Dosing Weighing Device Pressure Compensation

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Solution Overview

Problem

Dosing and weighing devices for bulk goods face accuracy issues due to pressure fluctuations caused by cyclic actuation and product flow, which can lead to contamination risks, especially in hygienic environments like the food or pharmaceutical sectors, where traditional ventilation openings are inadequate.

Innovation Solution

A dosing and weighing device that determines and corrects for pressure differences between upstream and downstream of the weighing surface using a pressure difference sensor, ensuring a closed system operation and improved accuracy by compensating for pressure fluctuations without external ventilation openings.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If ventilation openings are provided to counteract pressure fluctuations, then pressure stability is improved, but contamination risk increases

Engineering Contradiction:
Improvepressure stabilityVSAvoidcontamination risk
Core Design Contradiction:
Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The patent converts the harmful pressure fluctuations into a measurable signal that can be compensated for electronically. Instead of trying to prevent pressure changes through ventilation openings (which would allow contamination), the system measures the pressure difference using a differential pressure sensor and uses this information to correct weight measurements digitally, thus eliminating the need for physical ventilation while maintaining measurement accuracy.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

2Object-affected harmful factors

If a closed system is used to prevent contamination, then hygiene is improved, but pressure fluctuation compensation becomes difficult

Engineering Contradiction:
Improvecontamination protectionVSAvoidpressure stability
Core Design Contradiction:
Object-affected harmful factorsVSStability of the object's composition

Solution Approach 1:

The patent introduces a differential pressure sensor as an intermediary element that allows the closed system to 'sense' pressure differences without being opened. This mediator provides the necessary pressure information for compensation while maintaining the integrity and closed nature of the system, thus achieving both hygiene and pressure stability.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If pressure difference measurement and correction is implemented, then weight measurement accuracy is improved, but device complexity increases

Engineering Contradiction:
Improveweight measurement accuracyVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical pressure compensation mechanisms (such as ventilation openings, filters, or movable components) with a simple electronic/digital correction approach. By using a differential pressure sensor to measure pressure differences and then applying a digital correction to the weight measurement, the system achieves high accuracy without adding significant mechanical complexity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 enhances the operational hygiene and stability of the dosing and weighing device, providing more accurate and faster weight determination while maintaining a closed system, reducing contamination risks and improving process stability.

Implementation Method 1

Means for determining a pressure difference between a pressure in the product flow upstream and a pressure in the product flow downstream of the weighing surface are arranged

Methodology Applied
Scientific EffectPressure difference measurement: Pressure Gradient

Implementation Method 2

A weight of the product resting on the weighing surface can thus be determined by means of the at least one weight sensor

Methodology Applied
Scientific EffectWeight measurement: Force

Data Source

PatentEP3491347B1Dosing and weighing device and method for determining the weight of a product in a dosing and weighing device
Publication Date: 2020.02.12 BUHLER AG
  • EP3491347B1 patent drawingFigure 1
  • EP3491347B1 patent drawingFigure 2

AI summary

The invention relates to a dosing and weighing device (1), comprising a housing (2) having an inlet opening (3) and an outlet opening (4), and a weighing surface (5), which is operatively connected to at least one weight sensor (7), means (9) for detecting a pressure difference between a pressure in the housing upstream and a pressure in the housing downstream of the weighing surface (5). By means of a control unit (8), the detected pressure difference is used to correct the weight detected by the weight sensor (7).