Oscillating Screw Metering Duct for Gentle Powder Handling

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Solution Overview

Problem

Conventional metering systems for free-flowing materials, such as pharmaceutical powders and granular materials, often result in quality reduction and dust formation due to shearing loads, making them unsuitable for sensitive materials and difficult to maintain and clean.

Innovation Solution

A metering apparatus with a screw-shaped metering duct that undergoes an oscillating rotary motion about its vertical axis, minimizing shearing loads by using a closed cross section and controlled acceleration phases to gently discharge material without mechanical relative motions, reducing abrasion and dust formation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional auger fillers or slide fillers are used for metering, then metering function is achieved, but material quality is reduced and dust is formed due to shearing loads

Engineering Contradiction:

Improvemetering functionVSAvoidmaterial quality reduction and dust formation

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the conventional mechanical shearing-based metering system with an oscillating motion system. The metering duct is set in oscillating motion with individual rotary strokes, utilizing centrifugal force and gravity to discharge material through a lower discharge opening, thereby avoiding shearing loads and their harmful effects on material quality and dust formation

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the motion parameters of the metering duct from continuous rotation or linear movement to oscillating rotary motion with specific acceleration phases. The oscillating motion includes an acceleration phase that intensifies contact pressure force and a deceleration phase that loosens the powder, enabling controlled discharge without shearing

Inventive Principle:

Principle #35Parameter changes

2Productivity

If conventional metering systems with shearing loads are used, then material is conveyed and metered, but abrasion and dust formation increase

Engineering Contradiction:

Improvematerial conveyance and meteringVSAvoidabrasion and dust formation

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent substitutes the shearing-based mechanical conveyance system with an oscillating conveyance system. The entire metering duct oscillates as a unit, using centrifugal force during acceleration phases to press material against the duct wall and gravity during deceleration phases to allow material to fall out, eliminating relative shearing motion and associated abrasion and dust generation

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If conventional metering systems are used, then metering is performed, but maintenance and cleaning works are difficult under closed-off containment conditions

Engineering Contradiction:

Improvemetering operationVSAvoidmaintenance and cleaning accessibility

Core Design Contradiction:

ReliabilityVSEase of repair

Solution Approach 1:

The patent divides the metering system into separable components: the metering duct can be detached from the housing, and the oscillating drive mechanism is positioned for easy access. This segmentation allows the metering duct to be removed and cleaned externally without requiring disassembly of the entire containment system, significantly improving maintenance accessibility

Inventive Principle:

Principle #1Segmentation

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 solution enables precise and gentle metering of sensitive materials with reduced environmental pollution and easier maintenance, maintaining the quality of the materials and facilitating use in closed containment systems.

Implementation Method 1

Upon a rotary acceleration against the pitch of the metering duct, the contact pressure force of the material against the base is intensified... Upon the rotary acceleration in the opposite direction, the contact pressure force diminishes, however, which results in a loosening of the powder

Methodology Applied

Scientific EffectCentrifugal force: Centrifugal Force

Implementation Method 2

in the acceleration-free phase, the material to be metered rests by virtue of its weight on the oblique bottom surface of the helical metering duct

Methodology Applied

Scientific EffectGravity: Gravitation

Data Source

PatentUS11648183B2Metering apparatus and method for operating a metering apparatus

Publication Date: 2023.05.16 HARRO HOFLIGER VERPACKUNGSMASCHEN

AI summary

The disclosure relates to a metering apparatus for free-flowing material and to a method for operating such a metering apparatus. The metering apparatus has a metering duct having a closed cross section and further has a rotary drive (M). The metering duct is wound in the form of a screw with a vertical longitudinal axis. The free-flowing material is fed to the metering duct. The metering duct is set via the rotary drive (M) in an oscillating rotary motion about its longitudinal axis with individual rotary strokes, wherein, with each rotary stroke, a partial quantity of the free-flowing material falls out of a lower discharge opening of the metering duct.