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A low pressure dryer for granular or powdery material includes a plurality of hoppers rotatable about a common vertical axis serially among material filling and heating, vacuum drying and material discharge positions; pneumatic piston-cylinder means for rotating the hoppers about said axis among sai

A low pressure dryer for granular or powdery material includes a plurality of hoppers rotatable about a common vertical axis serially among material filling and heating, vacuum drying and material discharge positions; pneumatic piston-cylinder means for rotating the hoppers about said axis among said filling and heating, vacuum drying and discharge positions; means for heating contents of a hopper at said filling and heating positions; means for sealing a hopper at said vacuum and drying positions; means for drawing vacuum within a hopper at said vacuum drying position and means for selectably permitting downward flow of dried granular or powdery material out of a hopper at said discharge position where said hoppers move collectively and unitarily one with another.

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1. A low pressure dryer for granular or powdery material, comprising: a. a plurality of hoppers rotatable about a common vertical axis serially among material filling and heating, vacuum drying and material discharge positions;b. a plurality of pneumatic piston-cylinder combinations for rotating sai

1. A low pressure dryer for granular or powdery material, comprising: a. a plurality of hoppers rotatable about a common vertical axis serially among material filling and heating, vacuum drying and material discharge positions;b. a plurality of pneumatic piston-cylinder combinations for rotating said hoppers about said axis among said filling and heating, vacuum drying and discharge positions;c. means for heating contents of a hopper at said filling and heating position;d. means for sealing a hopper at said vacuum drying position;e. means for drawing vacuum within a hopper at said vacuum drying position; andf. means for selectably permitting downward flow of dried granular or powdery material out of a hopper at said discharge position. 2. DryerThe dryer of claim 1 further comprising: a. a vertical shaft defining said vertical axis;b. said pneumatic piston-cylinder combinations being equiangularly positioned about said shaft for rotating said shaft and thereby said hoppers. 3. DryerThe dryer of claim 1 wherein said hoppers are open-ended, generally vertically oriented cylindrical configuration and equiangularly positioned respecting a vertical axis. 4. A hopper for use in a low pressure granular or powdery material dryer comprising: a. a vertically-oriented cylindrical shell having open ends, adapted to be sealingly closed by selectably contacting top and bottom plates thereagainst, enabling vacuum to be drawn within said shell when said shell is at a vacuum drawing position;b. a funnel within said cylindrical shell proximate the bottom thereof;c. an internal material flow control plate located within said cylindrical shell beneath said funnel, pivotally connected to said cylindrical shell for movement about said connection away from a downwardly opening discharge orifice in said funnel to a position permitting downward granular resin material flow from said hopper. 5. HopperThe dryer of claim 41 in which said means for sealing said hopper at said vacuum drying position further comprisingcomprises: a. top and bottom plates for selectively sealing saida cylindrical shell of said hopper allowing vacuum to be drawn therein;b. pneumatic piston-cylinder means for urging said top and bottom plates into sealing contact with said shell; said shell being adapted to selectively dispense granular material stored therein at a dispense position removed from said vacuum drawing position. 6. A method for continuously drying granular or powdery material preparatory to mixing, molding, extruding or other processing of that material, comprising the steps of: a. supplying granular or powdery material to a vertically-oriented cylindrical shell at a fill and heat position and heating said material within said shell by introduction of heated air into said cylinder;b. moving said vertically-oriented cylindrical shell through an arc about a vertical axis outboard of the shell periphery to a vacuum drying position and sealing open ends of said shell thereat;c. drawing a preselected level of vacuum within said sealed shell for time sufficient to evaporate moisture from said heated material to a desired degree of dryness;d. moving said shell to a discharge position at which said shell is open;e. discharging said dried material from said cylindrical shell responsively to a pneumatic piston-cylinder combination actuating a material discharge gate proximate the bottom of said shell; andf. moving said shell through an arc about said vertical axis to a fill and heat position and sequentially repeating steps (a) through (d)(e) for so long as saidsuch granular plasticor powdery material is to be continuously dried. 7. A method for continuously supplying dried granular resin material for processing from a supply of material which is excessively moist, comprising substantially simultaneously performing the steps of: a. heating a portion said moist material to a selected temperature at which said moisture evaporates therefrom at a preselected level of vacuum;b. drawing and maintaining said preselected level of vacuum for a second portion of said material which has been heated to said selected temperature for a time sufficient to cause said moisture to evaporate therefrom and result in said second portion of material being at a preselected dryness; andc. supplying to granular resin material processing equipment a third portion of said material which has been dried to said preselected dryness by evaporation in said preselected level of vacuum after being heated to said selected temperature. 8. The method of claim 7 wherein said portions are serially supplied. 9. A method for continuously drying granular or powderyplastic resin material in batches preparatory to mixing, molding,or extruding or other processing of that material into intermediate or finished products, comprising the steps of: a. supplying granular or powdery material to a closeable shell at a fill position;b. heating said material within said shell while at the fill position by introduction of heated air thereinto;c. moving said shell to a vacuum drying position and sealing said shell thereat;d. drawing a preselected level of vacuum within said sealed shell for time sufficient to evaporate moisture from said heated material to a desired degree of dryness;e. moving said shell to a discharge position at which said shell is opened;f. discharging said dried material from said shell; andg. moving said shell to said fill position and sequentially repeating steps (a) through (f) for so long as saidsuch granular plasticresin material is to be continuously dried. 10. The method of claim 9 wherein said heating further comprises introducing air into said shell at a desired material temperature, measuring temperature of said air as it existsexits said shell, comparing said exit air temperature to said desired temperature and halting heating when said exit air reaches said desired temperature. 11. The method of claim 9 wherein said heating further comprises capturing heating air leaving said shell for recycling through said shell. 12. The method of claim 10 wherein said heating further comprises capturing heating air leaving said shell for recycling through said shell. 13. A low pressure dryer for granular or powdery material, comprising: a. a shell movable among material filling and heating, vacuum drying and material discharge positions;b. means for moving said shell serially among said filling and heating, vacuum drying and discharge positions;c. means for heating contents of said shell at said filling and heating position;d. means for drawing vacuum within a said shell at said vacuum drying position; ande. means for selectably permitting downward flow of dried granular or powdery material out of a shell at said discharge position. 14. The dryer of claim 13 further comprising: a. means for sealing said shell at said vacuum drying position. 15. A low pressure dryer for granular or powdery material, comprising: a. a plurality of shells movable among material filling and heating, vacuum drying and material discharge positions;b. means for moving said shells serially simultaneously among said filling and heating, vacuum drying and discharge positions;c. means for heating contents of a shell at said filling and heating position;d. means for drawing vacuum within a shell at said vacuum drying position; ande. means for selectably permitting downward flow of dried granular or powdery material out of a shell at said discharge position. 16. The dryer of claim 15 further comprising: a. means for sealing a shell at said vacuum drying position. 17. The dryer of claim 15 wherein said shells are collectively movable among material filling, drying and discharge positions. 18. A low pressure dryer for granular or powderyplastic resin material, comprising: a.(a) a plurality of sealable closeable shells collectablyspaced one from another, each being movable serially among material filling/heating, drying and discharge positions;b.(b) means for moving said shells among said filling/heating, drying and discharge positions;c.(c) means for heating shell contents prior to arrival at said dryingfilling/heating position by blowing hot air through the shell contents;d.(d) means for sealing said shells at said drying position;e.(e) means for drawing vacuum of at least about 27.5 millimeters of mercury over the shell contents within said sealed shells at said drying position; andf.(f) means for emptyingopening bottoms of said sealed shells at said discharge position to permit downward flow of dried granular or powderyplastic resin material from said shells at said discharge position. 19. A low pressure dryer for granular or powdery material, comprising; a. a plurality of shells serially movable around a circuit along which said shells are filled emptied, heated and vacuum dried;b. means for moving said shells around said circuit for filling and emptying said shells and heating and vacuum drying of material in said shells;c. means for heating said shells prior to drying;d. means for sealing said shells for drying;e. means for drawing vacuum within said shells during drying; andf. means for emptying dried granular or powdery material from said shells after drying. 20. A hopper for use in a granular plastic resin material vacuum dryer comprising: a. a shell having an opening, for discharge of granular plastic resin from the bottom of the shell, that is sealingly closeable by selectably movably contacting sealing means thereagainst, enabling vacuum to be drawn within said shell;b. a downwardly tapering funnel, the upper extremity of the funnel contacting the shell interior, for collecting and channeling downwardly flowing granular plastic resin material towards said opening, positioned within said shell proximate the bottom thereof;c. a dump flap located within said shell beneath said funnel, pivotally connected to the shell interior for movement about said connection away from a position blocking downward flow of granular plastic resin material towards a downwardly opening discharge orifice in said funnel, to a position remote from downwardly opening discharge aperture in the funnel thereby permitting downward granular resin material flow through the funnel and the opening in the shell, thereby exiting said hopper. 21. The hopper of claim 20 wherein said shell is cylindrical and further comprises concentric inner and outer tubes and a second downwardly tapering funnel positioned above the first funnel and having funnel angle in common therewith, the upper extremity of the second funnel contacting the interior of the inner tube, for collecting and channeling downwardly flowing granular plastic resin material towards said first funnel. 22. A method for drying granular plastic resin material in batches preparatory to molding or extruding of that material into intermediate or finished products, without heating the material to above a preselected desired temperature, comprising the steps of: c. supplying granular plastic resin material to a movable closeable shell while the shell is at a first location;d. heating said material to a desired temperature within said movable closeable shell while at the first location by; i. heating air to the desired material temperature;ii. blowing the heated air through the material in the shell;iii. measuring the temperature of the air as it exits the shell;iv. comparing the exit air temperature to the desired material temperature;v. capturing the heated air as it exits the shell and recycling the air through the shell after heating step “i”, andvi. halting heating and blowing the air when the exit air temperature equals the desired material temperature;e. drawing a vacuum of at least 27.5 millimeters of mercury within said movable closeable shell while at a second location at which said shell is closed for time sufficient to evaporate moisture from said heated material to a desired degree of dryness;f. discharging said dried material from said shell by opening the closed shell and permitting the dried material to flow downwardly out of the shell: andg. sequentially repeating steps (a) through (d) for so long as said granular plastic resin material is to be dried in batches to thereafter be molded or extruded into intermediate or final products. 23. A method for continuously drying granular plastic resin material in batches preparatory to molding or extruding that material into intermediate or finished products, comprising the steps of: a. supplying granular plastic resin material to a movable closeable shell while the shell is at a first location;b. heating said material within said shell while at the first location by recycling heated air around a closed loop of which said shell forms at part only when at said first location;c. drawing a preselected level of vacuum within said closeable shell while at a second location at which said shell is closed for time sufficient to evaporate moisture from said heated material to a desired degree of dryness;d. discharging said dried material from said shell by opening the closed shell and permitting the dried material to flow downwardly out of the shell: ande. sequentially repeating steps (a) through (d) for so long as said granular plastic resin material is to be continuously dried in batches to thereafter be molded or extruded into intermediate or final products.