Rotating Drum Coating for Uniform Droplet Deposition
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Solution Overview
Problem
Existing dripping devices for free-flowing products face issues with wetting and residue formation on the outer drum, leading to uneven deposition and reduced output, as well as the formation of secondary drops due to product residues.
Innovation Solution
A rotating outer drum with a coating on its circumference and through openings, which reduces wetting and prevents residue formation, allowing for improved drop detachment and deposition on a steel belt without secondary drops, using a nanocoating or flowable medium that forms a hydrophobic or superhydrophobic surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional outer drum without coating is used, then the structure is simple and easy to manufacture, but the product droplets adhere to the outer drum surface causing uneven deposition and residue formation
Solution Approach 1:
A coating layer is introduced as an intermediary between the outer drum and the product droplets. This coating layer modifies the surface properties to reduce wetting and prevent adhesion, allowing droplets to detach cleanly without requiring complex drum designs or additional cleaning mechanisms.
Solution Approach 2:
The surface energy parameters of the outer drum are changed by applying a coating with specific wetting properties. The coating is selected to have low surface energy relative to the product material, fundamentally altering the interaction between the drum surface and droplets to achieve clean detachment.
2Productivity
If the outer drum rotates at high speed to increase productivity, then output increases, but residue formation and secondary drop formation increase
Solution Approach 1:
The coating acts as a mediator that prevents direct adhesion between the product and drum surface, allowing high-speed rotation without the harmful residue formation and secondary drops that would otherwise occur at elevated speeds.
3Manufacturing precision
If a guide is added to manage residues on the outer drum, then deposition quality improves, but device complexity and cost increase
Solution Approach 1:
The need for a separate guide component is extracted and eliminated by integrating the residue prevention function directly into the drum coating. The coating itself performs the function that would otherwise require an additional mechanical guide system.
Solution Approach 2:
The coating serves as an intermediary that eliminates the need for additional guide components by directly preventing residue formation at the source, simplifying the overall device structure.
4Object-generated harmful factors
If the coating thickness is increased to improve wetting reduction, then adhesion prevention improves, but coating material consumption and manufacturing cost increase
Solution Approach 1:
The optimal coating thickness is determined by finding the parameter threshold where sufficient wetting reduction is achieved. The coating is applied at a thickness that provides the necessary surface energy modification without excessive material consumption.
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 coating enhances the quality and controlled deposition of product droplets, increasing output density and eliminating the need for a guide to manage residues, while preventing secondary drop formation and ensuring efficient product transfer.
Implementation Method 1
the coating forms a contact angle of more than 90°, in particular more than 120°, with the product to be dripped
Implementation Method 2
at least one outer circumference of the outer drum is provided with a coating which, in comparison to a base material of the outer drum, reduces wetting with the product to be dripped
Implementation Method 3
the coating is designed as a nanocoating, in particular a superhydrophobic nanocoating
Implementation Method 4
With even larger contact angles, the so-called lotus effect is also used
Implementation Method 5
A nanocoating is a coating that has a nanostructured surface with elevations and depressions in the range of less than 100 nm. Due to this surface structuring, a wetted area is also reduced due to the geometric conditions
Data Source
AI summary
A device for expelling drops of a flowable product. The invention relates to a device for expelling drops of a flowable product, comprising a rotating outer drum and a feed channel for the product to be expelled extending into the outer drum, wherein the outer drum comprises passage openings on the circumference thereof, through which the product to be expelled runs from the feed channel and then exits in droplet shape. According to the invention, at least one outer circumference of the outer drum is provided with a coating that reduces wetting with the product to be tabletted compared to a base material of the outer drum. For example, the invention can be used for tabletting flowable products.