Membrane Pumping Cassette for Equal-Volume Fluid Balancing
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Solution Overview
Problem
Existing fluid pumping systems face challenges in efficiently balancing and managing the flow of multiple fluids, particularly in applications requiring precise volume control and fluid mixing, such as hemodialysis systems, where the flow of pure and impure dialysate needs to be equalized.
Innovation Solution
A cassette design incorporating balancing pods with membranes forming chambers, reciprocating pressure displacement membrane pumps, and metering pumps to ensure equal fluid volumes, along with pneumatically actuated valves for precise fluid control and management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If reciprocating pressure displacement membrane pumps are used to balance fluid flow, then fluid volume balancing is improved, but device complexity increases due to multiple pumps and balancing chambers
Solution Approach 1:
The patent combines multiple pumps and balancing chambers into an integrated cassette assembly where components share common housing and fluid pathways. The first and second pumps are mounted within the same housing structure, and the balancing chambers are integrated into the overall assembly, reducing the number of separate components and simplifying the system architecture while maintaining precise fluid volume balancing capability.
2Measurement precision
If multiple balancing chambers and membranes are implemented, then fluid flow control precision is improved, but device complexity increases
Solution Approach 1:
The balancing chambers serve multiple functions within the system: they balance fluid volumes between different pump circuits, act as expansion chambers, and provide pressure equalization. The membranes in these chambers not only separate fluid pathways but also respond to pressure differentials to automatically regulate flow distribution. This multi-functionality reduces the need for additional dedicated components for each function.
3Manufacturing precision
If precise fluid volume equalization is achieved through balancing pods, then fluid management accuracy is improved, but ease of operation decreases due to complex pneumatic actuation systems
Solution Approach 1:
The balancing chambers with membranes are designed to automatically respond to pressure differentials between fluid pathways. When volume imbalances occur, the pressure differential causes the membranes to deflect, automatically opening or closing fluid pathways to restore balance without requiring external control signals. This self-regulating mechanism eliminates the need for complex electronic sensors and control algorithms.
4Productivity
If integrated cassette design with multiple components is used, then fluid handling efficiency is improved, but ease of manufacture decreases
Solution Approach 1:
The cassette is designed as a modular assembly with distinct functional modules: pump modules, balancing chamber modules, and valve modules. Each module can be manufactured and tested independently before final assembly. The housing is divided into sections that can be separately machined or molded, and components like membranes and seals can be pre-installed on sub-assemblies. This segmented approach maintains the efficiency benefits of integration while simplifying the manufacturing and quality control processes.
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 cassette effectively balances and manages the flow of fluids, ensuring equal volumes and precise fluid delivery, enhancing the efficiency and accuracy of fluid handling in applications like hemodialysis.
Implementation Method 1
at least one reciprocating pressure displacement membrane pump within the housing. The pumps are within the housing and they pump the fluid from a fluid inlet to a fluid outlet line and pump the second fluid from a fluid inlet to a fluid outlet
Implementation Method 2
at least one reciprocating pressure displacement membrane pump within the housing. The pumps are within the housing and they pump the fluid from a fluid inlet to a fluid outlet line
Implementation Method 3
Where the reciprocating pressure displacement pumps includes a curved rigid chamber wall and a flexible membrane attached to the rigid chamber wall. The flexible membrane and the rigid chamber wall define a pumping chamber
Data Source
AI summary
A pumping cassette including a housing having at least two inlet fluid lines and at least two outlet fluid lines. At least one balancing pod within the housing and in fluid connection with the fluid paths. The balancing pod balances the flow of a first fluid and the flow of a second fluid such that the volume of the first fluid equals the volume of the second fluid. The balancing pod also includes a membrane that forms two balancing chambers. Also included in the cassette is at least two reciprocating pressure displacement membrane pumps. The pumps are within the housing and they pump the fluid from a fluid inlet to a fluid outlet line and pump the second fluid from a fluid inlet to a fluid outlet.