Pusher Box for Confined Space Pipe Liner Insertion
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Solution Overview
Problem
Existing trenchless pipe refurbishment technologies face challenges in inserting a full-length liner pipe into host pipes located in confined spaces, such as under roads with steep inclines and nearby waterways, due to physical space limitations and access constraints.
Innovation Solution
The use of a confined space insertion tool, known as a pusher box, which allows for the insertion of the liner pipe in concatenated sections, utilizing rods and wireframe centering balls to stabilize and guide the liner pipe into the host pipe, enabling expansion and grouting without the need for full-length access.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a full-length liner pipe is inserted into the host pipe from one end, then the liner pipe can be installed in a single continuous piece, but the physical space limitations and access constraints in confined spaces prevent this insertion method from being feasible
Solution Approach 1:
The liner pipe is divided into multiple sections that can be inserted separately into the host pipe. Each section is pushed through using rods that are fed from the confined access point, allowing the liner to be installed in segments rather than as a single continuous piece, thus overcoming the access limitations.
Solution Approach 2:
The liner pipe sections are inserted inside the host pipe through a nested configuration where the liner is pushed through the existing host pipe structure using rods that pass through the liner sections. This nesting approach allows installation from a confined access point without requiring external space.
2Manufacturing precision
If the host pipe is expanded to accommodate the liner pipe, then the liner pipe can be installed with proper fit and grouting, but the expansion process requires significant space and access for equipment deployment
Solution Approach 1:
The expansion process is divided into multiple stages corresponding to each liner pipe section insertion. The host pipe is expanded incrementally as each liner section is pushed through, allowing the expansion equipment to remain compact and operate from the confined access point without requiring large workspace.
Solution Approach 2:
The expansion force is applied radially inward from the host pipe wall toward the center, utilizing the circular cross-sectional geometry of the pipe. This dimensional approach allows expansion to occur within the existing pipe structure without requiring external space, as the force is generated and applied from within the pipe's internal diameter.
3Ease of operation
If rods are used to push liner pipe sections through the host pipe, then the liner can be installed in confined spaces, but the rods require concatenation and management which increases operational complexity
Solution Approach 1:
Multiple rod segments are concatenated end-to-end to form a continuous pushing mechanism. The rods are combined into a single unified tool that can be fed through the liner sections and used to push the entire liner assembly through the host pipe, reducing the number of separate operations required.
Solution Approach 2:
The rod concatenation process is designed to maintain continuous pushing force on the liner pipe sections throughout the insertion process. The rods are connected and managed in a way that ensures uninterrupted force transmission from the confined access point through the entire length of the liner assembly, eliminating the need to stop and reset the pushing mechanism.
Data Source
AI summary
Methods are disclosed for refurbishing an existing host pipe. According to presently preferred embodiments, a first phase is to make a longitudinal cut in the host pipe. A second phase is an expansion phase, wherein the host pipe is expanded, preferably nondestructively, via separation of the longitudinal cut. A third phase is to insert liner pipe sections into the expanded host pipe. In confined space environments, sections of liner pipe are concatenated end-to-end as they are inserted into the host pipe. In some embodiments, the expansion phase and the liner pipe section insertion phase may be combined. A fourth phase is to grout the annular space formed between the host pipe and the concatenated liner pipe sections.