The University of Texas System

Patrick Neil DuBois

John W Priest

Charles Smith

Charles Vincent Smith, Jr

Apparatus and methods for making uniformly-sized and predictably-spaced droplets or solid microspheres from high-temperature or other liquids. Liquid droplet generators having electromechanical driving elements are coupled to a power supply to apply pulsed excitation forces through a wall of a delivery tube to a liquid, e.g., a liquid metal, epoxy, or polymer. The excitation forces generated by the driver induce capillary vibrations in the liquid within the delivery tube, which breaks the stream into substantially uniformly-sized liquid droplets shortly after leaving the orifice. Droplets may be produced in a uniformly-spaced series, or individually on demand in response to a single burst of force from the driving element. If solid microspheres are desired, the trajectory of the emitted droplets is determined to permit the solidification prior to catching or collecting the microspheres. Solidification of the spherical drops may be accomplished by freezing, evaporation, or chemical reaction due to heat transfer, material transfer, or chemical reaction as the droplets traverse a controlled environment chamber. To permit collection of the microspheres with controlled material properties and without deforming or otherwise changing either the sphericity or surface quality, the flight path environment is controlled to bring the drops to a very low speed prior to collection of the solidified microspheres.

Apparatus and method for generation of microspheres of metals and other

Apparatus and methods for making uniformly-sized and predictably-spaced droplets from high-temperature liquids. Liquid droplet generators having electromechanical driving elements are coupled to a power supply to apply pulsed excitation forces through a wall of a delivery tube to a high-temperature liquid, e.g., a liquid metal, epoxy, or polymer. The excitation forces generated by the driver induce capillary vibrations in the liquid within the delivery tube. Liquid jet streams having capillary vibrations when exiting an orifice break up into groups of substantially uniformly-sized liquid droplets shortly after leaving the orifice. Droplets may be produced in a uniformly-spaced series, or individually on demand in response to a single burst of force from the driving element. A heat source is also thermally coupled to the delivery tube to maintain the liquid in a high-temperature state. Embodiments using heat-sensitive elements thermally insulate those elements from the wall of the heated delivery tube and may also actively cool the elements by one or more heat exchangers. A magnetohydrodynamic embodiment couples a magnetic field, having spaced points of maximum intensity, to a fluid stream exiting an orifice, causing the stream to break into droplets in response to the periodic magnetic field.

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Argyle, TX, United States of America

Patrick Neil DuBois