Pre-Stressed Strand Pipe Extraction for Low-Strength Pipe Removal
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for extracting small diameter pipes are limited by the tensile strength of the pipe, which restricts the length of extraction and can result in failure during the initial pulling cycle, especially with pipes made from low-strength materials like lead, due to the high force required to break the shear bond with the surrounding soil.
Innovation Solution
A pipe extraction machine that uses a combination of a frame, carriage, actuator, wire clamp, and pipe cutter to apply a dual load path by pre-stressing a wire rope, enhancing the extraction force by maintaining tension in the wire rope throughout the extraction process, allowing for greater pipe lengths to be extracted safely.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the tensile strength of the existing pipe is used alone to extract the pipe, then the extraction method is simple, but the magnitude of extraction force is limited and the length of extraction is restricted
Solution Approach 1:
The patent combines the tensile strength of the existing pipe with the tensile strength of a wire rope strand to create a composite extraction system. The wire rope is attached to the pipe end and pulled together with the pipe, merging two force sources to achieve greater total extraction force than either component could provide alone.
Solution Approach 2:
The wire rope strand acts as an intermediary element that transfers and amplifies the extraction force. By introducing this intermediate component, the system can apply greater force to break the shear bond between the pipe and surrounding soil without directly relying on the limited tensile strength of the pipe alone.
2Length of moving object
If a wire rope strand is used to increase extraction force, then the length of pipe that can be extracted increases, but the complexity of the extraction system increases
Solution Approach 1:
The wire rope strand is integrated with the pipe extraction system by attaching it to the pipe end. This merging allows the strand to be pulled together with the pipe, extending the effective extraction length beyond what could be achieved with the pipe's own tensile strength alone.
Solution Approach 2:
The wire rope strand is pre-positioned and attached to the pipe end before the extraction process begins. This preliminary preparation allows the strand to be immediately engaged when pulling starts, enabling longer extraction distances to be achieved without requiring additional intermediate steps.
3Force
If high extraction force is applied during the initial pulling cycle, then the shear bond between pipe and soil can be broken, but pipes made from low strength materials such as lead are most likely to fail
Solution Approach 1:
The wire rope strand serves as a mediator that distributes and manages the extraction force. By having the strand attached to the pipe end and pulled together with the pipe, the force application is optimized to break the soil bond while the strand's high tensile strength prevents pipe failure, especially for low-strength materials like lead.
Solution Approach 2:
The system changes the force application parameters by introducing the wire rope strand with significantly higher tensile strength than the pipe. This parameter change allows the extraction force to be optimized - sufficient to break the shear bond but distributed in a way that prevents pipe failure, as the strand carries the majority of the load.
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 dual load path mechanism increases the extraction force, enabling the removal of longer pipes, particularly those made from low-strength materials, by distributing the load between the pipe's tensile strength and the wire rope's tensile load, reducing the risk of pipe failure during extraction.
Implementation Method 1
a strand, such as a high strength wire rope, may be passed through the inside diameter of the pipe with an obstruction, or 'pipe puller' at the far end. When the strand is pulled from the opposite end, the pipe may be removed due to the tension supplied by the strand.
Implementation Method 2
the magnitude of the force that can be applied to extract the pipe is limited exactly to the host pipe tensile strength. Each added foot of host pipe length added to the extraction length adds to the force required to break the shear bond from pipe to soil
Implementation Method 3
The actuator is connected to the frame and the carriage or moving the vise along the frame between first and second positions
Implementation Method 4
The wire clamp is supported on the carriage and has a plurality of wire jaws. The wire jaws are disposed about a central opening and configured to selectively engage a strand
Data Source
AI summary
A machine for extracting a ductile pipe. The machine has a vise which can grip the pipe, and a wire clamp. Each of the wire clamp and vise are supported on a carriage which is movable relative to a frame. This enables the vise to grip and pull the ductile pipe. Additionally, a wire strand may be disposed through the pipe from a far end to the end at which the machine is placed. The wire clamp allows the machine to pre-stress the strand to improve the extraction of the ductile pipe.