Double Backflow Prevention Valve for Intravenous Catheters

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Solution Overview

Problem

Conventional intravenous catheters face issues with backflow of blood during fluid infusion, leading to potential blockage and difficulty in administering medication due to increased pressure in blood vessels compared to the infused fluid, which causes blood to flow backward through the catheter.

Innovation Solution

An apparatus with a double backflow prevention chamber and member system that includes a first and second prevention member, utilizing a conical shape and elastic support to stepwise open and close fluid pathways, preventing reverse flow while allowing smooth forward flow of fluid.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single check valve is used to prevent backflow, then the structure is simple, but the backflow prevention is unreliable under high pressure conditions

Engineering Contradiction:
Improvebackflow prevention reliabilityVSAvoidvalve structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The check valve is divided into two separate valves (first check valve and second check valve) arranged in series within the catheter. Each valve independently prevents backflow, providing redundant protection. The first check valve is positioned at the distal end while the second check valve is positioned proximal to the injection site, creating multiple barriers against blood backflow into the infusion fluid.

Inventive Principle:
Principle #1Segmentation

2Productivity

If the fluid injector position is lower than the patient's body during injection, then the infusion can proceed, but blood pressure increases causing backflow

Engineering Contradiction:
Improveinfusion flow rateVSAvoidblood backflow
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The dual check valves are pre-positioned within the catheter to counteract the potential backflow force before it can occur. When blood pressure exceeds infusion pressure, the check valves automatically close to prevent backflow, maintaining unidirectional fluid flow even when the injector position is lower than the patient's body.

Inventive Principle:
Principle #9Preliminary anti-action

3Stress or pressure

If blood flows backward through the catheter, then pressure equalization occurs, but platelet necrosis and catheter blockage occur

Engineering Contradiction:
Improvepressure equalizationVSAvoidcatheter blockage
Core Design Contradiction:
Stress or pressureVSObject-generated harmful factors

Solution Approach 1:

The check valves convert the harmful backflow phenomenon into a beneficial unidirectional flow control mechanism. By allowing pressure equalization through controlled valve operation while preventing reverse flow, the system maintains pressure balance without enabling the harmful effects of blood backflow, such as platelet necrosis and catheter blockage.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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

Effectively prevents backflow by stepwise closure of the double backflow prevention member, ensuring a constant flow rate of fluid and preventing blood from flowing backward even under increased pressure conditions, thus maintaining the integrity of the infusion process.

Implementation Method 1

an elastic member provided between the second prevention member and a bottom surface of the first chamber to elastically support and move the first prevention member and the second prevention member

Methodology Applied
Scientific EffectElastic support: Elasticity

Data Source

PatentEP3782694B1Apparatus for preventing backflow
Publication Date: 2024.02.28 ENGAIN CO LTD
  • EP3782694B1 patent drawingFigure 1
  • EP3782694B1 patent drawingFigure 2
  • EP3782694B1 patent drawingFigure 3

AI summary

An apparatus for preventing backflow includes a body forming an accommodating portion which forms a transport passage of a fluid inward, wherein the accommodating portion comprises a double backflow prevention chamber to prevent backflow of the fluid, and a double backflow prevention member provided in the accommodating portion and stepwise implementing opening and closing of the double backflow prevention chamber, In particular, the accommodating portion includes an inflow chamber provided at an upper portion of the body and into which the fluid flows; a discharge chamber through which the fluid is discharged to a lower portion of the inflow chamber; and the double backflow prevention chambers respectively provided at the lower portion of the inflow chamber and the upper portion of the discharge chamber, the double backflow prevention chamber comprising a first chamber provided below the inflow chamber and a second chamber provided below the discharge chamber and connected to the first chamber.