Blood Return Circuit Pressurization to Prevent Negative Pressure

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Solution Overview

Problem

Existing blood purification apparatuses face issues with negative pressure formation in the blood circuit during blood return procedures, particularly when power supply is interrupted, leading to undesirable conditions.

Innovation Solution

A blood purification apparatus is designed with an air introduction route to set the dialysate circuit to positive pressure, using air introducers and a controller to manage dialysate flow, thereby preventing or alleviating negative pressure in the blood circuit.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the blood pump is rotated to draw dialysate into the blood circuit, then blood return is enabled, but negative pressure is generated in the blood circuit

Engineering Contradiction:

Improveblood return functionVSAvoidnegative pressure in blood circuit

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces air as an intermediary substance into the dialysate circuit. This air acts as a mediator that generates positive pressure to push dialysate into the blood circuit, thereby eliminating the need for the blood pump to rotate and preventing negative pressure formation in the blood circuit during blood return

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

Instead of using the blood pump to actively draw dialysate into the blood circuit (which creates negative pressure), the patent inverts the approach by introducing air into the dialysate circuit to passively push dialysate into the blood circuit through pressure differential, reversing the traditional active suction mechanism

Inventive Principle:

Principle #13The other way round (Inversion)

2Reliability

If air is introduced into the filter through the air introduction line, then dialysate can be drawn into the blood circuit, but the circuit portion at the entrance side of the blood pump becomes prone to negative pressure

Engineering Contradiction:

Improveblood return capabilityVSAvoidnegative pressure in blood circuit

Core Design Contradiction:

ReliabilityVSStress or pressure

Solution Approach 1:

Air is introduced as an intermediary into the dialysate circuit to generate positive pressure that pushes dialysate into the blood circuit, eliminating the need for blood pump rotation and preventing negative pressure formation in the blood circuit during blood return

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent utilizes pneumatic pressure by introducing air into the dialysate circuit to create a pressure differential that drives dialysate flow into the blood circuit, replacing the mechanical hydraulic approach of using the blood pump to draw fluid

Inventive Principle:

Principle #29Pneumatics and hydraulics

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 apparatus effectively returns blood to the patient by maintaining positive pressure in the dialysate circuit, ensuring safe and efficient blood return even during power outages.

Implementation Method 1

an air introducer provided to any of the dialysate circuit and the air introduction route and configured to set the dialysate circuit to a positive pressure by introducing air into the dialysate circuit through the air introduction route

Methodology Applied

Scientific EffectGas introduction to create pressure: Pressure Increase

Implementation Method 2

feed a dialysate from the dialysate circuit to the blood circuit

Methodology Applied

Scientific EffectPressure-driven fluid flow: Pressure Gradient

Data Source

PatentUS20260034282A1Blood Purification Apparatus

Publication Date: 2026.02.05 NIKKISO CO LTD

AI summary

Provided is a blood purification apparatus that returns blood in a blood circuit to a body. A blood purification apparatus includes: a blood circuit and a dialysate circuit coupled to each other through a blood purifier; an air introduction route coupled to the dialysate circuit; an air introducer provided to any of the dialysate circuit and the air introduction route and configured to set the dialysate circuit to a positive pressure by introducing air into the dialysate circuit through the air introduction route; and a controller configured to control the air introducer in such a way as to feed a dialysate from the dialysate circuit to the blood circuit, and to control the blood circuit and the dialysate circuit in such a way as to return blood in the blood circuit and the blood purifier to a body by feeding the dialysate from the dialysate circuit to the blood circuit.