Inline Buffer Dilution With Backpressure-Controlled Mixing
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Solution Overview
Problem
Existing inline buffer dilution systems face challenges in maintaining consistent mixing quality across varying fluid flows, particularly in ensuring adequate mixing at different flow rates, which limits their scalability and efficiency in producing solutions with desired characteristics like pH, conductivity, and refractive index.
Innovation Solution
The inline buffer dilution system employs a scalable design with proportional pinch valves, a programmable logic controller, and a mixing pump with adjustable backpressure, ensuring consistent mixing across a range of fluid flows by controlling the flow of diluent and buffer liquids and using sensors for real-time feedback to maintain desired solution characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If external pressurization is used to maintain buffer flow, then fluid flow is improved, but device complexity and cost increase
Solution Approach 1:
The system uses the peristaltic pump's inherent pumping action to create negative pressure that draws buffer solution through the mixing chamber, eliminating the need for external pressurization devices. The pump itself provides both the driving force for fluid flow and the mixing action through its rotating rollers compressing the tubing.
Solution Approach 2:
The patent removes the external pressurization system from the overall design, using only the pump's internal mechanisms to achieve both fluid delivery and mixing functions. This extraction of unnecessary components simplifies the device while maintaining functionality.
2Manufacturing precision
If mixing chamber volume is increased to improve mixing quality, then mixing effectiveness is improved, but device size and fluid residence time increase
Solution Approach 1:
The peristaltic pump creates pulsating flow and mechanical compression of the tubing as it rotates, generating turbulent mixing effects within a compact chamber. The periodic compression and release of tubing by the pump rollers creates shear forces that enhance mixing without requiring a large chamber volume.
Solution Approach 2:
The system uses fluid dynamics and pressure variations created by the peristaltic pumping action to achieve effective mixing. The alternating compression and decompression of the fluid stream within the narrow chamber creates sufficient turbulence for thorough mixing of buffer solutions.
3Productivity
If flow rate is increased to improve productivity, then output is improved, but mixing quality deteriorates
Solution Approach 1:
The peristaltic pump provides dynamic mixing through its rotating motion, where the speed and pattern of roller compression can be adjusted to maintain effective mixing across a range of flow rates. The system adapts the mixing mechanism to the flow conditions, allowing high productivity while preserving mixing quality.
Solution Approach 2:
The buffer solutions are pre-mixed in their respective reservoirs before entering the mixing chamber, ensuring homogeneous input streams. This preliminary preparation allows the compact mixing chamber to achieve final blending efficiency even at higher flow rates.
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 configuration ensures a minimum mixing threshold across a range of fluid flows from 2 to 20 liters per minute, allowing for the production of solutions with precise characteristics, such as pH and conductivity, while reducing the need for external pressurization of buffer solutions and enabling the use of disposable containers.
Implementation Method 1
a peristaltic mixing pump downstream of the flow control valves
Implementation Method 2
a conductivity sensor and a pH sensor downstream of the mixing pump
Implementation Method 3
a conductivity sensor and a pH sensor downstream of the mixing pump
Data Source
Figure 1
Figure 2~3
AI summary
An inline buffer dilution system is provided that includes a first flow control valve fluidly connected to a supply of diluent liquid, second and third flow control valves fluidly connected to supplies of a first buffer and a second buffer, respectively, and a mixing pump fluidly connected to the first, second, and third flow control valves and configured to mix an amount of the diluent liquid, the first buffer, and the second buffer to produce a diluted buffer solution. The system further includes a backpressure control valve configured to generate a backpressure that promotes mixing within the mixing pump, and a controller configured to control the backpressure based on the amount of the diluent liquid, the first buffer, and the second buffer being mixed in the mixing pump, such that the mixing pump yields a minimum mixing threshold across a range of fluid flows.