PMMA Bone Cement Mixing Device with Pressure Pump and Ampoule Breaker
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Solution Overview
Problem
Existing vacuum mixing systems for polymethyl methacrylate bone cement require external vacuum pumps and energy sources, leading to complexity, potential air inclusions, and increased operational time, which can compromise the mechanical properties of the cement.
Innovation Solution
A closed, full-prepacked mixing device that allows for the manual mixing of cement powder and monomer liquid without external vacuum sources, using a pump plunger and deformable side walls to transfer the monomer liquid into the cement powder, ensuring controlled mixing and minimizing air inclusions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If external vacuum pumps are used to mix bone cement, then air inclusions can be avoided, but device complexity and operational time increase
Solution Approach 1:
The invention extracts and eliminates the need for external vacuum pumps by using an internal mixing mechanism where the monomer liquid flows through the cement powder under its own weight and pressure, naturally displacing air without requiring external vacuum equipment
Solution Approach 2:
The mixing system is self-sufficient, using the pressure generated by the monomer liquid itself and the mixing action within the cartridge to achieve thorough mixing and air removal without external energy sources or vacuum pumps
2Reliability
If external vacuum pumps are used to mix bone cement, then air inclusions can be avoided, but operational time increases
Solution Approach 1:
The cartridge is pre-filled with cement powder and the monomer liquid is pre-loaded in the ampoule before use, allowing immediate mixing upon activation without preparation time for vacuum equipment or separate filling steps
3Ease of operation
If monomer liquid is transferred into cement powder, then mixing is achieved, but air inclusions may form
Solution Approach 1:
Instead of introducing air into the mixture or allowing air to be trapped during conventional mixing, the system inverts the approach by having the monomer liquid flow through the powder from the bottom up, naturally pushing air bubbles out through the delivery plunger as the mixture forms
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 device enables reliable, efficient mixing of polymethyl methacrylate bone cement without external energy sources, reducing the risk of air inclusions and simplifying the mixing process, thereby improving the mechanical properties and usability of the cement.
Implementation Method 1
a pump plunger (2, 62) arranged to be axially movable in the hollow cylinder (1, 61), wherein, by pressing the pump plunger (2, 62) into the hollow cylinder (1, 61), the opening device (3, 63) is pressed against the deformable side wall (6, 66)
Implementation Method 2
a screen and/or a filter (18, 78, 102) which is or are arranged below the receptacle (4, 64) so that the contents of the opened monomer liquid container flow through the screen and/or filter (18, 78, 102)
Implementation Method 3
a mixing device (20, 80), which is externally operable, arranged in the cartridge (8, 68), wherein the mixing device (20, 80) is operated by way of a mixing rod (22, 82), which is guided into the interior of the cartridge (8, 68) to be rotatable and longitudinally displaceable
Implementation Method 4
When the powder component is mixed with the monomer component, the N,N-dimethyl-p-toluidine activator reacts with dibenzoyl peroxide, forming radicals. The radicals formed initiate the radical polymerization of the methyl methacrylate
Implementation Method 5
When mixing the powder component with the monomer component, a plastically deformable paste, the actual bone cement, is obtained as a result of the polymers of the powder component swelling in the methyl methacrylate
Data Source
AI summary
A device mixes bone cement and stores parent components of the bone cement. The device has a cartridge comprising an interior, that is closed on one side by a movable delivery plunger, a receptacle comprising side walls for receiving a monomer liquid container that are closed at least in some regions. The receptacle has at least one deformable closed side wall, a screen and/or a filter arranged below the receptacle so that the contents of the opened monomer liquid container flow through the screen and/or the filter. The device further has a connecting line through which the monomer liquid is to be routed into the interior of the cartridge, a hollow cylinder which is connected to the connecting line and which is connected to the receptacle by way of a fluid connection so that the hollow cylinder is arranged in a fluid line between the receptacle and the interior of the cartridge. A pump plunger is arranged in the hollow cylinder, which is axially displaceable in the hollow cylinder, and an opening device, which is movably mounted against the deformable side wall of the receptacle. The opening device extends into the hollow cylinder, wherein, by pressing the pump plunger into the hollow cylinder, the opening device is to be pressed against the deformable side wall of the receptacle so that the deformable side wall deforms such that a monomer liquid container located in the receptacle is to be opened by the pressure of the opening device.