NO20180431A1

NO20180431A1 - Fingerboard latch arrangement

Info

Publication number: NO20180431A1
Application number: NO20180431A
Authority: NO
Inventors: Petter Mydland; Vegard Taxerås
Original assignee: Mhwirth As
Priority date: 2018-03-27
Filing date: 2018-03-27
Publication date: 2019-09-30
Also published as: GB2573395A; GB201904046D0

Description

FINGERBOARD LATCH ARRANGEMENT

The present invention relates to a fingerboard latch arrangement, including but not limited to such fingerboard latch arrangements used in fingerboards for holding a plurality of elongate pipes in drilling operations.

BACKGROUND

Various types of storage devices are used in offshore well operations, such as petroleum drilling, well intervention, subsea mining, or any similar operation, to store tools and equipment such that these are readily available when needed. In such operations, a string is commonly assembled topside by a plurality of segments which are successively connected to the string and lowered down towards a sea floor or down through a wellbore.

Tubular storage devices, such as fingerboards, on mechanized or automated handling systems are typically arranged as an array of horizontally extending fingerboards arranged in relation to a fixed permanent setback base. Latches, or locking fingers, are used to hold each tubular in place within the fingerboard. When a tubular section, for example a section of drill pipe, is to be removed from the fingerboard, the associated latches are opened such as to allow a pipe handling machine to remove the tubular from the fingerboard. Similarly, when a tubular is placed in the fingerboard for storage, the latches associated with that storage slot is brought to a locking position in order to secure the tubular in the fingerboard.

Patent publications US 2016/0168929 A1, CN204186313U, WO 01/79651 A1, WO 2009/082197 A2, WO 2013/141697 A2, WO 2016/076920 A2 and US 2016/0076920 A1 show examples of known fingerboard assembly configurations.

During operations, it is of high importance that the fingerboard function properly. For example, it is important that, when a tubular is placed in the fingerboard, the latches close securely in order to avoid the tubular from falling out of the fingerboard.

Similarly, when a pipe handling machine is operated to remove a tubular from the fingerboard, it is important that the latches open reliably to release the tubular from the storage position. Failure of the fingerboard to function properly may lead to serious accidents, for example during drilling operations with staff working in the drill floor area, as well as damage to equipment and machines.

There is therefore a need for improved techniques and solutions to ensure the functionality and reliability of fingerboards and similar storage arrangements. The present invention has the objective to provide such improvements, or to provide other advantages compared to known solutions.

SUMMARY

In an embodiment, there is provided a latch actuator for a fingerboard, the actuator comprising a housing with a fluid inlet and a piston slidably mounted in the housing and movable in response to a fluid pressure applied via the fluid inlet, wherein the piston comprises a lock surface and wherein the actuator further comprising a lock piston movable between a first position in which the lock piston engages the lock surface and a second position in which the lock piston does not engage the lock surface.

In an embodiment, there is provided a fingerboard latch assembly comprising a latch and an actuator, wherein the piston is connected to the latch for moving the latch between an open position and a closed position.

In an embodiment, there is provided a fingerboard comprising a plurality of fingers and a plurality of fingerboard latch assemblies.

The following detailed description and the appended dependent claims outline further embodiments according to the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

Various characteristics will become clear from the following description of illustrative embodiments, given as non-restrictive examples, with reference to the attached drawings, in which

Fig.1 shows a fingerboard according to an embodiment,

Figs 2 and 3 show a fingerboard latch with a latch actuator according to an embodiment,

Fig.4 shows an embodiment of a latch actuator of a fingerboard.

DETAILED DESCRIPTION

Embodiments of the present invention relate to a latch actuator for a fingerboard latch arrangement, including but not limited to such fingerboard latch arrangements used in fingerboards for holding a plurality of elongate pipes in drilling operations, comprising a housing with a pressure inlet, wherein a piston is slidably mounted in the housing in axial direction. In this embodiment and in the following description, the latch actuator is a hydraulic latch actuator, however it may equally well be a pneumatic latch actuator and the actuator can be operated with any suitable hydraulic or pneumatic fluid.

The hydraulic actuator further comprises a spring, which is in operative connection with the piston, returning the piston to its starting position when the pressure supplied to the pressure inlet is removed. The hydraulic actuator comprises a blocking element, which can be inserted, for example, into a recess of the piston such that an axial movement of the piston is blocked. Blocking the piston prevents the hydraulic actuator from an unwanted actuation of one of the latches, so that the drilling pipes do not fall out of the fingerboard or get stuck. Therefore the hydraulic actuator prevents the fingerboard and the drilling pipes from damage and allows a smooth and error free handling of the elongate pipes by a pipe handling machine.

In a preferred embodiment the blocking element comprises a lock piston and a spring, pushing the lock piston into a recess of the piston, when the pressure supply to the hydraulic actuator is stopped or reduces below a certain treshhold value. By a spring-loaded blocking element the lock piston can be pressed into the recess of the piston in a simple and reliable manner. In this case, the spring is preferably formed as a spiral spring, which is accommodated on a shoulder of the locking piston.

In a preferred embodiment the housing comprises a front head, a central part, preferably a barrel, and a rear part. By a split housing a particularly simple installation of the hydraulic letch actuator is possible. Furthermore, the manufacturing of the individual components can be simplified, whereby the manufacturing costs decrease. In addition, different materials can be selected for the individual components of the housing, whereby additional degrees of freedom arise in the design of the hydraulic actuator.

Optionally, the hydraulic actuator comprises a pressure inlet and a pressure outlet, wherein the pressure inlet is formed on an axial face of the rear head and the pressure outlet is formed on a lateral surface of the rear head. By a housing having a pressure inlet and a pressure outlet the pressure supply to the piston can be improved. Preferably a throttle is provided in the pressure outlet, which allows a pressure reduction independently of the pressure supply at the pressure inlet. In this way it can be avoided that a piston remains pressurized and a blocking of the piston is not possible, although the pressure supply at the pressure inlet is stopped.

Optionally, the rear head, the center part and the front head are fixed together by tightening means. To achieve an easy assembling of the housing it is useful to have tightening means fixing the front head, the center part and the rear head of the housing. The front head may have a receiving surface for picking up the center part, and the center part or the rear head may have another receiving surface, so that the housing parts can be put together easily and tightened by fixing the rear head.

In another embodiment, a pressure chamber is formed in the housing, preferably in the rear part of the housing. With a pressure chamber, a uniform pressure on the piston can be exerted in a simple manner, whereby the risk of tilting or jamming of the piston is reduced.

Optionally, the blocking element has a groove or an orifice, hydraulically connecting the pressure chamber with a pressure outlet of the housing. Through a bore or a groove on the blocking piston, a throttle can be formed in a simple manner, which connects the pressure chamber with the pressure outlet. In this way, a pressure reduction in the pressure chamber is possible when the pressurization of the hydraulic actuator is reduced or stopped, so that the blocking piston can easily enter into the recess of the piston to avoid axial movement of the piston.

In an embodiment, the spring is compressed when an end of piston facing the pressure chamber is applied with hydraulic pressure. If the spring is compressed when the piston is pressurized, the piston moves in the axial direction and pushes the push rod out of the housing so that the corresponding latch of the fingerboard is opened. The spring is tensioned, so that the spring pushes the piston back into the starting position when the pressure to the piston is reduced or off. Alternatively, the piston can also be brought back by a tension spring in the starting position, which is lengthened accordingly when the piston is pressurized.

In an embodiment, the end of the piston facing the pressure chamber carries a piston seal. The piston seal seals the piston against the housing, so that the pressure medium does not penetrate into the mechanics of the piston. As a result, a pressure reduction can be avoided and the function of the piston can be improved. Furthermore, it can be prevented that the pressure medium exits at the junctions between the housing components when the piston seal is guided exclusively in the rear head of the housing.

Optionally, a guide bushing is inserted in the front head of the housing. A guide bushing can further improve the guidance of the piston and avoid jamming or tilting of the piston when the piston is sliding in axial direction.

An end of the piston facing the front head of the housing can be connected to a push rod or forming a push rod operating a latch of a finger of a fingerboard. For operating the latch of the fingerboard, the push rod is pushing against a mechanism of the latch, so that the latch is opened or closed safely and can be locked in the opened or closed position by blocking any further axial movement of the piston or the push rod.

The housing may have a recess, wherein a cover is inserted, carrying the blocking element. The blocking element can easily be installed in a recess of the housing by a cover which is fixed at the housing by fixing means, e.g. by a screw or a bolt.

The housing may have a centric orifice, wherein the piston is guided in the centric orifice by a wear ring. To avoid wear at the housing or at the piston a wear ring can be attached at the piston, using a material softer than the material of the housing or the piston, so that there is wear only at the wear ring. This enables an easy service on the fingerboard, wherein the wear rings of the hydraulic latch actuator is changed and the other components can be cleaned and used again.

Optionally, the piston is a multi-part piston comprising a first piston and at least a second piston, wherein the second piston is fixed to an end surface of the first piston. A multi-part piston allows, for example, to use different materials for the different sections of the piston. In this way, each section can be optimized to e.g. reduce weight, corrosion or wear, and to extend the lifetime of the hydraulic latch actuator.

In an embodiment, the first piston can be made of aluminum and the second piston can be made of a stainless steel. Using stainless steel for the blocking section of the piston is an advantage, as the blocking section needs to be hard on the one hand side, to avoid wear and must stand the hydraulic medium used for the pressure supply to avoid corrosion or damages caused by the pressure medium.

The various embodiments and features of the invention mentioned in this application are, unless otherwise stated, advantageously freely combinable with each other.

Embodiments of the present invention may relate to storage of drill pipes, casing, bottom hole assemblies, risers, or any elongate tool that is needed on an offshore drilling or well intervention vessel or in any kind of subsea operation using tubular shaped tools. Other examples for which the present invention may be suitable for use include research vessels, geothermal drilling, deep sea mining etc.

Figure 1 shows a fingerboard 1 suitable for use on e.g. drilling rigs. The fingerboard 101 has a plurality of fingers 102-106, i.e. parallel elongate support members defining storage spaces between them, in which sections of drill pipe 108 or other tubular members may be stored. The plurality of fingers 102-106 are arranged in a horizontal plane defined by the fingers 102-106. The fingerboard 101 further comprises a large number of latches 107, each latch 107 being fixed to a finger 102-106 such as to define a large number of storage slots defined by the fingers 102-106 and the latches 107.

The latches 107 are actuated by means of a hydraulic latch actuator 20 (not visible in Fig.1; see Figs 2-3), so that a given latch 107 can be opened when a tubular is being removed from the fingerboard 101 by a pipe handling machine (not shown), or when a tubular is placed in the fingerboard 1 for storage. The latch actuators 20 have an actuating rod which connects to the latch 107 by means of a pivot mechanism, as shown in Figs 2 and 3.

Fig. 4 shows details of a hydraulic latch actuator 20 according to an embodiment. The hydraulic latch actuator 20 comprises a push-rod 1 which is connected to the respective latch 107 such that when the push-rod 1 is in the retracted position (as in Fig. 2), the latch 107 is in the closed position and when the rod 1 is in the advanced position (as in Fig.3), the latch 107 is in the open position. The hydraulic latch actuator 20 has a housing 21 which comprises a front head 2, a center part 17 and a rear head 12. The housing 21 has a centric orifice in which a piston 8 is arranged.

The front head 2, has a first axial front face with an opening through which the pushrod 1 passes. The front head 2 has a stepped center bore, wherein a guide bushing 4 guiding the piston 8 and a scraper 3 are positioned in a first section of the stepped center bore. On a lateral surface of the front head 2 a silencer 5 is arranged, connecting the central bore of the housing 21 with the environment allowing a fluid to stream into or off the centre bore when piston 8 is moved in axial direction.

A guidance section is formed on a lateral surface of the front head, holding the center part 17 of the housing 21, especially a barrel 17 of the housing 21, in position, when the center part 17 is mounted on the front head 2. The center part 17 has a cylindrical shape and is guided by another guide section on a lateral surface of the rear head 12 of the housing 21.

The rear head 12 has a pressure inlet 18 to apply a pressure medium, such as an oil, to the hydraulic latch actuator 20. A pressure chamber 23 is formed in the read head 12 of the housing, applying pressure to the piston 8 or a second piston 25 connected to the first piston 8. The rear head 12 has a recess 24 on its lateral surface into which a cover 13 is inserted. The cover 13 is fixed at the rear head 12 via fixing means, such as a screw 14, that allows to detach the cover 13 from the rear head 12. The cover 13 has a receiving space for a blocking element 22 which is operable to block axial movement of the piston 8, 25 and to lock the piston 8, 25 in its non-actuated position, as illustrated in Fig.4.

The piston 8 can be a one piece piston 8 or a multi-part piston 1, 8, 25, comprising a push-rod 1, a first piston part 8 and a second piston part 25, fixed at an front face of the first piston 8. For example, the second piston 25 can be screwed on a thread of the first piston 8. The piston 8 in this embodiment comprises a wear ring 9 and a piston seal 10. A receptacle for a first end of a spring 6 is formed on the piston 8. The second end of the spring 6 is received at a step of the stepped bore of the front head 2. Additionally a guide 7 for the spring is mounted on the piston 8 to keep the spring 6 in position and avoid jamming or twisting of the spring 6.

On the piston 8, in this embodiment at the second piston part 25 or a section of the first piston 8 facing the pressure chamber 23 there is a recess 11. The recess 11 may be formed in a turning process reducing the diameter of the piston 8, 25 in said section. The recess defines a lock surface 31, in this embodiment on the rear side wall of the recess. The lock surface 31 may, alternatively, be provided on a stepped section of the piston 1, 8, 25 if no recess 11 is used. The lock surface 31 in this embodiment is substantially perpendicular to the axial direction of the piston 1, 8, 25, however the lock surface 31 may alternatively be angled.

The blocking element 22 comprises a lock piston 15 and a spring 16. The lock piston 15 is in fluid contact with the pressure chamber 23 and inlet 18, and is movable by means of fluid pressure from the pressure chamber 23 between a first position in which the lock piston 15 engages the lock surface 31 and a second position in which the lock piston 15 does not engage the lock surface 31. The spring 16 configured to push the lock piston 15 into the recess 11 of the piston 8, 25 when no pressure is supplied to the pressure chamber 23, such that when the latch actuator 20 is in the “latch closed” position (see Fig.2), the lock piston engages the lock surface 31 and prevents the piston 1, 8.25 from moving the latch 107 to the open position. Fig.4 thus shows the hydraulic latch actuator 20 in a block situation, when no pressure is applied to the pressure inlet 18 and the piston 8 is blocked by the lock piston 15 in its starting position. The lock piston 15 may be movable radially in relation to the axial direction of the piston 1, 8, 25, or the direction of motion may be at a different angle.

When the latch 107 is to be opened, a fluid pressure is applied to inlet 18, whereby the lock piston 15 will be pushed radially outwardly into its second position where it does not restrict the movement of piston 1, 8, 25. The fluid pressure in pressure chamber 23 then continues to actuate the piston 1, 8, 25 such as to open the latch 107. When the fluid pressure is released, the spring 6 pushes the piston 1, 8, 25 back into its “latch closed” position, and the spring 16 brings the lock piston 15 back into engagement with the lock surface 31.

In this manner, the latch 107 is secured from opening inadvertently when there is no fluid pressure applied to the inlet 18. For example, even if a pipe would engage the latch 107 externally and provide an upwards acting force on the latch 107, the blocking element 22 would keep the latch 107 in its closed position.

ITEM DESCRIPTION

1 Rod 18 Pressure inlet

2 Front head 19 Pressure outlet

3 Scraper 20 Hydraulic actuator

4 Guide bushing 21 Housing

5 Silencer 22 Blocking element

6 Spring 23 Pressure chamber

7 Guide for spring 24 Recess

8 Piston 25 second piston

9 Wear ring 101 Fingerboard

10 Piston seal 102 Finger

11 Recess 103 Finger

12 Rear head 104 Finger

13 Cover 105 Finger

14 Screw 106 Finger

15 Lock piston 107 Latch

16 Spring 108 Drill pipe

17 Barrel / center part

The invention is not limited by the embodiments described above; reference should be had to the appended claims.

Claims

1. A latch actuator (20) for a fingerboard (101), the actuator (20) comprising a housing (21) with a fluid inlet (18) and a piston (1,8,25) slidably mounted in the housing (21) and movable in response to a fluid pressure applied via the fluid inlet (18),

wherein the piston (1,8,25) comprises a lock surface (31) and wherein the actuator (20) further comprising a lock piston (15) movable between a first position in which the lock piston (15) engages the lock surface (31) and a second position in which the lock piston (15) does not engage the lock surface (31).

2. A latch actuator according to claim 1, wherein the lock surface (31) is arranged in a recess (11) of the piston (1,8,25) and the lock piston (15) is operable to move into and out of the recess (11).

3. A latch actuator according to claim 1 or 2, wherein the lock piston (15) is in fluid contact with the fluid inlet (18) and is movable between the first position and the second position in response to fluid pressure applied via the fluid inlet (18).

4. A latch actuator (20) according to any preceding claim, comprising a spring (16) arranged to urge the lock piston (15) towards its first position.

5. A latch actuator (20) according to any preceding claim, comprising a fluid chamber (23) is formed in the housing (21) and fluidly connected to the fluid inlet (18).

6. A latch actuator (20) according to any of the preceding claims, wherein the housing (21) has a body recess (24) in which the lock piston (15) is arranged and wherein a cover (13) is arranged to fix the lock piston (15) in place in the body recess (24).

7. A latch actuator (20) according to any preceding claim, wherein the piston (1,8,25) is a multi-part piston comprising a push-rod (1), a first piston part (8) and a second piston part (25).

8. A latch actuator (20) according to claim 7, wherein the first piston part (8) is made of aluminium and the second piston part (25) is made of steel.

9. A latch actuator (20) according to any preceding claim, wherein the lock surface (31) is substantially perpendicular to an axial direction of the piston (1,8,25).

10. A latch actuator (20) according to any preceding claim, wherein the lock piston (15) is movable substantially perpendicularly to an axial direction of the piston (1,8,25).

11. A fingerboard latch assembly comprising a latch (107) and an actuator (20) according to any preceding claim, wherein the piston (1,8,25) is connected to the latch (107) for moving the latch between an open position and a closed position.

12. A fingerboard (101) comprising a plurality of fingers (102-106) and a plurality of fingerboard latch assemblies according to the preceding claim.