Ultrasonic Fill Level Sensor Flow Damper Design

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Solution Overview

Problem

Existing devices for determining the fill level of a medium in collecting containers, such as oil or fuel, face inaccuracies due to medium foaming and the formation of gas bubbles, which can lead to unreliable measurements caused by Schlichting flow and pressure fluctuations.

Innovation Solution

A device with a flow damper in the antechamber, featuring a surface element with deflection surfaces and protruding damping bodies, is used to minimize undesirable flows and vortices, ensuring that currents do not adversely affect the measuring chamber's liquid level, and multiple antechambers connected in series are employed to further calm the medium and eliminate gas bubbles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the measuring chamber is preceded by an antechamber to calm the medium and eliminate gas bubbles, then the measurement reliability is improved, but the device complexity increases due to the additional chamber and flow damper structure

Engineering Contradiction:
Improvemeasurement reliabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The device is segmented into distinct functional zones: an antechamber for medium calming and gas bubble elimination, and a measuring chamber for accurate level measurement. The flow damper is further segmented into multiple damping bodies arranged in series, each contributing to flow stabilization. This segmentation allows independent optimization of each zone's function while maintaining overall system reliability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The flow damper acts as an intermediary element between the antechamber and measuring chamber. It mediates the transition of the medium by dissipating kinetic energy and eliminating residual vortices before the medium enters the measuring chamber, thereby protecting the measurement process from flow-induced disturbances without requiring complete redesign of the overall system.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If a flow damper with multiple damping bodies is introduced to eliminate Schlichting flow and pressure fluctuations, then the measurement precision is improved, but the manufacturing complexity increases

Engineering Contradiction:
Improvemeasurement precisionVSAvoidease of manufacture
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The flow damper incorporates damping bodies with locally optimized geometries positioned at specific locations within the antechamber. Each damping body has a tailored cross-sectional area and shape designed to address local flow conditions and eliminate vortices in specific regions. This local quality approach maximizes measurement precision while avoiding the need for complete redesign of the entire flow path.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The damping bodies are designed with varying cross-sectional areas along their length, creating a gradient of resistance to flow. This parameter change allows progressive dissipation of flow energy, effectively eliminating Schlichting flow and pressure fluctuations. The gradual parameter change also simplifies manufacturing compared to abrupt geometric transitions, as it can be achieved through standard machining or molding processes.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If the antechamber is designed with a vent extending over the medium surface to eliminate gas bubbles, then the measurement accuracy is improved, but the device complexity increases due to additional structural elements

Engineering Contradiction:
Improvemeasurement accuracyVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The antechamber structure serves multiple functions simultaneously: it calms the incoming medium, eliminates gas bubbles through the vent, and houses the flow damper elements. The vent itself serves dual purposes by allowing gas bubble escape while also defining the upper boundary of the measurement region. This multi-functionality reduces the need for separate components, thereby limiting the increase in device complexity while maintaining measurement accuracy.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP2482046B1Device for determining a fill level of a medium
Publication Date: 2016.02.24 HELLA GMBH & CO KGAA
  • EP2482046B1 patent drawingFigure 1~2
  • EP2482046B1 patent drawingFigure 3~4

AI summary

The device comprises a measuring chamber (2) conductively connected to a media collection container, where an ultrasonic sensor is arranged in the measuring chamber, and a prechamber (3) upstream of the measuring chamber. The prechamber comprises an inlet port (5) for the media from the collection container. A flow damper is arranged for the medium in a partial region of the prechamber. The prechambers are connected with the measuring chamber connected with the conducting medium and are fitted with the flow damper. Each flow damper is arranged in an inlet area of the respective prechamber. The device comprises a measuring chamber (2) conductively connected to a media collection container, where an ultrasonic sensor is arranged in the measuring chamber, and a prechamber (3) upstream of the measuring chamber. The prechamber comprises an inlet port (5) for the medium from the collection container. A flow damper is arranged for the medium in a partial region of the prechamber. The prechambers are connected with the measuring chamber connected with the conducting medium and are fitted with the flow damper. Each flow damper is arranged in an inlet area of the respective prechamber. One of the flow dampers is formed as a permeable material structure, a flowable contour part or a surface element (8), which comprises a deflection surface with an overflow edge. The surface element exhibits damping bodies on one of its deflection surfaces. Each damping body exhibits a cross-section changing in the direction.