Lead Pipe Expansion With Beaded Wire Rope for Extraction
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Solution Overview
Problem
Ductile lead pipes used for water supply connections often have collapsed sections due to low yield strength and scale buildup, restricting the passage of wire ropes for extraction, leading to insufficient axial force for removal and potential tensile failure of small wire ropes.
Innovation Solution
A method involving a wire rope with progressively larger beads is used to expand the effective diameter of collapsed pipe sections, allowing a larger wire rope to be inserted for extraction, reducing tensile stress and enabling successful removal of lead pipes from the soil.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a small wire rope is used to pass through collapsed pipe sections, then the wire rope can be inserted, but insufficient axial force is available for extraction and tensile failure occurs
Solution Approach 1:
The patent applies nesting by placing a first smaller wire rope through the collapsed section to expand it, then inserting a second larger wire rope through the same section. The smaller wire rope serves as a temporary tool that enables the larger wire rope to pass through, similar to nested dolls where a smaller object fits within a larger one. This resolves the contradiction by using the small wire rope not for extraction, but solely for preparing the passage for the larger wire rope that will provide sufficient extraction force.
Solution Approach 2:
The patent applies preliminary action by expanding the collapsed pipe section before attempting to insert the larger extraction wire rope. The first wire rope with beads is pulled through to reshape and expand the collapsed section in advance, creating a passage large enough for the second wire rope. This preliminary preparation eliminates the risk of tensile failure during extraction, as the larger wire rope is inserted only after the passage is adequately prepared.
2Force
If the pipe collapsed section effective diameter is small, then the pipe maintains its original structure, but wire rope passage is restricted
Solution Approach 1:
The patent applies segmentation by dividing the wire rope insertion process into two distinct stages: first inserting a small wire rope to expand the collapsed section, then inserting a larger wire rope for extraction. The collapsed section itself is effectively segmented into a preparation phase (with small wire rope) and an extraction phase (with large wire rope). This segmentation allows each wire rope to be optimized for its specific function without compromise.
Solution Approach 2:
The first small wire rope acts as an intermediary tool that mediates between the collapsed pipe section and the second larger wire rope. It temporarily modifies the pipe section to create a passage suitable for the larger wire rope, then is removed. This intermediary approach allows the system to achieve both goals: maintaining the pipe's original structure where possible while creating the necessary passage for high-force extraction.
3Length of moving object
If beads are pulled through collapsed section to upsize diameter, then larger wire rope can be inserted, but device complexity increases
Solution Approach 1:
The patent applies parameter changes by modifying the physical state of the collapsed pipe section through the mechanical action of beads pulled through it. The beads cause localized plastic deformation that permanently changes the diameter parameter of the collapsed section from its restricted state to an expanded state. This parameter change is achieved through a relatively simple mechanism—pulling beads on a wire rope through the section—avoiding the need for complex expansion devices.
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 method effectively expands pipe diameters to accommodate larger wire ropes, reducing extraction forces and preventing wire rope failure, allowing for successful removal and potential lining or replacement of ductile pipes with minimal excavation.
Implementation Method 1
pulling the wire rope through the collapsed section of pipe such that the at least one bead passes through the collapsed section to upsize the effective diameter of the collapsed section
Data Source
AI summary
A method for enlarging a crushed section of a ductile pipe. A wire rope having a bead or plurality of beads attached to the rope is placed in a ductile pipe. When a series of beads is used, each of the beads is sequentially larger. The wire rope is pulled through the crushed section, and the ductile pipe conforms to the larger diameter of the beads. The crushed section of pipe may be expanded so that a larger wire rope suitable for pipe extraction may be passed through. Alternatively, the pipe may be reformed and expanded to near or greater than its original size. The pipe may then be coated or a smaller slip-lined pipe may be placed within the original pipe.