Dynamic-Focus THz Measurement for Corrugated Pipe Layers

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Solution Overview

Problem

Measuring corrugated pipes with non-contact THz methods is complex due to their unique structural features, such as corrugations and varying distances from the pipe axis, leading to challenges in accurately determining distances, layer thicknesses, and surface properties.

Innovation Solution

A THz measuring device and method that adjusts the focal spot of the THz transmission beam to the specific structures of the corrugated pipe by using a fixed focus or varying focus based on detected structural positions, combined with a detection device for preliminary measurements, allowing precise determination of distances and layer thicknesses, and optionally incorporating multiple THz transceivers for continuous measurement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a fixed THz beam focus is used for measurement, then the measurement setup is simple, but accurate measurement of corrugated pipes with varying structures is not possible

Engineering Contradiction:
Improvemeasurement accuracyVSAvoidmeasurement setup complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent implements dynamic focusing by adjusting the focal spot position of the THz beam along the pipe axis based on the detected corrugation structure positions. The focus is moved to coincide with waves and valleys during scanning, enabling accurate measurement of distance and layer thickness despite the complex corrugated geometry. This dynamic adjustment resolves the contradiction by making the measurement system adaptive to structural variations.

Inventive Principle:
Principle #15Dynamics

2Measurement precision

If the THz beam is focused on the pipe axis, then measurement of smooth pipes is accurate, but measurement of corrugated surfaces at different distances from the axis is inaccurate

Engineering Contradiction:
Improvedistance and layer thickness measurement accuracyVSAvoidadaptability to corrugated structures
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent applies local quality by adjusting the focal spot position to match the local structural characteristics of the corrugated pipe. Instead of maintaining a fixed focus on the pipe axis, the system dynamically repositions the focus to coincide with specific features (waves and valleys) during the scanning process. This ensures that the THz beam interacts optimally with each local structure, enabling accurate measurement of distance and layer thickness at varying positions.

Inventive Principle:
Principle #3Local quality

3Productivity

If manual measurement methods are used for corrugated pipes, then equipment is simple, but measurement efficiency and continuity are low

Engineering Contradiction:
Improvemeasurement efficiencyVSAvoidmeasurement system complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent implements continuous online measurement by integrating the THz measurement system into the pipe production line. The system performs uninterrupted scanning and measurement as pipes are manufactured, enabling real-time process control. This continuous operation dramatically improves productivity compared to manual methods, while the automated nature of the system manages the complexity through integrated control.

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The system incorporates feedback mechanisms where measurement results are immediately used to control and correct production parameters. The real-time data from THz measurements feeds back to the manufacturing process, enabling automated adjustments to maintain quality standards. This feedback loop enhances both productivity and quality while managing system complexity through automation.

Inventive Principle:
Principle #23Feedback

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, efficient, and continuous online measurement of corrugated pipes, allowing for real-time process control and correction of production parameters, thereby improving the quality and efficiency of corrugated pipe manufacturing.

Implementation Method 1

A THz measurement is carried out by emitting and detecting a THz transmission beam and a THz reflection beam

Methodology Applied
Scientific EffectTHz radiation transmission and reflection: Reflection

Implementation Method 2

an optical arrangement, in particular with a lens, is provided in front of the transceiver... The lens can be made of silicon or plastic, for example

Methodology Applied
Scientific EffectOptical focusing: Focusing

Data Source

PatentEP4264175B1Thz measuring device and thz measuring method for performing a measurement on a corrugated pipe
Publication Date: 2025.10.01 CITEX HOLDING GMBH
  • EP4264175B1 patent drawingFigure 1~2
  • EP4264175B1 patent drawingFigure 3~4
  • EP4264175B1 patent drawingFigure 5

AI summary

The invention relates to a THz measuring device and to a THz measuring method for performing a measurement on a corrugated pipe (1). Here, a corrugated pipe (1), the corrugations (2), and valleys (3) formed between the corrugations (2), for example also with fittings (7) and external sleeves (6), is guided in a transport direction (z) through a measurement plane (37) in a measurement chamber of the THz measuring device (20). In a pre-measurement, for example by means of a detection device, for example with a laser, a position or a distance of an outer surface (8) of the corrugated pipe (1) is continuously determined, thereafter, on that basis, a structure (2, 3, 6, 7) of the corrugated pipe (1) is determined in the measurement plane (37), and a focal spot (27) of a THz transceiver (22) along its optical axis (C) is set optionally at a measurement distance (MT) depending on the structure (2, 3, 6, 7) of the corrugated pipe (1) determined in the measurement plane (37). Thereafter or in parallel, a THz measurement is performed by emitting a THz emission beam along the optical axis, focussing on the focal spot and detecting a THz reflection beam (26), and at least one distance of a boundary surface or a layer thickness is determined from the THz measurement.