Subsea Filter Hot-Stab Design for Maintenance
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Solution Overview
Problem
Existing subsea filters used in hydraulic actuators are prone to blockage due to sand, sediment, and marine growth, leading to inefficiency and inoperability of subsea equipment, requiring the entire subsea structure to be recovered to the surface for filter replacement.
Innovation Solution
A subsea filter design featuring an elongate connecting plug with fluid flow paths and at least one filtration screen located outside the flow ports, allowing for easy replacement by a diver or ROV without requiring significant subsea asset recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a traditional subsea filter is used, then the filter provides basic filtration, but the filter is prone to blockage and requires recovery of the entire subsea structure for replacement
Solution Approach 1:
The filter is segmented into a modular design where the filtration screen is a separate replaceable component from the connecting plug and receptacle. This allows the filter screen to be replaced independently without recovering the entire subsea structure, resolving the contradiction between ease of operation and device complexity.
Solution Approach 2:
The filtration screen is extracted as a separate removable component that can be independently accessed and replaced. The screen can be removed from the connecting plug and replaced without affecting the rest of the subsea structure, enabling easy maintenance while keeping the overall system complexity manageable.
2Reliability
If the filter is positioned to filter seawater effectively, then filtration is provided, but the filter becomes blocked by sand, sediment, and marine growth
Solution Approach 1:
The filter screen is designed with a self-cleaning feature where hydraulic fluid flow through the connecting plug creates a cleaning effect on the screen surface. This preliminary cleaning action prevents excessive accumulation of debris that would lead to blockage, thereby extending the filter's service life while maintaining effective filtration.
Solution Approach 2:
The filter system performs self-maintenance through the hydraulic fluid flow that automatically cleans the filtration screen during normal operation. This self-service mechanism reduces the frequency of manual interventions and extends the service life between maintenance operations while preserving filtration effectiveness.
3Ease of manufacture
If the filter screen is located inside the flow path, then filtration is provided, but the filter requires complex recovery operations for maintenance
Solution Approach 1:
The filtration screen is extracted from the internal flow path and positioned as an external component that can be accessed from the seawater side. This allows the screen to be removed and replaced without complex recovery operations, significantly reducing maintenance time while maintaining effective filtration.
Solution Approach 2:
Instead of positioning the filter screen inside the flow path requiring internal access for maintenance, the screen is positioned outside the flow path accessible from the seawater side. This inverted arrangement allows simple external replacement operations rather than complex internal recovery operations, reducing maintenance time while preserving filtration function.
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 filter effectively prevents blockage by allowing for easy maintenance and replacement, maintaining the operational efficiency of subsea equipment without the need for extensive surface recovery operations.
Implementation Method 1
at least one filtration screen; the filtration screen being located outside the second flow port in order to filter seawater entering the fluid flow path by the second flow port
Data Source
AI summary
A replaceable subsea filter uses a hot-stab style connection. The filter has a flow path located along a central axis. At a distal end of the of the filter, the flow path locates inside a subsea receptable, typically associated with a reservoir or sea chest for a hydraulic actuator. At a proximal end, the flow path opens into an annulus around the stab-connecter, the annulus being separated from the surrounding waters by annular filters.