Lead Pipe Spudding for Collapsed Section Expansion and 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 pipe removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
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 pipe removal and tensile failure occurs
Solution Approach 1:
The bead is pulled through the collapsed pipe section before the wire rope is used for pipe extraction. This preliminary action expands the collapsed section to create sufficient clearance for the wire rope to pass through, eliminating the need to use a small wire rope that would limit extraction force.
Solution Approach 2:
The solution separates the expansion function from the extraction function. The bead performs the expansion task, while the wire rope performs the extraction task. This segmentation allows each component to be optimized for its specific function without compromise.
2Shape
If the pipe collapsed section effective diameter is small, then the pipe maintains its original dimensions, but wire rope passage is restricted
Solution Approach 1:
The bead is pulled through the collapsed section in advance to expand it. This preliminary expansion creates the necessary clearance for wire rope passage while the pipe remains in its original position and largely maintains its original dimensions outside the collapsed section.
Solution Approach 2:
The bead acts as an intermediary tool that temporarily alters the pipe's collapsed section to enable wire rope passage. The bead passes through, expands the section, and is then removed, leaving the pipe in an expanded state without requiring permanent modification of the pipe's overall shape.
3Adaptability or versatility
If ductile pipe is used for water supply connections, then the pipe can be formed with bends, but the pipe has low yield strength and collapses during installation
Solution Approach 1:
The low yield strength of ductile pipe that causes collapse during installation is converted into a benefit. The collapsed section, which would normally be a defect, becomes an expandable feature that can be remediated by pulling the bead through, ultimately improving the pipe's functionality rather than rendering it useless.
Solution Approach 2:
The physical state of the collapsed pipe section is changed by applying radial expansion force through the bead. This changes the geometric parameters of the collapsed section, transforming it from a restricted state to an expanded state with sufficient clearance for wire rope passage.
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.