Loading assembly for conveying a pressurized gas stream and a switching system for use in a loading assembly

Patent metadata

Field	Value
Publication number	US-10919756-B2
Application number	US-201415029207-A
Country	US
Kind code	B2
Filing date	Oct 17, 2014
Priority date	Oct 18, 2013
Publication date	Feb 16, 2021
Grant date	Feb 16, 2021

Abstract

A loading assembly has a gas conduit that extends between a floating structure and another structure, to convey a pressurized gas stream between the two structures. An emergency disconnection coupler is configured in the gas conduit. A switching system is provided for controlling switching of an engagement mechanism in the emergency disconnection coupler between a locked position and an unlocked position (in either direction). The switching system is subject to two distinct fail-safe regimes: a fail-unlocked regime which inherently instructs for release of the emergency disconnection coupler, and a fail-closed regime which inherently precludes release of the emergency disconnection coupler when there is pressurized gas in the gas connection. The fail-unlocked regime is active when the gas pressure in the gas connection is below a predetermined override threshold value. The fail-locked regime overrides the fail-unlocked regime.

First claim

The invention claimed is:

1. A loading assembly for conveying a pressurized gas stream between a floating structure and another structure that is located adjacent to the floating structure, the loading assembly comprising:
a gas conduit adapted to extend between the floating structure and the other structure, to convey a pressurized gas stream between the two structures;
an emergency disconnection coupler configured in the gas conduit for establishing a selectively connectable and disconnectable gas connection between the floating structure and the other structure through the gas conduit, and wherein the emergency disconnection coupler comprises an actuating coupling that is selectively switchable between a locked position and an unlocked position, whereby in said locked position the gas connection is established and whereby in said unlocked position the gas connection is interrupted whereby the actuating coupling physically disengages when the actuating coupling is in the unlocked position;
a switching system configured to control the switching of the actuating coupling in the emergency disconnection coupler between the locked position and the unlocked position, wherein the switching system is adapted to be responsive to two distinct fail-safe regimes contingent upon an internal gas pressure in the gas connection:
a fail-unlocked regime when the internal gas pressure in the gas connection is below a preselected override threshold value, which sets the switching system to unlock the actuating coupling upon power loss, and
a fail-locked regime which sets the switching system to lock the actuating coupling when the internal gas pressure in the gas connection is at or above the preselected override threshold value,
the switching system comprising:
a selection switch functionally coupled to the actuating coupling to control switching of the actuating coupling between said locked position and unlocked position at least when the switching system is in said fail-unlocked regime; and
an override switch having an override position that is activated by the internal gas pressure, and a release position, wherein the override switch is forced in the override position when the internal gas pressure is at or above the preselected override threshold value, in which case the pressure gate overrides the selection switch whereby, regardless of whether the selection switch is in open state or in closed state, the actuating coupling is instructed to assume the locked position, and wherein movement of the actuating coupling from said locked position to said unlocked position can only proceed when said internal gas pressure is below said preselected override threshold value and the override switch is not activated, wherein the override switch is part of a pressure gate that is driven by the internal gas pressure within the gas connection.

2. The loading assembly of claim 1 , wherein the selection switch has an open state and a closed state whereby upon selecting the open state the actuating coupling is instructed to assume the unlocked position and whereby upon selecting the closed state the actuating coupling is instructed to assume the locked position, wherein the selection switch is a fail-open switch.

3. The loading assembly of claim 1 , wherein the override switch is in fluid communication with the gas connection via a gate line, whereby the override switch is physically forced into the override position by the internal gas pressure in the gas connection, and into the release position by a bias force directed against said internal gas pressure.

4. The loading assembly of claim 1 , wherein the actuating coupling comprises a hydraulically powered actuator powered by a hydraulic fluid that is circulated through a hydraulic circuit by a hydraulic power unit from a pressure source to a tank,
wherein the hydraulically powered actuator comprises a first hydraulic communication port through which the hydraulic fluid can pass and a second hydraulic communication port through which the hydraulic fluid can pass,
wherein a positive pressure differential between the first hydraulic communication port and the second hydraulic communication port causes a driving force on the actuating coupling directed from the unlocked position towards the locked position, and wherein a negative pressure differential between the first hydraulic communication port and the second hydraulic communication port causes an opposite driving force on the actuating coupling directed from the locked position to the unlocked position.

5. The loading assembly of claim 4 , wherein the pressure source comprises a pump and an accumulator, wherein the accumulator is sized to hold a sufficient amount of hydraulic fluid under sufficient pressure to force the actuating coupling from the unlocked into the locked position when the hydraulic fluid is released from the accumulator.

6. The loading assembly of claim 4 , wherein the selection switch comprises a first directional control valve configured in the hydraulic circuit between the first hydraulic communication port and the second hydraulic communication port on one side and the hydraulic power unit on another side, wherein the first directional control valve comprises at least two positions, whereby one of the at least two positions corresponds to the open state and another one of the at least two positions corresponds to the closed state, wherein the first directional control valve is moved into its closed state upon applying actuation power, wherein the first directional control valve is biased to move towards the open state upon loss of actuation power.

7. The loading assembly of claim 6 , wherein the override switch comprises a second directional control valve and a third directional control valve, which second directional control valve and third directional control valve are simultaneously movable, wherein the override switch is biased in a direction against the internal gas pressure.

8. The loading assembly of claim 7 , wherein the override switch comprises a pneumatic actuator that transfers the internal gas pressure into movement of the override switch in an override position when the internal gas pressure is at or above the preselected override threshold value, and wherein the bias imposes movement of the override switch out of the override position.

9. The loading assembly of claim 6 , wherein the loading assembly comprises a backup hydraulic circuit, a backup hydraulic power unit in addition to the hydraulic circuit and the hydraulic power unit, and
wherein the selection switch comprises a backup first directional control valve, and
wherein the override switch comprises a backup second directional control valve and a backup third directional control valve, all in addition to the first directional control valve, the second directional control valve and the third directional control valve, and
wherein the backup hydraulic circuit, the backup first directional control valve, the backup second directional control valve and the backup third directional control valve are configured relative to the backup hydraulic power unit and the actuating coupling, in functionally the same way as the hydraulic circuit, the first directional control valve, the second directional control valve and the third directional control valve are configured relatively to the hydraulic power unit and the actuating coupling, and
wherein the first directional control valve and the first backup directional control valve are mechanically coupled and actuated with the same actuation power as the first directional control valve,
whereby the first directional control valve and the first backup directional control valve are forced to assume mutually the same positions, and
wherein

Assignees

• Shell Oil Co

Inventors

• Vega Perez Pablo Antonio
• Latil Serge

Classifications

• B67D9/00 Primary

  Apparatus or devices for transferring liquids when loading or unloading ships (ship-based equipment B63B27/00) · CPC title

• F17C5/06

  for filling with compressed gases · CPC title

• F16L25/00

  Construction or details of pipe joints not provided for in, or of interest apart from, groups F16L13/00 - F16L23/00 (adjustable or allowing movement F16L27/00; with fluid cut-off means F16L29/00; quick-acting F16L37/00; for double-walled or multi-channel pipes F16L39/00; connecting arrangements or other fittings specially adapted to be made of plastics or to be used with pipes made of plastics F16L47/00; specially adapted for pipes of brittle material F16L49/00) · CPC title

• F17C13/082

  for large sea-borne storage vessels (load-accommodating arrangements for ships or waterborne vessels B63B25/12) · CPC title

• F17C2250/07

  Actions triggered by measured parameters · CPC title