Linear Valve Actuator Layout for Lightweight Deepwater Replacement
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Solution Overview
Problem
Existing linear actuators for deep ocean petroleum or natural gas conveying systems are heavy due to integrated safety elements, making them difficult to replace using a Remote Operated Vehicle (ROV).
Innovation Solution
A compact and lightweight linear actuator design that uses a hydraulic drive with an electronic control unit and electric drive unit, eliminating the need for mechanical springs and additional hydraulic components. The actuator includes a pressure fluid-filled housing for resisting external pressure, corrosion protection, and lubrication, and features a mechanical interface for coupling with a safety device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If mechanical springs and additional hydraulic components are integrated into the linear actuator for safety functions, then the safety and reliability are improved, but the weight increases making replacement difficult
Solution Approach 1:
The invention extracts the safety function from the linear actuator itself and places it in a separate safety device. The linear actuator only contains the electric drive unit and hydraulic drive, while the safety device with springs and additional safety components is coupled separately via a standard interface. This separation removes the weight penalty from the actuator while maintaining safety functionality.
Solution Approach 2:
The system is segmented into two independent functional modules: the linear actuator for normal operation and the safety device for emergency functions. This segmentation allows each component to be optimized independently - the actuator for minimal weight and the safety device for maximal safety - while working together through a standardized coupling interface.
2Device complexity
If mechanical springs are used for restoring the piston in the second direction, then the simplicity of the design is improved, but the weight and complexity increase due to additional safety elements
Solution Approach 1:
The mechanical spring restoration mechanism is extracted from the linear actuator and placed in the separate safety device. The linear actuator uses only an electric drive unit and hydraulic cylinder, eliminating the need for mechanical springs within the actuator itself, thereby reducing weight and complexity.
3Reliability
If additional hydraulic components are integrated for safety functions, then the reliability is improved, but the device complexity increases
Solution Approach 1:
Additional hydraulic components required for safety functions are extracted from the linear actuator and placed in the separate safety device. The linear actuator maintains a simple hydraulic drive with minimal components, while the safety device contains any additional hydraulic elements needed for safety operations.
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 design reduces the weight and complexity of the linear actuator, allowing for easier replacement at great depths using an ROV, while maintaining safety and reliability by automatically reducing hydraulic drive force in case of failure.
Implementation Method 1
The hydraulic drive is configured to convert an electric drive power of the electric drive unit into a hydraulic drive force for producing linear movement of the piston of the at least one hydraulic cylinder in a first direction
Implementation Method 2
The pressure fluid is preferably also used to resist external pressure acting on the linear actuator
Implementation Method 3
to protect against corrosion and to lubricate the elements of the safety device
Implementation Method 4
A linear movement of the piston of the hydraulic cylinder in a second direction opposite the first direction is generated by a restoring force on the piston rod acting on the piston rod outside the housing of the piston
Data Source
AI summary
A linear actuator for linear actuation of a process valve which has a housing is disclosed. An electronic control unit, at least one electric drive unit, and at least one hydraulic drive are located in the housing. The hydraulic drive includes at least one hydraulic cylinder with a piston and a piston rod. The piston rod extends outwardly through an opening in the housing. The hydraulic drive is configured to convert an electric drive power of the electric drive unit into a hydraulic driving force which generates a linear movement of the at least one hydraulic cylinder in a first direction. A linear movement of the piston of the hydraulic cylinder in a second direction opposite to the first direction is generated by a restoring force on the piston rod, which restoring force acts on the piston rod outside the housing.