초록 ▼

Powdered starting material utilized for molding (e.g., rotational molding, injection molding, blow molding), extrusion, and the like can be preheated to reduce the time required to complete the processing of the material. After being preheated to a temperature below a melting temperature of the powd

Powdered starting material utilized for molding (e.g., rotational molding, injection molding, blow molding), extrusion, and the like can be preheated to reduce the time required to complete the processing of the material. After being preheated to a temperature below a melting temperature of the powder, the powder is transferred to a processing station. For example, in a rotational molding system, the preheated powder is transferred to a mold, where the preheated powder is melted and the mold is rotated such that the molten material adheres to the walls of the mold. After obtaining a desired distribution of the material over the walls of the mold, the temperature of the mold is decreased as rotation of the mold continues. When the article is sufficiently cooled, the article is removed from the mold.

대표청구항 ▼

What is claimed is: 1. A powder preheating system comprising: a first tube having an auger screw for moving a powdered material through the first tube; means for heating the first tube such that the powdered material moving through the first tube is heated to a predetermined temperature without mel

What is claimed is: 1. A powder preheating system comprising: a first tube having an auger screw for moving a powdered material through the first tube; means for heating the first tube such that the powdered material moving through the first tube is heated to a predetermined temperature without melting the powdered material, the means for heating being coupled to an outer portion of the first heated tube; a hopper coupled to the first heated tube and staged for dispensing the heated powdered material; and a second heated tube coupled to the first heated tube to facilitate recirculating the powdered material between the first and second heated tubes wherein the first and second heated tubes are disposed so that the powdered material moves through the second tube in a direction generally opposite to a direction in which the powdered material moves through the first tube. 2. The powder preheating system of claim 1, wherein the first and second heated tubes are heated via first and second water jackets having heated water flowing therethrough, the first and second water jackets substantially surrounding a circumference of the first and second heated tubes. 3. The powder preheating system of claim 2, wherein the first and second water jackets are baffled to facilitate even distribution of the water around the circumference of the first and second heated tubes. 4. A powder preheating system comprising: a first tube having an auger screw for moving a powdered material through the first tube; means for heating the first tube such that the powdered material moving through the first tube is heated to a predetermined temperature without melting the powdered material, the means for heating being coupled to an outer portion of the first heated tube; a hopper coupled to the first heated tube and staged for dispensing the heated powdered material; a second heated tube coupled to the first heated tube to facilitate recirculating the powdered material between the first and second heated tubes; and a third tube coupled to the first and second heated tubes to store the powdered material. 5. The powder preheating system of claim 4, wherein the first, second, and third tubes are coupled via a horizontal auger screw, the horizontal auger screw employed to move the powdered material between the first, second, and third tubes. 6. The powder preheating system of claim 5, wherein the horizontal auger screw includes a flight restrictor on a portion of the horizontal auger screw to control an amount of powdered material moving between the first, second, and third tubes. 7. The powder preheating system of claim 4, further comprising a normally closed gate coupled to a bottom portion of the third tube. 8. The powder preheating system of claim 4, wherein the third tube is heated via a water jacket substantially surrounding the third tube. 9. The powder preheating system of claim 4, further comprising a vacuum conveyor coupled to a top portion of the third tube to draw the powdered material from a storage container into the third tube. 10. The powder preheating system of claim 4, further comprising a sensor located in the third tube to sense when the powdered material is at or below a predetermined level. 11. The powder preheating system of claim 1, further comprising a sensor located in at least one of the first and second heated tubes to sense when the powdered material is at or below a predetermined level. 12. The powder preheating system of claim 1, further comprising a vibration chute coupled to the hopper to facilitate flow of the powdered material from the hopper. 13. The powder preheating system of claim 1, further comprising a first scale to measure an amount of powder to be colored. 14. The powder preheating system of claim 13, further comprising a second scale to measure an amount of powdered material dispensed from the hopper. 15. The powder preheating system of claim 1, further comprising a scale to measure an amount of powdered material dispensed from the hopper. 16. The powder preheating system of claim 1, further comprising a mixer to mix a pigment with the powdered material. 17. The powder preheating system of claim 16, further comprising a pigment receptacle to meter an amount of pigment into the mixer. 18. The powder preheating system of claim 1, wherein a portable electronic device is employed to operate the system. 19. The system according to claim 1, wherein the hopper has an inlet located at an outlet of the first heated tube and at an inlet of the second heated tube. 20. The system according to claim 1, wherein the powdered material is a material to be melted subsequent to heating in the system. 21. The system according to claim 1, wherein the powdered material is plastic to be molded.