Indirect Acoustic Drying System Preventing Coating Skin Formation
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Solution Overview
Problem
Conventional heating and drying methods, especially those using ultrasonic waves and heat, can damage coatings or substrates by forming surface skins that impede moisture or solvent evaporation, leading to slower drying processes and potential defects like cracks or blisters.
Innovation Solution
An acoustic drying system that uses ultrasonic transducers positioned to direct acoustic energy through the substrate rather than directly at the coating, enhancing thermal and mass transfer while maintaining the coating on the substrate, and includes an air delivery enclosure to direct acoustic air towards the substrate, preventing surface skin formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If acoustic energy is directed directly at the coating surface to accelerate drying, then drying rate is improved, but surface skin formation and coating damage occur
Solution Approach 1:
The patent uses the substrate as an intermediary medium to transmit acoustic energy from the transducer to the coating layer. The ultrasonic transducer is positioned against the substrate and transmits acoustic waves through it, allowing energy delivery to the coating without direct exposure to the coating surface, thereby preventing skin formation while maintaining effective drying acceleration
Solution Approach 2:
Instead of directing acoustic energy from the coating side (which causes surface damage), the patent inverts the approach by positioning the ultrasonic transducer on the opposite side of the substrate and transmitting energy through the substrate to reach the coating. This reverse configuration eliminates direct surface exposure to high-intensity acoustic waves while still achieving the desired drying effect
2Productivity
If high intensity acoustic waves are applied to the coating surface, then evaporation rate is improved, but coating cracks and substrate damage occur
Solution Approach 1:
The substrate serves as a mediator that distributes and attenuates the acoustic energy before it reaches the coating. By transmitting ultrasonic waves through the substrate rather than directly at the coating, the energy is delivered more uniformly and with reduced peak intensity, preventing coating cracking while maintaining effective evaporation acceleration
Solution Approach 2:
The patent changes the physical parameters of energy delivery by transmitting acoustic waves through a different medium (the substrate) rather than directly through air to the coating. This modification in the transmission path alters the energy distribution pattern, reducing localized high-intensity regions that cause coating damage while maintaining overall evaporation effectiveness
3Productivity
If acoustic transducer is positioned close to the coating surface, then drying efficiency is improved, but surface damage and skin formation increase
Solution Approach 1:
The patent inverts the conventional positioning by placing the ultrasonic transducer on the opposite side of the substrate from the coating, rather than close to the coating surface. This inversion allows the transducer to be positioned close to the substrate without risking coating damage, as the substrate acts as a protective barrier that prevents direct acoustic exposure to the coating
Solution Approach 2:
The substrate functions as an intermediary layer between the transducer and the coating, enabling close positioning of the transducer to the substrate while preventing direct acoustic energy exposure to the coating. This intermediary arrangement maintains high drying efficiency through effective energy transmission while eliminating surface damage risks
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 method effectively accelerates the drying process without damaging the coating or substrate, ensuring complete evaporation and preventing residual moisture issues that could lead to defects, thereby improving the quality and efficiency of the drying process.
Implementation Method 1
an ultrasonic transducer positioned at least partly inside a bottom portion of the air delivery enclosure, the ultrasonic transducer facing the material... acoustic energy is conducted through the substrate to enhance thermal and mass transfer
Implementation Method 2
passing air through the ultrasonic transducer to generate acoustic waves... acoustic air is directed to the first side of the material and that acoustic energy is conducted through the substrate
Implementation Method 3
the properties of the boundary layer formed next to the surface along which a fluid moves dictate the heat transfer rate at the surface... heat transfer rates are higher for turbulent flow at a surface than for laminar flow at that surface
Implementation Method 4
there are several methods to disrupt the boundary layer in order to produce more turbulent flow and therefore more heat transfer
Implementation Method 5
the resulting water or solvent evaporation rates are factors in the outcome of any drying and/or heating process... complete evaporation and preventing residual moisture issues
Data Source
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AI summary
Disclosed is an acoustic head for indirectly drying a material, the acoustic head including at least one ultrasonic transducer facing the material, the material having a first side, and a second side, the second side opposite the first side, the second side defining a surface to be dried, the ultrasonic transducer positioned facing the first side; and an air delivery unit positioned facing the first side of the material.