Underground Service Line Material Identification via Stress Wave Velocity

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Solution Overview

Problem

Current methods for identifying the material of underground service lines, such as visual inspections and water sampling, are time-consuming, costly, and unreliable, particularly in urban areas with scarce records of original pipe installations, leading to uncertainty about the presence of lead service lines.

Innovation Solution

A nondestructive evaluation method using a wave measurement device to generate and measure stress waves in service lines, determining the material by comparing wave velocities with known sets, facilitated by inserting a probe with an accelerometer into the ground and using a vibratory shaker to create and detect substrate waves.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If visual line inspection or water sampling methods are used to identify service line material, then the identification can be performed, but the process becomes time-consuming and costly

Engineering Contradiction:

Improveservice line material identification accuracyVSAvoididentification time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent replaces traditional mechanical/chemical identification methods (visual inspection, water sampling) with a wave-based detection system. A wave measurement device measures the velocity of waves traveling through the service line, and this velocity data is used to identify the pipe material. This substitution enables rapid, non-contact identification that is both fast and accurate, resolving the contradiction between measurement precision and time consumption.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If visual line inspection or water sampling methods are used to identify service line material, then the identification can be performed, but the cost increases significantly

Engineering Contradiction:

Improveservice line material identification accuracyVSAvoididentification cost

Core Design Contradiction:

Measurement precisionVSLoss of energy

Solution Approach 1:

The patent replaces expensive chemical analysis (water sampling) and labor-intensive visual inspection with an economical wave velocity measurement system. The wave measurement device and data acquisition system provide automated, rapid identification that reduces both direct costs and indirect labor costs while maintaining high accuracy in material identification.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If traditional inspection methods are used, then material identification is possible, but the process is unreliable particularly in urban areas with scarce records

Engineering Contradiction:

Improveidentification reliabilityVSAvoidinspection process complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces unreliable traditional methods that depend on scarce historical records with a physics-based wave velocity measurement system. The measurement system directly characterizes the pipe material through its physical properties (wave velocity) rather than relying on external documentation, thereby improving reliability. The automated data acquisition and comparison process reduces human subjectivity and increases consistency.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 method allows for rapid and cost-effective identification of service line materials, providing accurate results within approximately one hour with minimal disturbance, overcoming the limitations of existing techniques.

Implementation Method 1

generating a service line wave through an exposed portion of the service using a vibratory shaker

Methodology Applied

Scientific EffectMechanical vibration: Vibration

Implementation Method 2

identifying, by a data acquisition system, the service line wave velocity; comparing the service line wave velocity to a known set of wave velocities in service line according to a service line material

Methodology Applied

Scientific EffectStress wave propagation: Sound

Data Source

PatentUS10145820B2Identification of water pipe material based on stress wave propagation

Publication Date: 2018.12.04 DREXEL UNIV

AI summary

A nondestructive evaluation method for determining the material used in a below ground service line includes inserting a probe with a wave measurement device therein into an area corresponding to a location of a service line; inciting a service line wave through an exposed portion of the service using a vibratory shaker; measuring, by the wave measurement device, a substrate wave created by the service line wave passing thought the service line and into the substrate; identifying, by a data acquisition system, the service line wave velocity; comparing the service line wave velocity to a known set of wave velocities in service line according to a service line material; and identifying the service line material in the service line by comparing the wave velocity in the service line with the known set of wave velocities.