Method and apparatus for forming glass flakes

Apparatus for forming flakes of frangible material from a heated stream of molten material capable of forming such flakes upon cooling the material to solid state, which comprises

• means for feeding the stream in a downward direction, an upwardly open cup having a top edge, means for rotating the cup, a chamber having an inlet opening, means for generating a vacuum in the chamber, and a pair of substantially parallel plates spaced apart to form a gap therebetween and correspondingly having a pair of central apertures and outer peripheries,
• the cup being rotatably arranged beneath the feeding means to receive the downward stream during rotation, and the plates being arranged with their peripheries in the chamber opening and their central apertures located about the cup to define an external air inlet thereat,
• whereby molten material within the rotating cup is caused to flow upwardly over the top edge and radially outwardly under centrifugal force, such that when a vacuum is generated in the chamber the material flowing outwardly from the cup passes through the gap between the plates, while air from outside the chamber is simultaneously drawn into the air inlet and radially outwardly in the gap between the plates to prevent the molten material from touching the plates, to cool the material until it reaches solid state, and to pull the material radially outwardly, thereby keeping the material in the form of a flat film and in turn breaking the solid state material into small platelets.

A method of forming flakes of frangible material from a heated stream of molten material, which comprises

• (a) supplying a heated stream of molten material which is capable of forming frangible flakes upon cooling from molten to solid state, in a downward direction into a cup having an open mouth defined by an edge and which faces upwardly,
• (b) simultaneously rotating the upwardly facing cup to cause the stream of molten material to flow upwardly over the edge of the cup and radially outwardly therefrom under centrifugal force,
• (c) subjecting the outwardly flowing molten material to a flow of air radially outwardly in a gap defined between a pair of substantially parallel plates to direct the flow of molten material radially outwardly between the plates without touching the plates for solidifying the molten material, the flow of air being sufficient to maintain the molten material flat and to pull the molten material radially outwardly between the plates as it solidifies, and
• (d) breaking the flat solidified material into flakes by continued subjecting of the solidified material to the flow of air radially outwardly between the plates.