Hydraulic Isolation Cylinder for Leak-Resistant Position Control
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Solution Overview
Problem
Hydraulic actuators face issues with internal leakage in rotary motors leading to inaccurate position detection, fluid contamination, and the need for costly conversions between fail-in-place and fail-safe actuators, especially in subsea applications.
Innovation Solution
The Hydraulic Isolation Cylinder (HIC) system limits fluid volume flow, approximates position detection without external sensors, isolates fluid types, and allows conversion to fail-safe actuators without mechanical changes, using a fixed or adjustable volume to match pressure requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydraulic actuators are used in rotary motors, then actuation force is provided, but internal leakage occurs leading to inaccurate position detection
Solution Approach 1:
The hydraulic system is segmented into two separate circuits: a control circuit containing the HIC and a driven circuit containing the rotary motor. This segmentation isolates the control function from the driven function, preventing internal leakage in the motor from affecting position detection accuracy in the HIC.
Solution Approach 2:
The HIC acts as an intermediary device between the hydraulic power source and the rotary motor. It provides position control by limiting fluid volume flow to the motor, while its isolated control circuit prevents leakage from the motor from contaminating the control circuit and compromising position detection.
2Reliability
If conventional hydraulic actuators are used, then fluid power is transmitted, but fluid contamination occurs
Solution Approach 1:
The hydraulic system is divided into separate control and driven circuits, each with their own fluid pathways. This physical segmentation prevents contamination from the driven circuit (rotary motor) from entering the control circuit (HIC), maintaining fluid cleanliness in the control system.
3Reliability
If actuator type conversions are performed, then fail-safe operation is achieved, but costly mechanical changes are required
Solution Approach 1:
The HIC serves as an intermediary control device that enables fail-safe operation through hydraulic control rather than mechanical redesign. By controlling fluid volume flow to the motor, the HIC can prevent the motor from reaching positions that would cause failure, achieving fail-safe operation without costly mechanical modifications to the actuator itself.
Solution Approach 2:
The invention replaces mechanical conversion approaches with a hydraulic control approach. Instead of mechanically modifying the actuator to achieve fail-safe operation, the HIC uses hydraulic pressure and volume control to prevent unsafe positions, reducing conversion costs and complexity.
4Measurement precision
If fluid volume flow is limited by HIC, then position control accuracy is enhanced, but system complexity increases
Solution Approach 1:
The HIC performs multiple functions within a single device: it limits fluid volume flow to control motor position, detects piston position through hydraulic pressure, and provides fail-safe control. This multi-functionality reduces the need for separate components, thereby minimizing the increase in system complexity while achieving precise position control.
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 HIC system enhances position control accuracy, prevents fluid contamination, and facilitates cost-effective conversions between actuator types, ensuring reliable operation and reduced maintenance in challenging environments.
Implementation Method 1
a hydraulic actuator typically uses the pressure of a liquid (usually oil) to cause a piston to slide inside a hollow cylindrical tube
Implementation Method 2
An HIC includes a cylinder, an internal piston that can slide within the cylinder, and a maximum travel distance for the piston that limits a volume of the hydraulic fluid that can travel through the HIC
Data Source
AI summary
An embodiment includes a device that limits the fluid volume that can travel through a hydraulic system or loop before stopping the flow of hydraulic fluid. This can be used to limit the number of rotations/overall movement of a hydraulic motor. It can also be used to create an intermediate position of a hydraulic cylinder between fully extended or retracted. An embodiment enables the direct replacement of a direct acting, piston type actuator with that of a rotary vane motor without reworking the control devices or procedure/training of users/operators. An embodiment can be used to approximate the binary position of a remote actuator without directly monitoring that actuator.