Rotating Inner Diameter Measurement Device

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Solution Overview

Problem

Existing inner diameter measuring devices for hollow members require rotation of the pipe to be measured, leading to errors and a complex structure, and are limited to measuring restricted portions, especially for long pipes.

Innovation Solution

An inner diameter measuring device with a circulation unit and a measuring head that is insertable into the hollow object, featuring a contact measuring unit, an advancing/retreating unit, and a scale unit, allowing the measuring head to rotate around the center line without requiring the pipe to be rotated, enabling accurate measurement of the inner diameter over the entire circumference and length.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a jig is brought into contact with the inner surface of the pipe and a probe is brought into contact with the jig to measure displacement, then the inner diameter can be measured, but the measurement contains error caused by interposition of the jig and can only be performed on restricted portions

Engineering Contradiction:

Improvemeasurement accuracyVSAvoidmeasurement system complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent removes the intermediate jig from the measurement system. Instead of using a probe that contacts the jig, the invention uses a contactless measurement method where the measurement unit directly measures the inner surface of the pipe through electromagnetic induction, eliminating the error source caused by jig interposition

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical contact measurement system (probe-jig-contact) with an electromagnetic field-based measurement system. The measurement unit generates an electromagnetic field that interacts with the conductive pipe wall, allowing non-contact measurement and eliminating mechanical interference

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Productivity

If the pipe to be measured is rotated to enable measurement, then the inner diameter can be measured along the length, but the structure becomes complicated and the device must be designed in large scale

Engineering Contradiction:

Improvemeasurement coverageVSAvoidsystem structure complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

Instead of rotating the pipe to achieve measurement coverage, the patent inverts the approach by making the measurement unit rotatable. The measurement unit rotates within the stationary pipe, allowing comprehensive measurement of the inner diameter along the entire length without requiring pipe rotation or complex external support structures

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent employs a nested structure where the rotatable measurement unit is contained within the measurement tube, which itself is inserted into the pipe. This nested arrangement allows the compact measurement unit to rotate freely inside the pipe without requiring external rotation mechanisms or large-scale device design

Inventive Principle:

Principle #7Nested doll (Nesting)

3Measurement precision

If the measurement unit is permanently biased to be in contact with the inner wall of the tube and rotated, then the interior profile can be sensed, but the pipe must be rotated leading to errors and complex structure

Engineering Contradiction:

Improveprofile sensing accuracyVSAvoidoperation simplicity

Core Design Contradiction:

Measurement precisionVSEase of operation

Solution Approach 1:

The patent inverts the traditional approach by making the measurement unit rotatable instead of rotating the pipe. The measurement unit with its contactless probe rotates within the stationary pipe, maintaining continuous contactless measurement of the inner profile while simplifying operation and eliminating errors associated with pipe rotation

Inventive Principle:

Principle #13The other way round (Inversion)

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 solution allows for precise and comprehensive measurement of inner diameters without rotating the pipe, reducing errors and complexity, and enabling measurement of long pipes without the need for a large-scale device design.

Implementation Method 1

a contact measuring unit for measuring an amount of displacement of contacts, which is displaced by contacting an inner surface of the object to be measured

Methodology Applied

Scientific EffectMechanical contact displacement detection:

Implementation Method 2

a scale unit, and wherein the scale unit comprises a scale sensor movable integrally with the measuring unit holder, and a linear scale provided in parallel to moving direction of the contact measuring unit

Methodology Applied

Scientific EffectLinear scale displacement measurement:

Data Source

PatentEP2813800B1Inside-diameter measurement device

Publication Date: 2019.10.02 IHI CORP

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AI summary

An inner diameter measuring device (50) for measuring an inner diameter of a hollow object to be measured, wherein the inner diameter measuring device comprises a circulation unit (1) and a measuring head (2) and is insertable into inside of an object to be measured, wherein the measuring head has a contact measuring unit (27) for measuring the inner diameter by contacting an inner surface of the object to be measured and an advancing/retreating unit (23) for making the contact measuring unit to advance and to retreat in a radial direction, and wherein the circulation unit can rotate the measuring head around a center line (51) of the inner diameter measuring device.