Self-Cleaning Optical Probe with Central Aperture

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Solution Overview

Problem

Conventional ultrasonic probes for oil-in-water sensors face issues with poor energy transmission, unstable impedance matching, and heat-related damage to optical fibers and cables due to the side entry slot for ultrasonic transmission, leading to fouling and resonance instability.

Innovation Solution

An optical probe design with an elongate hollow body featuring an internal chamber for optical sensors, an ultrasonic transducer at one end for self-cleaning, and a hollow bolt for secure mounting, allowing optical fibers and cables to pass through the transducer's central aperture, eliminating the need for a side entry slot and ensuring efficient energy transmission and protection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a side entry slot is provided in the probe shaft for passing optical fibres and cables, then device insertion is enabled, but ultrasonic energy transmission deteriorates and heat generation occurs

Engineering Contradiction:
Improvedevice insertionVSAvoidultrasonic energy transmission
Core Design Contradiction:
Ease of operationVSLoss of energy

Solution Approach 1:

The invention moves the entry point for optical fibres and cables from the side of the probe shaft to the distal end, changing the spatial dimension of the entry slot. This allows cables to enter through the distal end of the hollow probe shaft rather than through a side slot, eliminating the impedance path while maintaining ease of insertion.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The invention extracts the entry slot for optical fibres from the side of the probe shaft and relocates it to the distal end. This separation removes the harmful interaction between the entry slot and ultrasonic transmission path, allowing ultrasonic energy to transmit efficiently through the probe shaft wall without being absorbed by the entry slot.

Inventive Principle:
Principle #2Taking out (Extraction)

2Ease of operation

If a side entry slot is provided in the probe shaft, then optical fibres can be inserted, but impedance matching becomes unstable

Engineering Contradiction:
Improveoptical fibre insertionVSAvoidimpedance matching
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

The entry point for optical fibres is relocated from the side of the probe shaft to the distal end, changing the spatial configuration. This eliminates the high impedance path created by the side slot, allowing stable impedance matching throughout the ultrasonic transmission path from transducer to measurement window.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Ease of operation

If a side entry slot is provided for cable passage, then device installation is enabled, but heat generation damages optical fibres and cables

Engineering Contradiction:
Improvecable passageVSAvoidheat generation
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The entry slot for cables is extracted from the side of the probe shaft and relocated to the distal end. This removes the source of heat generation (the high impedance absorption at the side slot) from the path of optical fibres and cables, preventing heat-related damage while maintaining cable passage capability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The hollow probe shaft structure acts as an intermediary, providing a protected pathway for optical fibres and cables from the distal end to the external environment. This hollow structure allows cable insertion while isolating them from the ultrasonic transmission path and preventing heat generation at the entry point.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Power

If ceramic transducer discs are mounted on the probe shaft, then ultrasonic vibration is generated, but energy transmission is poor without proper impedance matching

Engineering Contradiction:
Improveultrasonic vibration generationVSAvoidenergy transmission
Core Design Contradiction:
PowerVSLoss of energy

Solution Approach 1:

The probe shaft is designed with uniform material composition and continuous structure, eliminating discontinuities such as side entry slots that create impedance mismatches. This homogeneous construction ensures efficient energy transmission from the ceramic transducer discs through the probe shaft wall to the measurement window, minimizing energy loss.

Inventive Principle:
Principle #33Homogeneity

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 design provides stable and efficient ultrasonic energy transmission, prevents heat-related damage, and simplifies device insertion and maintenance, ensuring a clean and stable measurement window for accurate oil-in-water sensing.

Implementation Method 1

The window will be cleaned by the ultrasonic cavitations created by the ultrasonics

Methodology Applied
Scientific EffectUltrasonic cavitation: Acoustic Cavitation

Implementation Method 2

an optical window being provided at a first end of the hollow body, said optical window defining a wall of said internal chamber for transmitting light therethrough

Methodology Applied
Scientific EffectLight transmission: Light

Implementation Method 3

said ultrasonic transducer is secured to the first end of said elongate body by means of a fastener passing therethrough, said fastener being provided with a hole defining said entry aperture

Methodology Applied
Scientific EffectMechanical fastening: Mechanical Fastener

Data Source

PatentEP2490831B1Self cleaning optical probe
Publication Date: 2013.12.18 ADVANCED SENSORS
  • EP2490831B1 patent drawingFigure 1~4

AI summary

An optical probe comprising an elongate hollow body having an internal chamber for receiving an optical sensor and/or an light emission device, such as one or more optical fibres, an optical window being provided at a first end of the hollow body, said optical window defining a wall of said internal chamber for transmitting light therethrough, and an ultrasonic transducer provided at a second end of the elongate body opposite said first end for cleaning said optical window via ultrasonic vibrations, wherein said ultrasonic transducer is provided with an entry aperture extending through the ultrasonic transducer, through which entry aperture optical fibres, cables or wires may pass to enter said internal chamber