Dialyzer Backflush Cycles for Secondary Membrane Fouling
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Solution Overview
Problem
Existing extracorporeal blood treatment devices face inefficiencies due to secondary membrane formation, which leads to reduced flux and altered selectivity of semipermeable membranes, necessitating time-consuming procedures like rinsing and additional equipment, without providing cost-effective solutions.
Innovation Solution
An extracorporeal blood treatment device with a dialyzer and a processor that intermittently switches between operating modes to remove secondary membrane buildup by controlling dialysate flow through the semipermeable membrane, using a dialysate pump and ultrafiltrate pump, and a computing system to adjust treatment based on sensor data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If secondary membrane is removed by rinsing the blood circuit and changing the filter, then membrane fouling is cleared, but treatment time is lost and treatment must be stopped
Solution Approach 1:
The system performs preliminary actions by detecting membrane fouling through sensor monitoring (electrical conductivity, pressure, temperature) and automatically initiating backflush cycles before treatment must be stopped. This proactive approach maintains membrane performance without interrupting the overall treatment timeline.
Solution Approach 2:
The dialyzer performs self-service by using its own dialysate flow system to conduct backflush cycles that remove secondary membrane buildup. The system uses existing components (dialysate pump, valves, sensors) to clean itself, eliminating the need for external rinsing procedures and filter changes that would stop treatment.
2Productivity
If additional equipment (dialysate lines, sensors, pumps) is added to remove secondary membranes during treatment, then continuous treatment is possible, but device complexity increases
Solution Approach 1:
The system achieves continuous treatment by making existing components multi-functional. The dialysate pump serves both normal dialysis function and backflush operation. Valves are configured to redirect existing dialysate flow paths for cleaning purposes. Sensors monitor both treatment parameters and fouling conditions, enabling one system to perform multiple functions without adding dedicated components for each function.
Solution Approach 2:
The invention merges the secondary membrane removal function with the existing dialysate delivery system. By combining the backflush operation with the normal dialysate flow path and using the same pumps and valves, the system eliminates the need for separate dedicated cleaning equipment, thereby maintaining productivity while controlling complexity.
3Productivity
If dialysate flow is reversed to remove secondary membrane, then membrane flux is restored, but flow control complexity increases
Solution Approach 1:
The system dynamically adjusts dialysate flow direction and magnitude based on real-time sensor feedback. The control system monitors electrical conductivity, pressure, and temperature to detect fouling conditions, then automatically reverses flow direction through valve actuation. This dynamic adaptation allows flux restoration without requiring complex manual intervention or fixed flow control mechanisms.
Solution Approach 2:
The flow reversal mechanism is controlled by feedback from sensors that continuously monitor membrane fouling indicators. When sensors detect changes in electrical conductivity, pressure differential, or temperature that indicate secondary membrane formation, the control system automatically triggers backflush cycles with appropriate flow rates and durations, restoring flux without over-complicating the control system.
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
Efficiently removes secondary membrane during treatment, maintaining treatment efficiency by intermittently reversing dialysate flow to dislodge buildup, thus enhancing the performance of the semipermeable membrane.
Implementation Method 1
The semipermeable membrane selectively allows matter in the blood to flow across the semipermeable membrane from the blood chamber into the dialysate chamber
Implementation Method 2
In a hemofiltration (HF) treatment, blood flows past the semipermeable membrane and undesirable matter and toxins from the blood are pulled across the semipermeable membrane and carried away by dialysate
Implementation Method 3
A dialysate pump is configured to pump dialysate through the dialyzer feed line to the dialysate chamber and from the dialysate chamber out through the dialyzer discharge line
Data Source
AI summary
An extracorporeal blood treatment device and a method are provided for removing a secondary membrane formed on a semipermeable membrane of a dialyzer during an extracorporeal blood treatment. The extracorporeal blood treatment device operates in a first operating mode in which a dialysate outlet valve is open such that dialysate flows through a dialyzer feed line, through a dialysate chamber, and into and through a dialyzer discharge line. The extracorporeal blood treatment device operates in a second operating mode to remove the secondary membrane from the semipermeable membrane. During the second operating mode, the dialysate outlet valve is closed for a duration of time such that dialysate is prevented from flowing through the dialyzer discharge line. A backflush procedure results wherein a volume of dialysate passes from the dialysate chamber through the semipermeable membrane and into the blood chamber.