Waste recovery of thermoplastic continuous filamentary material

Claim 2

Apparatus for recovering waste thermoplastic fiber of continuous length filamentary material and converting it into reuseable feedstock, and comprising: means for converting said continuous length filamentary material into staple fiber; storage means for receiving and storing said staple fiber; conveyor means for moving said staple fiber to said storage means from said means for converting said continuous length filamentary material; said storage means having an inlet through which the staple fiber is received and an outlet through which the staple fiber leaves the storage means, a conveyor means within the storage means for moving the staple fiber from the inlet to the outlet; an extruder for compacting and melting said staple fiber; conveyor means for delivering said staple fiber to said extruder from said storage means; said extruder having at one end a feed section adapted to receive said staple fiber and a feed screw that extends the length of the extruder and feed section; said feed section defining an elongated tangential side opening through which said staple fiber is introduced, and having a downwardly inclined surface that extends from said tangential side opening and to a location tangentially adjacent said feed screw and adapted to conduct said staple fiber into the bite of the feed screw as defined therebetween by the downwardly turning portion of the feed screw and said downwardly inclined surfaCe; said feed section further being jacketed and thereby adapted to be cooled by a circulating fluid medium so that the feed section interior wall surface with which the staple fiber comes into contact is below the temperature at which the staple fiber would tend to stick to said interior wall surface; said feed section still further having a plurality of keyed wedges extending radially inwardly from the interior wall surface of the feed section and circumferentially spaced apart and spaced from said feed screw, said keyed wedges initially spiralling partly around and along a portion of the length of the feed section and then straightening out to extend parallel to and for the remainder of said length of the feed section, the keyed wedges adapted to cooperate with said feed screw to prevent said staple fiber from rotating with said feed screw and to assure continuous forward feeding of the staple fiber from the tangential side opening; said extruder having heating means extending along the length of the extruder forward of the feed section for melting said staple fiber into a melt flow and means for forcing cooling air around the outside of the extruder so as to regulate the heat applied to the staple fiber; extrusion die means comprising an underwater pelletizer defining an inlet for receiving said melt flow, a die through which the melt flow is extruded, means for circulating a heated fluid through said die to maintain a predetermined temperature, means for circulating a cooling fluid on the extrusion side of the die to cool the melt flow when extruded through the die, shearing means for shearing melt flow into pellets when the melt flow is extruded through the die, and outlet means adapted to conduct therethrough the extruded pellets and cooling liquid as a liquid slurry; means connecting the extruder and the extrusion die means and adapted to conduct said melt flow from one to the other; and means following the underwater pelletizer and adapted to receive said liquid slurry from said outlet means and remove the liquid from and dry said pellets.

Claim 3

Apparatus for recovering waste thermoplastic fiber of continuous length filamentary material and converting it into re-useable feedstock, and comprising: means for converting said continuous length filamentary material into staple fiber; storage means for receiving and storing said staple fiber; conveyor means for moving said staple fiber to said storage means from said means for converting said continuous length filamentary material; said storage means having an inlet through which the staple fiber is received and an outlet through which the staple fiber leaves the storage means, a conveyor means within the storage means for moving the staple fiber from the inlet to the outlet; an extruder for compacting and melting said staple fiber; conveyor means for delivering said staple fiber to said extruder from said storage means; said extruder having at one end a feed section adapted to receive said staple fiber and a feed screw that extends the length of the extruder and feed section; said feed section defining an elongated tangential side opening through which said staple fiber is introduced, and having a downwardly inclined surface that extends from said tangential side opening and to a location tangentially adjacent said feed screw and adapted to conduct said staple fiber into the bite of the feed screw as defined therebetween by the downwardly turning portion of the feed screw and said downwardly inclined surfaCe; said feed section further being jacketed and thereby adapted to be cooled by a circulating fluid medium so that the feed section interior wall surface with which the staple fiber comes into contact is below the temperature at which the staple fiber would tend to stick to said interior wall surface; said feed section still further having a plurality of keyed wedges extending radially inwardly from the interior wall surface of the feed section and circumferentially spaced apart and spaced from said feed screw, said keyed wedges initially spiralling partly around and along a portion of the length of the feed section and then straightening out to extend parallel to and for the remainder of said length of the feed section, the keyed wedges adapted to cooperate with said feed screw to prevent said staple fiber from rotating with said feed screw and to assure continuous forward feeding of the staple fiber from the tangential side opening; said extruder having heating means extending along the length of the extruder forward of the feed section for melting said staple fiber into a melt flow and means for forcing cooling air around the outside of the extruder so as to regulate the heat applied to the staple fiber; extrusion die means comprising an underwater pelletizer defining an inlet for receiving said melt flow, a die through which the melt flow is extruded, means for circulating a heated fluid through said die to maintain a predetermined temperature, means for circulating a cooling fluid on the extrusion side of the die to cool the melt flow when extruded through the die, shearing means for shearing melt flow into pellets when the melt flow is extruded through the die, and outlet means adapted to conduct therethrough the extruded pellets and cooling liquid as a liquid slurry; means connecting the extruder and the extrusion die means and adapted to conduct said melt flow from one to the other; and means following the underwater pelletizer and adapted to receive said liquid slurry from said outlet means and remove the liquid from and dry said pellets.

Claim 4

Apparatus for recovering waste thermoplastic fiber of continuous length filamentary material and converting it into re-useable feedstock, and comprising: means for converting said continuous length filamentary material into staple fiber; storage means for receiving and storing said staple fiber; conveyor means for moving said staple fiber to said storage means from said means for converting said continuous length filamentary material; said storage means having an inlet through which the staple fiber is received and an outlet through which the staple fiber leaves the storage means, a conveyor means within the storage means for moving the staple fiber from the inlet to the outlet; an extruder for compacting and melting said staple fiber; conveyor means for delivering said staple fiber to said extruder from said storage means; said extruder having at one end a feed section adapted to receive said staple fiber and a feed screw that extends the length of the extruder and feed section; said feed section defining an elongated tangential side opening through which said staple fiber is introduced, and having a downwardly inclined surface that extends from said tangential side opening and to a location tangentially adjacent said feed screw and adapted to conduct said staple fiber into the bite of the feed screw as defined therebetween by the downwardly turning portion of the feed screw and said downwardly inclined surfaCe; said feed section further being jacketed and thereby adapted to be cooled by a circulating fluid medium so that the feed section interior wall surface with which the staple fiber comes into contact is below the temperature at which the staple fiber would tend to stick to said interior wall surface; said feed section still further having a plurality of keyed wedges extending radially inwardly from the interior wall surface of the feed section and circumferentially spaced apart and spaced from said feed screw, said keyed wedges initially spiralling partly around and along a portion of the length of the feed section and then straightening out to extend parallel to and for the remainder of said length of the feed section, the keyed wedges adapted to cooperate with said feed screw to prevent said staple fiber from rotating with said feed screw and to assure continuous forward feeding of the staple fiber from the tangential side opening; said extruder having heating means extending along the length of the extruder forward of the feed section for melting said staple fiber into a melt flow and means for forcing cooling air around the outside of the extruder so as to regulate the heat applied to the staple fiber; extrusion die means comprising an underwater pelletizer defining an inlet for receiving said melt flow, a die through which the melt flow is extruded, means for circulating a heated fluid through said die to maintain a predetermined temperature, means for circulating a cooling fluid on the extrusion side of the die to cool the melt flow when extruded through the die, shearing means for shearing melt flow into pellets when the melt flow is extruded through the die, and outlet means adapted to conduct therethrough the extruded pellets and cooling liquid as a liquid slurry; means connecting the extruder and the extrusion die means and adapted to conduct said melt flow from one to the other; and means following the underwater pelletizer and adapted to receive said liquid slurry from said outlet means and remove the liquid from and dry said pellets.

Claim 5

Apparatus for recovering an entangled mass of waste thermoplastic fiber of continuous length filamentary material and converting it into re-usable feed stock, and comprising: means for compressing said entangled mass of continuous length filamentary material into a mass of predetermined size; means for cutting said mass of predetermined size into sections of predetermined size, and further means for cutting said sections into staple fiber; extruder means for mechanically compacting and melting said staple fiber into a melt flow, and extruding said melt flow into said re-useable feedstock; said extruder means having a barrel and a feed screw rotatable within said barrel, said barrel having connected at one end an extrusion die means and at the other end including a feed section, and being provided with heating means along its length; said feed section defining an elongated tangential side opening through which said staple fiber is introduced into the bite of the feed screw, as defined therebetween by the downwardly turning portion of the feed screw and the interior wall of the barrel; and means for feeding said staple fiber to and into said tangential side opening and into the bite of the feed screw thereby entrapping the staple fiber on the underside of the feed screw and including means for controlling and metering the feed of said staple fiber; said feed section further including therewithin means for preventing said staple fiber from rotating with said feed screw and thereby adapted to enable and assure continuous forward movement of the staple fiber from the feed section to said extrusion die means.

Claim 6

Apparatus for recovering an entangled mass of waste thermoplastic fiber of continuous length filamentary material and converting it into re-usable feed stock, and comprising: means for compressing said entangled mass of continuous length filamentary material into a mass of predetermined size; means for cutting said mass of predetermined size into sections of predetermined size, and further means for cutting said sections into staple fiber; extruder means for mechanically compacting and melting said staple fiber into a melt flow, and extruding said melt flow into said re-useable feedstock; said extruder means having a barrel and a feed screw rotatable within said barrel, said barrel having connected at one end an extrusion die means and at the other end including a feed section, and being provided with heating means along its length; said feed section defining an elongated tangential side opening through which said staple fiber is introduced into the bite of the feed screw, as defined therebetween by the downwardly turning portion of the feed screw and the interior wall of the barrel; and means for feeding said staple fiber to and into said tangential side opening and into the bite of the feed screw thereby entrapping the staple fiber on the underside of the feed screw and including means for controlling and metering the feed of said staple fiber; said feed section further including therewithin means for preventing said staple fiber from rotating with said feed screw and thereby adapted to enable and assure continuous forward movement of the staple fiber from the feed section to said extrusion die means.

Claim 7

Apparatus according to claim 2, and wherein the extruder means further comprises: means for internally cooling said feed section of the barrel so that the feed section interior wall surface with which the staple fiber comes into contact is below the tEmperature at which the staple fiber would tend to stick to said feed section interior wall surface.

Claim 8

Apparatus according to claim 2 and wherein said extrusion die means comprises an underwater pelletizer including a die, means located on one side of the die to heat the die, and means on the other side of the die to circulate heated water against the face of the die.

Claim 9

Apparatus according to claim 2 and wherein said means for controlling and metering the feed of said staple fiber includes a storage bin adapted to receive and store more staple fiber than can be fed directly to said extruder means for mechanically compacting and melting said staple fiber, said storage bin having inlet and outlet openings through which the staple fiber moves, and including therewithin conveyor means for moving the stored fiber from the inlet opening to the outlet opening and means for controlling the amount of staple fiber that moves through said outlet means.

Claim 10

Apparatus according to claim 2 and wherein said means for preventing said staple fiber from rotating includes surfaces extending radially inwardly from the interior wall of the feed section and being circumferentially spaced apart and adapted to cooperate with the flights on said feed screw to keep the movement of the mass of staple fibers perpendicular to the screw flights.

Claim 11

Apparatus according to claim 2 and wherein said means for preventing said staple fiber from rotating includes a keyed section extending radially inwardly from the interior wall surface of the barrel and spaced from said feed screw, said keyed section initially spiralling partly around and along a portion of the length of the feed section and then straightening out to extend parallel to and for the remainder of said length of the feed section.

Claim 12

Apparatus according to claim 2 and wherein said means for preventing said staple fiber from rotating includes a plurality of keyed wedges extending radially inwardly from the interior wall surface of said feed section and circumferentially spaced apart and spaced from said feed screw, said keyed wedges each initially spiralling partly around and along a portion of the length of the feed section and then straightening out to extend parallel to and for the remainder of said length of the feed section.

Claim 13

Apparatus according to claim 7 and wherein said feed screw has substantially coextensive with said tangential side opening a first section having a root diameter of constant size, the interior wall surface adjacent to said first section and to said side opening tapering inwardly toward said feed screw and thereby adapted in cooperation with said feed screw to initiate compression of said staple fiber.

Claim 14

Apparatus according to claim 7 and wherein a downwardly inclined surface extends from said elongated tangential side opening toward said bite of the feed screw, said inclined surface adapted to conduct said staple fiber into said bite when the fiber is introduced into said side opening.

Claim 15

Apparatus according to claim 2 and wherein said tangential side opening has a length about three times the diameter of the feed screw.