摘要:
A centrifugal pellet dryer screen (540) especially adapted for drying polymer pellets and micropellets includes an exterior or outer support screen (542), an inner screen (546) of an irregular or rough surface, and an optional middle screen(s) (544) sandwiched between the outer support screen and the inner screen. The screen layers are in intimate contact and the multi-layer screen assembly produces drier pellets and micropellets exiting the dryer. Plugging of the dryer screens and banding of the pellets or micropellets are significantly reduced.
摘要:
A process for preparing low moisture content polymer biomaterial composites and expandable polymer biomaterial composites by extrusion through a die plate into a waterbox and pelletizing with cutter blades. Polyolefins or condensation polymers are melt blended with a solid or semi-solid biomaterial component, such as polysaccharides, including cellulosics and starches, or proteinaceous materials, including polypeptides, and are extruded, pelletized underwater, and processed with accelerated drying to achieve moisture levels as low as one percent or less.
摘要:
A cutter hub and blade assembly for cutting polymer strands extruded from a die face in a pelletizer has cutter blades mounted on the cutter hub at a steep angle. The blades are beveled along a portion of their leading edge to form a blunt cutting edge or surface to the blades which is generally perpendicular to the die face. By beveling the leading edge of a blade supported at a steep angle to form a blunt cutting edge, the bottom surface area of the blade in contact with the die face can be significantly reduced. The reduced contact area provides several advantages including a clean cut of the pellets and a faster blade grinding when seating the blades to the die face.
摘要:
An apparatus and method for the pelletization of waxes, wax-like and other materials having a sharp melt point include a vessel for forming the wax into a hot molten material. A heat exchanger then cools the molten wax to a temperature just above its melt temperature. The cooled liquid wax is fed to an extruder which further reduces the temperature and mixes the liquid wax into a thoroughly mixed extrudable solid wax. The solid wax is then extruded through die orifices of a die plate into a cutting chamber, and a rotary cutter cooperating with the die face of the die plate cuts the extruded solid wax strands into pellets. The die plate, cutting chamber and rotary cutter can have the same structure as an underwater pelletizer, but operating without water or liquid as a dry face pelletizer. The thus formed wax pellets drop out of the cutting chamber by gravity through an opening in the bottom thereof.
摘要:
A melt cooler and valving system for an underwater pelletizer has a diverter valve that facilitates multiple modes of melt processing. The cooler has a cooler inlet line that conveys the melt to the cooler, and a cooler outlet line that conveys the cooled melt from the cooler. The diverter valve is configured to convey the melt to and from the cooler during a cooling mode of operation, to convey the melt around the cooler during a bypass mode of operation, and to drain the melt from the cooler and the diverter valve during a drain mode of operation. The diverter valve is compact and therefore contains a minimum of product inventory. The valve is streamlined and direct in its bypass mode, and includes a drain capability to allow for faster, easier cleaning of the process line, which in turn provides a fast changeover time with less lost product.
摘要:
A continuous process wherein polymers or polymeric materials can be subjected to multiple sequential processing systems of differing temperatures and process conditions to synergistically enhance the pelletization and conditioning of those polymers and polymeric formulations, dispersions, and solutions. The multiple sequential processing systems include the processes and equipment for mixing/extrusion, pelletization, multiple transportation processes, conditioning, multiple defluidizing processes, and optional post-processing manipulations of pellets formed. Multiple serial and/or parallel conditioning processing systems are disclosed.
摘要:
Described herein are extrusion processes to produce hollow pellets. Also disclosed are pelletizer devices that can be used to produce the hollow pellets. The processes and devices make use of an extrusion die having a die orifice and an insert that is placed in the die orifice to produce the hollow pellets.
摘要:
An underwater pelletizer providing more efficient formation of uniform size pellets including the provision of a taper on the die holes so that polymer will freeze near the exit and form an insulated die hole and a resultant cylindrical die hole for smooth polymer flow, axially movable ball bearing assemblies to support the pelletizer shaft in a housing, a threaded assembly with a thrust bearing to axially adjust the pelletizer shaft for compensating for blade wear, radial clearance for the outer race of the thrust bearing to eliminate preloading of the axially movable ball bearings, a gear coupling between the shaft and driving motor to permit axial movement of the shaft for blade adjustment, and a spring support for the pelletizer, all of which cooperate to form an effective underwater pelletizer which will efficiently produce uniform plastic pellets.
摘要:
A melt cooler and valving system for an underwater pelletizer has a diverter valve that facilitates multiple modes of melt processing. The cooler has a cooler inlet line that conveys the melt to the cooler, and a cooler outlet line that conveys the cooled melt from the cooler. The diverter valve is configured to convey the melt to and from the cooler during a cooling mode of operation, to convey the melt around the cooler during a bypass mode of operation, and to drain the melt from the cooler and the diverter valve during a drain mode of operation. The diverter valve is compact and therefore contains a minimum of product inventory. The valve is streamlined and direct in its bypass mode, and includes a drain capability to allow for faster, easier cleaning of the process line, which in turn provides a fast changeover time with less lost product.
摘要:
An apparatus and method for the pelletization of waxes, wax-like and other materials having a sharp melt point include a vessel for forming the wax into a hot molten material. A heat exchanger then cools the molten wax to a temperature just above its melt temperature. The cooled liquid wax is fed to an extruder which further reduces the temperature and mixes the liquid wax into a thoroughly mixed extrudable solid wax. The solid wax is then extruded through die orifices of a die plate into a cutting chamber, and a rotary cutter cooperating with the die face of the die plate cuts the extruded solid wax strands into pellets. The die plate, cutting chamber and rotary cutter can have the same structure as an underwater pelletizer, but operating without water or liquid as a dry face pelletizer. The thus formed wax pellets drop out of the cutting chamber by gravity through an opening in the bottom thereof.