Process for producing microspheres

Claim 2

A process for producing microspheres, which comprises the steps of: immersing a lower portion of a generally vertical sol-gel feed tube comprising a lower end portion including a generally vertical microsphere formation nozzle in a column of drying liquid of predetermined viscosity, said nozzle being hollow and having an open bottom end; feeding a sol-gel solution at a predetermined rate into an upper end portion of said feed tube and axially out said bottom end of said nozzle, said drying liquid being a nonsolvent of said sol-gel; and vibrating said nozzle at a predetermined amplitude and frequency whereby said bottom end of said nozzle is displaced over a predetermined travel in a generally horizontal direction and said sol-gel being emitted in a generally vertical direction therefrom coacts functionally with said drying liquid in a breaking action to produce formed microspheres which are uniform in size and at least partially dried in falling through said column.

Claim 3

The invention as defined in claim 1 further comprising the step of circulating said drying liquid in said column to provide an upward flow of drying liquid at a predetermined flow rate for suspending a quantity of said formed microspheres therein until an adequate drying time has elapsed.

Claim 4

The invention as defined in claim 1 wherein said feed tube comprises a lower end portion including multiple, generally vertical, microsphere formation nozzles arranged in a spaced pattern whereby vibrating said nozzles to displace them over a predetermined travel in a generally horizontal direction can produce formed microspheres from said feed tube in quantity.

Claim 5

The invention as defined in claim 3 further comprising the step of circulating said drying liquid in said column to provide an upward flow or drying liquid at a predetermined flow rate for suspending a quantity of said formed microspheres therein until an adequate drying time has elapsed.

Claim 6

A process for producing high yields of microspheres of a very uniform and predetermined size, which comprises the steps of: freely supporting a generally vertical sol-gel feed tube on one end of a connecting element, the other end of said element being connected to an electrical drive device which can be electrically energized to reciprocate said feed tube laterally at a predetermined amplitude and frequency, and said feed tube comprising a lower end portion including a generally vertical microsphere formation nozzle having a bottom end of a predetermined hollow cross sectional open area; immersing a lower portion of said feed tube in a column of drying liquid of predetermined viscosity; feeding a sol-gel solution at a predetermined rate into an upper end portion of said feed tube and axially out said bottom end of said nozzle, said drying liquid being a nonsolvent of said sol-gel; energizing said drive device with an electrical signal to reciprocate said feed tube laterally whereby said nozzle is reciprocally displaced over a predetermined travel in a generally horizontal direction and said sol-gel being emitted in a generally vertical direction from said bottom end of said nozzle coacts functionally with said drying liquid in a breaking action to produce formed microspheres therefrom of a predetermined size according to said hollow cross sectional open area of said nozzle and its horizontal reciprocation amplitude and frequency; and circulating said drying liquid in said column to provide an upward flow of drying liquid at a predetermined flow rate for suspending a quantity of said formed microspheres therein until an adequate drying time has elapsed.

Claim 7

A process for producing high yields of microspheres of a very uniform and predetermined size, which comprises the steps of: freely supporting a generally vertical sol-gel feed tube on one end of a connecting element, the other end of said element being connected to an electrical drive device which can be electrically energized to reciprocate said feed tube laterally at a predetermined amplitude and frequency, and said feed tube comprising a lower end portion including a generally vertical microsphere formation nozzle having a bottom end of a predetermined hollow cross sectional open area; immersing a lower portion of said feed tube in a column of drying liquid of predetermined viscosity; feeding a sol-gel solution at a predetermined rate into an upper end portion of said feed tube and axially out said bottom end of said nozzle, said drying liquid being a nonsolvent of said sol-gel; energizing said drive device with an electrical signal to reciprocate said feed tube laterally whereby said nozzle is reciprocally displaced over a predetermined travel in a generally horizontal direction and said sol-gel being emitted in a generally vertical direction from said bottom end of said nozzle coacts functionally with said drying liquid in a breaking action to produce formed microspheres therefrom of a predetermined size according to said hollow cross sectional open area of said nozzle and its horizontal reciprocation amplitude and frequency; and circulating said drying liquid in said column to provide an upward flow of drying liquid at a predetermined flow rate for suspending a quantity of said formed microspheres therein until an adequate drying time has elapsed.

Claim 8

The invention as defined in claim 5 wherein said drive device is responsive in reciprocation frequency according to the frequency of said electrical signal, and further comprising the step of varying said frequency of said electrical signal and hence similarly of said feed tube nozzle whereby microsphere size is essentially a function of said nozzle reciprocation frequency alone and said nozzle of the same said predetermined hollow cross sectional open area can be used without altering its reciprocation amplitude for production runs of different sizes of microspheres.

Claim 9

A process for producing high yields of microspheres of a very uniform and predetermined size, which comprises the steps of: pivotally mounting a sol-gel feed tube directly on a longitudinal pivot point in a normally vertical position, said feed tube being freely rotatable and solely supported on said pivot point, and said feed tube comprising a lower end portion including a normally vertical microsphere formation nozzle having a bottom end of a predetermined hollow cross sectional open area; immersing a lower portion of said feed tube in a column of drying liquid of predetermined viscosity; feeding a sol-gel solution at a predetermined rate into an upper end portion of said feed tube and axially out said bottom end of said nozzle, said drying liquid being a nonsolvent of said sol-gel; and oscillating a drive point directly on said feed tube above its pivot point through reciprocating drive means to oscillate said feed tube independently on said pivot point, said feed tube being thereby oscillated at a predetermined amplitude and frequency whereby said nozzle is reciprocally displaced over a predetermined travel in a generally horizontal direction, with minor travel in a generally vertical direction, and said sol-gel being emitted in a generally vertical direction from said bottom end of said nozzle coacts functionally with said drying liquid in a breaking action to produce formed microspheres therefrom of a predetermined size according to said hollow cross sectional open area of said nozzle and its horizontal reciprocation amplitude and frequency, and which are uniform in size and at least partially dried in falling through said column.

Claim 10

A process for producing high yields of microspheres of a very uniform and predetermined size, which comprises the steps of: pivotally mounting a sol-gel feed tube directly on a longitudinal pivot point in a normally vertical position, said feed tube being freely rotatable and solely supported on said pivot point, and said feed tube comprising a lower end portion including a normally vertical microsphere formation nozzle having a bottom end of a predetermined hollow cross sectional open area; immersing a lower portion of said feed tube in a column of drying liquid of predetermined viscosity; feeding a sol-gel solution at a predetermined rate into an upper end portion of said feed tube and axially out said bottom end of said nozzle, said drying liquid being a nonsolvent of said sol-gel; and oscillating a drive point directly on said feed tube above its pivot point through reciprocating drive means to oscillate said feed tube independently on said pivot point, said feed tube being thereby oscillated at a predetermined amplitude and frequency whereby said nozzle is reciprocally displaced over a predetermined travel in a generally horizontal direction, with minor travel in a generally vertical direction, and said sol-gel being emitted in a generally vertical direction from said bottom end of said nozzle coacts functionally with said drying liquid in a breaking action to produce formed microspheres therefrom of a predetermined size according to said hollow cross sectional open area of said nozzle and its horizontal reciprocation amplitude and frequency, and which are uniform in size and at least partially dried in falling through said column.

Claim 11

The invention as defined in claim 7 further comprising the step of circulating said drying liquid in said column to provide an upward flow of drying liquid at a predetermined flow rate for suspending a quantity of said formed microspheres therein until an adequate drying time has elapsed.

Claim 12

The invention as defined in claim 8 further comprising the step of varying the reciprocation frequency of said drive means and hence similarly of said feed tube nozzle whereby microsphere size is essentially a function of said nozzle reciprocation frequency alone and said nozzle of the same said predetermined hollow cross sectional open area can be used without altering its reciprocation amplitude for production runs of different sizes of microspheres.