Zero-Dead-Leg Valve Structure for Sterile Fluid Mixing
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Solution Overview
Problem
Current bioreactor and mixer systems face inefficiencies in mixing biological fluids due to dead-leg regions, incomplete distribution of processing aids, and shear stress issues, leading to inaccurate samples and waste of valuable reagents.
Innovation Solution
A fluid transfer device with a valve design featuring an extended flange and a longitudinally displaceable plunger, which creates a zero dead-leg condition, ensuring consistent concentrations and efficient mixing by eliminating stagnant areas and reducing shear stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If ports are located at the bottom or sidewall of the container with attached tubes, then materials can be supplied to the system, but dead-leg regions form causing incomplete distribution and waste of reagents
Solution Approach 1:
The valve body is inverted relative to conventional designs, with the closure member positioned at the top rather than the bottom. This inversion eliminates dead-leg regions where reagents would otherwise accumulate, ensuring complete distribution of materials throughout the container without waste.
Solution Approach 2:
The closure member is extracted from the traditional port location and repositioned to create a valve structure that eliminates stagnant zones. The valve body and closure member are designed to work together to remove dead-leg regions entirely from the system.
2Productivity
If mixing speeds are increased to prevent settling of processing aids, then mixing efficiency improves, but shear stress increases damaging cells
Solution Approach 1:
The valve design changes the flow parameters by eliminating dead-leg regions, allowing materials to be introduced at optimal concentrations directly into the mixing zone. This enables effective mixing at lower speeds, reducing shear stress on cells while maintaining mixing efficiency.
3Measurement precision
If dip tubes are used to take samples from containers, then samples can be obtained, but sterilization is required and contamination risk increases
Solution Approach 1:
The valve serves multiple functions: it controls material introduction, eliminates dead-leg regions for complete distribution, and provides a sterile barrier for sampling. The same valve structure that prevents reagent waste also enables contamination-free sampling by maintaining the sterile seal.
4Loss of time
If single use sterilized containers are employed to reduce sterilization time, then manufacturing flexibility increases, but dead-leg regions still form causing incomplete material distribution
Solution Approach 1:
The valve is designed with an inverted orientation where the closure member is positioned to eliminate dead-leg regions in single-use containers. This design ensures that even in disposable containers, materials are distributed completely without stagnant zones, maintaining productivity despite the single-use nature of the container.
Data Source
AI summary
A valve having a body having a first section and a second section; an extended flange attached to the second section of the body or disposed as an integral part of the second section of the body; an elongate bore extending through the body and having a proximal end and a distal end; a longitudinally displaceable plunger disposed in and extending along the bore, the plunger having a proximal end and a distal end and having a first position displaced toward the distal end of the bore and a second position displaced toward the proximal end of the bore; a diaphragm seal attached to the proximal end of the plunger and sealing the bore at the proximal end thereof; a gland seal sealing the bore at a location intermediate the diaphragm seal and the distal end of the bore; the plunger extending through and being sealingly secured to the gland seal; a fluid transfer opening in the bore between the diaphragm seal and the gland seal; longitudinal displacement of the plunger moving the diaphragm seal to open the bore, the gland seal stretching to accommodate the displacement of and maintain a seal about the plunger, a fluid flow path being established between the open proximal end of the bore and the fluid transfer opening, wherein longitudinal displacement of the plunger towards its first position moves the diaphragm to open the bore. The valve further comprises an extended flange having a surface that is approximately coplanar with a surface of the second position when the plunger is displaced toward the proximal end of the bore, creating a zero dead leg position.