GRIPPING DEVICE FOR HANDLING EQUIPMENT WITH A DRILL STRING

Abstract

A gripping device is adapted for handling equipment with a drill string, wherein an annular actuator housing includes a hydraulically activated, rotatable cam disc which is arranged to displace a number of locking slides from a first position, in which the locking slides are retracted into the actuator housing, and a second position, in which the locking slides are in engagement with the drill string extending through a center opening in the gripping device, by abutting against a shoulder of a tool joint in the drill string. The gripping device is connected to a hydraulic supply and return for the actuation of the cam disc via a hydraulic coupler in a connection port on the actuator housing. Alternatively pressurizing and ventilating two adjacent actuation volumes in the cam disc brings about rotation of the cam disc within a sector of the cam disc.

Claims

1. A gripping device adapted for handling equipment with a drill string, the gripping device comprising an annular actuator housing having a hydraulically activated, rotatable cam disc which is arranged to displace a number of locking slides from a first position, in which the locking slides are retracted in-to the actuator housing, and a second position, in which the locking slides are in engagement with the drill string extending through a center opening in the gripping device, by abutting against a shoulder of a tool joint in the drill string, wherein the gripping device is connected to a hydraulic supply and return for the actuation of the cam disc via a hydraulic coupler in a connection port on the actuator housing, and wherein alternately pressurizing and ventilating two adjacent actuation volumes in the cam disc brings about rotation of the cam disc within a sector of the cam disc.

2. The gripping device according to claim 1, wherein the locking slides are provided with dynamic seals.

3. The gripping device according to claim 1, wherein the hydraulic coupler is arranged externally on a receiver unit in the open sea, or externally on a riser, and includes a hydraulic actuator which is arranged to move the hydraulic coupler into or out of a connection port in the actuator housing through an opening in the receiver unit or the pipe surrounding the gripping device.

4. The gripping device according to claim 1, wherein a spring-loaded peg is arranged to engage with a first or a second recess in the cam disc and hold the cam disc in position, when the locking slides have been pushed out into the second position and when the locking slides are in the first position, respectively.

5. The gripping device according to claim 1, wherein the locking slides are provided with check valves which, via bores, are arranged to let liquid through from a rear side of the locking slides when the locking slides are being returned to the first position.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In what follows, an example of a preferred embodiment is described, which is visualized in the accompanying drawings, in which:

[0020] FIG. 1 shows, in perspective, a gripping device with handled equipment fixed to it, in an outer pipe, with a drill string through the center opening of the actuator housing.

[0021] FIG. 2 shows, in perspective, the gripping device externally, with locking slides in the outer position.

[0022] FIG. 3 shows a horizontal section through the gripping device, with locking slides in the inner position in FIG. 3A and in the outer position in FIG. 3B.

[0023] FIG. 4 shows a vertical section through a locking slide in a first, retracted position.

[0024] FIG. 5 shows a horizontal section through a locking slide in the outer position.

[0025] FIG. 6 shows a horizontal section through a hydraulic coupler and a hydraulically operated cylinder which moves the coupler into or out of the actuation port in the housing.

[0026] FIG. 7 shows a horizontal section through a plate dividing the actuation chamber into two separate volumes, an external flange for attaching the dividing plate to the actuator housing, a connection port, and inner bores in the dividing plate for pressurizing and ventilating the actuation volumes.

DETAILED DESCRIPTION OF THE DRAWINGS

[0027] Reference is first made to FIG. 1, in which the reference numeral 1 indicates a gripping device fixed to equipment 10 which is arranged to be handled by means of a drill string 5 by connection via the gripping device 1. Here, the gripping device 1 and the equipment 10 are shown to have been lowered into and positioned in a riser 9.

[0028] Reference is now made to FIGS. 2, 3A, 3B, 4 and 5. An annular actuator housing 2 with a top plate 2A is provided with a number of locking slides 3 surrounding a center opening in the gripping device 1. The locking slides 3 are kept inside the actuator housing 2 when a hydraulically activated, rotatable cam disc 4, which is in movable engagement with the locking slides 3, is in a position rotated back, as shown in FIG. 3A. In the exemplary embodiment, there is a differential pressure between a static pressure in the riser 9 (see FIG. 1) and an external sea-water pressure, causing retraction of the locking slides 3. Alternatively, the locking slides 3 may be pushed back mechanically, for example by spring force (not shown).

[0029] FIGS. 4 and 5 show a cross-cut locking slide 3 which is provided, here, with a check valve 3A which, via a bore 3B, will let liquid through from a rear side of the locking slide 3 to prevent blocking of the locking slide 3 by an enclosed liquid volume at the rear side of the locking slide 3, for example by the use of volume compensation (not shown). As the cam disc 4 is rotated forwards, the outer ends of the locking slides 3 are pushed out into the center opening of the housing 2 and grip loosely around the drill string 5, as shown in FIG. 3B. The locking slides 3 are provided with through pins 3C (see FIG. 4) forming end stops for the locking slides 3 in the outer position. Upper and lower edges of the outer ends of the locking slides 3 are formed with bevels 3D for abutment against upper and lower conical shoulder portions, respectively, of a tool joint 5A of the drill string 5. Dynamic seals 3E around the locking slides 3 form a sealing partition between the medium in the center opening of the actuator housing 2 and the enclosed and possibly volume-compensated medium at the rear side of the locking slides 3.

[0030] In the actuator housing 2 of the gripping device 1, a spring-loaded peg 6 is arranged (see FIGS. 3A and 3B), which, with an end portion, enters one of two recesses at the outer edge of the cam disc 4 and holds the cam disc 4 in place, as the locking slides 3 have been moved into the outer position and when the locking slides 3 are in the retracted position, respectively. By means of a spring (not shown) on the peg 6, the end portion is held in place in one of the recesses on the edge of the cam disc 4. The peg 6 is forced back against the spring and out of the recess as the cam disc 4 is rotated away from an end position by hydraulic actuation.

[0031] An actuation chamber comprises two actuation volumes 4A, 4B which are separated by a dividing plate 7A in a recess in a sector along an outer edge of the cam disc 4, and the actuation volumes 4A, 4B are pressurized and ventilated, respectively, depending on the desired direction of rotation of the cam disc 4. The dividing plate 7A is provided with an external flange 7B and projects in through an opening in a recess in the outer wall of the actuator housing, to which the flange 7B is screwed. The dividing plate 7A forms a sealing partition between the actuation volumes 4A, 4B in the recess in the cam disc 4, which is surrounded by a seal (not shown) against the inside of the outer wall of the actuator housing 2.

[0032] From the outside of the flange 7B, there is a connection port 7C with a bore into the dividing plate 7A. A hydraulic coupler 8A has been inserted into the bore by means of a hydraulically operated cylinder 8B for connecting and disconnecting the coupler 8A. The cylinder 8B will be arranged externally on a receiver unit in the open sea (not shown), or externally on the riser 9. This is shown in a simplified manner in FIG. 1 in the form of a section of the riser 9. In case a riser application is concerned, the passage in the pipe wall will be provided with a seal against the outer environment.

[0033] Farthest inwards in the bore from the connection port 7C, lateral outlets to the actuation chambers 4A, 4B have been placed, for alternately pressurizing and ventilating the liquid volumes, depending on the direction of rotation of the cam disc 4. There is hydraulic communication between external hydraulic hoses 8C, 8D and the actuation volumes 4A, 4B via bores in an external handle 8E on the coupler 8A and longitudinal bores through the coupler 8A, discharging into lateral outlets which are arranged to correspond with the lateral outlets of the dividing plate 7A to the actuation volumes 4A, 4B. The hydraulic connections between the lateral outlets in the dividing plate 7A and the coupler 8A, respectively, to the actuation chambers 4A, 4B are separated by means of annular seals externally on the coupler 8A.

[0034] In the case of emergency, there is a possibility of manual connection or disconnection of the coupler 8A by means of the external handle 8E, which is adapted for operation by an underwater vehicle (ROV). For the coupler 8A to be moved manually, the hydraulic lines of the cylinder 8B must be ventilated, typically by being severed.

[0035] It should be noted that all the above-mentioned embodiments illustrate the invention, but do not limit it, and persons skilled in the art may construct many alternative embodiments without departing from the scope of the attached claims. In the claims, reference numbers in brackets are not to be regarded as restrictive. The use of the verb to comprise and its different forms does not exclude the presence of elements or steps that are not mentioned in the claims. The indefinite article a or an before an element does not exclude the presence of several such elements.

[0036] The fact that some features are indicated in mutually different dependent claims does not indicate that a combination of these features cannot be used with advantage.