Two-part Plunger System for Bone Cement Mixing and Sterilization
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Solution Overview
Problem
Existing bone cement mixing systems face contamination risks due to the need to open and re-seal the cement cartridge for vacuum mixing, which can introduce germs into the previously disinfected bone cement powder, especially when using ethylene oxide sterilization.
Innovation Solution
A two-part plunger system is introduced, where a sterilization plunger allows gas permeability for ethylene oxide sterilization and a sealing plunger ensures a gas-tight vacuum seal for mixing, preventing contamination and enabling efficient disinfection and vacuum mixing without compromising the sterilization process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single plunger system is used to seal the mixing cylinder, then the structure is simple, but it cannot simultaneously provide gas-permeable sterilization and gas-tight vacuum sealing
Solution Approach 1:
The single plunger system is divided into two separate plungers: a sterilization plunger with gas-permeable properties for sterilization, and a sealing plunger with gas-tight properties for vacuum sealing. This segmentation allows each plunger to be optimized for its specific function while working together as a coordinated system.
Solution Approach 2:
The two-part plunger system provides multiple functions within a single integrated structure: sterilization through gas-permeable contact, vacuum sealing through gas-tight contact, and coordinated movement through shared actuation. This multi-functionality resolves the contradiction by combining specialized functions into a unified system.
2Ease of operation
If the mixing cylinder is opened for vacuum mixing, then mixing can be performed, but contamination risk increases due to exposure to non-sterile environment
Solution Approach 1:
The sterilization plunger is positioned to allow ethylene oxide gas to penetrate and sterilize the bone cement powder before mixing. This preliminary sterilization action ensures the powder remains sterile throughout storage and handling, eliminating contamination risk when the cylinder is later opened for vacuum mixing.
Solution Approach 2:
The gas-permeable sterilization plunger acts as an intermediary that allows sterilization gas to pass through while maintaining a physical barrier. This intermediary structure enables sterilization without requiring complete opening of the system, thus preventing contamination during the mixing operation.
3Stability of the object's composition
If ethylene oxide sterilization is used, then polymer degradation is avoided, but gas penetration and diffusion require unimpeded gas exchange which conflicts with vacuum sealing requirements
Solution Approach 1:
The plunger system is segmented into two functional parts: the sterilization plunger with gas-permeable properties that enables ethylene oxide penetration during sterilization, and the sealing plunger with gas-tight properties that enables vacuum sealing during mixing. This segmentation resolves the gas exchange contradiction by providing separate pathways for sterilization and sealing functions.
Solution Approach 2:
The two plungers can move independently along the actuation rod, allowing dynamic configuration of the system. The sterilization plunger can be retracted to allow gas permeability during sterilization, while the sealing plunger can be positioned to create gas-tight seals during vacuum mixing, providing dynamic adaptability to different operational requirements.
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 two-part plunger system effectively disinfects the bone cement powder while maintaining a vacuum-tight seal for optimal mixing, reducing the risk of contamination and ensuring high-quality bone cement production.
Implementation Method 1
a sterilization plunger (41) which seals the mixing cylinder (20) in a gas-permeable manner
Implementation Method 2
a sealing plunger (42) which seals the mixing cylinder (20) in a gas-tight manner
Implementation Method 3
a mixing plunger (21) which can be moved axially by an actuation rod (50)
Implementation Method 4
an actuation rod (50) which is guided out in a sealed manner at a first cylinder end (30)
Data Source
AI summary
A device (10) for mixing and dispensing bone cement includes a mixing cylinder (20), in which a mixing plunger (21) is arranged, the mixing plunger (21) being axially movable by an actuation rod (50) guided out in a sealed manner at a first cylinder end (30). A sealing plunger (42) is arranged in a region of the first cylinder end (30), is axially movable on the actuation rod (50) and seals the mixing cylinder (20) in a gas-tight manner. A sterilization plunger (41) is arranged in the region of the first cylinder end (30) between the mixing plunger (21) and the sealing plunger (42), is axially movable on the actuation rod (50) separately from the sealing plunger (42), and seals the mixing cylinder (20) in a gas-permeable manner. The sterilization plunger (41) and the sealing plunger (42) form a two-part plunger system (40).