Synchronized Plunger Pumps for Pulsation-Free Dialysate Flow
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Solution Overview
Problem
Existing blood purification devices require separate pumps for water removal and backfiltration, increasing costs and failing to simultaneously supply fresh and used dialysate without pulsation.
Innovation Solution
A blood purification device with a pair of synchronized plunger pumps in the dialysate line, where one pump delivers fresh dialysate and the other suction used dialysate, with adjustable stroke and phase synchronization to stabilize dialysate pressure and enable simultaneous supply and discharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate pumps are used for water removal and backfiltration, then water removal and backfiltration functions are achieved, but device complexity and cost increase
Solution Approach 1:
The patent applies multi-functionality by enabling a single plunger pump to perform multiple functions: fresh dialysate supply, used dialysate discharge, water removal, and backfiltration. The pump achieves this through variable stroke control and phase adjustment mechanisms, eliminating the need for separate water removal and backfiltration pumps, thereby reducing device complexity while maintaining all required functions
Solution Approach 2:
The patent employs dynamics by making the plunger pump stroke variable and adjustable. The stroke length can be dynamically changed to control the volume of dialysate moved, enabling the same pump to perform different functions (supply vs. discharge vs. water removal vs. backfiltration) by adjusting operational parameters rather than requiring separate fixed-function pumps
2Productivity
If reciprocating pumps are used for dialysate supply and discharge, then dialysate flow is achieved, but pulsation occurs in the fresh dialysate supply
Solution Approach 1:
The patent applies periodic action by using two plunger pumps operating in alternating phases. While one pump delivers fresh dialysate, the other sucks used dialysate, and vice versa. This periodic alternation creates a continuous, non-pulsating flow because the suction phase of one pump compensates for the delivery phase of the other, maintaining stable pressure and flow in the dialysate supply line
Solution Approach 2:
The patent uses preliminary action by synchronizing the pumps so that the suction phase begins before the delivery phase ends. This overlapping timing ensures continuous flow without interruption or pulsation, as the second pump's suction action prepares for and smooths the transition between delivery phases
3Productivity
If synchronized plunger pumps with variable stroke are used, then simultaneous supply and discharge of dialysate is achieved, but pump mechanism complexity increases
Solution Approach 1:
The patent applies asymmetry by allowing the two plunger pumps to have different stroke lengths while maintaining synchronized operation. One pump can have a longer stroke for supply while the other has a shorter stroke for discharge, or vice versa. This asymmetric configuration enables flexible control of supply and discharge volumes simultaneously without requiring complex differentiating mechanisms for each pump
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
Enables simultaneous supply and discharge of fresh and used dialysate without pulsation, reducing costs by eliminating the need for additional pumps and improving dialysate management in blood purification.
Implementation Method 1
a synchronization motor 50 and drive joints 6, 7
Implementation Method 2
a pair of plunger pumps 51, 52 disposed in the dialysate line 4
Data Source
AI summary
In a blood purification device containing a blood purifier, a blood circuit, a blood pump, and a dialysate line having a fresh dialysate supply line and a used dialysate discharge line, a pair of plunger pumps are disposed in the dialysate line. The pair of plunger pumps are synchronized so that delivery of a fresh dialysate from one plunger pump and suction of a used dialysate into the other plunger pump simultaneously occur and the stroke of at least one of the pair of plunger pumps is made variable.