Longitudinal Wave Inspection for HDPE Pipe Joints
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Solution Overview
Problem
Current inspection techniques for high density polyethylene (HDPE) pipe joints, such as phased array ultrasonic inspection, face difficulties due to the material's acoustic properties, particularly when the fusion line is perpendicular to the material surface, making it challenging to detect flaws like lack of fusion, cold fusion, inclusions, and voids in a non-destructive manner.
Innovation Solution
A pipe inspection tool that includes two search units, a pipe scanner, a pulser-receiver module, and a phased array testing instrument, calibrated using a HDPE calibration tool with bores of varying depths, propagates longitudinal sound waves at different angles to detect flaws in HDPE pipe joints, overcoming the limitations of shear wave propagation in HDPE material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If phased array ultrasonic inspection is used to inspect HDPE pipe joints, then non-destructive testing capability is provided, but the inspection effectiveness deteriorates due to HDPE material's acoustic properties hindering shear sound wave propagation
Solution Approach 1:
The patent changes the acoustic wave parameter from shear waves to longitudinal waves. The transducer is configured to generate longitudinal acoustic waves instead of shear waves, which overcome the material's resistance to shear wave propagation. This parameter change allows effective inspection of HDPE pipe joints despite the material's unfavorable acoustic properties for traditional ultrasonic inspection methods.
2Manufacturing precision
If the fusion line is perpendicular to the material surface as in HDPE butt joints, then proper fusion joint geometry is achieved, but inspection difficulty increases because shear sound waves cannot propagate effectively through the material
Solution Approach 1:
The patent changes the wave propagation mode from shear to longitudinal. By orienting the transducer to generate longitudinal waves that travel parallel to the fusion line rather than perpendicular to it, the inspection method overcomes the geometric constraint of perpendicular fusion lines. The longitudinal waves can propagate through the HDPE material effectively regardless of the fusion line orientation.
3Ease of manufacture
If traditional ultrasonic inspection methods are used, then existing inspection protocols are maintained, but the ability to detect flaws such as lack of fusion, cold fusion, inclusions, and voids deteriorates
Solution Approach 1:
The patent changes the fundamental inspection parameter from shear wave ultrasonic inspection to longitudinal wave ultrasonic inspection. This enables detection of flaws like lack of fusion, cold fusion, inclusions, and voids that are invisible to traditional shear wave methods. The system maintains ease of manufacture by using standard ultrasonic equipment while changing the operational parameters to match HDPE material properties.
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
The solution enables effective non-destructive inspection of HDPE pipe joints by accurately detecting flaws, ensuring the integrity of fused HDPE pipe joints, thereby reducing the risk of costly repairs and improving maintenance efficiency.
Implementation Method 1
utilizing a longitudinal acoustic wave to identify at least one void formed in the block
Implementation Method 2
phased array ultrasonic inspection is a technique which involves directing acoustical energy towards an object to determine whether the object contains flaws
Data Source
AI summary
A system and method directed to inspecting a high density polyethylene pipe. The system includes a pipe inspection tool that is positioned about a fused polyethylene pipe joint. The inspection tool may include search units, a pipe carriage, a pulser and a phased array testing instrument programmed to adjust an amplitude response signal from the search units based on a vertically established time corrected gain curve. The inspection tool is rotated around the high density polyethylene pipe joint while propagating acoustical waves at various patterns and angles through the polyethylene pipe joint. Prior to the joint inspection, the inspection tool is calibrated using a calibration tool which includes a block having an array of equal sized bores positioned along different axis' through the block's depth. The block is constructed of the same material type and grade as the pipes that were fused together to form-the polyethylene pipe joint.