Method and Apparatus for Producing Carbon Fiber
A carbon fiber centrifugal head includes an interior mechanism that at least partially controls flow of precursor material to exterior holes of the head during spinning.
1 . A centrifugal spinning head for producing fibers comprising:
an outer housing that forms an interior volume, the outer housing having an outer shell with a plurality of exterior apertures;
an inner screen positioned inside said interior volume and spaced from the outer shell to form a gap therebetween, the inner screen including a plurality of interior apertures; and
wherein a fiber precursor material is received in said interior volume, and upon spinning the head, flows through the interior apertures, into the gap and thereafter through the exterior apertures.
2 . The centrifugal spinning head of claim 1 further comprising a heating element positioned within the interior volume.
3 . The centrifugal spinning head of claim 1 wherein the outer shell is generally cylindrical.
4 . The centrifugal spinning head of claim 1 wherein the inner screen extends the around the entire circumference of the interior volume.
5 . The centrifugal spinning head of claim 1 wherein the ratio of the total area of the plurality of interior apertures divided by the total area of the plurality of exterior apertures is from about 0.1 to about 100.
6 . The centrifugal spinning head of claim 1 wherein the ratio of the total area of the plurality of interior apertures divided by the total area of the plurality of exterior apertures is from between about 0.5 to about 10.
7 . The centrifugal spinning head of claim 1 wherein the plurality of exterior apertures have a diameter of from about 0.5 to about 5 millimeters.
8 . The centrifugal spinning head of claim 7 wherein the plurality of exterior apertures have a diameter of from about 1 to about 2 millimeters.
9 . The centrifugal spinning head of claim 1 wherein the plurality of interior apertures have a diameter of from about 0.5 to about 5 millimeters.
10 . The centrifugal spinning head of claim 7 wherein the plurality of interior apertures have a diameter of from about 1 to about 2 millimeters.
11 . The centrifugal spinning head of claim 1 wherein the gap is from between about 0.025 mm to about 2 mm.
12 . The centrifugal spinning head of claim 11 wherein the gap is from between about 0.075 mm to about 0.5 mm.
13 . The centrifugal spinning head of claim 1 wherein substantially all of said interior apertures are unaligned with substantially all of said exterior apertures.
14 . A method of producing carbon fibers comprising:
providing a head having an outer housing that forms an interior volume and includes a plurality of exterior apertures, a screen being positioned with the interior volume, a gap being formed between the outer housing and screen;
charging fiber precursor material into the interior volume;
spinning the head;
heating the fiber precursor material to a temperature above the softening point of the fiber precursor material;
controlling the flow of the fiber precursor material out of the exterior apertures by controlling the size of the gap; and
capturing the fibers that are ejected from the exterior apertures.
15 . The method of claim 14 wherein said fiber precursor material is coal tar pitch.
16 . The method of claim 14 wherein said fiber precursor material has a QI value of from about 0 to about 50.
17 . The method of claim 16 wherein the fiber precursor material has a QI value of from about 5 to about 25 percent.
18 . The method of claim 16 wherein the head further comprises an inner screen positioned inside said interior volume and spaced from the outer shell to form a gap therebetween, the inner screen including a plurality of interior apertures.
19 . The method of claim 14 wherein the coking value of the fiber precursor material is greater than about 50%.
20 . The method of claim 19 wherein the coking value of the fiber precursor material is greater than about 70%.
21 . The method of claim 19 wherein the coking value of the fiber precursor material is greater than about 85%.
22 . The method of claim 14 further comprising stabilizing the fibers.
23 . The method of claim 22 further comprising carbonizing the fibers.