Pasty Cement Mixing via Axial Partition Deformation
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Solution Overview
Problem
Conventional systems for dispensing highly viscous pasty polymethyl methacrylate bone cements require excessive manual force or complex electrical/pneumatic systems, which are costly, cumbersome, and difficult to sterilize, and often result in inefficient mixing and dispensing due to high flow resistance and energy loss from cutting processes in coaxial cartridges.
Innovation Solution
A storage and mixing system featuring a tubular cartridge with an axial partition that separates two pasty cement components, allowing for manual operation using a single push rod and bending device to deform the partition, reducing energy requirements and enabling efficient mixing and dispensing through a static mixer in a dispensing tube.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional systems are used to dispense highly viscous pasty polymethyl methacrylate bone cements, then the cement can be dispensed, but excessive manual force or complex electrical/pneumatic systems are required, increasing device complexity and cost
Solution Approach 1:
The cartridge is divided into two separate chambers by a partition wall, with each chamber containing a separate cement component. This segmentation allows independent dispensing of each component through separate plungers, reducing the complexity required to handle the viscous material compared to a single-chamber system.
Solution Approach 2:
The second cartridge is positioned coaxially within the first cartridge, with the partition wall separating the two chambers. This nested arrangement allows both components to be stored and dispensed within a single external cartridge structure, simplifying the overall device while maintaining separate storage compartments.
2Productivity
If coaxial cartridges with cutting processes are used, then mixing can be achieved, but energy loss occurs and the process becomes less efficient
Solution Approach 1:
The cutting process is extracted and eliminated from the mixing mechanism. Instead of using rotating blades or cutting elements to mix the cement components, the invention relies on the mechanical mixing action produced by the plungers pushing the viscous material through the narrow gap between the coaxial cartridges, achieving mixing without energy-intensive cutting processes.
3Ease of manufacture
If a single cartridge with partition is used, then assembly steps are reduced, but the partition must be deformed during dispensing, requiring additional force
Solution Approach 1:
The partition wall is designed as a dynamic element that can be deformed during the dispensing process. As the plungers move and apply force to the viscous cement material, the partition wall flexes and deforms to allow the material to pass through the narrow gap between the cartridges, eliminating the need for complex mechanical deformation mechanisms while requiring only the natural dispensing force.
Data Source
AI summary
Storage and mixing systems for pasty two-component polymethyl methacrylate bone cements comprise a tubular cartridge having a cylindrical inner chamber, a cartridge head, which closes one end of the tubular cartridge at the front side, a partition that is disposed axially in the cylindrical inner chamber of the cartridge. The partition divides the cylindrical inner chamber of the cartridge bounded by the cartridge head into two cavities that are spatially separated from one another, wherein a first pasty cement component is present in the first cavity and a second pasty cement component is present in the separate second cavity. The systems further comprising two dispensing plungers axially displaceable in the two cavities of the cartridge, wherein the dispensing plungers close the two cavities on the back side of the cavities situated opposite the cartridge head, a bending device for deforming the partition, wherein the bending device is axially movable in the cartridge and is disposed, or is to be disposed, behind the dispensing plungers, as seen from the cartridge head, wherein the bending device has a deflection surface that is inclined with respect to the axis of the cartridge and pushes the partition laterally in the direction of the inside wall of the cartridge when the bending device is pushed into the cartridge.