Fermentation Vessel Hydrodynamic Seal for Oxygen Transfer

Solution Overview

Problem

Conventional fermentation apparatuses face challenges in maintaining efficient oxygen transfer during submerged fermentation due to bubble coagulation, which can be mitigated by anticoagulation chemicals or high-speed stirring, but these solutions either affect product quality or incur high energy costs.

Innovation Solution

A low-speed stirrer system with a hydrodynamic seal assembly that introduces processing gas through a shaft with rotating sealing rings, creating small bubbles and enhancing gas/liquid interface at low speeds, suitable for small-scale fermentation vessels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If high-speed stirring is used to break up coagulated bubbles, then oxygen transfer efficiency is improved, but energy consumption increases and cell cultures may be damaged

Engineering Contradiction:

Improveoxygen transfer efficiencyVSAvoidenergy consumption

Core Design Contradiction:

ProductivityVSUse of energy by moving object

Solution Approach 1:

The aeration system is segmented into multiple levels with separate aeration rings at different heights in the vessel. Each ring creates bubbles at a specific location, distributing the aeration function across multiple segments rather than relying on a single high-speed stirrer. This segmentation allows effective oxygen transfer without the need for high-speed mixing throughout the entire vessel.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A stationary screen or mesh structure is introduced as an intermediary element between the gas source and the liquid medium. This screen breaks up large bubbles into smaller bubbles passively as gas passes through it, eliminating the need for mechanical high-speed stirring. The screen acts as a mediator that achieves bubble breakup without direct mechanical intervention.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If high-speed stirring is used to break up coagulated bubbles, then oxygen transfer efficiency is improved, but cell culture integrity deteriorates

Engineering Contradiction:

Improveoxygen transfer efficiencyVSAvoidcell culture damage

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The aeration system is segmented into multiple levels with separate aeration rings at different heights in the vessel. Each ring creates bubbles at a specific location, distributing the aeration function across multiple segments rather than relying on a single high-speed stirrer. This segmentation allows effective oxygen transfer without the need for high-speed mixing throughout the entire vessel.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A stationary screen or mesh structure is introduced as an intermediary element between the gas source and the liquid medium. This screen breaks up large bubbles into smaller bubbles passively as gas passes through it, eliminating the need for mechanical high-speed stirring. The screen acts as a mediator that achieves bubble breakup without direct mechanical intervention.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Productivity

If anticoagulation chemicals are used to prevent bubble coagulation, then oxygen transfer efficiency is improved, but product quality deteriorates

Engineering Contradiction:

Improveoxygen transfer efficiencyVSAvoidproduct quality contamination

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

A stationary screen or mesh structure is introduced as an intermediary element between the gas source and the liquid medium. This screen breaks up large bubbles into smaller bubbles passively as gas passes through it, eliminating the need for chemical anticoagulants. The screen acts as a physical mediator that achieves bubble breakup without introducing harmful chemicals into the fermentation process.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces chemical methods (anticoagulation chemicals) with a physical method (stationary screen or mesh structure) to achieve the same effect of preventing bubble coagulation. This substitution eliminates chemical contamination risks while maintaining oxygen transfer efficiency.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Productivity

If rapid stirring is used to prevent bubble coagulation, then oxygen transfer efficiency is improved, but cooling requirements increase

Engineering Contradiction:

Improveoxygen transfer efficiencyVSAvoidoperating temperature control

Core Design Contradiction:

ProductivityVSTemperature

Solution Approach 1:

The aeration system is segmented into multiple levels with separate aeration rings at different heights in the vessel. Each ring creates bubbles at a specific location, distributing the aeration function across multiple segments rather than relying on a single high-speed stirrer. This segmentation allows effective oxygen transfer without the need for high-speed mixing throughout the entire vessel, thereby reducing heat generation.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A stationary screen or mesh structure is introduced as an intermediary element between the gas source and the liquid medium. This screen breaks up large bubbles into smaller bubbles passively as gas passes through it, eliminating the need for mechanical high-speed stirring. The screen acts as a mediator that achieves bubble breakup without direct mechanical intervention, avoiding the heat generation associated with rapid stirring.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 increases oxygen transfer rates at low energy costs without contaminating the product, maintaining optimal operating temperatures and being cost-effective for small-scale operations.

Implementation Method 1

resiliently biased towards one another, so that a sealing face of the first sealing ring may be biased into engagement with a sealing face of the second sealing ring

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 2

the grooves, which will provide hydrodynamic separation of the sealing faces upon rotation of the shaft, allowing processing gas in the chamber to flow inwardly across the sealing faces

Methodology Applied

Scientific EffectHydrodynamic separation:

Implementation Method 3

the dam formation on the one sealing face will sealingly engage the other sealing face

Methodology Applied

Scientific EffectFluid tight seal:

Data Source

PatentEP1974007B1Fermentation vessels

Publication Date: 2009.11.11 JOHN CRANK UK

Figure 1
Figure 2~4

AI summary

A fermentation apparatus (10) with a fermentation vessel (12) having a low speed stirrer, the stirrer comprising a shaft (14) entering the vessel through an aperture (16) in the bottom of the vessel, one or more stirring elements (18) being mounted on the shaft for rotation therewith within the vessel; a seal (20) being provided to seal the gap between the shaft and aperture, the seal being located in a cylindrical housing attached to the bottom of the vessel, the seal having first and second seal assemblies (30, 50) spaced axially of one another to define a chamber (64) therebetween, an inlet (66) opening into said chamber for connection of the chamber to a supply of processing gas, the first seal assembly (30) being located between the fermentation vessel and the chamber comprising a seat (32) mounted on the shaft for rotation therewith and a mating ring mounted (36) in fixed rotational relationship but moveably axially of the housing, a sealing face (44) of the mating ring being resiliently biased into engagement with a sealing face (42) of the seat, the sealing face of one of the mating ring or the seat having grooves (68) , which will provide hydrodynamic separation of the sealing faces upon rotation of the shaft .