Bone Cement Mixing System with Sieve and Baffle
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Solution Overview
Problem
Current bone cement mixing systems face issues with air pockets and incomplete mixing, leading to destabilization and unpredictable mechanical properties due to potential clogging by bone cement powder, especially with high-viscosity PMMA cements.
Innovation Solution
A bone cement system with a mixing device featuring a sieve element and a discharge opening with a specific aperture ratio and distance, allowing for controlled monomer injection and mixing, preventing powder clogging and ensuring complete monomer transfer, and a discharge mechanism to remove the mixed cement effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sieve element is arranged between the storage container and the mixing device to prevent bone cement powder from flowing out, then powder clogging is prevented, but uniform and rapid mixing of monomer with bone cement powder cannot always be ensured
Solution Approach 1:
The patent introduces an intermediate space between the sieve element and the mixing cylinder, which acts as a mediator. This space allows the monomer to be injected under pressure through a nozzle that directs it onto the bone cement powder, ensuring rapid and uniform mixing while the sieve element continues to prevent powder from clogging the conduit. The intermediate space decouples the conflicting requirements of powder containment and efficient mixing.
2Productivity
If monomer liquid is introduced into the center of cement powder by vacuum through tubes, then mixing can be achieved, but cement powder may penetrate into the tubes and cause blockage
Solution Approach 1:
Instead of introducing the monomer liquid upward through tubes into the cement powder (which risks powder penetration and blockage), the patent inverts the approach by placing the sieve element at the bottom to prevent powder escape, and injecting the monomer downward or laterally through a nozzle in the intermediate space onto the powder surface. This reversal of the monomer introduction direction eliminates the blockage risk while maintaining mixing effectiveness.
3Manufacturing precision
If vacuum mixing systems are used to remove air inclusions, then cement quality is improved, but air pockets can still be present in manually mixed cement
Solution Approach 1:
The patent extracts the air removal function from the mixing process itself by designing a system where the monomer is injected in a controlled manner that minimizes air entrapment. The intermediate space and nozzle design allow the monomer to penetrate and distribute through the powder without creating air pockets, achieving high cement quality without requiring complex vacuum mixing equipment. This extracts the essential quality improvement while eliminating the need for complex vacuum systems.
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
This solution ensures uniform and complete mixing of bone cement components, reducing porosity and improving mechanical properties by preventing powder clogging and ensuring consistent monomer distribution, resulting in a more reliable and stable bone cement paste.
Implementation Method 1
a sieve element (4) is arranged between the storage container and the mixing device in order to prevent the bone cement powder from flowing out of the mixing cylinder into the line means
Implementation Method 2
The monomer liquid can be injected under pressure through a nozzle (22) which is directed onto the bone cement powder (3) in a gap (200)
Implementation Method 3
a mixing piston (21) is arranged in the mixing cylinder (20), the mixing piston (21) being axially movable by means of an actuating rod (50)
Implementation Method 4
the mixing piston (21) being axially movable by means of an actuating rod (50) which is led out sealed at a first cylinder end (30)
Data Source
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AI summary
The invention relates to a bone cement system (100) with a mixing device (10) for mixing and dispensing bone cement, a reservoir (112) for a monomer and a conveying medium (122), wherein the mixing device (10) has a mixing cylinder (20), the mixing cylinder (20) stores a bone cement powder, the monomer can be conveyed from the reservoir (112) into the mixing cylinder (20) by means of the conveying medium (122), a sieve element (4) is arranged between the reservoir (112) and the mixing device (10) to prevent the bone cement powder from flowing from the mixing cylinder (20) into the conveying medium (122), and the mixing device (10) has a discharge opening (23) to discharge a bone cement mixed from the bone cement powder and the monomer.According to the invention, the discharge opening (23) has a baffle (1) with at least one through-opening (2), and the ratio of the area of the through-opening (2) to the area of the sieve element (4) is at least 1 to 3, and the distance between the baffle (1) and the sieve element (4) is at least 1 mm.