Ultrasonic Nozzle Microsphere Synthesis via Spray Pyrolysis
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Solution Overview
Problem
Current methods for forming microspheres using piezoelectric transducers are limited in producing larger sizes and are sensitive to viscosity changes, failing to effectively form droplets with higher polymer concentrations, which restricts the range of microsphere diameters and throughput.
Innovation Solution
An apparatus and method utilizing an ultrasonic nozzle to spray precursor solution droplets into a heated furnace, allowing for the formation of microspheres with a wider range of diameters and higher throughput by using precursor solutions with increased concentrations, enabling continuous production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If piezoelectric transducers are used to form droplets, then microspheres can be produced, but the microsphere size is limited to 2-30 microns and throughput is restricted
Solution Approach 1:
The patent replaces piezoelectric transducers with ultrasonic nozzles to generate droplets. The ultrasonic nozzle uses high-frequency mechanical vibrations (ultrasonic frequency) to atomize the precursor solution and form droplets, which eliminates the size limitations and sensitivity to viscosity changes associated with piezoelectric transducers. This substitution enables production of microspheres across a broader size range (2-100 microns) and at higher throughput rates.
Solution Approach 2:
The patent changes the operating parameters of the droplet generation system by using ultrasonic nozzles that can operate at different frequencies and amplitudes. This allows adjustment of droplet size and precursor solution concentration independently, enabling flexible control over microsphere diameter (2-100 microns) and throughput without the constraints imposed by piezoelectric transducer operating ranges.
2Productivity
If precursor solution concentration is increased to improve throughput, then more material can be processed, but piezoelectric transducers fail to form droplets effectively
Solution Approach 1:
The patent replaces piezoelectric transducers with ultrasonic nozzles that use high-frequency mechanical vibrations to atomize precursor solutions. This mechanical substitution enables effective droplet formation even at high precursor concentrations (up to 100 mg/ml or higher), because the ultrasonic vibrations provide sufficient energy to overcome the increased viscosity and surface tension effects that cause piezoelectric transducers to fail.
Solution Approach 2:
The patent employs ultrasonic mechanical vibration (typically 20-100 kHz frequency range) in the nozzle to generate and atomize droplets from high-concentration precursor solutions. The intense mechanical vibration creates cavitation and shear forces that reliably break up the viscous precursor solution into uniform droplets, maintaining droplet formation effectiveness even when throughput requirements demand high material concentrations.
3Productivity
If batch processes are used for microsphere production, then process control is simplified, but production throughput remains limited
Solution Approach 1:
The patent implements a continuous production process where precursor solution is continuously pumped through an ultrasonic nozzle that continuously generates droplets, which then continuously pass through a heating zone for spherification. This continuous operation eliminates the start-stop nature of batch processes, dramatically increasing throughput while maintaining process control through steady-state operating conditions. The system achieves continuous production of microspheres at rates impossible with batch methods.
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 ultrasonic nozzle system effectively produces microspheres with diameters up to 100 microns and higher concentrations, increasing throughput and enabling continuous production, surpassing the limitations of existing batch processes.
Implementation Method 1
An ultrasonic nozzle is configured to receive precursor solution and spray precursor droplets into the channel
Implementation Method 2
the heat in the channel causes the precursor droplets to form the microspheres
Implementation Method 3
MICROSPHERE SYNTHESIS VIA ULTRASONIC SPRAY PYROLYSIS
Data Source
AI summary
An apparatus, methods, and systems for forming microspheres comprises a furnace and an ultrasonic nozzle. The furnace has a channel and is operable to generate heat in the channel. The ultrasonic nozzle is configured to receive precursor solution and spray precursor droplets into the channel so that the heat in the channel causes the precursor droplets to form the microspheres.