Depth-Compensated Actuator With Nested Rods for Subsea Heave Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing depth compensated actuators for subsea use are bulky, heavy, and have high friction, requiring large space and weight, and lack a free pressure surface for active piston rod control.
Innovation Solution
A system comprising a depth compensated actuator and a gas accumulator, utilizing a hollow rod actuator and a high-pressure depth compensator cylinder to reduce size, weight, and friction, while adding an extra pressure surface for active control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If prior art depth compensated actuators are used, then depth compensation function is achieved, but the device size and weight increase significantly
Solution Approach 1:
The patent merges the depth compensator and actuator into a single integrated unit. The depth compensator piston rod is directly connected to the actuator piston, eliminating the need for separate compensator and actuator components. This integration reduces overall device weight while maintaining the depth compensation function through the combined hydraulic system.
Solution Approach 2:
The patent implements a nested configuration where the actuator piston rod is positioned inside the depth compensator piston rod, creating a telescopic structure. The actuator cylinder is nested within the depth compensator cylinder, with the actuator piston operating within the annular space between the compensator piston and compensator piston rod. This nesting arrangement significantly reduces the overall device size and weight.
2Reliability
If prior art depth compensated actuators are used, then depth compensation function is achieved, but the device occupies larger space
Solution Approach 1:
The nested configuration of cylinders and pistons reduces the radial dimension of the device. The actuator cylinder fits within the depth compensator cylinder, and the pistons are arranged concentrically, minimizing the overall cross-sectional area and footprint of the device while maintaining full functionality.
Solution Approach 2:
The patent transitions from a side-by-side arrangement of compensator and actuator to a concentric, multi-dimensional configuration. By utilizing radial and axial dimensions efficiently through nested cylinders and pistons, the device achieves compactness in all spatial dimensions, significantly reducing the required installation space.
3Reliability
If prior art depth compensated actuators are used, then depth compensation function is achieved, but friction increases
Solution Approach 1:
The patent extracts the friction-generating interface between separate compensator and actuator components by integrating them into a single unit. The direct connection between the depth compensator piston rod and actuator piston eliminates intermediate connection points and reduces the number of sealing interfaces, thereby reducing overall friction in the system.
4Reliability
If prior art depth compensated actuators are used, then passive depth compensation is achieved, but active piston rod control capability is lost
Solution Approach 1:
The integrated design creates a multi-functional system that can operate in both passive and active modes. The free pressure surface on the actuator piston rod, created by the integration, serves dual purposes: it enables passive depth compensation through pressure equalization and simultaneously provides an interface for active control through hydraulic or pneumatic pressure application. This universal design allows the same structure to perform multiple functions.
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
The system achieves significant reduction in size, weight, and friction, enabling more efficient and effective subsea operations with improved active control capabilities.
Implementation Method 1
a gas accumulator (38) with a first (39) and second (40) piston, the second piston (40) configured to reciprocate inside the first piston cylinder (42)
Implementation Method 2
When exposed to increasing water pressure due to increasing water depths, the external water pressure will act on the free surface of the exposed piston rod of the third cylinder, forcing the piston upwards
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The publication relates to a depth compensated actuator (0), for a transportable inline depth compensated heave compensator for subsea lifting operations. The actuator (1,10) comprises a cylinder shaped body (1 1 ) and a piston (12) with a piston rod (3, 13), the piston rod being intended for exposure to external water pressure, a first and second connection means (14) associated with the actuator. Further, the actuator comprises a depth compensator (20) comprising a cylinder, a piston and a piston rod, the end of which being exposed to surrounding water; and conduit means (17) between at least one volume in the actuator and one volume in the depth compensator. The pistons and piston rods are shaped as any of: hollow piston rod, ring shaped piston, ring piston rod. The depth compensated actuator solves the problem if improving depth compensation performance regarding size, weight, required fluid consumption, internal/inherent friction and adaptability. Further, use of a depth compensated actuator is claimed.