Aseptic Mixing Bar Pivoting Through Narrow Container Necks

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Solution Overview

Problem

Conventional mixing systems for biotech and pharmaceutical processing face challenges such as bacterial ingress, contamination from friction and particle shedding, and difficulty in inserting large stir bars due to container neck size limitations, which compromise the aseptic environment and mixing efficiency.

Innovation Solution

An aseptic mixing system with a mixer that includes a cap, extension shaft, and a mixing bar with a lock sleeve, allowing the mixing bar to pivot from a parallel to perpendicular position within the container, forming a seal and maintaining an aseptic environment, using inert plastics and neodymium magnets to minimize contamination and facilitate insertion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a large stir bar is used for effective mixing, then mixing efficiency is improved, but it cannot be inserted through the narrow container opening

Engineering Contradiction:

Improvemixing efficiencyVSAvoidinsertion difficulty

Core Design Contradiction:

ProductivityVSEase of operation

Solution Approach 1:

The mixing bar is designed to change its orientation dynamically. During insertion, it is positioned parallel to the longitudinal axis to fit through the narrow opening. Once inside the container, it pivots 90 degrees to become perpendicular to the longitudinal axis, where it can effectively mix the contents. This dynamic repositioning resolves the contradiction between size needed for mixing and size constraint for insertion.

Inventive Principle:

Principle #15Dynamics

2Productivity

If the stir bar contacts the container interior during rotation, then mechanical stirring is achieved, but particle shedding and contamination occur

Engineering Contradiction:

Improvestirring functionVSAvoidparticle shedding

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent replaces direct mechanical contact between the stir bar and container walls with magnetic field interaction. An external magnet positioned below the container drives the magnetic stir bar to rotate without physical contact. This eliminates friction, particle shedding from the stir bar, and contamination from container wall contact, while still achieving effective stirring through magnetic coupling.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Ease of repair

If the container is opened for mixing operations, then access for maintenance and cleaning is improved, but bacterial ingress and contamination risk increase

Engineering Contradiction:

Improvecleaning accessibilityVSAvoidbacterial ingress

Core Design Contradiction:

Ease of repairVSObject-affected harmful factors

Solution Approach 1:

The magnetic drive system allows the container to remain completely sealed during mixing operations. The external magnet transmits rotational force through the container wall via magnetic field, eliminating the need for openings or shafts that would compromise the sterile seal. This maintains aseptic conditions while enabling mixing functionality.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Force

If friction occurs between the stir bar and container interior, then rotational drive is achieved, but debris is generated during irradiation

Engineering Contradiction:

Improverotational driveVSAvoiddebris generation

Core Design Contradiction:

ForceVSObject-generated harmful factors

Solution Approach 1:

The patent eliminates mechanical friction between the stir bar and container by using magnetic field coupling. The external magnet rotates the magnetic stir bar through the container wall without physical contact, preventing wear, debris generation, and contamination that would occur with friction-based drive mechanisms, especially during irradiation processes.

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

The system ensures effective mixing without contact with the container interior, reduces particle shedding, and maintains an aseptic environment by preventing contamination, while allowing large stir bars to be used despite narrow container openings.

Implementation Method 1

The rod shaped internal magnet may be engaged by an external magnet located below the container and driven to rotate around an axis perpendicular to a longitudinal axis

Methodology Applied

Scientific EffectMagnetic field: Magnetic Field

Implementation Method 2

the inert plastic and an upper hinge portion is secured to the second end via a bearing

Methodology Applied

Scientific EffectRadiation resistance: Radiation

Data Source

PatentEP3804845B1Aseptic mixing system and method for sealing an aseptic container

Publication Date: 2025.11.19 SANISURE INC

Figure 1A~1B
Figure 2A~2G
Figure 3

AI summary

An aseptic mixing system is provided adapted to couple to and seal an aseptic container which when upright has an upper mouth having external threads and defining an opening into the container with a diameter leading to a wider bottom mixing portion, the system being characterized in that: a mixer having a cap (12), an extension shaft (10) having a first end connected to an underside of the cap (12) and extending along a longitudinal axis (Z) to a second end, a mixing bar (8) connected and rotatable about two axes with respect to the second end of the extension shaft (10), and a lock sleeve (9) axially slidable along the extension shaft (10), the cap (12) includes internal threads configured to engage the external threads of the container upper mouth, the cap and upper mouth being configured to form an aseptic seal and maintain an aseptic environment within the container.