Distance Tube for Fluidisable Material Feeding

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Solution Overview

Problem

Existing feeders for powder materials, such as alumina and fluoride, face high variance in dosages due to hydrostatic effects, which is particularly challenging when dosing small quantities, leading to inaccurate delivery.

Innovation Solution

The introduction of a distance tube between the reservoir and the discharging air-slide, with a specific height-to-diameter ratio, minimizes hydrostatic effects by creating a consistent angle of repose and pressure distribution, allowing for accurate dosage independent of the filling level.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a conventional feeder design with a control volume is used, then the structure is relatively simple, but the dosage accuracy deteriorates due to high variance caused by hydrostatic effects

Engineering Contradiction:
Improvedosage accuracyVSAvoidfeeder structure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The feeder is divided into functionally independent sections: a reservoir for material storage, a distance tube for hydrostatic isolation, and a discharging air-slide for precise material delivery. This segmentation allows each component to perform its specific function optimally, with the distance tube specifically designed to eliminate hydrostatic effects that would otherwise compromise dosage accuracy.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The distance tube acts as an intermediary element between the reservoir and the discharging air-slide. It serves as a mediator that transmits material while isolating the discharging section from hydrostatic pressure variations in the reservoir, thereby enabling accurate dosing independent of filling level.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If the filling level in the reservoir varies, then the hydrostatic pressure changes, but this causes high variance in dosages leaving the apparatus

Engineering Contradiction:
Improveoperational flexibilityVSAvoiddosage consistency
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The distance tube creates a pressure equilibrium condition at its outlet by being sufficiently long and narrow, ensuring that the pressure at the outlet remains constant regardless of the filling level in the reservoir. This equipotential effect at the tube outlet eliminates the harmful influence of hydrostatic pressure variations on dosage consistency.

Inventive Principle:
Principle #12Equipotentiality

Solution Approach 2:

The distance tube replicates the material flow conditions while isolating them from pressure variations. By creating a controlled flow path that copies the material properties without transmitting hydrostatic pressure effects, the system achieves consistent dosing despite variations in reservoir filling level.

Inventive Principle:
Principle #26Copying

3Measurement precision

If a distance tube with specific height-to-diameter ratio is introduced, then dosage accuracy improves significantly, but the device occupies more vertical space

Engineering Contradiction:
Improverelative standard deviation reductionVSAvoidfeeder height
Core Design Contradiction:
Measurement precisionVSLength of stationary object

Solution Approach 1:

The distance tube utilizes the vertical dimension strategically to achieve its function. By orienting the tube vertically and designing it with specific dimensional ratios, the system eliminates hydrostatic effects without requiring additional horizontal space, thus resolving the contradiction between accuracy improvement and space occupation.

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

4Stability of the object's composition

If the distance tube creates a consistent angle of repose, then pressure distribution becomes uniform, but the tube requires specific geometric proportions

Engineering Contradiction:
Improvepressure distribution uniformityVSAvoidgeometric specification requirements
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The invention specifies critical geometric parameters for the distance tube, particularly the height-to-diameter ratio, to ensure proper functioning. By defining these parameters within specific ranges, the system achieves uniform pressure distribution and consistent angle of repose without requiring overly complex geometric configurations.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3194313B1Method for feeding doses of fluidisable materials
Publication Date: 2020.06.10 NORSK HYDRO ASA
  • EP3194313B1 patent drawingFigure 1a~1b
  • EP3194313B1 patent drawingFigure 2a~2b
  • EP3194313B1 patent drawingFigure 3a~3b

AI summary

Means and a method for feeding doses of fluidisable materials, comprising a supply of material (1, 2, 2') and a discharging air slide (3) with at least one fluidisable element (5) in its bottom, where said element, when activated, being able to transport material towards one outlet (8) for controlled dosage. Upstream the discharging air slide (3) there is arranged a substantially vertical distance tube (4, 4') that connects the supply of material (1, 2, 2') with the discharging air slide (3). The distance tube has a height to diameter ratio that will ensure a constant hydrostatic pressure towards the discharging air slide (3) at different filling levels.