A volumetric pump comprising a product metering chamber, a metering piston mounted inside the chamber so as to slide between top dead center and bottom dead center, a sleeve at least partially delimiting an intake chamber and an exhaust chamber for the product, and a product dispenser that is mounted so as to be able to move with respect to the sleeve and is able to place the metering chamber alternately into communication with the intake chamber and the exhaust chamber is provided. The pump also comprises a pressure sensor that is able to measure the pressure of the product inside the metering chamber, and a control unit that is connected to the pressure sensor and is able to verify the presence of pressure peaks exhibiting a value greater than or equal to a predetermined pressure threshold.

A mixing apparatus includes a mixer configured to mix a material including a rubber or a resin in the presence of a working fluid that is in a supercritical state or a subcritical state. The mixer includes a chamber that forms a flow passage for the working fluid and the material, and a mixing blade disposed in the chamber and fixed to the chamber.

Systems for producing superabsorbent polymer particles for use in agricultural applications are disclosed. A monomer is graft polymerized onto a starch to form a starch graft copolymer. The moisture content of the starch graft copolymer is reduced through use of an extruder.

A method of manufacturing bulked continuous carpet filament, in various embodiments, comprises: (A) providing an expanded surface area extruder; (B) providing a spinning machine having an inlet that is operatively coupled to an expanded surface area extruder outlet; (C) using a pressure regulation system to reduce the pressure within the expanded surface area extruder; (D) passing a plurality of flakes comprising recycled PET through the expanded surface area extruder to at least partially melt the plurality of flakes to form a polymer melt; and (E) substantially immediately after passing the plurality of flakes through the expanded surface area extruder, using the spinning machine to form the polymer melt into bulked continuous carpet filament. In some embodiments, the method may include passing the plurality of flakes comprising recycled PET through a PET crystallizer prior to extrusion.

A method for manufacturing bulked continuous carpet filament, the method comprising: (1) reducing a chamber pressure within a chamber to below about 5 millibars; (2) after reducing the chamber pressure to below about 5 millibars, providing a polymer melt to the chamber; (3) separating the polymer melt into at least eight streams; (4) while the at least eight streams of the polymer melt are within the chamber, exposing the at least eight streams of the polymer melt to the chamber pressure of below about 5 millibars; (5) after exposing the at least eight streams of the polymer melt to the chamber pressure of below about 5 millibars, recombining the at least eight streams into a single polymer stream; and (6) forming polymer from the single polymer stream into bulked continuous carpet filament.

An extruding system includes a melting unit configured to convey a polymeric material, a mixing unit configured to mix the polymeric material with a blowing agent to form a mixture, an injection unit configured to inject the mixture, a first flow control element disposed between the melting unit and the mixing unit, and a second flow control element disposed between the mixing unit and the injection unit. A method of extruding includes conveying a polymeric material from a melting unit to a mixing unit, conveying a blowing agent into the mixing unit, mixing the polymeric material with the blowing agent to form a mixture, conveying the mixture from the mixing unit to an injection unit, and discharging the mixture from the injection unit, wherein flow of the polymeric material is controlled by a first flow control element, and flow of the mixture is controlled by a second flow control element.

A method of operating an additive manufacturing system feeds solid extrusion material into a heater using a slip clutch coupled to an actuator of a mechanical driver to supply thermoplastic material into a manifold in an extruder head. The method sets a speed of the actuator so the actuator operates at a rotational speed that is slightly greater than the rotational speed of the mechanical mover. This method helps maintain the pressure of the thermoplastic material in the manifold of the extruder head in a predetermined range no matter how many nozzles are opened in the extruder head.

Systems for manufacturing bulked continuous carpet filament from polymer, where the systems are configured for: (1) melting polymer (e.g., derived from post-consumer PET bottles) to create a first single stream of polymer melt; (2) separating the first single stream of polymer melt into multiple streams of polymer melt; (3) exposing the multiple streams of polymer melt to a pressure of between about 0 millibars and about 5 millibars; (4) allowing the multiple streams of polymer melt to fall into a receiving section of a melt processing unit; (5) recombining the multiple streams of polymer melt into a second single stream of polymer melt; and (6) providing the second single stream of polymer melt to one or more spinning machines that are configured to form the second single stream of polymer melt into bulked continuous carpet filament.

A method of manufacturing bulked continuous carpet filament from recycled polymer. In various embodiments, the method includes: (1) reducing recycled polymer material into polymer flakes; (2) cleansing the polymer flakes; (3) melting the flakes into a polymer melt; (4) removing water and contaminants from the polymer melt by dividing the polymer melt into a plurality of polymer streams and exposing those streams to pressures below 25 millibars or another predetermined pressure; (5) recombining the streams; and (6) using the resulting purified polymer to produce bulked continuous carpet filament.

Methods for extrusion of polyolefins (112) that control specific energy input to the extruder (102) for gel reduction. Disclosed herein is an example method for forming plastic products (120, 208) with reduced gels, comprising: melting a polyolefin resin (112) in extruder (102) to form a melt; adjusting specific energy input in the extruder (102) to reduce gels in the melt; and forming the melt into a polyolefin product (120, 208). Disclosed herein is also an example method for forming plastic products (120, 20) with reduced gels, comprising: melting a polyolefin resin in extruder (102) to form a melt; selecting a throttle valve (104) position for gel reduction; setting the throttle valve (104) at the selected throttle valve (104) position to restrict flow of the melt out of the extruder (102); and forming the melt into a polyolefin product (120, 208).