Dispersion Recirculation Assembly for Printing Presses
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Solution Overview
Problem
Existing dispersion preparation and application assemblies for printing materials are costly due to the high expense of high shear mixers and silicone paste, and they require stable emulsions with particle diameters less than 1 µm, which is thermodynamically challenging and expensive to maintain.
Innovation Solution
A dispersion preparation and application assembly that recirculates the dispersion between a mixing tank and a receptacle, using a low shear mixer and allowing for thermodynamically unstable dispersions with particle diameters equal to or greater than 1 µm, eliminating the need for high shear mixers and expensive silicone paste, by incorporating a recirculating device and a withdrawal mechanism to maintain dispersion freshness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a high shear mixer is used to mix the dispersion, then the particle diameter is reduced to less than 1 µm and stability is improved, but the device cost and complexity increase significantly
Solution Approach 1:
The patent extracts the mixing function from a complex high shear mixer and relocates it to a simple recirculating device that moves dispersion between the mixing tank and receptacle. This eliminates the need for specialized high shear mixing equipment while maintaining dispersion stability through continuous circulation and brief mixing periods.
Solution Approach 2:
The system uses dynamic recirculation to maintain dispersion stability. The dispersion is continuously circulated between the mixing tank and receptacle, allowing brief mixing intervals followed by circulation without high shear forces. This dynamic approach replaces static high shear mixing with a time-based circulation process.
2Stability of the object's composition
If a high shear mixer is used to ensure particle diameter less than 1 µm, then dispersion stability is improved, but the equipment cost increases
Solution Approach 1:
The patent uses inexpensive, simple components (recirculating device, piping, pumps) instead of expensive high shear mixers. The system accepts that dispersion stability is temporary (short-living) during the printing process, requiring only brief mixing periods followed by rapid application, eliminating the need for costly specialized equipment.
Solution Approach 2:
The system changes the operational parameters from continuous high shear mixing to intermittent low shear mixing followed by rapid recirculation. This parameter change allows using simple, inexpensive equipment while achieving adequate dispersion stability through time-based control rather than intensive mechanical mixing.
3Device complexity
If stagnant dispersion is allowed to remain in the receptacle, then equipment simplicity is maintained, but the dispersion breaks up and becomes unstable
Solution Approach 1:
The patent implements continuous recirculation of the dispersion between the mixing tank and receptacle. This continuous movement prevents stagnant zones where dispersion would break up, maintaining stability without requiring complex stabilization systems. The useful action of circulation is maintained continuously during operation.
Solution Approach 2:
The system performs preliminary mixing in the mixing tank before the dispersion enters the receptacle. This preliminary action ensures the dispersion is properly mixed before storage, preventing breakdown that would occur if mixing were delayed. The mixing action is completed in advance of the dispersion's residence in the receptacle.
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 assembly provides a simpler, more economical, and reliable method for preparing and applying dispersions, reducing costs and operational complexity while maintaining effective emulsion stability for printing applications.
Implementation Method 1
a recirculating device for recirculating the dispersion between the dispersion receptacle and the mixing tank
Implementation Method 2
a mixer with a rotor and a stator
Implementation Method 3
an applicator for transferring the dispersion from the dispersion receptacle to the printing material
Data Source
Figure 1
Figure 2~3
AI summary
An assembly (100) for preparing an dispersion (180) and applying the dispersion to a printing material, the assembly comprising a reservoir (102) for a first ingredient (124) of the dispersion (180), a supply source (104) for a second ingredient (128) of the dispersion, a mixing tank (106) for receiving the first and second ingredients from the reservoir (102) and the supply source (104) and for mixing at least the first and second ingredients to obtain the dispersion (180), a dispersion receptacle (108) with a dispersion inlet (178) for receiving the dispersion from the mixing tank, and an applicator (110) for transferring the dispersion from the dispersion receptacle (108) to the printing material. The assembly is characterised by a withdrawal device (170) adapted for withdrawing dispersion (180) from the dispersion receptacle (108) which is not picked up by the applicator (110). Preferred use in the application of silicone oil emulsion in a heat set web-fed printing press.