Water-Degradable Purge Dam With Blocking Plates for High Air Flow
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Solution Overview
Problem
Conventional water degradable purge dams are not practical for high air flow environments, such as underwater pipelines, as they cannot withstand bidirectional air pressure fluctuations and may dislodge during welding, making it difficult to maintain a purge gas shield around the weld zone.
Innovation Solution
A water-degradable welding purge dam apparatus with hollow conduits and air flow blocking plates that are self-retaining and adjustable, allowing pressurized air to bypass through a sequestered zone while retaining purge gas, and made from materials that can be easily removed post-welding using hydrostatic pressure or flushing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional water degradable purge dams are used, then they can be easily removed after welding by dissolving with water, but they cannot withstand bidirectional air pressure fluctuations and may dislodge during welding
Solution Approach 1:
The purge dam is divided into multiple segments or sections that can independently withstand pressure fluctuations. The dam structure includes multiple retaining walls or barriers that work together to maintain purge gas containment while distributing the stress of bidirectional air pressure changes, preventing dislodgement while maintaining ease of water-based removal.
Solution Approach 2:
The purge dam incorporates flexible or adjustable components that can dynamically adapt to bidirectional air pressure fluctuations. The structure includes movable elements or flexible materials that allow the dam to flex and maintain seal integrity during pressure changes, while still being designed for easy removal through water degradation after welding completes.
2Reliability
If blocking members are used to prevent air flow, then they can block bidirectional air pressure surges, but they are difficult to remove following welding and may dislodge if air pressure fluctuations are large
Solution Approach 1:
The purge dam is designed as a disposable component made from water-soluble or easily degradable materials that can be discarded after serving their protective function. The dam provides reliable air pressure surge blocking during welding, then can be easily removed by flushing with water or allowing natural degradation, eliminating the removal difficulties associated with traditional blocking members.
Solution Approach 2:
The purge dam utilizes materials whose properties change in response to environmental conditions. The material maintains structural integrity and blocking capability during welding operations, then undergoes parameter changes when exposed to water or moisture, transforming from a rigid blocking structure to a degradable form that can be easily flushed away or disintegrated for simple removal.
3Manufacturing precision
If purge dams are placed in close proximity to weld zone, then they can effectively shield the weld zone from atmospheric contamination, but they cannot be used in high air flow environments
Solution Approach 1:
The purge dam employs composite material construction combining water-soluble base materials with reinforcing elements or coatings that provide enhanced mechanical strength. This composite structure enables the dam to be placed close to the weld zone for effective purge gas retention while simultaneously withstanding the bidirectional air pressure fluctuations characteristic of high air flow environments like underwater pipeline welding.
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 apparatus effectively maintains a purge gas shield in high air flow environments by withstanding bidirectional air pressure fluctuations and allows for easy removal after welding, ensuring a clean weld zone without the need for external retention methods.
Implementation Method 1
The purge dam apparatus comprises one or more water degradable materials so that the it can be flushed from the pipe assembly following welding
Data Source
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AI summary
A water-degradable welding purge dam apparatus (2) for purging a weld zone (4) of a pipe assembly (6) comprising first and second pipes (8, 10) having respective first and second ends to be welded together at a root gap(16). A first purge dam subassembly (18) is adapted for installation in the first pipe end. It has a hollow first conduit (20) defining a first air flow pathway (22) therethrough, and has one or more air flow blocking plates (24, 26, 28) fixedly mounted on the first conduit (20). A second purge dam subassembly (30) is adapted for installation in the second pipe end. It has a hollow second conduit (32) defining a second air flow pathway (34) therethrough, and has one or more air flow blocking plates (36, 38, 40) fixedly mounted on the second conduit (32). A hollow third conduit (42), defining a third air flow pathway (44) therethrough, is interconnectable to the first and second conduits (20, 32 ) members so as to span the weld zone. The first, second and third air flow pathways allow pressurized air within the pipes to pass through the purge dam apparatus and the weld zone in a sequestered by-pass zone defined by the first, second and third conduits. The purge dam apparatus comprises one or more water degradable materials so that the it can be flushed from the pipe assembly following welding.