Capacitance Sensor Cross-Bore Detection in Underground Pipes
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Solution Overview
Problem
Trenchless excavation technologies, such as horizontal direction drilling, often result in unintended cross bores between underground utilities due to the inability to accurately locate and document non-metallic sewer pipes, leading to potential gas explosions and structural damage from water infiltration.
Innovation Solution
A system with a capacitance sensor-based detector mounted on a robot assembly or push rod cable, which generates an electric field to differentiate between normal embedment materials and the absence of such materials, indicating a cross bore by outputting distinct capacitance values, allowing for the detection and location of cross bores between pipes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If trenchless excavation technologies are used to install utility lines, then installation efficiency is improved and surface disruption is reduced, but the ability to locate and detect existing underground utilities is lost
Solution Approach 1:
The capacitance detector is deployed during the utility installation process itself, before final placement is confirmed, to proactively detect cross bores with existing utilities. This preliminary detection prevents problems before they become critical.
Solution Approach 2:
The patent replaces traditional mechanical visual inspection methods with an electronic capacitance-based detection system. The capacitance sensor electronically senses changes in the electromagnetic field caused by proximity to existing utilities, eliminating the need for physical sight.
2Measurement precision
If traditional visual inspection methods are used to locate utilities, then detection accuracy is improved, but installation efficiency is reduced and surface disruption increases
Solution Approach 1:
The patent replaces mechanical visual inspection methods with an electronic capacitance-based detection system. The capacitance sensor electronically senses changes in the electromagnetic field caused by proximity to existing utilities, eliminating the need for physical sight.
Solution Approach 2:
The capacitance detector serves multiple functions: it detects the presence of existing utilities, determines their approximate location, and operates within the trenchless installation process itself, combining detection and installation capabilities.
3Productivity
If utility locations are not accurately documented, then installation speed is maintained, but cross bore incidents increase causing safety hazards and structural damage
Solution Approach 1:
The capacitance detector provides real-time feedback during the installation process by continuously monitoring capacitance values and alerting operators to potential cross bores. This immediate feedback allows for course correction before damage occurs.
Solution Approach 2:
The system takes preliminary anti-action by detecting and warning of potential cross bores before they occur, preventing the harmful event rather than addressing it after the fact.
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
Enables accurate detection and location of cross bores during and after installation, preventing damage to utilities and ensuring safety by identifying abnormal pipe intersections, thus reducing the risk of gas explosions and structural deficiencies.
Implementation Method 1
The detector includes an electronic circuit module having a capacitance sensor. The detector utilizes a varying or alternating electric field, generated by the electronic circuit module, to detect the presence of absence of common embedment materials surrounding the gas pipe
Implementation Method 2
The detector utilizes a varying or alternating electric field, generated by the electronic circuit module, to detect the presence of absence of common embedment materials surrounding the gas pipe
Data Source
AI summary
An apparatus for detecting a cross-bore between a first pipe and a second pipe that are installed underground includes a support and an electronic circuit assembly. The support is movable through the first pipe. The electronic circuit assembly is mounted to the support to move through the first pipe with the support. The electronic circuit assembly includes a controller and a capacitance sensor. The capacitance sensor outputs a capacitance value based on an interaction of an electric field generated by the capacitance sensor with an environment of the first pipe. The capacitance sensor outputs to the controller a given capacitance value when the capacitance sensor is at a location where the environment of the first pipe is a cross-bore intersection with the second pipe. The controller generates an indicator indicative of a presence of a cross-bore upon the capacitance sensor outputting the given capacitance value.