Bone Cement Mixing System with Piston-Controlled Monomer Transfer
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Solution Overview
Problem
Existing prepackaged mixing systems for PMMA bone cement face challenges in safely and reliably transferring monomer liquid without conduit blockage and air inclusion, which can affect mechanical properties.
Innovation Solution
A device comprising a base part with a container for monomer liquid and a cartridge for PMMA bone cement powder, featuring a self-sealing connection system with a hollow mandrel and piston to ensure controlled mixing, preventing conduit blockage and air inclusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If monomer liquid is transferred into the cartridge using vacuum or pressure transfer, then complete transfer can be achieved, but conduit blockage by swollen cement particles may occur
Solution Approach 1:
A filter element is introduced as an intermediary component in the monomer liquid transfer conduit. This filter selectively allows monomer liquid to pass through while blocking swollen cement particles, preventing conduit blockage during the transfer process. The filter element serves as a mediator between the monomer liquid and the cement powder, ensuring smooth transfer without contamination.
Solution Approach 2:
The filter element is constructed from porous material that permits fluid passage while retaining solid particles. The porous structure allows monomer liquid to flow through during transfer, yet effectively blocks swollen cement particles from clogging the conduit, thus maintaining reliable operation throughout the mixing process.
2Ease of operation
If powder component is mixed with monomer liquid using spatulas in mixing cups, then mixing can be performed, but air bubbles are included which negatively affect mechanical properties
Solution Approach 1:
The mixing system is designed to operate in a vacuum environment, removing air bubbles from the mixing chamber before and during the mixing process. This inert atmosphere prevents air entrapment in the bone cement dough, ensuring homogeneous mixing without bubbles that would compromise mechanical properties.
Solution Approach 2:
Vacuum technology is applied to the mixing system, using negative pressure to draw air bubbles out of the mixing chamber during the mixing process. The vacuum mechanism hydraulically removes trapped air, ensuring complete mixing without bubble formation, thereby improving the quality of the final bone cement product.
3Adaptability or versatility
If cement powder penetrates the monomer liquid transfer conduit during transport and storage, then mixing can occur, but the conduit becomes blocked due to swelling and sticking
Solution Approach 1:
The filter element acts as a protective intermediary in the transfer conduit, allowing monomer liquid to pass through while preventing cement powder particles from entering and blocking the conduit. This mediator ensures the conduit remains clear during storage and transport, maintaining reliability until mixing is required.
Solution Approach 2:
The system is divided into separate functional zones: a storage compartment for cement powder and a transfer conduit for monomer liquid, separated by the filter element. This segmentation prevents interaction between powder and liquid during storage, eliminating the risk of conduit blockage while maintaining mixing capability when needed.
4Quantity of substance
If a mesh or porous disk is used to block cement powder particles, then complete monomer liquid transfer is enabled, but device complexity increases
Solution Approach 1:
A porous filter element is integrated into the transfer conduit, utilizing the porous structure to allow monomer liquid passage while blocking cement particles. This single component solution achieves complete liquid transfer without requiring complex multi-part assemblies, thus limiting the increase in device complexity.
Solution Approach 2:
The filter element serves multiple functions simultaneously: it blocks cement particles, allows monomer liquid transfer, and can be integrated into existing cartridge designs. This multi-functionality reduces the need for additional separate components, minimizing the overall increase in device complexity while achieving complete transfer.
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
Ensures safe, reliable, and complete transfer of monomer liquid into the powder, producing a consistent bone cement dough without air bubbles, enhancing mechanical properties.
Implementation Method 1
the monomer liquid can be transferred into the cartridge either by vacuum or, alternatively, by pressure transfer of the monomer liquid using a manually operated pump piston integrated into the mixing system
Implementation Method 2
piercing the septum with the hollow mandrel in order to transfer a monomer liquid from the collection area into the cartridge
Implementation Method 3
The cartridge has a septum which delimits the cartridge to the outside
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
A device for producing bone cement, comprising a base part (100) which has a container (101) with a carrier (118) for receiving a vessel with monomer liquid, a bottom part (103) with a collection area (104), a hollow mandrel (105) with a tip (106), and a piston (107) with a passage (108) for receiving the hollow mandrel, and a cartridge (200) for receiving a PMMA bone cement powder (201), wherein the cartridge has a septum (202) which delimits the cartridge to the outside; wherein the piston is configured, in a basic configuration of the device, to receive the tip of the hollow mandrel in the passage and to release the tip of the hollow mandrel from the passage and, at the same time, to release a monomer liquid from a vessel when the cartridge is pressed onto the piston.