초록 ▼

A cutter hub position control device for consistent blade adjustment in an underfluid pelletizer is provided in connection with a motion rod attached to the pelletizer cutter hub and extending through a hollow shaft of the pelletizer motor. The cutter hub position control device can be collinear, tr

A cutter hub position control device for consistent blade adjustment in an underfluid pelletizer is provided in connection with a motion rod attached to the pelletizer cutter hub and extending through a hollow shaft of the pelletizer motor. The cutter hub position control device can be collinear, transaxial or in a plane parallel to the axis of the motion rod to which it is attached. Adjustment of the cutter hub position control device is automated through use of feedback control mechanisms.

대표청구항 ▼

1. An underwater pelletizer for extruding a polymer through an extrusion die having a cutting face comprising: a cutting chamber with transport fluid flowing therethrough for receiving extruded polymer;a cutter hub with attached cutting blades driven by a hollow drive shaft having a motion control r

1. An underwater pelletizer for extruding a polymer through an extrusion die having a cutting face comprising: a cutting chamber with transport fluid flowing therethrough for receiving extruded polymer;a cutter hub with attached cutting blades driven by a hollow drive shaft having a motion control rod passing therethrough, said cutter hub and cutting blades being positioned against said cutting face;a position control device for said cutter hub operatively coupled to said motion control rod for linearly moving said motion control rod within said drive shaft to position the cutter hub and cutting blades axially toward and away from the cutting face of the die;a first feedback mechanism configured to output data relating to pelletizer motor load amperes;a second feedback mechanism configured to output data relating to a linear distance between the cutter hub and the cutting face of the die; anda controller configured to receive an input from said first and second feedback mechanisms during operation of said pelletizer and to interpret said input to provide automated feedback to said cutter hub position control device to move the motion control rod toward and away from the cutting face to adjust the position of the cutter hub and cutting blades by a distance determined using the feedback mechanism input such that the cutter hub with attached cutting blades is adjusted during pelletizer operation to remain within a desired operating range with respect to the cutting face. 2. The pelletizer according to claim 1 wherein the cutter hub position control device is collinear with the motion control rod through the hollow drive shaft. 3. The pelletizer according to claim 1 wherein a longitudinal axis of the cutter hub position control device is in a plane parallel to that of the motion control rod through the hollow drive shaft, said position control device being drivingly attached to the motion control rod. 4. The pelletizer according to claim 3, wherein the cutter hub position control device is drivingly attached to the motion control rod using a driving mechanism of said cutter hub position control device that is drivingly connected to a driven mechanism attached to the motion control rod utilizing at least one of a chain and a belt. 5. The pelletizer according to claim 1 wherein the cutter hub position control device is in a plane different from that of the motion control rod and further comprising a manual control device attached collinearly with the motion control rod. 6. The pelletizer according to claim 1 wherein the cutter hub position control device includes a stepper motor, a microstepper motor or a servo motor. 7. The pelletizer according to claim 1 wherein said controller includes a programmable logic controller. 8. The pelletizer according to claim 7 wherein the cutter hub position control device also receives feedback relating to at least one of torque, degrees of rotation, vibration, and conductivity. 9. A method of controlling cutter blades relative to the cutting face of a die plate in an underwater pelletizer having a cutter hub and blades coupled to a motor-driven hollow drive shaft through which a motion control rod extends, said motion control rod being linearly movable within said motor-driven hollow drive shaft to move the cutter hub and blades axially toward and away from the cutting face of the die plate, said method comprising the steps of: moving the cutter hub away from the die plate to a first position based upon a position of the motion control rod, said first position defining a home position and a feedback lower limit;moving the cutter hub toward the die plate to a second position using the motion control rod until the blades are against the die face, said second position defining a starting position;operating the pelletizer;invoking at least one feedback mechanism using a controller to provide automated feedback to a cutter hub position control device during operation of the pelletizer, said automated feedback including data relating to pelletizer motor load amperes and linear distance moved by the motion control rod; andadjusting a position of the cutter hub and blades based on said automated feedback, said step of adjusting including moving the motion control rod and cutter hub toward and away from the cutting face by a linear distance determined from the automated feedback to maintain the pelletizer motor load amperes within a desired operating range that is reached when the cutter hub and blades are properly distanced from the die plate for pelletizer operation. 10. The method as set forth in claim 9, further comprising the step of setting a time period defining how frequently the position of the cutter hub is adjusted relative to the die plate in order to determine a next starting position for the cutter hub. 11. The method as set forth in claim 9, wherein the steps of moving the cutter hub away and toward the die plate include using a cutter hub position control device that is collinear with the motion control rod through the motor-driven hollow drive shaft. 12. The method as set forth in claim 9, wherein the steps of moving the cutter hub away and toward the die plate include using a stepper motor, a microstepper motor or a servo motor as a cutter hub position control device. 13. The method as set forth in claim 9, wherein the step of invoking a feedback mechanism further includes using the controller to provide automated feedback to a cutter hub position control device based on at least one parameter selected from the group consisting of forces of the extruded polymer, transport fluid flow rate, and rotation of the cutter hub itself. 14. The method as set forth in claim 9, further comprising the step of providing additional feedback to a cutter hub position control device relating to at least one of torque, degrees of rotation, vibration, and conductivity. 15. The method as set forth in claim 9, wherein the steps of moving the cutter hub away and toward the die plate include using a cutter hub position control device having a longitudinal axis that is in a plane parallel to that of the motion control rod through the motor-driven hollow drive shaft, said position control device being drivingly attached to the motion control rod utilizing at least one of a chain and a belt. 16. The method as set forth in claim 9, wherein the steps of moving the cutter hub away and toward the die plate include using a cutter hub position control device having a longitudinal axis that is transaxial to the motion control rod and the motor-driven hollow drive shaft and is drivingly attached to the motion control rod. 17. A method of controlling a position of cutter blades relative to the cutting face of a die plate in an underwater pelletizer having a cutter hub and blades coupled to a motor-driven hollow drive shaft through which a motion control rod extends, said motion control rod being linearly movable within said motor-driven hollow drive shaft to move the cutter hub and blades axially toward and away from the cutting face of the die plate, said method comprising: providing an underwater pelletizer with the cutter hub and blades coupled to a motor-driven hollow drive shaft through which a motion control rod extends, said motion control rod being linearly movable within said motor-driven hollow drive shaft to move the cutter hub and blades axially toward and away from the cutting face of the die plate, said pelletizer having a cutter hub position control device that is collinear with the motion control rod through the motor-driven hollow drive shaft;moving the cutter hub away from the die plate to a first position based upon a position of the motion control rod, said first position defining a home position;moving the cutter hub toward the die plate to a second position using the motion control rod until the blades are against the cutting face, said second position defining a starting position;setting a time period for pelletizer operation;operating the pelletizer;providing a controller with input from a first feedback mechanism and a second feedback mechanism during operation of said pelletizer, said first feedback mechanism providing the controller with data on pelletizer motor load amperes and said second feedback mechanism providing the controller with data relating to a linear distance of the blades from the die plate;after the time has elapsed, interpreting, by said controller, said input from said first and second feedback mechanisms to provide automated feedback to said cutter hub position control device, said cutter hub position control device using the automated feedback to determine linear movement of the motion control rod to adjust the position of the cutter hub and blades with respect to the cutting face so as to maintain the position of the cutter hub within a desired operating range and define a next starting position; andresetting the time period for pelletizer operation before determination of a next cutter hub position adjustment. 18. The method as set forth in claim 17, wherein said cutter hub position control device controls linear movement of the motion control rod to maintain the pelletizer motor load amperes within a desired operating range. 19. The method as set forth in claim 17, wherein the desired operating range includes a range of values determined by the first and second feedback mechanisms and relative to the home position and the starting position. 20. The method as set forth in claim 17, wherein the step of invoking a feedback mechanism further includes using a controller to provide automated feedback to said cutter hub position control device based on at least one parameter selected from the group consisting of forces of the extruded polymer, transport fluid flow rate, and rotation of the cutter hub itself.