Mass-Based Metering Device for Precise Liquid Preparation Dispensing
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Solution Overview
Problem
Existing machines for making liquid preparations, such as coffee or soup, often dispense inconsistent volumes due to factors like water hardness, pump wear, and incorrect ingredient placement, leading to inaccurate dosing.
Innovation Solution
A metering device with a mass sensor under the liquid reservoir continuously measures the mass of the liquid, allowing for precise correlation and adjustment of the pump operation time to ensure the correct volume of liquid preparation is dispensed, accounting for vaporization losses and machine conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If open-loop operation with timer control is used, then device complexity is reduced, but manufacturing precision deteriorates due to inconsistent volume dispensing
Solution Approach 1:
The patent implements feedback control by continuously measuring the mass of liquid dispensed using a load cell sensor and comparing it against the target volume. The system adjusts the pump operation in real-time based on the measured mass, ensuring accurate volume dispensing despite variations in pump performance or liquid properties.
Solution Approach 2:
The patent replaces mechanical flow measurement methods (such as flowmeters or optical sensors) with a mass-based measurement system using a load cell. This substitution provides more accurate and reliable measurement of the dispensed volume by directly measuring mass and converting it to volume using density compensation.
2Manufacturing precision
If mass measurement with continuous monitoring is implemented, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The load cell serves multiple functions: it measures the mass of the liquid reservoir, monitors the mass of dispensed liquid, and provides data for both control and protection functions. This multi-functionality reduces the need for separate measurement devices, thereby limiting the increase in device complexity.
Solution Approach 2:
The system uses the existing liquid reservoir and pump infrastructure, adding only the minimal necessary components (load cell and control logic). The mass measurement system integrates with the existing open-loop control architecture rather than requiring a complete system redesign.
3Manufacturing precision
If pump operation time is extended to compensate for wear, then volume dispensing precision is maintained, but loss of time increases due to longer cycle duration
Solution Approach 1:
The feedback control system continuously monitors the actual mass of liquid dispensed and adjusts the pump operation duration in real-time. This eliminates the need to extend pump operation time as a compensatory measure for wear, as the system dynamically optimizes the cycle duration based on actual dispensing rate and target volume.
4Measurement precision
If additional sensors like flowmeters or optical sensors are added, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent replaces complex flow measurement systems (flowmeters, optical sensors) with a simple mass-based measurement system using a load cell. This mechanical substitution provides accurate measurement of dispensed volume through direct mass measurement, eliminating the need for complex flow sensing infrastructure.
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 ensures a consistent volume of liquid preparation is dispensed, reducing errors and maintaining pump protection by automatically adjusting the cycle time based on real-time mass measurements, eliminating the need for additional sensors like flowmeters or optical sensors.
Implementation Method 1
inserting a mass sensor under the liquid reservoir, and monitoring the mass dispensed
Implementation Method 2
at least one pump arranged to force said fluid, in the liquid and/or vapour state, to pass through at least one doser
Implementation Method 3
accounting for vaporisation losses
Implementation Method 4
either directly or via a boiler
Data Source
AI summary
A metering device for a machine for making a liquid preparation includes a liquid reservoir for storing a fluid and for feeding, via an inlet line, at least one pump arranged to force the fluid to pass, in the liquid and/or vapour state, through at least one doser including at least one ingredient, in order to make the preparation, and to dispense the preparation to an outlet line. The metering device also includes means for continuously measuring the mass of the reservoir and of its contents, and control means interfaced with the continuous measurement means and arranged to monitor the total mass as a function of time, and to instantaneously calculate the mass of the preparation already dispensed, to adapt the duration of operation of the pump to ensure that the exact quantity of preparation required is dispensed, and/or to trigger the shutdown of the pump if it is found to be running dry.