Peristaltic Pump Dosing with Weighing Verification

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Solution Overview

Problem

Existing systems for producing parenteral nutrition preparations face challenges in accurately dosing both large and micro-amount components due to the non-linear characteristic curve of peristaltic pumps, which affects the precision of liquid transfer and increases the risk of dosing errors, especially when handling components like water, fat, sugar, amino acids, vitamins, and medications.

Innovation Solution

The method employs a peristaltic pump with a transfer set and a valve unit to manage the precise dosing of components by using the suction-side and pressure-side characteristic curves for accurate volume calculation and weighing, ensuring that each dosing step is checked and validated, and the system is calibrated to account for the non-linear pump performance, particularly in the linear range for micro-amounts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a peristaltic pump is used to transfer liquids from source containers to a target container, then the dosing process can be automated and performed continuously, but the non-linear characteristic curve of the pump reduces dosing precision, especially for micro-amount components

Engineering Contradiction:
Improveautomation of dosing processVSAvoiddosing precision
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The system dynamically adjusts pump parameters (rotation speed, dosing volume) based on the specific component being transferred. By changing operational parameters according to the component type and required dosage, the system compensates for the non-linear pump characteristics and achieves precise dosing across different volumes, from large main constituents to micro-amount additives.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system incorporates feedback mechanisms where the actual dosing performance is continuously monitored and compared against target values. Based on this feedback, the control system adjusts pump parameters in real-time to maintain dosing precision, effectively compensating for the non-linear characteristic curve and ensuring accurate delivery of both large and micro-amount components.

Inventive Principle:
Principle #23Feedback

2Productivity

If the peristaltic pump operates in the non-linear region of its characteristic curve, then larger volumes can be transferred more quickly, but dosing accuracy deteriorates for micro-amount components

Engineering Contradiction:
Improvetransfer speedVSAvoiddosing accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The system selectively changes operational parameters based on the dosage requirements. For micro-amount components, the pump operates in the linear region with reduced rotation speed and smaller dosing volumes to maximize precision. For main constituents requiring larger volumes, the system adjusts parameters to operate more efficiently while still maintaining acceptable accuracy through compensation algorithms.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The dosing process is segmented into different operational phases corresponding to different component types. Main constituents are dosed in one phase with parameters optimized for volume transfer, while micro-amount components receive dedicated dosing phases with parameters optimized for precision. This segmentation allows the system to prioritize accuracy when needed without sacrificing overall productivity.

Inventive Principle:
Principle #1Segmentation

3Adaptability or versatility

If multiple components are dosed in sequence from different source containers, then complete medical preparations can be manufactured, but the complexity of managing dosing sequences and verifying each step increases

Engineering Contradiction:
Improveability to manufacture complete preparationsVSAvoidprocess control complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The system employs a universal control architecture and standardized interface for dosing all component types. The same peristaltic pump, control system, and verification procedures are used regardless of whether dosing main constituents or micro-amount additives, simplifying the overall process management despite the diversity of components and sequences required.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system incorporates automatic verification and documentation of each dosing step. The control system automatically tracks which components have been dosed, verifies dosing accuracy, and maintains records without requiring manual intervention. This self-verification capability reduces the operational complexity of managing multi-component sequences while ensuring completeness and accuracy.

Inventive Principle:
Principle #25Self-service

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 approach enhances the accuracy and reliability of the dosing process, ensuring that the medicinal preparation meets specifications by precisely measuring and verifying each dosing step, reducing the likelihood of errors and ensuring the safety and efficacy of the final product.

Implementation Method 1

The peristaltic pump is a positive displacement pump in which the fluid to be pumped is forced through the hose by external mechanical deformation. For this purpose, the peristaltic pump preferably has an impeller with rollers that compress the hose.

Methodology Applied
Scientific EffectPeristalsis: Peristalsis

Data Source

PatentEP4218709A1Method for preparing a medical preparation
Publication Date: 2023.08.02 FRESENIUS KABI DEUTSCHLAND GMBH
  • EP4218709A1 patent drawingFigure 1
  • EP4218709A1 patent drawingFigure 2
  • EP4218709A1 patent drawingFigure 3

AI summary

The invention relates to a method and a system for producing a medical preparation, wherein a peristaltic pump is used to draw liquid from a plurality of source containers. According to the invention, the individual dosing steps are verified by weighing, whereby the verification of the dosing of micro-quantities is also possible.