Trochoidal Pump Rotor Material and Geometry for Accurate Medicament Dosing

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Solution Overview

Problem

Existing trochoidal medicament delivery devices lack improved delivery properties, accuracy, reliability, and longevity.

Innovation Solution

A trochoidal medicament pump device with a pump rotor having a triangular convex shape and an eccentric trajectory, featuring a rigid rotor core and an elastomeric over-mold, which forms suction and expelling volumes through a trochoidal-shaped pump chamber with a pressure compensation bypass, ensuring reliable sealing and efficient fluid delivery.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a trochoidal pump device is used for medicament delivery, then pumping function is achieved, but delivery accuracy and reliability are insufficient

Engineering Contradiction:
Improvedelivery accuracyVSAvoiddelivery reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The pump rotor employs an elastomeric over-mold that forms flexible sealing surfaces against the pump chamber walls. This elastic material deforms to maintain continuous sealing contact during rotation, preventing medicament leakage and ensuring accurate delivery volumes while maintaining reliable operation.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The pump rotor is constructed as a composite structure with a rigid core providing structural stability and an elastomeric over-mold providing sealing functionality. This combination of materials optimizes both the mechanical strength needed for reliable operation and the sealing capability required for accurate medicament delivery.

Inventive Principle:
Principle #40Composite materials

2Measurement precision

If sealing is improved by increasing contact pressure, then delivery accuracy improves, but friction and wear increase reducing lifetime

Engineering Contradiction:
Improvedosage accuracyVSAvoiddevice lifetime
Core Design Contradiction:
Measurement precisionVSDuration of action of moving object

Solution Approach 1:

The elastomeric material properties are specifically selected and optimized to provide adequate sealing contact pressure under operating conditions while maintaining low friction coefficients. The material's viscoelastic properties allow it to conform to surface irregularities without excessive wear, extending device lifetime while ensuring accurate dosage delivery.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The flexible elastomeric over-mold naturally adapts to the pump chamber geometry, maintaining sealing contact without requiring high contact pressures. This reduces friction and wear on both the rotor and chamber surfaces, extending device lifetime while preserving dosage accuracy through consistent sealing.

Inventive Principle:
Principle #30Flexible shells and thin films

3Manufacturing precision

If a rigid rotor is used for precise geometry, then manufacturing precision is achieved, but sealing reliability deteriorates

Engineering Contradiction:
Improverotor geometry precisionVSAvoidsealing reliability
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The rotor combines a rigid core with precisely manufactured geometry to maintain dimensional stability and an elastomeric over-mold that provides compliant sealing surfaces. The rigid core ensures consistent rotor positioning and geometry, while the elastic outer layer adapts to the pump chamber, ensuring reliable sealing despite manufacturing tolerances.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

Different regions of the rotor have different material properties: the core provides rigid geometric precision where dimensional stability is critical, while the elastomeric over-mold provides compliant sealing surfaces where contact with the pump chamber is required. This local differentiation of material quality optimizes both manufacturing precision and sealing reliability.

Inventive Principle:
Principle #3Local quality

4Productivity

If pump chamber volume is increased for higher delivery capacity, then productivity improves, but sealing complexity increases reducing reliability

Engineering Contradiction:
Improvemedicament delivery capacityVSAvoidsealing reliability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The elastomeric over-mold on the rotor creates flexible sealing surfaces that adapt to larger pump chamber volumes without requiring additional sealing components or complex geometries. The elastic material maintains sealing effectiveness across varying chamber sizes, enabling higher delivery capacity while preserving sealing reliability.

Inventive Principle:
Principle #30Flexible shells and thin films

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

The device provides enhanced delivery accuracy, reliability, and extended lifetime by maintaining airtight seals and reducing variability in dosage, while minimizing external influences and impurities.

Implementation Method 1

The pump rotor has a rigid rotor core and an elastic or elastomeric over-mold over at least sealing lines along the apexes and sealing lines along the convex curved lines

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

a pump rotor having a triangular convex shape and having an eccentric trajectory upon rotation, i.e. revolving around an axis, within the pump body

Methodology Applied
Scientific EffectEccentric rotation: Eccentric

Implementation Method 3

the second inner wall portion has in a circumferential direction at least section-wise a notch formed therein forming upon rotation of the pump rotor a pressure compensation bypass between the second expelling volume and the second suction volume

Methodology Applied
Scientific EffectPressure compensation: Pressure Gradient

Data Source

PatentEP4438900B1Trochoidal medicament pump device: material and geometry
Publication Date: 2026.03.18 MEDICO INVEST AG
  • EP4438900B1 patent drawingFigure 1~4
  • EP4438900B1 patent drawingFigure 5~6
  • EP4438900B1 patent drawingFigure 7~8

AI summary

Trochoidal medicament pump device, and a giving set having included said trochoidal medicament pump device, which has a particular geometry and material selection. The trochoidal medicament pump device and the giving set having included said trochoidal medicament pump device provides a trochoidal medicament pump device and giving set having included said trochoidal medicament pump device with improved delivery properties, exactness, reliability, and lifetime.