Semi-chemical pulp process

Claim 1

A SEMI-CHEMICAL PROCESS FOR PULPING WOOD CHIPS HAVING HARD DIRT-FORMING AND SHIVE-FORMING CONSTITUENTS THEREIN RESISTANT TO SOFTENING BY SEMI-CHEMICAL COOKING TREATMENT, TO PRODUCE PULP SUITABLE FOR USE IN THE MANUFACTURE OF HIGH GRADE WRIRING AND PRINTING PAPERS AND THE LIKE, WHICH COMPRISES COOKING SAID WOOD CHIPS WITH A SOFTENING LIQUOR THEREBY ONLY PARTIALLY TO REMOVE LUGNIN CONSITITUENTS THEREIN, SUBJECTING SAID COOKED CHIPS TO SUCH CONSTITUENTS THEREIN, SUBJECTING SAID COOKED CHIPS TO MILD SELECTIVE MECHANICAL DISINTEGRATION BY RELATIVE MOVEMENT ACROSS AN ABRADING SURFACE WHOSE CLEARANCE WITH RESPECT TO ANY OPPOSING SURFACE EXCEEDS THE SIZE OF THE LARGEST AGREGRATE UNDER TREATMENT, SUCH DISINTEGRATION BEING SUFFICIENT TO REDUCE THE SOFTENED PORTIONS OF THE CHIPS SUBSTANTIALLY TO AGGREGRATES OF FIBRES BUT NOT SEVERE ENOUGH TO REDUCE SUBSTANTIALLY THE SIZE OF SAID DIRT-FORMING AND SHIVE-FORMING CONSTITUENTS, SEPARATING SIAD FIBER AGGREGATES FROM SAID DIRT-FORMING AND SHIVE-FORMING CONSTITUENTS, DISCARDING SAID DIRT-FORMING AND SHIVE-FORMING