Producing microspheres by vibrations

In an apparatus for producing spheres from a solidifiable solution, comprising:

• a dropping header for receiving the solution, a disc having at least one dropping hole for forming droplets from the solution, and a collection vessel spaced from and below the dropping header having a reactive liquid therein through which the droplets from the header fall and become solid spheres, the improvement comprising:
• means between the header and vessel connected to the header and having a chamber below each dropping hole through which the droplets fall,
• means connected to said chamber means for supplying inert gas which contacts the droplets falling through said chamber to prevent pre-hardening thereof,
• a reactive gas distributor between the header and vessel and below and parallel to the path of the droplets which fall from said chamber means for sending a stream of reactive gas onto the falling droplets for partially hardening such droplets before they fall into the collection vessel;
• and
• means connected to the vessel for providing and continuously renewing a dampening layer of foam on the reactive liquid in the vessel adapted to be penetrated by the partially hardened droplets while preventing deformation thereof as they fall and impinge upon the reactive liquid, including tube means in the vessel for removing foam at the foam/reactive liquid interface in the region where the partially hardened droplets first impinge upon the reactive liquid.