Apparatus for the extrusion of ultra high molecular weight polymeric resins

Claim 2

Apparatus for the extrusion of a continuous length of ultra high molecular weight polyethylene, said apparatus including a precompression chamber; means for delivering successive charges of particulate ultra high molecular weight polyethylene to said precompression chamber; a preheating chamber connected to said precompression chamber in axial alignment therewith, the diameter of said preheating chamber being substantially identical to that of said precompression chamber; heating means for maintaining the temperature in said preheating chamber at predetermined level; an elengated die connected to said preheating chamber in axial alignment therewith, said die having an elongated passageway provided with a tapered inlet portion adjacent one end thereof and a discharge orifice adjacent the other end thereof extending therethrough, said tapered inlet portion increasing substantially in diameter from a profile complementary to that of said elongated passageway to a size complementary to that of said preheating chamber; the transverse area relationship between the diameter of the preheating chamber and the profile of the elongated die passageway being on the order of 3:1 temperature control means extending substantially the entire length of said die for creating a predetermined maximum temperature at the die inlet for insuring the formation of a homogeneous mass and gradually reducing to a lower level as the extrusion exits from said discharge orifice; and reciprocable ram means mounted in axial alignment with said precompression chamber for successively compacting and advancing charges of particulate ultra high molecular weight polyethylene through said preheating chamber and into said die passageway.

Claim 3

APPARATUS FOR THE EXTRUSION OF A CONTINUOUS LENGTH OF ULTRA HIGH MOLECULAR WEIGHT POLYETHYLENE, SAID APPARATUS INCLUDING A PRECOMPRESSION CHAMBER; MEANS FOR DELIVERING SUCCESSIVE CHARGES OF PARTICULATE ULTRA HIGH MOLECULAR WEIGHT POLYETHYLENE TO SAID PRECOMPRESSION CHAMBER; A PREHAETING CHAMBER CONNECTED TO SAID PRECOMPRESSION CHAMBER IN AXIAL ALIGNMENT THEREWITH, THE DIAMETER OF SAID PREHEATING CHAMBER BEING SUBSTANTIALLY INDENTICAL TO THAT OF SAID PRECOMPRESSION CHAMBER; HEATING MEANS FOR MAINTAINING THE TEMPERATURE IN SAID PHEHEATING CHAMBER AT PREDETERMINED LEVEL; AN ELENGATED DIE CONNECTED TO SAID PREHEATING CHAMBER IN AXIAL ALIGNMENT THEREWITH, SAID DIE HAVING AN ELONGATED PASSAGEWAY PROVIDED WITH A TAPERED INLET PROTION ADJACENT ONE END THEREOF AND DISCHARGE ORIFICE ADJACENT THE OTHER END THEREOF EXTENDING THERETHROUGH, SAID TAPERED INLET PORTION INCREASING SUBSTANTIALLY IN DIAMETER FROM A PROFILE COMPLEMENTAARY TO THAT OF SAID

Claim 4

APPARATUS FOR THE EXTRUSION OF A CONTINUOUS LENGTH OF ULTRA HIGH MOLECULAR WEIGHT POLYETHYLENE, SAID APPARATUS INCLUDING A PRECOMPRESSION CHAMBER; MEANS FOR DELIVERING SUCCESSIVE CHARGES OF PARTICULATE ULTRA HIGH MOLECULAR WEIGHT POLYETHYLENE TO SAID PRECOMPRESSION CHAMBER; A PREHAETING CHAMBER CONNECTED TO SAID PRECOMPRESSION CHAMBER IN AXIAL ALIGNMENT THEREWITH, THE DIAMETER OF SAID PREHEATING CHAMBER BEING SUBSTANTIALLY INDENTICAL TO THAT OF SAID PRECOMPRESSION CHAMBER; HEATING MEANS FOR MAINTAINING THE TEMPERATURE IN SAID PHEHEATING CHAMBER AT PREDETERMINED LEVEL; AN ELENGATED DIE CONNECTED TO SAID PREHEATING CHAMBER IN AXIAL ALIGNMENT THEREWITH, SAID DIE HAVING AN ELONGATED PASSAGEWAY PROVIDED WITH A TAPERED INLET PROTION ADJACENT ONE END THEREOF AND DISCHARGE ORIFICE ADJACENT THE OTHER END THEREOF EXTENDING THERETHROUGH, SAID TAPERED INLET PORTION INCREASING SUBSTANTIALLY IN DIAMETER FROM A PROFILE COMPLEMENTAARY TO THAT OF SAID

Claim 5

Extrusion apparatus as set forth in claim 1, where longitudinally extending spreader means is mounted within the preheating chamber to insure the complete homogenization of the particulate thermoplastic material as it is advanced through said preheating chamber.

Claim 6

Extrusion apparatus as set forth in claim 2 where said spreader means is constituted by at least one pair of diametrically disposed and relatively thin elongated blades, the leading edge of each blade being provided with a relatively sharp edge so as to split the moving stream of extrudate.

Claim 7

Extrusion apparatus as set forth in claim 1 where the temperature of the preheating chamber is maintained at a temperature on the order of 420*F.

Claim 8

Extrusion apparatus as set forth in claim 1 where the temperature of the die at the inlet end thereof is on the order of 420*F., the temperature in the die passageway is decreased gradually to 250*F., and the temperature of the die passageway is further decreased to 200*F. at the die orifice.

Claim 9

Apparatus for the extrusion of a continuous length of ultra high molecular weight thermoplastic material having a molecular weight of 2.5 million to 4.0 million, said apparatus including a first cylindrical member having a centrally located axial bore extending therethrough providing a precompression chamber, the upper surface of said first cylindrical member being provided with a vertically disposed passage providing communication with said precompression chamber adjacent the inlet extremity thereof whereby particles of ultra high molecular weight thermoplastic material may be delivered to said precompression chamber in metered quantities; and integral annular boss on the outer verical face of said first cylindrical member in surrounding relationship with respect to the outlet extremity of said precompression chamber; a second cylindrical member mounted in abutting relationship with respect to the outer face of said first cylindrical member, the adjacent face of said second cylindrical member being prorvided with a complementarily conformed annular recess for the reception of said annular boss and insuring axial alignment between said first and second cylindrical members; said second cylindrical member also being proovided with a centrally located axial bore extending therEthrough providing a preheating chamber, the diameter of said preheating chamber being identical to that of said precompression chamber; heating means surrounding said second cylindrical member and extending the length thereof for maintaining the temperature in said preheating chamber at a predetermined level; an elongated die connected to said preheating chamber in axial alignment therewith, said die including an enlarged annular flange on the inner extremity thereof, said flange being provided with a centrally located annular recess for the reception of the outer extremity of said second cylindrical member, said die having an elongated passageway provided with a tapered inlet portion adjacent one end thereof and a discharge orifice adjacent the other end thereof extending therethrough, said tapered inlet portion increasing substantially in diameter from a profile complementary to that of said elongted passageway to a size complementary to that of said preheating chamber; the transverse area relationship between the diameter of the preheating chamber and the profile of the elongated die passageway being on the order of 3:1, temperature control means extending substantially the entire length of said die for creating a predetermined maximum temperatue at the die inlet for insuring the formation of a homogeneous mass and gradually reducing to a lower level as the extrusion exits from the die orifice; and reciprocable ram means mounted in axial alignment with said precompression chamber for successively compacting and advancing charges of particulate ultra high molecular weight thermoplastic material through said preheating chamber and into the die passageway.

Claim 10

Apparatus for the extrusion of a continuous length of ultra high molecular weight thermoplastic material having a molecular weight of 2.5 million to 4.0 million, said apparatus including a first cylindrical member having a centrally located axial bore extending therethrough providing a precompression chamber, the upper surface of said first cylindrical member being provided with a vertically disposed passage providing communication with said precompression chamber adjacent the inlet extremity thereof whereby particles of ultra high molecular weight thermoplastic material may be delivered to said precompression chamber in metered quantities; and integral annular boss on the outer verical face of said first cylindrical member in surrounding relationship with respect to the outlet extremity of said precompression chamber; a second cylindrical member mounted in abutting relationship with respect to the outer face of said first cylindrical member, the adjacent face of said second cylindrical member being prorvided with a complementarily conformed annular recess for the reception of said annular boss and insuring axial alignment between said first and second cylindrical members; said second cylindrical member also being proovided with a centrally located axial bore extending therEthrough providing a preheating chamber, the diameter of said preheating chamber being identical to that of said precompression chamber; heating means surrounding said second cylindrical member and extending the length thereof for maintaining the temperature in said preheating chamber at a predetermined level; an elongated die connected to said preheating chamber in axial alignment therewith, said die including an enlarged annular flange on the inner extremity thereof, said flange being provided with a centrally located annular recess for the reception of the outer extremity of said second cylindrical member, said die having an elongated passageway provided with a tapered inlet portion adjacent one end thereof and a discharge orifice adjacent the other end thereof extending therethrough, said tapered inlet portion increasing substantially in diameter from a profile complementary to that of said elongted passageway to a size complementary to that of said preheating chamber; the transverse area relationship between the diameter of the preheating chamber and the profile of the elongated die passageway being on the order of 3:1, temperature control means extending substantially the entire length of said die for creating a predetermined maximum temperatue at the die inlet for insuring the formation of a homogeneous mass and gradually reducing to a lower level as the extrusion exits from the die orifice; and reciprocable ram means mounted in axial alignment with said precompression chamber for successively compacting and advancing charges of particulate ultra high molecular weight thermoplastic material through said preheating chamber and into the die passageway.