Pulsatile Dialysis Fluid Pump for Compact Hemodialysis
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Solution Overview
Problem
Current blood purifying apparatuses are limited in increasing blood flow rate and filtration efficiency due to size constraints and weight considerations, which hampers the effectiveness of convective mass transfer in hemodialysis.
Innovation Solution
A fluid pumping device with multiple chambers and a chamber pressurizing member that alternately compresses and expands chamber spaces to enhance filtration and backfiltration cycles, regulating flow passages to fluctuate dialysis fluid pressure and improve mass transfer between blood and dialysis fluid.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If blood flow rate is increased to improve convective mass transfer efficiency, then dialysis efficiency is improved, but the size and weight of the blood purifying apparatus must be increased which is not feasible for portable use
Solution Approach 1:
The patent applies periodic action by implementing pulsatile dialysis fluid flow through alternating compression and expansion of chambers. The chamber pressurizing member periodically changes chamber volume to create pressure fluctuations in dialysis fluid, generating pulsatile flow that enhances convective mass transfer. This periodic action allows efficient dialysis without requiring continuously high blood flow rates, thereby avoiding increased apparatus size and weight.
Solution Approach 2:
The patent changes the pressure parameter of dialysis fluid by periodically varying chamber volume through the chamber pressurizing member. This parameter change creates pressure gradients that drive pulsatile flow and enhance mass transfer efficiency. By modifying pressure dynamics rather than increasing flow rate, the system achieves improved dialysis efficiency without proportionally increasing apparatus size and weight.
2Productivity
If blood flow rate is increased to enhance convective mass transfer, then waste removal efficiency is improved, but the apparatus size must be increased which compromises portability
Solution Approach 1:
The chamber pressurizing member periodically alternates between compression and expansion phases, creating pulsatile dialysis fluid flow. This periodic action enhances convective mass transfer and waste removal efficiency without requiring increased blood flow rates or larger apparatus volume. The pulsatile flow pattern maximizes mass transfer within the constrained apparatus size.
Solution Approach 2:
The system introduces dynamic pressure variations through the chamber pressurizing member that periodically changes chamber volume. This dynamic operation creates time-varying pressure gradients that enhance convective mass transfer efficiency, allowing effective waste removal within a compact apparatus volume without requiring continuously high flow rates.
3Productivity
If multiple chambers with chamber pressurizing members are added to create pulsatile flow, then mass transfer is enhanced, but device complexity increases
Solution Approach 1:
The patent merges multiple chambers into a single integrated pumping device where the chamber pressurizing member simultaneously or sequentially actuates multiple chambers. This combining approach creates pulsatile flow and enhances mass transfer efficiency while avoiding the complexity of multiple independent pumping systems. The unified structure reduces overall device complexity compared to using separate pumps for each chamber.
Solution Approach 2:
The chamber pressurizing member serves multiple functions: it compresses and expands multiple chambers, generates pulsatile dialysis fluid flow, creates pressure gradients for enhanced mass transfer, and maintains fluid circulation. This multi-functional component achieves mass transfer enhancement without proportionally increasing device complexity, as one component performs several critical functions simultaneously.
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 solution enhances the total volume of filtration during blood purification, improving efficiency without increasing the size of the blood purifying filter or flow rates, and allows for miniaturization of the apparatus, making it suitable for home or portable hemodialysis.
Implementation Method 1
a chamber pressurizing member which compresses or expands the internal spaces of the chambers so as to allow a fluid to flow through the chambers
Implementation Method 2
taking advantages of diffusion applied due to the concentration difference and filtration applied due to the pressure difference between blood and dialysis fluid
Implementation Method 3
filtration applied due to the pressure difference between blood and dialysis fluid
Implementation Method 4
a convective mass transfer, because blood purifying filters in typical blood purifying apparatuses are limited in size and blood flow rate is restrictively allowed to be increased
Data Source
AI summary
Provided is a blood purifying apparatus including a blood purifying filter in which mass transfer occurs between blood and dialysis fluid, a blood tube connecting the blood purifying filter and a patient to allow blood to flow therethrough, a dialysis fluid supply tube connected to the blood purifying filter and allowing dialysis fluid to be supplied to the blood purifying filter therethrough, a dialysis fluid discharge tube connected to the blood purifying filter and allowing dialysis fluid to be discharged from the blood purifying filter therethrough; and a fluid pumping device. The fluid pumping device further includes a plurality of chamber each having an internal space, a chamber pressurizing member disposed inside the plurality of chambers and compressing or expanding the chambers to thereby allow a fluid to flow therethrough, and a flow controller controlling a flow passage.