Multi-Plunger Inflation Device Force Reduction

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Solution Overview

Problem

Existing medical inflation devices require high input forces to achieve high pressure, especially when using large diameter syringes, and struggle with rapid inflation/deflation cycles necessary for procedures like valvuloplasty, where quick pressure changes between heartbeats are needed.

Innovation Solution

The development of an inflation device with multiple plungers that can automatically toggle between large and small plungers, allowing for selective locking and unlocking to reduce the force required for high-pressure inflation and enable rapid pressure changes, using a combination of locking mechanisms and angled surfaces to manage plunger movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If a large diameter syringe is used to achieve high pressure, then the fluid volume capacity is improved, but the input force required increases significantly

Engineering Contradiction:
Improvefluid volume capacityVSAvoidinput force required
Core Design Contradiction:
Quantity of substanceVSForce

Solution Approach 1:

The inflation device divides the single plunger into multiple plungers (first plunger, second plunger, third plunger) with different cross-sectional areas. Each plunger handles a specific phase of inflation: the first plunger with larger area handles initial volume displacement, while the second and third plungers with smaller areas handle high-pressure phases. This segmentation allows the system to achieve both high fluid volume capacity and reduced input force by matching plunger area to the specific inflation phase requirements.

Inventive Principle:
Principle #1Segmentation

2Device complexity

If a single plunger is used for inflation, then the device structure is simple, but the ability to perform rapid inflation/deflation cycles is limited

Engineering Contradiction:
Improvedevice structureVSAvoidrapid inflation/deflation capability
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The device incorporates dynamic switching between multiple plungers based on the inflation phase. The locking mechanism allows automatic transition from the first plunger to the second and third plungers as pressure increases. This dynamic reconfiguration enables rapid deflation by simply retracting the active plunger, facilitating quick inflation/deflation cycles necessary for procedures like valvuloplasty without requiring complete device disassembly or complex valve systems.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent replaces traditional complex valve mechanisms with a plunger-based system where inflation and deflation are controlled by advancing and retracting different plungers. The locking mechanism uses mechanical engagement between the plunger and syringe body to seal the system, eliminating the need for complex valve assemblies and enabling faster response times for pressure changes.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Stress or pressure

If high pressure is achieved using a single plunger, then the pressure level is sufficient, but the input force becomes excessively high

Engineering Contradiction:
Improveinflation pressureVSAvoidinput force
Core Design Contradiction:
Stress or pressureVSForce

Solution Approach 1:

The device applies local quality by assigning different cross-sectional areas to different plungers based on the specific inflation phase. The first plunger has a larger cross-sectional area optimized for initial volume displacement at lower pressures, while the second and third plungers have smaller cross-sectional areas optimized for high-pressure phases. This local optimization of plunger geometry allows the system to achieve high inflation pressure with reduced input force by matching plunger area to the specific pressure phase.

Inventive Principle:
Principle #3Local quality

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

This solution significantly reduces the force needed for high-pressure inflation, allowing for efficient and rapid fluid displacement, enabling procedures like valvuloplasty by minimizing the input force required and facilitating quick pressure changes between heartbeats.

Implementation Method 1

locking mechanisms and angled surfaces to manage plunger movement

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

locked in a locked configuration... forces required to reach particular inflation pressures

Methodology Applied
Scientific EffectNormal force: Force

Data Source

PatentEP2897679B1Variable displacement inflation devices and methods of use
Publication Date: 2020.12.23 MERIT MEDICAL SYSTEMS INC
  • EP2897679B1 patent drawingFigure 1
  • EP2897679B1 patent drawingFigure 2
  • EP2897679B1 patent drawingFigure 3

AI summary

An inflation device that may comprise multiple plungers is disclosed. The inflation device may have multiple configurations wherein certain plungers are locked with respect to a body of the inflation device while others are configured to be displaceable within the body. Each plunger may be configured with a different effective surface area, allowing a practitioner to vary the amount of force required to attain certain pressures.