Mechanical Cross-Bore Detection for Horizontal Direction Drilling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current technologies fail to effectively detect non-metallic sewer lines during Horizontal Direction Drilling (HDD) operations, leading to potential damage and leakage, as they are not equipped to handle soil conditions and depth limitations, and existing solutions are either costly or not commercially available.
Innovation Solution
A mechanical sensing device attached to an underground travel element, such as a drill head or pipe, that senses initial soil conditions and entry into pipe cavities, providing a signal to indicate cross-bore hits, utilizing spring-loaded arms or pressurized bags to detect voids like sewer pipes, and can transmit signals wirelessly or via a wire.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Difficulty of detecting and measuring
If GPR-based technologies are used to detect sewer lines, then detection capability is provided, but cost increases and limitations in certain soil conditions and depth of signal penetration occur
Solution Approach 1:
The patent replaces complex electromagnetic GPR systems with a simple mechanical sensing device that uses physical contact detection. The mechanical arms with springs provide direct tactile sensing of sewer line presence, eliminating the need for complex signal processing and addressing GPR's limitations in certain soil conditions and depths.
Solution Approach 2:
The mechanical sensing device is designed as a low-cost, simple system that can be easily manufactured and deployed. The use of basic mechanical components like springs and arms makes it economically viable compared to expensive GPR equipment, while being sufficient for the specific detection task.
2Difficulty of detecting and measuring
If acoustic technology is used to detect sewer lines, then some limitations of GPR are overcome, but the technology is relatively new and not commercially available
Solution Approach 1:
The mechanical sensing device is self-contained and does not require external support systems or specialized infrastructure. It autonomously detects sewer lines through direct mechanical contact, making it independently operable and commercially viable without relying on emerging technologies that lack commercial maturity.
3Loss of information
If CPT technology is used to characterize soil environment, then real-time data is provided, but it measures soil resistance rather than directly detecting pipe cavities
Solution Approach 1:
The mechanical arms act as intermediaries between the drilling head and the sewer line. Instead of relying on indirect soil resistance measurements, the arms directly contact and sense the presence of pipe cavities, providing more accurate detection while maintaining real-time data capability.
4Difficulty of detecting and measuring
If mechanical sensing device with spring arms is used, then detection of void spaces is achieved, but device complexity increases
Solution Approach 1:
The mechanical sensing device concentrates detection capability at specific locations (the spring arms) rather than distributing complexity throughout the entire system. The spring arms provide localized sensing at the critical interface with sewer lines, keeping the rest of the drilling system simple.
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 real-time detection of sewer line contacts, allowing operators to take corrective actions, reducing undetected incidents and integrating seamlessly with existing HDD systems at a lower cost without requiring highly trained personnel.
Implementation Method 1
The arms are in a closed position when confined in soil. When the unit encounters a void space such as inside a sewer pipe, the spring arms open and an electronic signal indicating arm movement can be recorded or sent to the surface
Implementation Method 2
Another embodiment contemplates the use of a load cell to measure force changes that indicate entry into a pipe cavity
Data Source
AI summary
A system for detecting an underground cross-bore includes a mechanical sensing device attached to an underground travel element to form a combination adapted for underground travel. The mechanical sensing device senses at least a first underground condition wherein the combination is ensconced in an underground bore and a second underground condition wherein the sensing device senses entry into a pipe cavity. The mechanical sensing device desirably can provide a signal identifying entry into a pipe cavity.