Hinged Arm Fluid Transfer Rotary Seal Relocation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing fluid transfer systems between fixed or floating installations and shuttle LNG carriers face issues with unbalanced outer arms, heavy rotary joints being transferred to the ship, and the risk of the emergency disconnection device causing the ship to tip over during emergency disconnections due to vertical orientation.
Innovation Solution
The system incorporates a counterweight mechanism mounted on the support structure side of the inner arm, connected to the outer arm via connecting means, and features a horizontal emergency disconnection mechanism with three perpendicular rotary joints to prevent tilting, along with a deformable parallelogram for balancing and minimizing mass and size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a heavy rotary joint is arranged at the articulation to the outer arm, then the connection/disconnection device can rotate, but a relatively large weight is placed at the free end of the inner arm
Solution Approach 1:
The rotary joint is extracted from the free end of the inner arm and relocated to the support structure. This extraction removes the heavy rotating mechanism from the problematic location, eliminating the large weight concentration at the free end while preserving the necessary rotation capability through the alternative mounting position.
Solution Approach 2:
The inner arm serves as an intermediary element between the support structure and the outer arm. By mounting the rotary joint on the support structure rather than at the outer arm articulation, the inner arm mediates the mechanical connection while avoiding direct placement of heavy rotating components at its free end.
2Device complexity
If the outer arm is not balanced, then the structure is simpler, but the system experiences instability and increased forces on the ship
Solution Approach 1:
A counterweight is introduced on the support structure to balance the outer arm. This counterweight creates an opposing moment that compensates for the unbalanced mass distribution, stabilizing the system and reducing dynamic forces transmitted to the ship during operation.
3Device complexity
If the emergency disconnection device is vertical, then the disconnection mechanism is simple, but the abandoned part can tip over during emergency disconnection
Solution Approach 1:
The emergency disconnection mechanism is reoriented from a vertical configuration to a horizontal configuration. This dimensional change in orientation eliminates the tipping hazard by aligning the mechanism parallel to the ship's deck, preventing gravitational instability during emergency disconnection operations.
4Weight of stationary object
If heavy parts are transferred to the shuttle LNG carrier or mounted on the manifold, then the support structure is lighter, but the ship experiences increased load and potential damage
Solution Approach 1:
Counterweights are positioned on the support structure to balance the articulated arms, reducing the net dynamic forces transmitted to the ship's manifold. This balancing approach minimizes the load variations experienced by the ship during arm movement and operation.
Solution Approach 2:
The support structure is designed to maintain a relatively constant potential position through proper counterbalancing, reducing the transmission of dynamic forces and energy variations to the ship's manifold during normal operation and emergency scenarios.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution balances the outer and inner arms, reduces forces on the ship's manifold, minimizes mass mobilization, enhances structural stiffness, and prevents the ship from tipping over during emergency disconnections by aligning the emergency disconnect mechanism with the manifold.
Implementation Method 1
a counterweight which is mounted on the support structure-side end of the inner arm, so as to rotate with this arm when the latter rotates around its longitudinal axis, and is connected to the outer arm by connecting means
Implementation Method 2
the counterweight is arranged at an angle to a mechanism for connecting the inner and outer arms, in the form of a deformable parallelogram and rotationally fixed to the inner arm
Implementation Method 3
the device for connecting/disconnecting to/from a ship manifold comprises three rotary joints whose rotary axes are perpendicular to each other, an emergency disconnection mechanism and means for removable connection to the manifold
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The invention concerns a system for transferring fluid between a fixed or floating facility for producing or storing fluid and a vessel such as a liquid natural gas carrier. The system comprises at least one hinged arm arrangement (2) that comprises an inner arm (10) hinged at one end to a support structure (6), so as to pivot in a vertical plane, and an outer arm (12) hinged on the outer end of the inner arm (10), the hinged arm arrangement (2) further comprising a rotary seal (18) of which the axis extends in the longitudinal direction of this arm. The invention is characterised in that the rotary seal (18) is disposed at the hinge (8) linking the inner arm (10) to the support structure (6). The invention can be used for transferring fluid from a storage facility to a carrier vessel.