NO337045B1

NO337045B1 - A support device

Info

Publication number: NO337045B1
Application number: NO20150110A
Authority: NO
Inventors: Sven Erik Helgesen
Original assignee: Eureka Pumps As
Priority date: 2015-01-23
Filing date: 2015-01-23
Publication date: 2016-01-11
Also published as: NO20150110A1

Description

A hang-off tool

Field of the invention

The invention concerns a hang-off tool for supporting an elongate object, as set out by the preamble of claim 1; the use of the hang-off tool as set out by claim 7; and method of installing a pipe in into a caission as set out by the preamble of claim 9.

Background of the invention

Referring to figure 1, firewater systems for floating vessels 1 (ships, platforms, etc.) normally comprise a power unit 2 (e.g. a diesel-driven power generator) that is connected (e.g. via electrical wires, not shown) to a submerged pump 3 (typically håving an electrical motor) arranged in an opening 23 in the vessel hull, below the water surface W. The submerged pump 3 is arranged at the end of a pipe 11 which extends in a caisson 5 from the vessel deck D. On the deck, the pipe 11 is connected to one or more pipes 4, and thus supplies water to firefighting equipment, sprinkler systems, etc. This configuration is well known in the art.

From time to time, the submerged pump must be retrieved to the deck for repair, refurbishment or replacement. This operation entails disconnecting the pipe 11 from the distribution pipes 4 (and ancillary support members; not shown) and temporarily suspending the pipe 11 (to which the submerged pump 3 is connected) by temporary support structures. One such known temporary support structure, which is shown in figure 2 and commonly referred to as a hang-off tool, comprises a frame structure håving four interconnected frame members 6a-d, configured for being placed on the deck D, and provided with lifting bars 8. The known hang-off tool comprises support tabs 7, on which the pipe is supported (e.g. via a pipe flange). In use, the frame members are disconnected and placed around the pipe 11, whereupon the pipe flange is lowered such that the pipe - and pump - are supported by the hang-off tool. The individual frame members are relatively heavy (e.g. 60 - 80 kg) and require multiple persons or a crane for lifting an handling. The process of assembling and disassembling the hang-off tool is therefore time-consuming and potentially hazardous.

WO 2013009847 A2 describes hang-off tool for supporting a tool inside a tubular member. The tool includes a logging string, a computing system coupled to the logging string, and a radially expandable member håving a retracted position and an expanded position. The radially expandable member is configured to engage a radially-increased profile of an inner surface of the tubular member in the expanded position to support the hang-off tool.

US 1460402 describes a tubing spider håving two sections arranged to form a substantially cylindrical passage, and a rocking arm is carried by one of the sections and a gripping jaw is slidably mounted on the rocking arm.

US 8235104 Bl describes an apparatus for connecting or disconnecting a threaded connection of a first tubular member and a second tubular member at a wellhead. The apparatus has a frame movable between a first position adjacent the wellhead and a second position away from the wellhead. A first gripping member is connected to the frame and extending outwardly therefrom so as to apply a torque to the first tubular, and a second gripping member is movably connected to the frame so as to be movable between a first position away from the wellhead and a second position at the wellhead. The second gripping member is suitable for applying an opposing torque to the second tubular.

US 3690715 A describes a head subassembly for changing fuel cells in an atomic reactor. The subsassembly includes a plurality of hook-like fingers pivotally movable from a released into an engaged position locked beneath a downwardly-facing shoulder around the top of the cell. The fingers are cammed between their released and engaged positions by a pneumatic-servo-motor actuated cam plate. Each of the fingers is suspended from a separate sealed fluid chamber of variable volume and the several chambers are, in turn, serially interconnected to form a self-equalizing hydraulic system wherein the load is evenly distributed to maintain the cell in plumb relation.

US 4995763 A describes a freestanding offshore well structure håving a generally cylindrical caisson with a relatively small diameter drivepipe section connected to a larger diameter caisson section which is of sufficient strength to withstand wind and wave action. An upper portion of the drivepipe section is provided with a landing ring for a hanger for a conductor casing string or a wellhead body for a surface pipe string. A casing connector or nipple supports a diverter above the landing ring.

It is therefore a need for a hang-off tool that is more efficient in use, as well as being safer and easier to operate.

Summary of the invention

The invention is set forth andcharacterized inthe main claim, while the dependent claims describe other characteristics of the invention.

It is thus provided a hang-off tool for supporting an elongate object, said tool comprising a plurality of support units each håving a support member,characterized inthat the support members are movable between a stand-by state in which the elongate object is not supported by the tool, and an activated state in which the elongate object is supported by and hanging from the support members, and wherein the plurality of support units comprise respective fastening means configured for connecting the support units to a structure surrounding the elongate object, and wherein the support units are configured for abutment against an abutment member on the elongate object.

In one embodiment, the support members are movable by means of a respective hinge-connection to a footing, and the footing comprises the fastening means. The support members comprise in one embodiment a respective abutment member arranged in the region of the firee end of the support member.

In one embodiment, the abutment member is releasably connected to the support member and arranged to carry axial loads imposed by the elongate object.

In one embodiment, the support member comprises an abutment surface arranged in the region of the firee end of the support member and arranged to carry lateral loads imposed by the elongate object.

The support member comprises in one embodiment a lever arm configured to move the support member between the stand-by state and the activated state.

In one embodiment, the hang-off tool comprises at least three support units, removably connectable to the structure surrounding the elongate object.

The invented tool is particularly useful as a hang-off tool for suspending a pipe extending into a caisson; wherein the plurality of the support members are connected to a flange member on the caisson.

It is also provided a method of installing a pipe in a caisson by means of the hang-off tool according to the invention,characterized bythe steps of: a) attaching the support units to the caisson and arranging the support units in a stand-by state; b) lowering a first pipe section into the caisson; c) moving the support member on each of the support units to an activated state, and continue to lower the first pipe section until an abutment element on the first pipe section is being supported by the support members; d) connecting a second pipe section to the upper end of the first pipe section while the latter suspended by the support units; e) lifting the pipe sections sufficiently for the support members to be moved to the stand-by state, and then continue lowering the pipe sections into the caisson.

Brief description of the drawings

These and other characteristics of the invention will become clear from the following description of a preferential form of embodiment, given as a non-restrictive example, with reference to the attached schematic drawings, wherein: Figure 1 is a schematic figure showing a typical arrangement of a submerged pump on a ship, as discussed above in the section titled "Background of the invention"; Figure 2 is a perspective view of a prior art hang-off tool, as discussed above in the section titled "Background of the invention"; Figure 3 is a perspective view of an embodiment of the invented hang-off tool in use, supporting a pipe; Figure 4 is a perspective view of the same embodiment as in figure 3, but from a different perspective; Figure 5 is a perspective view corresponding to figure 3, but shows the hang-off tool in an open, or standby, position where the pipe is not supported; Figure 6 corresponds to figure 5, but the pipe has been removed; Figure 7 corresponds to figure 3, i.e. showing the hang-off tool in a closed (activated) position, but without the pipe; and Figure 8 is a perspective, and partly exploded, view of a support unit of the hang-off tool.

Detailed description of a preferential embodiment

The following description may use terms such as "horizontal", "vertical", "lateral", "back and forth", "up and down", "upper", "lower", "inner", "outer", "forward", "rear", etc. These terms generally refer to the views and orientations as shown in the drawings and that are associated with a normal use of the invention. The terms are used for the reader's convenience only and shall not be limiting.

Figure 3 shows the aforementioned pipe 11 being supported by the hang-off tool 24. The invented hang-off tool 24 comprises in the illustrated embodiment four support units 25, one of which is shown in figure 8.

Turning initially to figure 8, each support unit 25 comprises a footplate 14 configured for assembly and connection onto (via bolt holes 21) onto caisson flange 10 (see e.g. figure 7). A movable lug, also referred to as a rocker arm, 13 is hinge-connected via a support 16 and bolt 22 to the footplate 14. In the illustrated embodiment, the rocker arm 13 comprises a lever arm 15 (for manoeuvring the rocker arm) and an abutment member 18, releasably arranged on the rocker arm firee end via screws 20. The abutment member

18 may thus be replaced, if needed. The abutment member 18 comprises a first support surface 26, and a second support surface 19 is arranged in the region of the rocker arm firee end. Both support surfaces will be described below. Figure 7 shows four support units, labelled 25a-d, assembled on a flange 10 of a caisson 5 extending above a deck D. Each support unit 25a-d in connected to the caisson flange via bolts 21a. The support units are assembled at regular intervals around the flange 10, and are shown in an activated - or closed - state, i.e. each one of the rocker arms 13 have been rotated to an inward-pointing position. Figure 6 shows the same four support units 25a-d assembled on the flange 10, as in figure 7. However, here the support units are shown in a standby - or open - state, i.e. each one of the rocker arms 13 have been rotated to an upward-pointing position, allowing passage into and out of the caisson. Figure 5 also shows the support units 25a-d in the open position, and a water pipe 11 is extending into the caisson (suspended by structures not shown in the figure). Returning to figure 3, the four support units 25a-d are shown in the activated - or closed - state (i.e. the fourth support unit 25d is hidden behind the pipe). In this state, each of the support units 25a-d support the pipe 11 via the aforementioned abutment member 18. Each abutment member bears against a connection flange 12 on the pipe 11 and the pipe 11 (and the submerged pump attached to it, not shown) is effectively suspended by the four support units 25a-d.

The first support surface 26 of each abutment member 18 carries the axial (i.e. in the pipe-longitudinal direction) loads of the pipe 11. In one embodiment, each second support surface 19 is configured and dimensioned such that they abut against the pipe 11 and thus provide lateral (i.e. substantially normal with respect to the pipe longitudinal axis) support for the pipe 11.

Also, figure 3 clearly shows that the support units (i.e. the invented hang-off tool 24) do not interfere with piping 9 (for control wires, instrumentation, power cables, etc.) that is attached to the pipe 11.

In use, for example in installing a submerged pump 3 in a caisson 5, the invented hang-off tool 24 can be operated as follows:

1. Attaching the support units 25a-d to the caisson flange and arranging the support units in a stand-by (open) state (see figure 6); 2. Lowering the pump 3, attached to a pipe 11, into the caisson (see figure 5), hanging, for example by a crane (not shown); 3. Moving the rocker arm 13 on each of the support units to the activated (closed) state, and continue to lower the pipe until the pipe flange 12 is resting on (and thus being supported by) the rocker arms 13; 4. Disconnecting the crane (not shown) and connecting a new length of pipe 11' while the pipe 11 is hanging from the support units (see figure 3). 5. Reconnecting the crane (not shown) and lifting the pipes 11, 11' sufficiently for the rocker arms to be moved to the open (stand-by) state, and then continue lowering the pipes into the caisson.

The above steps are repeated until the submerged pump has reached its designated position, i.e. at the hull opening 23.

The invented hang-off tool 24 is an efficient tool for installing a submerged pump (and for repair, maintenance and replacement) that is connected to a pipe, extending in a caisson as shown. It should be understood, however, that the hang-off tool may be applicable for supporting (suspending) also other objects.

While the invention shall not be limited to a specific material, the support unit parts may conveniently comprise stainless steel of grade 316 or similar.

While the invention has been described with reference to an embodiment håving four support units 25 a-d, the invention is not limited to this quantity. The skilled person will understand that fewer and more support units are possible. An embodiment of the hang-off tool håving three support units spaced equi-distant around the caisson flange is conceivable.

The invented hang-off tool is easy and safe to use. Compared to the hang-off tools of the prior art, each support unit of the invented tool is much lighter, for example on the order 25 kg; a weight which is easily handled by an individual.

Claims

1. A hang-off tool (24) for supporting an elongate object (11), said tool comprising a plurality of support units (25a-d) each håving a support member (13),characterizedin that the support members (13) are movable between a stand-by state in which the elongate object is not supported by the tool (24), and an activated state in which the elongate object is supported by and hanging from the support members (13), and wherein the plurality of support units (25a-d) comprise respective fastening means (21, 21a) configured for connecting the support units to a structure (10) surrounding the elongate object, and wherein the support members (13) are configured for abutment against an abutment member (12) on the elongate object (11).

2. The hang-off tool of claim 1, wherein the support members (13) are movable by means of a respective hinge-connection to a footing (14), and the footing comprises the fastening means.

3. The hang-off tool of claim 1 or claim 2, wherein the support members (13) comprise a respective abutment member (18) arranged in the region of the free end of the support member.

4. The hang-off tool of claim 3, wherein the abutment member (18) is releasably connected to the support member and arranged to carry axial loads imposed by the elongate object.

5. The hang-off tool of any one of the preceding claims, wherein the support member (13) comprises an abutment surface (19) arranged in the region of the free end of the support member and arranged to carry lateral loads imposed by the elongate object.

6. The hang-off tool of any one of the preceding claims, wherein the support member (13) comprises a lever arm (15) configured to move the support member between the stand-by state and the activated state.

7. The hang-off tool of any one of the preceding claims, comprising at least three support units, removably connectable to the structure surrounding the elongate object.

8. Use of the hang-off tool of any one of claims 1-7, as a hang-off tool for suspending a pipe (11) extending into a caisson (5); wherein the plurality of the support members (25a-d) are connected to a flange member (10) on the caisson.

9. A method of installing a pipe in a caisson (5) by means of the hang-off tool of any one of claims 1-7,characterized bythe steps of: a) attaching the support units (25 a-d) to the caisson and arranging the support units in a stand-by state; b) lowering a first pipe section (11) into the caisson; c) moving the support member (13) on each of the support units to an activated state, and continue to lower the first pipe section until an abutment element (12) on the first pipe section is being supported by the support members (13); d) connecting a second pipe section (11') to the upper end of the first pipe section (11) while the latter suspended by the support units; e) lifting the pipe sections (11, 11') sufficiently for the support members (13) to be moved to the stand-by state, and then continue lowering the pipe sections into the caisson.