A method of forming hollow glass spheres S shaped by the effects of surface tension acting on bubbles of glass in its molten state; the method is characterized by the steps of establishing a downwardly flowing stream of air accelerated at a one-G rate of acceleration through a drop tower 10, introducing into the stream of air free-falling bubbles B of molten glass, and freezing the bubbles in the stream as they are accelerated at a one-G rate of acceleration.
A sonic levitation apparatus (A) is disclosed which includes a sonic transducer (14) which generates acoustical energy responsive to the level of an electrical amplifier (16). A duct (B) communicates with an acoustical chamber (18) to deliver an oscillatory motion of air to a plenum section (C) which contains a collimated hole structure (D) having a plurality of parallel orifices (10). The collimated hole structure converts the motion of the air to a pulsed, unidirectional stream providing enough force to levitate a material specimen (S).
A method for obtaining urea prills in a prilling tower (1) comprising the step of making a plurality of melt urea droplets to fall from a urea melt distributing device (4) towards an urea prills collecting bottom (6) of the prilling tower, further comprises the step of cooling the collecting bottom (6).
A method and apparatus for preparing and studying samples of materials supercooled and solidified in a containerless, low-gravity environment in bulk form is disclosed which includes an enclosure 10 in which a containerless environment is provided in which a sample specimen 52 is positioned. Method contemplates heating the specimen 52 in the containerless environment, dropping the specimen melt through the tube 12 wherein it cools by radiation, and alternately backfilling the tube 12 with an inert gas whereby the specimen melt cools by both radiation and convection during its free fall. During the free fall, the sample is in a containerless, low-gravity environment which will enhance supercooling in the sample and prevent sedimentation and thermal convection influences. The sample will continue to supercool until nucleation occurs which is detected by silicon photovoltaic detectors. The sample will solidify after nucleation and be completely solid before entering the detachable catcher. The amount of supercooling of the specimen can be measured by knowing the cooling ratio and determining the time for nucleation to occur.
A process of manufacturing vitreous beads in which particulate feedstock is delivered to a heated chamber and passed along it so that the feedstock is heated and converted to vitreous beads whereafter the beads are collected, characterised in that the chamber is shaped to provide a flow path for the particles which is of elongate cross-section and is arranged so that the particles pass downwardly through it under gravity, and in that the particles passing through the chamber are heated by radiant heating means which emanates from the chamber walls.
A spherulizing furnace for manufacturing vitreous beads, including a chamber; means for heating the chamber; feed means for delivering a particulate feedstock to one end of the chamber; and means for collecting vitreous beads from another end of the chamber, wherein the chamber includes a pair of opposed walls which are spaced apart by a distance less than their breadth and which are angled to the horizontal so that the chamber has an upper end and a lower end, the feed means is arranged to deliver feedstock to the upper end of the chamber so that the feedstock can pass through the chamber under gravity, and the means for heating the chamber is arranged to heat at least one wall of the pair of opposed walls so that feedstock passing between the pair of opposed walls is heated by radiant heat.
