Abstract: An apparatus and method for extruding, cooling and cutting an extrusion using temperature feedback can include an extruder for producing an extrudate which can be fed through appropriate sizing, support and cooling devices, which can include one or more of a vacuum chamber, cooling chamber, and calibrators having internal cooling passages. The apparatus can also include a cutting blade, a programmable temperature controller for controlling the cooling of the extrudate based upon feedback on the temperature of the extrudate sensed near the cutting blade and/or prior to a device which feeds the extrusion through the system. The method can include sensing the temperature of the extrudate, at a point near the cutting blade and/or prior to the feed device, subsequent to extrusion being passed through the sizing, support and/or cooling devices.

Abstract: A centrifugal pellet dryer apparatus, lifter and rotor wherein the lifters can have a surface configured to deflect pellets inwardly and the rotor can have lifters attached in an arrangement designed to increase pellet impacts with lifters by providing a higher concentration of lifters on the rotor in a first region which initially engages a slurry of pellets and water. The inwardly curved lifters tend to direct the pellets inwards toward other lifters and away from dewatering screens and the higher concentration of lifters on the lower region of the rotor results in added pellet impacts with lifters. The centrifugal pellet dryer can have an outer housing, a base portion with a water discharge outlet and a top portion having a pellet discharge port and an exhaust port. Within the housing can be one or more generally cylindrical foraminous members disposed around the rotor. One or more separator plates can be provided between the foraminous members to divide the pellet dryer into sections.

Abstract: An apparatus and method for extruding, cooling and cutting can include an extruder for producing an extrudate which can be fed through appropriate sizing, support and cooling devices, which can include a vacuum chamber, cooling chamber, and calibrators, which can have internal cooling passageways. The apparatus can also include a cutting blade, a programmable temperature controller for controlling the temperature of the extrudate prior to being cut by the cutting blade, and a temperature sensor, which can be positioned near the cutting blade and provide feedback to the temperature controller. The method can include sensing the temperature of the extrudate, at a point near the cutting blade, after it is fed through the sizing, support and cooling devices and before being cut. Such feedback can be used to control the temperature of the extrudate such that the extrudate is maintained within a desired range of temperature as it is cut.

Abstract: A centrifugal pellet dryer apparatus, lifter and rotor wherein the lifters can have a surface configured to deflect pellets inwardly and the rotor can have lifters attached in an arrangement designed to increase pellet impacts with lifters by providing a higher concentration of lifters on the rotor in a first region which initially engages a slurry of pellets and water. The inwardly curved lifters tend to direct the pellets inwards toward other lifters and away from dewatering screens and the higher concentration of lifters on the lower region of the rotor results in added pellet impacts with lifters. The centrifugal pellet dryer can have an outer housing, a base portion with a water discharge outlet and a top portion having a pellet discharge port and an exhaust port. Within the housing can be one or more generally cylindrical foraminous members disposed around the rotor. One or more separator plates can be provided between the foraminous members to divide the pellet dryer into sections.

Abstract: A centrifugal pellet dryer apparatus, lifter and rotor wherein the lifters can have a surface configured to deflect pellets inwardly and the rotor can have lifters attached in an arrangement designed to increase pellet impacts with lifters by providing a higher concentration of lifters on the rotor in a first region which initially engages a slurry of pellets and water. The inwardly curved lifters tend to direct the pellets inwards toward other lifters and away from dewatering screens and the higher concentration of lifters on the lower region of the rotor results in added pellet impacts with lifters. The centrifugal pellet dryer can have an outer housing, a base portion with a water discharge outlet and a top portion having a pellet discharge port and an exhaust port. Within the housing can be one or more generally cylindrical foraminous members disposed around the rotor. One or more separator plates can be provided between the foraminous members to divide the pellet dryer into sections.

Abstract: A method and apparatus for using vaporized liquid cryogen to cool articles, particularly extrusions, utilizing dispersion of liquid cryogen into a chamber wherein it is substantially vaporized and then circulated through cooling circuits in a tool for cooling the tool, or an article such as an extrusion which is to be cooled by the tool. Additionally, the tool may itself be disposed in a cooling chamber in which vaporized cryogen is circulated to cool the tool and the article.

Abstract: A rotary knife cutter is provided. The rotary knife cutter has a flywheel to which knife blades are attached at the circumference of the flywheel. The flywheel is directly driven by a gear reducer that is directly connected to a servo-motor. The servo-motor may be operated to rotate the flywheel at a constant speed for cutting or the servo-motor may cause the flywheel to stop after each revolution to regulate the cutting desired. One or more blades may be attached to the flywheel depending upon the desired type of cuts to be made. Cutter bushings varying in size and cross-sectional shape may be utilized to guide a particular cross-sectional size and shape of material to the cutter knives.

Abstract: A dispensing apparatus dispenses a precisely metered quantity of pellets or granular material from a hopper to a vessel. The hopper which holds the pellets or granular material has a conical bottom portion which terminates in a bottom opening that is in constant communication with a conveyor tube which leads to the vessel. The conveyor tube preferably extends horizontally below the hopper and is in communication with a bottom opening in the hopper. A venturi driven by compressed air is provided in the conveyor tube for creating a vacuum which carries the pellets or granular material from the hopper to the vessel. The pressure of the compressed air entering the venturi is precisely regulated so as to precisely control the amount of pellets or granulated material moved from the hopper to the vessel. Alternatively, a controller can be provided for regulating several conveyor tubes, each to feed a different type of pellet or granular material into the vessel.

Abstract: A clutch-brake device having a housing, a shaft rotationally mounted therethrough, modular coupling units rigidly coupled to the shaft at either side of the housing, and an adapter which allows a single modular unit to be utilized interchangeably in either a clutch or a brake configuration. Each modular unit has a coupling member carrying an annular friction ring. The coupling member is rotationally connected to and spaced apart from a resilient disk defining a vacuum chamber therebetween. The resilient disk is rigidly attached to the modular unit and may be tapered towards the outer edge. The modular unit may also have several shims predisposed between the resilient disk and the coupling member which can be periodically removed to maintain the gap between the resilient disk and the annular friction ring within a preferred range. The device may have a microprocessor controlled high speed switch for controlling electromagnets which regulate engagement of the resilient disks.

Abstract: A fitting is provided to permit granular material carried in an air stream to be deposited within a storage vessel without having the air stream entering the storage vessel itself. The fitting has a tubular filter screen within the housing of the fitting and an air and dust exit port communicates with the filter screen to permit air and dust to be carried through this filter screen and out of the fitting housing. Because of the close proximity of the fitting to the storage vessel, the momentum of the granular material being carried through the fitting deposits the material within the storage vessel.

Abstract: A vacuum calibrator tool for use with a vacuum chamber is provided to accurately size and shape the outer surface of molten plastic extrudate entering the vacuum chamber. The tool provides water passages to introduce water into the extrudate receiving opening of the tool at several positions along the extrudate receiving opening so that an extended zone of water within the extrudate receiving opening provides a film of water between the vacuum calibrator tool and the extrudate passing through it to lubricate the extrudate and to permit accurate sizing and shaping of the extrudate. The vacuum calibrator tool is preferably formed of a low coefficient of friction plastic material such as glass filled polytetrafluroethylene solid commercially under the registered trademark TEFLON.RTM..

Abstract: A guide roller assembly is provided for use with a vacuum sizing apparatus having an elongated vacuum cooling tank containing a water bath through which plastic extrudate passes longitudinally. The guide roller assembly has a plurality of guide rollers each individually mounted on its own roller axle. A roller assembly pivot shaft is removably and pivotally secured within the elongated vacuum tank and supports the axles of the respective guide rollers. The guide rollers may be pivotally rotated between a working position where the axles are horizontal and the guide rollers bear down upon the extrudate passing through the vacuum cooling tank and a nonworking position where the guide rollers are raised above the water surface of the vacuum cooling tank and to one side of the tank. The entire guide roller assembly may be removed from the vacuum tank by retracting the telescoping pivot shaft and removing the ends of the pivot shaft from recesses formed in the end walls of the vacuum cooling tank.

Abstract: An improved underwater pelletizer is provided. The improved pelletizer has sealed heat transfer tubes embedded within the extruder die to utilize the heat of the molten polymer entering the extruder die by efficiently transferring that heat to the die plate and die face of the pelletizer. Ceramic inserts and/or inserts of other insulating materials are provided adjacent the die plate to insulate the passages through which the molten polymer passes and to inhibit cooling of the polymer within the extruder die as it approaches the die plate. The insulating inserts are positioned behind, and abut, the die plate around the passages that deliver the molten polymer to the die plate. Water makeup is provided at the cutter blades of the pelletizer to prevent cavitation within the water housing so that pellets will not agglomerate within the water housing.

Abstract: A centrifugal pellet dryer is provided which has a housing, a generally cylindrical mesh member vertically disposed within the housing and a rotor that is coaxial with the mesh member. The rotor has lifters which tend to move a slurry of pellets and water upwardly and outwardly relative to the cylindrical mesh member so that water moving radially through the mesh member is separated from the pellets which are retained by the mesh member. The rotor has a hollow interior portion that communicates with the bottom of the rotor so that the slurry of pellets of water are introduced into the dryer through the hollow interior of the rotating rotor. The slurry of pellets and water is distributed uniformly about the periphery of the mesh member by the rotating rotor and the rotation of the rotor enhances the centrifugal force of the slurry to initially dewater the slurry more effectively as the water moves radially outwardly through the mesh member.

Abstract: A dryer control system for controlling the drying of polymer plastic pellets within a dryer hopper is provided. A series of temperature snap switches and pressure switches are strategically located within the dryer control system to cause a variety of passive fault lights to be activated to signal faults while the system continues to operate or to cause an alarm light to be activated which stops the drying cycle. The passive fault lights indicate a situation within the drying cycle which should be corrected but which is not sufficiently serious to stop the drying cycle. An alarm being activated, on the other hand, indicates a situation which requires shut-down of the drying system until the problems which caused the alarm are corrected. A programmable logic controller and a temperature controller control the operation of the system by receiving signals from the snap switches and pressure switches throughout the system.

Abstract: An in-line tubing die for forming thin walled plastic tubing from molten plastic extrudate is provided. The hub of the tubing die is concentrically positioned within a housing and held in place by radially extending fins that join the housing to the hub. Every one of the fins that holds the hub within the housing has an air passage formed through it so that the fins are of a uniform temperature and the plastic extrudate flows uniformly around each of the fins to keep the thickness of the plastic tubing walls uniform around the entire circumference of the tubing. An annular groove or grooves are provided around the housing and are enclosed by a sheath which permits the air to circulate around the housing and be warmed to some extent before entering the passages within the fins and thereafter entering into the passage extending coaxially with the hub and into the interior of the plastic tubing.

Abstract: Apparatus and a method for the controlled drying of polymer plastic pellets within a dryer hopper are provided. A sensor tree having a plurality of temperature sensors spaced vertically on the tree is positioned vertically within the dryer hopper so that the individual sensors are each located at varying vertical distances from the bottom to the top of the dryer hopper. A target temperature for a particular type of polymer plastic pellet, when maintained for a specified residence time, indicates that the pellet is thoroughly dry for use in a manufacturing process. By determining the vertical level at which the target temperature has been achieved for the desired residence time, the amount of dry material within the hopper that is ready to be input to the manufacturing process is determined. A signal processing unit operating a software program automatically controls the throughput of the dryer hopper so that only dry polymer plastic pellets leave the hopper.

Abstract: A vacuum tank for a vacuum sizing apparatus is provided. The vacuum tank is especially suited to control with precision the size and cooling of small sized plastic extrudate. The vacuum tank has coolant tubes between the double walls of the tank so that the coolant is not directly exposed to the extrudate. A water make-up tube having very small holes in it is disposed below the surface of the water in the vacuum tank so that make-up water will enter the tank with a minimum of turbulence being created. Slots provided in a rotatable water over-flow tube permit the level of the water within the vacuum tank to be adjusted and the slots provide a non-turbulent exit of over-flow water from the vacuum tank. A pre-skin block is positioned within the vacuum tank and is designed to minimize turbulence of water at the pre-skinning position within the tank.

Abstract: A reciprocating gate valve for controlling the flow of particulate material is provided. The gate valve has a metal valve gate with an angled leading edge and also has a groove in the center of the angled leading edge. The valve body is formed from a metal cover plate that has a plurality of plastic body parts fixed to the cover plate so that the metal valve gate reciprocates between plastic body parts. The plastic body parts are preferably formed of self-lubricating plastic such as nylon or Teflon. The valve body has a rectangular recess which intersects the circular passage through the valve body with the rectangular recess having its long dimension positioned transverse to the direction of movement of the valve gate. The rectangular recess provides space for the particulate material to be moved ahead of the valve gate angled leading edge as the valve gate closes.

Abstract: A vacuum sizing apparatus with a controlled vacuum is provided. The vacuum is precisely controlled by the use of a variable speed motor driven vacuum pump and a step motor controlled vent valve. An electrical circuit containing a microprocessor coordinates the speed of the motor driven vacuum pump with the position of the vent valve to give precise vacuum control within the vacuum chambers of the sizing apparatus. A closed sump tank contains water for the water system of the apparatus and is maintained at the same vacuum level as the vacuum chambers within the sizing apparatus.