Manual Piston Vacuum Mixing for PMMA Bone Cement
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Solution Overview
Problem
Existing vacuum mixing systems for polymethyl methacrylate bone cement require external vacuum pumps, which are expensive, complex to set up, and can introduce air pockets into the cement dough, leading to suboptimal mixing and increased porosity.
Innovation Solution
A vacuum mixing system with a manually operated piston-driven pump that generates negative pressure within a cartridge, allowing for the separation and mixing of cement powder and monomer liquid without external energy sources, reducing the risk of air inclusions and simplifying the mixing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If external vacuum pumps are used for mixing bone cement, then air pockets can be removed from the cement dough, but the system becomes complex, expensive, and requires external energy sources
Solution Approach 1:
The patent extracts the vacuum generation function from external pumps and integrates it into a manual piston mechanism contained within the mixing cartridge itself. This eliminates the need for external vacuum pumps, complex connecting lines, and external energy sources while maintaining the ability to remove air pockets during mixing.
Solution Approach 2:
The mixing cartridge is designed to be self-sufficient by incorporating a manual piston that can generate vacuum internally. The cartridge serves multiple functions: storing components, generating vacuum, and mixing the cement, eliminating dependence on external equipment and energy sources.
2Manufacturing precision
If external vacuum pumps are used, then vacuum mixing can be achieved, but the setup becomes expensive and requires external energy sources
Solution Approach 1:
The patent replaces the mechanical vacuum pump system (requiring electrical or compressed air energy) with a simple manual piston mechanism. The vacuum is generated through manual mechanical action of the piston within the cartridge, eliminating the need for external energy sources.
3Device complexity
If manual mixing with spatulas is used, then the system is simple, but air pockets remain in the cement dough causing destabilization
Solution Approach 1:
The patent merges the simplicity of manual mixing with the effectiveness of vacuum mixing by integrating a manual piston mechanism directly into the mixing cartridge. The user can manually operate the piston to generate vacuum and mix the cement simultaneously, combining the advantages of both approaches.
4Manufacturing precision
If external vacuum pumps with connecting lines are used, then vacuum can be generated, but the setup takes space and creates tripping hazards
Solution Approach 1:
The patent nests the vacuum generation mechanism (piston and chamber) within the mixing cartridge itself. All components are contained in a compact, integrated unit that occupies minimal space and eliminates the need for external vacuum pumps, connecting lines, and associated infrastructure.
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 system ensures thorough mixing of bone cement components without external energy, reducing porosity and improving mechanical properties of the cement, while being easy to operate and cost-effective, with the ability to function autonomously under simple conditions.
Implementation Method 1
a pump with a manually movable piston for generating a negative pressure... the piston being mounted so that it can move axially in a hollow cylinder... after a complete stroke of the piston within the hollow cylinder, the piston is displaced in such a way that the volume of the hollow cylinder formed pump chamber is at least equal to the volume of the interior of the cartridge to be evacuated
Implementation Method 2
mixing in a vacuum largely removes air inclusions from the cement dough and thus optimal cement quality is achieved. Bone cements mixed in vacuum have a significantly reduced porosity
Implementation Method 3
the cartridge containing a cement powder and the vacuum mixing system having a container separate from the cartridge, in which a monomer liquid is contained, the container having a liquid line connected to the cartridge
Data Source
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AI summary
The invention relates to a vacuum mixing system for mixing polymethyl methacrylate bone cement, comprising at least one cartridge (4) with an evacuable interior for mixing the bone cement, a pump (3) with a manually movable piston (22) for generating a vacuum, and a connecting line (12) that connects the interior of the at least one cartridge (4) to the pump (3) for generating a vacuum, wherein the pump (3) has an externally operable control element (21) which is connected to the piston (22) in such a way that it is suitable for manually moving the piston (22) in the pump (3) so that a vacuum can be generated, so that gas from the interior of the at least one cartridge (4) can be evacuated by means of the vacuum of the pump (3) through the connecting line (12).The invention also relates to a method for mixing polymethyl methacrylate bone cement in an interior of a cartridge (4) of a vacuum mixing system, in particular a vacuum mixing system in which a movement of a manually driven piston (22) of a pump (3) of the vacuum mixing system is used to generate a vacuum in the pump (3), wherein the interior of the cartridge (4) is evacuated with the pump (3) driven in this way, and bone cement is then mixed in the interior of the cartridge (4).