WO2012076894A1

WO2012076894A1 - Clamp

Info

Publication number: WO2012076894A1
Application number: PCT/GB2011/052435
Authority: WO
Inventors: Austin Harbison; Geoffrey Wild
Original assignee: Trelleborg Offshore U.K. Ltd
Priority date: 2010-12-10
Filing date: 2011-12-08
Publication date: 2012-06-14
Also published as: GB201112116D0; GB201020984D0

Abstract

A clamp is disclosed for mounting a secondary elongate member (36, 38) (which may for example be an umbilical or relatively small pips) upon, and in parallel relationship with, a primary elongate member ( 16) (which may for example be a riser of the type used in hydrocarbon extraction). The clamp comprises a clamp body (12,1 12) having a saddle (18, 118) for seating upon the primary elongate member and a channel-forming structure (26, 182) upstanding from the saddle and defining a channel for receiving and mounting the secondary elongate member. The saddle is adapted to bend to enable it to seat upon primary elongate members having a range of lateral dimensions.

Description

CLAMP

The present invention relates to a clamp for use in mounting one or more secondary elongate members, such as pipelines or cables, on a primary elongate member such as a larger pipeline or riser. Such devices are often referred to as "piggyback clamps" since the secondary member is piggybacked on the primary member.

Piggyback clamps are often (but not necessarily exclusively) used in underwater applications. In a typical situation, one or more smaller diameter members such as pipes are to be mounted in close parallel relationship with another pipeline of larger diameter. For example an oil or gas pipeline laying operation may have a requirement to simultaneously lay a small diameter service line. Piggybacking the service line on the primary pipeline ensures that it is adequately supported, both during laying, between the surface and the sea bed, and subsequently.

A clamping assembly for piggyback mounting a secondary elongate member on a primary elongate member is disclosed in GB 2267137 and has a saddle shaped to seat upon the primary elongate member and to receive a strap placed around both the saddle and the primary elongate member to mount the saddle thereupon. The saddle also defines a channel of semi-circular section to receive the secondary elongate member. A saddle cover has a complementary semi-circular channel and is bolted in place to retain the secondary elongate member. While such clamps have been successful, it would for certain applications be desirable to improve upon them in one or more of the following respects:

1. It would be advantageous to be able to manufacture a single clamp mountable upon primary elongate members having a range of diameters;

2. In some cases the secondary elongate member may not be mounted upon the primary elongate member prior to laying. Instead the clamps would be secured to the primary elongate member and the secondary elongate member would be secured to the clamps whilst on the sea bed, e.g. by divers. In this context it is important that the process of mounting and securing the secondary elongate member to the clamp should be as straightforward as possible, and in particular that it should not involve placing a strap around the primary elongate member.

3. The cost of the clamps should be minimised.

According to a first aspect of the present invention, there is clamp for mounting a secondary elongate member upon, and in parallel relationship with, a primary elongate member, the clamp comprising a clamp body having a saddle for seating upon the primary elongate member and a channel-forming structure upstanding from the saddle and defining a channel for receiving and mounting the secondary elongate member, the saddle portion being adapted to bend to enable it to seat upon primary elongate members having a range of lateral dimensions.

The combination of a bendable saddle portion and a channel-forming structure upstanding from it provides a clamp which is able to accommodate and seat securely upon primary elongate members having a range of different lateral dimensions (typically the lateral dimension is a diameter, although there is no requirement that the primary elongate member should be precisely round in section).

The channel serves to receive and/or support the secondary elongate member and to allow that member to be secured in position. It may take the form of a trough or semi-cylinder, but can take any number of different shapes commensurate with its function.

The saddle preferably comprises a flexible plate, although the plate may be shaped to define e.g. troughs for receiving and locating securing straps.

Preferably the plate has a part-circular curve. In this way it is pre-formed to be able to seat upon the primary elongate member. Preferably the saddle has peripheral portions on either side of the channel-forming structure around which straps are able to be passed to secure the clamp body to the primary elongate member. This provides a constructionally convenient way to secure the clamp in place.

Preferably the clamp body is shaped to enable a retaining strap to be passed around a secondary elongate member mounted in the channel to retain the secondary elongate member in place. In a preferred embodiment the channel has an open mouth for receiving the secondary elongate member and at least one hinged flap is provided for closing the mouth. The hinged flap(s) can serve to prevent the means used to retain the secondary elongate member (such as a strap) from contacting and potentially damaging the secondary elongate member. The flap may be integrally formed with the clamp body and coupled to it through a living hinge.

Preferably the channel has a base portion which is part-circular or part-oval in shape. The secondary elongate member may be received directly in the channel, or alternatively, and according to a particularly preferred embodiment of the invention, the clamp may further comprise an insert removably mountable in the channel, the insert being shaped to receive and mount at least one secondary elongate member. Multiple inserts may be manufactured/supplied to allow a single clamp body to be used to mount a range of different sizes and/or combinations of secondary elongate members. Preferably the channel and the insert are provided with complementary locating features to positively locate the insert when it is mounted in the channel. It is preferred that the insert is a snap fit in the channel. The insert may be generally circular or oval in shape.

Preferably the clamp body further comprises a set of features upstanding from the saddle on two sides of the channel-forming structure. The upstanding features are separated from one another thereby permitting the saddle to bend to conform to the primary elongate member. It is particularly preferred that the upstanding features together define ramp surfaces on the two sides of the channel-forming structure around which a strap is able to be passed to secure the clamp body in place on the primary elongate member.

The clamp body is preferably a unitary plastics moulding. It may in particular be injection moulded.

According to a second aspect of the present invention, there is a clamp for mounting a secondary elongate member upon, and in parallel relationship with, a primary elongate member, the clamp comprising a clamp body which is shaped to provide an inwardly concave saddle surface for seating upon a primary elongate member and a channel having an outwardly open mouth, the clamp further comprising a securing device for securing the clamp body to the primary elongate member and an insert formed separately from the clamp body and shaped to be received and mounted in the channel, the insert having at least one insert-channel for receiving and mounting the secondary elongate member.

Specific embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which :-

Figure 1 is a perspective representation of a first clamp embodying the present invention;

Figure 2 shows the first clamp mounted upon a primary pipeline and carrying a small diameter secondary pipeline; and

Figure 3 is similar to Figure 2 but shows the first clamp mounting a larger diameter secondary pipeline; and Figure 4 is a detail view of part of a clamp body of the first clamp;

Figure 5 is a perspective representation of a second clamp embodying the present invention having a hinged retainer for retaining the secondary elongate member, the retainer being shown in an open position in this drawing;

Figure 6 is similar to Figure 5 but shows the retainer in a first closed position; and

Figure 7 is similar to Figure 5 but shows the retainer in a second closed position.

The first clamp 10 seen in Figures 1 to 4 comprises a clamp body 12 and an insert 14 which is removably mountable on the clamp body 12. In the illustrated example the clamp body 12 is a unitary plastics moulding, most preferably an injection moulding. It has a saddle portion, for seating upon the primary pipeline 16, formed as a flexible curved plate 18. Viewed along the axis of a pipeline on which it seats, the saddle is generally part-circular. Due to its flexibility, the clamp body can be mounted upon, and conform to, a range of different primary pipeline diameters. This can for example improve the attractiveness of the product to customers, reduce the need for clamps to be tailor made for given applications and alleviate requirements to manufacture/hold a range of different clamps.

The clamp body 12 is to be secured to the primary pipeline 16 by means of two straps 20, 22 which seat in shallow troughs formed in exposed peripheral portions of the saddle 18 and extend circumferentially with respect to the primary pipeline 16 on which the clamp body sits. Between the troughs, integrally formed with the saddle 18 and upstanding from it, is a channel-forming structure 26. In the present embodiment this comprises an upstanding pair of side walls 28, 30 which are generally planar. Between them is formed a pair of channel-defining walls 32, 34 which are curved to form an outwardly concave and outwardly open channel 40 for receiving the secondary elongate member. In Figure 1 it can be seen that the removable insert 14 is mounted in the channel 40. The insert might appear circular in the drawings but in the present embodiment it is actually oval so that it is not able to rotate relative to the clamp body, the channel 40 itself being a matching oval shape at its base. Also the channel 40 and insert have complementary locating features to positively locate the insert 14 once mounted. In Figure 4 axial-locating ridge 42 can be seen. This is one of a set of such ridges and the insert 14 has matching troughs (not seen) in its outer surface to receive the ridges 42 and so prevent the insert 14 from moving axially.

The insert 14 is shaped to receive and mount one or more secondary pipelines (or secondary elongate members of other types). The provision of an insert means that a single clamp body 12 can be used to mount a range of different sizes and/or combinations of secondary pipelines, by use of different inserts. The example seen in Figure 1 has a pair of part-circular, outwardly open insert-channels 44, 46 of different sizes to receive respective secondary pipelines of different diameters. Other inserts could be adapted to mount more secondary pipelines. Figure 2 shows a single secondary pipeline 36 mounted in the insert 14. Figure 3 shows an alternative configuration in which the insert 14 is dispensed with and a secondary pipeline 38 of larger diameter is received directly in the channel 40 of the clamp body 12.

It is necessary to secure the secondary pipeline 36, 38 in place on the clamp body 12 and to this end the channel-forming structure 26 has a pair of flaps 50, 52 coupled to outer edges of the channel 40's upstanding side walls 28, 30 through integral hinges, sometimes referred to as "living hinges". After the insert 14 and the pipeline 36, or the pipeline 38 alone, has been positioned in the channel 40 of the clamp body 12, the flaps 50, 52 are folded down to retain it in position and are kept in this configuration by a retaining strap 54. The retaining strap 54 is preferably pre-installed, being passed through slots (not seen) in the clamp body 12 to enable it to pass beneath the secondary pipeline and to retain it in position.

On either side of the channel-forming structure 26 there is a set of features 60, 62 upstanding from the saddle 18. In the illustrated embodiment these are generally "n" shaped, having a pair of upstanding walls 64, 66 joined by a sloped roof or cross member 68. This configuration gives the clamp body 12 some rigidity in the axial direction (i.e. in the direction along the length of the elongate members 16, 36, 38) without preventing it from bending as necessary to seat upon the primary elongate member 16. Each upstanding feature 60, 62 is distinct from its neighbour and separated from it, which again assists in giving the clamp body 12 the required capacity to bend. The heights of the upstanding features 60, 62 diminish with distance from the channel-forming structure 26 and their inclined roofs 68 together form, on either side of the structure 26, a ramp upon which a strap (not shown) can be conveniently mounted, shallow troughs 70 being formed therein to locate that strap.

The clamp 10 can thus be used in two different ways.

In the first mode of use, the clamp bodies 12 are mounted on the primary pipeline 16 before it is laid (e.g. on the sea bed) by means of the straps 20, 22. After laying of the pipeline 16, the secondary pipeline 36, 38 is inserted into the clamp body 12 (with or without the insert 14, according to requirements) and the retaining strap 54 is used to secure it in place.

In the second mode of use the secondary pipeline 36, 38 is mounted prior to deployment of the primary pipeline 16. In this case the same straps 20, 22, 54 may be used, or, additionally or alternatively, a single strap (not shown) may be placed around the primary pipeline 16 and the clamp body 12, running around the upstanding features 60, 62 in their shallow channels 70, to keep the retaining flaps 50, 52 closed and to secure the clamp in place.

A reinforcing plate (not seen in the drawings) may be incorporated in the saddle plate 18 to transfer loading from the channel-forming structure 26 to the straps 20, 22. This may for example take the form of a metal plate beneath the structure 26 and extending beneath the straps 20, 22. This may be incorporated straightforwardly during the moulding process.

The second clamp 100, which is depicted in Figures 5 to 7, is in many respects similar to the first clamp 10, having a clamp body 112 with a saddle portion formed as a flexible curved plate 118, the saddle portion being adapted to be secured to a primary pipeline by means of straps which are omitted from Figures 5 to 7. The second clamp 100 has "n" shaped upstanding features 160, 162 similarly formed to those of the first clamp.

The distinctions between the first and second clamps 10, 100 relate to the arrangement used to mount and secure the secondary pipeline. Where the first clamp uses a retaining strap 54 for this purpose, the second clamp 100 has instead a hinged retainer 180 which can be secured in any of a plurality of different closed positions to accommodate a range of different pipeline diameters.

In the second clamp 100 outwardly open channel 140 is defined by a part- cylindrical channel member 182 supported on the curved plate 1 18 through short legs 184. The retainer 180 is coupled to one side of the channel member 182 through a hinge arrangement 183 enabling it to move between an open position (Figure 5) for insertion of the secondary pipeline (not shown) and any of a set of closed positions (Figures 5 and 6) in which the channel member 182 and the retainer 180 together encircle the secondary pipeline to maintain it in position. The retainer 180 is in the illustrated embodiment part-cylindrical in shape so that its inner surface 186 is suitably shaped to embrace a secondary pipeline of a circular cross section. It has a double-walled construction which allows it to be robust but also somewhat flexible. The retainer 180 is provided with a locking mechanism for retaining it in any of the closed positions. In the illustrated embodiment the locking mechanism comprises a sliding bolt 188. On the side of the channel member 182 opposite the hinge 183 are formed a set of tubular structures 190 providing through-going openings 192. In the illustrated embodiment there are three of these openings, one of which is largely concealed, but other embodiments may have a different number of openings 192. The retainer 180 is cut away as seen at 194 so that in its closed positions portions 196, 198 carrying openings 202 lie on opposite sides of the tubular structures 190. When the retainer is in one of the closed positions, sliding the bolt through aligned openings 192, 202 (as in Figure 6) retains it securely in position. Because the retainer 180 can be locked in any of a set of different closed positions (there are three of them in the present embodiment, although the number of positions may be different in other embodiments) the second clamp 100 can be used to mount secondary pipelines having a range of different diameters. This range can be expanded by providing inserts or bushings which receive the secondary pipeline and are secured by the retainer arrangement, and as in the first described embodiment such inserts can have multiple openings to mount multiple secondary pipelines.

Claims

1. A clamp for mounting a secondary elongate member upon, and in parallel relationship with, a primary elongate member, the clamp comprising a clamp body having a saddle for seating upon the primary elongate member and a channel -forming structure upstanding from the saddle and defining a channel for receiving and mounting the secondary elongate member, the saddle portion being adapted to bend to enable it to seat upon primary elongate members having a range of lateral dimensions.

2. A clamp as claimed in claim 1 in which the saddle comprises a flexible plate.

3. A clamp as claimed in claim 2 in which the said plate has a part-circular curve.

4. A clamp as claimed in any preceding claim in which the saddle has peripheral portions on either side of the channel- forming structure around which straps are able to be passed to secure the clamp body to the primary elongate member.

5. A clamp as claimed in any preceding claim further comprising a hinged retainer which is movable between an open position in which it allows the secondary elongate member to be received in the channel and a closed position in which it retains the secondary elongate member in the channel.

6. A clamp as claimed in claim 5 further comprising a locking mechanism for locking the retainer in any of a plurality of closed positions.

7. A clamp as claimed in claim 6 in which the locking mechanism comprises a sliding bolt.

8. A clamp as claimed in any of claims 1 to 4 in which the clamp body is shaped to enable a retaining strap to be passed around a secondary elongate member mounted in the channel to retain the secondary elongate member in place.

9. A clamp as claimed in any of claims 1 to 4 or 8 in which the channel has an open mouth for receiving the secondary elongate member and in which at least one hinged flap is provided for closing the mouth.

10. A clamp as claimed in claim 9 in which the flap is integrally formed with the clamp body and is coupled to it through a living hinge.

11. A clamp as claimed in any preceding claim in which the channel has a base portion which is part-circular or part-oval in shape.

12. A clamp as claimed in any preceding claim which further comprises an insert removably mountable in the channel, the insert being shaped to receive and mount at least one secondary elongate member.

13. A clamp as claimed in claim 12 in which the channel and the insert are provided with complementary locating features to positively locate the insert when it is mounted in the channel.

14. A clamp as claimed in claim 12 or claim 13 in which the insert is generally circular or oval in shape.

15. A clamp as claimed in any preceding claim in which the clamp body further comprises a set of features upstanding from the saddle on two sides of the channel -forming structure.

16. A clamp as claimed in claim 15 in which the upstanding features are separated from one another thereby permitting the saddle to bend.

17. A clamp as claimed in claim 15 or claim 16 in which the upstanding features together define ramp surfaces on the two sides of the channel-forming structure around which a strap is able to be passed to secure the clamp body in place on the primary elongate member.

18. A clamp as claimed in any preceding claim in which the clamp body is a unitary plastics moulding.

19. A clamp for mounting a secondary elongate member upon, and in parallel relationship with, a primary elongate member, the clamp comprising a clamp body which is shaped to provide an inwardly concave saddle surface for seating upon a primary elongate member and a channel having an outwardly open mouth, the clamp further comprising a securing device for securing the clamp body to the primary elongate member and an insert formed separately from the clamp body and shaped to be received and mounted in the channel, the insert having at least one insert-channel for receiving and mounting the secondary elongate member.

20. A clamp as claimed in claim 19 in which the securing device comprises at least one strap to be passed around the clamp body and the primary elongate member to secure the clamp body to the primary elongate member.

21. A clamp as claimed in claim 19 or claim 20 in which the saddle surface is formed by the inner face of a flexible saddle plate.

22. A clamp as claimed in claim 21 in which the saddle plate has a part-circular curve.

23. A clamp as claimed in any of claims 19 to 22 in which the saddle plate has peripheral portions on either side of the channel- forming structure around which straps are able to be passed to secure the clamp body to the primary elongate member.

24. A clamp as claimed in any of claims 19 to 23 in which the clamp body is shaped to enable a retaining strap to be passed around the insert when it is mounted in the channel to retain the insert in place.

25. A clamp as claimed in any of claims 19 to 24 in which the channel has an open mouth for receiving the insert and a secondary elongate member mounted in the insert, and in which at least one hinged flap is provided for closing the mouth.

26. A clamp as claimed in claim 25 in which the flap is integrally formed with the clamp body and is coupled to it through a living hinge.

27. A clamp as claimed in any of claims 19 to 26 in which the channel and the insert are provided with complementary locating features to positively locate the insert when it is mounted in the channel.

28. A clamp as claimed in any of claims 19 to 27 in which the insert is generally circular or oval in shape and the channel has a base portion which is complementarily shaped.

29. A clamp as claimed in claim 21 or in any subsequent claim when dependent on claim 21 in which the clamp body further comprises a set of features upstanding from the saddle plate on two sides of the channel.

30. A clamp as claimed in claim 29 in which the upstanding features are separated from one another thereby permitting the saddle plate to bend.

31. A clamp as claimed in claim 29 or claim 30 in which the upstanding features together define ramp surfaces on the two sides of the channel-forming structure around which a strap is able to be passed to secure the clamp body in place on the primary elongate member.

32. A clamp as claimed in any of claims 19 to 31 in which the clamp body is a unitary plastics moulding.

33. A clamp for mounting a secondary elongate member upon, and in parallel relationship with, a primary elongate member, the clamp comprising

a clamp body having a saddle for seating upon the primary elongate member and a channel-forming structure upstanding from the saddle and defining a channel for receiving and mounting the secondary elongate member, a retainer coupled to the clamp body through a hinge so that the retainer is movable between an open position which enables the secondary elongate member to be received by the channel, and a closed position in which it retains the secondary elongate member in the channel, and

a locking mechanism for locking the retainer in the closed position.

34. A clamp as claimed in claim 33 in which the locking mechanism comprises a sliding bolt.

35. A clamp as claimed in claim 33 or claim 34 in which the locking mechanism is adapted to lock the retainer in any of a plurality of closed positions to enable the clamp to accommodate secondary elongate members having a range of lateral dimensions.

36 A clamp substantially as herein described with reference to, and as illustrated in, (a) Figures 1 to 4 or (b) Figures 5 to 7.

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