Vacuum drying method and apparatus
AssigneeMaguire Products, Inc.
InventorsStephen B. MAGUIRE, Michael E. GERA
Life of this patent
Estimating the term…
Abstract
Method and apparatus for drying granular resin material by drawing vacuum over heating resin material in a vessel, while periodically purging the vessel with the material therein with dry air and bathing the vacuum dried material with dry air until furnished to a processing machine.
Claims24
A method for drying granular plastic resin prior to molding plastic into finished products comprising sequentially heating and vacuum drying batch portions of plastic resin material with a next succeeding batch portion being heated while a current batch portion is being vacuum dried.
Apparatus for drying granular resin material prior to molding or extrusion processing thereof, comprising:
- a. a heating chamber;
- b. a vacuum chamber below the heating chamber;
- c. a retention hopper below the vacuum chamber;
- d. a blower for supplying heated ambient air upwardly through the heating chamber;
- e. a conduit for introducing dry purge air into the vacuum chamber;
- and
- f. a conduit for introducing blanketing dry air into the retention hopper.
A method for drying granular resin material prior to processing thereof by molding or extrusion, comprising:
- a. heating granular resin material in a heating hopper;
- b. monitoring air temperature at the top of the heating hopper;
- c. regulating heat input to the heating hopper so that monitored air temperature at the top of the heating hopper dies not exceed a preselected temperature;
- d. releasing heated granular resin material from the heating hopper for flow downwardly into a vacuum chamber while replenishing the heating hopper from above with fresh resin material in an amount substantially equal to that released into the vacuum chamber;
- e. drawing vacuum in the vacuum chamber while periodically purging the vacuum chamber with dry air;
- f. draining resin material from the vacuum chamber into a retention hopper;
- g. blanketing resin material in the retention chamber with dry air.
In a method for drying granular resin material prior to processing thereof by molding or extrusion, the improvement comprising:
- a. introducing heated air into a granular resin material storage hopper at the hopper bottom;
- and
- b. monitoring the temperature of air leaving the hopper at a position above granular resin material in the hopper and regulating the rate of heated air introduction into the hopper so that monitored temperature of air leaving the hopper does not exceed a preselected level.
Dependencies are inferred from the claim text.