Sterile Seal Assembly with Abradable Hermetic Barrier
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Solution Overview
Problem
Existing seal assemblies for maintaining a sterile environment in bio-reactors are inconvenient and prone to contamination due to the need for frequent replacement and inability to maintain sterility during multiple agitations and transport of sterile contents.
Innovation Solution
A seal assembly with a seal carrier that can move between a sealing and rotation position, featuring a hermetic seal that abrades away during rotation, allowing for multiple agitations while maintaining sterility and incorporating a purging gas system to maintain positive pressure and prevent contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a hermetic seal is pressed against a rotating element to maintain sterility during agitation, then sterility is maintained, but the hermetic seal abrades away and must be replaced frequently
Solution Approach 1:
The sealing system is divided into two distinct segments: a hermetic seal for maintaining sterility during rotation and a reusable seal carrier with replaceable seals. This segmentation allows the hermetic seal to be optimized for sterility while the seal carrier handles the mechanical wear, enabling frequent replacement of only the seal carrier assembly rather than the entire sealing system.
Solution Approach 2:
The seal carrier acts as an intermediary component between the hermetic seal and the rotating shaft. It carries the seals that contact the rotating element, protecting the hermetic seal from direct mechanical wear while still maintaining the sterile barrier. The seal carrier absorbs the mechanical stress and can be replaced without affecting the hermetic seal.
2Reliability
If the seal carrier moves between sealing and rotation positions, then the seal can maintain sterility during agitation, but the device complexity increases
Solution Approach 1:
The seal carrier is designed to be movable rather than fixed, allowing it to dynamically transition between a sealing position (where seals contact the stationary shaft portion) and a rotation position (where the shaft rotates without seal contact). This dynamic positioning enables sterility maintenance during agitation while simplifying the overall structure by allowing the shaft to rotate freely when not agitating.
Solution Approach 2:
The seal carrier periodically transitions between sealing and rotation positions corresponding to the agitation cycles. During agitation, the seal carrier moves to the rotation position to allow shaft movement; during non-agitation periods, it returns to the sealing position to maintain sterility. This periodic action aligns the sealing mechanism with the operational cycles of the bioreactor.
3Reliability
If pass-throughs are replaced after each agitation to maintain sterility, then contamination risk is reduced, but manufacturing convenience and time are reduced
Solution Approach 1:
The seal carrier is designed as a disposable or easily replaceable component that can be quickly changed between agitation cycles. Rather than replacing expensive or complex pass-through assemblies, the seal carrier serves as a low-cost, short-service-life component that maintains sterility for one agitation cycle and is then replaced, significantly reducing manufacturing time and complexity.
Solution Approach 2:
The seal carrier is discarded or replaced after each agitation cycle rather than being cleaned and reused. This approach eliminates the need for complex cleaning and sterilization procedures between cycles, as the entire seal carrier assembly can be quickly replaced with a pre-sterilized unit, improving manufacturing efficiency while maintaining sterility.
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 seal assembly effectively maintains sterility during multiple agitations and transport of sterile contents, reducing contamination risks and the need for frequent replacements, while allowing for continuous use without compromising the sterile environment.
Implementation Method 1
a hermetic seal configured to be abraded away by a rotating element that the hermetic seal is pressing against
Implementation Method 2
a hermetic seal configured to be abraded away by a rotating element that the hermetic seal is pressing against
Data Source
AI summary
A seal assembly includes a seal body having a space formed therein; a seal carrier held within the space, the seal carrier being selectively positionable between a sealing position and a rotation position by moving along a carrying path; at least one seal carried by the seal carrier; and a hermetic seal held within the space out of the carrying path of the seal carrier, the hermetic seal being configured to be abraded away by a rotating element that the hermetic seal is pressing against.