Magnet-Based Cable Length Measurement for Sewer Systems

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Solution Overview

Problem

Sewer inspection and maintenance systems face challenges in accurately determining the conveyed length of cables or push eels due to variations in diameter, friction, and adhesion properties, leading to slippage and subsequent wear, heat generation, and positional inaccuracies.

Innovation Solution

A measuring device with a compensation device featuring a rotatably mounted magnet and magnetic field sensor, which detects rotations caused by the cable's advance, ensuring accurate length measurement and compensating for radial movements, and can be used in conjunction with two devices to average measurements and reduce errors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the cable is transported using a propulsion device with wheels or belts, then the cable can be advanced along the sewer, but slippage occurs between the cable and propulsion system resulting in wear and inaccurate position determination

Engineering Contradiction:

Improvecable advancement capabilityVSAvoidposition determination accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The patent replaces the mechanical friction-based propulsion system with a magnetic field-based measurement system. A magnet is mounted on the cable and a magnetic sensor on the propulsion device detects the magnet's position and movement, allowing accurate measurement of cable advancement without relying on friction between the cable and propulsion components.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces a magnet as an intermediary element between the cable and the propulsion device. The magnet moves with the cable while the magnetic sensor detects its position, serving as a mediator that enables non-contact measurement of cable movement and eliminates the need for direct mechanical contact for measurement purposes.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If the cable is transported using a propulsion device, then the cable can be advanced along the sewer, but heat generation occurs due to sliding friction leading to cable and propulsion system overheating

Engineering Contradiction:

Improvecable advancement capabilityVSAvoidcable and propulsion system temperature

Core Design Contradiction:

ProductivityVSTemperature

Solution Approach 1:

The patent replaces the friction-based mechanical propulsion system with a magnetic field-based system. By eliminating direct friction between the cable and propulsion device through the use of magnetic field interaction, the system avoids the heat generation that would otherwise occur from sliding friction, thereby preventing overheating of both the cable and propulsion components.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Adaptability or versatility

If the cable diameter changes along its length due to crushing, then the cable can be transported through the propulsion system, but the friction or adhesion properties change constantly affecting measurement accuracy

Engineering Contradiction:

Improvecable diameter variation toleranceVSAvoidfriction and adhesion property consistency

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent replaces the friction-based measurement approach with a magnetic field-based approach. By using a magnet mounted on the cable and a magnetic sensor on the propulsion device, the system measures cable movement through magnetic field interaction rather than friction, thereby eliminating the problem of varying friction and adhesion properties caused by cable diameter changes and crushing.

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 solution provides reliable and accurate measurement of cable length, reduces slippage and wear, and prevents overheating, ensuring precise positioning and safe operation, especially in explosive environments.

Implementation Method 1

a magnetic field sensor, wherein the cable can be guided past the compensating device during the advance of the cable, the at least one rotatably mounted magnet is arranged on the magnet holder in such a way that rotations of the at least one rotatably mounted magnet about the axis of rotation can be effected by the advance of the cable

Methodology Applied

Scientific EffectMagnetic field detection: Magnetic Field

Data Source

PatentEP3988892B1Meter counter

Publication Date: 2024.09.18 IPEK INT

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AI summary

A measuring device (10) is provided for measuring the feed rate of a cable (2) of a sewer cleaning and/or sewer inspection system. A rotatably mounted magnet (50; 50') is designed such that the feed rate of the cable (2) causes rotations of the magnet (50; 50'), the magnet following a movement of the cable (2) in a radial direction during the cable feed rate. A corresponding method is also provided.