Capacitive Fill Level Sensor with Elastic Coupling for Drainage Pump

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Solution Overview

Problem

Drainage pump systems face increased costs and reduced accuracy due to the attachment of level sensors on fluid collection containers, which are not hygienic for repeated use, and sensors attached to the drainage pump unit are less accurate, especially with small fluid quantities.

Innovation Solution

A drainage pump unit with a flat band-shaped capacitive fill level sensor on the suction pump housing and an elastically designed coupling element that eliminates air gaps between the sensor and fluid collection container, allowing for accurate level measurement and optional inclination detection without separate sensors, enabling cost-effective disposable containers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If level sensors are attached to the fluid collection container, then measurement precision is improved, but device complexity and cost increase

Engineering Contradiction:
Improvelevel measurement accuracyVSAvoidsensor attachment complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces a coupling element as an intermediary component between the level sensor and the fluid collection container. This coupling element enables accurate level measurement by eliminating air gaps while keeping the sensor integrated into the pump housing rather than attached to the disposable container, thus resolving the contradiction between measurement precision and device complexity

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system is segmented into permanent components (pump housing with integrated sensor and coupling element) and disposable components (fluid collection container). This segmentation allows the expensive, complex sensor assembly to be reused while the container is discarded, maintaining measurement precision without increasing overall system complexity for each disposable unit

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If level sensors are attached to the fluid collection container, then measurement precision is improved, but manufacturing cost increases

Engineering Contradiction:
Improvelevel measurement accuracyVSAvoidmanufacturing cost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent applies the disposable principle to the fluid collection container while keeping the expensive level sensor integrated into the reusable pump housing. The coupling element bridges the sensor and container without requiring the sensor to be attached to the disposable unit, thereby maintaining measurement precision while reducing manufacturing costs for each disposable container

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The coupling element serves multiple functions: it mechanically connects the container to the pump housing, eliminates air gaps for accurate sensing, and provides a reusable interface that works with multiple disposable containers. This multi-functionality reduces the need for separate components and lowers overall manufacturing costs

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

3Reliability

If the coupling element is made elastic, then reliability is improved through maintained contact, but manufacturing precision requirements increase

Engineering Contradiction:
Improvesensor contact reliabilityVSAvoidcoupling element geometry precision
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent changes the physical parameter of the coupling element from rigid to elastic, allowing it to deform and maintain reliable contact with the fluid collection container despite manufacturing tolerances or container variations. This elasticity compensates for dimensional variations without requiring extremely tight manufacturing precision

Inventive Principle:
Principle #35Parameter changes

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

The solution enhances measurement accuracy for small fluid quantities, maintains sensor functionality after multiple container changes, and simplifies cleaning and protection of the sensor, allowing for cost-effective, disposable fluid collection containers.

Implementation Method 1

capacitive fill level sensor (4) arranged on the suction pump housing (1) for detecting a fill level in the fluid collection container (2)

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 2

flat band-shaped capacitive fill level sensor (4)

Methodology Applied
Scientific EffectDielectric: Dielectric

Implementation Method 3

elastically designed coupling element (3) with a first surface and a second surface opposite the first surface, wherein in the attached state of the fluid collection container (2), the coupling element (3) rests with the first surface on the fill level sensor (4) and with the second surface on an outer wall of the fluid collection container (2)

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2496276B1Drainage pump unit
Publication Date: 2013.08.28 MEDELA HLDG AG
  • EP2496276B1 patent drawingFigure 1
  • EP2496276B1 patent drawingFigure 2
  • EP2496276B1 patent drawingFigure 3~7

AI summary

The invention relates to a drainage pump unit for vacuuming bodily fluids by means of a suction pump, comprising a suction pump housing (1) and a suction pump arranged therein. A fluid collection container (2) can be detachably fastened to the suction pump housing (1). A flat-band-shaped capacitive fill level sensor (4) is arranged on the suction pump housing (1) in order detect a fill level in the fluid collection container (2). The drainage pump unit further comprises an elastic coupling element (3) having a first surface and a second surface lying opposite from the first surface, wherein the coupling element (3) lies against the fill lever sensor (4) at the first surface and against an outer wall of the fluid collection container (2) at the second surface when the fluid collection container (2) is in the fastened state. Due to the elastic coupling element, said drainage pump unit allows the fill level to be measured even at small filling amounts.