Vacuum drying method

Abstract

A method for drying granular plastic resin that is to be molded or extruded into finished parts mixes pre-determined weights of plastic resin material components into a homogeneous blend and sequentially heats and vacuum dries batch portions of the blend with a next succeeding batch portion being heated while a current batch portion is vacuum dried.

What is claimed is: 
     
         1 . A method for drying granular plastic resin that is to be molded or extruded, consisting of:
 a. mixing predetermined weights of plastic resin material components into a homogeneous blend; and   b. sequentially heating and vacuum drying batch portions of said blend with a next succeeding batch portion being heated while a current batch portion is vacuum dried.   
     
     
         2 . The method of  claim 1  further comprising performing step “b” to supply dried material at a desired rate of material consumption. 
     
     
         3 . The method of  claim 1  wherein said heating and drying step further comprises drying a batch portion of granular resin material that has been heated while said next succeeding batch portion is being heated. 
     
     
         4 . A method for drying batch portions of granular plastic resin that is to be molded or extruded into finished parts, comprising the steps of:
 a. mixing predetermined weights of granular plastic resin material components into a homogeneous blend; and   b. sequentially heating and vacuum drying batch portions of said blend with a next succeeding batch portion being heated at a first position while a current batch portion is vacuum dried at a second position vertically lower relative to the first position.   
     
     
         5 . A method for drying batch portions of plastic resin that are to be molded or extruded, comprising the steps of:
 a. mixing predetermined weights of plastic resin material components into a homogeneous blend;   b. sequentially heating and vacuum drying batch portions of said blend with a next succeeding batch portion being heated at a first position while a current batch portion is being vacuum dried at a second position vertically downwardly displaced from the first position;   c. moving said next succeeding batch portion via gravity induced flow from the first position where said hearing occurs to the second position where vacuum drying occurs; and   d. after vacuum drying, downwardly moving said current batch from said second position in preparation for molding or extrusion.   
     
     
         6 . The method of  claim 5  wherein the first and second positions are vertically aligned. 
     
     
         7 . The method of  claim 5  wherein the first and second positions are horizontally offset one from the other. 
     
     
         8 . A method for drying batch portions of plastic resin that is to be molded or extruded, comprising the steps of:
 a. mixing predetermined weights of plastic resin material components into a homogeneous blend;   b. sequentially heating and vacuum drying batch portions of said blend with a next succeeding batch portion being cylindrically restrained and heated at a first position while a current batch portion is cylindrically restrained and vacuum dried at a second position downwardly displaced from the first position;   c. moving said next succeeding batch portion downwardly via gravity induced flow from the first position, where said heating occurred while the next succeeding batch portion was cylindrically restrained, to the second position where vacuum drying occurs during cylindrical restraint of a subsequent batch portion being dried; and   d. after vacuum drying, downwardly moving said current batch from said second position in preparation for molding.   
     
     
         9 . The method of  claim 8  wherein the cylindrically restrained batch portions are axially aligned at the first and second positions. 
     
     
         10 . The method of  claim 8  wherein cylindrically restrained batch portions at the first and second positions are horizontally offset one from the other.