Valve Assembly for Tissue Sample Fixative Backflow Prevention
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Solution Overview
Problem
Existing sample collection systems that use fixative solutions, such as formalin, face challenges in preventing backflow when the container is inverted or tilted, compromising the integrity of the tissue sample and posing health risks due to the hazardous nature of these solutions.
Innovation Solution
A sample collection system with a valve assembly that allows fluid flow from a prefilled cap to a sample container when upright but prevents backflow when the system is inverted or tilted, using a mechanism with inherent resiliency or a resilient mechanism to automatically close the valve, ensuring the fixative solution remains with the sample regardless of orientation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a hermetically sealed container with two internal chambers is used to prevent backflow, then technician safety is improved, but the device cannot be stored or transported in any orientation
Solution Approach 1:
A one-way valve is introduced as an intermediary component between the cap and container chambers. This valve allows fluid to flow in only one direction (from cap to container) while blocking reverse flow, enabling the system to function safely in any orientation without requiring the container to be kept upright.
Solution Approach 2:
The system changes the flow parameters of the fixative solution by using a one-way valve that permits flow in one direction while preventing flow in the opposite direction. This parameter change (directional flow control) allows the container to be stored or transported in any orientation while maintaining sample immersion and preventing technician exposure.
2Device complexity
If gravity-dependent fluid exchange is used to submerge the specimen, then the system is simple, but the specimen may dry out if the container is not kept upright
Solution Approach 1:
A one-way valve serves as an intermediary that controls fluid exchange between chambers. It allows the fixative to flow from the cap to the container chamber to submerge the specimen, but prevents backflow that would cause the specimen to dry out, regardless of container orientation.
Solution Approach 2:
The one-way valve automatically regulates fluid flow based on pressure differential and orientation, eliminating the need for active control mechanisms. The valve self-adjusts to maintain specimen immersion while preventing overfilling or drying out, improving reliability without adding complexity.
3Reliability
If an inversion protection cap is used to prevent backflow, then sample integrity is improved, but the valve mechanism adds complexity
Solution Approach 1:
The one-way valve is implemented as a simple, disposable component integrated into the cap or container. This inexpensive valve mechanism provides reliable sample integrity protection through its unidirectional flow control, and can be discarded with the sample container, eliminating the need for complex, reusable valve systems.
Solution Approach 2:
The one-way valve may be implemented using flexible membrane or thin film structures that passively respond to pressure differential. This flexible valve design maintains sample integrity by preventing backflow while adding minimal complexity to the overall 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 effectively maintains the fixative solution in contact with the sample even when the container is not in an upright position, enhancing sample integrity and reducing exposure risks to hazardous fumes, while allowing for safe handling and transport in any orientation.
Implementation Method 1
the valve is adapted to default to a closed position, such that an external force is required to hold the valve in an open configuration that permits fluid exchange between the cap and the container
Implementation Method 2
when the valve is in the open configuration, one or more channel(s) is formed between the first and second chamber permitting fixative solution to flow from the first chamber to the second chamber
Data Source
AI summary
A method and system for processing a sample in a fluid is provided. An assembly comprising a cap prefilled with a fixative solution, a valve, and a container for storing a tissue sample are provided. The valve is adapted to be situated between the cap and the container such that fluid can flow from the cap into the container when the assembly is upright, but the fluid cannot backflow from the container to the cap when the assembly is horizontal or inverted.