Backscatter Sensor Biconvex Lens Shielding Element

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Solution Overview

Problem

Existing backscatter sensors face challenges in achieving accurate measurements of liquid, pasty, and powdery media due to susceptibility to errors from soiling and air bubbles, and require a compact design that limits the detection range.

Innovation Solution

A backscatter sensor design featuring a biconvex lens shielding element that protrudes into the medium, allowing for direct contact and reducing adhesion of dirt and air bubbles, with a compact configuration that includes a light source and detector positioned close to the first convex surface and a measuring beam path that avoids additional optical elements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a flat shielding element is used to prevent medium contact, then the sensor is protected from contamination, but adhesion of dirt particles and air bubbles increases causing measurement errors

Engineering Contradiction:
Improvesensor protection from contaminationVSAvoidmeasurement accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent applies curvature by designing the shielding element with a convex surface that protrudes into the medium. This curved geometry prevents dirt particles and air bubbles from adhering to the shielding element, as they cannot become trapped in convex surfaces. The convex surface allows the medium to flow smoothly over it, maintaining optical clarity while still protecting the sensor internally from direct contact with the medium.

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Measurement precision

If the shielding element protrudes into the medium, then detection range increases and adhesion is reduced, but the risk of contamination increases

Engineering Contradiction:
Improvedetection rangeVSAvoidcontamination risk
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The convex surface of the shielding element protrudes into the medium to extend the detection range closer to the sensor. The curved geometry is specifically designed to prevent adhesion of contaminants while maintaining this extended range. The convex shape ensures that dirt particles and air bubbles are swept away by the medium flow rather than being trapped, thus reducing contamination risk while improving measurement capability.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent extracts the convex surface from the main sensor body, creating a separate shielding element that can be optimally shaped and positioned. This allows the convex surface to protrude into the medium for extended detection range while the main sensor body remains protected. The shielding element acts as an independent component that can be designed with optimal curvature to prevent contamination.

Inventive Principle:
Principle #2Taking out (Extraction)

3Volume of moving object

If a compact design is implemented to minimize feed tube diameter, then installation space is reduced, but optical alignment becomes more difficult

Engineering Contradiction:
Improvesensor sizeVSAvoidoptical alignment complexity
Core Design Contradiction:
Volume of moving objectVSDevice complexity

Solution Approach 1:

The patent combines the shielding element with optical focusing functionality by designing it as a biconvex lens. This merging of protective shielding and optical focusing functions into a single component eliminates the need for separate alignment adjustments. The lens geometry is optimized to automatically focus the measuring beam and collect backscattered light, reducing the number of adjustable components and simplifying the overall optical system while maintaining compact dimensions.

Inventive Principle:
Principle #5Merging (Combining)

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 enhances measurement accuracy and extends the detection range deeper into the medium, while maintaining a cost-effective and structurally simple setup, reducing errors and the need for complex optical alignments.

Implementation Method 1

The shielding element is designed as a biconvex lens... enables a beam path, allowing radiation reflected in the medium from a region located close to the second convex surface of the shielding element to be detected

Methodology Applied
Scientific EffectRefraction: Refraction

Implementation Method 2

the second convex surface reduces the adhesion of dirt particles and other optically interfering elements, such as air bubbles

Methodology Applied
Scientific EffectSurface tension: Surface Tension

Implementation Method 3

a light source for emitting a measuring beam... a detector for detecting the measuring beam that is at least partially reflected by the medium to be measured

Methodology Applied
Scientific EffectOptical scattering: Scattering

Data Source

PatentEP3388817B1Backscatter sensor for liquid, pasty and/or powdered media and method for measuring optical backscattering in liquid, pasty and/or powdery media
Publication Date: 2020.05.13 EXNER & TOTTEWITZ BESITZ
  • EP3388817B1 patent drawingFigure 1
  • EP3388817B1 patent drawingFigure 2
  • EP3388817B1 patent drawingFigure 3

AI summary

The invention relates to a backscatter sensor for liquid, pasty, and/or powdery media, comprising a light source for emitting a measuring beam, a detector for detecting the measuring beam at least partially reflected by the medium to be measured, and a liquid-tight optical shielding element for shielding the light source and the detector from the medium to be measured. The invention is characterized in that the shielding element is designed as a biconvex lens, with at least one first convex surface facing the light source and the detector, and at least one second convex surface facing the liquid to be measured in the measuring configuration, wherein the backscatter sensor is designed for direct contact between the second convex surface and the medium to be measured in the measuring configuration.The invention further relates to a method for measuring optical backscattering in liquid, pasty and/or powdery media and the use of an optical element.