Ultrasound Bubble Sensor for Liquid Filling Dosing Accuracy

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Solution Overview

Problem

Existing filling machines face challenges in achieving precise and reliable weight measurement of small doses of pharmaceutical, cosmetic, and food liquid products in containers, particularly due to interference from vibrations, accelerations, and air turbulences, which affects the accuracy and productivity of the filling process.

Innovation Solution

The implementation of a bubble sensor using ultrasound technology to detect and measure gas bubbles in the product flow, allowing for precise calculation of the effective volume and weight of the product, independent of environmental interferences, and integration with a weighing system to regulate the dosing unit and prevent out-of-spec containers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If electronic scales are used to measure the weight of filled containers, then the weight can be measured, but the measuring time is insufficient for high-speed filling, leading to inadequate stabilization of the load cell

Engineering Contradiction:
Improvefilling speedVSAvoidweight measurement precision
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent applies preliminary action by measuring the weight of empty containers (tare weight) before the filling process. This allows the system to have advance knowledge of the container weight, so that during high-speed filling operations, only the net weight of the product needs to be determined, reducing the required measurement time and allowing faster operation while maintaining accuracy.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements partial weighing by measuring only the net weight of the product in the container rather than the total weight. The system uses the pre-stored tare weight and subtracts it from the gross weight measurement to obtain the net product weight. This partial measurement approach reduces the measurement time requirement while maintaining sufficient precision for quality control.

Inventive Principle:
Principle #16Partial or excessive action

2Measurement precision

If the measuring time is extended to allow load cell stabilization, then measurement precision improves, but productivity decreases

Engineering Contradiction:
Improveweight measurement precisionVSAvoidfilling speed
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The system performs preliminary measurement of the empty container weight before filling. This tare weight is stored and reused during production, eliminating the need to measure container weight during each high-speed filling cycle. This allows extended measurement time for product weight only when needed, while maintaining high overall productivity.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements dynamic measurement strategy where the system adapts its measurement approach based on operational requirements. During high-speed filling, the system uses rapid net weight measurement with pre-stored tare values. When calibration or verification is needed, the system can perform more precise measurements with longer stabilization time, optimizing the balance between speed and precision dynamically.

Inventive Principle:
Principle #15Dynamics

3Measurement precision

If tare weight is subtracted from gross weight to calculate net weight, then product weight can be determined, but container weight variations affect measurement accuracy for small doses

Engineering Contradiction:
Improvenet weight calculation accuracyVSAvoidsmall dose quantity
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The system performs preliminary measurement and storage of the tare weight for each container before filling. By having the container weight known in advance, the system can focus measurement resources on accurately measuring only the product weight, improving the signal-to-noise ratio for small dose measurements and reducing the impact of container weight variations.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent replaces the traditional approach of measuring only the final filled container weight with a two-stage measurement system. The first stage measures empty container weight, and the second stage measures the filled container. This substitution of the measurement methodology allows for better handling of small dose quantities by separating the container and product measurements, reducing error propagation.

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 enables precise and reliable weight checking of all containers, minimizes the number of rejected containers, and maintains high productivity by accurately detecting and correcting for gas bubbles, ensuring precise dosing without being influenced by machine-related perturbations.

Implementation Method 1

The implementation of a bubble sensor using ultrasound technology to detect and measure gas bubbles in the product flow

Methodology Applied
Scientific EffectUltrasound: Ultrasound

Data Source

PatentEP3416892B1Dosing method and filling machine
Publication Date: 2023.08.23 IMA IND MASCH AUTOMATICHE SPA

AI summary

A method for dosing a product in liquid form in containers (100) comprising transferring doses of product (20) by means of a dosing unit (2) from a feed tank (3) in the containers (100), each dose comprising a pre-established quantity of product; during said transferring, controlling through a bubble sensor (10) the doses of product (20) which flow out from the feed tank (3) through the dosing unit (2) up to the containers (100) to detect the presence of gas bubbles (21) and measure a volume of the gas bubbles (21) in each dose of product (20); delivering the doses of product (20) inside the containers (100); measuring in a weighing station (16) through a weight sensor (22) a weight of the doses of product (20) dosed in said containers (100); arranging a processing and control unit (30) set up to receive and process a weight signal of the weight sensor (22) and a bubbles signal (21) from the bubble sensor (10), said processing and control unit (30) being connected to the dosing unit (2) in order to modify the pre-established quantity of product supplied for each dose of product (20) as a function of the weight signal received by the weight sensor (22); the processing and control unit (30) is further set up to inhibit to modify the pre-established quantity of product supplied for each product dose (20) as a function of the weight signalreceived by the weight sensor (22), in case the bubble sensor (20) detects a volume of gas bubbles (21) in the doses of product (20) that is lower than a predefined reference value.