Winch Boom Pulley Layout for Cage-Free Pipe Bursting Retrieval
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Solution Overview
Problem
Trenchless pipe replacement technologies face challenges in minimizing the size of entry and exit pits due to limited space for operating cutting tooling, especially when replacing large quantities of HDPE gas pipes, and existing systems require extraction cages that occupy valuable space and complicate operations.
Innovation Solution
A winch boom system with pivoting pulleys and a limiter mechanism that allows the bursting tool to be pulled at an angle, eliminating the need for extraction cages and optimizing pit space, while using a polymeric pulley surface to protect the tool from damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If extraction cages are used to pull the bursting tool, then the tool can be retrieved, but the cages occupy valuable space in small entry and exit pits
Solution Approach 1:
The patent removes the extraction cage from the system entirely. Instead, the boom structure itself serves as the retrieval path, with the bursting tool being pulled directly along the boom into the pit without requiring a separate cage structure. This eliminates the space occupation problem while maintaining tool retrieval capability.
Solution Approach 2:
The boom structure serves multiple functions: it provides structural support, defines the pull angle, and acts as the retrieval path for the bursting tool. By combining these functions into a single structure, the system eliminates the need for separate extraction cages, thereby saving space in the pit.
2Productivity
If cutting tooling is operated in small entry and exit pits, then trenchless replacement can proceed, but the limited space makes cutting operations challenging
Solution Approach 1:
The patent introduces a pull angle dimension to the operation. By pulling the bursting tool at an angle along the boom rather than straight back, the system creates additional operational space and improves access for cutting tooling in the pit, making cutting operations easier while maintaining productivity.
3Adaptability or versatility
If a pulley system is used to guide the cable, then the tool can be pulled at an angle, but the pulley surface can damage the tool
Solution Approach 1:
The patent applies a polymeric material specifically to the pulley surface where contact with the bursting tool occurs. This localized material change provides a non-marring surface that allows the pulley to fulfill its guiding function while protecting the tool from damage during angled retrieval.
Solution Approach 2:
The pulley system uses a composite approach by combining the structural function of the pulley with a polymeric surface layer. This composite structure maintains the mechanical advantage and guiding capability of the pulley while the polymeric material provides protection against tool damage.
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 system reduces the size of entry and exit pits, enhances operational efficiency by freeing up space for other tasks, and prevents tool damage, facilitating seamless pipe replacement operations.
Implementation Method 1
the pulley having a polymeric bursting tool guide surface
Data Source
AI summary
A pipe replacement system and method are shown. Configurations are shown that include a pulley that does not damage a bursting tool, as the bursting tool is pulled into a pit. Configurations are also shown that include a boom that does not need an extraction cage for the bursting tool.