Traveling Loading Arm for Marine Tankers

1. Field of the Invention

This invention relates to articulated marine loading arms, and more particularly to loading arms movable across the deck of a tanker to facilitate loading the tanker from either side.

2. Description of the Prior Art

The production of oil and gas from offshore wells has developed into a major endeavor of the petroleum industry, and this growth has fostered extensive interest and investigation into means for transporting the produced fluids to shore-based refineries or storage facilities. Although in many instances pipelines are employed for this purpose, more and more wells are being drilled and completed in deep water locations where the use of marine tankers of very large capacity constitutes the most practical and efficient transportation method, such as where pipelines would be too costly or too difficult to construct.

One of the more common types of offshore loading facilities includes a buoy or other floating platform to which the tanker may be moored while loading, and to which are connected a number of flexible hoses for transferring fluid between the buoy or platform and the tanker. The flexible hoses may be either floating on the surface of the water or submerged beneath the surface, and are usually provided with a tag line to enable the end of the hose to be picked up and pulled over the side of the tanker for connection to the tanker manifold.

Because of their large size these hoses are actually quite stiff, cumbersome, and not well adapted to bend in a tight radius, and therefore exertion of a substantial tension on the end of the hose is required in order to flex it over the side of the vessel and bring it to the manifold port. Such progressive flexing of the hose can abrade and seriously weaken it, thereby reducing its service life and also creating a real danger of possible rupture and spillage of the petroleum or other fluid being transferred.

What is needed is a means to connect the hose in an unbent vertical attitude to the tanker manifold. It also is desirable that the hose can be connected on either side of the ship to the apparatus which transports the fluid between the end of the hose and the tanker manifold port.

The present invention comprises a traveling loading arm for mounting on the deck of a marine tanker for transferring fluid from a hose on either side of the tanker to manifold ports mounted on the tanker deck. This invention overcomes some of the disadvantages of the prior art by employing a pair of lengths of pipe pivotally joined together to form an articulated pipe assembly which can be extended over the side of the tanker and can be connected to a petroleum transfer hose without bending the hose over the tanker's railing. The articulated pipe assembly is mounted on a support carriage at either end and the carriages are movably mounted on a set of support rails so that the pipe assembly can be moved to a position with one end of the assembly extending over one side of the tanker and the other end connected to one of the several manifold ports located amidship. The pipe assembly can be quickly moved along the support rails and the ends of the assembly secured in position, so that the tanker can be loaded or unloaded from either the port or the starboard side.

The inboard end of the pipe assembly can be quickly disconnected from one of the manifold ports and connected to another manifold port without the need for disconnecting the outboard end from the petroleum transfer hose. The present invention allows the different holds of the tanker to be filled from a petroleum transfer hose positioned on either side of the tanker without changing the transfer hose, and allows the tanker manifold ports to be positioned amidship without any permanently connected pipes between the manifold ports and the sides of the tanker.

When the loading operation is completed the end of the pipe assembly which was connected to the petroleum transfer hose, can be disconnected from the hose and connected to one of the tanker manifold ports for storage and for draining the petroleum from the pipe assembly into the tanker's hold. The traveling loading arm can be moved across the tanker's deck in the manner of an inchworm by locking the brakes on a first one of the carriages at the end of the articulated arm and moving the second carriage to position the second end of the articulated arm adjacent the first end of the articulated arm. The brake on the second carriage can then be locked and the first carriage moved to place the articulated arm in the desired position.

FIG. 1 is a plan view of a traveling loading arm mounted on the deck of a marine tanker according to the present invention.

FIG. 2 is a side elevation of the traveling loading arm of FIG. 1.

FIG. 3 is an enlarged side elevation of one end of the arm of FIG. 2.

FIG. 4 is a plan view of the end of the arm shown in FIG. 3.

FIG. 5 is an enlarged side elevation of a second embodiment of one end of the traveling loading arm.

FIGS. 6-9 are schematic side elevations of the traveling loading arm of FIG. 1, showing a sequence of operation.

A traveling loading arm according to the present invention comprises an articulated pipe assembly 10 (FIGS. 1, 2, 6-9) supported at either end by a support carriage 11a, 11b movably mounted on a pair of support rails 12a, 12b (FIG. 1) or other suitable support structure. The support rails 12a, 12b are mounted transversely on a deck 15 of a marine tanker 16 to facilitate easy movement of the loading arm across the tanker's deck.

The articulated pipe assembly 10 includes a pair of lengths (FIGS. 1 and 2) of pipe 17a, 17b pivotally connected together at the ends by a swivel joint 20 and by a pair of pipe elbows 21a, 21b (FIG. 1). The left end portion of the pipe assembly 10 includes a pair of pipe elbows 22a, 23a (FIGS. 1,4) interconnected by a pair of swivel joints 26a, 27a and by a T-section of pipe 28a. The T-section 28a includes a flange 29a (FIG. 4) for connection to the tanker's manifold port.

Another swivel joint 31a connects a spool flange 32a to the pipe elbow 23a. A counterweight 33 (FIGS. 1, 4, 5) counterbalances the weight of the swivel joint 31a and the spool flange 32a about the axis of the swivel joint 27a. The right end portion of the pipe assembly 10 (FIG. 1) similarly includes a plurality of pipe elbows 22b, 23b, a pair of swivel joints 26b, 27b, a spool flange 32b and a T-section 28b. Each end of the articulated pipe assembly 10 can be connected either to a petroleum transfer hose or to a tanker's manifold port. The T-section 28a, 28b can be connected to any of the tanker's manifold ports while either of the spool flanges 32a, 32b can be connected to a petroleum transfer hose. When the flange 29a of the T-section 28a is not connected to either a manifold port or to a dummy flange, a cover plate (not shown) must be secured to the flange 29a to prevent leakage of fuel from the T-section. A cover plate must also be secured to the spool flanges 32a, 32b to prevent leakage when either of these flanges is not connected to a petroleum transfer hose.

Power to manipulate the articulated pipe assembly 10 is provided by a hydraulic cylinder 39 (FIGS. 1 and 2) which is connected by a pin 40 to a bracket 41. The bracket 41 is welded or otherwise connected to the length of pipe 17a and a piston rod 44 of the hydraulic cylinder is connected by a pin 45 and an ear 46 to the swivel joint 20. The ear 46 is welded or otherwise connected to an outer portion 20b of the swivel joint 20 with the outer portion 20b being welded to the end of the elbow 21b. When the piston rod 44 is extended from the cylinder 39, the spool flanges 32a, 32b of the pipe assembly 10 are moved closer together and the pipe assembly folds toward the position shown in FIG. 7. When the piston rod 44 is retracted into the cylinder 39, the flanges 32a, 32b of the pipe assembly are moved farther apart and the pipe assembly 10 moves toward the position shown in FIG. 8.

Each of the support carriages 11a, 11b includes a plurality of support wheels 35 (FIGS. 1-5) rotatably connected to support a box-like body member 36. Adjacent each of the wheels is a braking device 49 (FIGS. 2 and 5) mounted to the body member 36 and with the device 49 selectively pressed against the wheels 35 to prevent the wheels from rotating. A winch 50 (FIGS. 2 and 3) having a cable 51 with a hook 52 attached at the end thereof is mounted at the end of the body member 36 for connection to an eye 53 attached to the end of a petroleum transfer hose 56 to enable the support carriage to lift the petroleum transfer hose 56 (FIGS. 2 and 3) from the water and into position for coupling to the end of the articulated pipe assembly 10. The upper end of the hose 56 includes a flange 57 for connection to the spool flange 32a (FIGS. 2 and 3) of the pipe assembly 10, with the connection being made by a hydraulic coupler (not shown) or by bolting the flanges 57 and 32a (FIG. 4) together.

Each of the supporting carriages 11a, 11b includes a pair of hydraulic jacks 58 (FIGS. 1, 3 and 4), with each of the jacks connected to a side wall 61 of the body member 36 and each connected to a pivot pin 62. The pivot pins 62 are each welded to one of the pipe elbows 22a, 22b, 23a, 23b so that the hydraulic jacks can raise or lower the pipe elbows and the T-sections 28a, 28b relative to the carriage wheels 35. A slot 63 (FIG. 3) in each of the side walls 61 limits the vertical travel of the pivot pins 62. A plurality of hydraulic couplers 66 (FIGS. 1, 2, 4 and 5) mounted on the lower portion of the T-section 28 secure the T-section to any one of a plurality of tanker manifold ports 67a-67d for loading or unloading petroleum or they can secure the end of the traveling loading arm to a dummy flange 68a, 68b. The manifold ports 67a-67d are connected to the various tanker holds while the dummy flanges 68a, 68b (FIGS. 6-9) are each mounted adjacent the ship's railing 71 on the support rails 12a, 12b by a plate 72 (FIGS. 2 and 5) which is welded or otherwise connected between the support rails 12a, 12b and one of the dummy flanges 68a, 68b. The dummy flange holds the outboard end of the loading arm in position for connection to the petroleum transfer hose.

The support rails 12a, 12b are secured just above the ship's railing 71 by a plurality of support members 73 (FIGS. 2, 5-9) to facilitate extending the outboard end of the support carriages 11a, 11b over the side of the tanker for easy connection to the petroleum transfer hose 56. A plurality of cross braces 74 (FIG. 1) are connected between the rails 12a, 12b to insure uniform spacing between the rails. An additional pair of hose drum support rails 76a, 76b (FIG. 1) are mounted parallel to the support rails 12a, 12b to provide support for a pair of hose drum carriages 77a, 77b (FIG. 1). Each of the hose drum carriages include a spring loaded drum 78a, 78b (FIGS. 1 and 2) connected to a pair of sidewalls 81a, 81b by a rod 82 (FIG. 2) and supported by a plurality of wheels 83 for movement over the rails 12a, 76a or 12b, 76b. The rails 12a, 12b are used for the support carriages 11a, 11b and for one half of the support of the hose drum carriages 77a, 77b.

The hose drum carriage 77b takes up the slack in a hydraulic control line 86b (FIGS. 1 and 2) which is connected between the support carriages 11a, 11b. The hydraulic line 86b provides hydraulic fluid under pressure to control the hydraulic winches 50a, 50b from a control console (not shown) which can be located on either of the carriage 11a, 11b. Additional hydraulic control lines can be added to control additional devices, for example, a hydraulic control line may be needed to control the operation of the hydraulic couplers 66. When the articulated pipe assembly is in the extended position (FIGS. 2 and 8) the hydraulic line 86b is unrolled from the drum 78b with the hydraulic line taut enough to be suspended above the tanker deck 15. When the articulated pipe assembly 10 is moved into a stored position (FIG. 7) the spring loaded drum 78b rotates to roll the hydraulic line 86b about the drum and keep the hydraulic lines from tangling along the tanker's deck 15.

An electrical cable 87b (FIG. 2) connected between the hose drum carriage 77b and a take up spool 88b provides electrical power to operate a brake (not shown) to prevent undesired movement of the hose drum carriage 77b along the rails 12b, 76b (FIG. 1). The cable 87b is threaded over one of the idler pullys 91 which are connected to the rail 12b and is connected to the underside of the carriage 77b. The take up spool 88b is also rotatably connected to the support rail 12b by a bracket 92 (FIG. 2) and is mounted near the center line of the tanker to provide convenient brake control signals to the hose drum carriage when the traveling loading arm is near either side of the tanker. The hose drum carriage 77a, a hydraulic line 86a (FIG. 1), electrical cable 87a and a take up spool 88a provide control of the operation of the hydraulic jacks 58.

Another embodiment of the present invention is disclosed in FIG. 5 wherein an elbow 94 is connected to the outboard end of the traveling loading arm for connection to a petroleum transfer hose 56a having a straight end portion with a flange 57a at the end of the hose. A pair of cables 51a (only one of which is shown) are connected between a winch 50a and the flange 57a to lift the hose into position for connection to a flange 95 on the elbow 94.

The procedure for moving the traveling loading arm from an operating position on the port side of a marine loading tanker 16 to a position on the starboard side of the tanker is shown sequentially in FIGS. 6-9. In FIG. 6 the articulated pipe assembly is shown in the extended position with the right end of the pipe assembly 10 connected to the dummy flange 68b, in position for connection to a petroleum transfer hose 56b and with the left end of the pipe assembly 10 connected to a first tanker manifold port 67a to provide fuel for one of the holds of the tanker 16. The left end of the pipe assembly can be moved to any of the desired manifold ports 67b-67d to fill the corresponding holds in the marine tanker 16. When the filling from the port side is completed the right end of the articulated pipe assembly 10 is disconnected from the dummy flange 68b, the hydraulic cylinder 39 is extended causing the articulated pipe assembly 10 to move to the collapsed position shown in FIG. 7. The T-section 28b on the right end of the pipe assembly 10 is then secured to the flange of the manifold port 67d (FIG. 7) and the T-section 28a on the left end of the pipe assembly is disconnected from the manifold port 67a. The hydraulic cylinder 39 is again collapsed so that the carriage 11a at the left end of the pipe assembly 10 moves to a position over the dummy flange 68a (FIG. 8) and the T-section 28a is clamped to the dummy flange 68a by the hydraulic coupler 66 (FIG. 5) thereby locking the articulated pipe assembly 10 in position to load the tanker from the starboard side into the manifold port 67d as shown in FIG. 8. The petroleum transfer hose 56 is connected to the left end of the pipe assembly 10 and fluid can then be transferred through the manifold port 67d into the tanker hold. The T-section 28b can be disconnected from the tanker's manifold port 67d and connected to any of the other manifold ports 67a-67c.

Thus, the present invention provides a traveling loading arm for conveniently loading a marine tanker from either side of the tanker and for connecting the loading arm between a petroleum transfer hose and any of the tanker's holds without pulling the transfer hose over the tanker's railing. The traveling loading arm can be easily stored in the position shown in FIG. 7 for draining fuel into the tanker manifold ports when the loading arm is not in use.

Although the best mode contemplated for carrying out the present invention has been herein shown and described, it will be apparent that modification and variation may be made without departing from what is regarded to be the subject matter of the invention.