Hemodialysis Backflow Prevention via Segmented Hydrochamber
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Solution Overview
Problem
Hemodialysis devices face the risk of backflow contamination during chemical disinfection operations when the external water source loses pressure, as the disinfectant can potentially flow back through the water inlet valve, compromising patient safety.
Innovation Solution
A hemodialysis system with a hydrochamber, water circuit, spent dialysate circuit, and dual valve manifold is designed to prevent backflow by isolating the flow paths and using a recirculation valve directly connected to the hydrochamber, ensuring the disinfectant does not backflow through the water inlet valve even during pressure drops, and includes an air gap and a controller for alarm generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the recirculation valve is opened during disinfectant operation, then the disinfectant can flow through the spent dialysate circuit to the hydrochamber, but the risk of backflow contamination through the water inlet valve increases when external water pressure is lost
Solution Approach 1:
The system segments the flow paths by providing separate inlet ports: a first inlet port for water and a second inlet port for disinfectant. The recirculation valve connects only to the second inlet port, creating an isolated pathway that prevents disinfectant from backflowing through the water inlet path even when water pressure is lost.
Solution Approach 2:
The recirculation valve acts as an intermediary component that introduces disinfectant through a dedicated pathway. By routing disinfectant through the second inlet port and recirculation valve rather than the water inlet valve, the system mediates between the need for disinfection and the need to prevent backflow contamination.
2Device complexity
If the water inlet valve and recirculation valve share a common connection to the hydrochamber, then the device structure is simpler, but the flow paths are not isolated and backflow prevention is compromised
Solution Approach 1:
The hydrochamber is segmented to have separate inlet ports: a first inlet port for water and a second inlet port for disinfectant. This segmentation isolates the flow paths, ensuring that the recirculation valve connected to the second inlet port cannot allow disinfectant to backflow through the water inlet valve connected to the first inlet port.
Solution Approach 2:
Different regions of the hydrochamber are assigned different functions: the first inlet port region handles water flow while the second inlet port region handles disinfectant flow. This local differentiation ensures that each inlet serves its specific purpose and prevents cross-contamination between water and disinfectant pathways.
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 system effectively prevents backflow contamination during disinfectant operations by maintaining independent flow paths and using a recirculation valve connected to the hydrochamber, ensuring patient safety by isolating the disinfectant from the water inlet valve, even when external water pressure is lost.
Implementation Method 1
The recirculation valve is directly connected to the hydrochamber such that in response to a pressure drop at the external water source, the disinfecting agent is prevented from back-flowing through the water inlet valve
Data Source
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Figure 2A~2B
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AI summary
A hemodialysis system according to an embodiment of the present invention includes a hydrochamber, and a water circuit for water to flow from an external water source into the hydrochamber via a water inlet valve. The hemodialysis system further includes a spent dialysate circuit for a disinfecting agent to flow to the hydrochamber via a recirculation valve during a disinfectant operation, and a drain valve disposed in the spent dialysate circuit. During the disinfectant operation, the hemodialysis system is adapted to replace a volume of the disinfecting agent exiting the spent dialysate circuit via the drain valve with an equal volume of water via the water inlet valve. The recirculation valve is directly connected to the hydrochamber such that in response to a pressure drop at the external water source, the disinfecting agent is prevented from backflowing through the water inlet valve.