Differential Dosing Device Pressure Compensation

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Solution Overview

Problem

Pressure fluctuations from process systems negatively affect gravimetric dosing accuracy due to mechanical pressure compensators' inability to fully absorb vertically acting forces, leading to erroneous weight recordings and dosing errors.

Innovation Solution

The pressure compensators in the differential dosing device are rotated 90° to be perpendicular to the load receptors' direction, with horizontally acting compensators arranged between the dosing device and the process system, using a pair of flanges connected via a rigid element to decouple forces, ensuring only horizontal forces affect the scales, thus isolating the weighing signal from pressure influences.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If mechanical pressure compensators are arranged vertically above and below the product discharge point to absorb pressure fluctuations, then pressure compensation is achieved, but the compensators cannot fully absorb all vertically acting forces, resulting in dosing errors

Engineering Contradiction:
Improvepressure compensation effectivenessVSAvoidweighing accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The pressure compensators are rotated 90° from vertical arrangement to horizontal arrangement, changing the spatial dimension of force application. This dimensional change redirects the compensating forces from the vertical direction (parallel to load receptors) to the horizontal direction (perpendicular to load receptors), eliminating interference with weight measurement while maintaining pressure compensation functionality

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

2Reliability

If pressure compensators act in the vertical direction parallel to load receptors, then pressure forces are compensated, but tolerances in mechanical assembly directly affect weighing results

Engineering Contradiction:
Improvepressure decouplingVSAvoidaxis parallelism tolerance
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

By rotating the pressure compensators 90° to arrange them horizontally, the compensating forces act perpendicular to the load receptors rather than parallel. This eliminates the direct transmission of mechanical assembly tolerances (such as axis parallelism and angular fidelity) to the weighing system, as horizontal forces do not affect vertical weight measurements

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

Solution Approach 2:

The horizontal pressure compensators pre-establish a force balance in the horizontal direction that counteracts pressure fluctuations before they can transmit vertical forces to the scales. The rigid connection between flanges creates a predetermined force cancellation mechanism that prevents erroneous signals

Inventive Principle:
Principle #9Preliminary anti-action

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 configuration allows the scales to move freely, canceling out vertical pressure forces and preventing them from affecting the weighing result, resulting in accurate and error-free dosing by eliminating vertical force interference.

Implementation Method 1

pressure compensators are arranged in such a way that the forces from the process system acting on the scales of the dosing system are no longer parallel to the direction of action of the load receptor or load cells of the scales, but are rotated by 90° to it

Methodology Applied
Scientific EffectPressure compensation:

Implementation Method 2

Both flanges are connected to each other via a rigid connection. A vertical pressure compensator also connects to this second flange. The second side of each pressure compensator is connected to the housing of the ejection unit. This structure leads to force decoupling in the ejection unit.

Methodology Applied
Scientific EffectForce decoupling:

Data Source

PatentEP3945295B1Differential dosing device
Publication Date: 2023.08.16 HOSOKAWA ALPINE AG
  • EP3945295B1 patent drawingFigure 1

AI summary

In a pressure compensation device for a differential dosing unit connected to a process system via a discharge unit, vertically acting forces from the process system are to be compensated so that they do not affect the gravimetric dosing and negatively influence it. This is achieved by the dosing device having a flange at its discharge point, which, via a connecting piece, has a second, parallel flange opposite it, with the flanges being connected to the discharge chute via a ring compensator.