Particulate metal filter medium for polymer melts

Claim 2

A particulate filter medium for polymer melts comprising: irregularly shaped, rough surfaced particles having a composite shape factor less than 0.58, said particles being formed from a metal alloy, said alloy consisting essentially of about 30 percent to about 40 percent by weight chromium; about 2 percent to about 4 percent by weight silicon; 100 to 400 parts per million by weight carbon and 600 to 1,000 parts per million by weight nitrogen; and the remainder iron.

Claim 3

The particulate filter medium of claim 1, said alloy consisting essentially of about 35 percent by weight chromium; about 3 percent by weight silicon; about 310 parts per million by weight carbon; about 740 parts per million by weight nitrogen; and the remainder iron.

Claim 4

IN A SPINNING PACK ASSEMBLY INCLUDING A FILTER BODY THROUGH WHICH POLYMER FLOWS FROM A PRESSURIZED SOURCE TO A SPINNERET FOR FORMING FILAMENTS, THE IMPROVEMENT COMPRISING: SAID BODY CONTAINING A BED OF IRREGULARLY SHAPED ROUGH SURFACED METAL PARTICLES HAVING A SHAPE FACTOR OF LESS THAN ABOUT 00.58, SAID BED BEING CHARACTERIZED BY A POROSITY OF AT LEAST 60 PERCENT UNDER NO APLIED LOAD AND BY COMPACTION OF NO MORE THAN ABOUT 20 PERCENT OR ABOUT 30 PERCENT UNDER APPLIED LOADS OF ABOUT 5,000 POUNDS PER SQUARE INCH OR 10,000 POUNDS PER SQUARE INCH RESPECTIVELY, SAID METAL PARTICLES BEING FORMED FROM AN ALLOY, SAID ALLOY CONSISTING ESSENTIALLY OF ABOUT 30 PERCENT TO ABOUT 40 PERCENT BY WEIGHT CHROMIUM, ABOUT 2 PERCENT TO ABOUT 4 PERCENT BY WEIGHT SILICON, 100 TO 400 PARTS PER MILLION BY WEIGHT CARBON, 600 TO 1,000 PARTS PER MILLION BY WEIGHT NITROGEN, AND THE REMAINDER IRON.

Claim 5

IN A SPINNING PACK ASSEMBLY INCLUDING A FILTER BODY THROUGH WHICH POLYMER FLOWS FROM A PRESSURIZED SOURCE TO A SPINNERET FOR FORMING FILAMENTS, THE IMPROVEMENT COMPRISING: SAID BODY CONTAINING A BED OF IRREGULARLY SHAPED ROUGH SURFACED METAL PARTICLES HAVING A SHAPE FACTOR OF LESS THAN ABOUT 00.58, SAID BED BEING CHARACTERIZED BY A POROSITY OF AT LEAST 60 PERCENT UNDER NO APLIED LOAD AND BY COMPACTION OF NO MORE THAN ABOUT 20 PERCENT OR ABOUT 30 PERCENT UNDER APPLIED LOADS OF ABOUT 5,000 POUNDS PER SQUARE INCH OR 10,000 POUNDS PER SQUARE INCH RESPECTIVELY, SAID METAL PARTICLES BEING FORMED FROM AN ALLOY, SAID ALLOY CONSISTING ESSENTIALLY OF ABOUT 30 PERCENT TO ABOUT 40 PERCENT BY WEIGHT CHROMIUM, ABOUT 2 PERCENT TO ABOUT 4 PERCENT BY WEIGHT SILICON, 100 TO 400 PARTS PER MILLION BY WEIGHT CARBON, 600 TO 1,000 PARTS PER MILLION BY WEIGHT NITROGEN, AND THE REMAINDER IRON.

Claim 6

The assembly as defined in claim 3, said alloy consisting essentially of about 35 percent by weight chromium; about 3 percent by weight silicon; about 310 parts per million by weight carbon; about 740 parts per million by weight nitrogen; and the remainder iron.