GB1569785A - Floating transfer station - Google Patents

Description

(54) FLOATING TRANSFER STATION (71) We, AKTIEN-GESELLSCHAFT "WESER", a joint stock Company organised under dre laws of Germany of P. O. Box 210 280, 28 Bremen 21, Germany, do hereby declare the invention, for which we pray that a patent may be granted to us, and the.

method by which it is to be performed, to be particularly described in and by the following statement: The invention relates to a floating transfer station for loading and unloading ships with a cargo capable of flowing, especially with liqui- fied gases.

Floating platforms are knawn which have an anchorage on the sea bed, which are partially submerged in the water and which have on the upper side means for mooring one or more ships. These means are constituted by bollards, slip hooks or winches for securing hawsers of the ship and in some cases for enabling warping manoeuvres to be performed.

For the transfer of the cargo-generally crude oil-by means of pipes-special constructions are necessary in order to effect the connection of the flexible connecting pipe to the ship and to a stationary pipe and to enable the ship, during cargo transfer, to perform movements in the sea including swinging through 360" about the transfer station, in the plane of the surface of the water. For this purpose, rotary joints have been used with annular chambers and specially constructed flange connections between these annular chambers and the shore pipe on the one hand and the flexible connecting pipe on the other hand.

A problem in using such a transfer station for liquified gases that are liquified by super cooling at approximately atmospheric pressure, is that owing to the extremely low temperature of the cargo, the form necessitated by these low temperatures and the material chosen, the pipes suitable for the transfer are sensitive to external mechanical actions, which arise particularly from the motion of the sea at the surface of the water. Under some conditions they are also sensitive to fluctuating external air temperatures since these may initiate thermal movements to a considerable extent.

The object of the invention is to arrange, by novel construction of the transfer station, that the pipes, flexible hoses and connecting pipes that are subject to low temperatures can as far as possible remain permanently below the surface of the water.

According to the present invention there is provided a floating transfer station for liquified gases, comprising a first anchored buoy which floats at the surface of the water, and a second anchored buoy which is connected to the first buoy by tension means and which is anchored to float below the surface of the water by means of ground anchors and anchor chains, cables or hawsers, the first buoy having means for mooring a ship, and the second buoy having means for effecting a movable connection between a pipe connected to a fixed pipe and a flexible pipe for connection to the ship.

In this way the pipes that convey the very cold cargo to be transferred are located sub stantially permanently under water, so that they are not subjected to any temperature fluctuations but on the contrary are subjected to an unvarying ambient temperature. There are no connecting floats on the surface of the water, so that damage due to sea motion, in particular waves, will not occur. Only the extreme end of the flexible connecting pipe passes through the surface of the water below the transfer point on the ship. Preferably this part of the connecting pipe is vertical as far as possible.

The second buoy may be of variable depth, the fixed pipe being a rigid shore pipe connected to the buoy by a flexible connecting pipe. The depth of this buoy is below the depth of the expected ship. The buoy having the mooring means may likewise be capable of being submerged to perrait the passage of ships over it and to facilitate warping manoeuvres of ships.

An embodiment of the invention will now be described, by way of example, with reference to the accompanying drawing, in which: The transfer station of the embodiment comprises two buoys 1 and 2. The buoy 1 has means for connecting a flexible connecting pipe 8, connected to a rigid shore pipe 3, and a flexible connecting pipe 4 for connection to a ship, which consists of rotary joints of known construction with an axis of rotation as nearly vertical as possible, and suitable flange connections.

The shore pipe 3 is, in the embodiment, embedded in the seabed, but may alternatively be anchored so as to be suspended in the water.

The shore pipe 3 may lead to a storage station arranged on the mainland or to a conveying station arranged in the open water, to a cooling device or the like for natural gas or the like.

The seaward end of the shore pipe 3 is firmly anchored in a concrete block 5 and connected by the flexible connecting pipe 8 to the buoy 1, so that the buoy can move horizontally in the water and can also vary in depth. The buoy 1 is anchored by anchor chains 9 with ground anchors 10 and if desired sinkers 11 which improve the action of the anchors 10.

The free end of the connecting pipe 4 leads to the transfer point 6 of the ship, barge or the like.

The buoy 2 has means 12 for mooring the ship 7 by means of hawsers 13 and floats at the surface of the water. It is connected by one or more cables 14 to the upper part of the buoy 1. In the embodiment the buoy 2 is submersible. A cable 15 connects the buoy 2 to a further appreciably - smaller buoy 16, which series as a marker buoy when the buoy 2 is submerged and which, when no ship' or barge is tied up to the buoy 2 for the transfer of cargo, may be secured to 'the free end of the connecting pipe 4, as is diagrammatically shown by the broken line 17.

In the above description, where chains have been referred to, hawsers or cables could be provided in their place, and where hawsers or cable have been referred to, chains could be used. As the tension means, cables, hawsers or chains are suitable.

WHAT WE CLAIM IS: 1. A floating transfer station for liquified gases, comprising a first anchored buoy which floats at the surface of the water, and a second anchored buoy which is connected to the first buoy by tension means and which is anchored to float below the surface of the water by means of ground anchors and anchor chains, cables or hawsers, the first buoy having means for mooring a ship, and the second buoy having means for effecting a movable connection between a pipe connected to a fixed pipe and a flexible pipe for connection to the ship.

2. A floating transfer station according to claim 1 in which the second buoy is variable in depth and the fixed pipe is a rigid shore pipe and the said pipe connected to the fixed pipe is a flexible connecting pipe.

3. A floating transfer station substantially as hereinbefore described with reference to the accompanying drawing.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (3)

**WARNING** start of CLMS field may overlap end of DESC **. 8, connected to a rigid shore pipe 3, and a flexible connecting pipe 4 for connection to a ship, which consists of rotary joints of known construction with an axis of rotation as nearly vertical as possible, and suitable flange connections. The shore pipe 3 is, in the embodiment, embedded in the seabed, but may alternatively be anchored so as to be suspended in the water. The shore pipe 3 may lead to a storage station arranged on the mainland or to a conveying station arranged in the open water, to a cooling device or the like for natural gas or the like. The seaward end of the shore pipe 3 is firmly anchored in a concrete block 5 and connected by the flexible connecting pipe 8 to the buoy 1, so that the buoy can move horizontally in the water and can also vary in depth. The buoy 1 is anchored by anchor chains 9 with ground anchors 10 and if desired sinkers 11 which improve the action of the anchors 10. The free end of the connecting pipe 4 leads to the transfer point 6 of the ship, barge or the like. The buoy 2 has means 12 for mooring the ship 7 by means of hawsers 13 and floats at the surface of the water. It is connected by one or more cables 14 to the upper part of the buoy 1. In the embodiment the buoy 2 is submersible. A cable 15 connects the buoy 2 to a further appreciably - smaller buoy 16, which series as a marker buoy when the buoy 2 is submerged and which, when no ship' or barge is tied up to the buoy 2 for the transfer of cargo, may be secured to 'the free end of the connecting pipe 4, as is diagrammatically shown by the broken line 17. In the above description, where chains have been referred to, hawsers or cables could be provided in their place, and where hawsers or cable have been referred to, chains could be used. As the tension means, cables, hawsers or chains are suitable. WHAT WE CLAIM IS:

1. A floating transfer station for liquified gases, comprising a first anchored buoy which floats at the surface of the water, and a second anchored buoy which is connected to the first buoy by tension means and which is anchored to float below the surface of the water by means of ground anchors and anchor chains, cables or hawsers, the first buoy having means for mooring a ship, and the second buoy having means for effecting a movable connection between a pipe connected to a fixed pipe and a flexible pipe for connection to the ship.

2. A floating transfer station according to claim 1 in which the second buoy is variable in depth and the fixed pipe is a rigid shore pipe and the said pipe connected to the fixed pipe is a flexible connecting pipe.

3. A floating transfer station substantially as hereinbefore described with reference to the accompanying drawing.