US PATENT SUBCLASS 162 / 83
.~.~.~ Sulfur dioxide or sulfite

Current as of: June, 1999
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162 /   HD   PAPER MAKING AND FIBER LIBERATION

1  DF  PROCESSES OF CHEMICAL LIBERATION, RECOVERY OR PURIFICATION OF NATURAL CELLULOSE OR FIBROUS MATERIAL {33}
70  DF  .~ Treatment with particular chemical {9}
82  DF  .~.~ Sulfur containing {1}
83.~.~.~ Sulfur dioxide or sulfite {1}
84  DF  .~.~.~.~> Plural diverse stage treatment {2}

DEFINITION

Classification: 162/83

(under subclass 82) Processes in which a chemical containing a sulfite or free SO2 is employed.

SEE OR SEARCH THIS CLASS, SUBCLASS:

64, processes of digesting or treating fibers in which the fibers are contacted with sulfur dioxide in the gaseous state.