40 configured for adjustment by one or more bolts 42. Accordingly, the clamp 100 is asymmetric along its length. The adjustable grip 40 may be a pipeline gripping system in which, upon the tightening / loosening of the one or more bolts 42, causes the adjustable grip to tighten against / loosen from the pipeline onto which the clamp 100 is installed, e.g. by the action of one or more rows of retractable gripping ball bearings / gripping wedges which grip against / loosen from the pipeline in response to the tightening / loosening of bolts 42. Given the presence of adjustable grip 40, clamp 100 may sometimes be referred to as a gripper clamp. In addition to each of the first ends of the first and second hemicylindrical portions comprising the sealing region R, the first ends of the first and second hemicylindrical portions may additionally (or instead) comprise an external coupling portion 50-1, 50-2 for receiving an external coupling member / portion for coupling the pipeline clamp 100 to another pipeline clamp. In this way, a plurality of clamps 100 may be interconnected, in a modular fashion, to form a larger clamp as may be needed depending on the size of the defect in the defective pipeline (as discussed in more detail below). The clamp 100 may also comprise one or more one or more locating means 20, disposed about a respective external perimeter of each of the first and second hemicylindrical portions, for mutually aligning the pipeline clamp 100 with another pipeline clamp (which will also be discussed in greater detail below). During installation, each of the first and second hemicylindrical portions will be offered up about the defective, e.g. cracked, pipe (as described in more detail below). Once the clamping means 30-1, 30-2, 30-3, 30-4 have been mutually aligned, the clamping means 30 are clamped together thereby clamping the first and second hemicylindrical portions together and forming the clamp 100 over the defective portion of pipeline. To assist the offering up of the first and second hemicylindrical portions to the defective pipe, a clamping means 30-1 of the first hemicylindrical portion may be hingedly connected by a pair of hinges 6-1, 6-2 (although one or more hinges may be used instead) to a clamping means 30-3 of the second hemicylindrical portion as shown in Figures 6a and 6b (Figures 6a and 6b show two clamps 100 connected by a coupling member 70, as will be described in more detail below). Whilst in the illustrated example the clamping means 3 takes the form of a pair of lugs projecting from each of the first and second hemicylindrical portions, through which four bolts may be secured to bring the first and second hemicylindrical portions into contact when tightened during installation, other means for clamping the hemicylindrical portions together may be used instead (such as lugs comprising receiving portions for fewer than four or more than five bolts). Optionally, the first and second hemicylinders of the clamp 100 may be connected by an actuatable piston 45 (e.g. a gas strut) for controlling the rate at which the first and second portions are brought together in use. In other words, the actuatable piston 45 effectively controls the rate at which the “clamshell” formed by the first and second hemicylinders of the clamp 100 are brought together once the clamp 100 has been offered up to the defective pipe - beneficially this avoids an otherwise potentially rapid closure of the components of the clamp 100 around the defective pipeline, which may otherwise cause further undesirable cracks / dents in the defective portion of pipeline. Figure 6b illustrates each of clamp 100-1 having an actuatable piston 45-1 and clamp 100-2 having an actuatable piston 45-2, thereby the rate at which the hemicylindrical portions of each clamp 100-1, 100-2 may be closed can be controlled simultaneously as needed. To repair a cracked portion of pipeline, two clamps 100-1, 100-2 may be coupled together, in a modular fashion, by using one of the coupling members 7 described in detail above (and hence the description of which will not be repeated again here) interposed between the two clamps 100-1, 100-2 as shown in Figures 6a, 6b and 7a to form what may be termed a structural clamp 1000. The structural clamp 1000 is shown in a cutaway perspective view in Figure 8a having been installed over a defective section DS of cracked pipe P, and shown in perspective view in Figure 8b having been installed over the defective section DS of cracked pipe P. As noted above (and as illustrated in Figures 7a to 8b), each of the first and second hemicylindrical portions comprises one or more locating means 20, disposed about a respective external perimeter of each of the first and second hemicylindrical portions, for mutually aligning the pipeline clamp 100 with another pipeline clamp 100. Such an arrangement beneficially ensures, for example in the case of the structural clamp 1000, the mutual alignment of components in use - such as the actuatable pistons 45 being longitudinally aligned to assist the installer to carefully install the structural clamp. As illustrated, each of the locating means 20 comprises an eyelet protruding from each respective hemicylindrical portion, the eyelet being configured to receive a tie rod 10 in use as described in detail below. Whilst in the example illustrated with reference to Figures 5a to 8b, each of the locating means 20 comprises two eyelets mutually aligned along the clamp’s longitudinal axis for receiving the tie rod 10 in use, e.g. as shown in Figure 5a eyelets 20-1 and 20-7, 20-2 and 20-8, 20-3 and 20-9, 20-4 and 20-10, etc. are mutually aligned, each clamp 100 may comprise more than two longitudinally aligned eyelets. For instance, two longitudinally aligned eyelets may be used when the clamp 100 has a diameter of around 24 inches, three or more eyelets may be used when the clamp 100 has a diameter of more than 24 inches. As illustrated in Figures 6a to 8b, a plurality of tie rods 10 pass through mutually longitudinally aligned eyelets 20. At least one end of each tie rod 10 may comprise a thread for receiving a fastener, such as a bolt, to secure each tie rod 10 between the longitudinally aligned eyelets 20 of the connected pipeline clamps 100. The tie rods 60 may be installed once the first and second hemicylindrical portions of each clamp 100 have been fastened together with a respective interposing coupling member 7 being fastened between each clamp 100. By installing tie rods 60 in this way, the modular structural clamp may be aligned longitudinally and provided with greater structural integrity and robustness against longitudinal movement (thereby avoiding a recurrence of any further cracks along the repaired pipeline). In some circumstances, a portion of subsea pipeline may be too defective to warrant repair and instead complete replacement of that portion of pipeline may be necessary (e.g. in the case where an anchor is dragged over a portion of pipeline, thereby severely rupturing the pipeline). In this regard, reference is now made to Figures 9a and 9b which show the use of a first 1000-1 and a second 1000-2 of the abovedescribed structural clamps 1000 in replacing a damaged section of pipeline P. Specifically, a defective portion of pipeline is first cut away from the remainder of the pipeline P. Then, a replacement section of pipeline RP is offered up to the remainder of the pipeline P, at each end of which a structural clamp 1000-1, 1000-2 is provided and enclosed around the joint between the replacement section of pipeline and the remaining pipeline P, thereby securing the replacement portion of pipeline RP to the remainder of the pipeline P. Modular Repair Clamp A first clamp 1 and a modular clamp comprising a plurality of clamps 1 has been described above. Also, an alternative clamp 100 and a modular clamp 1000 comprising a two of clamps 100 has been described above. Now, with reference to Figures 10a to 13b, a modular repair clamp comprising clamps 1, coupling members 7, and clamps 100 will now be described. Specifically, as shown in Figure 10a, a modular repair clamp may be formed from a clamp 100-1 at a first end of the modular repair clamp and a clamp 100-2 at a second end of the modular repair clamp. In between the terminating clamps 100-1, 100-2, three leak repair clamps 1-1, 1-2, 1-3 are provided, with coupling member 7-1 coupling clamp 100-1 and clamp 1-1 together, coupling member 7-2 coupling clamp 1-1 and clamp 1-2 together, coupling member 7-3 coupling clamp 1-2 and clamp 1-3 together, and coupling member 7-4 coupling clamp 1-3 and clamp 100-2 together. Hence, the coupling members 7 are interposed between clamps 1, 100 to couple the entirety of the modular repair clamp together. Beneficially, pipeline operators may keep a stock of the above-described components and deploy as many components as may be needed to effect repair of a defective portion of subsea pipeline. For instance, whilst the modular repair clamp shown in Figures 10 to 13b comprises three leak repair clamps 1 -1, 1-2, 1 -3, more than three or fewer than three (e.g. one or two) leak repair clamps 1 may be used as needed. The modular repair clamp shown in Figure 10a is shown, installed onto a pipeline P, in cutaway view in Figure 10b. Beneficially, the modular repair clamp combines the benefits of the leak repair clamp 1 and the gripping clamp 100 into a single modular unit, i.e. an elongate sealing zone can be provided in the area enclosed by sealing clamps 1-1,1 -2, 1-3 by filling of the void V1, V2, V3 respectively associated with each sealing clamp 1-1, 1-2, 1-3 with filler, whilst the structural rigidity and speed of assembly of the modular repair clamp can be controlled by using gripping claims 100-1, 100-2. Figure 11a shows an exploded view of the components forming the modular repair clamp illustrated in Figures 10a and 10b. Whilst in Figures 10a to 11b the modular repair clamp is illustrated having a plurality of locating means 2, 20, disposed about a respective external perimeter of each of the first and second hemicylindrical portions of each clamp 1, 100, with each of the locating means comprising an eyelet protruding from the respective hemicylindrical portion for receiving a tie rod 10 in use, it will be appreciated that these features are optional and that the modular repair clamp need not incorporate these optional features. Figure 11b shows a side view of the modular repair clamp illustrated in Figure 10a. From the perspective shown in Figure 11b, it can clearly be seen that the hemicylinders of the respective clamps are hingedly connected, and that the hemicylinders of the clamps 100-1, 100-2 each comprise an actuatable piston 45-1, 45-2 for controlling the rate at which the first and second portions of the first and second hemicylinders of each clamp 100-1, 100-2 are brought together in use. However, it will be appreciated that a hinged connection and / or the use of actuatable pistons are entirely optional in the context of the modular repair clamp, and that these features need to be necessary for the modular repair clamp to perform its function. Modifications and Alternatives Detailed examples have been described above. As those skilled in the art will appreciate, a number of modifications and alternatives can be made to the above examples whilst still benefiting from the inventions embodied therein. Whilst the pipeline clamps / connectors, modular clamps, and modular repair clamps have been described above in the context of subsea applications, it will be appreciated that these pipeline clamps / connectors, modular clamps, and modular repair clamps may also be used on land (e.g., to repair defective pipelines in refining facilities, factories, or the like). In the examples described above, the coupling member 7 comprised a “female” portion into which the “male” external coupling portions 5-1,5-2. 50-1, 50-2 of the clamps 1, 100 are received. Alternatively, the external coupling portions 5-1, 5-2. 50-1, 50-2 of the clamps 1, 100 may comprise a “female” portion into which a “male” portion of the coupling member 7 is received. In the examples described above, an actuatable piston 45 may be used to regulate when and the speed at which the two hemicylindrical portions of clamp 100 are brought together. Instead of an actuatable piston 45, a “passive” piston may be used, whereby the “passive” piston simply acts to regulate the closing speed when the two hemicylindrical portions of clamp 100 are being brought together. 5 Various other modifications will be apparent to those skilled in the art and will not be described in further detail here.

Claims

1. A pipeline clamp for connecting to a subsea pipeline, the pipeline connector comprising:a first hemicylindrical portion comprising first and second clamping means,a second hemicylindrical portion comprising third and fourth clamping means, wherein the first and third clamping means and the second and fourth clamping means are configured for mutual alignment;wherein each of the first and second hemicylindrical portions comprises first and second ends, each of the first and second ends having a sealing region for sealing the pipeline in use, and defining a void between the sealing region of the first end and the sealing region of the second end; andwherein at least one of the first and second hemicylindrical portions further comprises an inlet, in communication with the void, for receiving a filler.

2. The pipeline clamp according to claim 1, wherein each sealing region comprises an internal plurality of grooves for sealing the subsea pipeline in use.

3. The pipeline clamp according to claim 1 or claim 2, wherein the first and third clamping means are hingedly connected.

4. The pipeline clamp according to any preceding claim, wherein at least one of the first and second ends of the first and second hemicylindrical portions comprises an external coupling portion for receiving a coupling member for coupling the pipeline clamp to another pipeline clamp.

5. The pipeline clamp according to claim 4, wherein each of the first and second hemicylindrical portions comprises one or more locating means, disposed about a respective external perimeter of each of the first and second hemicylindrical portions, for mutually aligning the pipeline clamp with another pipeline clamp.

6. The pipeline clamp according to claim 5, wherein each of the locating means comprises an eyelet protruding from the respective hemicylindrical portion for receiving a tie rod in use.

7. The pipeline clamp according to claim 6, wherein each of the locating means comprises two or more eyelets mutually aligned along a longitudinal axis for receiving the tie rod in use.

8. A modular pipeline clamp comprising a plurality of pipeline clamps according to any of claims 4 to 7, andone or more coupling members for coupling the pipeline clamps, wherein each coupling member is configured to interpose between adjacent pipeline clamps and to engage with the external coupling portion of each of the adjacent pipeline clamps.

9. The modular pipeline clamp of claim 8 when dependent on claim 6 or claim 7, further comprising a plurality of tie rods configured to pass through mutually longitudinally aligned eyelets, wherein at least one end of each tie rod comprises a thread for receiving a fastener to secure each tie rod between the longitudinally aligned eyelets of the connected pipeline clamps.

10. A pipeline clamp for connecting to a subsea pipeline, the pipeline clamp comprising:a first hemicylindrical portion comprising first and second clamping means;a second hemicylindrical portion comprising third and fourth clamping means, wherein the first and third clamping means and the second and fourth clamping means are configured for mutual alignment;wherein each of the first and second hemicylindrical portions comprises first and second ends, each of the first ends having a sealing region for sealing the pipeline in use; andwherein each of the second ends comprises an annular rim having an adjustable grip configured for adjustment by one or more bolts.

11. The pipeline clamp according to claim 10, wherein the sealing region comprises an internal plurality of grooves for sealing the subsea pipeline in use and the adjustable grip is a pipeline gripping system comprising rows of gripping balls and / or gripping wedges which are adjustable by the one or more bolts for gripping the pipeline in use.

12. The pipeline clamp according to claim 10 or claim 11, wherein the first and third clamping means are hingedly connected.

13. The pipeline clamp according to any of claims 10 to 12, wherein each of the first ends of the first and second hemicylindrical portions comprises an external coupling portion for receiving a coupling member for coupling the pipeline clamp to another pipeline clamp.

14. The pipeline clamp according to claim 13, wherein each of the first and second hemicylindrical portions comprises one or more locating means, disposed about a respective external perimeter of each of the first and second hemicylindrical portions, for mutually aligning the pipeline clamp with another pipeline clamp.

15. The pipeline clamp according to claim 14, wherein each of the locating means comprises an eyelet protruding from the respective hemicylindrical portion for receiving a tie rod in use.

16. The pipeline clamp according to claim 15, wherein each of the locating means comprises two or more eyelets mutually aligned along a longitudinal axis for receiving the tie rod in use.

17. The pipeline clamp according to any of claims 10 to 16, wherein the first and second hemicylindrical portions are connected by an actuatable piston for controlling the rate at which the first and second portions are brought together in use.

18. A modular pipeline clamp comprising two pipeline clamps according to any of claims 13 to 17; anda coupling member for coupling the pipeline clamps, wherein the coupling member is configured to interpose between each pipeline clamp and to engage with the external coupling portion of each pipeline clamp.

19. The modular pipeline clamp of claim 18 when dependent on claim 15 or claim 16, further comprising a plurality of tie rods configured to pass through mutuallylongitudinally aligned eyelets, wherein at least one end of each tie rod comprises a thread for receiving a fastener to secure each tie rod between the longitudinally aligned eyelets of the connected pipeline clamps.

20. A modular pipeline clamp, comprising:at least one of the pipeline clamps according to any of claims 4 to 7; two of the pipeline clamps according to any of claims 13 to 17; and a plurality of coupling members for coupling the pipeline clamps, wherein each coupling member is configured to interpose between adjacent pipeline clamps and to engage with the external coupling portion of each of the adjacent pipeline clamps.

21. The modular pipeline clamp of claim 20 when dependent on claim 6 or claim 7 and on claim 15 or claim 16, further comprising a plurality of tie rods configured to pass through mutually longitudinally aligned eyelets, wherein at least one end of each tie rod comprises a thread for receiving a fastener to secure each tie rod between the longitudinally aligned eyelets of the connected pipeline clamps.

22. A method of repairing a defective portion of a subsea pipeline, the method comprising:installing the pipeline clamp or modular pipeline clamp of any preceding claim around the defective portion.

23. The method according to claim 22 when dependent on any of claims 1 to 9, further comprising introducing filler into the inlet.

24. A method of joining portions of a subsea pipeline together, the method comprising: installing the pipeline clamp or modular pipeline clamp of any preceding claim around a joint between adjacent subsea pipeline portions.

25. The method according to claim 24 when dependent on any of claims 1 to 9, further comprising introducing filler into the inlet.

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