Pipe Bursting Head with Pneumatic Hammer for Fatigue Fracture
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Solution Overview
Problem
Current pipe bursting methods face challenges with high power and equipment requirements, especially when dealing with larger pipes and obstructions, leading to slow bursting rates and potential equipment failure, and often necessitate further excavation or use of larger, unwieldy machinery.
Innovation Solution
The solution combines a hydraulic cable puller with a pneumatic impactor to create a reciprocating fatigue cycle stress load on the pipe, allowing for increased bursting efficiency by varying the stress imparted to the pipe beyond what the cable alone can achieve, using the stored energy in the cable and impactor to induce cyclical fatigue failure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional pipe bursting methods are used with hydraulic cable pullers, then pipe replacement can be achieved without full excavation, but the process becomes extremely slow or stalls when encountering irregularities such as pipe connectors, valve housings, concrete overpours, or rocky soil
Solution Approach 1:
The patent applies periodic impact forces through a pneumatic hammer that delivers repeated blows to the bursting head, creating cyclic stress on the pipe. This periodic action enables the system to overcome high-resistance irregularities that would stall continuous static bursting, maintaining productivity while avoiding excavation.
Solution Approach 2:
The system transitions from static bursting to dynamic bursting by incorporating a pneumatic hammer that delivers variable impact forces. This dynamic approach allows the bursting head to adapt to varying resistance conditions encountered during pipe replacement, preventing stalling and maintaining operational efficiency.
2Force
If larger and more powerful equipment is used to handle larger pipes and obstructions, then bursting capability is improved, but the equipment becomes unwieldy and requires more space
Solution Approach 1:
The patent combines a hydraulic cable puller with a pneumatic hammer into an integrated bursting system. This merging allows the equipment to achieve high bursting capability through the synergistic effect of continuous tension and impact forces, while keeping individual component sizes manageable and the overall system portable.
Solution Approach 2:
The system changes the nature of the applied force from static to dynamic by introducing impact forces. This parameter change allows smaller equipment to achieve equivalent or superior bursting capability compared to large static systems, as the impact forces concentrate energy delivery without requiring proportionally larger equipment.
3Strength
If static bursting with continuous cable tension is used, then the pipe can be burst through consistent force, but the process is extremely slow when encountering high-resistance irregularities
Solution Approach 1:
The pneumatic hammer delivers periodic impact blows that superimpose cyclic stress on the continuous cable tension. This periodic action accelerates pipe fracture by creating fatigue effects and concentrating stress at weak points, dramatically reducing the time required to burst through high-resistance irregularities compared to static tension alone.
Solution Approach 2:
The impact forces from the pneumatic hammer create preliminary stress concentrations and micro-fractures in the pipe before the final rupture occurs. This preliminary action weakens the pipe structure in advance, allowing the cable tension to complete the bursting process more quickly and reducing overall bursting duration.
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
This approach enables pipe bursting at lower power and equipment costs, allowing for smaller, more manageable equipment to handle larger pipes and obstructions without the need for extensive excavation, by leveraging the stored energy in the cable and the impactor's stress cycles to efficiently fracture the pipe.
Implementation Method 1
the bursting head or mole is propelled by an impactor, which pushes the mole through the pipe being replaced by repetitive blows of a pneumatic hammer
Implementation Method 2
a wire cable to pull the bursting head, wherein the cable is pulled, either intermittently or continuously, with enough force to cause the bursting head to burst the pipe
Implementation Method 3
The force of the impactor, together with the released energy stored in the cable combine to produce a reciprocating fatigue cycle stress load on the pipe being replaced
Data Source
AI summary
A pipe bursting system and method are described wherein a bursting head pulled by a cable employs a relatively small pneumatic hammer and a relatively large cable tension to impose a cyclical hoop stress on the pipe being burst to cause fatigue failure of the pipe, resulting in lower size and power requirements, and higher efficiency for a given set of job requirements.