Vacuum Mixing Device for Bone Cement Using Inert Gas Displacement

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Solution Overview

Problem

Conventional vacuum mixing devices for bone cement are complex to operate, prone to contamination, and require precise mixing ratios, which can lead to errors and germ introduction from ambient air.

Innovation Solution

A self-contained vacuum mixing device with a monomer container pre-filled with gas, allowing the monomer to be displaced by vacuum into the mixing chamber, preventing air contamination and enabling simple, safe handling, with a design that ensures exact calibration and secure monomer delivery.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If a valve is used to allow air flow into the monomer container, then the monomer can be completely evacuated, but the bone cement becomes contaminated with germs from ambient air

Engineering Contradiction:
Improvemonomer evacuation completenessVSAvoidgerm contamination
Core Design Contradiction:
Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The monomer container is filled with an inert gas (nitrogen or carbon dioxide) to replace the air above the monomer. This creates a sterile, germ-free environment that prevents contamination while allowing complete evacuation of the monomer through the vacuum connection.

Inventive Principle:
Principle #39Inert atmosphere (Inert environment)

2Reliability

If conventional vacuum mixing systems are used, then bubbles can be prevented, but the operation becomes complex and error-prone

Engineering Contradiction:
Improvebubble preventionVSAvoidoperational complexity
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The monomer container is pre-filled with inert gas before use. This preliminary action eliminates the need for complex operational steps during mixing, as the sterile environment is already established and the system is ready for immediate use without requiring multiple manual interventions.

Inventive Principle:
Principle #10Preliminary action

3Ease of manufacture

If the monomer container is opened to the ambient environment, then filling is simple, but the mixing ratio precision and sterility are compromised

Engineering Contradiction:
Improvefilling simplicityVSAvoidmixing ratio precision
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The inert gas atmosphere in the monomer container maintains a sealed, controlled environment that prevents ambient air contamination. This ensures precise mixing ratios by preventing evaporation or contamination of the monomer while maintaining sterility throughout the process.

Inventive Principle:
Principle #39Inert atmosphere (Inert environment)

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 solution simplifies the operation of the vacuum mixing device, prevents contamination, and ensures accurate monomer delivery, enhancing safety and ease of use while maintaining a sterile environment.

Implementation Method 1

a vacuum mixing device for bone cement, which comprises a mixing space in which a monomer can be mixed with the powder. In order to prevent the formation of bubbles and the escape of harmful gases, the mixing chamber can be connected to a vacuum source

Methodology Applied
Scientific EffectVacuum: Vacuum

Implementation Method 2

The monomer container is preferably not pressurized, but is, for example, at essentially atmospheric pressure... If, for example, the monomer container is at atmospheric pressure and a vacuum source is applied which creates a vacuum of about 0.5 bar in the mixing container

Methodology Applied
Scientific EffectPressure difference: Pressure Gradient

Data Source

PatentEP2408403B1Vacuum-mixing device for bone cement and process for mixing bone cement in said device
Publication Date: 2019.05.29 STRYKER EUROPEAN HOLDINGS I LLC
  • EP2408403B1 patent drawingFigure 1
  • EP2408403B1 patent drawingFigure 2
  • EP2408403B1 patent drawingFigure 3

AI summary

The application relates to a vacuum mixing device (1) for bone cement, where the monomer is pressed into a mixing container (2) due to the surrounding vacuum and a gas volume present in the monomer container (10).